Lead poisoning and lead absorption

by Sir Thomas Morison Legge; Kenneth Weldon Goadby

REFERENCES.

[1] Annual Report of the Chief Inspector of Factories for 1910, p. 172.

[2] Ibid., pp. 172, 173.

[3] G. Elmhirst Duckering: A Report on an Experimental Investigation into the Conditions of Work in Tinning Workshops, and Appendices. Included in Special Report on Dangerous or Injurious Processes in the Coating of Metal with Lead or a Mixture of Lead and Tin. Cd. 3793. Wyman and Sons, Ltd. Price 1s.

G. Elmhirst Duckering: The Cause of Lead Poisoning in the Tinning of Metals. Journal of Hygiene, vol. viii., pp. 474-503, 1908.

G. Elmhirst Duckering: Report on an Investigation of the Air of Workplaces in Potteries. Included as Appendix XLIX. in Report of the Departmental Committee appointed to inquire into the Dangers attendant on the Use of Lead, and the Danger or Injury to Health arising from Dust and Other Causes in the Manufacture of Earthenware and China, vol. ii., pp. 93-113, 1910. Cd. 5278. Price 1s. 9d.

[4] G. Elmhirst Duckering: Annual Report of the Chief Inspector of Factories for 1910, p. 47.

[5] C. R. Pendock (one of H.M. Inspectors of Factories): Report on Systems of Ventilation in Use in Potteries. Included as Appendix XLVIII. in vol. ii. of Potteries Committee’s Report referred to under[3].

C. R. Pendock: Second Report of the Departmental Committee appointed to inquire into the Ventilation of Factories and Workshops, part i., and especially part ii., 1907. Cd. 3552 and 3553. Price together, 4s. 8d.

Other works referred to include—Construction des Usines au Point de Vue de l’Hygiène, by Ingénieur-Architecte Maniguet. Ch. Béranger, Paris, 1906; Hygiène Industrielle, by MM. Leclerc de Pulligny, Boulin, and others. J. B. Baillière et Fils, Paris, 1908; and many excellently illustrated trade catalogues issued by ventilating engineering firms, such as the Sturtevant Engineering Company, Ltd., London; Henry Simon, Ltd., Manchester; Davidson and Company, Ltd., Belfast; John Gibbs and Son, Liverpool.

CHAPTER XIII
PREVENTIVE MEASURES AGAINST LEAD POISONING—Continued

Periodical Examination.

—In various codes of regulations a surgeon is required to make periodical medical examination of the workers. The term “surgeon” is defined as the “Certifying Factory Surgeon of the district, or a duly qualified medical practitioner, appointed by written certificate of the Chief Inspector of Factories, which appointment shall be subject to such conditions as may be specified in that certificate.” The wording of the regulation varies somewhat in different codes, but the intention in all is the same, and the following example from the Tinning Regulations will indicate the purpose and scope:

“Every person employed in tinning shall be examined by the surgeon once in every three months (or at such shorter or longer intervals as may be prescribed in writing by the Chief Inspector of Factories), on a day of which due notice shall be given to all concerned. The surgeon shall have the power of suspension as regards all persons employed in tinning, and no such person after suspension shall be employed in tinning without written sanction from the surgeon entered in the health register.

“Every person employed in tinning shall present himself at the appointed time for examination by the surgeon. No person employed in tinning shall, after suspension, work at tinning without written sanction from the surgeon entered in the health register.”

Under the Special Rules for white-lead works, examination is required at weekly intervals; under the Special Rules for Earthenware and China, Manufacture of Litho-Transfers and Red Lead, and under the Regulations for Electric Accumulators, and Paints and Colours, monthly; under the Regulations for Tinning, Yarn dyed with Chromate of Lead, and Enamelling, at quarterly intervals, subject to the limitation or extension specified in the regulation quoted.

The limitation as to quarterly examination is useful to meet conditions, on the one hand, where special incidence calls for increased safeguards; and, on the other, relaxation, by reason of adoption of special processes or measures lessening risk. Thus, in a yarn-dyeing factory, in consequence of occurrence of six cases within five months, a weekly instead of a quarterly examination was prescribed. After eight months, as no further cases were reported, a monthly examination was substituted for the weekly, and eventually, with continued absence of illness, the normal quarterly examination was resumed.

An appointed time for the surgeon’s attendance at the factory has been found necessary, because, in conformity with the literal wording of the regulation, the occupier should not continue to employ a worker who, for one reason or another, has not been examined by the surgeon during the prescribed interval. With knowledge of the date and hour posted in a conspicuous place in the factory, excuse for absence becomes difficult. Alteration by the surgeon of his appointed time should, whenever possible, be given beforehand. Surgeons in the past frequently made examination of the persons employed with the view of taking them unawares, and so of precluding special preparation beforehand—a practice which had its advantages; but they are outweighed by the hardship inflicted on workers who were unavoidably absent, as, for example, night-workers. A health register is supplied to all occupiers where periodical medical examination is enjoined, the headings of which and manner of entry are indicated later on in this chapter.

The objects which the surgeon should have in mind in making his examination are:

1. To prevent lead poisoning and minimize lead absorption.

2. To obtain information for the occupier and Inspector of Factories of the relative danger of one process and another with a view to adoption of remedial measures.

In safeguarding the health of the workers, he should make effort to gain their confidence, in order to be able to attach proper value to statement as to subjective symptoms. Suspicion in their minds that the examination is made solely in the interests of the employer militates against success, and increases inclination to conceal symptoms and to give untruthful answers as to the state of health since the last examination. In our opinion, the surgeon will best carry out the first object by attention to the second. The study of thousands of reports on cases of lead poisoning convinces us that 90 per cent. at least are due to inhalation of dust and fumes. The surgeon, therefore, should utilize the earliest sign of lead absorption to warn the occupier and inspector of conditions favourable to the development of plumbism, and due probably either to some unguarded spot in the manufacturing process whereby dust or fumes are not being removed completely, or to ignorance or carelessness (often excusable in the absence of proper instruction) on the part of the worker. He should direct, therefore, especial attention to new workers, not only because of their need for guidance as to precautions to be observed and greater liability to attack during the first year of employment, but also because development of signs in them constitutes the surest guide to defects in the process of manufacture. Occasionally symptoms in a worker may be so menacing as to demand immediate suspension, but generally before the power is exercised attempt to rectify the condition which gives rise to them should be made. The surgeon can do much by influencing the foremen and forewomen, who will necessarily come before him for examination, in insisting on the supervision by them of care and cleanliness by the workpeople under their charge. Should suspension, despite attention in the manner suggested, be necessary, he will recognize that transference to a non-lead process, if feasible, is preferable to entire cessation from work in very many cases. The surgeon, therefore, should know what departments are possible alternatives to lead work.

The fact that an examination is made on factory premises, is directed to detection and prevention, treatment taking a subordinate place, and is often made on persons who, unlike hospital patients, seek to conceal their symptoms, causes it to be an examination sui generis. Hence the surgeon must trust his sight more than his hearing. A surgeon with experience of such work has said: “The worker in lead must be surveyed as an individual, and idiosyncrasies must be carefully studied and allowed for; the ‘personal equation’ is of vital importance”[1].

For the examination a well-lighted room affording privacy is essential. While it is desirable for the surgeon periodically to see the processes and conditions under which work is carried on, systematic examinations of workers should not be made elsewhere than in a private room. The custom of marshalling workers in a queue, although perhaps unavoidable in many cases, is liable to detract from the seriousness of the proceedings, a sense of which it should be one of the aims of the examination to arouse. In discussing the method of interrogation and usual examination, Dr. King Alcock[2], Certifying Factory Surgeon of Burslem, says: “Note the general manner assumed in answering questions and any indications of carelessness in dress and toilet. Inquire into the state of digestion, existence of colicky pains, regularity of bowels, menses, history of pregnancies and miscarriages, whether before, in the intervals of, or during lead employment; existence of headache, diplopia, or amaurosis. Note the type, facies, state of teeth and nails, complexion, speech, tongue, strength of grasp (if possible, with dynamometer), any tremor in outstretched hand, resistance to forcible flexion of wrist.... If strabismus is present, note whether of old standing or recent; and if ocular troubles seem imminent, examine for optic neuritis, either at once or at home (this is very important, as cases of acute and serious optic neuritis still baffle examination by their intermensual development).” He recommends the surgeon, apart from entry in the health register, which must necessarily be very brief, to keep a private notebook, and to enter in it as a matter of routine such details as name, process, age, duration of employment, condition (married or single), pregnancies, state of bowels and menses, dental toilet, and any special point worthy of note in individual workers. A card index, if in use, might conveniently serve for such entries.

In the actual routine examination it may be useful to describe the procedure where a large number of workers pass before the surgeon in a white-lead works every week. The points noted are:

1. The general appearance of the man as he walks forward, especially the face with regard to anæmia, which in the majority of cases of early lead absorption is not a true anæmia, but is due to vaso-motor spasm of the arterioles of the face and eyes. Frequently, on speaking to a lead-worker, the face, apparently anæmic, flushes directly.

2. The brightness of the eyes, state of the pupils, and condition of the conjunctiva and of the ocular muscles.

3. The mouth should next be examined, and search made for any evidence of blue line around the gum.

4. The gait should be watched both on advancing to, and retiring from, the surgeon. If necessary, the man should be made to walk a few steps. Although the peroneal type of palsy is extremely rare, the possibility of its occurrence should never be absent from the mind of the surgeon.

5. The man should then be directed to stretch his hands out in front of him, with wrists extended and fingers widely spread. Presence or absence of tremor should be looked for, and the condition of the finger-nails, as to the practice of biting, etc. The extensor power should then be tested, firstly of the fingers. While the hands of the workman remain outstretched, the surgeon places the forefinger of his hand in the outstretched palm of the workman, and the ball of the thumb upon the extreme tip of each finger, and by gently pulling it down, noting the spring present in the muscles. This test is probably the most delicate there is for detection of early extensor paralysis. The condition of the lumbricals and interossei are noted on movement of the fingers. The extensors of the wrist are then further examined, the workman being directed to flex his arm at the elbow and strongly pronate the wrist, so that the palm of the hand is directed forwards. He is then told to close the fist when the surgeon endeavours to flex the wrist, the workman at the same time resisting by forcible extension of his wrist. Ordinarily the extensor communis digitorum and minimi digiti are sufficiently powerful to resist a very powerful pull upon the wrist; and if the wrist is found to yield, it is a sign that the muscles are affected. Sometimes the strength of the wrists and fingers is judged by the surgeon placing his palms on the dorsum of the patient’s outstretched hands, and seeing whether the patient can be prevented from lifting them without flexing the wrists or finger-joints.

The test detects (1) paralysis which has been recovered from to a large extent; (2) commencing partial paralysis; and (3) weakness of muscular power, especially in those who have worked in lead for a number of years. This weakness appears to be an effect of lead upon the muscular tissue or dependent on debility, the result of lead absorption, and independent of nerve implication. We have known the condition to remain unaltered for years, and also to undergo alteration, being at times absent for months together. Occasionally reports of definite paralysis refer to pre-existing weakness.

6. The pulse is next noted. The pulse-rate need not ordinarily be counted, but if it is either very slow or fast careful examination at the conclusion of the general inspection should be made.

It is well to make all these points before asking any questions. After they are completed inquiry as to regularity of the bowels, existence of pain or discomfort, would follow. The speech should be noted, as slurring or hesitating speech is occasionally associated with early lead poisoning.

All these points can be gone through quite rapidly, and at the conclusion of the general examination, if judgment is in suspension, careful examination in the routine medical manner should be made.

In some factories all new workers are examined by the surgeon before they commence work in dangerous processes. At any rate, a list of such persons should be given to the surgeon at his visit, as naturally the question of personal fitness for employment should be decided at his first examination. Conditions which should lead to rejection are tubercular disease of every kind, idiopathic epilepsy, all forms of mental disease or weakness (hysteria, feeble-mindedness, and neurasthenia), obvious alcoholism, women who are pregnant or who give a history of repeated miscarriages prior to work in lead, persons with marked errors of refraction unless corrected by glasses, kidney disease of all kinds, evidence of previous chronic saturnism, and bad oral sepsis. Special attention will have to be paid to casual labourers, and it should be the aim of the surgeon to discourage this class of labour in lead industries. Work under special rules or regulations requires to be carried out under strict discipline, and this it is extremely difficult to maintain on other than regular workers, who recognize the need for cleanliness and observance of regulations.

Other aids to diagnosis cannot be carried out as a matter of routine, but will necessarily be used in particular cases, such as ophthalmoscopic examination of the fundus, electrical reactions of muscles, analysis of the urine, and examination of the blood-pressure.

A few words may be added on the significance of the two commonest signs—the blue line and anæmia. It cannot be too strongly insisted on that presence of the Burtonian line on the gums is, as a rule, indicative of lead absorption, and not of lead poisoning. As a danger signal its value is immense, and hardly less so its value in clinching diagnosis in doubtful cases. Whenever the line is seen risk is imminent, and poisoning (not necessarily of the individual in whom it is pronounced) among the workers is inevitable in the absence of adoption of precautions. Unfortunately, careful dental toilet, which the surgeon will necessarily lay stress on, may prevent development, or the practice, when adopted, cause disappearance of the line after the lapse of a few months. Under these circumstances, the merest trace will have all the significance of the fully-developed line in a worker neglectful of care of the teeth. Among new workers a commencing blue line should be strong evidence of the need for dust removal at some point in the process of manufacture. The line, in our experience, is dense in occupations giving rise to fumes or to dust of compounds of lead, but comparatively rare in those handling metallic lead or its alloys, as compositors, tea-lead rollers, solderers, and the like.

Some degree of pallor is so commonly met with in adolescence that it is the progressive development of the anæmia which the surgeon must especially watch for. As a danger signal, therefore, it has the same significance nearly as the blue line; but when lead absorption has affected the elements in the blood, progressive anæmia in new workers, attributable to the employment, and showing no tendency to improve after watching for a few months, is an indication for suspension or transference to other work. In older workers, with a duration of employment of five years or more, there may be a quasi-pathognomonic pallor which does not vary from year to year. In them it must be supposed that an equilibrium has been established, and development of other symptoms, such as tremor, wrist weakness, or albuminuria, becomes significant. Attention has already been directed to the distinct saturnine facies associated with anæmia, and characterized by loss of fat, particularly noticeable in the orbit and buccinator region of the face. “So far as the question of any worker’s suspension is concerned,” says Dr. King Alcock, “I prefer to make my instinctive primâ facie distrust of a saturnine pallor the basis for action. The pallor of plumbism cannot be summed up in hæmoglobin and corpuscular content; it is the expression of a complex toxæmia resulting from defective assimilation and excretion”[3].

The knowledge the surgeon should gain of the idiosyncrasies of the workers by his periodical examination will enable him to appraise at their proper value the nature and degree of the symptoms in notified cases.

Sometimes a rule is made that no lead-worker who has suffered from an attack of plumbism should be allowed to resume work. This we consider too harsh a measure. It may be true for painters, but when remedial measures, such as locally applied exhaust ventilation, can be applied, with consequent removal of the danger in the process at which the poisoning has arisen, prohibition of employment seems an unnecessarily drastic measure.

The health register in general use where periodic medical examination is required in pursuance of special rules and regulations is divided into two parts, in each of which entries by the surgeon are required at each visit.

Part I.
List of Persons Employed in Processes.						Particulars of Examination.
No.	Worker’s Name, in full.		Process.	First Employed in such Process.		Date Result.	Date Result.	Date Result.	Date Result.
				Age.	Date.
(1)	(2)		(3)	(4)	(5)	(6)	(7)	(8)	(9)
Part II.
Reference to Part 1.		Date of Examina- tion.	Number of Persons Examined.	Particulars of any Directions given by the Surgeon. Any Certificate ofSuspension or Certificate permitting Resumption of Work must be entered here in full.				Signature of Surgeon.
Page.	Col.
(1)	(2)	(3)	(4)	(5)				(6)

In [Part I.] of the register the surgeon should, at the times of examination, enter the date at the head of one of the columns numbered 6 to 9; and in the space below, opposite the name of each person examined on that date, a brief note (see [next page]) of the condition found.

In [Part II.] he should again enter, in Column 3, the date of examination, with a statement of the total numbers examined on that occasion (Column 4); and in Column 5 any certificate of suspension from work, or certificate permitting resumption of work, and particulars of any other direction given by him, appending his signature in Column 6.

It is the duty of the occupier to enter in [Part I.] the following particulars with regard to each person examined: (1) Name in full (Column 2); (2) the process in which he or she is employed (Column 3); (3) age when first employed (Column 4); and (4) date of first employment in that process (Column 5); and these particulars, in respect of each person so employed, must be entered immediately on commencement of work in the process named.

Various methods of noting the state of health of the workers have been adopted. Use of the words “Good,” “Very fair,” and “Fair,” is common as indicating the state of general health, with special note in addition, often in the form of a symbol, of the presence and character of definite ill-effects. The object of the register, however, is to keep a record intelligible not only to the Certifying Surgeon, Factory Inspector, and occupier, but also to the workers. Entries, therefore, on a uniform system are desirable, taking account of the two aspects of the health of every lead-worker, which must be considered (a) that indicative of specific effects from the occupation, and (b) that of general health uninfluenced by the employment. With this in mind, the following system of entry in the health register has been adopted:

The entries should be made upon a uniform system, as below, indicating degrees of deviation from normal health, and distinguishing (by use of numerals) those attributable (or possibly attributable, in whole or part) to work in lead, from those not so attributable, for which latter letters should be used. The conclusion is perhaps best expressed as a fraction 1 A, 2 C, and so on.

The numerals should be taken to mean:

1. Passed without comment (no observed effect of lead).

2. Blue line (or indication thereof).

3. Marked (quasi-pathognomonic) anæmia, or other signs of impairment of health. (Albuminuria, or slight deficiency in tone of the extensor muscles of the forearm, would, and miscarriage, or other suspicious history of illness between examinations, might, come under this head.)

4. Suspension or transfer, by reason of impairment of health from effects of work in lead. (In such cases the surgeon would be prepared to entertain an application for a certificate under the Workmen’s Compensation Act.)

Except in the case of a worker whose exposure to lead is only recent, renal disease should always be indicated by a numeral.

Letters should bear the following meaning:

A. No comment (i.e., fair general health).

B., C. Increasing degrees of impairment of general health. (Pregnancy, if without suspension, should be entered as C.)

D. Suspension or transfer, for reasons other than impairment of health from effects of work in lead.

X. Carelessness, or neglect of precautions, or unsuitability for work in lead. (Suspensions for such reasons should be marked DX.)

Such entries of numerals and letters will in general suffice for the intended purpose; but the surgeon may, of course, find it desirable to make other notes for his own information, and it is within his discretion to supply further details to occupiers or workers concerned.