Oil spills like the Deepwater Horizon and the Exxon Valdez are embedded in the environmental consciousness, so much so that they're essentially shorthand for any other spills that occur.

But there are spills that don't get as much attention — and maybe they should. For instance, the Taylor oil spill has been quietly leaking what could be millions of gallons of oil into the Gulf of Mexico since 2004, six years before the Deepwater Horizon spill.

Never heard of it? You're not alone. This oil spill has barely made a ripple in public discourse, although after more than 14 years of continuously spewing oil into the Gulf, that may finally be changing. Several recent studies, including one by U.S. government scientists, suggest the leak is much worse than previously reported. And amid this increased attention, a new containment system has finally begun collecting a "significant portion" of the oil as it escapes into the Gulf.

While the Taylor Energy Company has estimated the site is leaking three to five gallons of oil per day, for example, a June 2019 study by the U.S. National Oceanic and Atmospheric Administration (NOAA) concluded it's actually leaking between 378 and 4,536 gallons of oil daily. That is dramatically higher than the company's estimate, but it's also lower than some other recent investigations have found.

A teenage oil spill

A satellite view shows Hurricane Ivan on Sept. 15, 2014, about 170 miles south of the Alabama coastline. NASA/GSFC, MODIS Rapid Response/Wikimedia Commons

The Taylor oil spill started in 2004 following Hurricane Ivan. An oil platform, Mississippi Canyon-20, and pipeline belonging to Taylor Energy was damaged and sank on Sept. 15, 2004, following a mudslide caused by the hurricane. The structure, according to a paper prepared by Taylor Energy officials and described in a 2013 NOLA.com article, "was subsequently located lying in an almost horizontal orientation and almost entirely buried in sediment up to 100 feet deep, approximately 900 feet from its original location and in approximately 440 feet of water."

The oil leak, located about 12 miles off the Louisiana coast and 7 miles north of the Deepwater Horizon site, went relatively unnoticed by news outlets. Taylor Energy reported it at the time to the Coast Guard's National Response Center (NRC), as required by the Oil Pollution Act, but neither Taylor or the NRC raised public awareness, according to the Washington Post. The company worked to keep the leak out of the national spotlight, citing concerns over a loss of reputation and proprietary information about its business practices, according to a legal settlement from 2015. If it hadn't been for the Deepwater Horizon spill, the Taylor spill might have gone unnoticed for even longer.

A shadow of another slick

A boat sails through an oil slick caused by the Deepwater Horizon spill. If not for that spill, the Taylor spill may not have been brought to public attention. kris krüg/Wikimedia Commons

In 2010, during the Deepwater Horizon spill, local activists performed flyovers of the area to monitor the extent of that spill. In the process, however, they noticed a shadow of another slick that didn't match the main spill.

"They said it couldn't have been coming from the BP spill, and sure enough, it wasn't," Marylee Orr, the executive director of the Louisiana Environmental Action Network (LEAN), told CNN. "It was coming from the Taylor Well."

It took time, however, for organizations like LEAN, Apalachicola Riverkeeper and other Louisiana environmental groups to get answers. In 2012, LEAN and the others sued Taylor Energy, beginning a three-year litigation process that culminated in the aforementioned 2015 settlement. In addition to detailing the state of the platform, Taylor Energy claimed the sheen near the site was "residual" and that "there is no evidence to suggest" the presence of an ongoing leak.

Just how much oil has been leaked?

The site of the Taylor oil leak is about 12 miles off the coast of Louisiana. NOAA

The site of the Taylor oil leak is about 12 miles off the coast of Louisiana. (Map: NOAA/Google)

Since disclosing the leak to the National Response Center, Taylor maintained the stance that the leak was minor. Surveys conducted by organizations like SkyTruth and investigations by the Associated Press countered these claims, and in 2015, the U.S. Coast Guard released a leak estimate that, according to Greenpeace, was about 20 times larger than what Taylor Energy has reported in court filings.

The scope of the Taylor spill has proven difficult to quantify. SkyTruth, using data given to the Coast Guard by Taylor Energy, estimates that from 2004 to 2017, between 855,421 and 3,991,963 gallons of oil have leaked into the Gulf. John Amos, founder of SkyTruth, told CNN that this estimate was almost certainly too low as it relied on data supplied by Taylor Energy.

The Deepwater Horizon spill resulted in an estimated 176.4 million gallons (4.2 million barrels) of oil, according to CNN.

A Department of Justice report, released in September 2018, relied on satellite data instead of Taylor Energy's numbers. This report suggested about 250 to 700 barrels a day (that's roughly 10,000 to 30,000 gallons a day), are leaking into the ocean.

This still image shows oil bubbles recorded by a bubblometer during a 2019 study of the Taylor oil spill. NOAA

In a technical report released in June 2019, scientists from NOAA and Florida State University estimated the leakage to be between nine and 108 barrels (378 to 4,536 gallons) of oil per day. The researchers used acoustic technology as well as a new device called a "bubblometer" to calculate the flow rates. They also characterized the composition of the oil and gas discharge, and "conclusively established that active releases from multiple wells at the site, rather than from contaminated sediments, are the primary source of oil and gas entering the marine environment at the site."

These are not "final definitive government estimates," the agency told the Associated Press, adding that it will continue to investigate the leak.

Cleaning up the mess

The latest findings come at a critical time for both the federal government, represented by the Department of the Interior, and Taylor Energy. The entities have been involved in a protracted legal battle as Taylor Energy seeks to recover more than $400 million left from a $666 million trust fund established in 2008 that was to be used to clean up the Mississippi Canyon-20.

According to the Washington Post, Taylor Energy and its contractors were asked to locate the the wells under the mudslide and cap them. If that was not possible, a device needed to be created to contain the leak. Taylor Energy did not drill or bore through the mudslide, however, due to concerns about exacerbating the spill. The company has plugged about a third of the 21 wells and erected a shield of some kind that was supposed to prevent the oil from leaking.

Taylor Energy, which sold all its oil and gas assets to Korea National Oil Corporation and Samsung C&T; Corporation in 2008, maintains just one employee, company President William Pecue. Pecue has argued the leak is an "act of God under the legal definition."

In May 2019, the Coast Guard reported the oil leak was finally being at least partially contained. Lawyers for the government filed a status report stating that a new containment system "is now fully installed and operating as planned." The system is collecting about 1,260 gallons of oil per day, according to NOAA.

"For the first time since 2004, the response team is collecting a significant portion of the oil being released at the MC20 site," the agency said in a report released in late June, nearly 15 years after the leak began.