Chlorpyrifos
chemical compound
Chlorpyrifos (CPS), also known as chlorpyrifos ethyl, is an organophosphate pesticide that has been used on crops, animals, in buildings, and in other settings, to kill several pests, including insects and worms. It acts on the nervous systems of insects by inhibiting the acetylcholinesterase enzyme. Chlorpyrifos was patented in 1966 by Dow Chemical Company.
Chlorpyrifos is considered moderately hazardous to humans (Class II) by the World Health Organization based on acute toxicity information dating to 1999. Exposure surpassing recommended levels has been linked to neurological effects, persistent developmental disorders, and autoimmune disorders. Exposure during pregnancy may harm the mental development of children.
In the United Kingdom, the use of chlorpyrifos was banned as of 1 April 2016 (with one minor exception).
As of 2020, chlorpyrifos and chlorpyrifos-methyl were banned throughout the European Union, where they may no longer be used. In May 2025, the EU listed chlorpyrifos as a persistent organic pollutant (POP) under the Stockholm Convention on Persistent Organic Pollutants.
As of August 18, 2021, the U.S. Environmental Protection Agency (EPA) announced a ban on the use of chlorpyrifos on food crops in the United States.
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Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Aug 19, 2026. The linked authority identifier is Q414915. The first chronological checks are 1966, 1999, 2016 and 2020.
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This entry incorporates text from “Chlorpyrifos” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.