Mortality in Chromium Chemical Production Workers: a Prospective Study

Abstract

Mortality among male employees was studied in a chromium chemical production plant, part of which was rebuilt in 1950-51 and the remainder in 1960, to reduce exposure to chromium bearing dusts. Of 2 101 employees initially employed between 1945 and 1974 and having worked at least 90 days, the vital status of 88% was ascertained, as of mid-1977. Lung cancer mortality for hourly workers initially employed between 1945 and 1959 was significantly higher than in the comparison Baltimore City population (SMR = 2.0), yet it was lower than that reported in previous studies of this industry. A dose response effect was evident from the relationship between duration of employment and mortality. The lung cancer mortality among those employed for three or more years exclusively in the new facility was similar to that observed for such long-term workers in other parts of the plant. Specific job positions were examined. A history of employment in the Bichromate and Special Products Department (production of chromic acid and other products), known as the 'wet end', was associated with the increased lung cancer mortality in contrast to the Mill and Roast Department, known as the 'dry end'. Because of the long latency period associated with chromium exposure and cancer, it was not possible to adequately assess the risk of cancer for workers initially employed after 1960. Methodological issues related to these findings are discussed.