PANNA: Chlorpyrifos Facts

Chlorpyrifos Facts

EPA estimates that about 20 million pounds of chlorpyrifos are applied in the U.S. every year, about half for agricultural uses, half for residential uses.

Used To Control: Insects
Top Uses: Corn, termite control, cotton
Known Health Effects: Neurotoxicity, suspected hormone disruption

Use and Exposure

Chlorpyrifos is an insecticide which is used on agricultural crops and livestock, and until very recently was used extensively in homes for pest control (mostly as a termiticide and in pet flea collars). EPA estimates that 10 million pounds of chlorpyrifos are applied agriculturally every year, half of which is applied to corn crops. Another 10 million pounds are used in non-agricultural settings, like termite control (approximately 5 million pounds) and other industrial or household settings (2). In California, more than two million pounds of chlorpyrifos were used in 2000. The top uses of chlorpyrifos in California are in structural pest control, cotton almonds, alfalfa, oranges and walnuts (3).

EPA has restricted and eliminated some non-agricultural uses of chlorpyrifos. Home use chlorpyrifos products are being phased out, with most uses banned by the end of 2002, and the remaining pre-construction uses to be phased out in 2004 and 2005. However, some residential and other non-agricultural use of chlorpyrifos will continue, including mosquito control, outdoor areas where children’s exposure is unlikely, and container baits in homes (1). Agriculturally, chlorpyrifos use on apples and grapes has been restricted and use on tomatoes was eliminated in 2000, but many uses continue.

People can be exposed to chlorpyrifos by touching treated surfaces, breathing air inside or outside treated buildings or near fields where it was applied. Exposures also result from eating food contaminated with chlorpyrifos residues (4). Contact with flea collars containing chlorpyrifos can also lead to exposure.

Health Effects

Breathing, ingesting, or touching chlorpyrifos can cause neurological effects stemming from the inhibition of cholinesterase, an enzyme necessary for the proper transmission of nerve impulses. Symptoms include excessive salivation and tearing, uncontrolled urination, weakness, nausea, vomiting, diarrhea, headaches, pinpoint pupils, confusion and dizziness. At higher doses, tremors, convulsions or respiratory paralysis may occur, sometimes leading to coma and death. There are no data suggesting that chlorpyrifos is a human carcinogen or reproductive toxicant (4). However, chlorpyrifos is a suspected endocrine disruptor. Endocrine disruptors interfere with the natural function of estrogen, androgen and thyroid hormones (3).

Companies That Manufacture Products Containing Chlorpyrifos

Dow AgroSciences LLC, Cheminova, Makhteshim-Agan, Garda, and Platte Chemical (5, 6).

References

(1) United States Environmental Protection Agency. “Chlorpyrifos Revised Risk Agreement and Agreement With Registrants.” June 2000. Available at http://www.epa.gov/pesticides/op/chlorpyrifos/agreement.pdf accessed 1/23/03.
(2) United States Environmental Protection Agency. “Chlorpyrifos Facts, EPA 738-F-01-006.” February 2002. Available at http://www.epa.gov/oppsrrd1/REDs/factsheets/chlorpyrifos_fs.htm accessed 1/17/03.
(3) Pesticide Action Network Pesticide Database. “Chemical Information About Chlorpyrifos.” Available at http://www.pesticideinfo.org/PCW/Detail_Chemical.jsp?Rec_Id=PC33392 accessed 1/22/03.
(4) Agency for Toxic Substances and Disease Registry. September 1997. “ToxFAQs(tm) for Chlorpyrifos.” Available at http://www.atsdr.cdc.gov/tfacts84.html accessed 1/17/03.
(5) United States Environmental Protection Agency. “Overview of Chlorpyrifos Revised Risk Assessment.” June 2000. Available at http://www.epa.gov/oppsrrd1/op/chlorpyrifos/overview.pdf accessed 1/23/03.
(6) Hazardous Substances Data Bank. National Library of Medicine, National Institutes of Health. “Chlorpyrifos.” Available at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB accessed 1/22/03.