Experimental results with percutaneous applications of automobile exhaust condensates in mice.

The induction of squamous-cell carcinoma and papillomas in mice after 80 weeks' skin painting with different doses of automobile exhaust condensates and their fractions is described. The results demonstrate that the carcinogenic activity of the condensate resides in its polycyclic aromatic hydrocarbon fractions. Benzo[a]pyrene accounts for approximately 9% of the activity of the condensate. The sebaceous gland suppression test, used as a screening method, is predictive of carcinogenicity and is positive for those condensate subfractions which contain carcinogenic PAH.