Mortality in two cohorts of welders exposed to high- and low-levels of hexavalent chromium.

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. A cohort consisting of 234 welders working on stainless steel and exposed to high levels of chromium was selected. According to an earlier survey the hexavalent chromium exposure of such welders was often above 20 micrograms/m3. Another cohort consisting of 208 railway track welders exposed to low levels of chromium was also selected. The participants of both cohorts had welded for at least five years some time between 1950 and 1965 and were followed for mortality until December 1984. Among the welders exposed to high chromium levels five deaths occurred due to pulmonary tumors. This number is significantly greater than the one death that occurred among the welders exposed to low levels of chromium, but not significantly greater than the corresponding mortality of the general population. Thus exposure to stainless steel welding fumes might be associated with an increased incidence of pulmonary tumors.