Oil Spill Growing off Coast after Rig Explosion

The Coast Guard said Tuesday that a sheen of oil that's been covering an area in the Gulf of Mexico since an oil rig exploded off the Louisiana coast is growing.

Eleven people have been missing and presumed dead since the rig exploded and sank last week about 50 miles (80 kilometers) off the southern state's coast.

As of Tuesday morning, oil that leaked from the rig site was spread over an area about 48 miles (77 kilometers) long and 80 miles (129 kilometers) wide at its widest. The borders of the spill were uneven, making it difficult to calculate how many square miles are covered, Coast Guard Petty Officer Erik Swanson said.

"Right now, the weather's in our favor," Swanson said, explaining that the wind was blowing the oil away from shore Tuesday.

But Swanson said the winds could shift later in the week and there was concern about oil reaching the shore.

So far, skimming vessels had collected more than 48,000 gallons (182,000 liters) of oily water, Swanson said.

"Our goal is to fight this thing as far offshore as possible," he said.

The rig was owned by Transocean Ltd. and operated by BP PLC.

Crews used robot submarines to activate valves in hopes of stopping the leaks, but they may not know until Tuesday if that strategy will work. BP also mobilized two rigs to drill a relief well if needed. Such a well could help redirect the oil, though it could also take weeks to complete, especially at that depth.

BP plans to collect leaking oil on the ocean bottom by lowering a large dome to capture the oil and then pumping it through pipes and hoses into a vessel on the surface, said Doug Suttles, chief operating officer of BP Exploration and Production.

It could take up to a month to get the equipment in place.

"That system has been deployed in shallower water, but it has never been deployed at 5,000 feet of water, so we have to be careful," he said.

The spill, moving slowly north and spreading east and west, was about 30 miles (50 kilometers) from the Chandeleur Islands off the Louisiana coast. The Coast Guard said kinks in the pipe were helping stem the flow of oil.

From the air Monday afternoon, the oil spill reached as far as the eye could see. There was little evidence of a major cleanup, with only a handful of vessels near the site of the leak.

The oil sheen was a shiny light blue color, translucent and blending with the water, but a distinct edge between the oil slick and the sea could be seen for miles.

George Crozier, oceanographer and executive director at the Dauphin Island Sea Lab in Alabama, said he was studying wind and ocean currents driving the oil.

He said Pensacola, Florida, is probably the eastern edge of the threatened area, though no one really knows what the effects will be.

"We've never seen anything like this magnitude," he said. "The problems are going to be on the beaches themselves. That's where it will be really visible."

More on Louisiana Oil Rig Explosion:

Oil Rig Cook Haunted by Nightmares Since Blast
Crews Work to Stop Oil Leak in Gulf
Sunken Oil Rig Off Louisiana Coast is Leaking
New Oil-Rig Safety Rules Eyed Before Blast
Officials: Sunken Rig Could Cause Huge Oil Spill
Negligence Lawsuit Filed in Oil Rig Fire
Air Search Resumes for Missing Oil Rig Workers
Air Search Resumes for Missing Oil Rig Workers
11 Still Missing Nearly a Day After Rig Blast
Oil Rig Environmental Concern
The Search for Oil Rig Workers