Coast Guard: Gulf oil slick comes from device used in 2010 spill

An undersea camera confirms that an oil slick discovered in the Gulf of Mexico came from a 100-ton device on the seafloor that BP had used several weeks after the 2010 oil spill in a failed attempt to cap its runaway Macondo well, the U.S. Coast Guard  said Thursday.

The oil  is not coming from the Macondo itself, which was sealed in a relief well operation months after the 2010 blowout.

Less than 100 gallons of oil per day is leaking from the containment device, the Coast Guard said. The oil will continue to dribble out slowly for the time being. Officials are trying to figure out the best course forward.

BP said the Coast Guard has determined the sheen is not feasible to recover and does not pose a risk to the shoreline, but the Coast Guard said it is still considering what should be done.

“The latest survey marks the third time since the Macondo well was permanently sealed in September 2010 that it has been visually inspected at the seafloor and confirmed not to be leaking,” BP said in a statement.

Transocean, which owned the Deepwater Horizon drilling rig that exploded after the Macondo blowout, declined to comment on the Coast Guard’s news release. Eleven workers died in the accident, and the government estimates that more than 200 million gallons of crude spewed from the well a mile below the surface of the water.

According to the Coast Guard, remote operated vehicles deployed from the offshore construction vessel Skandi Neptune collected oil samples on Wednesday from the underwater site of the Deepwater Horizon incident to determine the source of the surface sheen.

An ROV also inspected the original Macondo well area including the wreckage of the Deepwater Horizon, debris, relief wells, and the riser pipe that once connected the wellhead to the rig,  and observed no oil leakage from that area. Oil samples collected will be used for lab analysis, the Coast Guard said in its statement.

“The Coast Guard is further evaluating what is believed to be seepage from the containment dome to determine how best to respond,” said Capt. Duke Walker, Federal On Scene Coordinator for the Deepwater Horizon response.

The Coast Guard said it will release video footage of the undersea inspections. A spokesman later said it could be a few days before that happens.

U.S. Rep. Edward Markey of Massachusetts, a top Democrat on the House Committee on Natural Resources, said BP should immediately release the video “so that the American people and the scientific community can see for themselves that no oil is leaking from the well itself.”

“In addition, BP should seek to recover all oil trapped inside the failed containment dome or any other debris that remains on the seafloor in order to prevent even more oil from spilling into the environment,” Markey said.

The new development contradicts BP’s assertion that it believed the source of the oil was likely the bent riser pipe that once connected the rig to the well head, where a mix of oil, drilling mud and seawater were trapped after the top kill operation, which was another failed attempt to stop the oil from spewing.

The device where the oil found Sept. 16 originated is a four-story box with a dome on top that was placed over the well in early May 2010. Officials abandoned the mission after tiny ice crystals, called hydrates, formed on the device. They placed the containment device on the seafloor near the well and it has been there ever since.

What is clear, the government and BP say, is that the oil is not coming from the well itself. A tighter fitting cap placed over the well in July 2010  stopped the flow of oil to the sea. A few months later, BP sealed the well for good from below using a relief well to pump in cement.

Confirmation that an oil sheen reported last month in the Gulf of Mexico is consistent with oil from BP’s blown-out well comes at a critical time, just as talks intensify about resolving penalties and fines from the Deepwater Horizon disaster 2 ½ years ago.

Scientists have said that residual oil from the well and the wreckage of the Deepwater Horizon rig and other equipment on the seafloor that was used to cap the well could be dredged up for months and years to come.

The recent discovery has brought renewed attention and concern by officials along the Gulf and in Washington.