Plugging leaks in underground gas tanks

It's a classic case of the mouse that roared. Last month, tiny Rhode Island proposed what may be the nation's most stringent measures to plug leaky gasoline storage tanks: Some 6,000 underground tanks must be replaced within the next seven to eight years.

At $10,000 a shot for the required new double-walled steel tank, the proposal is not going over well.

''I don't see the reason for it. I just had brand new fiberglass tanks put in last year,'' laments Tom Salvatto, a Mobil service-station owner in Providence.

But Robert L. Bendick, director of the state's Department of Environmental Management, defends his proposal as necessary to protect drinking water. Thirty-five cases of leaking underground storage tanks have been reported in Rhode Island since 1980. Several neigborhoods have been forced to drink bottled water.

''Environmental agencies are criticized: 'Why did you let this happen?' Well, it is happening and we have a responsibility to do something now,'' Mr. Bendick says.

Of an estimated 1.7 million petroleum storage tanks buried nationwide, some 15 to 25 percent may be leaking, according to the Environmental Protection Agency (EPA). For 110 million Americans, groundwater is their sole source of drinking water. ''We believe this is potentially one of the most serious problems we're going to face in the next decade,'' says Paul Keough, deputy administrator of the New England EPA office.

There are no hard numbers yet. ''We have no idea of the scope of the problem. Maybe it's not a generic problem, maybe it's more localized,'' says Marty Halper , at the EPA's headquarters in Washington, D.C. The EPA has just completed a study of ''all the information available'' and is embarking on further studies to define the problem.

Mr. Halper considers the blanket regulations being passed or considered by states such as Rhode Island as ''overly protective, overly expensive, and not well thought out.''

''There is not enough information to write a legitimate piece of legislation, '' says Halper.

Nonetheless, there are two bills in Congress that would require registration of all underground tanks and use of standardized designs. One bill has passed in the House, the other is on the Senate floor.

The major oil companies, which own about 35 percent of the tanks, are not waiting for legislated changes. Hit by a number of multimillion-dollar lawsuits, most are spending millions to replace steel tanks with fiberglass tanks.

There is no accurate way to see if a tank, whether fiberglass or steel, is leaking, says EPA's Mr. Halper. Other experts say that if the leak is large enough it can be measured by checking the tank level frequently. Rhode Island's double-wall tank would have a sensor between the walls to warn of a leak before it reached the surrounding soil.

Robert Bendick's proposal reaches far beyond the big oil companies. At least half of the underground-tank owners are small businesses such as bakeries, soft-drink bottlers, taxi companies, and car dealers. And that is a politically sensitive constituency to regulate.

''It's OK if we're looking to the large corporations, the villians with deep pockets. But if the little guy is doing something environmentally harmful, is it OK? People are more reluctant to act because those responsible are their friends and neighbors.''

Even at the national level, ''it's a delicate political issue,'' says Donald Feliciano at the Congressional Research Service. ''The federal government is very protective of the small businessman, who also represents the greatest population of underground storage tank owners.''

But, he notes, ''the liability to both the big guys and the little guys is tremendous.''

A small leak can be a major problem. The EPA says that only one gallon of gasoline can pollute 750,000 gallons of water.

Currently, the federal hazardous-waste cleanup ''Superfund'' does not include petroleum spills or leaks. So individuals, towns, and states typically sue to recover costs of leaking tanks.

A suit is pending in Provincetown, Mass., over a leak that polluted the town's main well in 1977. State funding was given recently and cleanup will begin soon. It is expected to take another two to three years at a cost of $5 million to $7 million.

In Richmond, R.I., Exxon Corporation and Mobile Corporation each contributed water. And, $100 million civil suit is pending.

As part of his proposal, Bendick hopes to get state money to ease the impact of the tank switch on Rhode Island businesses. One suggestion by the Ocean State Service Station Retailer's Association is to use part of a gas tax already levied by the state. A meeting on the issue is set for next week.

Of his tough stand, Bendict says, ''We wanted to get people's attention. We wanted to mobilize thought on how to solve this problem.''