Carcinogenicity Assessment of Aldrin and Dieldrin
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Evidence pertaining to the carcinogenicity of aldrin/dieldrin is reviewed and evaluated. The report covers studies completed before 1985. Case reports and epidemiologic studies of pesticide applicators and pesticide manufacturing workers are reviewed, but because of methodologic limitations, these studies established neither a positive nor a negative association between cancer and aldrin/dieldrin exposure. A number of independent studies of laboratory animals, however, demonstrated that aldrin/dieldrin cause liver cancer in mice and rats. Based on the accumulated evidence, aldrin/dieldrin are classified as probable human carcinogens, Group B2, using EPA's Guidelines for Carcinogen Risk Assessment. The carcinogenic potency of aldrin/dieldrin is estimated by fitting mathematical models to the laboratory animal data. These estimates indicate that aldrin/dieldrin are rather potent carcinogens, ranking in the second quartile of potential carcinogens evaluated by EPA's Carcinogen Assessment Group.