29 October 2003
Health threat of rocket fuel debated
EPA says levels are dangerous and the Pentagon disagrees
By Jennifer 8. Lee


Government scientists, speaking before a review panel, have presented sharply discordant views of the health threats posed by a chemical ingredient widely used in rocket fuel.

The ingredient, ammonium perchlorate, can leach into the water supply and has caused concern in Western states such as California.

Experts from the Environmental Protection Agency told the panel, convened by the National Academy of Sciences, that the levels of perchlorate allowed under current safety guidelines could cause thyroid problems in people, particularly in fetuses. They argued that safety levels for the chemical should be set at concentrations more than a hundred times lower than those being advocated by the Department of Defense.

Scientists from the Defense Department, NASA and the military industry countered that the environmental agency's analysis was flawed and overly cautious.

"Excess precaution for its own sake will have serious adverse effects on the national security mission of the Department of Defense," said Col. Dan Rogers, the chief of the environmental law and litigation division at the Pentagon.

"We have reviewed the EPA risk assessment," Rogers said, "and we think the document is biased, unrealistic and scientifically imbalanced."

The debate is the latest twist in a six-year struggle between environmental agencies and the Pentagon, which could potentially be responsible for paying billions of dollars in cleanup costs.

Perchlorate, a component of fuels for solid rockets such as the large boosters on the space shuttle, first became a concern in 1997, when technologies became sophisticated enough to detect the chemical at extremely low levels. The EPA set in motion a process of setting safety levels for perchlorate. Despite criticism from the Pentagon, EPA scientists have been steadfast in their recommendations, and the scientific debate was referred to the National Academy of Sciences last spring for review.

The EPA has recommended that levels of perchlorate be restricted to concentrations as low as one part per billion, but the agency's current guidelines specify concentrations of 4 to 18 parts per billion. The California Environmental Protection Agency, which has conducted an independent risk assessment, has made similar recommendations. By contrast, the Pentagon has urged that the safety levels be set at 200 parts per billion, higher than the levels of ground contamination already found.

Perchlorate contamination has been an issue for some time in the West, particularly in California and Nevada. Over 300 municipal and local wells have been closed in California alone, and Native American tribes that draw water from the lower Colorado River are contemplating lawsuits against companies to force them to clean the water. Of the 45 states where the Pentagon uses perchlorate, 25 have confirmed cases of perchlorate contamination.

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