Notification and risk assessment for bladder cancer of a cohort exposed to aromatic amines. III. Mortality among workers exposed to aromatic amines in the last beta-naphthylamine manufacturing facility in the United States.

A retrospective cohort mortality study was conducted among workers employed at the last facility in the United States that manufactured beta-naphthylamine (BNA), a recognized human bladder carcinogen. This study was conducted in conjunction with a pilot project in which workers were notified of the health risks associated with exposures to carcinogenic amines. Cause-specific mortality for 1,312 male workers employed between 1940 and 1972, and followed through 1979, was compared with the mortality of the general population in the United States. Two deaths from bladder cancer were observed while 0.7 such deaths were expected. Due to the use of these potent carcinogenic amines, it had been anticipated that more bladder cancer deaths would be found in this population. The reasons for the small number of bladder cancer deaths could have been the low percentage of the work force exposed, an inadequate latency period, and/or the high survival rate for bladder cancer. In fact, a notification and medical screening project recently conducted in this same population found an additional 11 bladder cancer cases. This suggests that mortality may not always be an adequate indicator of disease risk.