Wednesday, Oct. 29, 2008

TCE exposure risks debated by analysts

While TCE is a known health hazard, experts have disagreed about how much exposure causes problems.

It also is difficult sometimes to draw direct correlations between TCE exposure and health problems because cancer and other diseases can take decades to develop. Other household goods and environmental factors also can contribute to health issues related to TCE exposure.

The risks from TCE were thought to be minimal throughout the 1990s, but the EPA issued a new risk assessment in 2001 that found the chemical to be up to 40 times more carcinogenic than previously thought.

That assessment was opposed by the Defense Department, the Energy Department and NASA, and the Bush administration sent the matter to the National Research Council for further study. The EPA withdrew its findings pending the council's study.

Lenny Siegel, an expert on TCE contamination, said one reason federal officials opposed stricter TCE standards is because it would have cost the Pentagon billions of additional dollars in cleanup costs at closed military bases.

The Pentagon has 1,400 properties contaminated with TCE. A 40-acre TCE plume at the former Myrtle Beach Air Force Base, for example, had contamination levels eight times greater than what has been found on the Horry Land Co. property.

"The world's largest TCE polluters have an inside track on setting the standards because they are the federal agencies that make the decisions," Siegel said.

The military said in 2001 that the EPA study overstated TCE's risks, but last year's report by the National Research Council disputed that.

"The evidence on carcinogenic risk and other health hazards from exposure to trichloroethylene has strengthened since 2001," the report stated.

There now is a push in Congress to adopt tougher TCE standards that would set the risk threshold at as little as one part per billion. For example, the Toxic Chemical Exposure Reduction Act of 2007 was introduced in the U.S. Senate in August.

Under the proposal, the EPA would be required to issue a new health advisory for TCE within 6 months, including revised standards for TCE in drinking water and for vapor intrusion.

"The legislation would force the adoption of new standards more quickly," Siegel said. "Right now, the health risks are tied up not just in arguments over science but arguments over politics."