Final Technical Support Document on Public Health Goals for: Chlorobenzene, Endothall, Hexachlorocyclopentadiene, Silvex, and Trichlorofluoromethane in Drinking Water

The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency announces the publication of updated Public Health Goals (PHGs) for chlorobenzene, endothall, hexachlorocyclopentadiene, silvex, and trichlorofluoromethane in drinking water. OEHHA is also announcing the availability of the final technical support document for these PHGs.

The updated PHGs are 70 parts per billion (ppb) for chlorobenzene, 94 ppb for endothall, 2 ppb for hexachlorocyclopentadiene, 3 ppb for silvex, and 1,300 ppb for trichlorofluoromethane, all based on non-cancer effects. The updates consider recent toxicological literature and incorporate updated water consumption rates, and where appropriate, updates in risk assessment methodology and provisions to account for the most sensitive members of the population.

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 19961 requires OEHHA to develop PHGs based exclusively on public health considerations.2 PHGs published by OEHHA are considered by the California Department of Public Health in setting drinking water standards (Maximum Contaminant Levels, or MCLs).3

Draft documents have gone through a public workshop and two public comment periods. The first public review draft PHG document was released on November 1, 2013 and a public workshop was held on December 16, 2013. The second draft PHG document was released for public review on March 7, 2014. OEHHA did not receive any public comments on the draft documents.

If you would like to receive further information on this announcement or have questions, please contact Ms. Hermelinda Jimenez at or (510) 622-3170.

1Codified at Health and Safety Code, section 116270 et. seq.

2Health and Safety Code section 116365(c)

3Health and Safety Code section 116365(a) and (b)