Benzo[a]pyrene (BaP 3 4-Benzopyrene 3 4-Benzpyrene Benzo[def]chrysene) is a procarcinogenic polyaromatic hydrocarbon (PAH) found in coal tar and other byproducts from the combustion of organic material. It is metabolized by cytochrome P450 1A1 (CYP1A1) to benzo[a]pyrene-7 8-dihydrodiol-9 10-epoxide which is carcinogenic. This metabolite intercalates DNA thus disrupting DNA copying and inducing mutations. Benzo[a]pyrene is used as a chemical carcinogen in cancer models.