(8) Metal ducts, 9¹⁄₂ inches in diameter. Evidence of ill-health was greatest here, notwithstanding good draught, because the branch ducts were not brought close enough to the point where “heading” was done, but were distant 15 inches from the centre of the post, and “noddling” was done at a distance of 2 feet from the duct, one man standing between the draught and the bar.
(10) Draught arranged as in (7), below the bar, without protection of the worker by a glass screen.
Regulations now apply to the industry. So clear is it that locally-applied exhaust ventilation is of paramount importance in prevention of poisoning, that, however intermittent the operation of “heading,” exemption from this requirement cannot be permitted. Determination periodically by the occupier of the speed of the draught at each exhaust opening should prevent blockage of ducts.
The regulations do not apply to the winding of, and weaving with, yarn dyed with chromate of lead. Rarely in the spinning and weaving factories of Blackburn does the amount of the particular yarn in question constitute as much as 5 per cent. of the total quantity of coloured yarn used. Section 74, 1901, is sufficient to meet the isolated cases where injury to health arises. The habit of biting chrome-dyed thread has given rise to lead poisoning. Nor do the regulations apply to treatment of calico or cloth into which lead may enter. Such poisoning as may occur must be practically confined to persons employed in the paint-mixing house.
Manufacture of India-rubber.
[9]—Litharge, massicot, red lead, and sulphide of lead, are generally mixed with rubber. Litharge is regarded not only as a valuable filler for rubber, but has the faculty of hastening vulcanization. All dry-heat goods depend upon it where a dark or black effect is wanted.
Every year a few cases are reported in the process of mixing the batches in the weighing room of the rubber factory, or more frequently at the hot calender rolls, where the batch of dry powder containing the lead compound is gradually distributed by hand on to the rubber so as to effect an intimate mixture. The heated air over the rollers causes dust to rise. According to the purpose for which the rubber is wanted, the quantity of litharge in the batch varies. In one factory of fourteen men employed at the calender rolls, ten showed a blue line, five were markedly anæmic, one had weakness of the wrists, and two weakness of grasp[40]. Only one case has been reported since exhaust ventilation was applied locally over each calender roll. In a rubber tyre factory five cases followed one another in quick succession, all in persons employed on the rolls. There should be no hesitation in requiring exhaust ventilation wherever employment in mixing the batches or at the rolls is constant. In general, however, the work in weighing out is intermittent, and reliance is placed on the wearing of a respirator.
No attempt has been made to enumerate all the industries and processes in which lead poisoning may arise. The task would become wearisome, as they are so numerous. Nor is it necessary to give details of all that are known, as it is doubtful whether there can be any different in nature or requiring different treatment from the many which have been described.
REFERENCES.
[ [1] Special Report on Dangerous or Injurious Processes in the Smelting of Materials containing Lead, and in the Manufacture of Red and Orange Litharge and Flaked Litharge, by E. L. Collis, M.B. Cd. 5152. 1910. Wyman and Sons, Ltd. Price 6d.