BATON ROUGE, La. -- Federal regulators have relaxed a pollution monitoring requirement for a company responsible for a decade-old oil leak in the Gulf of Mexico, a slow-motion spill that could last another century.
In 2008, the Coast Guard ordered Taylor Energy Company to conduct daily flights over the site of its leak to visually monitor chronic oil sheens that often stretch for miles off Louisiana's coast.
That requirement remained in effect until December, when the Coast Guard amended the order to reduce the minimum number of required overflights to twice a week.
Regulators didn't announce the change at the time. The Coast Guard confirmed details of its new order on Tuesday in response to an Associated Press inquiry.
Coast Guard Chief Petty Officer Bobby Nash said flights are often cancelled due to weather and "other safety issues," and they rarely detect the presence of oil that could be recovered from the water's surface.
"Based on this historical knowledge and consistent patterns of sheening near the site, the new overflight frequency will target calm days when there is greater likelihood to observe dark, recoverable product on the water's surface," Nash said in a statement he attributed to "Unified Command," which includes federal regulators and Taylor Energy itself.
Government experts believe oil is still leaking at the site where waves whipped up by Hurricane Ivan in 2004 triggered an underwater mudslide, which toppled a Taylor Energy-owned platform and buried a cluster of its oil wells under mounds of sediment. Last year, regulators estimated the leak could last a century or more if left unchecked.
Taylor Energy has said nothing can be done to completely eliminate the persistent slicks. The New Orleans-based company claims the sheens are coming from residual oil oozing from sediment on the seafloor.
In 2008, the Coast Guard initially ordered the company to fly over the leak site twice a day but reduced the requirement to once a day in 2009.
"The frequency of overflights has historically been reviewed and revised where conditions warrant modification," Nash said.
Environmental groups led by the New York City-based Waterkeeper Alliance sued Taylor Energy in 2012, accusing the company of withholding information about its government-supervised efforts to stop the leak. The company pledged to share more information with the public when it reached a settlement with the groups last year.
"The government making this change without notifying the public is on par with its complete lack of transparency from the beginning," said Waterkeeper Alliance staff attorney Larissa Liebmann.
When slicks are visible during flights, a Taylor Energy contractor submits a pollution report to the Coast Guard's National Response Center. Last year, an Associated Press analysis of data identified roughly 2,300 pollution reports on the Taylor Energy site since the leak began.
SkyTruth, a West Virginia-based environmental watchdog group, has used satellite images and Coast Guard reports to track the leak since 2010. The group counts only 40 Coast Guard reports for Taylor Energy's leak site since Jan. 1.
The AP's investigation last year revealed evidence that the leak is worse than the company, or government, reported. Presented with AP's findings, the Coast Guard provided a new leak estimate that's about 20 times larger than one cited by the company in a court filing last year.
SkyTruth estimated last year that between 300,000 and 1.4 million gallons of oil spilled from the site between 2004 and 2015 — and it sees no end in sight. Satellite images from April 23 show a slick measuring 27 miles long and 3,500 feet wide and at its widest point, the group noted Monday in a Facebook post.
John Amos, SkyTruth's president, questioned why regulators would ease the company's monitoring obligations.
"Why would we drop our vigilance about what's happening at the site knowing that the job isn't done?" he said. "As shoddy and as demonstrably inaccurate as these (company-submitted pollution) reports are, they're the only public record of what's been happening out there since the leak began in 2004."
Taylor Energy, which sold all its offshore leases and oil and gas interests in 2008, says it has spent more than $480 million on its efforts to stop the leak. The company sued the federal government in January to recover more than $400 million in additional money that it set aside for leak-related work.