Arsenic and respiratory cancer in man: an occupational study.

To clarify the role of arsenic in human carcinogenesis, the mortality experience of 8,047 white male smelter workers exposed to arsenic trioxide during 1938-63 was studied and compared with that of the white male population of the same States. Smelter workers had an excess total mortality, due mainly to malignant neoplasms of the respiratory system and diseases of the heart. The threefold increase in respiratory cancer was analyzed in relation to the length of employment and degree of exposure to arsenic, sulfur dioxide, and other elements in the smelter. The excess of respiratory cancer was as high as eightfold among employees who worked more than 15 years and who were heavily exposed to arsenicj it showed a gradient in proportion to the degree of exposure to arsenic and sulfur dioxide. The findings support the hypothesis that inhaled arsenic is a respiratory carcinogen in man, but an inRuence of sulfur dioxide or unidentified chemicals, varying concomitantly with arsenic exposure, cannot be discounted.-J Nat Cancer Inst 42: 1045-1052,1969.