The white rot fungus Phanerochaete chrysosporium degraded DDT [1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane], 3,4,3′,4′-tetrachlorobiphenyl, 2,4,5,2′,-4′,5′-hexachlorobiphenyl, 2,3,7,8-tetrachlorodibenzo-p-dioxin, lindane (1,2,3,4,5,6-hexachlorocyclohexane), and benzo[ a ]pyrene to carbon dioxide. Model studies, based on the use of DDT, suggest that the ability of Phanerochaete chrysosporium to metabolize these compounds is dependent on the extracellular lignin-degrading enzyme system of this fungus.