WASHINGTON — A new federal study has found that an oil leak in the Gulf of Mexico that began 14 years ago has been releasing as much as 4,500 gallons a day, not three or four gallons a day as the rig owner has claimed.
The leak, about 12 miles off the Louisiana coast, began in 2004 when a Taylor Energy Company oil platform sank during Hurricane Ivan and a bundle of undersea pipes ruptured. Oil and gas have been seeping from the site ever since.
Taylor Energy, which sold its assets in 2008, is fighting a federal order to stop the leak. The company asserts that the leaking has been slight — between 2.4 and four gallons per day. Oil plumes from the seafloor, Taylor executives have said, are from oil-soaked sediment that has formed around the platform, and any gas rising from the bottom is the natural product of living organisms.
“The results of this study contradict these conclusions,” the report, issued on Monday by the National Oceanic and Atmospheric Administration and Florida State University, concluded.
Using sonar technology and a newly developed method of analyzing oil and gas bubbles rising through the water, scientists determined that the plumes are the result of oil and gas released from multiple wells. They also found that as many as 108 barrels of oil, or just over 4,500 gallons, have spilled into the Gulf each day as a result of the episode.
“While it is feasible that the heavily oiled sediments in and around the erosional pit could be contributing to oil in the water column, the chemical nature and volume of oil and gas measured precludes sediments from currently being the major source of oil to the marine environment,” the report says.
The researchers also noted that their findings indicated lower levels of leakage than a handful of other recent estimates. Government attorneys in a federal court filing last year, for example, estimated that up to 30,000 gallons were leaking daily from the destroyed wells.
The study comes as the Trump administration works to roll back a key offshore-drilling safety regulation that was put in place after the 2010 Deepwater Horizon explosion in the Gulf of Mexico. That disaster, the worst oil spill in United States history, killed 11 people and released an estimated 4.9 million barrels into the sea.
The administration also has moved to significantly expand offshore drilling in United States waters. Last year, the Interior Department proposed opening almost the country’s entire coastline to drilling, although that plan now faces delays while court challenges are addressed.
The Taylor Energy spill had remained largely out of the national spotlight until researchers monitoring satellite images of the Deepwater Horizon zone noticed “persistent oil slicks that appeared unrelated to the 2010 spill,” according to the report.
Taylor Energy said in a statement that it had not been able to study the underlying data in the new government report and that the company wanted “verifiable scientific data about the leak and a scientifically and environmentally sound solution.”
Daniel Jacobs, an associate professor of management at Loyola Marymount University in Los Angeles who wrote “BP Blowout: Inside the Gulf Oil Disaster,” said the findings showed that the Trump administration “should be treading lightly” on its aggressive efforts in favor of drilling.
“This is an unresolved, ongoing leak 14 years later,” Mr. Jacobs said. “This is yet another indication that we are not ready to expand offshore drilling.”
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