Panel OKs testing pollutants on volunteers

By Shankar Vedantam
The Washington Post

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While the Environmental Protection Agency (EPA) refused to consider human trials during the Clinton administration, the Bush administration reopened the possibility of using the tests. Many scientists and ethicists have argued that such research never is justified.

The pesticide industry has vehemently supported such tests for years, arguing that current regulatory limits on environmental exposure to toxic chemicals are overly cautious. Manufacturers of pesticides and companies that generate pollutants say human studies will demonstrate that higher levels of toxins in the air and water are not harmful.

Currently, EPA regulators first determine what dose is toxic to animals. Regulators divide that dose by 10, because humans may react more sensitively than animals — called the "interspecies safety factor." Because some people are more sensitive than others, regulators lower the potentially toxic dose by another factor of 10. Finally, to protect children and fetuses, a third safety factor of as much as 10 is introduced. These safety factors can reduce human exposure limits to toxins to one-thousandth the dose that harms animals.

While volunteers would derive no benefit and some might incur transient harm from tests on human subjects, the panel of experts said this would be outweighed by societal benefits. Besides helping regulators set accurate benchmarks for environmental dangers, such trials also might address, for example, how much insecticide can be used safely to fight a malaria outbreak.

Yesterday's decision will allow the EPA to devise a final rule over the next several months, an agency spokesman said. Both the pesticide industry and environmental groups said they expect the agency to accept the recommendation of the panel, which also would allow the EPA to evaluate human studies of pesticides that had been conducted previously and give the industry an incentive to conduct new trials.

The panelists called for a rigorous safety and ethics system to evaluate and approve such trials, much like the system used by the Food and Drug Administration to evaluate drug trials conducted by the pharmaceutical industry.

While there was no "foolproof mechanism" to eliminate all risk of patient harm, the joint chairman of the panel, James Childress, an ethics professor at the University of Virginia, said that the risk for volunteers generally would be "exceedingly low."

Environmental groups acknowledged that the panel had tried to institute safeguards but feared that trials still would cause harm.

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