WASHINGTON, D.C.--For the past 5 years, the Environmental Protection Agency (EPA) has been struggling with whether to include controversial studies in which human volunteers ingest pesticides as part of its safety reviews of the compounds. Last week, a new National Academy of Sciences (NAS) panel heard from both advocates and opponents of these so-called dosing experiments. Their vehement debate underlines the difficulty the panel faces in trying to untangle complex scientific and ethical questions.
The trigger for the debate was a 1996 law that mandated that EPA reduce acceptable levels of pesticides in foods to protect children. Until then, EPA had set pesticide limits mainly using animal data. Faced with tighter limits, pesticide companies hoped to use human studies to avoid a safety factor built in to account for possible higher sensitivity in people. Companies have since submitted about two dozen human toxicity studies to EPA in which volunteers mostly in Scotland and the United States were paid up to $1000 (see table).
After an environmental group criticized the studies as unethical, EPA officials shelved them until an advisory committee weighed in (Science, 1 January 1999, p. 18). That committee issued a report in 2000 saying some human tests were acceptable--but not experiments done solely to find what dose causes effects. EPA under the Bush Administration indicated that it would consider the dosing tests, but under heavy criticism it decided in late 2001 to hold off and requested the academy study.
Much of the ethics debate hinges on whether society is likely to benefit from the tests. Pesticide dosing tests are unethical because they only benefit industry, asserted Richard Giles of the Environmental Working Group, an advocacy group in Washington, D.C. But Ray McAllister of CropLife America, an industry group, argued that dosing tests of pesticides are in fact no different from phase I clinical trials of drugs, which test toxicity and don't directly benefit the subjects.
The overarching problem with all human data used by EPA, said Lynn Goldman, a pediatrician at Johns Hopkins University and a former EPA official, is that unlike the Food and Drug Administration, EPA has no protocols for human studies and lacks a stringent policy for ethics reviews of human data. The agency "needs strong and enforceable standards," she says, an issue the panel will likely consider.