The International Agency for Research on Cancer (IARC) is a specialized agency of the World Health Organization that focuses on cancer. IARC has evaluated the carcinogenicity of three pesticides: lindane (gamma-hexachlorocyclohexane), DDT (dichlorodiphenyltrichloroethane), and 2,4-D (2,4-dichlorophenoxyacetic acid). The evaluation is published as Volume 113 of the IARC Monographs.
Lindane was classified as carcinogenic to humans (Group 1) based on sufficient evidence in humans that lindane causes non-Hodgkin lymphoma. Use of lindane is banned or restricted in most countries. It is no longer used in Canada for agricultural purposes.
DDT was classified as probably carcinogenic to humans (Group 2A), based on sufficient evidence in experimental animals that DDT causes cancer, and limited evidence in humans. In humans, associations have been found between DDT exposure and non-Hodgkin lymphoma, testicular cancer, and liver cancer.
2,4-D was classified as possibly carcinogenic to humans (Group 2B), based on inadequate evidence in humans and limited evidence in experimental animals. 2,4-D is one of the most widely used herbicides in North America.