Cancer hazards caused by nickel and chromium exposure.

An increased risk of cancer associated with nickel refining and with chromate production has been known for some decades. The occupational exposure pattern of both nickel and chromium is very complex. Even though nickel carbonyl is an experimental carcinogen, there are no data supporting its carcinogenicity in humans. Nickel subsulfide may be the most potent carcinogen among the different nickel compounds. A correlation between lung cancer and exposure to chromates has been shown in several studies. As yet, there are no epidemiologic data indicating carcinogenicity of chromium(III) salts. Hexavalent chromium, however, has been suggested as the causative carcinogen among platers and ferrochromium workers. There is an urgent need for careful dose registration before a quantitative cancer risk analysis can be performed for the nickel and chromium industry.