Oxidative damage to DNA has been suggested to contribute to a number of diseases including cancer. In order to study the relationship between oxidative damage to DNA and occupational exposures, urinary excretion of the oxidative DNA adduct, 8-hydroxydeoxyguanosine (8-OHdG), was determined in asbestos workers, rubber workers, azo-dye workers and controls. Levels of 8-OHdG in urinary samples were quantified by automated coupled-column high-performance liquid chromatography with electrochemical detection (HPLC-EC). The registered 8-OHdG levels were 1.40 +/- 0.56 mumol/mol creatinine in asbestos workers, 1.48 +/- 0.57 in rubber workers, 1.92 +/- 0.85 in azo-dye workers and 1.07 +/- 0.41 in controls (means +/- SD). Thus, 8-OHdG levels appeared to be significantly higher (p < 0.05) in each of the exposed groups than in the control group. Regression analysis revealed no important association between 8-OHdG excretion, age and smoking. These findings suggest that occupational exposures may contribute to an increased oxidative damage to human DNA and point to the possible use of urinary 8-OHdG assays in biomonitoring of biological effects of chemicals in selected industrial workplaces.