After the federal government ordered gas stations nationwide to replace underground tanks that were leaking a possible carcinogen into the ground water, state officials now find many of the new tanks also leak.
Environmentalists say the newly discovered leaks bolster their arguments that Gov. Gray Davis should not delay phasing out the use of the gasoline additive MTBE. Davis has been considering putting off the ban, which is supposed to take effect Dec. 31.
Preliminary results of a state study found that two-thirds of the upgraded tanks and pipes tested in Yolo and Sacramento counties are leaking MTBE.
In Orange, Riverside and San Bernardino counties, water officials found that of 60 new double-sided tanks they monitored, a third are still leaking gasoline. In addition, some built-in sensors supposed to warn them about leakage aren't working.
In the Silicon Valley, at least 40% of tested new tanks are releasing MTBE. At one station in San Jose, vapor leakage resulted in 2,000 pounds of MTBE contaminating soil and ground water.
"MTBE is a very significant threat to the ground water, not only in our county but across the state," said Jim Crowley, a specialist on the tanks who works for the Santa Clara Valley Water District. "The underground storage-tank systems don't appear to be able to contain MTBE."
Leakage Problem Is Widespread in State
The U.S. Environmental Protection Agency has heard of similar reports from other states, including Florida and South Carolina, said Sammy Ng, deputy director of the EPA's office of underground storage tanks. But the agency is watching California closely because the problem has been found to be so widespread in the state.
MTBE, or methyl tertiary butyl ether, was first added to gasoline more than two decades ago to reduce air pollution, and its use became widespread in the early 1990s. It initially appeared to be a silver bullet--a cheap additive that makes gas burn cleaner without harmful side effects.
Further study, however, found that MTBE is a suspected carcinogen that spreads quickly through the soil and ground water and that even in small amounts can make drinking water smell like turpentine. To stem the seepage, oil companies replaced single-walled tanks and pipes with double-walled equipment and added sensors. By 1998, under federal order, nearly all of the tanks had been replaced.
"That was supposed to cure the problem," said Ken Williams, chief of the underground storage-tank section at the Santa Ana Regional Water Quality Control Board, which enforces clean-water laws in parts of Orange, Riverside and San Bernardino counties.
He and other water experts don't know exactly how the gasoline is still escaping. But growing contamination levels in the soil around the tanks indicate it is indeed escaping.
Ng believes the culprits are the vents and pipes that connect the tanks to the gas pumps, rather than the tanks themselves. "There's a lot of piping, a lot of joints. Any time the earth moves, you may have cracks and leaks," he said.
Carolin Keith, spokeswoman for Exxon Mobil Corp., said this is the first she has heard that upgraded tanks or pipes are leaking. "As a matter of course, any soil or ground-water contamination that results from a leak in our equipment, we are both obligated and committed to cleaning up," she said.
MTBE contamination in soil and water nationwide is going to cost at least $29 billion to clean up, according to a study commissioned by Santa Monica and several other cities. And new contamination sites continue to be discovered. In January, officials announced that a plume of tainted ground water has moved close to a well that produces drinking water for 17,000 homes in Rialto, Fontana, Colton and Bloomington.
Officials believe the problem is far more widespread than reports indicate. Many gas station owners do not realize their tanks are leaking, and one common testing method might allow the MTBE to decompose before it can be analyzed.
Environmentalists say this is exactly why Davis must not delay the planned phaseout of MTBE.
Davis Concerned About Gas Shortages, Prices
In 1999, Davis declared the gasoline additive a threat to the environment and ordered that its use in gasoline be phased out of California by this coming December. But last month, he announced he may delay the phaseout because it could create a gasoline shortage or drive up prices. A final decision is expected in early April.
Bill Rukeyser, deputy secretary of Cal-EPA, a state environmental agency, said Davis will consider the environmental ramifications as well as the economic consequences when making his final decision.
He said the number of leaking tanks has decreased in recent years and the equipment, though imperfect, is much improved.
He reiterated, though, that the Davis administration is not backing off from eliminating MTBE use.