Faulty design cited in Gulf oil spill

NEW ORLEANS -- The blowout preventer that should have stopped the BP oil spill cold failed because of faulty design and a bent piece of pipe, a testing firm hired by the government said yesterday in a report that appears to shift some blame away from the oil giant and toward those who built and maintained the 300-ton device.

At least one outside expert said the findings cast serious doubt on the reliability of all the other blowout preventers used by the drilling industry.

The report by the Norwegian firm Det Norske Veritas is not the final word on the Deepwater Horizon disaster last April that killed 11 workers and led to more than 200 million gallons of oil spewing from a BP well a mile beneath the Gulf of Mexico.

But it helps answer one of the lingering mysteries nearly a year later: why the blowout preventer that sat at the wellhead and was supposed to prevent a spill in case of an explosion didn't do its job.

The report cast blame on the blowout preventer's blind shear rams, which are supposed to pinch a well shut in an emergency by shearing through the well's drill pipe. In the BP crisis, the shear rams couldn't do their job because the drill pipe had buckled, bowed and become stuck, the DNV report said.

The 551-page report suggested that blowout preventers be designed or modified in such a way that the shear rams will completely cut through drill pipe, regardless of the pipe's position.

The blowout preventer was made by Cameron International and maintained by Transocean Ltd.

"This is the first time . . . that there has been a clear design flaw in the blowout preventer cited," said Philip Johnson, a University of Alabama civil engineering professor. "My reaction is, 'Holy smokes, every set of blind shear rams out there may have this problem.' "