A retrospective cohort study of mortality among stainless steel welders.

Hexavalent chromium particles are generated in the welding of stainless steel. These particles have manifested a mutagenic action in bacterial test systems and produced chromosome aberrations in cultured Chinese hamster cells. Welders who had welded stainless steel for more than 5 a during 1950--1965 were selected for this study. According to an earlier survey the hexavalent chromium exposure of such welders was often about 50 microgram/m3 (calculated as CrO3). The cohort was followed until December 1977. The expected number of deaths was calculated from cause-, gender-, age-, and year-specific death rates of the general population in Sweden. In the cohort, consisting of 234 welders, the observed numbers of total deaths and deaths caused by tumors were the same as the expected numbers. However, three welders had died of pulmonary tumors in comparison to the expected number of 0.68 (p = 0.03).