In assembling or putting together of the formed plates, and in earlier stages of the manufacture also, filing or use of a wire brush causes production of metallic lead dust and of the oxides when the brush touches them—a danger only to be met by exhaust ventilation. How far the poisoning to which the lead burners engaged in assembling plates is attributable to lead fume, produced by the high temperature of the blowpipe flame, and how far to handling (with inevitable dislodgment of dust) has not been satisfactorily settled. Incidence of poisoning on this class of worker in the past has been marked.
Generally there is need for impervious floors, solidly built, so as to prevent vibration and the raising of dust from passage of trolleys conveying the heavy plates. Gloves are frequently provided, more to protect the hands from contact with the sulphuric acid used in making the paste and jagged edges of the plates than as a preventive of lead absorption.
In the 10 years 1900-1909 incidence, according to precise occupation, has been—Casting, 33; pasting, 114; lead burning, 69; and assembling the plates, etc., 69.
Glass-Cutting.
[31]—Red lead enters largely into the mixture of raw materials for the manufacture of glass. Flint glass, for instance, contains 43 per cent. of lead. The raw materials (white sand, red lead, and generally saltpetre) require to be very carefully mixed, and a few cases of poisoning have been reported from the dust raised in sieving. One man works the sieve, resting on two runners across the bin, while another shovels the mixture into the sieve. The operation is not a continuous one, and respirators have principally been relied on to protect the workers. It should be possible to carry out the mixing operations in a dust-tight closed apparatus.
Poisoning from lead fumes generated in a glass furnace is unknown. Lead poisoning used to be common in the process of polishing cut glass on a brush by means of “putty powder” (oxide of tin, 29 per cent.; and oxide of lead, 71 per cent.), mixed with water to the consistency of a paste. The brush was made to revolve at high speed, with dissemination of the putty powder as a fine spray into the atmosphere of the workroom. Although rouge and oxide of iron have replaced putty powder to some extent—especially for the polishing of the bevelled edges of plate glass—no substitute can at present be found to give the final lustre and brilliancy required in the case of cut glass and in certain kinds of high-class work, such as polishing lenses.
Locally applied exhaust ventilation has robbed the process of its dangers. Pyramidal-shaped hoods enclose the spindle and putty box and brush before which the workman sits. The draught of the fan prevents escape of spray. The lad who feeds the brush with putty powder stands at the side, and in our experience his cap and clothes are now free from signs of splashing. Formerly the polishing was done by each man at his own berth, thus endangering the health of all working in the vicinity, as the custom of the trade is that the same man carries through the work both of cutting and polishing. Polishing occupies only about a fifth of a man’s time, and it has now, owing to the position of the fan, to be carried out in one particular part of the room.
Dr. D’Arcy Ellis[32], Certifying Surgeon for the Stourbridge district, has described the processes as formerly carried out:
“The mixture of lead and tin is heated over a bright fire in a shallow iron pan. As it melts, the top scum which forms is skimmed off, dried, pounded to a powder in an iron mortar, and afterwards sieved. The person who does this work always suffers more or less. He usually protects himself by wearing a respirator—there is a good draught at the flue, and the sieve is enclosed in a box—but there is always a certain amount of dust. This putty-powder is used on the wooden wheel, and is dabbed on the wheel as it revolves. All good bold work can be polished in this way, and there is not much risk to the workman, as the speed at which the wheel revolves causes the mixture to cling and not fly about. This process does not answer for any fine work, so it is contended; and to enable this kind of work to be properly polished brushes made of bristles are used. They are mounted on an iron spindle, and are usually about 6 inches to 7 inches in diameter, with a face of 1 inch to 1¹⁄₂ inches broad. They are driven at a speed of about 2,000 revolutions a minute. The putty powder is applied to these brushes (which are of various sizes) in the same way as to the wooden wheel—that is, by dabbing it on. For smaller work, such as tumblers and wine-glasses, the workman applies the putty mixture himself, holding the glass against the brush with his right hand, and using his left underneath to apply the mixture. Where, however, larger work has to be done in which the workman cannot manage with one hand, the service of a boy is called in, who does what is called the ‘feeding up.’ This boy stands partly in front and partly at the side of the brush, and applies the mixture with one hand with the wisp of straw. In this position the boy gets splashed with the putty mixture which flies off the brush, and it is generally believed by the workmen to be the most dangerous occupation. At one time—not very long ago—all the various processes of the work were done indiscriminately in the workshop, and consequently the men were frequently found working in a perfect haze of fine dust, which had been thrown off from the brushes. There was no attempt made to separate and detach the less injurious part of the work, such as the roughing and cutting, from the general workshop, the lead polishing only occupying about one-fifth of the workmen’s time. After the glass has been polished by the putty it is taken away to another department, where girls are employed as ‛wipers out.’ They take the glass with the dried putty upon it, dip it into a basin of water, and then wipe it dry. Some of these girls have been known to suffer from lead poisoning.... Drop-wrist was frequently to be seen—in fact, there was hardly a workshop in the district in which cases of wrist-drop could not be found. They were all anæmic, and the albuminuric and prematurely aged were frequently met with.”
In this small industry in the past the poisoning must have been considerable. In 1898 nineteen cases were reported. Reference to the table on [p. 47] shows that the number now is greatly reduced. Those reported are generally cases which have ended fatally from the sequelæ of lead poisoning contracted many years previously.