Bladder cancer in dye manufacturing workers.

Results of an occupational analysis of chemical dye workers, using data from a larger case-control study of bladder cancer in West Yorkshire, England, are presented. The current nature of the risk of bladder cancer experienced by such workers is assessed on an unmatched case-control basis. The results indicate that the bladder cancer risk has peaked for workers exposed to arylamines, but that they still experience a twofold to threefold increased risk even after adjustments for age and smoking. A dose-response relationship is demonstrated, linked to the number of years of occupational exposure. However, results obtained under stratification, commensurate with the dates of introducing revised working practices, indicate that the calendar years during which exposure occurred are more important, in relation to increased bladder cancer risk, than is length of exposure.