Birth defect - A physical or biochemical defect (as cleft palate, phenylketonuria, or Down syndrome) that is present at birth and may be inherited or environmentally induced.

Reproductive toxicant - Substance or preparation that produces non-heritable adverse effects on male and female reproductive function or capacity and on resultant progeny.


Despite extensive use of the product for more than 45 years, there is no credible scientific information that would substantiate a claim that chlorpyrifos causes birth defects. The U.S. Environmental Protection Agency, the U.S. Centers for Disease Control, the World Health Organization, and many other regulatory authorities worldwide have evaluated decades of research on chlorpyrifos and have not found birth defects or reproductive toxicity to be plausible outcomes of exposures from authorized use. Dow AgroSciences strongly disagrees with the decision by the California Developmental and Reproductive Toxicity Identification Committee (DART IC) in late 2017 to list chlorpyrifos under Proposition 65 as a developmental toxicant. Dow AgroSciences Statement on Chlorpyrifos and California Proposition 65

Further Resources

Breslin, W.J. et al. “Evaluation of the developmental and reproductive toxicity of chlorpyrifos in the rat.” Fundamental and Applied Toxicology, 1996, Volume 29(1):119-30.

Maurissen, J.P. et al. “Lack of selective developmental neurotoxicity in rat pups from dams treated by gavage with chlorpyrifos. “ Toxicological Science, 2000, Volume 57(2):250-63.

U.S. Department of Health & Human Services. Environmental Health & Toxicology site. IUPAC glossary:

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