The carcinogenicity of chromium (7440473) was examined among the workers of a chromate facility. Information for the 332 employees first hired between 1931 and 1937 was obtained from personnel records and previous research. Mortality was followed through 1993. Of the total deaths, confirmed for 85% of the workers, 36.0% were attributed to cancer, while 23.3% were attributed specifically to lung cancer. The mortality rates for lung cancer progressed markedly with time, from a rate of 86.3 deaths per 100,000 workers with less than 15 years of observation to a rate of 762.4 deaths per 100,000 workers with less than 63 years of observation. Considering that workers first hired when less than 25 years of age were most difficult to find, the age specific lung cancer mortality rate calculated for this group, 425.0 deaths per 100,000, was regarded as an underestimate. The lung cancer mortality rate for the 1931 to 1932 subcohort, the most complete grouping, was 1,203.4 deaths per 100,000 workers for the 25 to 29 years age group. For the overall cohort, the age specific lung cancer mortality rates ranged from 379.7 deaths per 100,000 workers for the 40 to 44 years age group to 1,492.5 deaths per 100,000 workers for the 55 to 59 years age group. The age adjusted lung cancer mortality rates increased steadily with increasing total, insoluble, and soluble chromium exposures. Although greater risk was associated with soluble chromium at lower exposure levels, greater risk was associated with insoluble chromium at higher exposure levels. The author concludes that lung cancer risk is not confined to exposure to only one form of chromium.

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