Work begins to try to capture gushing oil in Gulf

GULF OF MEXICO - Workers began to lower a giant concrete-and-steel box over the blown-out oil well at the bottom of the sea last night in a risky and untested bid to capture most of the gushing crude and avert a wider environmental disaster.

"We haven't done this before. It's very complex and we can't guarantee it," BP spokesman David Nicholas warned.

The 100-ton containment vessel is designed to collect as much as 85 percent of the oil spewing into the Gulf and funnel it up to a tanker. It could take several hours to lower it into place, after which a steel pipe will be installed between the top of the box and the tanker. The whole structure could be operating by Sunday.

The mission took on added urgency as oil started washing up on delicate barrier islands.

The technology has been used a few times in shallow waters, but never at such extreme depths: 5,000 feet down, where the water pressure is enough to crush a submarine. The box - which looks a lot like a peaked, 40-foot-high outhouse, especially on the inside, with its rough timber framing - must be accurately positioned over the well, or it could damage the leaking pipe and make the problem worse.

Other risks include ice clogs in the pipes, a problem that crews will try to prevent by continuously pumping in warm water and methanol, and the danger of explosion when separating the mix of oil, gas and water brought to the surface.

Interior Secretary Ken Salazar halted all new offshore drilling permits Thursday until at least the end of the month.