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Oil Spill Q&A: Why can't the experts stop the oil from leaking?

On Friday, as the first oil oozed ashore in Louisiana and the first birds were cleaned by volunteers, BP marked the end of another week of failing to shut off the source of the spill. Meanwhile, investigations into the cause of the explosion and fire continue. Here is a primer on what has gone wrong:

What caused the spill?

The Deepwater Horizon rig, owned by Transocean Inc. and under contract to BP, exploded and caught fire April 20, then sank two days later. The blast injured 17 rig workers and left 11 others missing and presumed dead. Oil has been pouring out of the well ever since.

Do they know what caused the explosion?

No. Multiple investigations have been launched — by BP (formerly British Petroleum) and various federal agencies. A possible suspect: Halliburton. A suit filed this week by an injured technician on the platform says Halliburton improperly cemented the well. BP — which has paid millions in fines for other oil and gas–related disasters in the last five years — is ultimately responsible for the entire cost of the spill and cleanup, which so far is costing the company up to $7 million a day.

How much oil is pouring out?

Hard to say. Initial reports said there was no leak. Then Sunday, BP officials said a pipe near the ocean floor was leaking 1,000 barrels a day from two breaks. Wednesday night, Coast Guard officials said they had found a third break and now the leak totaled 5,000 barrels a day. If that number is accurate, it would equal the 1989 Exxon Valdez spill in less than two months. A BP official acknowledged Friday that all spill estimates are "highly imprecise," and Department of Homeland Security Secretary Janet Napolitano told reporters they shouldn't get hung up on exact numbers.

Has BP done anything to stop the leaking oil?

The company dispatched six remote-controlled submarines to the ocean floor to try to shut off a valve called a blowout preventer, or BOP. The BOP was supposed to close when the rig exploded, but it did not. No one knows why. So far all other attempts to close it have failed. On Friday, Interior Secretary Ken Salazar said BP should "work harder and faster and smarter to get the job done."

Could this have been prevented?

Maybe. According to the Wall Street Journal, Norway and Brazil require offshore rigs to have a remote-control shut-off switch called an acoustic valve that crews can trigger from a ship to stop the flow of oil. But the switch is not required by the United States. However, the Journal noted, no one knows whether the device would have worked during the Deepwater Horizon explosion and fire.

Could the spill get any worse?

Yes. Kinks in the pipe are constricting the flow, like pinching a garden hose. The Mobile Press-Register obtained a secret government report outlining concerns that sand spewing out of the pipes with the oil was eroding them. The report said National Oceanic and Atmospheric Administration officials fear that if the pipe erodes too much, "the flow could become unchecked, resulting in a release volume an order of magnitude higher than previously thought."

Are there any other options for stopping the spill?

BP officials will try to lower 100-ton metal domes on top of the leaks and funnel the oil up through pipes to storage vessels. They will also begin drilling what's known as a "relief well" nearby, to intercept the oil and plug the leak. That worked with a recent spill off Australia and with the second-worst offshore drilling disaster ever, the 1979 Ixtoc spill off Mexico. The Ixtoc well leaked for nine months until two relief wells were drilled to relieve pressure so the spewing well could be capped.

What's wrong with those options?

The domes have never been tried in water deeper than 350 feet, so no one knows if they will work. Getting them ready will require at least two weeks. As for the relief well, it won't be completed for three months — and all the while, a river of oil will continue to spew.

Information from the Associated Press, the Washington Post and the Christian Science Monitor was used in this report. Craig Pittman can be reached at craig@sptimes.com or (727) 893-8530.

Q&A

Oil Spill Q&A: Why can't the experts stop the oil from leaking? 04/30/10 [Last modified: Monday, May 3, 2010 4:33pm]

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