Nickel in welding fumes--a cancer hazard to welders? A review of epidemiological studies on cancer in welders.

Although the high exposures to metallic aerosols that were formerly encountered in the primary nickel industry are no longer prevalent, large occupational groups, such as welders, are currently exposed to moderate levels and may therefore be at some degree of health risk. Examination of the world literature reveals a number of epidemiological studies which demonstrate a slight excess risk of respiratory tract cancer incidence among the general welding population. Several of these studies are suggestive of the possibility that there may be a larger excess risk exclusively limited to those welding cohorts who are exposed to nickel and chromium in the fumes from the welding of stainless and high alloy steels. Such a hypothesis, although supported in part by in vitro and in vivo genotoxicity tests, can only be verified by international collaboration in specifically designed epidemiological studies using a uniform protocol.