II. INDUSTRIAL POISONING IN PARTICULAR INDUSTRIES
After the foregoing general remarks we may now consider various points of view in regard to classification of industrial poisonings into groups:
(1) Toxicological, based on the action of the poisons.
(2) Chemical, based on the chemical composition of the poisons.
(3) Physical, based on the varying density of the poisons. (Division into solid (in form of dust), gaseous, and liquid poisons.)
To which may be added:
(4) Classification according to the source of the poisoning and therefore according to industry, upon which Part I is mainly based.
In this section (Part II) a system is adopted which takes into consideration as far as possible all the principles of division mentioned above, in order to classify industrial poisonous substances in such a manner that general practical conclusions can be clearly drawn, and supervision rendered easy.
GROUP: MINERAL ACIDS, HALOGENS, INORGANIC HALOGEN COMPOUNDS, ALKALIS
Common to this group is a strong corrosive and irritant effect, varying however in degree; as gases this group corrode or inflame the mucous membrane of the respiratory passages, and in liquid form or in solution, the skin.
Besides this superficial effect single members of this group, especially those containing nitrogen, produce a remote effect upon the blood.
After absorption of the acids a decrease in the alkalinity of the blood can take place and in its power to take up carbonic acid, thus vitally affecting the interchange of gases in the body, and producing symptoms of tissue suffocation.
As regards treatment in the case of acids and alkalis, neutralisation has been already mentioned; further, oxygen treatment may be recommended in cases where the blood has been injuriously affected. In cases of poisoning through breathing in acid vapours, inhalation of extremely rarefied vapour of ammonia or of a spray of soda solution (about 1 per cent.) is advisable.
MINERAL ACIDS
Hydrochloric Acid (HCl) is a colourless, pungently smelling gas which gives off strong white fumes. Experiments on animals, carefully carried out by Leymann, produced the following symptoms.
Even in a concentration of 2-5 per thousand clouding of the cornea ensues, and after about an hour inflammation of the conjunctiva, violent running from every exposed mucous membrane with marked reddening, and frequently inflammation (necrosis) of the septum of the nose; the lungs are distended with blood, here and there hæmorrhages occur in the respiratory and also in the digestive tracts. The animal dies of œdema (swelling) of the lungs and hæmorrhage into the lungs if exposed long enough to the action of HCl, even though (according to Lehmann) there may not be accumulation of HCl in the blood; the chief effect is the irritant one; 1·5-5 per thousand parts HCl in the air suffices, after three or four hours’ exposure, to affect smaller animals (rabbits) so much that they die during the experiment or shortly after it. Man can tolerate an atmosphere containing 0·1 to 0·2 per thousand HCl; a somewhat greater proportion of HCl produces bronchial catarrh, cough, &c.
The solution of hydrochloric acid in water is about 40 per cent. Simply wetting the skin with concentrated solution of hydrochloric acid does not generally have an irritant effect unless persisted in for some time; the action of the acid, when continued, has a marked effect upon the mucous membranes and upon the eyes.
The same treatment already recommended in the introductory remarks on poisoning by inhalation of acid fumes in general applies.
Hydrofluoric Acid (HFl), a pungently smelling, colourless gas, causes even in weak solutions (0·02 per cent.) irritant symptoms (catarrh of the mucous membrane of the respiratory organs, lachrymation, &c.). Stronger solutions set up obstinate ulcers, difficult to heal, in the mucous membrane and the skin.
Silico-fluoric Acid (H₂SiFl₆) produces an analogous though somewhat less marked corrosive action.
As regards treatment the reader is again referred to the introductory sentences on this group.
Sulphur Dioxide (SO₂) is a colourless, pungently smelling gas which, acting in low concentration or for a short period, causes cough and irritation of the mucous membrane of the respiratory passages and of the eyes; acting for a longer period, it sets up inflammation of the mucous membrane, bronchial catarrh, expectoration of blood, and inflammation of the lungs.
As Ogata and Lehmann have proved by experiments—some of them made on man—a proportion of 0·03-0·04 per thousand of sulphur dioxide in the air has a serious effect on a person unaccustomed to it, while workmen used to this gas can tolerate it easily.
As sulphur dioxide probably does not affect the blood, treatment by oxygen inhalation is useless. Otherwise the treatment spoken of as applying to acid poisonings in general holds good.
Sulphuric Acid (H₂SO₄). Concentrated sulphuric acid occasionally splashes into the eye or wets the skin, causing severe irritation and corrosion, unless the liquid is quickly washed off or neutralised. If the action of the acid persists, the corrosive effect becomes deepseated and leads to disfiguring scars.
Nitrous Fumes, Nitric Acid.—Nitric oxide (NO) oxidises in the air with formation of red fumes composed of nitrogen trioxide (N₂O₃) and nitrogen peroxide (NO₂). These oxides are contained in the gases evolved from fuming nitric acid and where nitric acid acts upon metals, organic substances, &c.
Industrial poisoning by nitrous fumes is dangerous; unfortunately it frequently occurs and often runs a severe, even fatal, course; sometimes numerous workers are poisoned simultaneously. The main reason why nitrous fumes are so dangerous is because their effect, like that of most other irritant gases, is not shown at once in symptoms of irritation, such as cough, cramp of the glottis, &c., which would at least serve as a warning to the affected person; on the contrary, generally no effect at all is felt at first, especially if the fumes are not very concentrated. Symptoms of irritation usually appear only after some hours’ stay in the poisonous atmosphere. By this time a relatively large quantity of the poisonous gas has been absorbed, and the remote effect on the blood induced.
The first symptoms of irritation (cough, difficulty of breathing, nausea, &c.) generally disappear when the affected person leaves the charged atmosphere, and he then often passes several hours without symptoms, relatively well. Later severe symptoms supervene—often rather suddenly—difficulty of breathing, fits of suffocation, cyanosis, and copious frothy blood-stained expectoration with symptoms of inflammation of the bronchial tubes and lungs. These attacks may last a longer or shorter time, and in severe cases can lead to death; slight cases end in recovery, without any sequelæ.
In poisoning by nitrous acid fumes, oxygen inhalation, if applied in time, undoubtedly holds out hope of success, and should always be tried. Chloroform has been repeatedly recommended as a remedy. Probably its inhalation produces no actual curative effect, but only an abatement of the symptoms through the narcosis induced.
Nitric acid (HNO₃) in solution has an irritant corroding action if, when concentrated, it comes into contact with the skin or mucous membrane.
THE HALOGENS (CHLORINE, BROMINE, IODINE)
Chlorine (Cl) is a yellow-green, pungently smelling gas, Bromine (Br) a fuming liquid, and Iodine (I) forms crystals which volatilise slightly at ordinary temperatures.
According to Lehmann’s experiments on animals the effect of chlorine gas and bromine fumes is completely similar. Lehmann and Binz assume that chlorine has a twofold effect: (1) narcotic, paralysing the outer membrane of the brain, and (2) the well-known irritant action upon the mucous membrane, producing a general catarrh of the air passages, and inflammation of the lungs; it is, however, only the latter which causes menace to life. Other writers do not mention the narcotic effect upon the brain and assume that the halogens when brought into contact with the mucous membrane are quickly converted into halogen hydrides, and, as such, produce a corrosive effect. According to Lehmann, even 0·01 per thousand Cl or Br in the air is injurious, even 0·1 per thousand produces ulceration of the mucous membrane, and one or two hours’ exposure to the poison endangers life. Lehmann has further tested (on dogs) acclimatisation to chlorine, and finds that after a month the power of resistance to chlorine appears to be increased about ten times. In a further series of experiments the same author has proved that even the smallest quantities of chlorine present in the atmosphere are completely absorbed in breathing.
Continued or frequent action of chlorine upon the organism produces symptoms which have been described as chronic chlorine poisoning—such as anæmia and indigestion, in addition to catarrhal and nervous symptoms. Further, in factories where chlorine is produced by the electrolytic process, workers were found to be suffering from the so-called chlorine rash (first observed by Herxheimer). This skin disease consists in an inflammation of the glands of the skin, with occasional development of ulcers and scars. Severe cases are accompanied by digestive disturbance. Bettmann, Lehmann, and others maintain that it is not caused by chlorine alone, but by chlorinated tar products, which are formed in the production of chlorine and hydrochloric acid.
In acute cases of chlorine poisoning oxygen treatment should be tried, but in any case the patient should have free access to pure air. Approved remedies are inhalation of soda spray or very dilute ammonia, or of a vapourised solution of sodium hypochlorite. If the patient is in great pain, he may be allowed to inhale cocaine solution (0·2 per cent.).
The administration of arsenic (solutio arsenicalis) is recommended, especially in cases of acne. In general the usual treatment for diseases of the skin is followed; salicylic acid lotions, sulphur baths, and sulphur ointments may be made use of.
Chlorides.—Chlorides of Phosphorus, Phosphorus-trichloride (PCl₃), and Phosphorus oxychloride (POCl₃), are strong-smelling liquids, fuming in the air, and when brought into contact with water decomposing into phosphorous acid and hydrochloric acid. These halogen compounds of phosphorus have a violently irritant action upon the respiratory organs and the eyes, in that they decompose on the mucous membrane into hydrochloric acid and an oxyacid of phosphorus. Inhalation of the fumes of these compounds causes cough, difficulty of breathing, inflammation of the respiratory passages, and blood-stained expectoration.
Treatment is similar to that for acid poisoning in general and hydrochloric acid in particular.
Similar to that of the chlorides of phosphorus is the action of chlorides of sulphur, of which sulphur monochloride (S₂Cl)₂ is of industrial hygienic importance as it is employed in the vulcanising of indiarubber. It is a brown, oily, fuming liquid, which, mixed with water or even in damp air, decomposes into sulphur dioxide and hydrochloric acid. The fumes of sulphur monochloride have therefore a marked irritant effect, like that of hydrochloric acid and sulphur dioxide. The action of sulphur chloride was thoroughly studied by Lehmann. Industrial poisoning by sulphur chloride is mentioned by Leymann and also in the reports of the Prussian factory inspectors for 1897. The latter case ended fatally owing to the ignorance of the would-be rescuers: a workman had spilt trichloride of phosphorus upon his clothes, and the by-standers, not knowing its dangerous action when combined with water, poured water on him.
Treatment is similar to that of poisoning from hydrochloric acid or sulphur dioxide.
Chloride of zinc (zinc chloride, ZnCl₂) likewise has corroding and irritant action upon the mucous membrane of the respiratory organs.
AMMONIA
Ammonia (NH₃) is a colourless, pungent-smelling gas which dissolves to the extent of about 33 per cent. in water. Inhaled, it first produces violent reflex coughing, then irritation and corrosion of the mucous membrane of the respiratory organs, and finally death through suffocation (spasm of the glottis) if exposure to its action has lasted a sufficiently long time. Microscopic sections exhibit a diphtheritic appearance of the mucous membrane, and inflammation of the lungs. The effects upon the central nervous system (irritation of the medulla and spinal cord) which are peculiar to ammonia compounds need not be considered, as the corrosion of the respiratory passage is sufficient alone to cause death. When the action of the gas is less intense, the patient rallies from the first stage, but often severe symptoms come on later affecting the lungs.
Lehmann in experiments upon himself could tolerate as much as 0·33 per thousand NH₃ for thirty minutes; he found in gas works (with fairly marked odour) hardly more than 0·1 per thousand NH₃ in the atmosphere, and considers 0·5 per thousand distinct evidence of excess. He found that he could produce in dogs acclimatisation up to 1·0 per thousand NH₃ (five times as much as could at first be borne). About 88 per cent. of the ammonia contained in the air is absorbed in breathing; ammonia is said to exercise also a reducing action upon the oxygen of the blood (oxyhæmoglobin).
Chronic poisoning by ammonia can hardly be said to occur. In those who clean out sewers and drains, the inflammation of the eyes and digestive disturbance attributed partly to ammonia are probably due more to the action of sulphur compounds—ammonium sulphide and sulphuretted hydrogen. Irritation due to solution of ammonia does not come into account in industrial employment.
As regards treatment, fresh air or administration of oxygen is most likely to be successful. Inhalation also of very dilute acetic acid vapour, steam, or spray of sodium carbonate is advocated.
ALKALIS
The alkaline hydroxides (potassium and sodium hydroxide, KOH, NaOH) have an albumen-dissolving and therefore caustic effect. Industrially it occurs in the caustic action of concentrated (often hot) lyes upon the skin or upon the eye—through splashing. Quicklime (CaO) has also a caustic action, producing inflammation of the skin or eyes (especially in those engaged in the preparation of mortar).
Under this head comes also the effect upon the respiratory passages—described by several authors—caused in the production of artificial manure discussed at length in Part I.
As regards treatment of the irritant effect of alkalis, what has been said as to corrosives in general applies here (rinsing with water or weak organic acids), and in inflammation of the eye caused by lime a drop of castor oil is recommended.
GROUP: METALS AND METAL-COMPOUNDS
The various substances of this group differ markedly in their action. Under this heading come principally chronic metal poisonings, characterised by a general, often very intense, disturbance of nutrition, which justifies their delineation as ‘metabolic poisons’; among these poisons also are included certain others which produce chronic poisoning accompanied by severe disturbance of the peripheral and central nervous system.
The corrosive action common to the metal oxides (when acting in a concentrated condition), attributable to the formation of insoluble albuminates, need not, in industrial poisoning, be taken so much into account. The corrosive effect is characteristic only of the compounds, especially of the acid salts of chromium, which, as an acid-forming element, may be classed in the preceding group. Disturbance of health in workmen handling nickel compounds are also ascribed to the corrosive action of these substances.
LEAD, LEAD COMPOUNDS
Lead poisoning is the most frequent and important chronic industrial poisoning; the symptoms are very varied and associated with the most different groups of organs. We shall describe the typical course of a case of industrial lead poisoning, laying stress, however, on the fact that numerous cases follow an irregular course, in that special symptoms or complications of symptoms are in some especially accentuated, while in others they become less marked or are absent altogether.
A premonitory indication of chronic lead poisoning is a blue line on the gum, indicated by a slate gray or bluish black edging to the teeth, the appearance of which is usually accompanied by an unpleasant sweetish taste in the mouth. The cause of this blue line was for some time disputed. It is obviously due to the formation and deposit of sulphide of lead through the action of sulphuretted hydrogen arising from decomposition in the mouth cavity. At the same time a general feeling of malaise and weakness often comes on, occasionally accompanied by tremor of the muscles and disinclination for food, at which stage the sufferer consults the doctor. Frequently he complains also of pains in the stomach, not difficult to distinguish from the lead colic to be described later. Usually the patient already exhibits at this stage general emaciation and marked pallor.
The blue line was formerly considered a characteristic early indication of lead poisoning; but it has now been proved that occasionally it is absent even in severe attacks. But although the blue line may fail as an ‘initial symptom,’ it will nevertheless be a valuable aid to the practitioner in the recognition of lead poisoning. It is worth while to mention the fact that other metallic poisons produce a very similar ‘line,’ especially mercury, also iron and silver (as in the case of argyria); it has been stated that the blue line can be simulated by particles of charcoal on the gum. The pallor of the patient at the commencement of lead poisoning drew attention to the condition of the blood. The diminution in the amount of hæmoglobin often met with, which under certain circumstances is accompanied by diminution of the red blood cells, offers nothing characteristic. On the other hand, structural changes in the red blood cells—presence of basophil granules in them—are asserted by a number of writers to be characteristic of the first stages of lead poisoning. The basophil granules are believed to be due to regenerative changes in the nucleus. But these changes are also found in pernicious anæmia, cancer, leucæmia, anæmia, tuberculosis, &c.; also in a number of poisonings such as phenylhydrazine, dinitrobenzene, corrosive sublimate, and others; they are therefore the less characteristic of chronic lead poisoning, as occasionally they cannot be found in actual lead poisoning, a point upon which I have convinced myself in the case both of men and animals. Still, the appearance of much basophilia in the red blood cells is a valuable aid to diagnosis, especially as the method of staining to demonstrate them is simple.
Other anomalies of the blood observed in lead poisoning may here be mentioned. Glibert found a striking diminution in the elasticity of the red blood corpuscles, and experiments I have made point to the fact that the power of resistance of the red blood corpuscles to chemically acting hæmolytic agents, such as decinormal soda solution, is considerably reduced.
The pulse is generally hard and of high tension, especially during the attacks of colic. Further, cramp of the bloodvessels (also in the retinal arteries) has been observed. To these functional disturbances in the circulation are added sometimes definite changes in the vessel wall. Later, obliterative arteritis comes on (in the brain arteries), and arteriosclerosis.
The most important symptom of fully developed lead poisoning is colic, which is usually preceded by the initial symptoms described (especially the gastric symptoms), but not always so, as occasionally colic sets in without any warning. The colic pains often set in with marked vehemence. They radiate from the navel on all sides, even through the whole body; the abdomen is contracted and as hard as a board. Pressure on the lower part diminishes the pain somewhat, so that the sufferer often involuntarily lies flat on his stomach. During the attack the pulse is often remarkably slow. Constipation occurs, and often does not yield to purgatives. The attacks last sometimes for hours, occasionally for days, or the pains can (with remissions) even distress the patient for weeks. The frequency of attacks is also very variable. Occasionally one attack follows another, often there are intervals of weeks, even years, according to the severity of the poisoning and duration of exposure. If the patient is removed from the injurious action of lead, as a rule recovery soon ensues.
Fig. 34.—Paralysis of the Ulnar Nerve in Lead Poisoning
Fig. 34a.—Different Types of Paralysis of the Radial Nerve in Hungarian Potters poisoned by Lead (after Chyzer)
Often with the colic, or at any rate shortly after it, appear lead tremor and arthralgia, paroxysmal pain mostly affecting the joints, but occasionally also the muscles and bones. They are often the precursor of severe nervous symptoms which affect the peripheral and central nervous system. In a lead poisoning case running a typical course the predominant feature is the peripheral motor paralysis of the extensors of the forearms. Next the muscles supplied by the radial and ulnar nerves are affected. Often the progress of the paralysis is typical; it begins with paralysis of the extensor digitorum communis, passes on to the remaining extensors, then to the abductor muscles of the hand; the supinator longus and triceps escape. Sometimes the shoulder muscles are attacked; also paralysis in the region supplied by the facial nerve and of the lower extremities is observed. It appears plausible that overstrain of single groups of muscles plays a decisive part; this seems proved by the fact that paralysis first affects, among right-handed people, the right hand (especially of painters), but in the case of left-handed, the left hand; and among children the lower extremities are often attacked first. Disturbance of sight increasing to amaurosis is often an indication of severe brain symptoms. The view of some writers that the cause of the sight disturbance lies in vasomotor influences (cramp of the bloodvessels) is very probable, and supports the view that the brain symptoms are entirely due to diseases of the arteries (arteritis). These symptoms are distinguished by the collective name of saturnine encephalopathy; they include apoplexy, hemiplegia, epilepsy, delirium, and mania. The brain symptoms may cause death.
As later symptoms of lead poisoning may be mentioned lead gout and kidney disease (lead nephritis). The genesis of both these diseases is much disputed. It seems to be proved that the gout is true gout (with presence of tophi) and that the contracted kidney is indistinguishable from ordinary chronic Bright’s disease.
The kidney symptoms suggest that a regular excretion of lead through the urine takes place which, if it were a fact, would have been an important aid to diagnosis. But often analysis of urine for presence of lead is negative. Excretion of lead by the skin is scarcely to be credited, although occasionally affirmed. Elimination of lead is effected mainly through the intestines (probably for the most part as sulphide of lead).
All lead compounds more or less are to be regarded as poisonous, although the intensity of the action depends on the amount absorbed. For this its solubility in water or in weak acids (hydrochloric acid of the gastric juice) is the simplest test. According to this acetate of lead, lead chloride, carbonate of lead (white lead), oxide of lead (lead dross), minium (red oxide of lead) are relatively the most poisonous. Lead sulphate and lead iodide are to be regarded as relatively less poisonous, although by no means innocuous. The least poisonous, if not altogether innocuous, is sulphide of lead, because it is an insoluble lead compound.
Treatment of lead poisoning ought to aim first and foremost at the elimination of lead from the body. But unfortunately such attempts have had little success. Treatment of symptoms is all that for the most part is possible. Administration of iodide of potassium to assist the excretion of lead has not been found the success which many anticipated. This remedy however, can be tried; better results are to be expected from careful regulation of the bowels by means of purgatives. During colic administration of opium or morphia may be advisable to relieve pain and overcome the probable cramp of the intestinal muscles. The cautious administration of atropine (occasionally with cocaine) also serves the same purpose. Hot compresses and mustard plasters may be applied, and liquid diet should be given. Lead cachexia must be treated by strengthening diet. Electrical treatment for lead paralysis is advocated. From baths (sulphur baths) nothing more is to be expected than a bracing effect—elimination of lead through increased diaphoresis is hardly to be hoped for.
ZINC (ZINC ALLOYS)
Zinc (Zn) melts at 412° C. and distills at about 900° C.; exposed to the air it burns, when heated, into zinc oxide. Older writers, when investigating gastric and intestinal diseases and affections of the nervous system observed in zinc smelters, regarded them as the result of chronic zinc poisoning; but it may now be accepted as certain that these symptoms are due to the lead always present in the zinc.
On the other hand so-called brass-founders’ ague may be regarded as a form of acute industrial zinc poisoning. Brass-founders’ ague occurs exclusively in brass casters, and not in zinc workers. Sigel and Lehmann have shown that founders’ ague is also caused by pure zinc if this is heated so strongly that it burns.
Premonitory symptoms often occur before the onset of the disease; usually they appear early, soon after casting has begun. The workman has general malaise accompanied by slight cough, nausea, throat irritation, &c., but these symptoms mostly disappear, returning again after a few hours with renewed violence, often in the evening before going to bed. Frequently, trembling sets in rather suddenly, often accompanied by headache, nausea, and muscular pains, and soon develops into a pronounced shivering fit, lasting generally about a quarter of an hour, but in severe cases for several hours (with intervals). At the same time the breathing is hurried and the heart’s action quickened (asthma and palpitation). Often the temperature rises as high as 104° F. The attack ends with profuse perspiration, and the patient sinks exhausted to sleep, awaking in the morning generally quite restored or with but slight signs of fatigue; only rarely is he unable to resume work.
It is noteworthy that some workmen are extraordinarily susceptible to brass-founders’ ague, and are attacked again and again, while others remain completely immune, so that idiosyncrasy and immunity both play a part. Workmen who are susceptible to the disease, yet without marked disposition (idiosyncrasy) towards it, can become acclimatised to the poison. Lehmann has succeeded in artificially producing an attack in a brass-caster who was highly susceptible. The symptoms in him were the result of work with pure zinc in a burning condition. The proof, therefore, is clear that brass-founders’ ague is due to zinc, and not, as some authors have supposed, to copper or the simultaneous action of both metals. The symptoms are produced through inhalation of zinc oxide, not zinc fumes.
Lehmann conjectures that brass-founders’ ague may be a secondary fever due to absorption into the system of the remains of cells in the respiratory tract that have been killed by the action of the zinc.
The treatment can only be symptomatic; as the attack is so transient, medical attendance is hardly necessary.
MERCURY, MERCURY COMPOUNDS
Mercury (Hg), on account of its volatility, is classed among industrial poisons. Although boiling at 360° C. it is volatile even at ordinary temperature. Industrial mercurial poisoning is caused by the frequent inhalation of small quantities of vapour, sometimes, but more rarely, of dust containing mercury, and assumes usually a chronic form.
Industrial mercurial poisoning often begins with inflammation of the mucous membrane of the mouth and gums. There is increased flow of saliva, a disagreeable metallic taste in the mouth, and foul breath. This may be limited to a simple inflammation of the gum, or go on to ulceration with falling out of teeth, or even to gangrene of the gum and mucous membrane inside the mouth. Gastric attacks also occur in the early stages; occasionally, however, they are absent.
The main symptoms of chronic mercurial poisoning are nervous and psychical derangement, to which in severe cases are added general disturbance of digestion and loss of strength.
Sometimes, after repeated attacks, more or less severe, a cachectic condition is induced, showing itself in general emaciation, decrease of strength, atrophy of the muscles, anæmia, and disturbed digestion, which—often intensified by some intercurrent disease, such as tuberculosis—lead to death. Slight cases of mercurialism recover, leaving no evil results, if the patient is removed in time from the influence of the poison.
The treatment of chronic mercury poisoning is symptomatic. To allay the inflammation of the mucous membrane of the mouth the patient should use a mouth wash of potassium chlorate and peroxide of hydrogen; the general condition should be raised by strengthening, unstimulating food; for the nervous symptoms baths and electricity should be tried; and for very marked erythism and tremor recourse to narcotics may be necessary.
Industrial mercurial poisoning is produced not only by metallic mercury but also by many compounds, of which industrially the oxides are the most important. Nitrate of mercury (Hg₂(NO₃)₂) comes into account in the treatment of fur. Mercury cyanide (HgCy₂) deserves mention, as small quantities cause mercurial and large quantities cyanogen poisoning.
MANGANESE, MANGANESE COMPOUNDS
Manganese (Mn) or manganese compounds are used industrially in fine powder; continuous absorption of dust containing manganese produces chronic manganese poisoning. Instances of such poisoning are not very numerous; altogether about twenty cases have been described. Recent publications agree in asserting that only the dust rich in manganese protoxide is dangerous.
Industrial manganese poisoning runs its course extraordinarily slowly, and resembles chronic poisoning by other heavy metals, such as lead and mercury, in that nervous and psychical symptoms, rather than digestive, are prominent. Sometimes—but not always—the disease is introduced or accompanied by psychical symptoms, both of excitement and depression (hilarity, laughing, or depression and weeping). In the course of the disease nervous disturbances arise, deafness, tingling, paralysis and paræsthesia, in the arms and legs, giddiness, difficulty of walking, tremor, increased knee-jerks and difficulty in speech. Often at the same time swelling of the lower extremities (œdema) and loss of strength (cachexia, marasmus) come on. Slight cases make a good recovery. An interesting case of illness is described by Jaksch as manganophobia, in which the symptoms were simulated, and were brought on solely by the fear of manganese poisoning.
As regards treatment, electricity, massage, and baths are advocated to allay the nervous symptoms, as in the case of chronic metal poisoning and suitable strengthening food.
CHROMIUM, CHROME COMPOUNDS
Chromium trioxide (CrO₃) dissolves in water, forming chromic acid (H₂CrO₄); of the salts of chromic acid the neutral and acid alkaline salts concern our inquiry. These are normal and acid sodium or potassium chromate (K₂CrO₄ and K₂Cr₂O₇). Chromate of lead (PbCrO₄) can cause lead poisoning.
Poisoning can be produced by dust and by alkaline chromates, the latter, when hot, giving off steam which, as has been proved, contains excessively fine chrome particles. Chrome compounds attack especially the surface of the body, the skin and the mucous membrane.
The bichromate and chromate dust produce ulcers where slight injuries to the skin already exist. The ulcers develop slowly, and have a smooth, heaped-up, undermined edge; deep-seated, they can even pierce to the bone; they heal with great difficulty. Naturally they occur most frequently on the uncovered parts of the body, especially on the arms and hands. Characteristic also is an analogous ulceration attacking the mucous membrane of the nose, from which hardly any chrome worker (especially if brought into contact with chromate dust) is free. Perforation and destruction of the cartilaginous septum of the nose is very common. Ulcers on the mucous membrane at the entrance of the throat (on tonsils and palate or in the larynx) have been occasionally observed.
Absorption of small quantities of chrome compounds into the body are said to cause disturbances of digestion of an inflammatory character, and especially inflammation of the kidneys.
The treatment of chrome ulcers is similar to that of other chronic ulcers. An antidote for industrial chrome poisoning is not known.
OTHER METALS AND METAL COMPOUNDS
Nickel Salts.—Of late years in nickel-plating establishments an eczematous inflammation of the skin has been described affecting first of all the hands, and occasionally spreading over the arms and even the whole body. The skin becomes inflamed, and vesicles appear on the affected part. Some persons are extraordinarily susceptible to this disease, others only become so after having worked for years quite unaffected, and are then obliged to give up their occupation. Probably the action of nickel salts (especially nickel sulphate) used in electrolytic baths causes the disease. But it was in fact traced by several writers to contact with benzene, petroleum, and lime by the workmen. The simultaneous action of these substances upon the skin would no doubt encourage its appearance. The application to the skin of vaseline or cream is recommended. Careful cleanliness and attention to the skin is on the whole by far the most reliable protection.
[Nickel carbonyl (Ni(CO)₄).—Mond, Langer, and Quincke in 1890 discovered that, on passing a current of carbon monoxide over finely divided (pyrophoric) metallic nickel, a gaseous compound of nickel and carbon monoxide was formed. When heated to 150° C. the gas decomposes into its constituents and metallic nickel is deposited.
Nickel carbonyl is a clear, pale straw-coloured liquid, volatilising at room temperature. It has a peculiar soot-like smell detectable when present to the extent of about 1 vol. in 2,000,000, while the Bunsen flame becomes luminous when nickel carbonyl is present in the air to the extent of 1 vol. in 400,000—two facts of great importance in detecting escape of the gas in the manufacture of pure nickel by the Mond process.
Occurrence of poisoning by nickel carbonyl.—At the first introduction of the process about 1902, before the dangerous properties of the gas had been sufficiently recognised, some twenty-five men were poisoned, of whom three died. Poisoning only occurred when, as a result of the breakdown of the automatic working of the plant, hand labour took the place of machinery.
This very rare form of poisoning has been very fully investigated by H. W. Armit (Journ. of Hygiene, 1907, p. 526, and 1908, p. 565). The symptoms in man, he says, were transient headache and giddiness and at times dyspnœa, quickly passing off on removal to fresh air. After from twelve to thirty-six hours the dyspnœa returned, cyanosis appeared, and the temperature began to be raised. Cough with more or less blood-stained sputum appeared on the second day. The pulse rate became increased, but not in proportion to the respiratory rate. The heart remained normal. Delirium of varying types frequently occurred. Death took place in the fatal cases between the fourth and eleventh days. The chief changes found post mortem were hæmorrhages in the lungs, œdema of the lungs, and hæmorrhages in the white matter of the brain, while some doubt exists as to whether any blood changes were present.
Precisely analogous results were found in experiments on animals (rabbits, cats, and dogs).
The points Armit investigated experimentally were (1) Is the carbon monoxide of the compound wholly or partly responsible for the symptoms, or (2), is nickel carbonyl absorbed as such, or (3), is it the nickel of the compound which produces the symptoms? His conclusions are that the poisonous effects of nickel carbonyl are entirely due to the nickel of the compound. The peculiar toxicity is due to the fact that, being introduced in a gaseous form, the nickel is deposited as a slightly soluble compound in a very fine state of subdivision over the immense area of the respiratory surface. Nickel carbonyl when mixed with air cannot be absorbed as such by an animal as it becomes split up into the nickel containing substance (possibly hydrated basic carbonate of nickel) and carbon monoxide before or soon after reaching the alveoli of the lungs. The nickel is dissolved from the respiratory surface by the tissue fluids and is then taken up by the blood. The hæmorrhages found after death follow as the result of fatty degeneration of the vessel walls which is the specific pathological change set up by nickel.]
Copper.—Symptoms which have been described by some writers as chronic industrial copper poisoning are probably due to admixtures of other poisonous metals, especially lead and arsenic. Although some copper workers, especially those careless of cleanliness, exhibit hair and teeth coloured by the action of copper compounds (green tinge on hair and edge of teeth), symptoms of illness traceable to copper are not demonstrable.
Brass-founders’ fever, which by some earlier writers was ascribed to copper or combined copper and zinc action, is traceable to zinc (see Zinc).
Ferro-silicon.—The illnesses due to this are phosphoretted or arseniuretted hydrogen poisoning (see pp. [191] and [197]).
Silver and Silver Compounds.—Gradual absorption of small quantities of a solution of silver may produce industrial argyria, often beginning with the appearance of a black edge to the gums and darkening of the hair and nails, followed by black spots on the skin which in severe cases coalesce, so that the whole or almost the whole surface of the body becomes black and glossy.
Argyria is due to the absorption of silver compounds into the circulation, and subsequent deposition of the reduced silver in the body (liver, kidneys, spinal cord, &c.). The black colouring of the skin is caused by the action of light.
No interference with health worth mentioning is observed.
GROUP: ARSENIC, PHOSPHORUS
The poisons (gradually absorbed) belonging to this group are mainly such as affect metabolism; they impair the processes essential to metabolism (in especial the oxidation processes) and cause severe damage to the cells, through destruction of albumen. The poisons of this group also have a paralysing effect upon the central nervous system.
Generally speaking the effects produced by the poisons of this group vary considerably. Among the arsenic compounds arseniuretted hydrogen, which is supremely a blood poison, must be excluded from the group and included among the blood poisons.
ARSENIC, OXIDES OF ARSENIC
Pure metallic arsenic (As) is considered innocuous. Oxides of arsenic especially are held to be industrial poisons such as arsenic trioxide (As₂O₃), the anhydride of arsenious acid (H₃AsO₃), a white powder, which is known under the name of white arsenic; arsenic acid (H₃AsO₄), which forms crystals easily soluble in water, and the salts of these acids, especially copper arsenite, formerly employed in the production of dyes, and also arsenic chloride (arsenic trichloride, AsCl₃). Arseniuretted hydrogen will be treated separately as it has a completely different poisonous effect from that of the oxidic compounds of arsenic. Arsenic sulphides (realgar, AsS₂, and orpiment, AsS₃) are regarded as innocuous in consequence of their insolubility in a pure state. But it may be remarked that arsenic sulphides (sulphur arsenic ores) which are used industrially, and even metallic arsenic, are to be considered poisonous, as they contain oxidic arsenic compounds in great quantity.
Chronic arsenical poisoning is caused by gradual absorption through the respiratory or digestive tracts of small quantities of the oxidic arsenic compounds either in solution or as dust or fumes.
The disease usually begins with digestive derangement which shows itself in more or less severe gastric and intestinal catarrh (loss of appetite, vomiting and diarrhœa); sometimes there are severe affections of the respiratory tract,—pharyngeal and bronchial catarrhs; often the illness is accompanied by skin affections of various kinds, rashes, pustular eczema, loosening of the nails, abscesses, dark pigmentation of particular parts of the skin, and other symptoms. The nervous symptoms vary much according to the severity of the disease; first of all, deafness and feeling of pins and needles, or loss of sensation (paræsthesia and anæsthesia) of the extremities. Further, rheumatic joint pains, weakness of the extremities and characteristic symptoms of paralysis occur, with accompanying atrophy of the muscles, and gradual loss of energy leading to total incapacity for work. Severe cases end in general exhaustion and loss of strength, with signs of severe injury to the central nervous system, such as epileptic fits, mental hebetude, &c.
PHOSPHORUS
Phosphorus (P) is polymorphic; red (amorphous) phosphorus is innocuous, while white or yellow is poisonous. Phosphorus at various stages of oxidation is little if at all poisonous. White phosphorus is volatile and fumes in the air—the fumes consisting of phosphorus, phosphoric and phosphorous acids.
Chronic industrial phosphorus poisoning is produced by continued inhalation of the fumes of white phosphorus resulting in inflammation of the periosteum of the bone, with which necrosis and formation of new bone are associated. It attacks especially the lower jawbone (ossifying periostitis). The inflammation begins with increased flow of saliva, painful swelling of the gums, which, as it increases, brings about the death of the jawbone (necrosis, phosphorus necrosis). This becomes covered again with newly formed bone substance from the periosteum. The process ends with the formation of a fistula (a passage filled with pus), which discharges outwards, and through which the dead bone (sequestrum) is eventually cast off. Occasionally the process attacks the upper jaw, rarely other bones.
With these characteristic symptoms of phosphorus necrosis, derangement of nutrition together with anæmia, indigestion and bronchial catarrh, may be associated. Further, a general brittleness of the bones (fragilitas ossium) is observed with the result that the long bones of the leg or arm sometimes break at relatively small exertion of force; such cases from Bohemia came lately under my notice.
Some authorities regard caries of the teeth as the pre-disposing cause of phosphorus necrosis; according to this view the carious teeth constitute the means of entrance for the poison. Opposed to this so-called ‘local’ theory is the view that chronic phosphorus poisoning is a ‘general’ one. The truth may lie midway. On the one hand phosphorus necrosis probably arises partly from the general poisonous action of the phosphorus, and on the other from local inflammation which leads to the occurrence of local symptoms. The general symptoms of chronic phosphorus poisoning described above support this view, especially the effect observed on the bones of the skeleton. This view is also strengthened by the fact that workmen with perfectly sound teeth, who had been exposed to phosphorus fumes for many years, were attacked by necrosis only when traumatic inflammation produced by chance injury was set up.
The treatment of phosphorus necrosis is surgical. Formerly the treatment recommended was to wait for formation of new bone and exfoliation of the dead bone (expectant treatment); the necrosed portions of bone were then extracted through the fistula. Recently early operative interference has succeeded in preserving the periosteum which enabled the new bone to form.
Phosphoretted Hydrogen
Industrial poisoning by gaseous phosphoretted hydrogen (PH₃) calls for attention in connection with the preparation and employment of calcium carbide (acetylene) and also of ferro-silicon.
Phosphoretted hydrogen is a dangerous poison. Even 0·025 per cent. in the air is harmful to animals after a time; 0·2 per cent. PH₃ in the air quickly causes death.
The poison produces changes in the lungs, though without injuring the respiratory passages by corrosion, and finally has a paralysing effect upon the central nervous system. It has no effect upon the blood. An autopsy on a person who has died of phosphoretted hydrogen poisoning reveals as a rule no characteristic sign, except centres of inflammation in the lungs.
The symptoms of phosphoretted hydrogen poisoning are—difficulty of breathing, cough, fainting fits, noises in the ears, and nausea; in severe cases coma and death. Slight cases soon recover without after-effects.
GROUP: SULPHURETTED HYDROGEN, CARBON BISULPHIDE, AND CYANOGEN (NERVE POISONS)
In this group are comprised industrial poisons the principal effect of which is upon the nervous system, especially the central nervous system. The chemical composition of the separate members of the group differs much.
SULPHURETTED HYDROGEN
Industrial poisoning by pure sulphuretted hydrogen (SH₂), the well-known colourless, nauseous-smelling gas, occurs comparatively rarely. Poisoning is generally acute, but chronic illness in workers has been traced back to inhalation of the gas.
This poison exerts a paralysing action upon the central nervous system and is slightly irritating to the mucous membranes and respiratory organs.
Its action can be described as follows: When absorbed into the blood union of the poison with the alkaline constituents takes place with formation of an alkaline sulphide. Presence of only slight quantities of sulphuretted hydrogen in the air acts injuriously. Lehmann has shown that about 0·15 to 0·2 per thousand sulphuretted hydrogen is not without effect, and that prolonged inhalation of 0·5 per thousand becomes dangerous. Continued exposure to the poison seems only to increase susceptibility to its action. An almost complete absorption of the whole of the sulphuretted hydrogen present in the air breathed takes place.
Continued inhalation of small quantities of sulphuretted hydrogen produces irritation of the mucous membrane, cough, and lacrymation; headache, giddiness, nausea, and mental dulness soon ensue; occasionally also symptoms of intestinal catarrh follow; if at this stage—or after a longer exposure to the action of a smaller amount—the patient is withdrawn from its further influence, there still continue for some time symptoms of irritation of the mucous membrane (such as inflammation of the conjunctiva and of the respiratory passages).
Further exposure or absorption of greater amounts induces general discomfort and passes on to a second stage of convulsions and delirium.
Inhalation of a large dose of sulphuretted hydrogen causes almost instantaneous death; the affected person falls dead—often without a sound—as if struck by a blow; occasionally a short stage of unconsciousness, with symptoms of suffocation, precede death.
This acute form often occurs, especially in acute sewer gas poisoning. Besides this, a sub-acute form of sewer gas poisoning is recognised which is attributable, in part at least, to the action of sulphuretted hydrogen, the prominent symptoms being irritation of the mucous membranes and of the intestinal canal. In other severe cases symptoms of the central nervous system preponderate (headache, giddiness, and delirium). These forms of poisoning can be caused not only by sulphuretted hydrogen, but also by other poisonous gases which are found in drains or sewers.
As regards treatment, continued inhalation of oxygen, supported by artificial respiration, is often, in serious cases, effective. In severe poisonings also saline injections and bleeding may be advocated. Other symptoms (catarrh, &c.) must be treated symptomatically.
CARBON BISULPHIDE
Pure carbon bisulphide (CS₂) is a colourless, peculiar-smelling liquid which boils at 46° C.
As Lehmann has shown, even 1·5 to 3·0 mg. CS₂ per litre of air produces distress—with acute symptoms of poisoning (congestion, giddiness, sickness, &c.).
Industrial carbon bisulphide poisoning is, however, chronic in nature and induced by continuous inhalation of small quantities of the fumes. To understand the action of carbon bisulphide, its capacity for dissolving fats and fatty substances must be taken into account. Its injurious effect extends to the nerve tissues (central and peripheral nervous system) and the glandular tissues.
Throughout chronic industrial carbon bisulphide poisoning, which has been described fully by Delpech, Laudenheimer, and others, nervous and psychical symptoms predominate, together with severe chronic digestive derangement.
The patient after exposure for some time suffers from violent headache, giddiness, and sickness; he has sensations of cold, pains in the limbs, a feeling of ‘needles and pins,’ and itching in different parts of the body. Gradually a condition of general excitement develops. Sleeplessness, cramps, and palpitation set in. At the same time the nervous system becomes involved—hypersensitiveness, loss of sensation or complete numbness of some parts of the skin, diminution of muscular power, disturbances of movement, twitching, violent trembling, wasting of the muscles, and paralysis; the sight also is sometimes affected. The stage of excitement, in which the patient often becomes strikingly loquacious without cause, passes gradually, as the nervous symptoms develop, into the stage of depression; sometimes this takes weeks and months; excitement and gaiety give place to deep depression; other symptoms appear—weakness of memory, mental dulness, and difficulty in speaking. The powers of sensation become affected, paralysis increases, and digestive disturbances, anæmia, and general loss of strength are manifest. Occasionally definite mental disease (psychosis, mania, melancholia, dementia, &c.) develops.
Certain cases of chronic carbon bisulphide poisoning in indiarubber workers have come under my notice, and some remarks concerning them may be of interest. The characteristic symptoms are essentially as follows: the invalid appears in the consulting-room in a bent position, leaning upon a stick with head and hands shaking. The gait is clumsy (spastic-paralysis) so that the patient ‘steps’ rather than walks. When seated, the tremor ceases to some extent, but in purposive movements increases rapidly, involving the whole body, so that an exact systematic examination becomes impossible, and the invalid sinks back into the chair exhausted and bathed in perspiration. He complains of cold in the extremities. He looks pale; the skin of the upper extremities is totally without feeling, as also is the upper part of the feet; the skin of the head is hypersensitive; the muscular strength of the arms is almost lost; testing the strength brings on marked shaking, followed by a fainting-fit caused by exhaustion. The extremities of the patient are cyanotic (livid); the knee jerks are exaggerated. The patient suffers from indigestion, constipation, headache, and giddiness; he is irritable, and depressed; his memory is weak; mental derangement cannot be proved.
Chronic carbon bisulphide poisoning is rarely fatal. Slight cases end in recovery after more or less long continuance; in severe cases improvement occasionally takes place, but serious nervous disturbance (paralysis, weakness of the muscles, deterioration of intellect) usually persists.
Treatment is symptomatic, aiming especially at relieving the nervous symptoms and improving the state of nutrition. If psychical disturbances are prominent, treatment in an institution is necessary.
CYANOGEN AND CYANOGEN COMPOUNDS (CYANOGEN GAS, PRUSSIC ACID, CYANIDES)
Industrial cyanogen poisoning is not frequent. Cyanogen gas (C₂N₂, existing in small quantities in furnace gas, illuminating gas, and other kinds of gas) and especially hydrocyanic acid (CNH, prussic acid) are considered industrial poisons; the latter is a very unstable, colourless, pungent-smelling liquid, boiling at 27° C. Among the cyanides employed industrially and having an effect similar to that of prussic acid must be mentioned cyanide of potassium and cyanide of sodium (KCN and NaCN), cyanide of silver (AgCN) and cyanide of mercury (Hg[CN]₂).
Cyanogen and cyanogen compounds are extraordinarily powerful poisons. The minimum dose lies, as Lehmann has proved by experiments on animals, at about 0·05 per thousand of hydrocyanic acid in the atmosphere breathed; 1-5 mg. per kg. weight is fatal to animals; to man about 60 mg. would be fatal.
The poisonous action of cyanogen and cyanogen compounds depends upon their power of preventing absorption of oxygen from the blood by the tissues with the result that the venous blood flowing to the heart retains the bright red colour which otherwise only arterial blood exhibits. This effect is due to cessation of the gaseous exchange in the body, and results in tissue suffocation. At the same time these poisons have at first an exciting and then a paralysing effect upon the central nervous system. In severe poisoning the nerve effect is masked by the effect upon the exchange of gases in the blood, since this quickly leads to death.
Most of the cases of industrial poisoning under this heading result from inhalation; absorption of liquid cyanogen compounds through the skin can rarely come into consideration.
If large quantities of hydrocyanic acid have been inhaled, death ensues very quickly. The person affected falls down suddenly, breathes with difficulty, the pulse soon becomes imperceptible, and after a more or less long stage of deep unconsciousness (coma) life becomes extinct.
In slight cases of poisoning the patient feels a sensation of irritation in the throat, giddiness, sickness, and difficulty in breathing; occasionally such disturbances persist for some time.
Some writers have described symptoms in workers manipulating prussic acid and cyanides, which they believe to be due to chronic prussic acid poisoning. Complaint is made of oppression of the chest, throat irritation, giddiness, difficulty in breathing, palpitation, hebetude, exhaustion, and nausea and vomiting; in certain instances the attack, aggravated by exhaustion and weakness, culminates in death. It is a question whether such poisonings are chronic in the true sense of the word. In view of the mode of action of hydrocyanic acid, such cases of sickness should rather be accounted acute or sub-acute poisonings through repeated action of small quantities of the poison.
It may be mentioned that in persons working with alkaline cyanides (especially in electro-plating) skin affections occasionally occur; these are traceable to the caustic effect of alkaline cyanides.
Treatment by oxygen inhalation with simultaneous artificial respiration holds out most prospect of success. This holds good for acute poisoning by the other poisons belonging to this group. Besides this, saline injections and bleeding are recommended, and also the administration of an infusion of sodium thiosulphate solution.
GROUP: ARSENIURETTED HYDROGEN AND CARBONIC OXIDE (BLOOD POISONS)
Included in this group, as in the former one, are substances chemically very different from each other, but of which the action is especially on the blood. Besides this common effect, these substances also produce various other effects, such as local irritation, effect on the nervous system, &c. The industrial blood poisons, which according to their chemical constitution are classed among the aliphatic and the aromatic series of organic compounds, will, for the sake of clearness, be discussed in the following chapters.
ARSENIURETTED HYDROGEN
Acute arseniuretted hydrogen poisoning, produced by inhalation of relatively very small quantities of arseniuretted hydrogen gas (AsH₃) is in most cases industrial in origin. The absorption of an amount corresponding to about 0·01 mg. arsenic suffices to produce severe poisoning symptoms. The poisonous effect results chiefly from action upon the red blood corpuscles, which are dissolved (hæmolysis). Arseniuretted hydrogen is therefore a genuine blood poison. The effect upon the blood, if not immediately fatal to life, is to cause the dissolved blood-colouring matter to pass into the tissues where, though some is deposited, most goes to, and acts injuriously on, the organs, especially the liver, spleen, and kidneys. In cases running at once a fatal course, the impoverishment of the blood caused by the lack of colouring matter necessary to internal respiration produces tissue suffocation, which is therefore the primary cause of death. In cases not immediately fatal, the injury to the functions of the organs alluded to (for instance, cessation of the functions of the kidneys, &c.) may lead to death secondarily.
Symptoms of the disease appear often only some time after the poisoning has set in, and begin with general malaise, sickness, collapse, fainting fits, and difficulty of breathing; after some hours the characteristic signs follow—the urine becomes dark red to black, containing quantities of blood colouring matter and dissolved constituents of the blood, and later also bile colouring matter, so that a coppery jaundice comes on if the illness is prolonged. The region of the liver, spleen, and kidneys is painful. Severe cases often end fatally during the first stage of the illness, more rarely later, with increased difficulty of breathing; sometimes death occurs after a preceding comatose stage marked by convulsions and delirium. In slighter poisoning cases the symptoms abate in a few days and recovery follows.
The treatment of arseniuretted hydrogen poisoning is similar to that adopted in the case of all other blood poisonings: in addition, if possible, direct transfusion of blood from the artery of the giver into the vein of the receiver, liquid nourishment, saline injections, and, above all, prolonged oxygen inhalation.
CARBONIC OXIDE (CO)
Carbonic oxide (CO) is a colourless, odourless gas which frequently causes both acute and, it is said, chronic industrial poisoning.
Carbonic oxide is a very poisonous gas; even as little as 0·5 per thousand in the atmosphere breathed has a poisonous effect; about 2-3 per thousand can be dangerous to life.
Its poisonous effect results from its power of combining with the blood-colouring matter or hæmoglobin to form carboxy-hæmoglobin; the affinity of carbonic oxide for the hæmoglobin of the blood is more than 200 times greater than that of oxygen, so that, however small the amount of carbonic oxide in the air, it is inevitably absorbed by the blood and retained. The blood so altered, assumes a cherry-red colour, is unable to effect the necessary exchange of gases for internal respiration, and in consequence of the lack of oxygen suffocation ensues.
Without doubt, however, carbonic oxide has also an immediate effect upon the central nervous system (first excitation, followed quickly by paralysis). It is maintained also that besides the action upon the hæmoglobin it favours coagulation of the blood through the disintegration of the blood corpuscles. The last-mentioned action is thought to account for the sequelæ of carbonic oxide poisoning, but they can also naturally be accounted for by the direct effect of the poison.
Onset of symptoms is very sudden if a large quantity of pure carbonic oxide is inhaled. The affected person immediately falls down unconscious and succumbs after drawing a few breaths with difficulty.
In less acute cases the illness begins with premonitory symptoms, generally headache, sickness, giddiness, sleepiness, though in cases of fairly rapid absorption these are absent, and are naturally absent also when the poisoning creeps upon the affected persons while asleep, as occasionally happens in cabins, &c., in factories. If the poisoning continues, increasing mental dulness, accompanied by nausea and vomiting, leads sometimes to a short stage of seemingly drunken excitement, which preludes deep unconsciousness during which there is often a convulsive stage, followed by complete loss both of sensation and of reflex action; the breathing becomes shallow and intermittent, the pulse small and irregular, and finally death ensues. Occasionally in the stage of unconsciousness, death is hastened by entrance of vomited matter into the respiratory passages. Bright red patches are seen on the body after death.
If persons affected by severe carbonic oxide poisoning are withdrawn from the poisonous atmosphere after having reached the stage of unconsciousness, they may recover, but often with difficulty; not infrequently—in spite of suitable treatment—death occurs some considerable time later from the symptoms described above. Still, in many cases, under the influence of right treatment, gradual recovery has been brought about, even after long unconsciousness accompanied by repeated convulsions. In the rescued the symptoms described as characteristic of the first stage often continue for at least a day. Further, they are liable to a number of serious after effects, such as severe inflammation of the lungs due to infection by the entrance of vomited matter into the air passages, skin affections (rashes), and especially severe nervous and mental affections. Frequently these develop from centres of softening in the brain or from inflammation of the peripheral nerves (neuritis); occasionally the poisoning may really only be the predisposing cause for the outbreak of an existing psychical disease. It is not our task to enumerate all the extremely varied disturbances which are observed after carbonic acid gas poisoning. Neuralgias and paralyses have been described as associated with the peripheral nerve symptoms over areas supplied by different nerves; various forms of diseases of the brain and spinal cord (poliomyelitis, paralysis, sclerosis, &c.); and finally a series of psychoses (neurasthenia, melancholia, mania, &c.), occasionally passing into dementia and imbecility. Glycosuria (sugar in the urine) has also been noted as a sequela.
Chronic carbonic oxide poisoning, arising from continued inhalation of small quantities of the gas, sets in usually with symptoms similar to those of acute carbonic oxide poisoning; if the worker continues exposed to danger, severe symptoms may arise which point to marked alteration of the blood and later also of the digestion and bodily functions. Under certain circumstances severe nervous and mental affections are said to occur similar to those which we have mentioned as sequelæ of acute carbonic oxide poisoning (convulsions, disturbances of mental activity, symptoms which resemble progressive muscular atrophy, &c.).
In acute carbonic oxide poisoning oxygen inhalation indefatigably continued and supported by artificial respiration is often successful. The serious danger from this form of poisoning renders it very necessary that in all premises where there is risk provision should be made for the administration of oxygen. The sequelæ can of course only be treated symptomatically.
OXYCHLORIDE OF CARBON (PHOSGENE)
Oxychloride of carbon (COCl₂), also called phosgene, is, at the ordinary temperature, a colourless gas with a disagreeable smell. This decomposes in moist air into carbonic oxide, hydrochloric acid, or chlorine, and produces a strongly irritant local effect upon the mucous membranes. Industrial poisoning by phosgene is characterised by great difficulty in breathing and inflammation of the respiratory tract (bronchitis and bloodstained expectoration).
Several cases have been treated successfully by oxygen inhalation.
NICKEL CARBONYL
The effects of nickel carbonyl are described on pp. [186-8].
CARBONIC ACID
Carbonic acid (CO₂), a colourless gas, is heavier than air (specific weight, 1·526), and therefore, wherever it collects, sinks to the ground. Carbonic acid is only very slightly poisonous; about 10 per cent. carbonic acid in the air causes asphyxia. The extinguishing of a candle flame will serve as an indication that the amount of carbonic acid in the atmosphere has reached this point. Cases of industrial carbonic acid asphyxia are sudden; they do not occur frequently.
The gradual action of the gas when mixed with air produces first a tingling sensation on the surface of the body, reddening of the face, irritation of the mucous membrane and the respiratory organs, after which succeed difficulty in breathing, palpitation, fainting, and unconsciousness.
Sudden and fatal poisoning occurs industrially. Upon entering places filled with carbonic acid gas the affected person falls down dead almost immediately. These are cases of asphyxia, in which the lack of oxygen certainly plays the greatest part. If those affected by acute carbonic acid poisoning are removed in time out of the dangerous atmosphere they usually recover quickly.
Oxygen inhalations and artificial respiration are to be applied in severer cases. There are no sequelæ.
GROUP: HYDROCARBONS OF THE ALIPHATIC AND AROMATIC SERIES AND THEIR HALOGEN AND HYDROXYL SUBSTITUTION PRODUCTS
The industrial poisons comprised in this group have as their principal general effect injurious action upon the functions of the central nervous system (paralysis or causing excitation) which is prominent in most of the cases of industrial poisoning caused by these substances. This effect is most marked in the case of the readily volatile (low boiling) hydrocarbons, while those less volatile and boiling at a higher temperature often have collateral effects (such as local irritation). The characteristic poisonous effect caused by the chlorine and hydroxyl-substitution products (chloroform and alcohol group) is also mainly on the central nervous system (narcosis).
HYDROCARBONS OF MINERAL OIL
BENZINE, LIGROINE, PETROLEUM, PARAFFIN, VASELINE
Mineral oil (crude petroleum) has, according to its origin, differing composition. Thus in American mineral oil hydrocarbons of the methane series preponderate; in the Russian, hydrocarbons of the aromatic series. Reference has been made in Part I. to this point, as well as to the separation of crude petroleum into its different fractions.
The injury to health produced by crude petroleum and its derivatives is of two kinds. Direct contact with liquid petroleum and the semi-liquid and solid deposit after distillation (paraffin) cause local injury to the skin. Inhalation of the volatile constituents of raw petroleum causes symptoms affecting mainly the central nervous system. They have moreover a markedly irritating effect upon the mucous membrane of the respiratory organs. These substances clearly exhibit the characteristic we have referred to, namely, that the hydrocarbons boiling at low temperature act as nerve poisons, whereas those boiling at a higher temperature produce a local irritant effect.
The skin affections take the form of inflammation of the hair follicles (acne), eruptions with characteristic formation of vesicles, and pimples and pustules which precede the deep-seated formation of ulcers, abscesses, &c.
In paraffin workers the acne-like skin inflammations are known as ‘paraffin eczema.’ They develop sometimes into cancer of the skin (warty and epitheliomatous growths).
In the general poisoning produced by inhalation of petroleum fumes the effect upon the central nervous system is all the more plainly and clearly marked when the irritant effect of the hydrocarbons boiling at higher temperature is slight or absent; that is, in the case of poisoning which arises solely from industrial products of low boiling hydrocarbons; among these benzine is included.
Acute poisoning from inhalation of benzine fumes begins with headache, sickness, and attacks of giddiness resembling alcoholic intoxication. If very much has been inhaled, the patient quickly becomes unconscious, with occasionally muscular tremors, convulsions, difficulty in breathing, and cyanosis.
In cases of poisoning by inhalation of fumes of crude petroleum, these symptoms may be complicated by coughing, intense inflammation of the mucous membrane of the respiratory organs—congestion, bronchitis, bloodstained expectoration, and inflammation of the lungs. In workers who frequently remain long in an atmosphere filled with benzine fumes, further symptoms of chronic benzine poisoning show themselves—mental hebetude, pains in the limbs, trembling, weakness of the muscles, and other disturbances of the nervous system; in such cases these may really be signs of continued attacks of acute or sub-acute poisoning; many benzine workers are anæmic.
The treatment of acute benzine poisoning consists in oxygen inhalation, with simultaneous artificial respiration. Treatment of chronic derangement of health is symptomatic.
HYDROCARBONS OF THE AROMATIC SERIES
BENZENE AND ITS HOMOLOGUES
Benzene (C₆H₆) is a characteristically smelling (aromatic) liquid which boils at 80·5° C. Acute benzene poisoning, which plays an important part as an industrial poisoning, is caused by inhalation of benzene fumes. The various kinds of benzol used commercially contain, besides benzene, alkyl benzenes, especially toluene (methylbenzene, C₆H₅.CH₃, boiling-point 111° C.); xylene (dimethylbenzene, C₆H₄[CH₃]₂, boiling-point 140° C.); pseudocumene and mesitylene (tri-methylbenzene, C₆H₃[CH₃]₃, boiling-point 169° or 163° C.); the regular presence of thiophene (C₄H₄S, boiling-point 84° C.) in commercial benzol must also be taken into account. Industrial benzol poisoning arises, therefore, as a rule, not from the action of pure benzene vapour, but from fumes which contain a mixture of the compounds mentioned.
The course run by industrial benzol poisoning is often very acute, if large quantities are inhaled—death occurring suddenly, after a short illness with symptoms of vertigo. Gradual inhalation of lesser quantities gives rise to headache, giddiness, malaise, then twitchings appear which develop into convulsions, and lastly unconsciousness. In order to ascertain in what manner the various substances contained in commercial benzol share in the poisonous effect, experimental research seemed to me to be indispensable, especially as published statements so far gave no accurate data.
Two cases of industrial benzol poisoning have given rise to close experimental research upon the poisonous nature of benzene.
Lewin undertook experiments on animals; which he confined under bells and caused to inhale fumes of chemically pure and impure benzene. He mentions that even at comparatively low concentration poisoning results, and indeed more readily and certainly from the action of impure than pure benzene. Lewin found that when air was made to flow slowly first through benzene and then into the bell, symptoms of paralysis, convulsions, and unconsciousness showed themselves in from four to six minutes. After-effects by this means could not be observed. Lewin maintains, however, that in man even slight acute action of benzene can be followed by after-effects (giddiness, sickness, headache, distress in breathing, and oppression of the heart).
Santesson made researches upon the poisonous action of benzene in connection with occurrence of certain cases of poisoning through ‘impure benzol’ (coal-tar benzene) in a rubber tyre factory. In the factory mentioned nine young women were poisoned, of whom four died. The symptoms shown were lassitude, anæmia, giddiness, headache, vomiting, and fever. Post mortem, hæmorrhages and fatty degeneration of the endothelium of the bloodvessels and various organs were found. Experimental research showed that commercial benzol and chemically pure benzene had the same effect. Santesson did not succeed in his experiments on animals in producing chronic poisoning by inhalation of benzine and of benzene fumes (which two completely different poisons he does not distinguish strictly from each other, as is the case, unfortunately, with many other writers). My experimental researches upon the poisonous effect of pure benzene, pure toluene, cumene, thiophene, and the most important kinds of commercial benzol gave the following results:
For rabbits the limit of toxicity is a proportion of 0·015 to 0·016 per thousand pure benzene in the air, that is 0·015 to 0·016 c.c. benzene vapour per litre of air.
A concentration of 0·056-0·057 per thousand pure benzene in the air causes in rabbits at once—after one minute—twitching of the muscles; after eight minutes, convulsions; after ten minutes, deep narcosis; and after twenty-five minutes, coma. If the animal is taken out of the bell in time, even if it has shown marked symptoms, it recovers very quickly (in two to ten minutes) without manifesting any after effects. Even in animals repeatedly exposed to the poison sequelæ were not observed.
Dogs are somewhat more susceptible to pure benzene than rabbits; 0·024 per thousand causes after ten minutes severe convulsions, which after twenty minutes become continuous; 0·042 per thousand kills after twenty minutes (sudden death in a state of tetanus).
Cats are less sensitive than dogs and more sensitive than rabbits; 0·03-0·04 per thousand causes after ten minutes attacks of cramp and, after twenty minutes, convulsions; 0·05 per thousand at once brings on poisoning symptoms. As regards the character of the symptoms (cramps, convulsions, quick recovery, no after effects) the above statements apply to all three kinds of animals (rabbit, dog, and cat).
Chloral hydrate completely checks the convulsions and enables animals to tolerate higher concentrations of benzene for a longer time.
Benzene is thus to be counted among nerve irritant poisons. The convulsions are probably provoked by excitement of the motor centres in the brain.
In view of the fact that thiophene in a concentration of 0·03-0·05 per thousand in the air was borne by animals for an hour without producing any symptoms of poisoning, the proportion of thiophene in commercial benzol must be looked upon as practically non-injurious.
The so-called 90 benzol—a commercial benzol of which 90 per cent. distils at 100° C.—has naturally a somewhat weaker action, although, in respect of the poisoning symptoms produced, it is similar to that of pure benzene.
Pure toluene (boiling-point 111° C.) and purified toluol (commercial product, boiling-point 109°-112° C.) produce, when inhaled, gradually increasing narcosis in the three kinds of animals referred to; they produce no symptoms of convulsions or spasms.
After the animals have been taken out of the bell, recovery is not so rapid as after benzine inhalation, but takes from half an hour to one hour. In rabbits and cats 0·046-0·05 per thousand produces after fifteen minutes staggering and paresis; after thirty minutes deep narcosis. The dog is again somewhat more susceptible, as little as 0·034 per thousand causing these symptoms in the same time.
‘Purified toluol’ (commercial product) acts somewhat less rapidly than pure toluene, but this small difference in effect need hardly be considered.
Other poisons were also investigated:—
Solvent naphtha I, a commercial product, of which 90 per cent. comes over at 160° C.; it contains little toluene, chiefly xylene, pseudocumene, and cumene.
Solvent naphtha II, of which 90 per cent. comes over at 175° C, it contains besides xylene, chiefly pseudocumene, mesitylene, cumene, &c.
The fumes of solvent naphtha I cause, when inhaled by rabbits, dogs, and cats, gradual narcosis, although not nearly so quickly as toluene at similar concentrations; recovery usually takes over an hour after the deeply narcotised animals have been removed from the bell. Rabbits and cats are affected in about equal degree. The dog is the more sensitive. Rabbits and cats can tolerate about 0·012-0·013 per thousand of the fumes of solvent naphtha I in the atmosphere for a long time without any symptoms. Only after breathing for fifty minutes air containing 0·0536 per thousand do they become narcotised. In the dog 0·036 per thousand causes narcosis only after thirty minutes.
With the fumes of solvent naphtha II I could not affect rabbits at all. The cat also, in spite of long inhalation of the heavy fumes, showed no marked symptoms of poisoning. In the dog gradual narcosis came about only after an hour’s inhalation of 0·048 per thousand.
The fumes of pure xylene caused narcosis in rabbits after forty minutes’ inhalation of 0·05 per thousand in the atmosphere; after being taken out of the bell the animals recovered slowly (after half an hour to one hour).
Cumene causes no symptoms after one hour’s inhalation in a concentration of 0·06 to 0·07 per thousand. This explains the effects of solvent naphtha I (in which xylene preponderates) and solvent naphtha II (in which pseudocumene, cumene, &c., preponderate). After effects were not observed.
Benzol and toluol fumes, and particularly those of solvent naphtha, exercise a distinctly irritant effect upon the mucous membrane, which, however, passes off without after effects.
Pure benzene, therefore, proved the most poisonous of the substances under investigation. When inhaled its effect (convulsions, with quick recovery) differs essentially from that of toluene, solvent naphtha, xylene, and cumene (gradual narcosis, slow recovery). The fumes of the various kinds of commercial benzol (solvent naphtha) boiling at a higher temperature are practically non-poisonous (solvent naphtha II). Pure benzene fumes are, however poisonous, even in very small quantities in the air. The limit for animals lies at 0·015-0·016 per thousand.
Lehmann has shown in a recent work that man, exposed to a mixture of benzene and air, absorbs 80 per cent. of the benzene.
Treatment of acute industrial benzene poisoning consists in severe cases of artificial respiration, with simultaneous administration of oxygen; in slight cases it is sufficient to bring the patient into fresh air.
Naphthalene.—Naphthalene, which is insoluble in water, has irritant effect upon the mucous membrane and upon the skin when brought into contact with it.
Long continuance in an atmosphere containing naphthalene as dust or fumes causes headache, nausea, giddiness, &c.
HALOGEN SUBSTITUTION PRODUCTS
ALIPHATIC SERIES (NARCOTIC POISONS)
The halogen substitution products of the aliphatic series are not of much account as industrial poisons. They have generally a narcotic effect, that is, a paralysing effect upon the central nervous system, usually preceded by a short stage of excitement. This effect shows itself typically on inhalation of chloroform (methanetrichloride, CHCl₃), which however plays no part as an industrial poison. The narcotic effect of the other alkyl chlorides is less than that of chloroform. With carbon tetrachloride (CCl₄) the narcotic effect is only half that of chloroform; it causes, however, a more violent excitation; inhaling the fumes brings on nausea, coughing, sickness, headache, &c.
Methylchloride (CH₃Cl) has a less narcotising effect. On the other hand it has a stronger local irritant action, which is indeed present also in chloroform, though not so apparent. This gas, as is well known, is used as a local anæsthetic in medicine.
Pure methylene chloride (CH₂Cl₂) similarly is much less powerful than chloroform. Severe poisoning, alleged to have resulted from methylene chloride was caused by a mixture, called indeed methylene chloride, but composed of methylalcohol and chloroform.
Of the remaining halogen substitution products of methane, methyl bromide (CH₃Br) and methyl iodide (CH₃I) have given rise to industrial poisoning.
These poisons also act in the same way as the alkyl chlorides, but the excitement accompanying the narcosis is more marked—so far as the scanty observations allow conclusions to be drawn. The symptoms first show themselves in sickness, giddiness, hebetude, slowing of respiratory movements and of the heart’s action; convulsions or delirium ensue.
Treatment consists in artificial respiration or promotion of breathing by a plentiful supply of fresh air or oxygen; in pronounced narcosis stimulating remedies should be applied.
BENZENE SERIES
Chlorobenzene, and nitro- and dinitro-chlorobenzene and benzoylchloride, have given rise to industrial poisoning.
To chlorobenzene similar action is attributed as to benzene (headache, fainting, rapid breathing, cyanosis); changes in the blood (methæmoglobin formation) have also been observed.
Nitro- and dinitro-chlorobenzene are active poisons; the effect corresponds in general to that of nitro- and dinitrobenzene, but in addition the fumes or dust have markedly irritant action on the skin (dermatitis).
Benzoylchloride (C₆H₅COCl), a colourless, pungent-smelling liquid, produces a violently irritant effect upon the mucous membrane, decomposing into hydrochloric acid and benzoic acid.
Treatment is analogous to that of benzene poisoning, and in cases of benzoyl chloride poisoning to that by hydrochloric acid.
It may be mentioned that chlorine rash is attributed to the action of chlorinated tar products (chlorobenzene compounds).
HYDROXYL SUBSTITUTION PRODUCTS
FATTY SERIES (ALCOHOLS)
The hydroxyl substitution products of the fatty series belong mainly to the narcotic poisons; the greater the molecular weight of the alcohol, the more marked is usually the narcotic effect. According to this propylalcohol is eighteen times as poisonous as ethylalcohol; butylalcohol and amylalcohol have from 36 to 120 times as great a narcotic effect as methylalcohol.
Methylalcohol (wood spirit, CH₃OH) plays relatively the greatest part among alcohols as an industrial poison, because it is employed as a means of denaturing spirit. Its poisonous nature is relatively great, being very persistent. Industrial poisoning by methylalcohol is due to inhalation of the vapour and is rarely of a severe nature. The fumes have a strongly irritant effect upon the mucous membrane, giving rise to throat irritation, cough, hoarseness, and in severe cases bronchitis and inflammation of the conjunctiva of the eye. In addition inhalation of methylalcohol vapour causes headache, giddiness, nausea (inclination to vomit), and occasionally also twitchings and tremor.
The higher alcohols (propyl-, butyl-, amyl-alcohol, C₃H₇.OH, C₄H₉.OH, and C₅H₁₁.OH) occur in fusel oil. They cause but slight (if any) industrial poisoning. Cases of more severe industrial poisoning through amylalcohol fumes have been described (in factories for smokeless powder), with symptoms of sickness, headache, giddiness, with fatal issue in some cases, preceded by severe nervous symptoms (convulsions or delirium).
Beyond speedy removal out of the dangerous atmosphere, probably no special treatment is needed in these cases of industrial poisoning from alcoholic vapour.
GROUP: NITRO AND AMIDO COMPOUNDS OF THE ALIPHATIC AND AROMATIC SERIES (BLOOD POISONS WHICH FORM METHÆMOGLOBIN)
Characteristic of the nitro and amido compounds of the aliphatic and aromatic series of the organic substances is their action upon the blood. The normal oxyhæmoglobin (blood-colouring matter) is changed into methæmoglobin, with which the oxygen is so firmly combined that the internal exchange of gases necessary to life becomes impossible. Methæmoglobin has a dark chocolate-brown colour and a clearly defined characteristic spectrum.
Of the poisons belonging to this group several are important. In so far as these substances are volatile—and this is generally the case with those causing industrial poisoning—effects are due to inhalation of fumes, but it is proved that the poisons of this group in liquid form can be absorbed by the intact skin, and this channel of absorption is characteristic of industrial poisoning. Severe poisoning results especially from wetting the skin by spilling on the clothes, &c.
The grey-blue discoloration of the mucous membrane, especially of the lips, is characteristic; sometimes also the skin is altered in colour. This discoloration is often noticed by others before the patient feels unwell. Soon the person affected has general nausea, vomiting, headache, giddiness, severe nervous symptoms, feeling of anxiety, and difficulty of breathing; in severe cases unconsciousness comes on, and death occurs with increasing cyanosis (lividity).
Treatment is naturally that which has been emphasised in the introductory words to Part II, which hold for all blood poisonings. In mild cases oxygen treatment has given good results. In all factories where such poisoning can occur provision should be made for immediate oxygen treatment. Besides this, the workers must be adequately instructed as to the danger and symptoms of poisoning, especially of the characteristic premonitory skin discoloration, in order to be able to assist their fellows.
NITROCOMPOUNDS
ALIPHATIC SERIES
Nitro-glycerin (triple nitric acid ester of glycerin, C₃H₅.[NO₃]₃), the well-known oily explosive liquid, has also an irritant local effect. When absorbed into the body, in addition to methæmoglobin formation, it causes dilatation of the bloodvessels, slowing of the respiration and heart’s action, and attacks of suffocation. The general remarks upon this group apply here, but symptoms referable to central paralysis occur as the methæmoglobin formation is slow. Industrial poisoning arises through inhalation of gases containing nitro-glycerin and also by absorption through the skin. Statements as to its poisonous nature are very varied. Under certain conditions moistening the skin with small quantities of nitro-glycerin suffices to produce symptoms. Probably the susceptibility of different persons varies greatly.
Amylnitrite (nitric acid amyl ester, C₅H₁₁NO₂), a characteristically smelling liquid, acts similarly. The fumes of amylnitrite, even when inhaled in small quantities, cause marked dilatation of the bloodvessels, through paralysis of the muscular walls of the bloodvessels, thus causing marked flushing of the face; the pulse becomes quick, then weak and slow.
NITRO AND AMIDO COMPOUNDS
AROMATIC SERIES
The substances of this group are important.
Nitrobenzene (C₆H₅NO₂, named oil of mirbane), a yellowish liquid of characteristic smell, induces especially the formation of methæmoglobin in the blood; the effect upon the central nervous system (first excitation, then depression) is often absent. The description of the disease in general in the introductory words of this whole group is characteristic. Occasionally signs of asphyxia show themselves; sometimes there are twitchings, disturbance of the power of sensation, and convulsions; early discoloration of the mucous membrane and the skin, which assume a blue to grey-black colour, is characteristic.
Chronic poisoning is also attributed to nitrobenzene, showing itself in lassitude, headache, malaise, giddiness, and other disturbances of the nervous system.
Nitrotoluene (C₆H₄CH₃NO₂), of which the ortho-compound acts most powerfully, and also nitroxylene (C₆H₃[CH₃]₂NO₂) have similar but less marked effect.
The dinitrobenzenes (C₆H₄[NO₂]₂) are stable bodies. Meta-dinitrobenzene inhaled as dust or otherwise, can produce marked poisoning symptoms essentially the same as those described. Especially characteristic is the early dark discoloration of the skin.
Symptoms resembling nitrobenzene poisoning in general are caused by nitrophenols (C₆H₄.OH.NO₂), of which paranitrophenol is the most toxic; also by dinitrophenols (C₆H₃[NO₂]₂OH), solid crystalline substances which melt at different temperatures, and the mono- and di-nitrochlorobenzenes (C₆H₄.Cl.NO₂ and C₆H₃.Cl[NO₂]₂). In cases of industrial poisoning by dinitrophenol, observed by Leymann, the workers were taken suddenly ill, with symptoms of collapse, pains in the chest, vomiting, distress of breathing, rapid pulse, and convulsions, and died within a few hours. At the autopsy a yellow substance was found with picric acid reaction which appeared to be di- or tri-nitrophenol. In other cases, some fatal, of industrial nitrochlorobenzene poisoning, also observed by Leymann, the typical grey-blue discoloration of the skin was obvious, and the chocolate-brown colour of the blood produced by methæmoglobin.
Trinitrophenol (picric acid, C₆H₂[NO₂]₃OH) is a yellow crystalline compound with bitter taste; poisoning by this substance exhibits clearly strong local irritant action (upon skin, mucous membrane, and intestinal canal, and especially upon the kidneys), besides effect on the blood and central nervous system. Prolonged action of picric acid upon the skin causes inflammation. Absorption of picric acid dust causes inflammation of the mucous membrane of the respiratory passages and symptoms of gastric and intestinal catarrh as well as inflammation of the kidneys.
A jaundice-like discoloration of the skin and darkening of the urine are also characteristic; sometimes picric acid poisoning produces a rash resembling that of measles and scarlet fever.
Nitronaphthalene (C₁₀H₇[NO₂]) and nitronaphthol (C₁₀H₆.NO₂.OH) in addition to methæmoglobin formation have an irritant action. It is stated also that dulness of the cornea is produced.
Azobenzenes also, which are to be considered as intermediate between nitrobenzene and aniline, form methæmoglobin (azobenzene, C₆H₅N = NH₅C₆).
Aniline (amidobenzene, C₆H₅.NH₂), a colourless, oily liquid of aromatic smell, has only slight local irritant effect. In the frequent cases of industrial poisoning by ‘aniline oil’ or aniline hydrochloride, in which the aniline enters through the skin or is inhaled in the form of fume, there appear the typical symptoms common to this group, of the action upon the blood through methæmoglobin formation: headache, weakness, cyanosis, difficulty in breathing, &c., to which are added nervous symptoms such as convulsions and psychical disturbance, although these play a subordinate part in industrial poisoning. In severe cases the typical symptoms of air hunger are shown. Occasionally recovery only takes place gradually, and signs of irritation of the kidneys and inflammation of the urinary organs are seen. These symptoms occur only rarely in acute industrial poisoning, but are, however, in so far worthy of notice because of the frequent occurrence of tumours in the bladder among aniline workers. It is possible that here the irritant action of the urine which contains aniline plays a part. The tumours in the bladder operated upon, in some cases with success, were many of them non-malignant (papillomata), but some were carcinomata (cancerous new growths) running a malignant course, and recurring after operation. In the urine the aniline combines with sulphuric acid, and is partly excreted as paramidophenol sulphuric acid.
The treatment of aniline poisoning is the same as that for all the poisons of this group. In view of the occurrence of tumours of the bladder in aniline workers, they should be instructed to seek medical aid on the first indications of trouble, so that a careful cystoscopic examination may be made.
Toluidine (C₆H₄.CH₃.NH₂), which is mixed with aniline for industrial use, produces the same symptoms with marked irritation of the renal organs.
Of the nitroanilines (C₆H₄.NH₂.NO₂) paranitroaniline is the most poisonous. Characteristic of the action of this compound is methæmoglobin formation, central paralysis and paralysis of the heart’s action.
Of the benzenediamines, paraphenylene diamine (C₆H₄[NH₂]₂) may be regarded as an industrial poison. The irritant action of this substance is prominent; it induces skin affections, inflammation of the mucous membranes, more especially of the respiratory organs, and sometimes inflammation of the kidneys. They have been noted in workers using ursol as a dye; here, doubtless, the action of diimine (C₆H₄.NH.NH.) must be taken into account, which arises as an intermediate product and exercises a markedly irritant action. Further, the general effect of paraphenylene diamine is an irritant one upon the central nervous system.
APPENDIX
TURPENTINE, PYRIDINE BASES, ALKALOIDS
Turpentine oil..—Turpentine oil is a peculiar-smelling, colourless liquid of the composition C₁₀H₁₆; different reactions show that turpentine oil contains the aromatic nucleus (cymene). It is used in the manufacture of varnish, and thus can cause industrial poisoning by inhalation of fumes. Even from 3 to 4 mg. of vapour of turpentine oil per litre of air brings on severe symptoms. Turpentine oil acts as a local irritant, and when absorbed into the system has an exciting effect upon the central nervous system. Inhalation of large quantities of turpentine vapour cause rapid breathing, palpitation, giddiness, stupor, convulsions, and other nervous disturbances, pains in the chest, bronchitis, and inflammation of the kidneys. The last-mentioned symptom also arises from the chronic action of turpentine vapours.
Pyridine.—Pyridine (C₅H₅N), a colourless liquid of peculiar odour, is employed as well as methylalcohol in denaturing alcohol. The disturbance of health observed in workers occupied with the denatured spirit are probably mainly due to the inhalation of fumes of methylalcohol. Pyridine is comparatively innocuous. Eczema, from which persons suffer who come into contact with denatured spirit, is ascribed to the action of pyridine. Larger doses produce a paralysing effect, but this need not be considered in its industrial use.
Nicotine, tobacco.—According to various published statements, effects among tobacco factory workers are attributed to the nicotine contained in tobacco dust and to the aroma which fills the air. Nicotine in large doses has at first an exciting followed by a paralysing effect upon the central nervous system; it causes moreover contraction of the unstriped muscles and has a local irritant effect.
The symptoms of illness ascribed to nicotine are: conjunctivitis, catarrh of the air passages, palpitation, headache, want of appetite, and, particularly, tendency to abortion and excessive menstruation. Severe industrial poisoning due to nicotine has only been observed in workers who chewed tobacco leaves.
Poisonous wood.—The symptoms of disease noticed in workers who manipulate certain kinds of wood are attributed by some writers to the presence of alkaloids. Such knowledge as we have of the illness due to them—they are evidently of the nature of poisoning—is referred to at the end of Part I.
PART III
PREVENTIVE MEASURES AGAINST INDUSTRIAL POISONING
I
GENERAL MEASURES
In discussing preventive measures against industrial poisoning the deductive method from the general to the particular will be followed. The numerous instances of poisoning mentioned in Part I afford a practical basis on which to formulate general rules before passing on to describe special measures. Technical details will be omitted, as they must be left to the technical expert whose business it is to draw up the plans as a whole and to modify them according to the requirements of individual cases.
In the effort to control industrial poisoning and disease it is necessary to insist absolutely on the concerted action of all concerned. In this co-operation every one is called who through his knowledge and sphere of activity is in a position to assist.
The medical man comes in with his special knowledge of the action of poisons as toxicologist, as practising physician (especially as works surgeon and doctor of the sick insurance society), and also in an official capacity as appointed surgeon or medical officer of health; the technical expert comes in as engineer, as manager, as foreman, and as factory inspector. But above all the interest and active co-operation of employers and employed are needed as well as the organisations of both. That the workers should understand and co-operate is essential for the success of preventive measures, and subsequently it will be shown in what direction this co-operation is most necessary.
To make possible such co-operation interest must be aroused and suitable information and teaching supplied to the parties concerned. Medical men and practical workers require to receive instruction in industrial hygiene, and teaching on this subject should be arranged for in secondary and technical schools. Medical men and others who, as officials and insurance doctors, are brought constantly into touch with industrial workers should have opportunity—by means of special courses and lectures—to keep pace with advancing knowledge in this direction. Beside these there are, as educative organisations, special Institutes of Industrial Hygiene and special hospitals for treatment of diseases of occupation which bring together the patients and the teaching staff and so facilitate pursuit of knowledge and research. A beginning of this kind has already been made by the Industrial Hygiene Institute, Frankfurt a.-Main, and the hospital for diseases of occupation at Milan, showing that the ideas are attainable. International agencies which unite all circles interested in the subject irrespective of profession or nationality in common interchange of thought and discussion are of great significance for uniform development of needful preventive measures; international congresses, often in connection with exhibitions, have given valuable stimulus and have been the starting-point of permanent international societies, unions, and organisations. The significance for our inquiry of these international efforts will be more closely considered in the following pages.
II
GENERAL CONSIDERATIONS ON SOCIAL AND LEGISLATIVE MEASURES
INTERNATIONAL PREVENTIVE MEASURES, NOTIFICATION OF INDUSTRIAL POISONING, LISTS AND SCHEDULES OF INDUSTRIAL POISONS
Experience and inquiry in the field of industrial poisoning led to a series of demands which, supported as they were by a general movement for the protection of workers, were soon followed by regulations and legislative action. For a long time efforts have been directed to treat industrial disease and poisoning in the same way as has been done in the case of industrial accidents. The question, however, is attended with much greater difficulty. On the other hand, uniform international regulation of questions affecting prevention of disease is called for both on humanitarian and economic grounds.
The idea of international legislation for the protection of workers was first mooted about the year 1870. The possibility and need of such intervention was much discussed and interest in it kept constantly alive, especially in Switzerland, until the organisations of the workers took up the idea. Several attempts failed. In France in 1883 a proposal of the Socialist party aiming at international agreement on the subject of protection of the workers was rejected. In 1885 (in opposition to Hertling) Prince Bismarck expressed himself strongly against the possibility of such international protection. But the stone, once set rolling, could not be stayed. In the years 1886, 1887, and 1888 the French and English trade unions, as well as the Swiss Federal Council, took up the question afresh. These endeavours at last took tangible shape in the first International Conference for the protection of workers held in Berlin in March 1890. This date remains a landmark in the history of the subject, but not until ten years later—1900—did the Congress held in Paris for the international legal protection of workers lead to the establishment of what had been repeatedly urged, namely, creation of an International Bureau. This was inaugurated at Basle in 1901 and forms the headquarters of the National Associations for Labour Legislation called into being in various countries.
This International Association meets regularly in conference, as in Cologne (1902), Berne (1905), Lucerne (1908), Lugano (1910), and Zurich (1912). The questions raised in the International Labour Bureau, which receives financial aid from a number of States, are fully and scientifically discussed with the object of finding a basis on which to bring into agreement the divergent laws of the different countries. A further task of this strictly scientific institution is the collection and publication of literature bearing on the protection of workers in one and another country, distribution of information, and the editing of reports and memoranda. The question of prevention of industrial poisoning has always taken a foremost place in the programme of the International Association and in the agenda of the International Labour Bureau. At its first meeting a resolution was adopted advocating the prohibition of the use of white phosphorus and white lead, and the Labour Bureau in Basle was instructed to take the necessary steps. Special, if not prohibitive, economical considerations foreshadowed difficulties—all the greater because the matter at issue concerned prohibition of articles playing a part in the markets of the world. Just on that account international treatment of such questions is necessary, since a peaceful and orderly solution can only be arrived at on such lines. International effort endeavours here to press with equal weight on the countries competing with one another commercially, so that in the protection of the workers economic adjustment is sought in order that efforts based on humanitarian grounds shall not at the same time cause economic disadvantages, the aim being to produce general welfare and not merely protection of one class at the expense of another.
Through these international agreements between various countries success in the direction aimed at is hopeful, and indeed to a certain extent—as in the phosphorus and lead questions—actually attained. Thus, for example, Germany and Italy were in a position to enforce prohibition of the use of white phosphorus early, while their neighbour Austria, on account of commercial and political considerations and the conditions of the home lucifer match industry, has only recently decided on prohibition.
As international agreement for the protection of workers is advisable on economic grounds, so also is it reasonable and just from purely humanitarian reasons that workers, without reference to civil condition or nationality, should be equally protected. On this point it is proposed to take a vote and to press only for those reforms which are thoroughly sound and recognised as necessary.
The first step in such a comprehensive attack is precise knowledge of the extent and source of origin of the particular forms of industrial poisoning and disease and the collection of reliable statistics. This suggested the obligation to notify such cases to the proper authorities in the same way as is now done in the case of infectious disease. A motion to this effect had already been passed at the Conference of the International Association for Labour Legislation held in Basle, and a request was made to the Labour Bureau to prepare a list of the diseases and poisonings in question. To them we shall refer later, but a schedule is necessary as a basis to work upon. Yet even when this is done there are obviously great difficulties to be overcome in carrying out the requirement of notification when the aim is kept in mind of collecting complete statistical data for controlling the conditions giving rise to industrial disease. The proposal of the International Association seeks to make notification obligatory on the part both of the medical practitioner in attendance and the occupier, and in connection with this to secure the co-operation of the Sick Insurance Society.[D] The proposal to require the appointed surgeons and surgeons of the Insurance Society to notify all cases is hardly feasible in view of their dependent position. Nor can the obligation on the occupiers lead to the desired result because of their lack of medical knowledge and the fact that by notifying they might be forced to act to their own disadvantage. A successful effort in this direction is recorded in Saxony, where lead poisoning was first made a notifiable disease, and later the general duty of notification of industrial poisoning was prescribed by Order dated March 4, 1901.
| Disease and Industry. (1) | Reported Cases.[E] | ||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1912. (2) | 1911. (3) | 1910. (4) | 1909. (5) | 1908. (6) | 1907. (7) | 1906. (8) | 1905. (9) | 1904. (10) | 1903. (11) | 1902. (12) | 1901. (13) | 1900. (14) | |||||||||||||||
| Lead Poisoning | 587 | 44 | 669 | 37 | 505 | 38 | 553 | 30 | 646 | 32 | 578 | 26 | 632 | 33 | 592 | 23 | 597 | 26 | 614 | 19 | 629 | 14 | 863 | 34 | 1058 | 38 | |
| 1. | Smelting of metals | 56 | 7 | 48 | 3 | 34 | 5 | 66 | 5 | 70 | 2 | 28 | 2 | 38 | 1 | 24 | 1 | 33 | 1 | 37 | 2 | 28 | 54 | 3 | 34 | 1 | |
| 2. | Brass works | 5 | 9 | 1 | 7 | 5 | 6 | 9 | 1 | 11 | 5 | 1 | 10 | 1 | 15 | 5 | 6 | 1 | 3 | ||||||||
| 3. | Sheet lead and lead piping | 6 | 12 | 4 | 9 | 2 | 14 | 6 | 7 | 9 | 7 | 11 | 12 | 17 | 17 | 1 | |||||||||||
| 4. | Plumbing and soldering | 35 | 5 | 37 | 2 | 25 | 1 | 28 | 27 | 20 | 2 | 16 | 4 | 24 | 2 | 21 | 3 | 26 | 23 | 1 | 23 | 9 | |||||
| 5. | Printing | 37 | 32 | 2 | 33 | 4 | 21 | 1 | 30 | 2 | 26 | 3 | 16 | 2 | 19 | 4 | 15 | 13 | 2 | 19 | 23 | 1 | 18 | 2 | |||
| 6. | File cutting | 13 | 18 | 2 | 9 | 1 | 8 | 9 | 2 | 10 | 15 | 12 | 20 | 4 | 24 | 2 | 27 | 1 | 46 | 7 | 40 | 3 | |||||
| 7. | Tinning | 15 | 11 | 13 | 17 | 22 | 10 | 25 | 18 | 1 | 14 | 1 | 10 | 14 | 11 | 10 | 5 | ||||||||||
| 8. | White lead | 23 | 41 | 2 | 34 | 1 | 32 | 2 | 79 | 3 | 71 | 108 | 7 | 90 | 116 | 2 | 109 | 2 | 143 | 1 | 189 | 7 | 358 | 6 | |||
| 9. | Red lead | 3 | 13 | 1 | 10 | 10 | 12 | 7 | 6 | 10 | 11 | 6 | 13 | 14 | 19 | ||||||||||||
| 10. | China and earthenware | 80 | 14 | 92 | 6 | 77 | 11 | 58 | 5 | 117 | 12 | 103 | 9 | 107 | 4 | 84 | 3 | 106 | 4 | 97 | 3 | 87 | 4 | 106 | 5 | 200 | 3 |
| 10a. | Litho-transfers | 1 | 1 | 1 | 1 | 1 | 2 | 10 | 5 | 5 | 3 | 3 | 2 | 7 | 10 | ||||||||||||
| 11. | Glass cutting and polishing | 1 | 1 | 5 | — | 4 | 2 | 3 | 1 | 4 | 4 | 1 | 3 | — | 4 | 8 | 2 | 11 | 3 | 7 | |||||||
| 12. | Vitreous Enamelling | 5 | 19 | 1 | 17 | 7 | 7 | 6 | 4 | 2 | 3 | 4 | 3 | 1 | 9 | 11 | |||||||||||
| 13. | Electric accumulators | 38 | 1 | 24 | 1 | 31 | 27 | 2 | 25 | 1 | 21 | 26 | 27 | 1 | 33 | 28 | 16 | 1 | 49 | 1 | 33 | ||||||
| 14. | Paints and colours | 19 | 21 | 17 | 1 | 39 | 2 | 25 | 35 | 1 | 37 | 57 | 1 | 32 | 1 | 39 | 1 | 46 | 56 | 56 | 1 | ||||||
| 15. | Coach building | 84 | 7 | 104 | 5 | 70 | 6 | 95 | 6 | 70 | 3 | 70 | 3 | 85 | 7 | 56 | 3 | 49 | 4 | 74 | 5 | 63 | 1 | 65 | 4 | 70 | 5 |
| 16. | Ship building | 34 | 2 | 36 | 6 | 21 | 2 | 27 | 1 | 15 | 22 | 1 | 26 | 1 | 32 | 2 | 48 | 24 | 1 | 15 | 1 | 28 | 1 | 32 | 2 | ||
| 17. | Paint used in other industries | 48 | 3 | 56 | 1 | 51 | 3 | 42 | 47 | 1 | 49 | 2 | 37 | 3 | 49 | 2 | 27 | 3 | 46 | 1 | 44 | 1 | 61 | 50 | 5 | ||
| 18. | Other industries | 84 | 2 | 88 | 4 | 47 | 3 | 52 | 2 | 78 | 5 | 56 | 2 | 66 | 2 | 70 | 1 | 53 | 3 | 40 | 64 | 89 | 1 | 86 | 4 | ||
| Phosphorus Poisoning | — | — | — | 3 | 1 | 1 | 1 | — | 3 | 1 | 1 | 1 | — | 1 | 2 | 4 | 3 | ||||||||||
| Arsenic Poisoning | 5 | 10 | 1 | 7 | 4 | 23 | 1 | 9 | 2 | 5 | 1 | 5 | 5 | 5 | 12 | 1 | 22 | 3 | |||||||||
| Mercurial Poisoning | 17 | 12 | 10 | 1 | 9 | 10 | 7 | 4 | 8 | 3 | 8 | 8 | 18 | 9 | |||||||||||||
| Anthrax | 47 | 64 | 11 | 51 | 9 | 56 | 12 | 47 | 7 | 58 | 11 | 67 | 22 | 59 | 18 | 50 | 10 | 47 | 12 | 38 | 9 | 39 | 10 | 37 | 7 | ||
| Wool | 31 | 6 | 35 | 10 | 28 | 3 | 28 | 3 | 18 | 3 | 23 | 3 | 24 | 8 | 34 | 12 | 12 | 1 | 20 | 5 | 12 | 2 | 6 | 4 | 9 | 2 | |
| Horsehair | 7 | 8 | 1 | 6 | 1 | 8 | 2 | 10 | 17 | 4 | 10 | 4 | 7 | 1 | 12 | 4 | 7 | 1 | 10 | 2 | 9 | 1 | 12 | 3 | |||
| Handling of hides and skins | 8 | 20 | 14 | 3 | 18 | 6 | 13 | 1 | 12 | 2 | 19 | 7 | 17 | 4 | 18 | 3 | 12 | 1 | 11 | 5 | 20 | 5 | 9 | 1 | |||
| Other industries | 1 | 1 | 3 | 2 | 2 | 1 | 6 | 3 | 6 | 2 | 14 | 3 | 1 | 1 | 8 | 2 | 8 | 5 | 5 | 4 | 7 | 1 | |||||
My own experience does not lead me to expect much in elucidation of industrial diseases from the Sick Insurance Societies. In Austria they make a statistical return as to the causation of illness to the central authorities. I have myself—in my capacity as an official of the State Central Board—examined these in order to try and gain knowledge of the extent of industrial disease in Bohemia. In spite of the returns drawn up by the district surgeon who visits the factories in question, it was impossible for me to obtain a complete picture of the extent of industrial sickness. The reports only give valuable data on which to base action in particular cases, and from this standpoint I do not under-estimate their value. But so far as the expressed wish of the International Association is concerned they appear to fulfil it, inasmuch as for specially dangerous trades special reports are issued, the Austrian law for sick insurance requiring such industries to institute separate sick insurance funds with separate statistics. Hence, under present conditions, I do not see how the duty of notification will be effective. There remains the endeavour to secure insurance and the right to claim compensation for industrial disease in the same way as is provided for accidents. This point was fully discussed at the eighth International Congress for Workmen’s Insurance held in Rome in 1908. There is no valid ground for granting compensation only for sudden disturbance of health arising in the course of employment by accident or acute poisoning, and withholding it in the case of gradual disturbance of health caused equally by the trade, as the effects of such chronic indisposition weigh often no less heavily on the sufferer. Inclusion of industrial disease in the same category as accident insurance, as indeed has been done in France, Switzerland and Great Britain, has, apart from the fact that it is dictated by fairness and humanity, the advantage of removing existing hardship and of solving doubtful cases. Correct statistics, further, would thus be obtainable for the first time, and the employer by insurance would be freed from the legal proceedings now frequently brought against him for injury due to chronic industrial poisoning. And it seems the more right and just course to institute a general scheme of insurance against industrial disease than to have recourse to an Employer’s Liability Act in this or that case, particularly as the question often arises in regard to a disease which develops gradually—In whose employment was the disease contracted?
Clearly in such a scheme of insurance against both accident and industrial disease only specific industrial diseases would be included, i.e. diseases in which the connection with the industry can be clearly established as due to causes inherent in the industry, and traceable to definite materials used. Such diseases as tuberculosis and the effects of dust inhalation (bronchitis, &c.), which as industrial diseases occur only too often, cannot be called specific, because they arise outside the industry and make decision impossible as to whether or not in a particular case the disease owed its origin to the occupation. In order to determine what should be regarded as specific industrial poisons it was deemed necessary to draw up a schedule. For one such list Sommerfeld (in collaboration with Oliver and Putzeys) is responsible, Carozzi of Milan for a second, and Fischer[F] for a third, published in 1910. Those by Sommerfeld and Fischer are constructed in similar fashion—enumeration of (1) the poisonous substance, (2) the industries in which it is made or used, (3) the channel of absorption, and (4) the symptoms produced. Sommerfeld enumerates the poisons in alphabetical order, noting against each the requisite preventive measures, while Fischer adopts a chemical classification, confining himself to general introductory remarks as to prevention.
Sommerfeld proposes to limit notification to poisoning sharply defined as to the symptoms set up, such as lead, phosphorus, mercury, arsenic, chromium, carbonic oxide, aniline, benzene, nitrobenzene, carbon bisulphide, and nitrous fumes. This simplifies the obligation to notify, but does not dissipate the fears expressed above as to the difficulty, because in the present development of the chemical industries new substances involving new danger to the persons handling them are constantly being discovered, and thus there can be no finality as to which industrial poisonings should entitle to compensation. And if recourse were had from time to time to additions of new substances to the schedule, reliance would have to be placed on experience with regard to each substance added, and thus the actual individual who had suffered would not benefit. Fischer, indeed, acknowledges that any schedule must be incomplete, and emphasises the fact that continual additions would be necessary; otherwise it would be better to refrain altogether from publication of a list. Such lists may be valuable guides, but no sure foundation for insurance legislation. The only possible way to do this is to give as far as possible a correct definition of the industrial diseases entitling to compensation and, in isolated cases, to leave the decision to the expert opinion of competent judges.
Extension of workmen’s insurance to cover chronic industrial poisoning is, however, most desirable in the interest of employers and employed, and also of science. The German accident insurance legislation is especially suited to do this, since the trade organisations direct their attention not only to the prevention of accidents but of industrial diseases also.
III
SPECIAL PREVENTIVE MEASURES FOR WORKERS
SELECTION, CHOICE OF TRADE, ALTERNATION OF EMPLOYMENT, MEDICAL CONTROL, SAFETY APPLIANCES, INSTRUCTION AND CO-OPERATION OF WORKERS, CLOTHING, ATTENTION TO CLEANLINESS, FOOD, GENERAL WELFARE
As a practical measure in protection against trade risk selection of those capable of resisting danger has to be considered. It is obviously desirable to select for employment in a dangerous trade persons possessing powers of resistance, because predisposition and resistance to the action of poisons differ markedly in individuals. To some extent such a selection comes of itself, as those who are very susceptible are obliged by repeated attacks to give up the work. The social and physical misery, undeserved loss of employment, illness, and perhaps early death following on this kind of selection might be checked by timely medical examination so as to weed out the unfit. But medical examination prior to admission into a dangerous trade (actually practised in many industries involving risk of poisoning) inflicts hardship on those seeking employment, and recruits the ranks of the unwillingly unemployed. It would be much better were it possible to meet the need of selection by pertinent direction and guidance in choice of calling. There should be insistence in technical schools especially on the dangers inherent in certain industries, school medical examination as to physical qualifications for certain industries, and careful note made of individual suitability in labour bureaus, apprentice agencies, and the like.
Young female workers, naturally less able to resist, should be excluded from work involving risk of poisoning—a principle which has been acted on in the legislation of civilised countries.
Further, workers engaged in industries involving risk should not be exposed to the pernicious influence for too long a time. Hence the hours of employment should be shortened in occupations proved to be injurious to health. An important aid in this respect is alternation of employment. Change of occupation is particularly recommended where the nature of the poisoning of which there is risk is cumulative in action, because in the intervals from the work the system will rid itself of the accumulated store. In this way a number of skilled resistant workers, familiar with the risk and knowing how to meet it, will be maintained. Casual labour works in a vicious circle—increase of fresh workers increases the danger and the number of cases of poisoning, and, vice versa, these augment again the need of change in the personnel, so that the number of cases of poisoning rises very high. Thus the industry itself may be endangered, since its prosperity depends mainly upon the existence of a skilled staff of workers. In dangerous trades, therefore, Hermann Weber’s words, ‘Change of work instead of change of workers,’ have much force.
Periodical medical examination in these industries cannot well be omitted in order to weed out the physically unfit, and to suspend from work those who show early symptoms. Note should be kept of the state of health of the workers, the results of the periodical medical examination, the duration of symptoms, and the treatment of any illness that occurs. Medical supervision presupposes special training and experience in the medical man entrusted with the task.
Further, in some industries in which poisonous materials are used, especially such as set up acute sudden poisoning, there should be a trained staff competent to recognise the first symptoms of poisoning and to render first aid, and having at its disposal adequate means of rescue.
Apart from the rescue appliances generally needed in dangerous trades, stress must be laid on the value of oxygen apparatus as a means of saving life. In addition to what is needed for the sufferer there must be defensive apparatus at hand for the rescuers (breathing helmets, &c.), to facilitate and make safe their rescue work when in a poisonous atmosphere. Without such defensive equipment rescuers should never venture into gas conduits, or into any place where presumably a poisonous atmosphere is to be met with. It hardly requires to be said that in dangerous industries medical aid should be within easy reach; in large works actual medical attendance may be necessary.
In acute as well as in chronic cases of poisoning early medical intervention is advisable. Hence medical aid should be sought on the earliest appearance of symptoms, and the worker, therefore, should know the nature and action of the poison with which he comes into contact. This brings us to the subject of the education of the worker and particularly observance of all those rules and regulations in which his co-operation is necessary. This co-operation of the workers is indispensable; it is the most important condition of effective defence. The best regulations and preventive measures are worthless if the worker does not observe them. He must be taught their aim, the way of using the means of defence; he must be admonished to use them, and, if necessary, compelled to do so. The co-operation of workmen’s organisations in this matter can avail much, since a workman most readily follows the advice of a fellow-worker.
Teaching of the kind suggested can be done in different ways. Apart from lectures and practical courses, concise instructions, either in the form of notices or as illustrated placards, should be posted up in the workrooms or handed in the form of leaflets particularly to the newly employed. Distribution of such leaflets might well be placed as a duty on the employer.
Of preventive measures applying to the individual those are of prime importance which serve to protect the worker, as far as is practicable, from coming into contact with the poison. Protection of this kind is attained by wearing suitable clothing, use of respirators, and careful cleanliness—especially before partaking of food. It cannot be too strongly urged that these precautions are a very potent defence against the danger of industrial poisoning, especially of the chronic forms, and in teaching workers their importance must be insisted on. It is not sufficient merely to put on overalls over the ordinary clothes. The ordinary clothes must be taken off before the commencement of work, and working suits put on, to be taken off again before the principal midday meal and before leaving work. They should be made of smooth, durable, washable material, and be properly washed and dried not less often than once a week. They must be plainly cut without folds or pockets.
Direct handling of the poisonous substances is to be avoided, but where this is necessary impervious gloves may have to be worn, especially in the case of poisons which can be absorbed through, or act injuriously on, the skin. If there is risk of splashing or spilling of poisonous liquids on to the clothes, impermeable or partly impermeable overalls (aprons, &c.) should be worn. The obligation of providing the overalls or working suits falls naturally on the employer in industries where poisonous substances are used, and there is equally obligation on the employee to use the articles provided.
Suitable cloakroom accommodation is essential, by which is meant room not only to change clothes with cupboards or hooks on one side for clothing taken off on commencement of work and on the other the working suits, but also ample washing accommodation. These cupboards should be double, that is, be divided by a partition into two parts, one serving for the ordinary and the other for the working clothes.
Fig. 35.—Aluminium Respirator
Protection of the respiratory organs can to some extent be obtained by so-called respirators worn over the mouth and nose. Often they consist simply of a moist sponge or folds of cloth, or again may be complicated air-proof affairs enclosing mouth and nose, or the whole face like a mask, or even the head like a helmet; they fit close, and the aperture for respired air is provided with filtering material (cotton wool, &c.) placed between two layers of wire gauze. The outer layer of the gauze moves on a hinge, so that the filtering material can be renewed after each time that it has been used. The construction of respirators is extraordinarily varied. One form is illustrated. They must be light, and in order not to obstruct breathing seriously they are often provided with valves—closing during inspiration and opening during exhalation. Generally the respirators in common use do not quite satisfactorily fulfil the conditions required. After a time the pressure becomes irksome, the face becomes hot, breathing more difficult, and discomfort from wearing them unbearable.
Respirators are only to be regarded in the light of secondary aids and for occasional use.
During temporary exposure to an atmosphere charged with poisonous dust the wearing of an efficient apparatus—preferably one protecting the head—is very desirable.
Fig. 36.—Smoke Helmet, Flexible Tubing, and Foot Bellows (Siebe, Gorman & Co.)
Respirators afford no protection, or a very imperfect one, against dangerous gases or fumes. If soaked with an absorbing or neutralising fluid they can scarcely be worn for any length of time.
In an atmosphere charged with poisonous gas recourse should be had either to a smoke helmet with flexible tubing and bellows or to an oxygen breathing apparatus so constructed that the workman carries the necessary supply of oxygen with him in a knapsack on his back. In the latter case oxygen from a compressed cylinder of the gas is conveyed to the breathing mask, so that respiration is independent of the surrounding atmosphere.
Fig. 37.—Diagram of Draeger 1910-11, Pattern H (R. Jacobson)
P Alkali cartridges; K Cooler; C Aspirating pipe; L₁ Purified air; L₂ Expired air.
The mode of working is represented diagrammatically in figs. [37] and [40]. After putting on the helmet, the bag is first filled with fresh air, the air valve is then closed, and the valve of the oxygen cylinder unscrewed so as to permit of the flow of the oxygen which, mixes with the air in the bag, and begins to circulate; the expired air passes through the caustic potash pellets P, which free it of carbonic acid gas, so that, with a fresh supply of oxygen from the cylinder through the pipe C, it is regenerated and made fit for breathing again. The pressure in the cylinder is measured by a manometer, which indicates also when the supply of oxygen gives out.
Fig. 38.—Showing the Potash Cartridge No. 2 with Change Mechanism X; No. 2 Oxygen Cylinder with Spanner V; and on the Left a Hexagonal Socket U, for unscrewing the Locking Nuts of Reserve Cylinders (R. Jacobson)
Fig. 39.—‘Proto’ patent self-contained breathing apparatus (Siebe, Gorman & Co.)
Another apparatus—the ‘Proto’ patent self-contained breathing apparatus (Fleuss-Davis patents)—is also illustrated in [fig. 39]. [Illustration 40] gives a diagrammatic view of the principle upon which it is designed. The instructions for using the ‘Proto’ apparatus are as follows:
The oxygen cylinders (B, B), having been charged with oxygen through the nipple at (H) to a pressure of 120 atmospheres (about 1800 lbs. per square inch), are to be re-attached to the belt as shown, and the reducing valve, with its tubes, &c., is to be connected to the nipple at (H). This supply is sufficient for fully two hours.
Charging the breathing bag.—Put 4 lbs. of stick caustic soda into the bag (D), i.e. 2 lbs. into each compartment, and immediately fasten the mouth of the bag by means of the clamps and wing nuts (O). If the apparatus is not to be used at once, but is to be hung up for use at some future time, the indiarubber plug which is supplied with the apparatus should be tightly fitted into the mouthpiece in order to prevent access of air to the caustic soda, and to preserve it until required for use.
See that the inlet and outlet valves (T and S) and the connection (N) are screwed up tightly.
The small relief valve (K) is only to be opened (by pressing it with the finger) when the bag becomes unduly inflated through excess of oxygen. This may occur from time to time, as the reducing valve is set to deliver more than the wearer actually requires.
Equipment.—The whole apparatus is supported upon a broad belt which is strapped round the body. The bag is also hung by a pair of shoulder braces.
The wearer having put the equipment over his shoulders, fastens the belt and takes the plug out of the mouthpiece. The moment the mouthpiece is put into the mouth or the mask is adjusted, the main valve (H) is to be opened not more than one turn and the necessary supply of oxygen will then flow into the bag. It is advisable to open the by-pass (I) to inflate partially the breathing bag (D) for a start, but this valve should again be screwed up quite tight and not touched again, except in the case of emergency as previously described should the bag become deflated. Breathing will then go on comfortably.
Should the by-pass (I) on the reducing valve (C) get out of order then the wearer should turn on the by-pass (I) from time to time to give himself the necessary quantity of oxygen, but, as stated above, this is only to be done in case of deflation of the bag. The best guide as to the quantity of oxygen to admit in the above circumstances is the degree of inflation of the breathing bag. It will be found to be quite satisfactory if the bag be kept moderately distended.
After using the apparatus.—The caustic soda should at once be thrown away, but if it is neglected and the soda becomes caked, it must be dissolved out with warm water before putting in a fresh supply. Caustic soda will not damage vulcanised indiarubber, but it will damage canvas and leather, and will burn the skin if allowed to remain upon it.
If the apparatus is to be used again at once, it can be recharged with caustic soda at once, but if it is only to be charged ready for use at some future time the indiarubber bag should be thoroughly washed out with warm water and dried inside with a cloth or towel.
When emptying or recharging the rubber bag with caustic soda, it must always be removed from the canvas bag. After use each day, it is advisable to wash the rubber mouthpiece (or mask, as the case may be) with yellow soap and water. This acts as a preservative to the indiarubber.
Every man who is to use the apparatus should have his own mouthpiece and noseclip, or mask, as the case may be, under his own special care, both for sanitary reasons and so that he may shape and adjust the mask to fit himself comfortably and air-tightly, to such an extent that if the outlets are stopped up by the hands while the mask is held in position by its bands no breath can pass in or out.
Fig. 40.—‘Proto’ Patent Self-breathing Apparatus (Siebe, Gorman & Co.)
Fig. 41.—Arrangement of Cloak-room, Washing and Bath Accommodation, and Meal-room in a White Lead Factory
Where poisonous substances giving off dust or fumes are used, regular washing and rinsing the mouth (especially before meals and on leaving) is of great importance. Naturally the washing conveniences (basins, soap, brushes, towels) must be sufficient and suitable, and the workers instructed as to the importance of cleanliness by the foreman. They should be urged to bath in rotation, and time for it should be allowed during working hours.
The taking of meals and use of tobacco in the workrooms must be prohibited. Meal rooms should be so arranged as to be contiguous to the cloakroom and washing accommodation, the worker gaining access to the meal room through the cloakroom and bathroom. The arrangement described is illustrated in [fig. 41]. The meal room serves also the purpose of a sitting-room during intervals of work, and it goes without saying that cloakroom and lavatory accommodation are as necessary in small as in large premises.
Simple lavatory basins of smooth impervious surface fitted with a waste pipe and plug, or tipping basins, are recommended in preference to troughs which can be used by several persons at once. Troughs, however, without a plug, and with jets of warm water, are free from objection.
The douche bath has many advantages for workmen over the slipper bath. The initial cost is comparatively small, so that it can be placed at the disposal of the workers at very small outlay. Maintenance and cleanliness of douche baths are more easily secured than of other kinds, where changing the water and keeping the bath in good order involve time and expense. A dressing-room should form part of the douche or slipper bath equipment. Walls and floors must be impervious and, preferably, lined with smooth tiles or cement. It is better that the shower bath should be under the control of the worker by a chain rather than be set in motion by means of mechanism when trodden upon. The arrangement of baths is illustrated in [fig. 43]. In many large works large bath buildings have been erected. [Fig. 44] is a plan of the splendid bath arrangements at the colour works of Messrs. Lucius, Meister & Brüning of Höchst a.-M.
Fig. 42.—Good Washing and Bath Accommodation in a Lead Smelting Works
Fig. 43.—Washing Trough, Douche Baths, and Clothes Cupboards, Type common on the Continent
Fig. 44a.—Baths in the Höchst Aniline Works (after Grandhomme)
Fig. 44b.—Ground Floor
Fig. 44c.—First Floor. a, c, Baths (slipper and douche) for workmen; b, Washing accommodation for workmen; d, e, Baths for officials; g, Attendant’s quarters; f, Hot air (Turkish) baths; i, Warm water reservoir.
Naturally maintenance of the general health by good nourishing diet is one of the best means of defence against onset of chronic industrial poisoning. Over and over again it has been noticed that ill-fed workers speedily succumb to doses of poison which well-nourished workers can resist. It is not our province here to discuss fully the diet of a working-class population. We merely state that it is a matter of vital importance to those employed in dangerous trades. The question of a suitable drink for workers to take the place of alcohol calls for special attention, as, when complicated with alcoholism, both acute and chronic poisonings entail more serious results than they otherwise would do. Over-indulgence in alcohol, owing to its effect on the kidneys, liver, digestion, nervous system, and power of assimilation generally, requires to be checked in every way possible. Apart from good drinking water, milk, coffee, tea, fruit juices and the like, are excellent. Milk is especially recommended, and should be supplied gratis to workers in dangerous trades, notably where there is risk of lead poisoning.
Lastly, other features such as games and exercise in the open air, which help to strengthen bodily health, must not be forgotten. In this connection much good work has already been done by employers’ and workers’ organisations.
IV
GENERAL REMARKS ON PREVENTIVE MEASURES
GENERAL PRINCIPLES, SUBSTITUTES FOR DANGEROUS MATERIALS, CLEANLINESS OF WORKROOMS, CUBIC SPACE, VENTILATION, REMOVAL OF DUST AND FUMES
Preventive measures against industrial poisoning aim at an unattainable goal of so arranging industrial processes that employment of poisonous substances would be wholly avoided. Such an ideal must be aimed at wherever practicable. Prohibition of direct handling of poisonous substances is also sometimes demanded, which presupposes (although it is not always the case) that this is unnecessary or can be made unnecessary by suitable mechanical appliances. We have to be contented, therefore, for the most part, with removal of injurious dust and fumes as quickly as possible at the point where they are produced, and regulations for the protection of workers from industrial poisoning deal mainly with the question of the prevention of air contamination and removal of contaminated air. Substitution of non-injurious for injurious processes is only possible in so far as use of the harmless process gives technically as good results as the other. If such a substitute can be found let it be striven for. Mention has already been made of international prohibition of certain substances, and attention has been drawn to economical considerations affecting this point.
Prohibition obviously may paralyse branches of industry and hit heavily both employers and employed. The skilled trained workers are just the ones to suffer, since they are no longer in a position to take up another equally remunerative trade.
Judgment has to be exercised before enforcing new regulations in order that good and not harm may follow. If a satisfactory substitute be discovered for methods of work injurious to health, then ways and means will be found to make the alteration in the process economically possible. It may, however, demand sacrifice on the part of employers and employed, but the progress is worth the sacrifice.
The following are instances of substitution of safe processes for those involving risk: generation of dust can sometimes be avoided by a ‘wet’ method (watering of white lead chambers, grinding pulp lead with oil, damping of smelting mixtures, &c.); the nitrate of silver and ammonia process has replaced the tin and mercury amalgam used in silvering of mirrors; electroplating instead of water gilding (coating objects with mercury amalgam and subsequently volatilising the mercury); enamelling with leadless instead of lead enamels; use of air instead of mercury pumps in producing the vacuum in incandescent electric lamps.
Dealing further with the sanitation of the factory and workshop after personal cleanliness, the next most important measure is cleanliness of the workroom and purity of the air. Workrooms should be light and lofty; and have floors constructed of smooth impervious material easily kept clean. The walls should be lime-washed or painted with a white oil paint. Angles and corners which can harbour dirt should be rounded. Cleansing requires to be done as carefully and as often as possible, preferably by washing down or by a vacuum cleaner. Saturation of the floor with dust oil is recommended by some authorities in trades where poisonous dust is developed and is permitted as an alternative to the methods described. I refrain from expressing an opinion on this method of laying dust, since by adoption of the practice insistence on the need for removal of the poisonous material from the workrooms loses its force—a thing, in my opinion, to be deprecated.
The necessity of keeping the atmosphere of workrooms pure and fresh makes it essential that there should be sufficient cubic space per person and that proper circulation of the air should be maintained. The minimum amount of cubic space legally fixed in many countries—10-15 cubic metres—is a minimum and should be greatly exceeded where possible. Natural ventilation which is dependent upon windows, porosity of building materials, cracks in the floors, &c., fails when, as is desirable for purposes of cleanliness, walls and floors are made of smooth impermeable material, and natural ventilation will rarely supply the requisite cubic feet of fresh air quickly enough. Ordinarily, under conditions of natural ventilation, the air in a workroom is renewed in from one to two hours. Artificial ventilation therefore becomes imperative. Natural ventilation by opening windows and doors can only be practised in intervals of work and as a rule only in small workrooms. During work time the draught and reduction of temperature so caused produce discomfort.
Artificial ventilation is effected by special openings and ducts placed at some suitable spot in the room to be ventilated and arranged so that either fresh air is introduced or air extracted from the room. The first method is called propulsion, the latter exhaust ventilation. Various agencies will produce a draught in the ventilating ducts, namely, difference of temperature between the outside and inside air, which can be artificially strengthened (a) by utilising the action of the wind, (b) by heating the air in the exhaust duct, (c) by heating apparatus, and (d) by mechanical power (use of fans).
Where advantage is taken of the action of the wind the exit to the ventilating duct must be fitted with a cowl.
The draught in pipes is materially increased if they are led into furnace flues or chimneys; in certain cases there is advantage in constructing perpendicular ventilating shafts in the building extending above the roof and fitted with cowls. Combination of heating and ventilation is very effective.
Fig. 45.—Steam Injector (after Körting), showing steam injector and air entry
In workrooms, however, where there is danger of poisoning by far the most effective method of ventilation is by means of fans driven by mechanical power. All the means for securing artificial ventilation hitherto mentioned depend on a number of factors (wind, difference of temperature, &c.), the influence of which is not always in the direction desired. Exact regulation, however, is possible by fans, and the quantity of air introduced or extracted can be accurately calculated beforehand in planning the ventilation. In drawing up such a plan, detailing the arrangement, proportions of the main and branch ducts, expenditure of power, &c., a ventilating engineer should be consulted, as it is his business to deal with complicated problems of ventilation depending entirely for success on the design of the ventilation.
Injectors are usually only employed for special technical or economical reasons. A jet of steam or compressed air which acts on the injector creates a partial vacuum and so produces a powerful exhaust behind. [Fig. 45] shows the mechanism of an injector. They are used for exhausting acid fumes which would corrode metal fans and pipes, and for explosive dust mixtures where fans are inadmissible.
Fig. 46.—Propeller Fan coupled to Electromotor (Davidson & Co., Ltd.)
In the industries described in this book fans are most commonly used. These are, in the main, wheels with two or more wing-shaped flattened blades. Some are encased, others are open and fitted by means of annular frames in the ducts according to the intended effect and kind of fan. Fans are of two kinds, propeller and centrifugal, and, according to the pressure they exert, of low, medium, or high pressure. They are now often driven electrically, in which case there is advantage in coupling them directly with the motor.
Propeller fans have curved screw-shaped blades and are set at right angles in the duct upon the column of air in which they act by suction. The air is moved in the direction of the axis of the fan, and generally it is possible, by reversing the action, to force air in instead of extracting it. The draught produced is a low-pressure one (generally less than 15 mm. of water). The current of air set in motion travels at a relatively slow speed, yet such fans are capable, when suitably proportioned, of moving large volumes of air. Propeller fans are specially suitable for the general ventilation of rooms when the necessary change of air is not being effected by natural means.
Fig. 47.—The Blackman (Belt-driven) Fan.
Centrifugal or high-pressure fans (see figs. [48a] and [48b] ) are always encased in such a way that the exhaust ducts enter on one or both sides of the axis. The air thus drawn in is thrown by the quickly rotating numerous straight blades to the periphery and escapes at the outlet. The centrifugal fan travels at a great speed, and the air current has therefore great velocity and high pressure. When the pressure is less than 120 mm. it is described as a medium, and when greater, a high-pressure fan. For the former a galvanised iron casing suffices; for the latter the casing requires to be of cast iron. Medium pressure centrifugal fans are used to exhaust dust or fumes locally from the point at which they are produced. They play a great part in industrial hygiene.
Fig. 48a.—‘Sirocco’ Centrifugal Fan
Fig. 48b.—Showing exhaust aperture and fan blades
High-pressure fans are used mainly for technical purposes, as, for example, the driving of air or gas at high pressure. Localised ventilation is needed to limit diffusion of dust and fumes, which is attained in a measure also by separation of those workrooms in which persons come into contact with poisonous materials from others. Separation of workrooms, however, is not enough, as it is the individual who manipulates the poison for whom protection is desired. To enclose or hood over a dusty machine or fume-producing apparatus completely, or to close hermetically a whole series of operations by complicated technical arrangements, is only possible when no opening or hand feeding is required. Dangerous substances can only be wholly shut in by substitution of machinery for handwork.
Fig. 49.—Localised Exhaust Ventilation in a Colour Factory (Sturtevant Engineering Co., Ltd.)
| Fig. 50a. | Fig. 50b. |
Ball Mills
Where, however, absolute contact is unavoidable the dust or fume must be carried away at its source. This is done by exhaust ventilation, locally applied, in the following manner: A suitable hood or air guide of metal or wood is arranged over the point where the dust is produced, leaving as small an opening as possible for necessary manipulations. The hood is connected with a duct through which the current of air travels. An exhaust current dependent upon heat will only suffice in the case of slight development of dust or fumes. As a rule exhaust by a fan is necessary. Where exhaust ventilation has to be arranged at several points all these are connected up by branch ducts with the main duct and centrifugal fan. Where the ducts lie near the floor it is advisable to fix adjustable openings in them close to the floor to remove the sweepings.
Fig. 51.—Ventilated Packing Machine (after Albrecht)
A Worm; B Collector; D Fan; E Filter bag; J, F Movable shutters; H Jolting arrangement
It is important for the exhaust system of ventilation to be designed in general so that the dust is drawn away from the face of the worker downwards and backwards. Many horrible arrangements are found in which the dust is first aspirated past the mouth and nose before it is drawn into a hood overhead. The proportions of the branch pipes to the main duct require to be thought out, and friction and resistance to the flow must be reduced as far as possible by avoidance of sharp bends. Branch pipes should enter the main duct at an angle of thirty degrees. A completely satisfactory system requires very special knowledge and often much ingenuity when the apparatus is complicated.
Disintegrators and edge runners can generally be covered in and the cover connected with an exhaust. Ball mills, when possible, are best as the rotating iron cylinder containing the steel balls and the material to be pulverised is hermetically closed.
Powdered material can be carried mechanically from one place to another by worms, screws, endless bands, or be driven in closed pipes by means of compressed air. The inevitable production of dust in packing can be avoided by the use of ventilated packing machines, which are especially necessary in the case of white lead, bichromates, basic slag, &c.
Fig. 52.
The difficulty is great in preventing dust in sieving and mixing, since this is mainly done by hand. Still here, for example, by use of cases with arm-holes and upper glass cover, injury to health can be minimised. Benches with a wire screen and duct through which a downward exhaust passes are useful in sorting operations ([fig. 52]).
[Fig. 53] illustrates a grinding or polishing wheel fitted with localised exhaust.
Fig. 53.—Removing Dust from Bobs and Mops (James Keith & Blackman Co., Ltd. By permission of the Controller of H.M. Stationery Office)
To prevent escape of injurious gases all stills and furnaces must be kept as airtight as possible and preferably under a slight negative pressure. Agitators must be enclosed and should be fitted with arrangements for carrying on the work mechanically or by means of compressed air and, if necessary, exhaust ventilation applied to them. The aim should be to enclose entirely drying and extracting apparatus.
Fig. 54.—‘Cyclone’ Separator (Matthews & Yates, Ltd.)
An important question remains as to what shall be done with the dust and fumes extracted. In many cases they cannot be allowed to escape into the atmosphere outside, and in the interests of economy recovery and utilisation of the waste is the thing to aim at. This vital subject can only receive barest mention here. The dust or fumes extracted require to be subjected to processes of purification with a view to recovery of the often valuable solid or gaseous constituents and destruction of those without value.
Fig. 55a. Fig. 55b.
Dust-filter of Beth-Lübeck (after Albrecht)
Fig. 56.—Dust-filter of Beth-Lübeck—Detail
Collection of dust may take place in settling chambers as in a cyclone separator in which the air to be purified is made to travel round the interior of a cone-shaped metal receptacle, depositing the dust in its passage ([see fig. 54]).
Fig. 57.—Arrangement for Precipitating Dust (after Leymann)
A Entry of dust laden air; B Fan; C Purified air; D Pipe carrying away water and last traces of dust; E Worm carrying away collection of dust.
The most effective method, however, is filtration of the air through bags of canvas or other suitable fabric as in the ‘Beth’ filter (see figs. [55] and [56]). In the ‘Beth’ filter a mechanical knocking apparatus shakes the dust from the bag to the bottom of the casing, where a worm automatically carries it to the collecting receptacle. In the absence of mechanical knocking the filtering material becomes clogged and increases the resistance in the system. Contrivances of the kind unintelligently constructed become a source of danger to the workers. Dust of no value is usually precipitated by being made to pass through a tower down which a fine spray of water falls. If the gases and fumes can be utilised they are either absorbed or condensed—a procedure of the utmost importance for the protection of the workers.
Condensation of the gases into a liquid is effected by cooling and is an essential part of all processes associated with distillation. The necessary cooling is effected either by causing the vapours to circulate through coils of pipes surrounded by cold water or by an increase in the condensing surface (extension of walls, &c.), and artificial cooling of the walls by running water.
Absorption of gases and fumes by fluids (less often by solid substances) is effected by bubbling the gas through vessels filled with the absorbing liquid or conducting it through towers (packed with coke, flints, &c.), or chambers down or through which the absorbent flows. Such absorption towers and chambers are frequently placed in series.
The material thus recovered by condensation and absorption may prove to be a valuable bye-product. Frequently the gases (as in blast furnace gas, coke ovens, &c.) are led away directly for heating boilers, or, as in the spelter manufacture, to make sulphuric acid.
V
PREVENTIVE REGULATIONS FOR CHEMICAL INDUSTRIES
Sulphuric Acid Industry
(See also pp. [4-14] and [171])
Danger arises from escape of acid gases or in entering chambers, towers, containers, &c., for cleaning purposes. The whole chamber system, therefore, requires to be impervious and the sulphur dioxide and nitrous gases utilised to their fullest extent—a procedure that is in harmony with economy in production. The pyrites furnace must be so fired as to prevent escape of fumes, which is best attained by maintenance of a slight negative pressure by means of fans. The cinders raked out of the furnace because of the considerable amount of sulphur dioxide given off from them should be kept in a covered-in place until they have cooled. Any work on the towers and lead chambers, especially cleaning operations, should be carried out under strict regulations. Such special measures for the emptying of Gay-Lussac towers have been drawn up by the Union of Chemical Industry. Before removal of the sediment on the floor they require a thorough drenching with water, to be repeated if gases are present. Perfect working of the Gay-Lussac tower at the end of the series of chambers is essential to prevent escape of acid gases. In a well-regulated sulphuric acid factory the average total acid content of the final gases can be reduced to 0·1 vol. per cent. Under the Alkali Works Regulation Act of 1881 the quantity was limited to 0·26 per cent. of sulphur dioxide—and this should be a maximum limit.
Entering and cleaning out chambers and towers should only be done, if practicable, by workmen equipped with breathing apparatus, and never without special precautionary measures, as several fatalities have occurred at the work. Towers, therefore, are best arranged so as to allow of cleaning from the outside; if gases are noticed smoke helmets should be donned. The same holds good for entering tanks or tank waggons. After several cases of poisoning from this source had occurred in a factory the following official regulations were issued:
The deposit on the floor of waggons or tanks shall be removed either by flushing with water without entering the tank itself, or if the tank be entered the deposit is to be scooped out without addition of water or dilute soda solution.
Flushing out shall only be done after the workmen have got out.
Workmen are to be warned every time cleaning is undertaken that poisonous gases are developed when the deposit on the floor is diluted.
Acid eggs, further, are to be provided with a waste pipe and manhole to enable cleaning to be done from outside.
The poisoning likely to arise is partly due to arsenic impurity (development of arseniuretted hydrogen gas) in the sulphuric acid used. Unfortunately arsenic free acid is very difficult to obtain.
Hydrochloric Acid—Saltcake and Soda Industries
(See also pp. [15-23] and [170])
Preventive measures here depend upon observance of the general principles already discussed.
The saltcake pan and reverberatory furnace require to be accurately and solidly constructed and the process carefully regulated. Regulations indeed were drawn up at an early date in England as to their working to prevent escape of gases when adding the acid, raking over in the reverberatory furnace, and withdrawal of the still fuming saltcake.
The following are the most important of these recommendations:
The saltcake pan must not be charged when overheated.
Sulphuric acid shall be added only after all the salt has been charged and the door shut.
If hydrochloric acid fumes escape at the door when the Glover acid flows in the flow must be interrupted.
All doors must be closed while work is in progress.
Definite times shall be fixed for withdrawal of the saltcake in order to try and ensure that it be not still fuming, but should this be the case cold sulphate of soda shall be sprinkled over it.
The general principle should be observed of maintaining a slight negative pressure in the furnace by insertion of a fan in the gas conduit so as to avoid possible escape of gas. The fuming saltcake is best dealt with by depositing it at once to cool in ventilated receptacles or chambers.
On grounds of economy and hygiene as complete an absorption as possible of the hydrochloric acid gas developed in the saltcake and soda ash process is to be aimed at, by conveying it through impervious conduits to the bombonnes and lofty absorption tower filled with coke or flints down which water trickles. The entire loss of hydrochloric acid should not amount to more than 1·5 per cent. of the whole. Under the Alkali Act at first 5 per cent. was allowed, but this is excessive now in view of improved methods of condensation.
In the Leblanc process the revolving furnace is on health grounds to be preferred to the hand furnace. Such a furnace occupies the space of but three hand furnaces and can replace eighteen of them. The vast accumulation of waste, consisting mainly of calcium sulphide, and generating sulphuretted hydrogen gas in such amount as to constitute a nuisance, is only partially prevented by the Chance-Claus and other methods of recovery, and makes it most desirable to adopt the Solvay ammonia process.
Note.—Sulphonal, Oxalic acid, Ultramarine, Alum.—The production of sulphonal is intensely unpleasant owing to the disagreeable smell (like cats’ excrement) of the mercaptan developed. All work therefore must be carried on in air-tight apparatus under negative pressure and careful cooling. Any escaping fumes must be absorbed in solution of acetone and fine water spray.
Preparation of oxalic acid unless carried on in closed-in vessels gives rise to injurious and troublesome fumes. If open pans are used, hoods and ducts in connection with a fan should be placed over them.
Grinding of ultramarine and alum requires to be done in closed-in mills, and any dust drawn away by locally applied ventilation and filtered. The gases given off in the burning process contain 3 per cent. of sulphur dioxide, which requires to be absorbed—a procedure most easily effected in towers where the upstreaming gas comes into contact with a dilute solution of lime or soda.
Chlorine, Bleaching Powder, Chlorine Compounds
(See also pp. [23-9] and [173])
What has been said as to imperviousness of apparatus, negative pressure maintained by the tall chimney stack or earthenware or fireclay fan, &c., applies equally here. The exhaust ventilation is also required to aspirate the gas into the bleaching chambers.
At the end of the system there must be either a tower packed with quicklime to absorb the last traces of chlorine or such a number of bleach chambers into which the gas can be led that no chlorine escapes. Production of chlorine gas electrolytically is to be preferred to other processes on hygienic grounds.
Careful cleanliness is the best prophylactic against occurrence of chlorine rash among persons employed in the electrolytic production of chlorine. In some factories attempt has been made to use other substances (magnetite) instead of carbon for the anode, and the success attending their adoption is further proof that the tar cement at the anode helped to cause the acne.
In the Weldon process care must be taken that the water lutes are intact, and the stills must not be opened before the chlorine has been drawn off. All processes in which manganese dust can arise (grinding of manganese dioxide and drying of Weldon deposit) should be done under locally applied exhaust. The bleaching powder chambers must be impervious and care taken that they are not entered before the chlorine has been absorbed. Usually the number of lime chambers connected up with each other is such that no chlorine escapes free into the air. Emptying of the finished product should not be done by hand, as considerable quantities of chlorine escape and make the work extremely irksome. Mechanical methods of emptying should be adopted in substitution for hand labour, and of these the Hasenclever closed-in apparatus is the best.
Nitric Acid and Explosives
(See also pp. [39-49] and [172])
In the production of nitric acid complete imperviousness of the system and as complete condensation of the gases as possible by means of tourilles, cooling condensers, and the requisite number of towers are necessary. The method suggested by Valentine of manufacture of nitric acid in apparatus under a partial vacuum has advantages from a hygienic standpoint. Earthenware fans are used to force the nitric acid gases onwards and have the advantage of creating a negative pressure. Great care is needed in handling, emptying, packing, conveying, and storing the acid in consequence of the danger from breaking or spilling. The bottles used must be in perfect condition and must be well packed. No greater stock of nitric acid should be allowed in a room than is absolutely necessary, and care must be exercised in the event of a carboy breaking that the spilt acid does not come into contact with organic substances, as that would increase development of nitrous fumes.
Workers must be warned not to remain in rooms in which acid has been spilt. They are only to be entered by workers equipped with breathing apparatus (smoke helmets).
Among the special regulations on the subject may be mentioned those of the Prussian Ministerial Decree, dated January 8, 1900, concerning nitrous fumes and means of protection for workers employed with the acid. What has been said on p. [257] in regard to the transport of sulphuric acid applies equally to nitric acid.
In the nitrating process in the manufacture of explosives (see p. [47]) it is essential that the apparatus is hermetically closed, that agitation is done mechanically, or better still by means of compressed air, and that any fumes developed are exhausted and condensed. In the preparation of nitro-glycerin (see p. [46]) the gases developed in the nitration of the waste acid require to be carefully condensed. Contact of nitro-glycerin with the skin has to be avoided and the attention of the workers drawn to the danger. Preparation of gun cotton (see p. [48]) takes place in machines which are at the same time nitrating and centrifugalising machines. The apparatus is first filled with the nitrating acid and the cotton added; the fumes are drawn off by earthenware ducts and fans, and lastly the bulk of the acid is removed by centrifugal action. Such machines carry out effectually the principles of industrial hygiene.
In the preparation of fulminate of mercury nitrous fumes, cyanogen compounds, and acetic acid compounds are developed by the action of the nitric acid on mercury, and require to be dealt with by exhaust ventilation.[G]
Artificial Manures, Fertilizers
In grinding phosphorite and superphosphates, corrosive dust is produced. All grinding operations must, therefore, be carried out automatically in closed apparatus (ball mills, disintegrators, &c.). In making the phosphorite soluble by treatment with sulphuric acid, and subsequent drying of the product, corrosive hydrofluoric acid gas is developed, which requires to be carried away by an acid proof exhaust fan, and condensed in a tower by water ([see fig. 58]). The modern revolving drying machines are especially serviceable.
Fig. 58.—Washing tower for hydrofluoric acid (after Leymann.)
In the production of basic slag corrosive dust is given off, causing ulceration of the mucous membrane. Grinding and other manipulations creating dust must be carried on in apparatus under local exhaust ventilation. The following—somewhat shortened—are the German Imperial Regulations, dated July 3, 1909, for basic slag factories.
Basic Slag Regulations
1. Workrooms in which basic slag is crushed, ground, or stored (if not in closed sacks) shall be roomy and so arranged as to ensure adequate change of air. Floors shall be of impervious material allowing of easy removal of dust.
2. Preliminary breaking of the slag by hand shall not be done in the grinding rooms, but either in the open air or in open sheds.
3. Slag crushers, grinding mills, and other apparatus shall be so arranged as to prevent escape of dust as far as possible into the workrooms. They shall be provided with exhaust ventilation and means for collecting the dust if this cannot be done in the absence of dust.
4. Arrangements shall be made whereby barrows conveying material to the grinding mills shall be emptied directly into partially hooded hoppers provided with exhaust ventilation so as to prevent escape of dust into the workrooms.
5. The casing and joints of the grinding mills, ducts, dust collectors and sieves shall be airtight; if leaks are noticed they must be repaired forthwith.
6. Ducts, dust collectors and sieves shall be so arranged as to enable periodical cleansing to be undertaken from the outside.
7. Repairs of the plant mentioned in Para. 5 in which workers are exposed to inhalation of slag dust shall be entrusted by the occupier only to such workers as wear respirators supplied for the purpose or other means of protecting mouth and nostrils such as wet sponges, handkerchiefs, &c.
8. Emptying of slag powder from the grinding mills and dust collectors and transference to the store rooms shall only be done in accordance with special regulations designed to minimise dust.
9. Filling slag powder into sacks from the outlets of the mills, elevating and discharging it into receptacles shall only be done under efficient exhaust ventilation.
10. Sacks in which the powder is transported and piled in heaps shall be of a certain defined strength to be increased in the case of sacks to be piled in heaps more than 3½ metres in height. Special rooms separated from other workrooms shall be provided for storage of slag powder in sacks. Only the sacks representing the previous day’s production may be stored in the grinding rooms.
Basic slag in powder and not in sacks shall be kept in special storage rooms shut off entirely from other workrooms. No person shall enter such storage rooms when they are being filled or emptied. Discharging the contents of the sacks into them shall be done under exhaust ventilation.
11. The floors of the workrooms described in Para. 1 shall be cleaned before the commencement of each shift or in an interval during each shift. No person except those engaged in cleaning shall be present during the operation. If cleaning is effected by sweeping, the occupier shall require the persons doing it to wear the respirators provided or other protection for the mouth and nose.
12. The occupier shall not permit the workers to bring spirits into the factory.
13. A lavatory and cloakroom and, separated from them and in a part of the building free from dust, a meal room shall be provided. These rooms shall be kept clean, free from dust, and be heated during the winter.
In the lavatory and cloakroom water, soap, and towels shall be provided and adequate arrangements shall be made for keeping the clothing taken off before commencing work.
The occupier shall give the persons employed opportunity to take a warm bath daily before leaving work in a bathroom erected inside the factory and heated during the winter.
14. No woman or male young person under eighteen years of age shall work or remain in a room into which basic slag is brought.
Persons under eighteen years of age shall not be employed in beating sacks which have contained basic slag.
15. No person employed in breaking or grinding, emptying, packing, or storing basic slag, shall work more than ten hours daily.
There shall be intervals during working hours amounting in the aggregate to two hours, one of them lasting at least an hour. If duration of employment daily is limited to seven hours with never longer than four hours’ work without an interval, only one interval of at least one hour is required.
16. For work mentioned in Para. 15 no person shall be employed without a certificate from an approved surgeon stating that he is free of disease of the lungs and not alcoholic. The occupier shall place the supervision of the health of the workers under a surgeon who shall examine them at least once a month for signs of disease of the respiratory organs and alcoholism. Workers engaged in the operations mentioned in Para. 15 shall be suspended from employment when the surgeon suspects such illness or alcoholism. Those showing marked susceptibility to the effect of basic slag dust shall be permanently suspended.
17. A health Register shall be kept in which shall be entered the precise employment, duration of work, and state of health of the persons employed.
18. The occupier shall obtain a guarantee from the workers that no alcohol or food shall be taken into the workrooms.
Preparation of Hydrofluoric Acid
The fumes given off in the preparation of hydrofluoric acid require to be collected in leaden coolers and vessels; that which escapes requires to be absorbed by a water spray in towers. The apparatus must be impervious and kept under a slight negative pressure.
Chromium Compounds
(See also pp. [55-8] and [185])
The German Imperial Decree, dated May 16, 1907, contains the preventive measures necessary in bichromate factories. According to this, workers suffering from ulceration of the skin (chrome holes, eczema) are not to be employed except on a medical certificate that they are free from such affections, and daily examination for signs of ulceration is enjoined, so that those affected may receive prompt treatment. Further, periodical medical examination of the workers is required at monthly intervals. Respirators (for work in which dust cannot be avoided), with lavatory, cloakroom, and meal room accommodation, are to be provided, and also baths. In handling bichromates wearing of impervious gloves may be necessary, and smearing the hands and face with vaseline is recommended. In addition diffusion of dust and fumes must be minimised; machines in which mixing, crushing, and grinding are done must be impervious, and provided with exhaust ventilation. Charging of the furnaces, where possible, should be effected mechanically and the fumes developed both in manipulation of the furnaces and from hot bichromate liquor removed by an exhaust.
A leaflet containing directions for workers coming into contact with chromium compounds in chemical factories, dyeing, tanning, wood staining, calico printing, wall paper printing, painting, &c., has been drawn up by Lewin. It contains a list of the poisonous chrome compounds and of the industries in which chrome poisoning occurs, information as to the action of chrome upon the skin and mucous membrane, and the preventive measures necessary. Among the last named are: smearing the skin with oil, use of impervious gloves, respirators in work where dust arises, necessity of cleanliness, and periodical medical examination.
For the chrome tanning industry the following leaflet was drawn up by the Imperial Health Office in Berlin, which succinctly states the measures against chrome poisoning in these industries and contains much practical information for the workers:
In chrome tanning by the two bath process, the first bath containing potassium bichromate and hydrochloric acid has a corroding effect upon broken surfaces of the skin (scratches, chapped hands, eruptions, &c.). In consequence, they develop into round ulcers (chrome holes) with hard raised edges which are difficult to heal and go on increasing in size unless work at the process is temporarily given up. In persons with very sensitive skin, even though the surface may be intact, handling the liquor brings on sometimes an obstinate rash (eczema) on the hands and forearms.
The solution used in the one bath process has no corrosive action, but it is a strong poison, just as is the solution of potassium bichromate of the two bath process. If swallowed, the solutions cause vomiting, diarrhœa, kidney trouble, and even death. Chromium compounds can also enter the body through skin wounds and cause illness.
Prevention.—In order to prevent the occurrence of chrome ulceration, workers employed with chrome or chrome solutions must be especially careful in avoiding injury to the skin of the hands or forearms. This applies especially to workers who carry the vessels containing bichromate, who weigh and dissolve the potassium bichromate, or who come into contact with the tanning liquor or with undressed skins and hides which have lain in the liquor.
If, in spite of precautions, eruptions, rashes, or ulceration occur, all work necessitating contact with corrosive tanning liquors should be suspended until they are healed.
In order to reduce risk of action of the liquor on the skin, workers employed in the process described would do well if, before commencing work, they carefully smeared hands and forearms with unsalted lard, vaseline, or the like, and during work avoided, as much as possible, soiling the bare hands and arms with the liquor.
If, nevertheless, a worker has contracted a chrome hole, or eruption, he should consult a medical man, informing him at the same time of the nature of his work.
To avoid internal absorption of chrome, workers preparing the baths must carefully avoid inhaling the dust of chromium salts. These and all other workers engaged with the liquors containing chromium must not take food and drink while at work. Working suits should be taken off and face and hands washed with soap before eating or drinking, and before leaving the factory.
Petroleum, Benzine
(See also pp. [59-64] and [222-4])
As crude petroleum and the higher fractions first distilled from it affect the skin injuriously, wetting the skin should be avoided, and careful cleanliness on the part of the workers enjoined. Workers exposed to the influence of gases escaping from naphtha springs and wells should be equipped with breathing apparatus (smoke helmets); this applies to those who have to enter stills and other apparatus connected with the distillation of petroleum.
In the preparation of petroleum by sulphuric acid sulphur dioxide in great quantity is developed, constituting a distinct danger to the workers. This process, therefore, should be carried on in closed vessels furnished with mechanical stirrers or compressed air agitators. The most suitable apparatus is that illustrated in [fig. 13].
Petroleum tanks must be thoroughly aired before they are cleaned and should be entered only by workers equipped with breathing apparatus. Apparatus containing petroleum and benzine requires, as far as possible, to be closed in and air tight (as, for example, in the extraction of fat from bones and oil seed, in the rubber industry, and in chemical cleaning establishments); where benzine fumes develop they should be immediately drawn away by suitably applied exhaust ventilation. This is necessary, on account of the danger of fire, in chemical cleaning establishments where purification is effected by means of benzine in closed drums.
Regulations for benzine extraction plants are contained in the Prussian Ministerial Decree, dated January 5, 1909, for benzine extraction works, and also in that of August 3, 1903, for dry-cleaning premises, to which last were added ‘Directions for safety,’ containing important regulations as to risk from fire. From our standpoint the following points are of interest: care is to be taken to provide and maintain exhaust ventilation directly across the floor. The air, however, must not be allowed to pass near any fire. Drying rooms especially are to be lofty and airy, and separated from other workrooms. In factories with mechanical power the authorities may require provision of artificial ventilation for the drying rooms. Washing machines, centrifugalising machines, and benzine rinsing vessels should be furnished with well-fitting covers to be removed only for such time as is absolutely necessary for putting in and taking out the articles to be cleaned, shaken, or rinsed. The vessels named are to be examined as to their imperviousness at least once every quarter by a properly qualified person. The condition in which they are found is to be noted in a book to be shown to the Factory Inspector and police authorities on demand.
Lastly, substitution for benzine of other less poisonous substances such as carbon tetrachloride has been urged.
Phosphorus, Lucifer Matches
(See also pp. [49-53] and [190])
In view of the danger of the lucifer match industry, measures were taken at an early date in almost all civilised states to guard against phosphorus poisoning, and in many countries have led to the prohibition of the use of white phosphorus. Complete prohibition of its manufacture and use was first enacted in Finland (1872) and in Denmark (1874). Prohibition was decreed in Switzerland in 1879 (in January 1882 this was revoked, but again enacted in 1893), and in the Netherlands in 1901. In Germany the law prohibiting the use of white phosphorus came into force in January 1908, and runs as follows:
1. White or yellow phosphorus shall not be employed in the production of matches and other lighting substances. Lighting substances made with white phosphorus shall not be kept for sale, or sold, or otherwise brought on the market. Provided that this shall not apply to ignition strips which serve for the lighting of safety lamps.
2. Persons wilfully infringing this law shall be punished by a fine of 2000 marks. If the infringement occurs through ignorance the fine shall consist of 150 marks.
In addition to the fine, all prohibited articles produced, imported, or brought into the trade shall be confiscated, as well as the implements used in their production, without reference to whether they belong to the person convicted or not. If prosecution or conviction of the guilty party cannot be brought home, confiscation nevertheless is to be carried out independently.
Roumania and France have a state monopoly of matches; in these states no white phosphorus matches have been produced since 1900 and 1898 respectively. France, by the Law of December 17, 1908, signified concurrence with the International Convention in regard to the prohibition of the use of white phosphorus.
In Sweden and Norway the prohibition of white phosphorus is in force only for the home trade. A Swedish Decree, dated December 9, 1896, permitted factories carrying on the manufacture for export to use white phosphorus, and almost precisely similar provisions are contained in the Norwegian Decree. The Swedish Decree, dated March 30, 1900, permits white phosphorus matches to be exported, but not to be sold in the country. In Austria difficulties in regard to prohibition of white phosphorus arose owing to trade conditions (especially in the East), and the attitude of the states competing in the lucifer match trade, particularly Italy and Japan. Austria, therefore, made agreement with international prohibition of white phosphorus, dependent on the attitude of Japan; since Japan did not concur, the decision of Austria fell through. When, however, Italy in the year 1906 joined the Convention, the difficulties were also overcome in Austria, and by a law similar to that of Germany, dated July 13, 1909, prohibition of the manufacture and sale of white phosphorus matches dates from the year 1912.[H]
Belgium has refrained from prohibition of white phosphorus, but on the other hand has passed a series of enactments relating to the match manufacture, of which the most essential are here cited, since they characterise the measures which come into consideration for factories in which white phosphorus is still employed.
Royal Decree, dated March 25, 1890, modified by the Royal Decree, dated February 12, 1895, and November 17, 1902, concerning employment in lucifer match factories.
1. In match factories where white phosphorus is used, mixing the paste and drying the dipped matches shall be carried on in a place specially set apart for the purpose.
2. Mixing the paste shall be carried on in an entirely closed vessel or in one connected with an efficient exhaust draught locally applied.
The proportion of white phosphorus in the paste shall not exceed in weight 8 per cent. of the total material, not including water.
3. Hoods and ducts communicating with an exhaust draught shall be installed at the level of the plates for dipping white phosphorus matches, and over the vessels containing the paste.
4. Drying rooms for white phosphorus matches, if entered by the workers, shall be mechanically ventilated.
5. Rooms in which phosphorus fumes can arise shall be lofty and well ventilated, preferably by an exhaust at the level of the work benches, communicating with the main chimney stack.
The workrooms shall be kept clean. No food or drink shall be taken in them.
6. In every match factory the workers shall have at their disposal a special cloak room and suitable and sufficient washing accommodation, so as to be able to change clothes before commencing, and at the end of, work, and to wash the hands and face on leaving.
Cleanliness will be obligatory upon the workers manipulating phosphorus paste or matches.
7. Workers coming into contact with phosphorus paste or matches shall be examined monthly by a surgeon appointed by the Minister of Industry, who shall be paid by the occupier.
Workers having decayed, unstopped teeth, or exhibiting symptoms of gingivitis or stomatitis, or in poor health at the time of examination, shall be temporarily suspended from work.
The surgeon shall enter the results of his monthly examinations in a prescribed register.
This register shall be shown to the Factory Inspector on demand.
These decrees are supplemented by further orders regarding the taking of samples of paste in match factories and store houses (Royal Orders of March 25, 1890; February 12, 1895; April 18, 1898; November 17, 1902).
As is evident from the Belgian enactment, in states where prohibition of white phosphorus is not in force, palliative measures only are possible and even then they can only be enforced in large factories when automatic machinery is used to eliminate hand labour in dangerous operations. In this respect the introduction of closed, ventilated, mechanical mixing apparatus provided with mechanical stirrers, closed and ventilated mechanical dipping and drying apparatus, are especially important. Certain modern American machines carry through the whole complicated process of the phosphorous match industry automatically. Seeing that prohibition of white phosphorus is an accomplished fact and that matches free from risk in their manufacture answer every purpose, the universal enforcement of the prohibition of white phosphorus should be striven for in civilised states.
Carbon bisulphide
(See also pp. [68-71] and [193-5])
Use of carbon bisulphide in the vulcanising of indiarubber goods by dipping them into the liquid and subsequently drying them (usually in a current of hot air) causes development of carbon bisulphide fumes in considerable quantity, especially if the articles to be dried are laid on shelves or hung up in the workroom, a procedure which should never be permitted. Drying must be carried out under local exhaust ventilation.
All vessels holding carbon bisulphide used for dipping can be placed in a wooden channel above the dipping vessels, provided with openings for manipulation, and connected with an exhaust system.
The following are the German Imperial Regulations, dated March 1, 1902, for vulcanising of indiarubber by means of carbon bisulphide:
Vulcanising by Means of Carbon Bisulphide
(Notice concerning the erection and management of industrial premises in which indiarubber goods are vulcanised by means of carbon bisulphide or chloride of sulphur.)
The following regulations shall apply in accordance with paragraph 120 (e) of the Industrial Code:
1. The floor of such rooms as are used for the vulcanising of indiarubber goods by means of carbon bisulphide shall not be lower than the surrounding ground. The rooms shall have windows opening into the outer air, and the lower halves shall be capable of being opened so as to render possible sufficient renewal of air.
The rooms shall be ventilated by fans mechanically driven. With the approval of the higher authorities permission to dispense with mechanical draught may be allowed, provided that in other ways powerful change of air is secured. With the approval of the higher authorities special ventilating arrangements can be dispensed with if the fumes of carbon bisulphide are removed immediately, at the point where they are produced, by means of a powerful draught, and in this way purity of the air be secured.
2. The vulcanising rooms shall not be used as a dwelling, or for sleeping in, or for preparing food in, or as a store, or drying room, nor shall other processes than those of vulcanising be carried on in them. No persons, except those engaged in vulcanising processes, shall be allowed in the rooms.
There shall be at least 20 cubic meters (700 cubic feet) of air space allowed for each person employed therein.
3. Only such quantities of carbon bisulphide shall be brought into the vulcanising rooms as shall serve for the day’s supply. Further storage shall be made in a special place separate from the workrooms. Vessels to hold the vulcanising liquid shall be strongly made, and when filled and not in use shall be well covered.
4. Vulcanising and drying rooms shall be warmed only by steam or hot-water pipes.
These rooms shall be lighted only by means of strong incandescent electric lamps.
Exceptions from paragraphs 1 and 2 may be allowed by the higher authorities.
5. Machines intended for vulcanising long sheets of cloth shall be covered over (e.g., with a glass casing) so as to prevent as far as possible the entrance of carbon bisulphide fumes into the workrooms, and from the casing the air shall be drawn away effectually by means of a fan mechanically driven. Entrance to the space which is enclosed shall only be allowed in case of defects in the working.
In cases where a covering of the machine is not practicable for technical reasons the higher authorities can, if suitable means of protection are used (especially when the machine is placed in an open hall, and provided that no person works at the machine for more than two days a week), allow of exception to the above arrangement.
6. Vulcanising of other articles (not mentioned in par. 5), unless carried out in the open air, shall be done in covered-in boxes into which the worker need only introduce his hands, and so arranged as to keep the fumes away from the face of the worker.
The air must be drawn away from the box by means of a powerful draught.
7. Rule 6 shall apply in vulcanising both the outside and inside of indiarubber goods. In vulcanising the inside no worker shall be allowed to suck the fluid through with the mouth.
8. The goods after their immersion in the vulcanising fluid shall not lie open in the room, but shall either be placed under a ventilated cover or at once be carried into the drying chamber.
The drying chamber or drying rooms in which the wares are exposed to artificial heat immediately after vulcanising shall be so arranged that actual entrance into them for the putting in or taking out of the vulcanised goods shall not be necessary. No person shall be allowed to enter the drying chamber while work is going on. The higher authorities can permit of exceptions to this rule in the case of the drying of long rolls if sufficient protecting arrangements are made.
9. When vulcanisation is effected by means of chloride of sulphur the vessels or chambers used for holding it shall be so arranged that escape of the fumes is prevented.
No person shall enter the vulcanising chamber until the air in the chamber has been completely changed; it shall not be used for purposes other than vulcanising.
10. Employment in vulcanising with carbon bisulphide or in other work exposing the workers to carbon bisulphide vapour shall not be allowed without a break for more than two hours and in no case for more than four hours in one day; after two hours a pause of at least one hour must be allowed before resumption.
No person under 18 years of age shall be employed.
11. The occupier shall provide all workers employed in work mentioned in paragraph 10 with proper and sufficient overalls. By suitable notices and supervision he shall see that when not in use they are kept in their proper place.
12. Separate washing accommodation and dressing-rooms for each sex shall be provided, distinct from the workrooms, for all persons employed as stated in paragraph 11.
Water, soap, and towels and arrangements for keeping the clothes put off before the commencement of work shall be provided in sufficient amount.
13. The occupier shall appoint a duly qualified medical practitioner (whose name shall be sent to the Inspector of Factories) to supervise the health of those exposed to the effects of carbon bisulphide. He shall examine the workers once every month with a view to the detection of poisoning by carbon bisulphide.
By direction of the medical practitioner workers showing signs of carbon bisulphide poisoning shall be suspended from work and those who appear peculiarly susceptible shall be suspended permanently from work in processes mentioned in paragraph 10.
14. The occupier shall keep a book, or make some official responsible for its keeping, of the changes in the personnel in the processes mentioned in paragraph 10 and as to their state of health. The book shall contain—
(1) The name of the person keeping the book;
(2) The name of the appointed surgeon;
(3) Surname, Christian name, age, residence, date of first employment, and date of leaving of every worker mentioned in paragraph 10, and the nature of the employment;
(4) The date of any illness and its nature;
(5) Date of recovery;
(6) The dates and results of the prescribed medical examination.
15. The occupier shall require the workers to subscribe to the following conditions:—
No worker shall take food into the vulcanising rooms;
The workers shall use the protection afforded in paragraphs 5-7 and use the overalls in the work named;
The workers shall obey the directions of the occupier given in accordance with Rule 5, paragraphs 1 and 2, Rule 8, paragraphs 1 and 2, and Rule 9, paragraph 2. Workers contravening these orders shall be liable to dismissal without further notice.
If in a factory regulations already exist (paragraph 134(a) of the Industrial Code) the above shall be included.
16. In the vulcanising rooms mentioned in Rule 1 there shall be posted up a notice by the police stating—
(a) The cubic capacity of the rooms;
(b) The number of workers who may be employed.
Further, in every vulcanising room there shall be posted up in a conspicuous place and in clear characters Rules 1-15 and the conditions in paragraph 15.
Reference should be made also to the Prussian Ministerial Decree, dated February 23, 1910, on the preparation, storing, and manufacture of carbon bisulphide, and to the French Ministerial Circular, dated January 20, 1909 (Manufacture of Indiarubber).
Employment of benzine and chloride of sulphur for vulcanising is, from a hygienic standpoint, to be preferred to that of the much more dangerous carbon bisulphide. The same applies also to the process of the extraction of fat.
In the references made to general arrangements for the protection of workers dealing with poisons, stress was laid on the complete enclosing of extraction apparatus. This applies, of course, to extraction by means of carbon bisulphide, both on grounds of economy, health, and risk from fire.
On account of the risk to health, efforts have been made to substitute other means of equal efficiency, free from danger. Such a substitute may be found in carbon tetrachloride. This extracts well, and dissolves grease spots (like benzine), is not explosive, is scarcely inflammable, and is less poisonous than the substances commonly used for extraction. Its employment is to be recommended on hygienic grounds, but the relatively high price may stand in the way of its use.
Illuminating Gas Industry. Production of Tar and Coke
(See also pp. [71-90] and [199])
In illuminating gas factories imperviousness of the whole working system is especially important from an economical and hygienic standpoint, since only in this way can danger to the working staff be avoided. This applies especially to the retorts, from which no gas should be allowed to escape. If the exhaust is working satisfactorily this should not be possible, as the pressure of the gas in the retorts during distillation will be a negative one. Correct regulation of pressure is thus of the greatest importance in the prevention of poisoning in gas works.
Further, special precaution is necessary in operations with gas purifying material containing cyanogen, since otherwise the workers suffer from the gases developed from the gas lime.
Work with gas purifying material should be so arranged that injurious gases are carried away by suitable ventilating arrangements. Consideration for the neighbourhood forbids their discharge into the open air, and forbids also operations with the gas purifying material in the open air; therefore non-injurious removal of these gases is necessary.
Quenching of the coke also should, on account of the annoyance to the working staff and to lessen nuisance to the neighbourhood, be carried out so that the fumes are drawn into the main chimney stack.
In coke ovens escape of tarry constituents and of poisonous emanations are prevented by imperviousness of the apparatus, by sufficiency of the exhaust draught, and especially by passing the products of distillation, which cannot be condensed, under a fire, or by absorbing them either with water or oil.
Special precautionary measures are needed further in the distillation of the washing oil, and generally escape of poisonous emanations must be prevented by the greatest possible imperviousness of the distillation system and corresponding regulation of pressure.
Gas Motors (Power Gas Stations)
(See also pp. [80-5])
The following points, taken from an Austrian Ministerial Decree (dated December 2, 1903), for the prevention of poisoning in power gas works, may be useful:
Power Gas Installations
In mixed gas installations (Dowson, water gas) of the older system, the way in which the gas is produced causes the whole apparatus and pipes to be under slight negative pressure, because the steam required for the process must be blown into the generator. In these works, therefore, a small special steam boiler is required and a gas receiver to store the gas.
In more modern suction generator gas installations the piston is used to suck in steam and air as well as the gases arising in the generator and to draw them into the motor cylinder. Thus the whole system is kept in a condition of slight negative pressure during the process. While the suction generator gas system is working, only so much gas is produced as the motor uses for the time being, so that with this system there is no greater store of gas than is requisite.
In such an installation the following rules should be borne in mind:
1. All the apparatus (gas pipes, valves, &c.) must be constructed and maintained in a completely impervious condition. Any water seals especially which may be in use must receive attention.
2. Precautions must be taken to prevent the gases from the generator passing into the coolers and purifiers when the engine is at rest.
3. Care is to be taken when the apparatus is at rest to prevent any possible subsequent escape of gas into the room where the apparatus is installed.
4. The return of explosive gas out of the gas engine into the gas pipe by failure to ignite or other accident, must be made impossible.
5. The apparatus through which the generator is charged must possess a tightly fitting double valve to prevent escape of gas into the room during charging.
6. The pipes for conducting away the unpleasantly smelling bituminous constituents in the water mixed with sulphuretted hydrogen from the scrubbers must not communicate with the workroom.
7. Precautions must be taken to minimise the danger during the cleaning of the generator (removal of ashes and slag).
8. All stop-cocks and valves are to be so arranged that their position at any time (open or shut) is clearly visible from outside.
9. Purifiers with a capacity greater than two cubic meters must be provided with appliances which make possible thorough removal of the gas before they are opened.
10. The gas washing and cleaning apparatus and pipes are to be fitted with gauges indicating the pressure existing in them at any moment.
11. When a suction gas plant is first installed and also at times when there is no gas in the pipes and plant between the generator and the engine, gas must be blown in until all air is expelled before the engine is set going.
12. During the cleaning of apparatus and pipes which, when in action, contain gas, the rooms must be thoroughly ventilated.
13. Rooms in which suction gas plant is installed must be of such a height that all the plant and its connections can be easily reached for cleaning, &c., and be capable of such free ventilation as to render impossible an accumulation of gas.
14. These rooms must be separated from living rooms by a wall without any openings in it. Emanations also must be prevented as far as possible from entering into living or working rooms situated over the gas engine.
15. Erection of apparatus for generating and purifying suction gas in cellars shall only be allowed if specially effective ventilation is provided by natural or mechanical means.
Other Regulations are those of the Prussian Ministerial Decree, dated June 20, 1904, as to the arrangement and management of suction gas premises.
Acetylene Gas Installations
(See also pp. [85-7])
The following regulations for the protection of workers in acetylene gas installations are taken from the Prussian Ministerial Decree, dated 2 November, 1897:
1. Preparation and condensation of acetylene on the one hand, and liquefaction on the other, must be carried on in separate buildings.
2. If the pressure employed for condensation of the gas exceeds eight atmospheres, this work must take place in a room set apart for the purpose.
3. Rooms in which acetylene is prepared, condensed, or liquefied shall not be used as, nor be in direct connection with, living rooms. They must be well lighted and ventilated.
4. The carbide must be kept in closed watertight vessels, so as to ensure perfect dryness and only such quantities shall be taken out as are needed. The vessels must be kept in dry, light, well-ventilated rooms; cellar rooms may not be used for storage purposes.
5. Crushing of carbide must be done with the greatest possible avoidance of dust. Workers are to be provided with respirators and goggles.
6. Acetylene gasometers must be fitted up in the open air or in a well-ventilated room, separated from the gas generator. Every gas receiver must have a water gauge showing the pressure in the receiver.
7. Between the gasometer and receiver a gas purifier must be provided so as to remove impurities (phosphoretted hydrogen, arseniuretted hydrogen, carbon bisulphide, ammonia, &c.).
8. Condensation of acetylene gas at a pressure exceeding ten atmospheres shall only be done in combination with cooling.
Distribution and Use of Power and Illuminating Gas
The Austrian Gas Regulations (of July 18, 1906) contain general provisions as to impermeability and security of the gas pipes and the precautions to be observed in their installation. Special directions follow as to main flues, material, dimensions, branches, and connections, valve arrangements, testing of the pipes against leakage, directions for discovering leaks, and other defects; also the nature of the branch pipes (dimensions and material), valves, cocks, syphons, water seals, and pressure gauges. In addition there are directions as to testing pipes and how to deal with escape of gas, freezing of pipes, and other mishaps.
Ammonia
(See also pp. [90-3] and [175])
In the production of ammonia and ammonium salts (ammonium sulphate) combination of the ammoniacal vapour with the sulphuric acid is accompanied with the formation of volatile dangerous gases containing sulphuretted hydrogen and cyanogen compounds, which produce marked oppression and sometimes endanger the health of the workers. Drawing-off these fumes into the furnace (practised sometimes in small industries) is not advisable, as the sulphuretted hydrogen is burnt to sulphur dioxide; if it is burnt absorption of the sulphur dioxide should follow, or working it up into sulphuric acid (Leymann). Often these gases are freed from cyanogen compounds and sulphuretted hydrogen by means of gas purifying materials, such as are used in gas works. The whole apparatus must be impervious. Where liquids containing ammonia are used exhaust ventilation is necessary.
Cyanogen, Cyanogen Compounds
(See also pp. [93-5] and [195-7])
Processes in which cyanogen gas can develop, require to be done under a powerful exhaust draught.
In the production of cyanogen compounds possibility of the escape of hydrocyanic acid (prussic acid) has to be borne in mind. Such escape is possible in its production from raw animal products.
The most careful cleanliness and observance of general measures for personal hygiene are necessary in factories in which cyanogen compounds are manufactured or handled. In crushing cyanide of potassium the workers should wear indiarubber gloves and respirators. The products should be stored in closed vessels in dry store rooms set apart for the purpose.
Modern cyanide of potassium factories which work up molasses, from which the sugar has been removed, and also residuary distillery liquors, so far conform with hygienic requirements that all the apparatus is under negative pressure, so that poisonous gases cannot escape into the workrooms.
Coal Tar, Tar Products
(See also pp. [96-119])
Care must be taken for the removal of injurious gases developed in the manipulation and use of tar (tar distillation) and in the processes of cleaning connected therewith. This can be most effectively done by carrying on the processes in closed apparatus. Hofmann describes such a factory where all mixing vessels in which the distillation products are further treated are completely closed in, so that even in mixing and running off, no contact is possible with the material.
The vessels for holding tar, tar-water, &c., must be impervious and kept covered. Only the cold pitch and asphalt should be stored in open pits. The cooling of the distillation products and residues, so long as they give off poisonous and strongly-smelling fumes, should be carried out in metal or bricked receivers. Such directions find a place in the ‘Technical Instructions’ appended to the German Factory Code. Without doubt, tar is, because of its smell and for other reasons, unpleasant to handle, and the danger to health from contact with it is not a matter of indifference. Spilling of small quantities of tar during transport and other manipulations can hardly be avoided. Careful cleanliness, therefore, on the part of workers is strongly urged. It may be mentioned that if tar is covered with a layer of tar-water, treatment with acid fluids develops sulphur and cyanogen compounds, which may affect the workers. Tar water should, therefore, be separated carefully from the tar and used for the preparation of ammonia.
The same remarks as to cleanliness, &c., apply in the manufacture of felt, lamp-black, and briquettes, with use of tar. Saturation of felt, and manufacture of tar plaster should be done in closed apparatus. In the production of lamp-black, even with a great number of soot chambers, there is escape of soot causing nuisance to workers and the neighbourhood. Complete avoidance of this seems to be difficult, so that measures for personal hygiene must be assured. In briquette factories it has been found useful to heat the tar by means of steam instead of by direct fire, which renders possible the use of a closed apparatus and mechanical stirring.
In the distillation of tar, during the first distillation period (first runnings) unpleasant and injurious gases containing ammonia and sulphur escape from the stills. These should (according to Leymann) be carried away through closed pipes branching off from the lower end of the running-off pipe, either into the furnace (in doing which a possible back flash of flame is to be guarded against) or be subjected to purification by lime or oxide of iron (similar to that in the case of illuminating gas) with a view to recovery of ammonia and sulphur. The lower end of the distillation pipes should be U-shaped so as to form a liquid seal—the pipes for the drawing off of the gases branching off before the curve. In the later stages of distillation risk can be checked by careful cooling and imperviousness of the apparatus.
Very unpleasant yellow fumes develop in great quantity when pitch is run off from the hot still. Hence hot pitch should not be run off into open pitch receptacles, but be cooled first in closed receptacles.
The crude products obtained by distillation (light oil, creosote oil) are subjected to purification consisting in treatment on the one hand with alkali and on the other with acid and followed by fractional distillation. In these processes injurious fumes may develop, therefore they must—as already mentioned—be carried on in closed vessels provided with means of escape for fumes and appliances for mechanical stirring; the fumes drawn off must be led into the chimney stack.
In the distillation of brown coal, of tar, and of resin, it is necessary, as in the distillation of coal tar, to insist above all on careful cooling and condensation, and thorough absorption of uncondensed gases in washing towers. Special precautionary rules are necessary to guard against the danger of entering tar stills for cleaning purposes. Such directions were approved in Great Britain in 1904 in view of accidents which occurred in this way:
Tar Distilling
The following directions[I] are approved by the Home Office and are applicable to factories in which is carried on the distillation of tar for the production of naphtha, light oil, creosote oil, and pitch.
1. During the process of cleaning, every tar still should be completely isolated from adjoining tar stills either by disconnecting the pipe leading from the swan neck to the condenser worm, or by disconnecting the waste gas pipe fixed to the worm end or receiver. Blank flanges should be inserted between the disconnections. In addition, the pit discharge pipe or cock at the bottom of the still should be disconnected.
2. Every tar still should be ventilated and allowed to cool before persons are allowed to enter.
3. Every tar still should be inspected by the foreman or other responsible person before any workman is allowed to enter.
4. The inspecting foreman on first entering any tar still or tank, and all persons employed in tar stills or tanks in which there are no cross stays or obstructions likely to cause entanglement, should be provided with a belt securely fastened round the body with a rope attached, the free end being left with two men outside whose sole duty should be to watch and draw out any person appearing to be affected by gas. The belt and rope should be adjusted and worn in such a manner that the wearer can be drawn up head foremost and through the manhole and not across it.
5. A bottle of compressed oxygen, with mouthpiece, should be kept at all times ready for use; and printed instructions as to the use of this bottle, and the method to be employed for resuscitation by means of artificial respiration should be kept constantly affixed. A draft of such instructions is appended.
6. A supply of suitable chemical respirators properly charged and in good condition should be kept ready for use in case of emergency arising from sulphuretted hydrogen or certain poisonous gases. (Granules of carbon saturated with a solution of caustic soda readily absorb sulphuretted hydrogen and may be used for charging respirators.)
7. The use of naked lights should be strictly prohibited in any portion of the works where gas of an inflammable nature is liable to be given off.
8. Each still should be provided with a proper safety valve, which should at all times be kept in efficient working condition.
Gassing
Symptoms.—The first symptoms are giddiness, weakness in the legs, and palpitation of the heart. If a man feels these he should at once move into fresh warm air, when he will quickly recover if slightly affected. He should avoid exposure to cold. He should not walk home too soon after recovery; any exertion is harmful.
First Aid.—Remove the patient into fresh warm air. Send for the oxygen apparatus. Send for a doctor. Begin artificial breathing at once if the patient is insensible and continue it for at least half-an-hour, or until natural breathing returns. Give oxygen[J] at the same time and continue it after natural breathing returns.
Artificial Breathing (Schäfer Method).—Place the patient face downwards as shown in the diagrams.
Kneel at the side of the patient and place your hands flat in the small of his back with thumbs nearly touching, and the fingers spread out on each side of the body over the lowest ribs (see Diagram 1).
Diagram 1
Then promote artificial breathing by leaning forward over the patient and, without violence, produce a firm, steady, downward pressure (see Diagram 2). Next release all pressure by swinging your body backwards without lifting your hands from the patient (see Diagram 1).
Diagram 2
Repeat this pressure and relaxation of pressure without any marked pause between the movements, about 15 times a minute, until breathing is established.
In my opinion as expressed in the general discussion, use of breathing apparatus (smoke helmets) with oxygen is strongly advisable; these implements must be put on before entering the still.
In creosoting wood, opening the apparatus and taking out the steeped wood should only be done when the apparatus is sufficiently cooled, as otherwise injurious fumes escape.
In heating asphalt unpleasant fumes arise which should be drawn off into a furnace, or absorbed by a condenser charged with oil (Leymann); open pans should be avoided, as injurious to workers.
Organic Dye-stuffs, Coal-Tar Colours.
(See also pp. [107-19] and [204-15])
The hygienic measures to be adopted for the prevention of industrial poisoning in coal-tar colour factories are chiefly concerned with the poisonous nature on the one hand of the raw material (benzene, toluene, &c.) and on the other of the intermediate products (nitrobenzene, aniline, toluidine, &c.) and the subsidiary substances (chlorine, acids, especially nitric acid, &c.,) used.
The most important measures are as follows:
In purifying the raw materials (benzene, &c.) the distillation requires to be done under effective cooling and in impervious apparatus. If injurious solvents are employed (such as pyridine in the production of anthracene) the manipulations should be performed in closed apparatus if possible, under negative pressure. The fumes exhausted should be carefully condensed by cooling or absorbed by a spray of water or oil.
In view of the poisonous nature of benzene, the apparatus, stills, receivers, tanks, tank waggons, &c., should only be entered for the purpose of cleaning or repairing after preliminary thorough removal of all residue of benzene, complete isolation from all similar apparatus near, and thorough ventilation. Workers entering the stills, &c., should always be equipped with breathing apparatus (smoke helmets) and with a supply of oxygen. Other aids, such as safety belts which are held by helpers, are not here advocated in view of the often sudden fatal poisoning, especially as the rescuer is easily induced to spring to the assistance of his unfortunate mate without the necessary equipment. The frequency of such accidents calls urgently for the use of breathing apparatus.
In the manufacture of diazo- and nitroso-compounds and generally in nitrating operations poisonous nitrous fumes are developed. By reduction in an acid solution, acid fumes and singularly pungent-smelling compounds can be given off. If reduction by means of tin is practised, the arsenic in the tin can cause evolution of the extremely poisonous arseniuretted hydrogen gas. In sulphonating, sulphur dioxide can develop; and sulphuretted hydrogen gas on heating with sulphur or sulphide of sodium.
All manipulations should take place in tightly closed-in apparatus provided with exhaust, and the gases drawn off should be absorbed or effectively carried away. In the case of many injurious gases it is not sufficient merely to conduct them into the flue; they ought to be condensed and got rid of. Thus acid fumes (nitrous fumes, sulphur dioxide, hydrochloric acid vapour, chlorine gas) are neutralised by water or milk of lime, or a solution of soda; ammonia or alcohol by water; sulphuretted hydrogen and arseniuretted hydrogen by lime and oxide of iron; aniline, &c., by dilute acids.
Production of nitrobenzene, by nitrating benzene requires to be done in closed apparatus, provided with mechanical agitators. In the subsequent separation of the nitrating acids from the resulting nitro-compounds, escape of vapourised nitro-compounds can scarcely be avoided even if closed apparatus is used. Provision, therefore, must be made for abundant ventilation of the workrooms. The reduction of the nitro-compounds (nitrobenzene, nitrotoluene) to aniline (toluidine) must similarly take place in closed agitating vessels. Introduction of the iron filings and sulphuric or hydrochloric acids, also the subsequent saturation with lime, and driving over of the aniline, &c., with steam, and collection of the distillate, must take place in completely closed apparatus. Nevertheless, escape of small quantities of aniline is very difficult to prevent unless ample ventilation is provided.
In the production of fuchsin by heating aniline hydrochloride (toluidine, red oil) with nitrobenzene (formerly arsenic acid) in closed vessels, furnished with mechanical stirring apparatus the aniline remaining unconverted after the melting escapes in the form of steam carrying aniline fumes, even with careful condensation, so that thorough ventilation and the other general measures for the protection of workers set forth on pp. [242 et seq.] are required.
Marked injury to health and distress to workers through acid fumes are sometimes caused by the denitration of the waste mixture of sulphuric and nitric acids in the nitrating process, that is, by the separation of nitric acid from the acid mixture. This denitration takes place usually in the Glover towers of the lead chamber system which is often associated with the manufacture of aniline. The mixed nitro-compounds of the waste acids, however, are often not completely condensed, but pass through the chambers and Gay-Lussac towers and escape into the air, whence arises the constant smell of nitrobenzene in aniline factories (Leymann). In the production of naphthylamine and recovery of chlorinated products, escaping chlorine should be led into chloride of lime chambers, hydrochloric acid fumes into towers to be absorbed by water and milk of lime or a solution of soda.
In aniline factories danger can scarcely be wholly avoided, as the workers, on the one hand, come into contact with poisonous substances, nitrobenzene, aniline, &c., and on the other hand, in spite of all technical hygienic measures, can hardly help breathing in some of the aniline. Apart from the technical regulations, therefore, there must be insistence on cleanliness of the workrooms, personal cleanliness on the part of the workers (washing, baths, working suits, cloak-rooms, &c.). Besides this, contact with aniline, nitrobenzene, &c., wetting of the body and clothes with these substances, and, especially spilling, splashing, and scattering these fluids must be carefully avoided. The workers require to be suitably instructed as to the symptoms of nitrobenzene and aniline poisoning, and the right steps to take, if poisoned. The oxygen apparatus must always be at hand, ready for use; the workers must be instructed how to use it. Further, workers, especially those newly employed, must be under supervision in order that assistance may be rendered them on the first signs of poisoning; medical assistance ought to be within easy reach. Workers also should know of the tendency of aniline to cause cancer of the bladder.
Precautions against the poisonous nitro-derivatives of benzene (nitrophenol, picric acid, &c.), which are in the form of poisonous dust, must take the form of entirely closed-in grinding and packing apparatus, or, at all events, removal of the dust at its source.
Among official regulations may be mentioned the Prussian Ministerial Edict, dated December 18, 1908, as to purification and storage of benzene, and further the Regulations dated December 13, 1907, and December 30, 1908, in force in Great Britain for the manufacture of nitro- and amido-derivatives of benzene, and the manufacture of explosives with use of dinitrobenzene or dinitrotoluene.
VI
PREVENTIVE REGULATIONS—THE EXTRACTION OF METALS (SMELTING WORK IN GENERAL)
Danger is incurred when the furnace leaks, a condition which generally occurs in the course of time, or if gases escape during the necessary manipulations through the working doors. This can be avoided by maintaining the walls in as air-tight a state as possible; but as very small leakages are almost unavoidable the best course is to so regulate the draught in the furnace (by means of fans) that a slight negative pressure always exists in it. Naturally, poisonous gases escaping from the furnace such as sulphur dioxide, carbonic oxide, carbon dioxide, and hydrocarbons require to be drawn away and rendered harmless. This can often be done by merely conducting them into the main flue. Gases containing carbonic oxide possess high heating capacity, and their escape can usually be prevented by suitable cupola bells. They can be led away in impervious conduits and utilised for heating purposes or for driving gas engines. Entering the flues for cleaning or repairing purposes is especially dangerous; and as it is difficult to isolate one portion entirely from another, such operations might well be carried on by persons equipped with breathing apparatus (smoke helmets or oxygen apparatus).
In roasting operations handwork can be largely replaced by furnaces worked mechanically. If the gases generated are rich in sulphur dioxide they can be utilised for the manufacture of sulphuric acid or for the production of liquid sulphur dioxide either directly or after concentration; if not, they must be rendered harmless by treatment with milk of lime in absorption towers. Other methods of rendering the sulphur dioxide (unsuited for manufacture of sulphuric acid) harmless depend on treatment with minerals containing calcium carbonate, or magnesium or aluminium hydrate, sodium sulphide, &c. Sometimes the sulphurous gases are led into blast furnaces containing oxide of iron and coal (so as to form sulphide of iron) or are absorbed by means of moist scraps of sheet iron or brown coal or peat briquettes.
Use of chlorine compounds in the extraction of metals from ores (silver, copper) causes evolution of chlorine and hydrochloric acid vapour. These should be dealt with in absorption towers. Metallic fumes are collected by suitable condensing arrangements. Flue dust is retained in flue dust chambers, but in the cleaning of such condensing flues and chambers danger to the workers is considerable and they should be equipped with respirators, working suits, &c. Personal hygiene must be insisted on.
Iron
(See also pp. [146-51])
In blast furnace work, industrial poisoning occurs mainly from escaping gases rich in carbonic oxide. They may also contain sulphur dioxide and cyanogen compounds. The high proportion of carbonic oxide, however, makes these gases valuable and serviceable, because of their great heating value. They are, therefore, now led away and utilised, the furnace being closed by a cupola bell only opened by means of a mechanical contrivance when charging is necessary; while this is being done the ignited blast furnace gases pour out, and the workers retire from the opening, so that danger to them is avoided. The construction of a blast furnace with a cupola bell can be seen in [fig. 29]. The blast furnace gases are conducted away by an opening in the side, and pass along special pipes to be utilised, after having gone through a purifying process mainly for the removal of flue dust, &c. The gases serve partly for the heating of the blast for the furnace itself, and partly for driving the gas engines which serve the electrical power apparatus, electric lighting, &c., in the works. Through the rational utilisation of the blast furnace gases, the workers are protected from their injurious action during the working of the furnace. Serious gas poisoning, however, occurs not infrequently to workers who have to enter the gas mains for cleaning purposes. Workers, therefore, should only be permitted to enter the flues, &c., a considerable time after the process has been stopped and after as complete and thorough a ventilation of the system as is possible.
Any portion of the gas system which is to undergo cleaning must be completely isolated. Ventilation is best effected by the introduction of compressed air. Thus a foundry (in the Duisburg district) has provided all its cellars and passages, through which gas pipes pass, and which must be entered during repairs, with compressed air pipes. It is, however, advisable that gas conduits should only be entered by workers equipped with breathing apparatus and oxygen supply. Naturally adequate instruction of workers and training in first aid are necessary, as well as a sufficient supply of oxygen in constant readiness.
Injurious gases can escape from the furnace during tapping and slag running; poisonous gases with a disagreeable odour, from presence of sulphuretted hydrogen, also arise in granulating the slag, that is, when the fluid slag is led into water for subsequent use in preparation of cement. These gases should be collected by hoods, and be carried away as far as possible.
In the manufacture of steel by the Bessemer or Thomas-Gilchrist process, the dark smoke arising out of the converter during the blowing operation should be drawn off (led into flues), as it is injurious to health. In the Martin furnaces poisoning may occur, especially when the gas flues are entered after cessation of work. In letting out the gas in order to stop the furnaces, the gas and air valves must first be closed and the outlet valves for gas be opened only after the pipes have been filled with steam. Steam is to be driven through until the pipes are quite free from gas, and the system only entered after it has become thoroughly cooled. If need arises for entering portions of the system while neighbouring parts are still filled with gas, the workers employed require to be provided with breathing apparatus and smoke helmets.
In the transport of ferro-silicon several cases of poisoning have occurred. Cautionary regulations, therefore, relating to this work have been found necessary.
Such directions are contained in the police regulations of the Prussian Minister of Trade and Industry respecting the transport on the Rhine of corrosive and poisonous substances (dated September 29, 1910).
It is prescribed: (1) that ferro-silicon be packed in strong watertight cases of wood or metal; (2) that on the cases be inscribed, legibly and indelibly, the notice ‘Ferro-silicon. To be kept dry! With care!’ (3) that the substance be delivered dry and in dry cases; (4) that the cases be stored in airy places on the deck of the ship in such a manner that they are protected from wet.
Further, care is to be taken that the storage on ships is done in such a way that possible damage to the material in which it is packed entails no risk. The harbour authorities where loading or landing takes place can deal with special cases as they think fit.
International regulation as to transport of ferro-silicon in the spirit of the above regulations would be most desirable in view of the oversea trade in this substance.[K]
Lead
(See also pp. [120-40] and [177-82])
For protection against lead poisoning, the most widely spread of the slow industrial poisonings, all those measures are of moment which we have described in our general discussion on protection against danger from poison in industries, both personal and general.
Personal hygiene, especially careful washing after work, prohibition of eating in workrooms, suitable working clothes, provision of cloak rooms, meal rooms, baths, &c., are important and effective measures for the protection of workers against industrial lead poisoning.
The worker should naturally be adequately instructed as to the risk. Appropriate printed notices are especially adapted for this purpose.
Further, selection of workers should be made under medical supervision. Workers who suffer from specific disease which, if associated with lead poisoning, may prove dangerous, should be excluded from all contact with lead. Among such illnesses must be reckoned tuberculosis in all its forms, alcoholism, epilepsy, tendency to mental disease (nervous disposition, hysteria, neurasthenia, &c.), rheumatism, and disease of the kidneys.
Overtime work undoubtedly increases risk; therefore working hours should be shortened as much as possible, and handwork replaced by machine work where possible. Young persons and women especially should be excluded from work in lead. Alternation of employment also is beneficial and essential in very dangerous lead work, because the poison accumulates in the body and only during intervals wherein absolutely no poison can be absorbed has it time to be eliminated.
Periodical medical examination by a surgeon is of great value with systematic entry of the results of examination in a health register. As bearing on this, early diagnosis is of the greatest importance, so that workers in whom the first signs of lead poisoning appear may at once be suspended or transferred to other work.
Lead workers should take suitable nourishing food and avoid particularly alcoholic excess.
When the danger is due to fumes or dust in the air the measures prescribed on pages 242-55 apply, particularly those which aim at keeping the workrooms and the air in the factories free of them by locally applied exhaust ventilation.
In order to replace or reduce the use of lead we strongly advocate the use of non-poisonous, or at any rate less poisonous, substances, where this can be done without technical difficulties, as, for instance, carborundum discs instead of lead in polishing of precious stones, leadless glaze in pottery for lead glaze (so far as this is possible, as to which see page 319), beds free of lead (in different industries) for lead beds. In a number of cases, however, such substitution is impracticable on technical grounds or can only partially be carried out, as, for example, in letterpress printing and in the paint and colour industry, in which the prohibition of lead has often been repeatedly urged. So far, unfortunately, it must be admitted that repeated attempts to find a non-poisonous substitute for lead colours, especially for white lead, of equal value technically, have not succeeded. Endeavours have been made to substitute for lead, zinc preparations (zinc white, lithopone, &c.), but hitherto (in regard to durability, opacity, &c.) with incomplete success.
Mention must be made of the measures based upon the relatively non-poisonous nature of lead sulphide. Lead sulphide is, in spite of various assertions to the contrary, practically non-poisonous; a fact attributable to its insolubility in water and weak acids. As lead sulphide is the only non-poisonous lead compound it is a duty to take advantage of this fact for purposes of lead prophylaxis.
Attempts with this end in view were made by the introduction of sulphur soaps in lead factories. Soaps containing in large quantity soluble alkaline sulphides convert lead compounds adhering to the skin into black lead sulphide. The lead compounds are in this way made harmless, and besides this the worker is impelled to remove the staining by washing. Such a sulphur soap has been brought into the market under the name of akremnin soap, but does not enjoy special popularity with the workmen on account of its unpleasant smell.
The struggle against the risks of lead employment has been going on ever since efforts for the protection of workers were commenced.
The International Association for Labour Legislation has made valuable inquiries in this direction. The question of lead poisoning had been repeatedly discussed by this Association and its branches in various countries. The International Labour Bureau also took up the issue and in 1906—supported by the Institute for General Welfare in Frankfurt a-M.—offered a prize for the best treatise on the prevention of industrial lead poisoning. The outcome of this competition was the volume compiled by Leymann, ‘Die Bekämpfung der Bleigefahr in der Industrie’ (published by Fischer, Jena, 1908).
In connection with the resolution adopted at the third Congress of the International Association for Labour Legislation the Union of Social Reform (as the German branch is called) addressed the Federal Council on the white lead question, the chief points insisted upon being the need for: (1) regulations for the house painting industry in pursuance of Section 120 of the Factory Code; (2) report by the Imperial Health Office on the practicability of substitutes for lead; (3) exclusion of lead colours from use in the painting of public buildings; and (4) treatment of lead poisoning by the State Insurance Office as an accident entitling to compensation.
These demands were supported by the central office of the Society for Promoting the Welfare of Workers, which had as far back as its seventh conference in 1898 occupied itself with the question of dangerous trades and especially, at its conference in 1905, taken up the subject of the protection of workers against industrial poisoning.
In Germany these efforts resulted in the passage of a number of Imperial Regulations for separate lead industries.
In other countries similar action was set on foot. In Austria, where the subject is of special importance in view of the part played by lead in the home industries, the Government undertook to improve the conditions in industries attended with risk of lead poisoning. For this purpose the Statistical Office of the Ministry of Commerce and Labour has, since 1904, carried out extensive inquiries into lead and zinc smelting works, paint and colour factories, the painting and varnishing trades, letterpress printing, and the ceramic industry. The results are contained in the volume ‘Lead Poisoning in Smelting Works and Industries Generally’ (published by Hölder, Vienna).
As in Germany and Austria, so also in Great Britain, France, Switzerland, Belgium, and the Netherlands, regulations in various lead industries were enforced after previous official inquiry and report.
A general code, however, affecting all lead industries has only been published in one or two states. And yet this would, in my opinion, be of very great practical value as it is hardly possible to regulate each single branch of industry.
In Germany the Regulations dated May 26, 1903, dealing with lead colours are certainly comprehensive, but relate primarily to paint factories, and are not, therefore, a general Order in the sense indicated. In Saxony the decree of June 27, 1901, made notification of lead poisoning compulsory, and in the subsequent decree of April 16, 1909, prescribed general measures against lead poisoning. In Switzerland single cantons have made general regulations. In France, by a decree dated April 23, 1908 (in pursuance of the general law of June 12, 1893), all industries attended with risk of lead poisoning were brought under Regulation.
We give the provisions of this interesting decree, as it is a good example of the kind of Regulations we have in mind.
Decree of the President of the French Republic (April 23, 1908) relating to certain industries in which lead is used
1. In the lead industries hereinafter mentioned, viz.: smelting, cupellation of argentiferous lead, manufacture of accumulators, glass-making, manufacture and use of lead enamels, manufacture of pottery, decoration of porcelain or faience, ceramic chromo-lithography, manufacture of lead alloys, oxides, salts and colours—employers, directors or managers are required, apart from the general measures prescribed by the Decree of 29 November, 1904, to take special measures for protection and health as set forth in the following sections.
2. Lead melting pots shall be erected in an airy place separated from the other workrooms.
Hoods or other means for the effectual removal of fumes shall be provided:—
(a) Over the openings for the run of lead and slag in lead smelting.
(b) Before the furnace doors in the manufacture of lead oxides.
(c) Above the pots for melting lead or its alloys, in the other industries enumerated in Section 1.
3. All work with oxides and other compounds of lead capable of producing dust shall be done as far as possible when in a damp condition.
When this work cannot be done in the presence of water or other liquid, it shall be carried out by mechanical means, in covered air-tight apparatus.
If it is impossible to conform to the requirements of either of the first two paragraphs of this section, the work shall be done under a strong draught so arranged that the harmful products may be intercepted by apparatus suitably placed.
Finally, if none of these systems is possible the workmen shall be supplied with respirators.
4. Oxides and other compounds of lead, whether dry or damp, in suspension or solution, shall not be handled with the bare hand. The employer shall at his own expense provide the workers in these operations with either gloves made of impervious material such as indiarubber, or suitable appliances, and shall cause them to be kept in good repair and frequently cleaned.
5. Tables on which these products are handled shall be covered with some impervious material, kept in a perfectly water-tight condition.
The same requirement applies to the floors of the workrooms, which shall also be kept damp.
The floor shall be slightly sloped towards a water-tight receptacle for collecting the lead substances which are washed down.
The work shall be so arranged that there shall be no splashing. The tables, floors and walls shall be washed at least once a week.
6. Without prejudice to the requirements of section 3, the grinding and mixing of lead products, and the use of them in dusting shall be effected in special places with active ventilation.
If the materials cannot be damped, the workers shall be provided with respirators.
7. Pottery shall not be dipped with bare hands in solutions containing litharge, red lead, galena or white lead in suspension.
8. No food or drink shall be brought into the works.
9. Employers shall, at their own expense, provide and maintain for the use of the workers, overalls or clothing for use during work only, in addition to gloves and respirators.
10. In a part of the building separated from the workrooms, there shall be provided for the use of the workers exposed to lead dust or fumes, a cloak room and lavatory kept in good order, provided with basins or taps in sufficient number, a plentiful supply of water, soap and a towel for each worker replaced at least once a week.
The cloak rooms shall be provided with cupboards or drawers with locks or padlocks, the ordinary clothing being kept apart from the working clothes.
11. A warm bath or shower bath shall be provided each week for the workers exposed to lead dust or fumes.
A warm bath or shower bath shall be provided every day after work, for each worker employed, either in emptying or cleaning the condensing chambers and flues, in repairing furnaces in lead works, in carrying lead corrosions from the beds in white lead factories, in packing red lead, in grinding lead enamels and in dry dusting.
12. Employers are required to exhibit, in a conspicuous position in the works, regulations imposing on the workers the following obligations:—
To use the appliances, gloves, respirators, and working clothes placed at their disposal.
Not to bring into the works either food or drink.
To pay great care, before each meal, to the cleanliness of the mouth, nose, and hands.
To take the baths weekly or daily as provided in section 11.
13. The Minister of Labour may, by Order made with the advice of the Consultative Committee for Arts and Manufactures, exempt an establishment for a specified period, from all or part of the requirements of Regs. 2ᵃ, 2ᵇ, 2ᶜ, 5² and 6¹ in any case where it is found that observance of these requirements is practically impossible, and that the health and safety of the workers are assured by conditions at least equivalent to those prescribed in the present Order.
14. Subject to additional postponements which may be granted by the Minister in pursuance of Section 6 of the Act of 12th June, 1893 (as amended by that of 11th July, 1903), the delay required for the carrying out of the alterations necessitated by the present Decree is limited to one year from the date of its publication.
15. The Ministry of Labour is charged with the administration of this Decree.
This decree was supplemented by further noteworthy additions requiring medical supervision in lead industries as follows:
Decree of December 28, 1909, Organising Medical Service in Industries Exposing the Workers to Risk of Lead Poisoning
1. In premises in which the processes enumerated in Regulation 1 of the Decree of April 23, 1908, are carried on medical attendance as prescribed below shall be provided.
2. A surgeon appointed by the occupier shall examine the workers and enter the results of examination required in Regulations 3 and 4. The examinations shall be paid for by the occupier.
3. No person shall be employed in work mentioned in Regulation 1 of the Decree of April 23, 1908, without a certificate from the surgeon stating that he is free from symptoms of lead poisoning and of illness which might render him specially susceptible.
4. No worker shall remain at the same employment unless the certificate is renewed one month after commencement of employment and subsequently at quarterly intervals.
In addition to the periodical examination the occupier shall give an order on the surgeon to every workman declaring himself to be ill from his employment or who desires to undergo medical examination.
5. A special Register open to the Factory Inspector shall be kept containing the following particulars of each worker:
(1) Dates and duration of absence on account of illness of any kind;
(2) Dates of medical certificates for such illness, the notes made by the surgeon and the name of the surgeon furnishing them;
(3) Instructions given by the appointed surgeon in pursuance of Regulations 3 and 4 above.
Lead Smelting Works
(See also pp. [122-31])
As the fumes in lead smelting works contain a high proportion of lead, all apparatus, especially furnaces and working doors, should be provided with efficient exhaust ventilation and all flues, furnaces, and other apparatus be as airtight as possible. Where lead dust is created exhaust ventilation locally applied is necessary. Two of the most important preventive measures are personal cleanliness and alternation of employment. Dust arising in the furnaces and borne along by the furnace gases together with arsenical fumes and dust must be deposited in flues or chambers.
In view of the importance of proper instruction of smelters as regards the danger we quote the warning note prepared by the Institute for Industrial Hygiene, Frankfurt a.-M., which deserves wide circulation.
Lead Leaflet for Smelters
How does Lead Poisoning arise?
The danger of lead poisoning in lead, spelter and other smelting premises can be avoided if due care is observed.
Lead poisoning occurs when lead enters the system. This takes place by breathing dust and fume containing lead, or by eating and drinking, smoking, snuff taking and tobacco chewing if food or tobacco is taken into the mouth with dirty hands and dirty face and beard.
No one is immune from lead. Lead accumulates in the body of careless persons and he who is not sick to-day can be so to-morrow or after weeks or months.
How can Plumbism be avoided?
All smelters must observe cleanliness. In this respect they should see to the following points:
1. It is to their interest to see that the exhaust ventilation is kept in order and that the Special Rules or Regulations are exactly followed. Further, special clothing should be worn, the mouth and nose should be covered, and the floors sprinkled.
2. It is especially important that in intervals and at the close of work the mouth, face, beard, and hands should be carefully cleaned. Food should not be eaten or the premises left without putting on fresh clothes and thoroughly washing or, still better, bathing. When drinking, the edge of the drinking glass should not be fingered with dirty hands. Especially important is it that the teeth should be cleaned and the mouth washed out.
3. During work smoking, snuff taking, and tobacco chewing, which invariably convey lead into the mouth, should be given up, as it is impossible to prevent the hands getting contaminated with lead. Lighting the pipe with glowing lead ashes is in the highest degree dangerous from the risk of inhaling lead fume. The body must be strengthened to withstand the action of lead. Moderation in drinking, especially avoidance of spirits, should be observed. Alcoholic subjects succumb to lead poisoning much more readily than the temperate.
Food should be abundant and rich in fat, for example milk and bacon. Thick soups are excellent before work. Work should never be begun on an empty stomach. And lastly as much fresh air as possible. Walking, athletics, work in the garden and field will help to keep off many an attack. If anyone thinks that he is suffering from lead poisoning he should at once in his own and his family’s interest see the doctor of his sick club.
The following are the
German Imperial Regulations for Lead Smelting Works, dated June 16, 1905
General Regulations
1. Workrooms in which lead ores are roasted, sintered, or smelted, pig lead produced and submitted to further treatment, distillation of rich lead (bullion cupellation) litharge, red lead, or other oxides of lead prepared, ground or sieved, stored or packed, or zinc skimmings distilled, shall be roomy, high, and so arranged that a sufficient constant exchange of air takes place. They shall be provided with a level and solid floor to allow of easy removal of dust by a moist method.
The walls shall be smooth so as to prevent collection of dust; they shall be either washed down or lime washed at least once a year.
Provided that this shall not apply in the case of calcining sheds with wooden walls.
2. An abundant supply of good drinking water, protected against contamination from dust, shall be provided for the workers on the furnaces and smelting pots, and in such close proximity to them, that they can obtain it at any time without having to go into the open air.
Arrangements for sprinkling the floors shall be provided near the furnaces. The floors of the rooms mentioned in paragraph 1 shall be wet cleansed at least once daily.
3. Prepared (i.e. concentrated) lead ores and leady smelting products, unless moist, shall not be crushed except in an apparatus so arranged as to prevent as far as possible penetration of dust into the workrooms.
Provided that this shall not apply to calcined material from converters.
Sacks in which lead ores and materials containing lead have been packed shall not be freed from dust and cleaned except in a dust-proof apparatus or by washing.
4. Materials containing lead for charging the blast-furnaces, if they are oxides and form dust, shall be damped before they are mixed with other materials, stocked on the feeding floor, or charged into the blast-furnaces.
Provided that this shall not apply in the case of calcined material from converters.
5. Dust, gases, and lead fumes, escaping from furnaces, and converters, tapping spouts, tapping pots, drain sump, slag pots, slag cars, or slag channels, and from glowing residues taken from the furnaces, shall be caught as near as possible to the point of origin and removed harmlessly.
Dust collecting chambers, flues, as well as furnaces which have been ‘blown down,’ shall not be entered by workmen unless sufficiently cooled and ventilated.
Special Regulations for such parts of a factory where lead colours are prepared
6. In grinding, sieving and packing dry leady materials, in charging, and emptying litharge and red lead furnaces, in collecting the red lead and similar operations in which leady dust is developed, exhaust arrangements shall be provided for preventing the entrance of dust into the workrooms.
7. Apparatus producing leady dust, if their construction and manner of use does not effectually prevent evolution of dust, shall have all cracks protected by thick layers of felt or woollen material, or by similar means, so as to prevent the entrance of dust into the workrooms.
Apparatus of this character shall be provided with arrangements for preventing compression of air in them. They shall only be opened when the dust in them shall have completely settled, and they are absolutely cool.
Special arrangements in force for the distillation of zinc skimmings
8. Proposed new furnaces for the distillation of zinc skimmings (for which according to pars. 16 and 25 of the Industrial Code a special permission is required) shall be so arranged that (1) there shall be at least a clear space of 10 feet in front of the charging opening; (2) any passages under the distillation rooms shall be roomy, at least 11½ feet high in the centre, light and airy.
9. Dust, gases, and fumes arising from the zinc skimmings distillation furnaces shall be collected as near as possible to the point of origin, and carried outside the smelting room.
The entrance of gases from the fires into the smelting room shall be prevented as far as possible by suitable arrangements for drawing them off.
10. Sieving and packing of by-products obtained in the distillation of zinc skimmings (poussière, flue dust) shall not be done except in a special room separated from the other workrooms, and complying with the requirements of Reg. 1.
Sieving shall only be done in an apparatus so constructed that dust shall not escape.
Employment of workers.
11. Women and young persons shall not be employed or permitted in rooms mentioned in Reg. 1, in flue dust chambers, or dust flues, or in the removal of flue dust.
12. No person shall be newly employed in rooms mentioned in Reg. 1, in flue dust chambers, or dust flues, or in the transport of flue dust, without a certificate of fitness from the surgeon appointed by the higher authorities.
These certificates shall be collected and shown to the Factory Inspector and Appointed Surgeon on request.
13. No person shall be employed in charging blast furnaces, apart from mere labouring work on the floors, for more than eight hours daily. The same shall apply in the case of workmen employed in the inside of furnaces when cool, or in emptying flue dust chambers, or dust flues which contain wet flue dust.
No person shall be employed in cleaning out, from inside, flue dust chambers, or dust flues containing dry flue dust for more than four hours daily; and including emptying and work of transport of this kind altogether no longer than eight hours daily.
Other workers in rooms specified in Reg. 1 shall not work more than 10 hours in 24, exclusive of mealtimes.
Exception to this is allowed in the case of those workers who are employed for the purpose of a weekly change of shift, and for whom exception as to Sunday employment is permitted by Imperial Decree.
Clothing, overalls, lavatory accommodation, &c.
14. The occupier shall provide for all persons employed in cleaning out flue dust chambers, dust flues, repairing of cooled furnaces, grinding, sieving and packing of litharge, red lead, or other lead colours, complete suits of working clothes, including caps and respirators.
15. Work with lead salts in solution shall not be done except by workers who either grease their hands or are provided with impermeable gloves.
16. The suit of clothes, or overalls, provided in Regs. 14 and 15, respirators and gloves, shall be provided in sufficient amount and in proper condition. The occupier shall see that they are always suitable for their purpose, and are not worn except by those workers for whom they are intended; and that they, at stated intervals (the overalls at least once a week, the respirators and gloves prior to use), are cleaned, and during the time that they are not in use are kept in a place specially reserved for each article.
17. A lavatory and cloak room shall be provided for the use of the workmen in a part of the building free from dust. Separate from it there shall be a dining-room. These rooms must be kept free from dust and be warmed during the winter.
In a suitable place provision shall be made for warming the workers’ food.
Water, soap, and towels, and arrangements for keeping separate the overalls from other clothing taken off before the commencement of work shall be provided in sufficient amount in the lavatory and cloak room.
The occupier shall afford opportunity for persons engaged in cleaning out flue dust chambers, dust flues, and the cooled furnaces, to take a bath daily after the end of the work, and for those handling oxides of lead, at least once a week, during working hours inside the works. The bathroom shall be warmed during the winter.
18. The occupier shall place the supervision of the health of the workers in the hands of a surgeon, appointed by the higher authorities for this purpose, whose name shall be sent to the Inspector of Factories. The surgeon shall examine the workers at least once a month in the factory, with a view to the detection of symptoms of lead poisoning.
The occupier shall not employ persons suspected by the surgeon of having contracted lead poisoning in the processes mentioned in Reg. 1 or in cleaning out flue dust chambers, dust flues, or furnaces when cold, or transport of the flue dust, until they are quite well. Those who appear peculiarly susceptible shall be permanently suspended from working in these processes.
19. The Health Register shall be shown to the Factory Inspector and Appointed Surgeon on demand. (Similar to Reg. 15 of Spelter Regulations.)
20. The occupier shall require the workers to subscribe to the following conditions:—
(1) Food must not be taken into the workrooms. Meals may only be taken outside the workrooms.
(2) Workmen must only enter the meal room to take their meals or leave the factory, after they have taken off their overalls and carefully washed their face and hands.
(3) Workmen must use the overalls, respirators and gloves in those workrooms and for the particular processes for which they are given them.
(4) Cigar and cigarette smoking during work is forbidden.
(5) A bath in the factory must be taken every day at the close of their work by those engaged in the emptying and cleaning of flue dust chambers, flues, and furnaces when cold, and by those employed on oxides of lead once a week.
Provided that this shall not apply in the case of workmen exempted by the appointed surgeon.
Workers contravening these orders will be liable to dismissal without further notice.
21. In every workroom, as well as in the cloak room and meal room, there shall be posted up by the occupier, in a conspicuous place and in clear characters, a notice of these regulations.
The occupier is responsible for seeing that the requirement of Reg. 20 (1) is obeyed. He shall make a manager or foreman responsible for the precise carrying out of Reg. 20 (1) (2) and (5). The person thus made responsible shall see to the carrying out of the regulations and for the exercise of necessary care as prescribed in par. 151 of the Factory Act.
22. No work in a lead smelting works shall be commenced until notice of its erection has been sent to the Factory Inspector. After receipt of the notice he shall personally visit to see whether the arrangements are in accordance with these regulations.
23. These regulations come into force on 1st January, 1906. Where structural alterations are necessary for the carrying out of Regs. 1, 5 (1), 6, 9, 10 and 17, the higher authorities may allow an extension of time to a date not later than January 1st, 1908.
If it seems necessary on strong grounds of public interest, the Council (Bundesrath) may extend the time in particular works until 1st January, 1913, and until then allow exceptions from the regulations as regards Reg. 13 (1) and (2).
Accumulator Factories
[Dr. Rambousek gives a very brief synopsis of the German Imperial Regulations in force for this industry and mentions that in Great Britain the Regulations of the Secretary of State dated 1903 are similar. We have printed these, as the code is fairly representative of the English Regulations for (1) smelting of metals; (2) paints and colours; (3) tinning of hollow ware; (4) yarn dyed with chromate of lead; (5) vitreous enamelling; and the special rules for (6) white lead and (7) earthenware:
Regulations dated November 21, 1903, made by the Secretary of State for the Manufacture of Electric Accumulators
Whereas the manufacture of electric accumulators has been certified in pursuance of Section 79 of the Factory and Workshop Act, 1901, to be dangerous;
I hereby, in pursuance of the powers conferred on me by that Act, make the following regulations, and direct that they shall apply to all factories and workshops or parts thereof in which electric accumulators are manufactured.
Definitions.—In these Regulations ‘lead process’ means pasting, casting, lead burning, or any work involving contact with dry compounds of lead.
Any approval given by the Chief Inspector of Factories in pursuance of these Regulations shall be given in writing, and may at any time be revoked by notice in writing signed by him.
Duties of Occupier
1. Ventilation.—Every room in which casting, pasting or lead burning is carried on shall contain at least 500 cubic feet of air space for each person employed therein, and in computing this air space, no height above 14 feet shall be taken into account.
These rooms and that in which the plates are formed shall be capable of through ventilation. They shall be provided with windows made to open.
2. Separation of processes.—Each of the following processes shall be carried on in such manner and under such conditions as to secure effectual separation from one another and from any other process:
(a) Manipulation of dry compounds of lead;
(b) Pasting;
(c) Formation, and lead burning necessarily carried on therewith;
(d.) Melting down of old plates.
Provided that manipulation of dry compounds of lead carried on as in Regulation 5 (b) need not be separated from pasting.
3. Floors.—The floors of the rooms in which manipulation of dry compounds of lead or pasting is carried on shall be of cement or similar impervious material, and shall be kept constantly moist while work is being done.
The floors of these rooms shall be washed with a hose pipe daily.
4. Melting pots.—Every melting pot shall be covered with a hood and shaft so arranged as to remove the fumes and hot air from the workrooms.
Lead ashes and old plates shall be kept in receptacles especially provided for the purpose.
5. Manipulation of dry compounds of lead.—Manipulation of dry compounds of lead in the mixing of the paste or other processes, shall not be done except (a) in an apparatus so closed, or so arranged with an exhaust draught, as to prevent the escape of dust into the work room: or (b) at a bench provided with (1) efficient exhaust draught and air guide so arranged as to draw the dust away from the worker, and (2) a grating on which each receptacle of the compound of lead in use at the time shall stand.
6. Covering of benches.—The benches at which pasting is done shall be covered with sheet lead or other impervious material, and shall have raised edges.
7. Prohibition of employment.—No woman, young person, or child shall be employed in the manipulation of dry compounds of lead or in pasting.
8. (a) Appointed Surgeon.—A duly qualified medical practitioner (in these Regulations referred to as the ‘Appointed Surgeon’) who may be the Certifying Surgeon, shall be appointed by the occupier, such appointment unless held by the Certifying Surgeon to be subject to the approval of the Chief Inspector of Factories.
(b) Medical examination.—Every person employed in a lead process shall be examined once a month by the Appointed Surgeon, who shall have power to suspend from employment in any lead process.
(c) No person after such suspension shall be employed in a lead process without written sanction entered in the Health Register by the Appointed Surgeon. It shall be sufficient compliance with this regulation for a written certificate to be given by the Appointed Surgeon and attached to the Health Register, such certificate to be replaced by a proper entry in the Health Register at the Appointed Surgeon’s next visit.
(d) Health Register.—A Health Register in a form approved by the Chief Inspector of Factories shall be kept, and shall contain a list of all persons employed in lead processes. The Appointed Surgeon will enter in the Health Register the dates and results of his examinations of the persons employed and particulars of any directions given by him. He shall on a prescribed form furnish to the Chief Inspector of Factories on the 1st day of January in each year a list of the persons suspended by him during the previous year, the cause and duration of such suspension, and the number of examinations made.
The Health Register shall be produced at any time when required by H.M. Inspectors of Factories or by the Certifying Surgeon or by the Appointed Surgeon.
9. Overalls.—Overalls shall be provided for all persons employed in manipulating dry compounds of lead or in pasting.
The overalls shall be washed or renewed once every week.
10. Cloak and dining rooms.—The occupier shall provide and maintain:
(a) a cloak room in which workers can deposit clothing put off during working hours. Separate and suitable arrangements shall be made for the storage of the overalls required in Regulation 9.
(b) a dining room unless the factory is closed during meal hours.
11. Food, &c.—No person shall be allowed to introduce, keep, prepare or partake of any food, drink, or tobacco, in any room in which a lead process is carried on. Suitable provision shall be made for the deposit of food brought by the workers.
This regulation shall not apply to any sanitary drink provided by the occupier and approved by the Appointed Surgeon.
12. Washing.—The occupier shall provide and maintain for the use of the persons employed in lead processes a lavatory, with soap, nail brushes, towels, and at least one lavatory basin for every five such persons. Each such basin shall be provided with a waste pipe, or the basins shall be placed on a trough fitted with a waste pipe. There shall be a constant supply of hot and cold water laid on to each basin.
Or, in the place of basins the occupier shall provide and maintain troughs of enamel or similar smooth impervious material, in good repair, of a total length of two feet for every five persons employed, fitted with waste pipes, and without plugs, with a sufficient supply of warm water constantly available.
The lavatory shall be kept thoroughly cleansed and shall be supplied with a sufficient quantity of clean towels once every day.
13. Before each meal and before the end of the day’s work, at least ten minutes, in addition to the regular meal times, shall be allowed for washing to each person who has been employed in the manipulation of dry compounds of lead or in pasting.
Provided that if the lavatory accommodation specially reserved for such persons exceeds that required by Regulation 12, the time allowance may be proportionately reduced, and that if there be one basin or two feet of trough for each such person this Regulation shall not apply.
14. Baths.—Sufficient bath accommodation shall be provided for all persons engaged in the manipulation of dry compounds of lead or in pasting, with hot and cold water laid on, and a sufficient supply of soap and towels.
This rule shall not apply if in consideration of the special circumstances of any particular case, the Chief Inspector of Factories approves the use of local public baths when conveniently near, under the conditions (if any) named in such approval.
15. Cleaning.—The floors and benches of each workroom shall be thoroughly cleansed daily, at a time when no other work is being carried on in the room.
Duties of Persons Employed
16. Medical examination.—All persons employed in lead processes shall present themselves at the appointed times for examination by the Appointed Surgeon as provided in Regulation 8.
No person after suspension shall work in a lead process, in any factory or workshop in which electric accumulators are manufactured, without written sanction entered in the Health Register by the Appointed Surgeon.
17. Overalls.—Every person employed in the manipulation of dry compounds of lead or in pasting shall wear the overalls provided under Regulation 9. The overalls, when not being worn, and clothing put off during working hours, shall be deposited in the places provided under Regulation 10.
18. Food, &c.—No person shall introduce, keep, prepare, or partake of any food, drink (other than any sanitary drink provided by the occupier and approved by the Appointed Surgeon), or tobacco in any room in which a lead process is carried on.
19. Washing.—No person employed in a lead process shall leave the premises or partake of meals without previously and carefully cleaning and washing the hands.
20. Baths.—Every person employed in the manipulation of dry compounds of lead or in pasting shall take a bath at least once a week.
21. Interference with safety appliances.—No person shall in any way interfere, without the concurrence of the occupier or manager, with the means and appliances provided for the removal of the dust or fumes, and for the carrying out of these Regulations.
These Regulations shall come into force on the 1st day of January, 1904.
White Lead
(See also pp. [131] and [132])
In the manufacture of white lead processes which create dust are specially dangerous, namely, emptying the corrosion chambers, drying and grinding, transport of the material in the form of powder, and packing. The following measures are called for: emptying the chambers should only be done by men wearing respirators or equipped with breathing helmets after preliminary damping of the corrosions by means of a spray. Use of a vacuum cleaning apparatus suggests itself. Drying should be done as far as possible in stoves charged mechanically, the temperature in which can be watched from the outside; grinding must be done in closed and ventilated mills; transport of the dried material should be effected by mechanical means or vacuum apparatus, and packing should be done in mechanical packing machines. Further, cleanliness and strict discipline are essential. Alternation of employment is advisable. The question of substitutes for white lead is referred to on p. [293].
Manufacture of red lead calls for precisely similar preventive measures. Charging and emptying the oxidising furnaces should be done under efficient exhaust ventilation. Conveyance, sifting, and grinding of the cooled material requires to be done in the same way as has been described for white lead.
In the production of chrome colours (lead chromates) besides the danger from lead the injurious action of chrome has to be borne in mind.
Regulations for white lead factories have been made in Germany, Belgium, and Great Britain. We give below the German Imperial Regulations dated May 26, 1903.
Regulations for Manufacture of Lead Colours and Lead Products
(1) The following regulations apply to all premises in which lead colours or other chemical lead products (white lead, chromate of lead, masicot, litharge, minium, peroxide of lead, Cassel yellow, English yellow, Naples yellow, lead iodide, lead acetate, &c., are manufactured), or in which mixtures of lead are prepared as the principal or as a subsidiary business. They shall not apply to lead smelting works, even though processes named in paragraph (1) are carried on.
Neither shall they apply to workplaces in which manufactured colours are intimately mixed or ground in oil or varnish in connection with another industry.
(2) The workrooms in which the materials mentioned in paragraph 1 are prepared or packed shall be roomy, lofty, and so arranged that sufficient and constant exchange of air can take place.
They shall be provided with a solid and smooth floor permitting of easy removal of dust by a moist method. The floor, unless for purposes of manufacture, shall be kept constantly wet, and shall be wet cleansed at least once daily.
The walls, when not of a smooth washable surface or painted with oil, shall be whitewashed at least once a year.
(3) The entrance of lead dust, or fumes, into the workrooms shall be prevented by suitable means as far as possible. Rooms which cannot be thus protected must be so separated from other rooms that neither dust nor fumes can enter them.
(4) Lead melting pots shall be covered with a hood and shaft communicating directly or by a chimney with the open air.
(8)[L] Grinding, sieving, and packing dry lead compounds, emptying litharge and minium furnaces, and other operations in which lead dust is generated, shall not be done except under an exhaust draught, or other efficient means for preventing the entrance of dust into the workrooms.
In the packing of colours containing only a little lead, in small amounts, or in small packages for retail purposes, exception to these regulations can be allowed by the higher authorities.
(9) Machines generating lead dust and not efficiently protected by their construction or method of use against the escape of dust, shall have all cracks occluded by means of thick layers of felt or similar material, so as to prevent the entrance of dust into the workrooms.
Machines of this kind shall be provided with arrangements preventing pressure of the air inside. They shall not be opened until they are cool, and until the dust generated has settled.
(10) Women shall not be employed in factories in which the colours specified in paragraph (1) are prepared except in work which does not expose them to the action of lead dust or fumes. Young persons shall not be employed nor be allowed on the premises in factories concerned exclusively or in great part with the preparation of lead colours or other lead compounds.
(11) No person shall be employed in rooms where the processes specified in paragraph (1) are carried on who is not provided with a certificate from a qualified surgeon stating that he is physically fit and free from disease of the lungs, kidneys, and stomach, and that he is not addicted to alcohol. This certificate shall be kept and produced on demand to the Factory Inspector or Appointed Surgeon.
(12) No person shall be employed in packing lead colours or mixtures containing lead or other lead compounds in a dry state, or with the coopering of the filled casks for more than eight hours daily. This regulation shall not apply where the packing machines are provided with effectual exhaust arrangements, or so constructed and used as effectually to prevent the escape of dust.
No person under 18 years of age shall be employed in the process mentioned in the above paragraph, but exception can be allowed in the packing of colours containing lead in small amount, or in small packages for retail purposes, on application to the higher authorities.
For the rest, no person coming into contact with lead or lead compounds shall be employed for more than 10 hours within the space of 24 hours.
(13) The occupier shall provide overalls and head-coverings for all persons coming into contact with lead or lead compounds, and suitable footwear for those emptying the oxidising chambers.
(14) The occupier shall not allow work involving exposure to dust to be performed except by workers provided with respirators or moist sponges covering the nose and mouth.
(15) The occupier shall not allow work involving contact with soluble salts of lead to be done except by workers provided with waterproof gloves or by those whose hands have previously been smeared with vaseline.
(16) The occupier shall provide the overalls, respirators, &c., mentioned in paragraphs (13) (14) and (15) for each one of the workers in sufficient number and in good condition. He shall take care that they are used only by the workers to whom they are severally assigned, and that in the intervals of work and during the time when they are not in use they shall be kept in their appointed place. Overalls shall be washed every week, and the respirators, sponges, and gloves before each time that they are used.
(17) Lavatories and cloak rooms, and, separate from these, a mess room, shall be provided for the workers coming into contact with lead or lead compounds in a part of the works free from dust. These rooms shall be kept in a cleanly condition, free from dust, and shall be heated during the cold seasons. In the meal room or in some other suitable place there shall be means for warming food. The lavatories and cloak rooms shall be provided with water, vessels for rinsing the mouth, nail brushes for cleaning the hands and nails, soap, and towels. Arrangements shall also be made for keeping separate clothes worn during work from these taken off before the commencement of work. The occupier shall give facilities for all persons employed in emptying the oxidizing chambers to have a warm bath daily after the end of the work, and for those persons coming into contact with lead or lead compounds, twice weekly. The time for this shall be during the hours of work, and in the cold season the bath room, which must be on the factory premises, shall be heated.
(18) The occupier shall appoint a duly qualified medical practitioner, whose name shall be sent to the Inspector of Factories and to the Health Authority. He shall examine the workers at least twice every month with a view to the detection of symptoms of lead poisoning. The occupier shall not employ workers suspected of symptoms of lead poisoning in occupations exposing them to lead or lead compounds until they have completely recovered. Those who appear peculiarly susceptible shall be suspended permanently from work.
(19) The occupier shall keep a book, or make some official responsible for its keeping, recording any change in the personnel employed in lead or lead compounds and as to their state of health. He shall be responsible for the completeness and correctness of the entries except those made by the surgeon.
The remaining regulations as to entries in the Health Register, &c., are similar to those already given in the Regulations for lead smelting works on p. [300].
Use of Lead Colours
(See also pp. [132-4])
As explained on pp. [132-134] use of lead in the painting and varnishing trades frequently causes lead poisoning. This has led to regulations in various countries having for their object partly hygienic measures and partly also limitation of colours containing lead, such as prohibition of the use of lead paints in the interior of buildings or in the painting of public buildings and of ships, &c.
The details of such regulations are seen in the German Imperial Regulations dated June 27, 1905:
Order of the Imperial Chancellor relating to the Processes of Painting, Distempering, Whitewashing, Plastering, or Varnishing. June 27, 1906
I.—Regulations for carrying on the Industries of Painting, Distempering, Whitewashing, Plastering, or Varnishing.
Regulation 1.—In the processes of crushing, blending, mixing, and otherwise preparing white lead, other lead colours, or mixtures thereof with other substances in a dry state, the workers shall not directly handle pigment containing lead, and shall be adequately protected against the dust arising therefrom.
Regulation 2.—The process of grinding white lead with oil or varnish shall not be done by hand, but entirely by mechanical means, and in vessels so constructed that even in the process of charging them with white lead no dust shall escape into places where work is carried on.
This provision shall apply to other lead colours. Provided that such lead colours may be ground by hand by male workers over 18 years of age, if not more than one kilogram of red lead and 100 grains of other lead colours are ground by any one worker on one day.
Regulation 3.—The processes of rubbing-down and pumice-stoning dry coats of oil-colour or stopping not clearly free from lead shall not be done except after damping.
All débris produced by rubbing down and pumice-stoning shall be removed before it becomes dry.
Regulation 4.—The employer shall see that every worker who handles lead colours or mixtures thereof is provided with, and wears, during working hours, a painter’s overall or other complete suit of working clothes.
Regulation 5.—There shall be provided for all workers engaged in processes of painting, distempering, whitewashing, plastering, or varnishing, in which lead colours are used, washing utensils, nail brushes, soap and towels. If such processes are carried on in a new building or in a workshop, provision shall be made for the workers to wash in a place protected from frost, and to store their clothing in a clean place.
Regulation 6.—The employer shall inform workers, who handle lead colours or mixtures thereof, of the danger to health to which they are exposed, and shall hand them, at the commencement of employment, a copy of the accompanying leaflet (not printed with this edition), if they are not already provided with it, and also a copy of these Regulations.
II.—Regulations for the Processes of Painting, Distempering, Whitewashing, Plastering, or Varnishing when carried on in connection with another Industry.
Regulation 7.—The provisions of paragraph 6 shall apply to the employment of workers connected with another industry who are constantly or principally employed in the processes of painting, distempering, whitewashing, plastering, or varnishing, and who use, otherwise than occasionally, lead colours or mixtures thereof. The provisions of paragraphs 8-11 shall also apply if such employment is carried on in a factory or shipbuilding yard.
Regulation 8.—Special accommodation for washing and for dressing shall be provided for the workers, which accommodation shall be kept clean, heated in cold weather, and furnished with conveniences for the storage of clothing.
Regulation 9.—The employer shall issue regulations which shall be binding on the workers, and shall contain the following provisions for such workers as handle lead colour and mixtures thereof:
1. Workers shall not consume spirits in any place where work is carried on.
2. Workers shall not partake of food or drink, or leave the place of employment until they have put off their working clothes and carefully washed their hands.
3. Workers, when engaged in processes specified by the employer, shall wear working clothes.
4. Smoking cigars and cigarettes is prohibited during work.
Furthermore, it shall be set forth in the regulations that workers who, in spite of reiterated warning, contravene the foregoing provisions may be dismissed before the expiration of their contract without notice. If a code of regulations has been issued for the industry (par. 134a of the G.O.) the above indicated provisions shall be incorporated in the said code.
Regulation 10.—The employer shall entrust the supervision of the workers’ health to a duly qualified medical man approved of by the public authority, and notified to the factory inspector (par. 139b of the G.O.), and the said medical man shall examine the workers once at least in every six months for symptoms indicative of plumbism.
The employer shall not permit any worker who is suffering from plumbism or who, in the opinion of the doctor, is suspected of plumbism, to be employed in any work in which he has to handle lead colours or mixtures thereof, until he has completely recovered.
Regulation 11.—The employer shall keep or shall cause to be kept a register in which shall be recorded the state of health of the workers, and also the constitution of and changes in the staff; and he shall be responsible for the entries being complete and accurate, except in so far as they are affected by the medical man.
Then follow the regulations as to entries in the Register, as to which see the Regulations as to lead smelting works, p. [300].
Type Founding and Compositors’ Work
(See also pp. [138] and [139])
Fumes which may carry up lead dust are generated in the casting of letters. Dust arises also in setting the type. General hygienic measures are especially called for such as healthy conditions in the workrooms. Much can be done by exhaust ventilation locally applied to the type cases and to letter (mono- and linotype) casting machines. Vacuum cleaning of printing workshops and type cases is strongly advised.
As some lead poisoning in printing works is attributable to lead colours or bronze powder containing lead their use should be limited as much as possible.
The German Imperial Regulations for printing works and type foundries are as follows:
Order of the Federal Council of July 31st, 1897, regulating Letterpress Printing Works and Type Foundries, in pursuance of Section 120e of the Industrial Code
I. In rooms in which persons are employed in setting up type or manufacture of type or stereotype plates the following provisions apply:
1. The floor of workrooms shall not be more than a half a meter (1·64 feet) below the ground. Exceptions may only be granted by the higher administrative authority where hygienic conditions are secured by a dry area, and ample means of lighting and ventilating the rooms.
Attics may only be used as workrooms if the roof is provided with a lathe and plaster ceiling.
2. In workrooms in which the manufacture of type or stereotype plates is carried on, the number of persons shall not exceed such as would allow at least fifteen cubic meters of air space (529·5 cubic feet) to each. In the rooms in which persons are employed only in other processes, there shall be at least twelve cubic meters of air space (423·5 cubic feet) to each person.
In cases of exceptional temporary pressure the higher administrative authority may, on the application of the employer, permit a larger number in the workrooms, for at the most 30 days in the year, but not more than will allow ten cubic meters of air space (353 cubic feet) for each person.
3. The rooms shall be at least 2·60 meters (8· feet) in height where a minimum of fifteen cubic meters are allowed for each person, in other cases at least 3 meters (9·84 feet) in height.
The rooms shall be provided with windows which are sufficient in number and size to let in ample light for every part of the work. The windows shall be so constructed that they will open and admit of complete renewal of air in workrooms. Workrooms with sloping roof shall have an average height equal to the measurements given in the first paragraph of this section.
4. The rooms shall be laid with close fitting impervious floor, which can be cleared of dust by moist methods. Wooden floors shall be smoothly planed, and boards fitted to prevent penetration of moisture. All walls and ceilings shall, if they are not of a smooth washable surface or painted in oil, be limewashed once at least a year. If the walls and ceilings are of a smooth washable surface or painted in oil, they shall be washed at least once a year, and the oil paint must, if varnished, be renewed once in ten years, and if not varnished once in five years.
The compositors’ shelves and stands for type boxes shall be either closely ranged round the room on the floor, so that no dust can collect underneath, or be fitted with legs, so that the floor can be easily cleaned of dust underneath.
5. The workrooms shall be cleared and thoroughly aired once at least a day, and during the working hours means shall be taken to secure constant ventilation.
6. The melting vessel for type or stereotype metal shall be covered with a hood connected to an exhaust ventilator or chimney with sufficient draught to draw the fumes to the outer air.
Type founding and melting may only be carried on in rooms separate from other processes.
7. The rooms and fittings, particularly the walls, cornices, and stands for type, shall be thoroughly cleansed twice a year at least. The floors shall be washed or rubbed over with a damp cloth, so as to remove dust once a day at least.
8. The type boxes shall be cleansed before they are put in use, and again as often as necessary, but not less than twice at least in the year.
The boxes may only be dusted out with a bellows in the open air, and this work may not be done by young persons.
9. In every workroom spittoons filled with water and one at least for every five persons shall be provided. Workers are forbidden to spit upon the floor.
10. Sufficient washing appliances, with soap and at least one towel a week for each worker, shall be provided as near as possible to the work for compositors, cutters, and polishers.
One wash-hand basin shall be provided for every five workers, fitted with an ample supply of water.
The employer shall make strict provision for the use of the washing appliances by workers before every meal and before leaving the works.
11. Clothes put off during working hours shall either be kept outside the workroom or hung up in cupboards with closely fitting doors or curtains, which are so shut or drawn as to prevent penetration of dust.
12. Artificial means of lighting which tend to raise the temperature of the rooms shall be so arranged or such counteracting measures taken that the heat of the workrooms shall not be unduly raised.
13. The employer shall draw up rules binding on the workers which will ensure the full observance of the provisions in sections 8, 9, 10, and 11.
II. A notice shall be affixed and a copy sent to the local police authority shewing:
(a) The length, height, and breadth of the rooms.
(b) The air space in cubic measure.
(c) The number of workers permitted in each room.
A copy of Rules 1 to 13 must be affixed where it can be easily read by all persons affected.
III. Provides for the method of permitting the exceptions named above in sections 2 and 3, and makes it a condition of reduction in cubic air space for each person employed as type founder or compositor that there shall be adequate mechanical ventilation for regulating temperature and carrying off products of combustion from workrooms.
Ceramic Industry
(See also pp. [135-8].)
A complete substitute for lead in glazes seems as yet impossible on technical grounds, as glaze containing lead has qualities which cannot be obtained without its use. In small works the technique necessary for the production of leadless glazes (special kinds of stoves) cannot be expected, especially as those carrying on a small industry lack the necessary knowledge of how to be able to dispense with the use of lead glazes and substitute leadless materials without complete alteration in their methods of manufacture. And yet discontinuance or the utmost possible limitation of the use of lead glazes and colours is most urgently needed in all small ceramic workshops, as they are not in a position to put in localised exhaust ventilation, &c., which is possible in large factories. Observance of even the simplest hygienic measures can scarcely be obtained. Consequently very severe cases of lead poisoning are met with in small works. An effort in the direction of discontinuance of lead glazes was made in Bohemia, where (at the cost of the State) technical instruction was given by an expert on the preparation of leadless glazes especially in districts where the industry was carried on in the homes of the workers. This procedure, extension of which is expected, had good results.
Many have demanded, in view of the possibility of substituting leadless for lead glazes, the total prohibition of lead. Such is the view of the Dutch inspector De Vooys; Teleky and Chyzer share the view expressed so far as the small industry is concerned, since the practicability of the change has been demonstrated.
English authorities (Thorpe, Oliver) propose diminution of the lead in the glaze in such a way that on shaking with weak acid not more than a specified small quantity shall be dissolved (Thorpe test). In my opinion such a measure is hardly enough for the small industry. I do not expect much good from obligatory use of fritted glazes.
In addition to earthenware, manufacture of tiles and bricks leads not infrequently to cases of lead poisoning from use of lead glaze.
The following measures apply to the larger ceramic works. Since risk is considerable, not only in glost placing but also in grinding, ware-cleaning, &c., closed ball mills in grinding and locally applied exhaust ventilation in ware-cleaning operations, &c., must be arranged. Personal cleanliness and proper equipment of a factory in all the essentials insisted on on pp. [226-9] are important, but nothing can take the place of efficient locally applied ventilation.
Vitreous enamelling of household utensils, baths, gas stoves, signs, &c., is an analogous process as enamels containing lead may be used. Sieving on the dry powder and brushing off superfluous glaze often cause poisoning. Here generally the same preventive measures apply.
[In Great Britain the china and earthenware industry is placed under Regulations dated January 2, 1913, which supersede the previous Special Rules. These Regulations—thirty-six in number—provide, among other usual provisions, (1) for efficient exhaust ventilation in (a) processes giving rise to injurious mineral dust (fettling and pressing of tiles, bedding, and flinting, brushing and scouring of biscuit) and (b) dusty lead processes (ware cleaning, aerographing, colour dusting, litho-transfer making, &c.); and (2) monthly periodical medical examination of workers in scheduled lead processes.]
In the Netherlands, in consequence of lead poisoning in porcelain works, committees were appointed to inquire into the subject in 1901, 1902, and 1903.
File Cutting
(See also p. [140])
In file cutting the file is cut on a lead bed or a bed of an alloy of zinc and lead. The same source of poisoning occurs in other industries such as amber working. Lead poisoning among file cutters is pronounced. The best preventive measure is substitution of a bed of pure zinc for lead. The German Imperial Health Office have issued a ‘Warning notice’ for file-cutters.
Leaflet for File-cutters
The use of lead beds or of alloys of lead with other metals has repeatedly brought about lead poisoning in file-cutters. The beds also supposed to be made of zinc usually contain a considerable proportion of lead, and are thus dangerous to health.
Among file-cutters lead poisoning arises from absorption of the metal in small quantities by means of dirty hands, eating, drinking, smoking or chewing of tobacco. The consequences of this absorption are not at once noticeable. They appear only after weeks, months, or even years, according to the extent to which the lead has accumulated in the system.
How does lead poisoning show itself?—The first sign is usually a bluish-grey line on the gums called the blue line, associated with anæmia or pallor. Later symptoms are very varied. Most frequently lead colic comes on, the affected person suffering from violent cramplike pains starting from the navel; the stomach is hard and contracted; very often vomiting and constipation ensue, or, very occasionally, diarrhœa. In some cases paralysis shows itself—generally in those muscles which extend the fingers, usually affecting both arms. In exceptional cases other muscles of the arms and legs are affected. Sometimes lead poisoning manifests itself in violent pains in the joints—generally the knee, more rarely in the shoulder and elbow. In specially severe cases brain trouble supervenes—violent headache, convulsions, unconsciousness or blindness. Finally lead poisoning may set up disease of the kidneys—Bright’s disease and gout.
Women suffering from lead poisoning frequently miscarry. Children born alive may, in consequence of lead poisoning, die in their first year. Children fed at the breast are poisoned through the milk.
Apart from severe cases complicated with brain trouble, which are often fatal, persons suffering from lead poisoning generally recover if they withdraw from further contact. Recovery takes place after a few weeks, but in severe cases only after months.
The most effective preventive measures are cleanliness and temperance. Persons who, without being drunkards, are accustomed to take spirits in quantity are more likely to succumb than the abstemious. Spirits should not be taken during working hours. In regard to cleanliness, file-cutters using lead beds should be especially careful and observe the following rules:
1. Since soiling the hands with lead cannot be entirely avoided, smoking and chewing tobacco during work should be given up.
2. Workers should only take food and drink or leave the works after thoroughly washing the hands with soap—if possible with pumice stone; if drinking during work cannot be wholly given up the edges of the drinking vessels ought not to be touched by the hands.
If a file-cutter falls ill in spite of precautions with symptoms pointing to lead poisoning he should, in his own and his family’s interest, at once consult a doctor, telling him that he has been working with a lead bed.
Other Industries in which Lead is used
In cutting precious stones with use of lead discs lead poisoning frequently occurs, especially where this trade, as in some parts of Bohemia, is carried on as a home industry. The authorities have required substitution of carborundum (silicon carbide) for lead discs. As, therefore, an efficient substitute is possible, use of lead should be prohibited. Similarly, use of lead in the making of musical instruments should, if possible, be discontinued. Brass pipes in musical instrument making are filled with lead to facilitate hammering and bending, and in this way poisoning has occurred. In numerous other industries where the use of lead cannot be avoided, and where consequently the danger must be present, as, for instance, in lead melting, soldering, lead rolling, stamping, pressing, &c., in the manufacture of lead piping, shot, wire, bottle capsules, foil, toys, and many other articles, general preventive measures should be carefully carried out. Melting of lead and lead alloys should be carried out only under efficient exhaust ventilation. In larger works where dust is generated this should be drawn away at the point where it is produced. This applies also to processes in the chemical industries where lead or lead compounds are used, seeing that no substitute is possible.
Zinc, Brass-casting, Metal Pickling, Galvanising
(See also pp. [151] and [182])
In zinc smelting account has to be taken of fumes which may contain lead, zinc, arsenic, sulphur dioxide, and carbonic oxide. Metallic fumes require to be condensed—a procedure in harmony with economic interests. This is effected in a technically arranged condensing system, consisting of a condenser and prolong, in which the fumes are given as large a space as possible in which to condense and cool. In order to prevent the entry of fumes into the shed when removing distillation residues, hoods should be arranged over the front of the furnace through which the gases can be conducted into the main chimney stack or be drawn away by a fan; in addition the residue should fall into trolleys which must either be covered at once or placed under a closely fitting hood until the fuming contents are cool. As the mixing of the materials for charging and the sifting and packing of the zinc dust (poussière) may cause risk, these processes require to be carried out mechanically with application of local exhaust. Such an arrangement is shown in [fig. 59] below. The material which is fed in is carried by the elevator to the sifting machine, falls into the collecting bin, and is then packed. The points at which dust can come off are connected with the exhaust and carried to the dust collector; fans carry the filtered air to the outside atmosphere.
Fig. 59.—Arrangement for Sieving and Packing Zinc Dust (poussière).
a Charging hopper; b Distributor; c Elevator; d Sieve; e Collector; f Packing machine; g Exhaust pipe; h Worm; i Dust Collector; k Motor
Only paragraphs 3-8 of the German Imperial Regulations dated February 6, 1900, for Spelter Works are quoted, as the remainder are on precisely similar lines to those for lead smelting works given in full on p. [300].
3. Crushing zinc ore shall not be done except in an apparatus so arranged as to prevent penetration of dust into the workroom.
4. The roasting furnaces as well as the calcining furnaces shall be provided with effective exhaust arrangements for the escaping gases. The occupier shall be responsible for their efficiency during the time the furnace is at work.
5. To avoid dust, ores intended for charging distillation furnaces shall not be stacked in front of or charged into the furnace, or mixed with other material, except in a damp condition.
This regulation shall not apply to large so-called Silesian
Retorts when in use in the zinc smelter; yet in the case of them also the Higher Authorities may require damping of the charging material if specially injurious to health.
6. Dust, gases and vapours escaping from distillation furnaces shall be caught as near as possible to the point of origin by efficient arrangements and carried out of the smelting rooms. The entrance of the gases from the fires into the smelting room shall be prevented as far as possible by suitable arrangements for drawing them off.
7. Residues shall not be drawn into the smelting room; they shall be caught in closed channels under the furnaces and emptied from these channels at once into waggons placed in passages beneath the distillation rooms.
This regulation (where the Higher Authorities approve) shall not apply to existing plants, should it be impossible to make the arrangements mentioned in Reg. 1, or where such additions could only be added by rebuilding at a prohibitive cost.
8. Sieving and packing of by-products obtained by the distillation of zinc (poussière, flue dust) shall not be done except in a special room separate from other workrooms, in accordance with Reg. 1.
Sieving shall only be done in an apparatus so arranged as to prevent escape of dust.
In brass casting, in order to prevent occurrence of brass-founders’ ague, it is necessary that the zinc oxide fumes evolved should be effectively drawn away from the crucible by locally applied exhaust ventilation. General ventilation merely of the room is almost useless, as in casting the fumes rise up into the face of the pourer. Seeing that casting is carried on in different parts of the foundry, it is advisable to connect up the hoods over the moulds by means of metal piping with the exhaust system, or to arrange a flexible duct which can be moved about as occasion requires.
Dangerous acid fumes (notably nitrous fumes) are evolved in metal pickling, especially of brass articles (such as harness furniture, lamp fittings, church utensils, &c.), for the purpose of giving them a shiny or dull surface by immersion in baths of nitric, hydrochloric, or sulphuric acid. As severe and even fatal poisoning has occurred in these operations they should be conducted in isolated compartments or channels under exhaust ventilation. If the ventilation provided is mechanical an acid proof earthenware fan or an injector is necessary. The following description applies to one large works: The pickling troughs are placed in a wooden compartment closed in except for a small opening in front. To this compartment a stoneware pipe leading to a stoneware fan is connected. The nitrous fumes are drawn through the pipe and led into the lower part of an absorption tower filled with cone-shaped packing material through which water trickles from a vessel placed at the top. The greater part of the acid fumes are absorbed as they pass upwards and the water collects in a receiver below, from which it is blown by compressed air into the vessel above for utilisation again until it becomes so charged with acid that it can be used for pickling purposes.
In galvanising and tinning acid fumes, injurious acroleic vapour, and metallic fumes can arise as the metal articles (iron, copper, &c.) first require to be cleaned in an acid bath and then dipped into molten fat or molten zinc or tin. Here also the fumes should be drawn away in the manner described.
Recovery and Use of Mercury
Escape of mercury vapour and development of sulphur dioxide seriously endanger workers engaged in smelting cinnabar. The danger can be minimised by proper construction of furnaces preventing escape as far as possible of fumes and most careful condensation of the mercury in impervious and sufficiently capacious chambers and flues.
Continuous furnaces are to be preferred to those working intermittently. The system of condensing chambers and flues must offer as long a passage as possible to the fumes, and care must be taken to keep them thoroughly cool. Removal of the deposit rich in mercury from the flues is especially fraught with danger. This work should only be carried on after efficient watering by workers equipped with respirators, working suits, &c.
Use of mercury.—Mirror making by coating the glass with mercury used to be one of the most dangerous occupations. Now that a fully adequate substitute for mercury has been found in the nitrate of silver and ammonia process, use of mercury should be prohibited. As a home industry especially mirror coating with mercury should be suppressed. Fortunately the dangerous mode of production is rapidly being ousted.
The following requirements are contained in a decree of the Prussian Government dated May 18, 1889:
(1) Medical certificate on admission to employment in mirror making with use of mercury;
(2) restriction of hours to six in summer and in winter to eight daily, with a two hours’ mid-day interval;
(3) fortnightly examination of the workers;
(4) air space per person of 40 cubic meters in the coating room and 30 in the drying room, and, in both, introduction of 60 cubic meters of air per head per hour;
(5) Work to cease if the temperature of the room in summer reaches 25° C.
Measures are necessary to prevent occurrence of mercury poisoning in hatters’ furriers’ processes (preparation of rabbit fur for felt hats) in consequence of the use of nitrate of mercury. Danger arises chiefly in cutting the hair, in dressing and drying, in sorting, and also in the subsequent stages of hard felt hat manufacture. Aspiration of the dust and fluff at its point of generation, isolation of the drying rooms and prohibition of entry into them while drying is going on, are necessary. In dressing (commonly known as ‘carotting’), the nitric acid vapour requires to be drawn away. In addition strict personal hygiene, especially of the teeth, is very important. Processes involving water gilding (nowadays practised on a very small scale) should only be carried on in stoves provided with exhaust ventilation. Electroplating, fortunately, has almost entirely taken its place.
As cases of mercury poisoning have been reported from use of mercurial pumps in producing the vacuum inside electric incandescent bulbs, air pumps should be substituted for them whenever possible.
Barometer and thermometer makers may and do suffer severely if care is not taken to draw away the fumes and ensure good ventilation of the workrooms. Careless handling and the dropping of mercury on the benches make it difficult to prevent some volatilisation. Personal hygiene and especially a proper hygiene of the mouth are of the greatest importance in this class of work.
Preparation of mercury compounds in chemical factories, especially the dry processes (sublimation), as in production of cinnabar, corrosive sublimate and calomel mixing, grinding, and sublimation, require to be carried on in closed apparatus. Preparation of the substances named above in solution involves much less risk than subliming. From our point of view, therefore, the former is to preferred.
Arsenic, Arsenic Compounds, Arseniuretted Hydrogen
For arsenic works imperviousness of the system and as complete condensation as possible are necessary to prevent escape of fumes.
Respirators should be worn in manipulations with white arsenic, and such work as packing done under conditions of locally applied exhaust ventilation.
Industrial use of arsenic compounds, in view of the risk attaching to them, should be reduced as much as possible. This has sometimes been achieved by technical improvement in processes of manufacture. Thus in the colour industry, where formerly colours containing arsenic played an important rôle, coal-tar colours have taken their place, and use of arsenic even in these (as in the manufacture of fuchsin) has been replaced by nitrobenzene.
As the danger from arseniuretted hydrogen gas is especially great in processes in which acid acts on metal and either one or both of them contain arsenic, the materials, should be as free from arsenic as possible, in the production, for example, of hydrogen for soldering, in extracting metals by means of acids, in galvanic elements, in accumulator works, in the storage and transport of acids in metal vessels, and in galvanising.
In any case the workers in these industries should be warned of the danger and instructed in case of emergencies. For soldering exclusive use of hydrogen produced electrolytically and procurable in steel cylinders is advisable.
Extraction and Use of Gold and Silver
In the extraction of gold and silver by amalgamation and subsequent volatilisation of mercury there is risk of mercurial poisoning. The preventive measures necessary are similar to those for poisoning in the recovery of mercury (see p. [327]).
Argyria in pearl bead blowers can be avoided by using pumps to blow the silver solution into the beads instead of the mouth.
In electroplating the possibility of poisonous fumes arising from the baths must be guarded against because hydrocyanic (prussic) acid, though only in minute quantities, may be evolved; care must be taken that the workrooms are well ventilated or the baths hooded. Careful personal hygiene is essential, for the prevention of skin diseases from which workers in electroplating often suffer.
VII
PREVENTIVE MEASURES IN OTHER TRADES
Ceramic Industry
In the glass industry use of lead, chrome, and arsenic compounds should be restricted as much as possible or allowed only under suitable precautions (exhaust ventilation, personal hygiene, &c.).
Etching on glass by means of hydrofluoric causes almost inevitably injury to the workers. Rendering the surface of glass opaque should preferably be done by sand blast. When a bath of hydrofluoric acid for etching on glass is used the fumes require to be drawn away by hoods over the baths and the work-rooms well ventilated.
Further precautionary measures are called for in view of industrial poisoning by furnace gases in various ceramic industries, as, for example, cement works, glass works, and tile works.
The following suggestions are made in the technical introduction to the Germany Factory Act for prevention of poisoning from carbonic oxide, carbon dioxide, and sulphur dioxide:
(1) Even the fixing of benches which might be used for sleeping on near the furnaces should be strictly forbidden;
(2) All furnaces which are roofed over should be provided with adequate side and roof ventilation;
(3) All gas pipes and cocks must be maintained in an impervious condition.
Manufacture and Use of Varnishes and Drying Oils
Unpleasant fumes are given off on boiling linseed oil with oxidising substances, which should be prevented by closely fitting covers and condensation of the fumes in cooling apparatus. In heating and dissolving resin for the production of varnishes the fumes evolved require to be dealt with in a similar way.
Preventive measures must be taken also in the use of quick-drying paints on ships and inside steam boilers as, owing to the rapid evaporation of the poisonous solvents—benzene, benzine and turpentine—fatalities have occurred. As a result of elaborate investigation by the inspectors of factories in Hamburg the following instructions were issued:
Quick-drying paint for ships and for preventing rust should only be used under the supervision of a person conversant with the danger to health and risk from fire.
They should only be allowed for the painting of interior surfaces after adoption of adequate precautions—free ventilation, use of smoke helmets with air conducting apparatus, and no naked lights, &c. Since use of quick-drying paints cannot easily be prohibited and the fumes from the substitutes for turpentine—benzene and other light tarry oils—exert injurious effect on man, precautionary measures are called for. Regulation of working hours is as important as provision of adequate ventilation. Workers, therefore, should be allowed proper intervals from work.
Confined spaces in the interior of ships should be adequately ventilated before, after, and during work; all persons who use the paints should have opportunity for washing given them at their work places, and should be compelled to avail themselves of these facilities; indulgence in alcohol and smoking should be prohibited; receptacles in which quick-drying paints are sold should be provided with an air-tight cover and with a warning notice as to the danger of the contents.
Paints made from petroleum fractions of low boiling-point, light coal-tar oils, turpentine oil, carbon bisulphide, and similar substances, are to be regarded as injurious to health.
Persons under eighteen, and women, should not be allowed to work with quick-drying paints.
Obligatory notification of cases of poisoning by hydrocarbons and other similar poisonings would have a good effect.
Schaefer (Inspector of Factories in Hamburg) has drawn up the following leaflet for painters, varnishers, workers in dry docks, and others engaged in painting with quick drying paints and oils:
All quick-drying paints and oils are more or less injurious to health and very inflammable, as they contain volatile substances such as benzine (naphtha, petrol ether), benzene, turpentine oil, carbon bisulphide, &c. These paints are mostly used in painting interiors of ships, boilers, machinery, apparatus, &c., and come on the market under various names, such as Black Varnish Oil, Solution, Patent Colour, Anti-corrosive, Dermatin, Acid-proof Paint, Apexior, Saxol, &c.
Even at ordinary temperatures the volatile fluids used as mediums for dry paint powders, or as a first coating, evaporate. Air filled with the fumes is not only harmful to health, but liable to explosion. Working with these paints and oils in the interior of ships, or steam boilers and the like, has repeatedly led to explosions and fatal poisoning.
Danger of Poisoning.—All persons are exposed to the danger of poisoning who use quick-drying paints in the interior of rooms or receptacles, or otherwise manipulate the paints. The warmer the room and the less ventilation there is before and during the painting, the greater the danger of poisoning. On the other hand, use of these paints in the open air is generally without effect.
Poisoning arises from inhaling the fumes of hydrocarbons. The symptoms are oppression, headache, inclination to vomit, cough, hiccough, giddiness, noises in the ears, drunken-like excitement, trembling and twitching. Inhalation of larger quantities brings on, quite suddenly and without previous warning, unconsciousness, which may last many hours and is often fatal. Except in severe cases the symptoms generally soon disappear, if the affected person withdraws from further contact with the fumes. The most effective protection therefore against poisoning is fresh air and temperance. In so far as painting with quick-drying materials is necessary in workrooms, interiors of ships, water and ballast tanks, double bottoms, bunkers, bilges, cabins, boilers and receptacles, care must be taken to ensure thorough ventilation before, after, and while the work is going on. Where no sufficient ventilation is possible these paints ought not to be used. Frequent intermission of work by a short stay in the open air is useful. When working in spaces not easily accessible, the worker should be roped.
Speaking, singing, or whistling during work favours inhalation of the fumes and is, therefore, to be avoided. Indulgence in spirits, especially during working hours, increases the danger of poisoning. Habitual drinkers should not be allowed to work at all with quick-drying paints and oils.
At the first signs of discomfort work should be stopped. An immediate stay in the open air will then usually dispel the poisonous symptoms.
If, notwithstanding this, severe symptoms develop, oxygen inhalation should be commenced forthwith and medical aid called in.
Production of Vegetable Foods and Luxuries
(See also p. [154])
Measures for the prevention of industrial poisoning have to be thought of in connection with drying processes (by smoke gases, carbon dioxide, and carbonic oxide), many processes of preserving (use of sulphur dioxide, &c.), and fermentation (accumulation of carbonic acid).
In breweries the use of kilns allowing fire gases to enter the drying-rooms formerly caused carbonic oxide and carbonic acid poisoning. The general introduction of hot air kilns provided with mechanical malt-turning apparatus should be insisted on, and is in keeping with progress in technical methods.
The accumulation of carbonic acid in the malting cellars can be prevented in the same way as in a distillery.
If ammonia is used for refrigeration, precautions are necessary so that, in the event of leakage or bursting of pipes, the workers may escape. Naturally the imperviousness of the freezing system must be guaranteed.
Oppression and danger to the health of the workers is occasionally caused by the development of gases in the coating of barrels with pitch, partly preventable by the use of pitching machines.
In the production of spirits carbonic acid poisoning can occur from accumulation of carbonic acid in the fermentation cellars. These should be thoroughly ventilated and in view of the heaviness of the gas, openings for ventilation should always be located at the floor level.
In the sulphuring of malt the following recommendations were made by the Austrian inspectors:
During the sulphuring process the room ought not to be entered (for the turning over of the malt). When the sulphur has been burnt, the drying-room must be ventilated from the outside, by opening the windows and letting in cold currents of air, until the sulphur dioxide has completely dispersed, which can be tested by holding a strip of moistened blue litmus paper at the half-opened door. If it does not turn red, turning over of the malt may be proceeded with.
As the sulphuring of hops in hop districts is done in primitive little kilns, in which the hops are spread out on a kind of gridiron and sulphur burnt below in iron pans, development of sulphur dioxide may affect the workers. The following regulations are therefore suggested for work in these kilns:
The rooms in which sulphuring takes place must be airtight, capable of being locked, and provided with arrangements which make it possible to remove the sulphur dioxide fumes before the room is entered. This can usually be done by a strong coke fire, maintained in the chimney place, which creates the necessary draught. If fans are used, it must be remembered that iron is affected and destroyed by acid gases; stoneware fans are therefore advisable.
In the production of vinegar, air escapes laden with acetic acid vapour, alcohol, lower oxidation products of alcohol, aldehyde, acetic ether, &c. Their escape can be avoided if the whole process is carried on in a closed self-acting apparatus with the advantage also that no loss occurs.
In premises for drying agricultural products (fruit, chicory, turnips) the persons employed in the drying-room are exposed to the danger of carbonic oxide poisoning from direct firing.
The following recommendations for work in drying-rooms with direct firing are taken from an Austrian decree of 1901:
The lower drying chambers, in which the real drying process is effected, should be so arranged that the objects dried in them can be removed by means of long-handled implements through a passage shut off from the drying-room. The separation of this passage can be effected by loose tin plates which can be removed as required for the work of turning or removal of the dried products, so that the worker need not come into contact with the gases.
Open fires should be so arranged that if required they can be shut off, by simple arrangements, from the drying-rooms in which the workers are temporarily occupied in carrying in, and turning, the objects to be dried, transferring the partly dried products to hotter hurdles, and emptying them when finished, in such a way that the entrance of combustion gases into the drying chambers can be completely prevented. In order, however, to prevent a back draught, arrangements must be made for simultaneous removal of the gases by pipes connected with a chimney or smoke flue. The places from which the fires are charged should, in addition, be furnished with suitably arranged openings for ventilation leading into the outer air, in order to neutralise, in case of need, any back draught from the furnaces into the rooms.
The windows of the drying chambers should be so arranged as to open both from within and without.
The floor of the roof space, or attic, which forms at the same time the ceiling of the upper drying-room, should be kept perfectly airtight, as also the openings into it through which the steam pipes pass. For this purpose the floor should be a double one and the openings or boxes into which material is thrown should have a double cover above and below. Further, situated in the highest point of the ceiling of the roof space, there should be a suitable number of openings topped by louvred turrets. In the roof space no work should be done except manipulations necessary for the charging of the hurdles with the goods to be dried. Use of the roof floor as a sleeping or living room is not permissible.
Before the workers enter the drying chambers for the purpose of turning the materials, the stove should be shut off, the gases drawn from the furnace into the chimney or flue, and at the same time the doors and windows of the drying rooms opened.
Entering of drying chambers for working purposes should only be done after a sufficient time has elapsed for removal of the air by ventilation.
Charging of the furnaces should be so arranged that they burn as low as possible before the removal of the dried materials and before subsequent work in the drying chambers. Seeing that chicory and turnip drying is done intermittently by night, a special sleeping or waiting room with free ventilation should be provided. The regulations concerning the ventilation of the workrooms are to be made known to the workers.
Cigar Industry
In order to prevent injury to health to tobacco workers the dust and fumes, especially at cutting and sifting machines, require to be drawn away by locally applied exhaust ventilation. The workrooms, moreover, must conform to hygienic requirements, especially as to cleanliness. Washing accommodation and baths are desirable, but are only likely to be provided in large works.
Wood Working
(See also p. [154])
Risk from poisonous woods can be avoided by exhaust ventilation applied to the wood-working machinery.
To lessen the danger to health in the use of methylated spirits in the polishing of wood adequate ventilation of the workrooms is necessary; drawing off the fumes by local ventilation is often impossible.
Production of Wood-pulp (Cellulose) and Paper.
In the sulphite cellulose process, sulphur dioxide may escape from the sulphur stoves or from the boilers; escape of sulphur dioxide is also possible through defective gas pipes and condensers. Gas pipes and condensers require to be quite impervious and condensation or absorption as complete as possible. The fumes escaping from the boilers should be led through pipes into closed boilers for condensation purposes; the gases not condensed here are to be led into absorption towers.
In the manufacture of paper with use of chloride of lime for bleaching chlorine can be given off in considerable quantity, requiring removal of the gases from the apparatus.
The use of poisonous colours containing lead or arsenic, and addition of lead-containing substances to the paper pulp, is now very rare.
Textile Industries.
(See also p. [156])
In the textile industry only a few manipulations are associated with serious risk of poisoning. Those engaged in carbonising are exposed to acid fumes; closed and ventilated apparatus, therefore, as far as possible, require to be used and the acid gases escaping from them should be absorbed. These requirements are fulfilled by carbonising stoves which are ventilated and connected with coke condensers. It is especially urged that only arsenic free acid be employed, as otherwise danger of poisoning by arseniuretted hydrogen may be incurred.
In the making of artificial silk, according to the Chardonnet-Cadoret process, the precautionary measures recommended in nitrating together with careful exhaustion of the ether and camphor fumes apply.
The combustion gases (containing carbonic oxide) developed in the process of singeing are harmful and require to be led away at their source.
Poisonous metallic salts, especially lead and lead-containing zinc, are used as weighting materials, in dressing or finishing, and sometimes cause symptoms among the workers. Apart from the danger to those occupied in spinning and weaving, the workers who handle these products (in the clothing trade) also run a risk from lead.
Precautionary measures are necessary in the varnishing of woven materials, as the substances employed may contain volatile poisonous solvents. If these poisonous solvents cannot be replaced by others less poisonous, carefully applied exhaust ventilation must be provided. The same holds good when carbon bisulphide, benzene, and benzine are used as solvents in the production of woven materials impregnated with indiarubber.
Employment of lead salts and other poisonous metallic salts in the glossing of woven materials, or in order to render them non-inflammable, is to be deprecated.
Cases of lead poisoning have occurred in the working-up of asbestos, as lead wire is sometimes used in the process of weaving.
To protect workers in chlorine and sulphur bleaching from poisoning by chlorine or sulphur dioxide the gases arising from the bleaching liquids should be drawn away. Use of closed bleaching apparatus, as is the case in large works, reduces the danger to a minimum. Bleaching-rooms should be connected with a powerful stoneware fan, so that they may be thoroughly aired before they are entered.
Dye Works
Industrial poisoning by dyes is, in general, rare, as the natural dyes (wood and tar dyes) are almost without exception non-poisonous. Further, the dyes are generally only used in diluted solution. Formerly the arsenic in many tar dyes caused poisoning, but now it is usually the mordants which have harmful effect. To this class belong chromic acid salts and mordants containing arsenic, antimony (tartar-emetic), and also chloride of tin. In the scraping off of layers of paint containing arsenic, arsenic dust may arise. In Turkey red dyeworks, especially sodium arsenite is used for fixing the tar dyes.
Orpiment dyes which may give off poisonous arseniuretted hydrogen gas are becoming less and less used; from the point of view of industrial hygiene, the utmost possible avoidance of the use of arsenic-containing preparations in dye works is to be recommended. Where this is not possible, strict personal hygiene must be enforced (as, for instance, application of vaseline to the skin).