Fighting Oil: Dome Arrives to Cap Leak

May 6, 2010— -- A metal box weighing more than 100 tons and representing British Petroleum's hopes of stopping spewing oil arrived this morning at the site of the leak in the Gulf of Mexico.

Crews will use a crane during the next few days to lower the dome over the leak. BP hopes it can then funnel the oil to the surface, although officials admit that they're not sure if it will work.

"It has never been done at 5,000 feet below the sea, but that's the option the team is working on," BP Chief Executive Tony Hayward said.

The only tactic that has worked so far is burning the oil. Officials have restarted that strategy now that the weather has improved.

BP will no longer dump tens of thousands of gallons of chemical dispersants a mile below the sea at the site of the leak until environmental-impact tests can be performed.

Near the Chandeleur Islands, a remote chain of barrier islands in eastern Louisiana, a layer of brown slime carpeted the water Wednesday. The slime, which is not as thick as oil, could be the chemical dispersant that had been pumped down to the site of the leak to break up the oil before it reached the surface.

"The dispersants, which are being flown on out there right now and injected into the well, have a very high toxicity level," Louis Miller, the state director of the Mississippi Sierra Club, said.

The company will not say exactly what chemicals make up the dispersant but insists the chemicals are not dangerous. Indeed, BP is still spraying them from the sky.

"With time, this dispersant breaks it up, and it will take care of itself," BP Senior Executive Vice President Bob Fryar said. "That's when nature kicks in and takes care of it."

Homeland Security Secretary Janet Napolitano and Commerce Secretary Gary Locke join with Interior Secretary Ken Salazar today on the Gulf Coast.

A trip last week by Department of the Interior Chief of Staff Tom Strickland raised concerns when it was learned that he was in the Grand Canyon with his wife while his agency was coordinating the federal response effort to the spill.

ABC News' Jake Tapper reported that the trip included white-water rafting, but Obama administration officials said it was "work-focused."

BP said Wednesday that it had successfully capped one of the three leaks at the site. Although that will not slow the flow of oil, BP said it would make the collection work easier going forward.