In the manufacture of motor-cars, the terne (lead) coated sheets which form the body, after preliminary preparation, receive two coats of a lead paint. These are either lightly sandpapered or “flatted” with pumice and water. Three coats of non-poisonous filling follow, and are flatted with pumice or German brick and water. The body then passes to a skilled workman, who applies the final coats of colour. For facing mouldings and for corners throughout all stages of the processes, dry sandpaper takes the place of pumice and water. All stopping on the chassis, the first lead coat on the bonnet, and all coats of paint on the wheels, are sandpapered dry. Sometimes a third of a man’s time may be taken up in sandpapering alone.
Dangers and Prevention.
—Grave risk of inhaling lead dust is present (see the table on [p. 47]) when sandpaper is used, often at a point just above the mouth and nostrils. Rubbing down the wheels is perhaps the most dangerous work, and for this exhaust ventilation can be applied locally. Inventive genius has yet to be directed to some modification of the vacuum-cleaning apparatus, so that an exhaust can be attached to the back of the worker’s hand or in connection with a frame in which the sandpaper is held. In the process of wet rubbing, the abraded coats drip on to the floor, and when dry may rise as dust into the atmosphere.
Precisely similar operations, or only modified in detail, have accounted for heavy incidence of lead poisoning in the painting of perambulators, of safes, of bicycles, of bedsteads, of gas-meters, the “metallic” enamelling of baths (in which also chipping off of the old paint not infrequently occasions an attack), in engineering and machine-making works, in cabinet and furniture making, in French polishing, in the making of artists’ canvases, etc. Several cases are reported among railway employees engaged in the painting of bridges, girders, and signal-posts. A method for the removal of the dust given off in these processes has not yet been arranged. Chipping off of old paint can be effectually replaced by solvent solutions, in the use of which, as they are very inflammable, precautions against naked lights are necessary.
In the making of better-class measuring tapes, the tape, after passage through the white-lead mixture and drying, is made to travel through a machine to remove roughnesses, and subsequently through the fingers of the worker, protected by leather. Dust arises in both the last operations, and requires to be removed by exhaust ventilation. Similar means of prevention are necessary wherever paint is applied, as in photo-engraving, and colouring artificial flowers by means of an aerograph instrument.
Owing to the limited extent to which exhaust ventilation is possible, reliance must be placed on substitution of wet processes for dry wherever possible. Cleanliness of floors requires special attention. Although in all painting operations dust is the most potent cause of poisoning, we would assign to contamination of the hands and the eating of food with unwashed hands a more prominent place as a cause than in any of the other processes involving use of lead or lead colours. In a post-mortem on a sign-painter employed only a few days, made three weeks after his cessation of employment on account of an attack of encephalopathy, paint was found thickly adherent under the nails.
Substitution of colours containing no lead suggests itself as a simple remedy, but the progress in this direction made so far in the industries mentioned is limited. Several important firms manufacturing motor-cars use no lead colours at all; more than one important railway company (the outside of the carriages of which has no white colour) and a few makers of perambulators do the same. It is difficult to obtain knowledge how far leadless are replacing lead colours. In the manufacture of cornice poles (in which small industry several severe attacks were reported) the suggestion of a factory inspector to employ lithopone was adopted, with entire success. A patent graphite has been substituted for orange lead, with which wooden patterns to form the moulds of articles to be subsequently cast in metal are frequently painted.
House-Painting.
[35]—The work of house-painting and plumbing outside a workshop does not come under the Factory and Workshop Act, 1901, except to a limited extent under Section 105 in buildings in course of erection; and even in that case the requirement of notification of lead poisoning imposed by Section 73 does not apply. If, however, a house-painter is employed for part of his time in mixing paints in a workshop belonging to a builder, then the question may legitimately be raised as to whether plumbism may not have been due in some measure to such workshop conditions. Despite the limited extent to which the Act applies to lead poisoning of house-painters and plumbers, seeing that it is industrial in origin many practitioners notify cases, with the result that the number every year exceeds considerably that from any other lead industry in the country. Thus, the number notified in the ten years 1900-1909 was 1,973, including 383 deaths. The proportion of deaths to persons notified is much higher than for lead industries generally (19·4 per cent., as compared with 4·0 per cent.). If the proportion of cases to deaths were the same in house-painting as in other industries (and it is a fair assumption to make), the number of cases would be 9,418.
When investigation is made into the reported cases, the pre-dominance of the severer symptoms—paralysis, brain symptoms, and chronic plumbism—is brought out. Causation of poisoning, in order of importance, appears to be: (1) Dust from sandpapering one surface of paint before applying another; (2) dust from mixing dry white lead with oil; (3) dust arising from paint that has dried on overalls; (4) contamination of food with unwashed hands; and (5) fumes from burning off old paint.