Various possible causes have been suggested, including one of her aircraft crashing onto the flight deck and igniting petrol fumes from leaking tanks.

Within EPA, the source water protection program is working with the underground storage tank program to address potential threats to ground water posed by leaking tanks.

In 1993, a cleanup ordered by the Department of Environmental Conservation removed contaminated soil as well as hazardous wastes from leaking underground tanks.

But leaking tanks are a nationwide problem.

That money can only be used to clean up spills, not to find and close leaking tanks or enforce the current tank-upgrade regulations, E.P.A. officials said.

It is believed to have come from leaking tanks at a local Exxon Mobil gas station.

Furthermore, leaking sewage pipes and septic tanks pollute the drinking water network.

The lower standard is already being enforced by the state for cleanups of leaking underground tanks and other spills.

East Hampton is far from being the only municipality threatened by leaking underground tanks of home heating oil.

Fertilizers, waste disposal wells and leaking underground tanks all can contribute substantially.