The U.S. Environmental Protection Agency has issued an advisory to drinking water suppliers regarding methyl tertiary butyl ether (MTBE).
It said the advisory would provide public health protection if MTBE were detected in drinking water, as it has been in California.
In general, EPA advised water suppliers to ensure that MTBE levels do not exceed 20-40 mcg/l. (20-40 ppb), a level at which the chemical is detectable by taste or smell.
EPA said, "Recent air quality data indicate that the benefits of reducing air emissions from the use of MTBE in gasoline far exceed any known risks from the substance. EPA, other federal agencies, and private entities will continue further research on MTBE and its public health and environmental effects."
The EPA advisory noted, "The concentrations in the range of 20-40 ppb are about 20,000-100,000-or more-times lower than the range of exposure levels in which cancer and non-cancer effects were observed in rodent tests."
OFA view
The Oxygenated Fuels Association said, "Americans have a right to expect that the quality of their drinking water will not be adversely affected by unpleasant odors and taste."Fred Craft, OFA executive director, said a 40 ppb level equates to 2 or 3 tablespoons of MTBE in 150,000 gal of water, about the capacity of a half-dozen, in-ground swimming pools.
Craft noted the EPA advisory does not set a specific, health-based exposure recommendation for human consumption but sets only a sensory range.
"We are pleased that EPA believes that there would not be health concerns in the 20-40 ppb range established by this aesthetic recommendation."
Craft said the detection of MTBE in drinking water has been limited and isolated. MTBE is the principal oxygenate used in reformulated gasoline. That program, which accounts for about 30% of the gasoline used nationwide, covers 32 areas in 18 states.
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