It could be lurking in your pantry, in your attic, or in your basement. Or maybe it's lingering out back in the shed, the imaginary fortress where the kids sneak off to play. And if the family pet wears a flea collar, it may actually be seeping into your skin.
"It" is dichlorvos, a chemical relative of the deadly nerve gases sarin and VX, developed by chemical weapons engineers during World War II. Today you'll find it in vapor-releasing pest strips hung in dank, buggy places; in aerosol "bug bombs" used to fumigate insect-infested rooms; and in flea collars, which gas pests in an animal's fur. Also known as DDVP, dichlorvos is manufactured by Amvac, a California-based company, and sold under brand names such as No-Pest and Swat Pest Strip.
Dichlorvos knocks out insects by inhibiting cholinesterase, an enzyme that activates an essential neurotransmitter in the central nervous system. To understand just how essential cholinesterase is to a healthy nervous system -- in humans as well as in insects -- consider this: Sarin and VX kill people within minutes by knocking out that very same enzyme.
Inhaling dichlorvos vapor can trigger dizziness, sweats, nausea, and vomiting; high doses or prolonged exposure to low levels can cause irregular breathing and heart function and, in extreme cases, death. Small children, whose nervous systems are still developing, are especially vulnerable: A child who hugs a dog wearing a flea collar that contains dichlorvos could be exposed to 21 times the safety limit set by the Environmental Protection Agency (EPA), which classifies the chemical as a probable human carcinogen. Several European nations have banned its use.
Using pest strips and bug bombs is "like gassing your own house," says Gina Solomon, a medical doctor and NRDC senior scientist. "These organophosphates are dinosaur chemicals, most of which have been replaced by safer alternatives."
But not dichlorvos. Indeed, the problems in regulating this chemical reflect a worrisome trend. The EPA announced in May that it would restrict some home applications and require new labeling for the controversial pesticide. The agency failed, however, to take it off the market entirely despite several studies over the past two decades indicating that the chemical was too toxic to be used in the home.
In the late 1980s, the EPA began a comprehensive study of dichlorvos, citing its potential to harm humans. A preliminary report issued in 1995 stated that all household uses should be banned. But that never happened. The agency revisited dichlorvos safety again in 2002, when it was required by law to reevaluate the most dangerous pesticides on the market. Steven Johnson, then the assistant administrator of the EPA, told the Associated Press that the agency was seriously considering banning dichlorvos. But again, nothing happened.
NRDC attorneys suspected that Amvac, the manufacturer, had been too closely involved in the regulatory process but had no evidence to prove it. Then, in January 2005, NRDC received a stack of documents from the EPA in response to a Freedom of Information Act lawsuit filed after the agency refused to turn over records related to the regulation of another pesticide, atrazine. Atrazine is made by Syngenta and is one of the most widely used agricultural weed killers, applied to about two-thirds of all corn grown in the United States. Syngenta executives held more than 40 private meetings with EPA officials while the agency was reviewing atrazine safety data. Despite numerous scientific studies documenting widespread groundwater contamination and health risks, the EPA has allowed atrazine to remain on the market.
In the files turned over by the EPA, NRDC attorneys discovered correspondence between agency officials and Amvac over dichlorvos regulation. One group of documents revealed threats made by Amvac lawyers in 2002 to sue individual EPA employees if they continued to talk publicly about the dangers of dichlorvos.
NRDC filed suit against the EPA in February 2005, arguing that its private dealings with Amvac violated the Freedom of Information Act and the agency's own rules. The case against Amvac was dismissed on a technicality: The EPA had not yet issued its final regulatory decision so it was too soon to sue. In June, the agency announced its decision to allow many dichlorvos-containing products to remain on the market. NRDC's appeal will now be heard. In the meantime, NRDC has petitioned the EPA to eliminate all home uses of dichlorvos.
"Amvac ran a whole campaign to make sure dichlorvos stayed on store shelves," Solomon says. "The company bullied
-- Laura Wright