Nickel-related cancer in welders.

During stainless steel (SS) welding, solid aerosols are generated from elemental compounds which are generally considered to be human carcinogens; i.e. compounds of hexavalent chromium (CrVI) and nickel. Epidemiological studies among groups of SS-welders have indicated that they may carry a higher risk of acquiring lung cancer than mild steel (MS) welders using the same welding techniques. This excess risk has been demonstrated in cohort as well as by case-control studies. The present evidence does not support the view that exposure to SS-welding fumes poses a hazard of cancer at any other site. Exposure to asbestos and smoking are generally major confounders in these studies. The number of SS-welders world-wide seems to be increasing, thus these findings may be of significance to SS-welders and to the welding industry. Despite the information on the possible cancer hazard among SS-welders, current epidemiological data on cancer incidence and mortality do not offer clear evidence to determine whether exposure to nickel or CrVI compounds constitutes the more important risk factor for lung cancer.