The effect of 4 metal salts on the induction of chromosome aberrations and sister chromatid exchange (SCE) in cultured Chinese hamster ovary (CHO) cells was investigated. It was observed that CdCl2, NiCl2, CrO3 and HgCl2 were effective in causing various types of chromosome aberrations. The percentages of abnormalities increased with increasing doses of the metals used. These metal compounds also raised the SCE rates compared to 5-bromo-2'-deoxyuridine controls. The importance of rapid screening of potentially hazardous metals is described.