Dichlorvos, or DDVP, is a household pesticide related to World War II-era nerve agents. In May the Environmental Protection Agency proposed its continued sale, despite considerable evidence suggesting it is carcinogenic and harmful to the brain and nervous system, especially in children. On several occasions, the agency has come close to banning the pesticide--used in no-pest strips as well as in agriculture--but has always backed away. Environmentalists and labor unions charge that the latest decision was the product of backroom deals with industry and political interference--just as they did 25 years ago, when the EPA first considered a ban on DDVP and other similar pesticides.

"It's been two decades, and the riskiest uses--the home uses--are still on the market," says Aaron Colangelo, an attorney with the Natural Resources Defense Council (NRDC), which has sued the EPA over the pesticide. "It's bizarre, it's unlawful and it's a complete failure of the agency to protect public health."

DDVP is an organophosphate, one of a group of pesticides developed after World War II, when researchers discovered that insects' nervous systems were more sensitive to nerve agents than the human nervous system. The idea was that small amounts of these agents would be lethal to insects and harmless to people.

Questions about their safety arose in the 1970s. The EPA considered a ban on 13 pesticides in 1981, including DDVP, but took no action. The NRDC and labor unions sued the EPA. In the settlement, the agency said it would make a decision on the chemicals' safety by 1986.

The EPA missed that deadline. In 1988 it said DDVP deserved "special review," a designation that often leads quickly to a ban. The EPA again failed to act.

In 1996 a frustrated Congress passed the Food Quality Protection Act, giving the EPA until this year to make a firm decision on the safety of the estimated 800 pesticides in use in the U.S. The EPA has acted on many of them, but it is unlikely to meet its deadline for completing the pesticide review.

In its decision in May on DDVP--now the poster child for the agency's failure--the EPA added some restrictions to household use, saying the pest strips could be placed only in garages, cupboards, attics and crawl spaces. But that is unlikely to limit human exposure, insists David E. Camann of the Southwest Research Institute in San Antonio, Tex. "It's highly volatile, so it doesn't stay where it's put," he says. "It's going to migrate quickly through the air, and people are going to breathe it."

Colangelo says EPA officials told him these restrictions had been proposed by DDVP's maker, Amvac Chemical Corporation in Newport Beach, Calif., and that the EPA had quietly negotiated the details with the company--something it is not legally allowed to do. The EPA denies that, saying it pursues "a very open and transparent process." Amvac defends the product's safety and denies it colluded with the agency. "There were no 'backroom deals' with the EPA," Amvac said in a statement.

The agency's own employees charge, however, that industry is far too involved in these decisions. In a letter written May 24 by their union leaders, they complained that their colleagues in the pesticide program "feel besieged by political pressure exerted by agency officials perceived to be too closely aligned with the pesticide industry."

In June the NRDC once again took action, filing a petition charging that the latest decision was negotiated illegally and demanding an immediate ban on DDVP. The dispute is most likely headed to court.