The National Toxicology Program Releases Draft Report Linking Hexavalent Chromium in Drinking Water to Cancer in Animals

May 1, 2007

The National Toxicology Program recently released a draft report on its two-year studies of rodents exposed to hexavalent chromium in drinking water. These studies were undertaken because of concerns raised by a number of California legislators and regulatory offices, including the California Environmental Protection Agency, the California Department of Health Services, and the California Office of Environmental Health Hazard Assessment. The studies found that high doses of hexavalent chromium caused a statistically significant increase in certain cancers in mice and rats, and NTP’s draft concluded that the studies found “clear evidence of carcinogenic activity” in both species. The NTP Board of Scientific Counselors’ Technical Reports Review Subcommittee will review the draft report on May 16-17, 2007. Information about these meetings can be found on the National Toxicology Program website.

This new report may affect drinking water standards for hexavalent chromium around the country. California’s Office of Environmental Health Hazard Assessment (OEHHA) previously proposed a cancer-based Public Health Goal (PHG) using the limited data available at the time. Following criticism from scientific peer reviewers selected by the Regents of the University of California, it decided there was insufficient data to reliably calculate a PHG based on a cancer outcome and instead has been preparing a non-cancer based PHG. This new data from NTP may be viewed at OEHHA as justifying a cancer-based approach, which would likely result in a substantially lower PHG and could lead to a low Maximum Contaminant Level for hexavalent chromium in California. Other states, such as New Jersey (which has also closely followed these issues), and the United States Environmental Protection Agency may take similar action, especially given the new Congress’ focus on environmental issues.

The result of these developments could be significantly greater clean-up costs. Additionally, plaintiffs in current and future toxic tort cases may also attempt to improperly use these studies, which used enormous doses and do not address the critically important species differences, to support their claims related to alleged hexavalent chromium exposures. 

Gibson, Dunn & Crutcher’s Environment and Natural Resources Practice Group has particular expertise in toxic tort and cost recovery actions related to hexavalent chromium. We also handle a range of other environmental litigation and counseling matters nationwide. 

To learn more about the firm’s environmental litigation, please contact the Gibson Dunn attorney with whom you work or Raymond B. Ludwiszewski (202-955-8665, [email protected]) in Washington, D.C., Robert W. Loewen (949-451-3894, [email protected]) in Orange County, or Patrick W. Dennis, Practice Group Chair (213-229-7567, [email protected]) in Los Angeles.

© 2007 Gibson, Dunn & Crutcher LLP

The enclosed materials have been prepared for general informational purposes only and are not intended as legal advice.