Weight of the evidence on the human carcinogenicity of 2,4-D

M. A. Ibrahim, G. G. Bond, T. A. Burke, P. Cole, F. N. Dost, P. E. Enterline, M. Gough, R. S. Greenberg, W. E. Halperin, E. McConnell, I. C. Munro, J. A. Swenberg, S. H. Zahm, J. D. Graham

Research output: Contribution to journalArticle


The phenoxy herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is widely used to control the growth of weeds and broadleaf plants. We convened a panel of 13 scientists to weigh the evidence on the human carcinogenicity of 2,4-D. The panel based its findings on a review of the toxicological and epidemiological literature on 2,4-D and related phenoxy herbicides. The toxicological data do not provide a strong basis for predicting that 2,4-D is a human carcinogen. Although a cause-effect relationship is far from being established, the epidemiological evidence for an association between exposure to 2,4-D and non-Hodgkin's lymphoma is suggestive and requires further investigation. There is little evidence of an association between use of 2,4- D and soft-tissue sarcoma or Hodgkin's disease, and no evidence of an association between 2,4-D use and any other form of cancer. Scientists on the panel were asked to categorize 2,4-D as a 'known,' 'probable,' 'possible,' or 'unlikely' carcinogen or as a noncarcinogen in humans. The predominant opinion among the panel members was that the weight of the evidence indicates that it is possible that exposure to 2,4-D can cause cancer in humans, although not all of the panelists believed the possibility was equally likely: one thought the possibility was strong, leaning toward probable, and five thought the possibility was remote, leaning toward unlikely. Two panelists believed it unlikely that 2,4-D can cause cancer in humans.

Original languageEnglish (US)
Pages (from-to)213-222
Number of pages10
JournalEnvironmental health perspectives
StatePublished - Dec 1 1991
Externally publishedYes

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

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    Ibrahim, M. A., Bond, G. G., Burke, T. A., Cole, P., Dost, F. N., Enterline, P. E., Gough, M., Greenberg, R. S., Halperin, W. E., McConnell, E., Munro, I. C., Swenberg, J. A., Zahm, S. H., & Graham, J. D. (1991). Weight of the evidence on the human carcinogenicity of 2,4-D. Environmental health perspectives, 96, 213-222.