Announcement of Second Public Comment Period for the Draft Public Health Goal for Trihalomethanes (THMs) In Drinking Water

The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency is announcing the availability of the draft technical support document for a proposed Public Health Goal (PHG) for trihalomethanes (THMs) in drinking water. The draft document on THMs has been revised since the first posting to provide a proposed PHG of 0.8 parts per billion for the combined chemicals (chloroform, bromodichloromethane, chlorodibromomethane, and bromoform), rather than separate values for the individual disinfection byproducts. The draft document is posted on the OEHHA web site ( OEHHA is soliciting comments on the draft report during a 30-day comment period. The Office previously offered a 45-day public comment period and held a public workshop on these chemicals on August 7, 2009.

This 30-day public comment period is the second and final request for public input. OEHHA will evaluate all the comments received and revise the document as appropriate. Written comments must be received at the OEHHA address below by 5:00 p.m. on October 11, 2010 to be considered for the final revision of the document. The final document will be posted on the OEHHA web site along with responses to the major comments received during the public review and scientific comment periods. OEHHA follows the requirements set forth in Health and Safety Code Sections 57003(a) and 116365 for conducting the workshop and receiving public input.

The PHG technical support documents provide information on the health effects of contaminants in drinking water. The PHG is a level of drinking water contaminant at which adverse health effects are not expected to occur from a lifetime of exposure. The California Safe Drinking Water Act of 1996 requires OEHHA to develop PHGs based exclusively on public health considerations. PHGs published by OEHHA are considered by the California Department of Public Health in setting drinking water standards (Maximum Contaminant Levels, or MCLs).

If you would like to receive further information on this announcement or have questions, please contact OEHHA at (510) 622-3170 or the address below.

Hermelinda Jimenez (
Pesticide and Environmental Toxicology Branch
Office of Environmental Health Hazard Assessment
California Environmental Protection Agency
1515 Clay St., 16th floor
Oakland, California 94612
Attention: PHG Project