A new monograph published by the International Agency for Research on Cancer describes its evaluation of the carcinogenicity of the organochlorine insecticides gamma-hexachlorocyclohexane (lindane) and dichlorodiphenyltrichloroethane (DDT), and 2,4-dichlorophenoxyacetic acid (2,4-D), a chlorophenoxy herbicide. Based on a review of the latest available scientific literature, IARC classifies lindane as carcinogenic to humans due to “sufficient evidence” that the insecticide causes non-Hodgkin lymphoma.  IARC classifies DDT as probably carcinogenic to humans due to “sufficient evidence” that it causes cancer in experimental animals and “limited evidence” of its carcinogenicity in humans. According to the monograph, positive associations have been observed between DDT and cancers of the liver and testis, and non-Hodgkin lymphoma. IARC classifies the herbicide 2,4-D as possibly carcinogenic to humans based on “inadequate evidence” of its carcinogenicity in humans and “limited evidence” in experimental animals.  The monograph is available to download as a from IARC’s website.