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Process for PHG Development and Chemicals Undergoing Evaluation

Under Health and Safety Code Section 116365, as amended by the Calderon-Sher Safe Drinking Water Act of 1996, OEHHA develops and adopts Public Health Goals (PHGs) for chemicals in drinking water. PHGs are to be based on risk assessments conducted using "most current principles, practices, and methods used by public health professionals" and certain public health criteria. OEHHA is required to develop and adopt PHGs for drinking water contaminants for which there already is a primary drinking water standard (maximum contaminant level, or MCL) as well as for any newly regulated contaminants. PHGs are solely health based; the evaluations and estimated safe levels provide information to the California Department of Health Services as to whether any changes might be appropriate in state MCLs on the basis of the most recent toxicity data and risk assessment methods.

Section 116365 provides a timetable for adopting PHGs for which MCLs already exist, requiring 25 PHGs to be adopted by January 1998, 25 additional by January 1, 1999, all remaining drinking water contaminants with existing MCLs by December 31, 1999, and adoption to be completed for the remaining PHGs by not later than January 2000.

The PHG development process is also guided by Health and Safety Code Section 57003. This statute requires that a public workshop be held whenever a hazard evaluation of a chemical will be used by another department or board in a regulatory process. Following the workshop, the agency is to revise the evaluation, as appropriate, and circulate it for public comment for a period of at least 30 days. Section 57003 further states that no delay or postponement is authorized in any case where a time period for adopting a health evaluation is established by law.

The first 27 PHGs for 26 chemicals were adopted in December 1997. These chemicals were alachlor, antimony, B(a)P (benzo[a]pyrene), chlordane, copper, cyanide, dalapon, DEHP (diethylhexylphthalate), 1,2-DCB (1,2-dichlorobenzene), 1,4-DCB (1,4-dichlorobenzene), 2,4-D (2,4-dichlorophenoxyacetic acid), dinoseb, endothall, ethylbenzene, fluoride, glyphosate, lead, nitrate, nitrite, oxamyl, PCP (pentachlorophenol), picloram, trichlorofluoromethane (Freon 11), trichlorotrifluoroethane (Freon 113), uranium and xylenes.

The documents are available on the OEHHA Web site at www.oehha.ca.gov

The overall process used for the development of PHGs includes the following steps:

  1. selection of chemical contaminants to evaluate,
  2. review and evaluation of relevant information,
  3. preparation of the draft risk assessment documents to describe the proposed PHGs,
  4. announcement of a public workshop in the California Regulatory Notice Register and on the OEHHA Web site,
  5. making the draft documents available for public review, including posting them on the OEHHA Web site,
  6. convening a public workshop for discussing the proposed PHGs
  7. revision of the draft documents based on consideration of the comments received,
  8. providing the revised draft documents for public review for a 30-day period,
  9. revision of the documents in response to review of the comments,
  10. adoption of the final documents, and response to general comments received, and
  11. posting of the final documents.

Currently OEHHA is at different stages of reviewing the following chemicals: atrazine, bentazon, benzene, cadmium, carbon tetrachloride (CCl4), chromium (total), DBCP (1,2-dibromo-3-chloropropane), 1,2-DCA (1,2-dichloroethane, ethylene chloride,), 1,1-DCE (1,1-dichloroethylene, ), DCM (dichloromethane, methylene chloride), 1,2-DCP (1,2-dichloropropane, propylene chloride), 1,3-DCP (1,3-dichloropropene), endrin, heptachlor, heptachlor epoxide, lindane (g -hexachlorocyclohexane, g -HCH), HEX (hexachlorocyclopentadiene), mercury, methoxychlor, MTBE (methyl tert- butyl ether), PCBs (polychlorinated biphenyls), PCE (tetrachloroethylene, perchloroethylene), simazine, thallium, 1,2,4-TCB (1,2,4-trichlorobenzene), TCE (trichloroethylene), and toluene. OEHHA plans to make the draft documents supporting the proposed PHGs for the selected chemicals available for public review in September 1998 ; the workshop is planned for October 1998; and adoption is anticipated in December 1998. The final number of documents going through the public review, workshop and adoption during 1998 has yet to be determined.

MTBE (methyl tertiary butyl ether) is on a separate time schedule as a newly regulated chemical. After the first comment period and public workshop held on May 15, 1998, the revised document was posted on the OEHHA Web site for a 30-day comment period which ended July 13, 1998. Document revision in response to public comments is currently underway, and adoption is expected in the summer of 1998.

For further information, please contact OEHHA at:

Cal/EPA-OEHHA-PETB
Water Toxicology
P.O. Box 4010
Sacramento, CA 95812-4010
(916) 324-7572