We have undertaken a study among coke-oven workers to test the feasibility of an enzyme-linked immunosorbent assay with anti-trans-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahy-dro-benzo[a]pyrene-DNA antibodies for monitoring occupational exposure to poly cyclic aromatic hydrocarbons (PAH). Coke-oven workers are occupationally exposed to relatively high levels of PAH and are at increased risk for lung cancer. Three blood samples were collected from each of the 56 coke-oven workers exposed to PAH and 44 unexposed workers employed in a steel-rolling factory of the same plant. In addition, PAH levels were measured in ambient air by personal sampling, and the excretion of 1-hydroxypyrene in urine was also measured on 3 consecutive working days. All participants were interviewed regarding working conditions, personal hygiene, and smoking habits. The results showed that the coke-oven workers were exposed to substantial concentrations of atmospheric PAH [1-186 μg/m3), including benzo[a]pyrene (0.1-7.8 μg/m3) and pyrene (0.6-23.6 μg/m3). Both benzo[a]pyrene and pyrene were shown to be representative for the whole group of PAH. Forty-seven percent of the coke-oven workers had detectable levels of PAH-DNA adducts in their white blood cells, compared with 30% of the controls. In both groups, smokers had significantly higher levels of PAH-DNA adducts than did nonsmokers. At one site, we found the correlation positive between DNA adducts and the duration of exposure (r= .47, p= .005). Generally, the correlation was not significant between PAH-DNA adducts in blood and the concentration of PAH in the air and 1-hydroxypyrene in urine. [J Natl Cancer Inst 82: 927-933, 1990] © 1990 Oxford University Press.