Chlorpyrifos is an organophosphate pesticide used to kill a number of pests including insects and worms. It is used on crops (such as apples, corn, soybeans and Christmas trees), animals, and buildings. It was introduced in 1965 by Dow Chemical Company. It acts on the nervous system of insects by inhibiting acetylcholinesterase. It has been sold under the brand names Lorsban, Dursban, and others,
The Environmental Protection Agency phased the pesticide out of household use in 2000. It is still allowed in commercial agriculture. Currently, chlorpyrifos remains registered as it undergoes registration review, a program that re-evaluates all pesticides on a 15-year cycle. Registration review ensures pesticides will not cause unreasonable adverse effects when used according to label directions and precautions and that there is a reasonable certainty of no harm from dietary and residential exposure. All documents related to the registration review can be located in the registration review docket EPA-HQ-OPP-2008-0850 located at www.regulations.gov.
People exposed to the pesticide during its use or by drift carried by wind report the immediate symptoms can include nausea, vomiting, diarrhea, abdominal cramps, muscle weakness, muscle twitching, coughing, and wheezing.
There are also concerns of developmental effects in children and in the fetus during pregnancy
Chlorpyrifos also has harmful effects on aquatic life and bees. Aquatic crustaceans and insects appear to be more sensitive to acute exposure than are fish. Concentrated chlorpyrifos released into rivers killed insects, shrimp and fish. In Britain, the rivers Roding
Exposure to chlorpyrifos can be toxic to bees as well.
Food residues: The EPA proposed to eliminate all tolerances for chlorpyrifos ("Because tolerances are the maximum residue of a pesticide that can be in or on food, this proposed rule revoking all chlorpyrifos tolerances means that if this approach is finalized, all agricultural uses of chlorpyrifos would cease.") and asked for comments. The Dow Chemical Company is actively opposed to tolerance restrictions on chlropyrifos and is currently lobbying the White House to, among other goals, pressure EPA to reverse its proposal to revoke chlorpyrifos food residue tolerances.
February 2019: The 9th U.S. Circuit Court of Appeals will hear a case against the EPA on March 25, 2019 to determine whether the EPA has to ban it.
EPA scientists recommended a total ban on the chemical.