Benzo[a]pyrene is a polycyclic aromatic hydrocarbon found in coal tar with the formula C₂₀H₁₂. Its metabolites are mutagenic and highly carcinogenic, and it is listed as a Group 1 carcinogen by the IARC. The compound is one of the benzopyrenes, formed by a benzene ring fused to pyrene, and is the result of incomplete combustion at temperatures between and .