BP crews have abandoned efforts to place a large dome over one of two leaks at the bottom of the Gulf of Mexico, turning now to a smaller version known as a “top-hat”.
About four feet wide and five feet tall, the new device is a fraction of the size of the dome and is intended to be placed directly over the leak's source.
The dome failed late Friday because it was filled with hydrates, or crystals, formed by rapidly cooling gas inside its chamber. It was several storeys tall, and weighed about 70 tonnes.
The top-hat will be much smaller, with less water inside and therefore less chance of hydrates forming, said Doug Suttles, chief operating officer of BP. It will also be heated with methane.
“We think these two additions, to go along with the smaller size, should provide an opportunity to deal with the problems we encountered with the first dome,” Mr. Suttles said Monday, acknowledging his “disappointment” with the dome, which is now not part of BP's plan.
“At the moment, we don't have plans to use that larger dome, but it's still available to us. It's still sitting on the sea floor.”
Crews are also getting closer to sorting out how they might blast mud and cement into the pipes to permanently seal them - an action known as a “junk shot.” Mr. Suttles expects they may be able to try this with the next 10 to 14 days.
“I know that sounds very basic, but it's actually quite a complex technique,” he said. “We're currently gathering final diagnostic data to ensure that is a viable option.”
One concern is that it will burst more holes in the leaking pipe. BP documents have shown that a worst-case scenario would far exceed the 210,000 gallons a day that officials estimate are currently leaking.
“Part of our planning is to ensure we don’t end up with another leak point if we attempt this,” Mr. Suttles said.
Another long-term solution is a relief well, which crews continue to drill but will take over two months to finish.
The slick continues to threaten the American Gulf coast, after the BP rig exploded on April 20 and sank two days later. Winds have pushed the slick to the west, relieving fears in Mississippi, Alabama and Florida but posing a major threat to Louisiana, to which the sunken-rig was closest.
Louisiana is considered particularly vulnerable, because much of its coast is marsh from which oil wouldn't be easily removed.
The National Oceanic Atmospheric Administration forecasted that thin sheens of oil would continue to wash up around Venice, LA, a staging area for the response, as well as barrier islands to the east that have already been hit and marshes to the west. Thicker oil was forecasted to remain offshore through Thursday.
Mr. Suttles and U.S. Coast Guard Rear Admiral Mary Landry said Monday they've now burned off about 13,000 barrels of oil (the equivalent of about two-and-a-half days of leakage). They also have skimmed nearly 100,000 gallons of oily water up off the surface, though the percentage that is oil is unclear.
Both operations are made possible by the calm weather the region has had over the past few days.
“When the weather is cooperative, I think we can have a very significant impact in terms of fighting this offshore, which is a big part of our attempt,” Mr. Suttles said Monday.
Asked whether oil had hit Port Eads in Southern Louisiana, as was claimed Sunday, Adm. Landry said she did not have confirmation.
“We're ready for this, should it come ashore,” Adm. Landry said, saying they've only had confirmed impact on Louisiana's barrier islands to the east.
Crews continue to spray chemical dispersants on the top of the water to break apart the oil, sending it below. Environmentalists have objected to the process, as using one toxin to fight another.
Adm. Landry says crews are “constantly evaluating” the effect of their strategies. “When we've done surface dispersants, we have done this through a very measured and thoughtful approach,” she said Monday.
Greenpeace, however, said it doesn't appear the government is doing enough to monitor the effects of the chemicals.
“They should have a massive science program out there - water column sampling, sediment sampling... I don't see it,” said environmentalist Rick Steiner, a former University of Alaska professor.
“They're blowing it as far as I can tell,” he added. “There's no win here. It's all lose. And we've learned from every marine oil spill in history that there's little you can do about it once it's in the water. You've lost the battle.”
About a dozen oiled birds have been recovered so far in the leak, said Mark Musaus, deputy director of the U.S. Fish and Wildlife Service's southeast region. Two had recovered and were set to be re-released in Florida Monday.
