

Among the Bush administration's final environmental legacies will be a decision to exempt perchlorate, a known toxin found at unsafe levels in the drinking water of millions of Americans, from federal regulation.

The ruling, proposed by the Environmental Protection Agency in October, was supposed to be formalized on Monday. That deadline passed, but the agency expects to announce its decision by the year's end, before president-elect Barack Obama takes office. It could take years to reverse.

Critics accuse the EPA of ignoring expert advice and basing their decision on an abstract model of perchlorate exposure, rather than existing human data.

"We know that breast milk is widely contaminated with perchlorate, and we know that young children are especially vulnerable. We have really good human data. So why are they putting a model front-and-center?" said Anila Jacobs at the nonprofit Environmental Working Group. "And they used a model that hasn't yet gone through the peer-review process."

The ruling is one of dozens planned for the final days of the Bush administration. Others include a relaxing of air pollution standards for aging power plants, and a reduction of the U.S. Fish and Wildlife

Service's traditional role in evaluating the impact of federal projects on endangered species.

These have received more attention than the status of perchlorate, a chemical found mostly in jet rocket fuel and detected in 35 states and

153 water public water systems. It is known to lower thyroid hormone levels in women; it poses a particular threat to pregnant women and breast-feeding children, whose long-term neurological development can be stunted by youthful hormone imbalances.

As many as 40 million Americans may now be exposed to unsafe levels of perchlorate, and the EPA's own analysis puts the number at 16

million. The most comprehensive human exposure study, which measured unexpectedly high perchlorate levels and correlated them with thyroid hormone drops, was concluded by the federal Centers for Disease

Control and Prevention in 2007.

Environmental health advocates saw the study as supporting tightened restrictions on perchlorate levels in drinking water — something the EPA had been loath to do under the Bush administration. The study was not considered in the anticipated ruling, which could effectively end federal monitoring of perchlorate in drinking water.

"If you used the human studies from the CDC, then you would be forced to regulate it, because we know there are health effects at current levels of exposure," said Jacobs.

Benjamin Blount, co-author of the CDC's study, would not comment on the EPA's decision, but said that infants — who consume, proportional to their body weight, about six times more water than adults — "are thought to have a higher dose than at any other life stage."

The EPA declined to comment on why they used a model rather than the

CDC's data in deciding that regulating perchlorate would not provide "a meaningful opportunity for health risk reduction for persons served by public water systems."

In a November letter to EPA administrator Stephen Johnson, the EPA's own Science Advisory Board questioned the model. "Its soundness will not be publicly vetted," they wrote. Only one of two peer reviews invited by the agency has been received, and that was announced only today on the EPA's website.

"The Science Advisory Board believes that more time is needed for the decision process and for scientific input," said Joan Rose, a

Michigan State University water researcher and chair of the Board's

Drinking Water Committee.

Even Michael Dourson, a researcher at the nonprofit Toxicology

Excellence for Risk Assessment project who accepts the EPA's model, doesn't understand why the EPA favored it over human studies.

"The data is on pregnant women and babies, and these studies are quite powerful," he said. "If they could spend more time to make their decision, I'd recommend looking at it."

According to EPA spokeswoman Enesta Jones, the agency expects to announce a decision "by the end of the year." There is little reason to think the ruling will change from its current form.

"This administration has been adamant about not regulating perchlorate," said Mae Wu, an attorney at the nonprofit Natural

Resources Defense Council.

If the rulings go through, Congress may still take action. California congresswomen Barbara Boxer and Hilda Solis, both Democrats, have each drafted legislation that would force the EPA to regulate perchlorate, though it could take years to go into effect.

States still have the option of regulating perchlorate on their own

— but this is not easy, said Charles DeSaillan, New Mexico's assistant attorney general for natural resources.

"We have fairly limited resources. Historically we've relied on the federal drinking water standards, and adopted those," he said. "In order for us to adopt our own, we'd have to do all the science, all of the research, hire the experts, and go through a regulatory process which would be opposed by the Department of Defense and Department of

Energy."

New Mexico is home to several prominent military testing facilities, and has the highest average perchlorate exposures in the country.

"It'd be long and difficult. Eventually we may do it. But it's easier for us to rely on the EPA. This is their job. And in the case of perchlorate, they don't seem to be doing it," said DeSaillan.

See Also:

Images: 1. Baby nursing from a bottle / pfly 2. Map of perchlorate manufacturer locations / EPA

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