Oil Pool Under N.Y. Streets to Be Cleaned Up : Environment: Forty years of seepage have created a 17-million-gallon plume. Mobil will spend millions to remove it.

Mobil Oil Corp. has agreed to clean up a more than four-decade-long seepage that has left about 17 million gallons of oil--6 million more than flowed from the Exxon Valdez--under the streets of New York City.

The pool is the result of cumulative oozing from a collection of storage tanks and pipelines alongside a creek in Brooklyn’s Greenpoint section, a heavily industrialized neighborhood within sight of the skyscrapers of Manhattan.

No one knows precisely how much oil is beneath the surface, and Mobil, which has agreed to spend millions on the cleanup, plans to drill wells to determine how far the pool extends.

“You drill monitoring wells to determine where the plume is; and, once you have done that, you put in recovery wells to pump the product out of the ground,” Mark Cohen, a Mobil spokesman, said Tuesday in explaining the technology.

“It is every conceivable kind of petroleum product,” Cohen said, adding that Mobil hopes that other oil companies with facilities in the area will share the cost of the cleanup.

Thomas C. Jorling, commissioner of New York state’s Department of Environmental Conservation, said it would take at least a decade to remove all the oil.

Jorling said the 17-million-gallon estimate was produced by engineering analysis in the early 1980s and, since then, has been buttressed by estimates of oil lost from facilities in the area.

“If anything, the actual amount is likely to be higher,” Jorling said. “ . . . Seventeen or so million gallons of petroleum is a very serious spill.”

The commissioner said that the leaks had contaminated Newtown Creek in the Greenpoint area and had spilled oil under the streets. He said negotiations between his agency and Mobil took place on an intermittent basis for a considerable time and had intensified in recent months before a consent decree was signed on June 18 in which the company agreed to undertake the cleanup.

In February, New York state fined Mobil the maximum penalty of $500,000 for failing to make immediate notifications after a spill of 50,000 gallons of kerosene from one of its tanks in Greenpoint.

“I think they realized they and their industry were getting a reputation of being sloppy actors in the management of oil, and they had to take steps to improve the standards of care,” Jorling said.

“(The spills) indicate over the past several decades how profitable the oil industry has been,” the commissioner added. “They can lose 17 million gallons of petroleum and not miss it.”

Cohen said that the underground oil pool may be the result of spills dating back more than 100 years by over a dozen companies. State officials estimate that the leaks began in the 1940s. But, whatever the date, the cleanup is expected to be massive.

Some residents and workers in Greenpoint said they had been aware of the leaks for years. In the neighborhood, signs of Greenpoint’s oil heritage are clear. Petroleum tanks dominate much of the shoreline of Newtown Creek, which flows into the East River opposite Manhattan.

“(The spill is) kind of common knowledge in the neighborhood,” Nick Ditommaso, 32, said as he sat in the small office of the service station he owns. “Sometimes, you can smell it (the oil) when they are digging . . . . There have been no explosions yet.”

“Thank God we haven’t had a fire yet,” added Pablo Antonetty, 43, a worker in the filling station.

Department of Environmental Conservation officials said that most of the volatile compounds had evaporated because the oil was so old and that the threat of an explosion is low. But the oil has caused other problems. On three occasions, it has spilled into a sewage treatment plant in Greenpoint, forcing the facility to close temporarily.

In comparison to the Greenpoint pool’s 17 million gallons, the Exxon Valdez spilled 11 million gallons of crude when it ran aground on Bligh Reef off the coast of Alaska on March 24, 1989, in the worst tanker spill in U.S. waters.