The first step in prevention of poisoning in the dye industry includes well-ventilated, properly equipped buildings. Selection of workmen is important and the use of the best methods in manufacturing. These investigations, which are based on 2,500 employees, whose blood was tested periodically, yield some minor diagnostic material. The hazards of the dye industry are those connected with any industry plus the poisonous chemicals necessarily handled in the production of dye stuffs. Prior to 1917 the making of aniline products in this country for use as dye stuffs amounted to next to nothing. Our company had, however, been making aniline products since 1907, and in no inconsiderable quantities, for use as explosives; so that while the dye industry is fairly new to us, the nature of aniline and a number of its allied products is fairly familiar. The first hazard we meet in the dye industry is from strong adds, such as nitric and sulphuric or a mixture of these two known as mixed acid. These are used to nitrate the benzine or toluene, etc. Their destructiveness to the human tissues is well known and every precaution is taken to prevent these acids from getting on the skin of the workmen. When acid does get on the workman he quickly knows it by the pain it causes, and he immediately drowns it withlwater and seeks a soothing dressing for his burn. Nitrous fumes may also be considered under this hazard and are the reddish brown fumes, nitric peroxide, together with some finely atomized acid. Exposure to these fumes must be considered in the natture of an accident and occurs
the result of a nitrator fire or a large spill. Their effects are those of an irritant to the mucous membrane of the respiratory tract and they may cause anything from slight bronchial irritation to a fatal pulmonary edema. The second hazard we meet with in the dye industry is from the products formed by the action of mixed acid on the benzene series of hydrocarbons, namely; benzene, toluene, xylene, mesitylene, cymene and hexa-methyl-benzene, forming the compounds known as the nitro aromatics, and also the hydrocarbons, napthalene and anthracene and derivatives from these. A typical nitro compound is mononitro-benzene, and a typical amido compound is aniline which is made from mono-nitro-benzene by treatment with nascent hydrogen. There are an amazing number of these nitro and amido compounds and a description of each individual compound would be impossible at this time. It is their general -character we are after and this depends largely on their physical properties, their solubility-and molecular instability. Some are clingy, oily liquids, others quite insoluble solids and from the adherent, thin, easily absorbable compounds we expect quicker poisoning than from the more stable less soluble solids. 255 as
THE AMERICAN JOURNAL OF PUBLIC HEALTH
skin, month after month and suffer no skin inflammation, while other workmen handling the same compound will show an active dermatitis in twenty-four hours. Workmen with such sensitive skins should be permanently removed from contact with such irritants. The skin of an habitual drinker of alcoholic liquor becomes easily inflamed on exposure to these chemicals. For a time periodic blood examinations were carried on at intervals of two weeks and many thousands of these examinations were made. The results of these examinations showed no great departure from normal, but there was a slight increase in the number of small lymphocytes, a small increase in the number of transitionals, and a slight increase in the number of eosinophiles. Such changes were only found in those workmen who had been exposed to nitro or amido compounds for a period of four or five weeks or longer. In acute cases there is a diminution in the amount of hemoglobin and a formation of methemoglobin. The earliest symptoms we get in the workmen are headaches, giddiness and a "down and out feeling," as...