Induction of pulmonary DNA adducts by benz(a)anthracene (56553) (BA), dibenz(a,h)anthracene (53703) (DBA), dibenzo(a,i)pyrene (189559) (DBP), and dibenz(a,h)acridine (226368) (DBAC) was studied in rats. Induction of sister chromatid exchanges (SCEs) and micronuclei in lung cells was also investigated. BA, DBA, DBP, and DBAC were selected as being representative of byproducts found in coke oven emissions and other industrial emissions and wastes. Male Sprague-Dawley-rats were administered up to 100mg/kg BA, 34.10mg/kg DBA, 10.0mg/kg DBP, or 100mg/kg DBAC intratracheally three times over a 24 hour period. They were then killed and lung cell suspensions were prepared. Lung cell DNA was extracted and analyzed for adducts using the phosphorus-32 post labeling/thin layer chromatography assay. The lung cells were scored for SCEs and micronuclei. DBP and DBAC each induced a single DNA adduct. BA and DBA induced formation of three and two adducts, respectively. Based on the concentrations tested, DBP was the most potent inducer of DNA adducts, followed by DBA, BA, and DBAC. All compounds induced formation of SCEs and micronuclei. DBP was the most potent inducer of SCEs. The minimum concentrations for inducing SCEs and micronuclei were higher than the minimum doses required to induce DNA adducts for all four compounds. The authors conclude that BA, DBA, DBP, and DBAC are rat pulmonary genotoxicants. The rat lung cell DNA adduct assay is more sensitive for detecting pulmonary genotoxicity of these compounds than SCE or micronuclei assays.