In by far the largest incident, an Exxon pipeline poured 567,000 gallons of oil into the Arthur Kill on Jan. 1.

The cleanup of more than 500,000 gallons of heating oil pumped through a leaky Exxon pipeline into the Arthur Kill has begun to wind down, state and Coast Guard officials said yesterday.

It follows several other big spills this year in the New York metropolitan region, including one of 567,000 gallons that leaked from an underwater Exxon pipeline into the Arthur Kill on Jan. 1 and 2.

But after the big leak from the Exxon pipeline last January soiled many wetlands, concern rose about what would happen this year to the long-legged wading birds, their food sources and habitat.

The leak occurred on Tuesday morning, when an Exxon pipeline ruptured in the 13-mile waterway between Staten Island and New Jersey.

There have been three earlier spills in and around the Arthur Kill this year, the most serious being a leak of 567,000 gallons of oil from an Exxon pipeline on Jan. 1.

Last year, the consortium, Longhorn Partners Pipeline, took over an 18-inch-wide, 430-mile-long Exxon pipeline that had been carrying crude from the West Texas fields into Houston and the Gulf Coast refineries.

The rupture of an underwater Exxon pipeline has leaked as much as 500,000 gallons of heating oil into the Arthur Kill between Staten Island and New Jersey.

Similiar questions about liability have come up in connection with an accident last month in which an Exxon pipeline dumped 567,000 gallons of heating oil into the strait between Staten Island and New Jersey.

After all, that accident was minor compared with a 1990 disaster, when an Exxon pipeline broke and began leaking heating oil into the waterway.