Lead poisoning and lead absorption

by Sir Thomas Morison Legge; Kenneth Weldon Goadby

The dust removed from a composing box by a vacuum cleaner was found in the Government laboratory to contain 9·8 per cent. of metallic lead, and that collected from the top of the magazine of a linotype machine 8·18 per cent.

Regulations issued in 1911 in Austria require, among other things—(1) Melting-pots, and, so far as is practicable, linotype pots also, to be provided with hoods and ducts to carry the fumes to the outside air or into a chimney; (2) the type cases to fit either close on to the floor or with a sufficient space below the lowest drawer to enable the floor underneath to be easily cleaned; (3) the interior of all compositors’ boxes to be cleaned at least once every three months—if possible, by means of a vacuum suction apparatus; and (4) quarterly periodical medical examination to be made of persons employed in casting, stereotyping, linotyping, assorting type, and composing.

Sommerfeld[12] believes that in Berlin 1·07 per cent. of the compositors suffer from lead poisoning every year, and that 2·5 per cent. of all the diseases they suffer from are due to lead. Among 3,641 printers applying for sick relief, Silberstein[13] found 65 suffering from lead poisoning (1·7 per cent.). Where, however, diagnosis of lead poisoning is based upon examination of the blood, as in Leipzig, the amount of compensation paid by the Sickness Insurance Society has diminished considerably. Thus, of 207 compositors who were either sent by medical men as cases of, or went themselves suspecting that they were suffering from, lead poisoning, only 17 (8·2 per cent.) showed basophilia to such degree as to warrant the diagnosis. The proportion, on the other hand, among letter founders and electrotypers was 28·6 per cent.

Printers suffer extensively from phthisis, their comparative mortality from this cause as compared with the figure for all occupied males being 290 : 175[14]. This high mortality is probably due mainly to the vitiation of the atmosphere, and reluctance, on account of extreme sensitiveness to draughts, to admit fresh air. This closing of windows by persons employed should be an additional reason for checking the vitiation from Bunsen burners in connection with linotype and monotype machines by the only practicable means of preventing perceptible draught—namely, exhaust ventilation.

File-Cutting.

[15]—The steel file to be cut is placed on a stone block in the centre of which is inserted a smaller steel block, called a “stiddy.” The worker holds in his right hand a hammer, weighing sometimes 7 or 8 pounds, and in his left, closely gripped, a chisel. Each tooth in the file—and there may be as many as 3,800 teeth to be cut—is the result of a blow on the chisel, and we have counted as many as 120 blows with a 7-pound and 200 with a 4-pound hammer per minute. To offer resistance to the blow and yet prevent a recoil, the file (in the case of the finer kinds) is placed on a lead bed—that is, a thin strip of metallic lead. With attrition from repeated impact the lead bed becomes worn away in the course of a few days, and part of what is so worn away necessarily takes the form of lead in fine particulate state.

Dangers.

—Absorption of lead follows from the dust generated by each blow, from brushing the dust off the cut file, and from licking the finger and thumb holding the chisel. Other conditions predisposing to plumbism before the present regulations came into force, and not altogether without effect still, were—too close proximity of one stock to another, defective ventilation of the (frequently) small shed in which the work was done, overcrowding, accumulation of dust on the benches, uneven floors, inadequate washing facilities, and, apparently, lack of appreciation of the danger.

The remarkable feature of plumbism in this industry is the long duration of employment before pronounced symptoms manifest themselves (see [p. 51]). The insidious onset is, however, accompanied by an undermining of the constitution, showing itself eventually in atrophy of the muscles, especially of the thenar and hypothenar eminences of the hand, and of the lumbricals and interosseous muscles of the fingers, the result of continual gripping of the hammer and chisel, chronic interstitial nephritis, with its associated arterio-sclerotic changes, and heavy incidence of phthisis.

Provision of locally applied exhaust ventilation has never been suggested for this industry, owing to absence of power to drive a fan in the small workshops, and because no lead dust is seen to be given off. Diminution in the number of cases is due to the fact that machine file-cutting (with zinc as the bed) has been substituted for hand file-cutting for coarse files. In hand cutting, in some instances, beds of pewter, or of alloys with comparatively small proportion of lead, have replaced the use of lead beds. The remedial measures prescribed in the regulations have also played a part.