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The New York state Health Department has proposed cutting the permissible amount of the gasoline additive MTBE in public water systems to help prevent people from drinking the possible carcinogen.
"There is sufficient toxicological data to raise concern over the health risks of MTBE in drinking water," the department said in explaining its new regulation.
According to a report filed yesterday by Associated Press writer Michael Virtanen, the agency proposed a limit of 0.010 milligrams of MTBE per liter (mg/L) in water supplies. Currently methyl-tertiary-butyl-ether is covered by the state limit for "unspecified organic contaminants," which is five times higher at 0.050 mg/L.
Last week the department set a 45-day public comment period on its proposal.
In long-term studies, MTBE caused lymphoma, as well as liver, testicular and kidney tumors in rats that inhaled or ingested it. Though no data is available so far on the risks to people from exposure, the Health Department said, "These animal data raise concerns about the carcinogenic potential of MTBE in humans."
Used since the 1970s to increase octane and boost the amount of oxygen in fuel, allowing it to burn cleaner, MTBE is an ether made by combining isobutylene, which is a byproduct of petroleum refining, and methanol derived from natural gas. Cleaner-burning fuel cuts air pollution.
Starting in January, New York will outlaw sale or import gasoline containing MTBE because of concerns over groundwater pollution. Congress is considering a similar ban, and petroleum companies are preparing to use corn-based ethanol as a substitute additive.
Testing of water supplies in the northeastern United States has found low levels of MTBE in about 15 percent of samples. The Health Department's analysis of 1,248 public water supplies over the past five years found one sample above the existing MTBE limit.
But sampling of private water supplies in New York found MTBE concentrations at or above the proposed lower limit in 28 percent of samples.
The regulations will apply to about 1,000 municipal water systems statewide; about 2,350 privately owned systems that meet the definition of a public system and serve residential subdivisions, mobile home parks, apartment buildings, nursing homes and private schools and colleges; and most of the nearly 6,500 "noncommunity" water systems that serve restaurants, motels and campsites.
The rule does not apply to private wells, except as guidance for the state in treating fuel spills.
The cost of cleaning up a contaminated well through installation and five-year operation of a treatment system is estimated at $10,000 per well – with a possible annual impact of $8 million to $44 million for treating thousands of private wells.
The department projected the total annual cost for municipal systems could range from $3 million to $8 million.
For privately owned systems, it said monitoring costs shouldn't rise, and spill treatment may be paid by pursuing the responsible party or by tapping the state Department of Environmental Conservation Spill Fund.
The DEC's spill response program in 1998 documented 47 public water systems and 867 private wells affected by MTBE.
On Aug. 27, Gov. George Pataki signed a new law to require the DEC to publicly report gas spills involving MTBE and cleanup efforts. The agency already reports gas spills on its Web site and plans to add MTBE information, said spokesman Matt Burns.
More than three years ago, the state Legislature passed the measure banning the sale or import of gasoline with MTBE in New York starting next Jan. 1 to reduce groundwater contamination. Connecticut and California have the same deadline, and 14 other states have similar measures but later deadlines.