Beginning today, consumers can no longer buy one of the most popular lawn and garden insecticides of all time.
Retailers in the United States are prohibited from selling diazinon, a highly effective killer of a variety of yard pests such as ants and grub worms. The U.S. Environmental Protection Agency phased out residential use of the chemical, which can damage the nervous system, after determining that it poses a human health risk, particularly to children.
The diazinon ban is part of an EPA program begun under the Clinton administration to scale back the most toxic pesticides, the organophosphates that have been popular for decades because they wipe out a broad spectrum of insects. It is still legal to use diazinon on some crops.
A powerful neurotoxin, diazinon is highly poisonous to fish, birds and other wildlife -- a single granule can kill a small bird -- and it is one of the most commonly found pesticides contaminating air, rain and water.
An ingredient in hundreds of home and garden products, about 13 million pounds of diazinon have been used yearly in the United States, 80% for residential uses.
Tens of thousands of households could still be storing diazinon products in their garages. Old supplies remain legal for consumers to use as long as the directions on the label are followed.
The EPA gave nurseries, hardware stores and other retail outlets four years' notice for the ban, and manufacturers ceased production last year. As a result, most stores have run out of diazinon.
"We think there are a few retailers with the product on the shelf, but not much," said Laura Parsons, a team leader at EPA's Office of Pesticide Programs in Washington.
On Thursday, an EBay seller in Florida was auctioning at least 20 8-ounce spray bottles at a beginning price of $3.50 each, but the auctions stated that all sales would end Friday. A gallon of highly concentrated diazinon sold for $132.50 in an EBay auction Wednesday.
Most nurseries and other stores haven't offered diazinon for months.
"We stopped selling it since the first of the year," said Rudy Refuerzo, assistant manager at an Armstrong Garden Center in Long Beach. "We tell consumers it's been off the market because of the EPA directive."
Multipurpose chemical pesticides such as diazinon are rare because the EPA has phased out several organophosphates, which kill insects by targeting their nervous systems.
The bans came after President Clinton signed a tougher pesticide law in 1996.
Diazinon is still legal to use on about 40 crops, and California ranks among the top three states that use substantial amounts for agriculture.
EPA officials said the risks from agricultural use are considered low compared with residential use because the chemical is most dangerous from inhalation and skin contact, not from consumption of foods. Small amounts have been detected in some food and drinking water, but the levels are below that which might pose a risk to people, according to an EPA assessment.
Environmental groups, however, have criticized the EPA for not banning all uses of a pesticide with known dangers.
Unlike the pesticide DDT, which was banned in the United States 30 years ago, diazinon does not persist in the environment or build up in the food chain. Instead, it is short-lived, breaking down within hours. However, it moves through soil and readily flows into groundwater or surface water. Residential use of diazinon in the 1990s accounted for more bird kills than any other pesticide, the EPA said.
High doses can kill people or cause neurological problems such as dizziness, headache, weakness, muscle paralysis and nausea, according to the federal Agency for Toxic Substances and Disease Registry. Diazinon was derived from the same family of chemicals as the sarin nerve gas developed during World War II.
The insecticide was sold in liquid and granular form and was often marketed as a lawn treatment or ant killer under brand names such as Ortho, Spectracide and Real-Kill. Its chemical name is listed on the label under active ingredients.
If consumers choose to use it, they should wear gloves, and pets and people should be kept off the lawn or garden for several hours. Care should be taken to prevent the insecticide from washing off yards into waterways.
Consumers should not throw unwanted diazinon or other chemicals in the trash or down the drain. Instead, they should contact their city or county household hazardous waste program for free disposal. Los Angeles County residents can call (800) 238-0173 or (888) CLEAN-LA for collection locations. Orange County residents can call (714) 834-6752.