The Agency for Toxic Substances and Disease Registry (ATSDR), a public health agency of the U.S. Department of Health and Human Services, announced today the availability of the final version of its public health assessment of the Pacific Gas and Electric site in Hinkley, California. Chromium from this facility contaminated local groundwater, causing concern about potential health problems.

ATSDR prepared the public health assessment through a cooperative agreement with the California Department of Health Services. The public health assessment presents the available information regarding exposure to hexavalent chromium in Hinkley and evaluates whether past, present or future exposures could harm people in the area. The report concludes that in the past, residents were exposed to levels of hexavalent chromium above current drinking water standards that might result in potential health risks.

There is disagreement within the scientific community as to whether hexavalent chromium causes cancer when ingested, and if so, at what dose. ATSDR takes a conservative approach in its assessment, basing conclusions on the most stringent standards available. Therefore, the report uses guidelines proposed by the state of California's Office of Environmental Health Hazard Assessment, which consider hexavalent chromium to be a carcinogen by ingestion.

The public health assessment concludes that estimated exposures may have been high enough in the past to cause a theoretical increase in the risk of developing cancer. Such exposures would not have been high enough to cause non-cancer health problems. The public health assessment also concludes that it is highly unlikely that there are any current or future risks from exposure to hexavalent chromium in Hinkley. However, the document does recommend that, in order to assure public safety, additional air and water sampling be conducted by the appropriate regulatory agencies.

ATSDR has already distributed copies of the report to community members in Hinkley. In addition, the health assessment is at the following repositories:

Comments received during the public comment period have been logged and are now part of the administrative record for the health assessment. Comments (without indication of who made them) and responses have been included in an appendix to the final document.

Community members seeking information on the procedures or the content of this public health assessment, or who would like to obtain a copy, should contact ATSDR Senior Regional Representative Bill Nelson at (415) 744-2194 in San Francisco.

For more information about the health effects of chromium, check the ATSDR Web site at http://www.atsdr.cdc.gov. Click on ToxFAQs and go to the fact sheet for chromium.