Human pesticide experimentation.

Toxicological studies in which the "the test animals are people" have recently been conducted by several major pesticide manufacturers, according to a new report. The Environmental Working Group (EWG), a research and advocacy organization based in Washington, D.C., says that most of the recent human pesticide experiments have been performed in England and Scotland--even though the pesticides may be made by firms headquartered elsewhere.

The EWG cites three 1997 experiments in England--conducted for Amvac Chemical Corp. in City of Commerce, Calif., in which volunteers drank small amounts of dichlorvos, a neurotoxic insecticide, mixed into corn oil. In 1992, the French firm Rhone-Poulenc paid volunteers in Scotland to drink orange juice that had been spiked with the insecticide aldicarb.

In both sets of tests, EWG reports, some subjects experienced adverse symptoms and showed evidence of toxicity--a suppression in the activity of cholinesterase, an enzyme crucial to nerve signaling. The group notes that the U.S. Environmental Protection Agency has confirmed that additional human toxicology studies are under way overseas.

Manufacturers have used data from such tests to argue--successfully--that U.S. regulatory limits for specific pesticide residues in foods, derived from animal data, are set too high.

Responding to the EWG report, EPA notes that it "is deeply concerned that some pesticide manufacturers seem to be engaging in health-effects studies on human subjects" as a way to avoid the agency employing a safety factor for applying results of animal tests to people.

While U.S. law would likely prohibit the type of studies reported to be occurring overseas, it has not prohibited use of data resulting from them. That may change, the EPA statement says, pointing out that "protection of public health from adverse effects of pesticides can be achieved through reliance on animal testing and use of the highest ethical standards."