In 24 manual metal arc stainless steel welders (means: exposure time 19 years, 100 electrodes/d, air chromium level 81 micrograms/m3, urinary chromium 47 mumol/mol creatinine) and 24 matched referents, lymphocytes in peripheral blood were analyzed for cytogenetic effects. No statistically significant differences were observed as to frequency of cells with breaks and fragments (1.5% for the welders, 1.9% for the referents); gaps and isogaps (1.8 vs 2.0%); interchanges, dicentrics, rings and markers (0.8 vs 0.5%); total number of cells with structural aberrations (4.1 vs 4.4%); hyperdiploidy (0.3 vs 0.2%); or total number of cells with aberrations (4.4 vs 4.6%). Neither were there any differences in the frequencies of micronuclei (7.8 vs 7.9 per mille) or sister chromatid exchanges (11 vs 12 per cell) in lymphocytes of peripheral blood.