US EPA "Kills Pesticide Dead"
Cites Risk of Neurological Damage by Chlorpyrifos

June 13, 2000

A Pesky Problem

Ants, termites, ticks, fleas and cockroaches: they all have their place in nature. That's where they belong - outside, in nature. When these and other bugs invade our homes or infest our pets, we consider them pests. Pests such as cutworms, aphids and maggots damage food crops. Other bugs, such as mosquitoes and certain flies, can transmit disease to livestock and humans. To protect us, our pets and our food supply from these pests, researchers have developed many pesticides to kill them.

Let's Spray!

Some pesticides belong to a group of chemicals called organophosphates. These chemicals are classified as "neurotoxins" because they target and poison the nervous system. Specifically, organophosphates target the acetylcholine neurotransmitter system. Organophosphates inhibit an enzyme called acetylcholinesterase which breaks down acetylcholine into acetate and choline. Therefore, in the presence of organophosphate pesticides, acetylcholine increases because it is not being broken down. This results in overactivation of the acetylcholine system which may cause symptoms such as nausea, dizziness, and respiratory paralysis in humans; high doses of this poison can even cause death. Many nerve agents (chemical weapons) also cause illness and death by inhibiting acetylcholinesterase.

The Solution Creates a Problem

Sometimes the solution to a problem creates another problem. In the case of pesticides, some chemicals that kill insects pose a danger to the health of humans. This may be true for one organophosphate pesticide called chlorpyrifos. Chlorpyrifos is a chemical found in more than 800 products, including "Dursban," the most widely used home insecticide in the US. In addition to its use in the home, chlorpyrifos is used:

  • Inside, to control cockroaches, fleas, spiders and ticks.
  • Outside,
    • to kill mosquitoes, spiders and ticks
    • to protect fruit, nut and vegetable crops from pests such as aphids, mites and cutworms.
    • on lawns and in gardens to control ants, crane flies, chinch bugs.

The US EPA Acts

Because of its potential danger to humans, chlorpyrifos has been banned for home and garden use by the US Environmental Protection Agency (EPA). On June 8, 2000, EPA administrator Carol M. Browner announced that chlorpyrifos will be:

  1. eliminated from home, lawn and garden use by the end of 2000.
  2. eliminated for controlling termites in homes by the end of 2000.
  3. eliminated from use in schools, day care facilities, parks, hospitals, nursing homes and malls by the end of 2000.
  4. reduced on food by the next growing season.
  5. eliminated for controlling termites on new construction by the end of 2004.

The EPA stated that the main reason for the ban was to protect children from exposure to chlorpyrifos. Although the EPA says that chlorpyrifos is linked to neurological damage, Dow Chemical, the company that makes Dursban, disagrees. In a news release on June 8, 2000, Dow Chemical stated that over 3,600 studies and reports show that chlorpyrifos products "provide wide margins of safety for both adults and children." Nevertheless, Dow Chemical has agreed to follow the ban on chlorpyrifos.

The Future - Safety Rules!

Even with the ban on chlorpyrifos, you, your family, home and school will still be safe from an invasion of ants, mosquitoes, termites and other pests. There are plenty of other chemicals without chlorpyrifos that can still "do the job."

References and further information:

  1. Summary of Chlorpyrifos Uses and Risks - from US EPA
  2. Nerve Agents - from Neuroscience for Kids

GO TO: Neuroscience In The News Explore the Nervous System Table of Contents

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