Cancer mortality among workers exposed to zinc chromate paints.

To evaluate the carcinogenicity of chromium compounds among user industries, the proportionate mortality experience of spray painters exposed to zinc chromate primer paints and electroplaters exposed to chromic acid in the aircraft maintenance industry was examined. Compared to the mortality patterns of U.S. white males, no excess of cancer was found in the 48 deaths among electroplaters. Analysis of the 202 deaths among spray painters revealed a significant excess of cancer, primarily of the respiratory tract. The relative increase of respiratory cancer showed a positive gradient with the length of estimated exposure time, and was confined to painters whose interval from first employment to death was at least 20 years. The findings consistent with occupational exposure to chromium compounds, previously shown to be carcinogenic in manufacturing processes, but the effect of other paint constituents, tobacco smoking, or methodologic limitations could not be discounted.

Inhalation studies of nickel sulfide in pulmonary carcinogenesis of rats.

Two hundred twenty-six specific pathogenfree male and female F344 rats were exposed to nickel sulfide inhalations for 78 weeks (5 days/wk, 6 hr/day) and observed for an adiditional 30-week period. For the same amount of time, 214 rats were exposed to filtered room air and served as controls. Rats exposed to nickel sulfide showed a significantly higher incidence of pulmonary hyperplastic and neoplastic lesions originating from the bronchial and bronchiloo-alveloar segments. The overall incidence of lung tumors in the animals treated with nickel sulfide was 14 percent compared with 1 percent in the controls. Pulmonary inflammatory reactions were also greatly increased. Injection of an agent (hexachlorotetra-fluorobutane) that induced lung infarction did not increase the proportion of animals having lesions, nor did it alter the type of lesions found in animals exposed to nickel sulfide.