Polycyclic aromatic hydrocarbons (PAHs) occur widely in the environment and in everyday products such as water, soil, dust, cigarette smoke, rubber tires, gasoline, roasted coffee, baking bread, charred meat, and in many other foods. For over 200 years, carcinogenic effects have been ascribed to PAHs. In 1775, Percival Pott, an English physician, made the association between the high incidence of scrotal cancer in chimney sweeps and their continual contact with chimney soot. Research on the toxicity of PAHs, however, progressed somewhat
slowly. In 1932, benzo[a]pyrene was isolated from coal tar and found to
be highly carcinogenic in experimental animals.
