Council warns of strong ties between TCE, kidney cancer

Washington-Trichloroethylene (TCE) is a chlorinated hydrocarbon once commonly used as a degreasing agent in industrial settings. The nonflammable, colorless fluid may also be found as an ingredient in adhesives, paint removers, typewriter correction fluids, and spot removers. Although a clear-cut link between TCE and cancer has yet to be established, the chemical is the subject of a recent report calling for research on how it causes cancer and other adverse health effects.

Studies, including those conducted in humans, support that TCE is a potential cause of kidney cancer, according to the report.

In 2001, the U.S. Environmental Protection Agency issued a draft risk assessment of TCE that said the solvent's potential to cause cancer might be up to 40 times greater than had been previously thought. EPA's assessment of risks posed by the chemical was immediately criticized by industry and by the U.S. Department of Defense, the Department of Energy, and the National Aeronautics and Space Administration. These government agencies had used or were using the compound and had harbored an estimated 1,400 waste sites contaminated by the chemical.

Stronger evidence

To resolve the issue, the Bush administration turned to the National Academy of Sciences with a request that its National Research Council (NRC) provide advice on the major issues related to assessing the health risks associated with exposure to TCE. The final NRC report, issued in July 2006, stated: "The committee found that the evidence on carcinogenic risk and other health hazards from trichloroethylene has strengthened since 2001." It also rejected industry's position that TCE at low levels did not pose a health risk.

"Animal research studies and human population studies suggest that TCE exposure may also be associated with other health effects, such as reproductive and developmental problems, impaired neurological function, and autoimmune disease," NRC said in a statement announcing the release of the report.

Rogene Henderson, PhD, senior scientist emeritis at the Lovelace Research Institute, Albuquerque, NM, and chairperson of the NRC committee that produced the report, told Urology Times that the NRC report should not be construed as a new health risk assessment of the link between exposure to TCE and the development of kidney cancer or kidney disease.

"I can't emphasize enough that we did not do a risk assessment. We told the EPA that they already have enough information to do a risk assessment, and that they should proceed with one," she said.

Following promulgation of the risk assessment, EPA would issue regulations.

"The take-home message is that people should know what solvents they are working with and what risks are associated with them," said Mary Davis, PhD, a professor in the department of physiology and pharmacology at the West Virginia University Health Sciences Center, Morgantown, and a kidney disease specialist who served on the NRC panel.

Dr. Davis added that urologists who are pursuing a diagnosis of kidney cancer or kidney disease may wish to ask the patient about his or her exposure to solvents used at work and in hobbies.

The path is now open for EPA to reassess the risks posed by TCE and to issue regulations that would govern the chemical's use and direct the cleanup of waste sites. A portion of the council's report describes a more accurate model for evaluating data and establishing risks for cancers and other diseases. The model does not require the acquisition of new data.

When the EPA will start down the path delineated by the NRC is not yet known.