Coal tar treated psoriasis patients were used as a model population to evaluate a panel of immunoassays for monitoring exposure to benzo[a]pyrene (BP) and related polycyclic aromatic hydrocarbons (PAH). The assays included measurement of PAH diol epoxide-DNA adducts in white blood cells by competitive enzyme-linked immunosorbent assay (ELISA) with fluorescence endpoint detection, PAH-albumin adducts by competitive ELISA with color endpoint detection and serum levels of antibodies recognizing BP diol epoxide-DNA adducts by noncompetitive color ELISA. PAH-DNA adducts by ELISA were elevated in patients (mean 6.77 +/- 12.05/10(8)) compared to controls (4.90 +/- 8.81/10(8), p = 0.12). There was no difference in PAH-albumin adducts between patients (mean 0.61 +/- 0.31 fmol/micrograms) and controls (0.63 +/- 0.30 fmol/micrograms). Glutathione S-transferase M1 genotype was also determined but no relationship was found between presence of the gene and either DNA or protein adduct levels. About 30% of both patients and controls had measurable titer of antibodies recognizing BPDE-I-DNA adducts. Measurement of white blood cell DNA adducts by ELISA was the most sensitive method for detecting PAH exposure in coal tar-treated psoriasis patients.