Investigation of cancer epidemiology and study of carcinogenic agents in the Shanghai Rubber Industry.

Preliminary studies on crude cancer incidences among workers from 89 factories in Shanghai revealed excessive risk of cancer for workers in certain workshops of rubber tire factories. Chronic in situ animal exposures showed that compounding and Banbury mills for mastication and mixing were origins of carcinogenic contaminants. Various chronic experiments indicated the carcinogenicity of PBNA in rats and mice, especially with regard to the lungs. The high concentration of PBNA in the atmosphere of the work area seemed to be related to the excessive incidence of lung cancer among the workers. Epidemiological investigation showed that there was an excessive number of cases of lung cancer in the workshop of rubber tire factories where compounding, mixing, and milling took place.