Under proposed changes to federal research ethics standards, the Environmental Protection Agency will no longer accept studies that use people as guinea pigs in chemical tests.

In 2006, under chemical-industry pressure, and over arguments that the studies were scientifically and ethically bankrupt, the EPA declared such data acceptable. On June 16, the EPA reversed its decision.

"What we were really concerned about is toxicity studies, where they're trying to do a study on humans to determine the dose response of a chemical," said Jennifer Sass, a senior scientist at the Natural Resources Defense Council, a liberal nonprofit. "If the EPA stops accepting them, there's no motivation for companies to conduct them."

Almost every standard code of medical ethics – including the Nuremberg Code, written in response to Nazi doctors' nightmare studies – forbid human tests of drugs or chemicals that may cause harm, but can provide no direct benefit.

The chemical industry, however, has long argued that the EPA should accept data from tests in which healthy volunteers are paid for exposing themselves to pesticides and other known toxins. The industry says such data provide a more accurate picture of chemical effects than animal studies.

Critics say the resulting science is worthless, with companies running tests on small, non-representative groups of people, such as healthy young men, in order to create a false impression of safety. More importantly, the tests put people at potentially grave physical risk, with no benefit but a cash payment.

"These pesticides are intentionally designed to be toxic. Their whole purpose is to kill insects and invasive plants," wrote senator Barbara Boxer (D-CA) and representative Henry Waxman (D-CA) in a 2005 report (.pdf) on the industry's tests. "Yet in the experiments, test subjects swallowed insecticide tablets, sat in chambers with pesticide vapors, had pesticides applied to their skin, had pesticides shot into their eyes and noses, and were even exposed in their homes for six months at a time."

Continued Waxman and Boxer: "The subjects were not told of the dangers of exposure to the pesticides. Sometimes, they weren't even told the substances being tested were pesticides. They were misled into believing that they were participating in 'drug' trials, not pesticide experiments."

Nevertheless, the Bush-era EPA – led by Stephen Johnson, a former tobacco-industry scientist – said they'd accept data from those studies. The NRDC, along with liberal nonprofits Pesticide Action Network and Earthjustice, filed suit in federal court.

Proposed rule changes announced by the EPA on June 16are the result of negotiations that accompanied the legal battle. They extend protections from the Common Rule (a widely accepted set of medical ethics that forbid intentional-dosing studies that have no benefit) to all people involved in EPA-accepted studies. Extra protections are given to children and pregnant women.

"EPA expects its tougher new rules will decrease the number of systemic intentional dosing toxicity studies conducted for pesticides," reads the EPA website. "We expect the number of systemic toxicity studies to drop to as few as zero or one per year."

The rules will be opened to public comment in January of 2011, and will need court approval to finally become law.

The American Chemistry Council, the major chemical industry trade group and an advocate of expanded human testing, did not respond to requests for comment.

According to Sass, Some data on human exposures to chemicals may still be used. Reports from accidental poisonings, worker exposures and other unintentional dosing exist, and "EPA could incorporate a lot of that unfortunate, real-world data," she said.

"Pesticide companies should not be allowed to take advantage of vulnerable populations by enticing people to serve as human laboratory rats," said Pesticide Action Network senior scientist Margaret Reeves in a press release.

Image: Flickr/Michelle Tribe

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Brandon Keim's Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.