About 70% of insecticides (pesticides that kill insects) used in the
United States are organophosphorous (OP) pesticides. Fruits and
vegetables that are conventionally grown with OP pesticides that are
most commonly eaten by children include peaches, apples, grapes, green
beans, and pears. (source: www.foodnews.org)
Other top uses of OP pesticides include corn, cotton, wheat, other
field crops, and for termite and mosquito control. Certain pest control
products for cats and dogs contain OP compounds.
OPs are chemically similar to the chemical warfare agents originally produced during World War II, and they work by interfering with the nervous system of insects, as well as humans, other mammals, birds, and fish. OPs block production of an enzyme called cholinesterase (ChE), which ensures that the chemical signal that causes a nerve impulse is halted at the appropriate time. Symptoms of exposure include nausea, headaches, twitching, trembling, excessive salivation and tearing, inability to breathe because of paralysis of the diaphragm, convulsions, and at higher doses, death.
OPs are among the most acutely toxic pesticides, with most of these chemicals classified by the U.S. Environmental Protection Agency as toxicity class I (highly toxic) or toxicity class II (moderately toxic). In addition, some OP pesticides cause developmental or reproductive harm, some are carcinogenic, and some are known or suspected endocrine disruptors. Detailed information on specific OP pesticides is available in Pesticide Action Network’s internet database.
OPs of primary concern include: azinphos-methyl (product name Guthion), chlorpyrifos (products Lorsban and Dursban), diazinon (product name Spectracide), dichlorvos (DDVP), dimethoate, ethephon, malathion, methamidophos, naled, and oxydemeton-methyl. Residential uses of chlorpyrifos and diazinon were recently banned by the U.S. Environmental Protection Agency (EPA).