The oil has been seeping into Newtown Creek for decades, causing a stench and leaving a sheen on the waterway that separates Queens and Brooklyn. Now, 55 years after a massive spill, the citizens of Greenpoint are headed to court to try to get their neighborhood cleaned up.

Joined by two City Council members and the president of Brooklyn, residents of Greenpoint and nearby Maspeth, Queens, are mounting a multipronged legal attack against Exxon Mobil to force the company to remove the oil that remains after it allegedly spilled 17 million gallons into Newtown Creek in 1950.

“They polluted our land, and now they should pay to clean it up,” a council member of Queens, Eric Gioia, said. Mr. Gioia, who represents the area on the Queens side of Newtown Creek, yesterday announced that a federal lawsuit has been filed against the oil giant. The suit, which includes as plaintiffs the council member representing Greenpoint, David Yassky, and the Brooklyn president, Marty Markowitz, was filed last week and joins a 2004 complaint filed by Riverkeeper Incorporated, a nonprofit group representing Greenpoint residents.

The lawmakers and their constituents want a judge to find Exxon Mobil liable for the oil spilled into 3.5-mile-long creek and to force the company to act aggressively to remove it. Under two 1990 agreements with the state, Exxon Mobil, which denies it is liable for the contamination of Newtown Creek, has been working to remove the oil released from its former facilities in Brooklyn by pumping it into recovery wells. The company says it has eliminated nearly 9 million of the estimated 17 million gallons. “Unfortunately, that just takes time,” a company spokesman, Brian Dunphy, said of the removal process.

Residents say the company has been far too slow. “It still bubbles up. You still see oil plumes in the water,” a longtime Maspeth resident and community board member, Anthony Nunziato, said.

Mr. Nunziato said the oil plumes and vapors have ruined what was once a pristine waterway and crucial pipeline from the East River, and that an accelerated cleanup would go hand in hand with a revitalization of Brooklyn’s waterfront.

The contamination of Newtown Creek dates to a 1950 tank explosion that spread millions of gallons of oil through the ground across 55 acres of Greenpoint, which was then home to several major refineries. The leak went unnoticed for nearly three decades before the Coast Guard discovered the plume in 1978.

In dispute is the source of the oil seeping into the creek. Exxon Mobil says the oil simply isn’t the company’s responsibility. It answered the Riverkeeper complaint with a denial of all charges, which Mr. Dunphy said were “not supported by the facts and are unfounded.”

The lawsuit alleges that the oil spilled in the 1950 leak originated from a refinery of Exxon Mobil’s predecessor, Mobil Oil. Exxon Mobil, however, says the oil likely came from a refinery of Paragon Oil Company, which is now Chevron. A spokesman for Chevron said the origin of the oil has not been identified and that the company is working with the state Department of Environmental Conservation to pinpoint the source by early next year.

“They’ve essentially been pointing the finger at each other,” the chief investigator for Riverkeeper, Basil Seggos, said of the oil companies.

Although Exxon Mobil does not accept the lawsuit’s claim that it is liable for the spill, Mr. Dunphy said the company is stepping up its efforts to remove the oil, as part of its agreements with the state’s environmental agency. He said that by the end of the year, the company will have added four recovery wells to the area since 2004, bringing the total to 17. “We do take our environmental responsibilities very seriously,” Mr. Dunphy said.

The lawsuit filed by Riverkeeper and joined by Messrs. Gioia, Yassky, and Markowitz is only part of the legal campaign against the oil companies. A California-based law firm filed a separate suit in a Brooklyn court last month seeking damages for “negligent, willful, and/or wanton actions” on the part of Exxon Mobil, Chevron, and BP.

The firm, Girardi & Keese, rose to fame for its class action suit against Pacific Gas & Electric that became the basis for the 2000 film “Erin Brockovich.” Ms. Brockovich is a consultant on the Newtown Creek suit, which Girardi & Keese filed on behalf of about two dozen Greenpoint residents.

The claim focuses on damage to the residents’ property value allegedly caused by oil pollution, an attorney on the case, Justin Bloom, said. But Mr. Bloom said investigators also would seek evidence linking the contamination to significant health problems in the neighborhood.

Mr. Dunphy disputed the notion that either the oil or its vapors were a health danger, as the seepage was “adequately below ground” and not linked to any usable water supplies. He said the company believes there “are no health or safety impacts from our plumes in the area.”