Cultured human epidermal cells which require no feeder layer were used to study metabolism of benzo(a)pyrene (BP) and DNA adduct formation. The cultures were prepared from a single cell suspension and maintained at a pH of 5.9-6.2. At 2 micro M BP some cell toxicity was observed, and substantial cell death occurred at 4 micro M BP. The metabolism and DNA binding of BP were followed from 6 to 48 h of incubation. High pressure liquid chromatography (h.p.l.c.) revealed that BP was metabolized into 9,10-diol,7,8-diol, quinones, phenols and tetraols of BP. The prevalence of the minor DNA adducts varies as a function of the source of the primary skin cells. These results confirm that human cells with no feeder layer metabolize BP and the resultant DNA damage is similar to that found in other mammalian systems.