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Chlorpyrifos

Technical Fact Sheet

As of 2011, NPIC stopped creating technical pesticide fact sheets. The old collection of technical fact sheets will remain available in this archive, but they may contain out-of-date material. NPIC no longer has the capacity to consistently update them. To visit our general fact sheets, click here. For up-to-date technical fact sheets, please visit the Environmental Protection Agency’s webpage.

Chemical Class and Type:

Molecular Structure -
Chlorpyrifos

Physical / Chemical Properties:

Uses:

Regulatory changes have occurred since this fact sheet was written. Chlorpyrifos is no longer used on food or animal feed as of 2022. The U.S. Environmental Protection Agency determined that the risks of dietary exposure to chlorpyrifos, especially in children, were too high. Products containing chlorpyrifos may still be used on non-bearing fruit or nut trees that will not bear fruit or nuts within a year. Ear tags may still be used on cattle that will not be slaughtered for at least a year.

Mode of Action:

Target Organisms

Non-target Organisms

Acute Toxicity:

Oral

Dermal

Inhalation

Signs of Toxicity - Animals

Signs of Toxicity - Humans

Chronic Toxicity:

Animals

Humans

Endocrine Disruption:

Carcinogenicity:

Animals

Humans

Cancer: Government agencies in the United States and abroad have developed programs to evaluate the potential for a chemical to cause cancer. Testing guidelines and classification systems vary. To learn more about the meaning of various cancer classification descriptors listed in this fact sheet, please visit the appropriate reference, or call NPIC.

Reproductive or Teratogenic Effects:

Animals

Humans

Fate in the Body:

Absorption

Distribution

Metabolism

Excretion

Medical Tests and Monitoring:

The "half-life" is the time required for half of the compound to break down in the environment.

1 half-life = 50% remaining
2 half-lives = 25% remaining
3 half-lives = 12% remaining
4 half-lives = 6% remaining
5 half-lives = 3% remaining

Half-lives can vary widely based on environmental factors. The amount of chemical remaining after a half-life will always depend on the amount of the chemical originally applied. It should be noted that some chemicals may degrade into compounds of toxicological significance.

Environmental Fate:

Soil

Water

Air

Plants

Indoor

Food Residue

Ecotoxicity Studies:

Birds

Fish and Aquatic Life

Terrestrial Invertebrates

Regulatory Guidelines:

Date Reviewed: August 2009; limited revisions August 2023

Please cite as: Christensen, K.; Harper, B.; Luukinen, B.; Buhl, K.; Stone, D. 2009. Chlorpyrifos Technical Fact Sheet; National Pesticide Information Center, Oregon State University Extension Services. http://npic.orst.edu/factsheets/archive/chlorptech.html.

References:

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