Document OEao5N16RN3qexYr9aKrJgEnK

16P FROM: TO:16182590896 164 OU$l DISEASES, EXCLUDING THE HBR0T1C PNUUMOCONlOSGS a impounds, at least, must be added to the list ot' substances which may cause cancer of the respiratory tract. Association of pulmonary cancer with silicosis and asbestosis Between 1930 and 1940 there were several papers calling attention to a suspected association between lung cancer and silicosis, the inference being that silica might, directly or indirectly, play some aetiologies! part in producii g the malignant disease. Such an association has not been borne out by farther inquiry. The relation between asbestosis und lung cancer is, however, quite different. his subject is dealt with in Chapter I of this volume New and unknown Industrial carcinogens In the future there may be new and increased usage of certain materials now known to be carcinogenic. This is true ul the present lime for radioastive,materials, especially isotopes, and tor x-rays. Furthermore) as our Knowledge of the aetiology of malignant disease of the respiratory tract increases, it is to be expected that other materials which are now oncounlored in the industrial environment, as well, perhaps, as some in the domestic environment, will prove to have carcinogenic properties. New uses for some ojf the rarer mcluls ure continually being found and the toxicology of many or these is incompletely known. Substance* carcinogenic to animals.--Some substances, not yet known to produce cancer in human beings, have been shown to induco malignant changes in animals. Beryllium is one of these, intravenous injections having been reported, both in Oroat Britain (Barnes, 1949) and in America (Gardner and Heslington, 1946; Dutra and Largent, 19S0), as causing sarcoma of bones. Animal experiments have also shown that selenium is carcinogenic for certain species, although no human caso attributed to its industrial posure is known. TMineral oils. -Uncertainly exists about exposure to mists of mineral oils, epcounlered by garage workers and in other occupations. Kennaway and I^ennaway (1936) note that spinners and piecers of cotton, who are exposed to fine droplets of mineral oil, have a very low ratio (31) for lung cancer, but a rather high ratio (148) for laryngeal cancer. Hueper (1951) mentions /re-propyl oil, as requiring further study in regard to cancer of ihe nasal sinuses and lungs, in tho manufacture of /re-propyl alcohol. Santo (1949) summarizes available knowledge concerning the reaction of the lungs to the instillation of various types of oil. He says that mineral ails may produce net only acute lipoid pneumonia but chronic granulomatous infiltrations or paraffinomas. He presents 2 cases of bronchial carcinoma in patients who had been taking liqdid paraffin dally by tho mouth ovor a period of years. In 1 case organizing lipoid pneumonia was present throughout the affected area, and in the other the carcinoma appeared to have arisen in such an