Cleanup of Underground Gas Tank Leaks Curtailed


After a billion dollars has been spent in California removing contamination left by leaking underground gas tanks, a new study minimizing the dangers has prompted the Wilson administration to put the brakes on the costly cleanup program.

The report, which has the backing of the U.S. Environmental Protection Agency and some funding from the oil industry, concluded that natural processes in the ground remove most of the toxic ingredients left by underground petroleum leaks.

Three-quarters of the state’s 28,000 contaminated sites have not been cleaned up, and state officials had estimated that it would cost another $3 billion to get the job done. The state has been paying for the cleanups through a special levy on the owners of oil tanks. That tax was expected to raise only about 50% of the money needed to finish the job.


Under the new policy, however, the majority of the remaining sites probably won’t be cleaned up, except for removing the leaking tanks, say officials of the California Water Resources Control Board.

“This represents a major departure from the way we have been doing things,” said James Giannopoulos, manager of the water board’s underground tank program.

The board has advised its nine regional offices to halt cleanup operations at sites more than 250 feet from drinking water wells. The advisory does not recommend outright abandonment of such sites. They should be monitored, it said, to make sure that the fuel leaks do not eventually imperil water sources.

Environmentalists, including officials of the Sierra Club, have accused the Wilson administration of acting irresponsibly in a state in which 50% of the population depends on ground water for domestic supplies.

“This could shut down treatment of 80% to 90% of all sites with virtually no investigation of many of them,” said Bonnie Holmes, the Sierra Club’s state legislative director.

Some of the regional water officials responsible for the cleanups argue that the state is moving too fast, acting on the basis of a narrowly focused study that looked at contaminants in just one of several types.


“It will trigger demands that we close sites before we have sufficient information about a lot of them,” said Gordon Boggs, who heads the Central Valley’s regional water quality control board office. Boggs said 1,000 contaminated locations in his region have yet to be investigated.

On the other hand, Patricia Eklund, chief of underground storage tank regulation for the EPA’s western region, applauded the state’s reaction to the study.

“They are going to focus their efforts on the high-priority sites, and that’s as it should be,” Eklund said.

The yearlong study prompting the state’s policy shift was conducted by the Lawrence Livermore National Laboratory and largely paid for with a $300,000 grant from the EPA. The Shell Oil Co. contributed about $30,000, according to Walt Petit, executive director of the water board.

The study takes direct aim at the assumption driving the expensive, decade-long cleanup campaign--that benzene, a cancer-causing component of petroleum, threatens the state’s drinking water supply.

“Fuel hydrocarbons have limited impacts on human health, the environment or California’s ground-water resources,” the study concluded. “The costs of cleaning up FHCs are often inappropriate when compared to the magnitude of the impact on ground-water resources.”


The study, based on a review of 1,500 contaminated sites, concluded that in most cases subsurface microorganisms devour benzene and other toxins before they can pollute ground-water sources.

“The real point here is that in many cases natural processes degrade fuel hydrocarbons at approximately the same rate as technology,” said David Rice, an environmental scientist at Lawrence Livermore who coauthored the study.

Where ground water has been affected, the study says, “well construction standards” have protected all but a tiny fraction of the state’s drinking water.

By law, California’s drinking water must not contain more than one part per billion of benzene. The state standard is five times as strict as the federal limit, Rice said.

The study determined that “the total potential volume of ground water impacted greater than one part per billion benzene was estimated to be 0.0005% of California’s total ground-water basin storage capacity.”

The report did not conclude that treatment is never necessary.

It found that of 12,151 wells tested, 48 had measurable benzene concentrations. “Most of the affected wells are shallow private domestic wells in close proximity to the (contamination) release sites.”


But Rice conceded that the study had its limits--focusing on the interaction of hydrocarbons with alluvial soil, the kind found under the state’s large metropolitan areas where most gas stations and fuel tanks are located.

He said researchers did not look at what happens to the contaminants in sand and gravel or in fractured bedrock.

The state’s decision to scale down cleanup operations represents a victory for a small association of underground tank owners that had been quietly lobbying against the previous policy.

“We have been urging the water resources board to subject their policies to scientific review, and they finally did,” said Don Zedrick of the Santa Rosa-based Environmental Resources Council.

Even critics of the new policy concede that a lot of money was wasted on dubious cleanup strategies over the years.

“I think what California is doing [now] is a bit drastic,” said Paul Kostecki, an expert on contaminated soils and ground water at the University of Massachusetts School of Public Health. “On the other hand, there was bound to be a reaction. There was so much money flowing into remediation of petroleum contamination, and not enough attention being paid to the results.”