To: Winston H. Hickox, Secretary for Environmental Protection
From: Joan E. Denton, Ph.D., Director
Date: March 9, 1999
Subject: Adoption of a Public Health Goal for Methyl Tertiary
Butyl Ether in California drinking water
In accordance to Health and Safety Code, Section 116365 (California
Safe Drinking Water Act of 1996, SB 1307, Calderon/Sher), the Office
of Environmental Health Hazard Assessment (OEHHA) hereby adopts
a Public Health Goal (PHG) of 13 ppb (parts per billion, or micrograms
per liter) for methyl tertiary butyl ether (MTBE) in drinking water
based exclusively on public health considerations.
OEHHA has completed a technical support document which provides the basis
for the adoption of the PHG for MTBE. This document has undergone
peer review, a public workshop, and two public review and comment
periods in fulfillment of the requirements of Health and Safety
Code, Section 57003 (SB 1082). The final document incorporates changes
in response to comments and will be available on our web site.
The technical support document provides information on health effects
that may result from MTBE exposure and estimates the level of the
contaminant in drinking water that would pose no significant health
risk to individuals consuming the water on a daily basis over a
lifetime. PHGs represent non-mandatory goals based solely on public
health considerations, and are developed based on the best available
data in the scientific literature. The document provides technical
assistance to the Department of Health Services (DHS) for establishing
a primary drinking water standard (Maximum Contaminant Level, or
MCL) which also considers economic factors and technical feasibility.
It also provides relevant information useful to federal, state,
and local public health officials.
Neither the U.S. Environmental Protection Agency (U.S. EPA)
nor California DHS has established an MCL for MTBE. California has
recently adopted a Secondary MCL of 5 ppb based on taste and odor
effective January 7, 1999. The Drinking Water Advisory Level recommended
by U.S. EPA in 1997 is 20 to 40 ppb.
OEHHA appreciates this opportunity for developing the PHG for MTBE
in fulfillment of our mission in environmental and public health
Download the technical support document
for MTBE in drinking water.
Download the response to public comments
for the draft technical support document for MTBE in drinking water.
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For technical assistance or comments, please contact our Web
Last Updated March 12, 1999