The Coast Guard discovered Saturday that oil is leaking from the damaged well that fed a massive rig that exploded this week off Louisiana's coast, while bad weather halted efforts to clean up the mess that threatens the area's fragile marine ecosystem.
For days, the Coast Guard has said no oil appeared to be escaping from the well head on the ocean floor. Coast Guard Rear Adm. Mary Landry said the leak was a new discovery but could have begun when the rig sank on Thursday, two days after the initial explosion.
"We thought what we were dealing with as of yesterday was a surface residual (oil) from the mobile offshore drilling unit," Landry said. "In addition to that is oil emanating from the well. It is a big change from yesterday ... This is a very serious spill, absolutely."
A robotic camera has determined a pipe leading from the well is leaking oil at an estimated rate of 1,000 barrels or about 42,000 gallons a day, reports CBS News correspondent Don Teague. That's still much less than the worst-case scenario.
By comparison, Exxon Valdez spilled 11 million gallons in Alaska's Prince William Sound in 1989 the worst oil spill in U.S. history.
The oil has formed a 20-by-20-mile slick about 25 times larger than it appeared to be a day earlier, Landry said. Coast Guard officials say they have a third of the world's oil spill cleanup ships in the area already, and they're fighting the spill. The hope is they can contain and skim that oil off the surface until workers can shut off the flow.
BP PLC, which leased the rig and is taking the lead in the cleanup, and the government have been using the remotely operated vehicles to try to stop the leak by closing valves on the well deep underwater. If that doesn't work, the company could drill what's called an intervention well to control the oil flow. But the intervention drilling could take months.
"Over the next several days, we should determine which method is the best one to follow," said Doug Suttles, chief operating officer for BP Exploration and Production. "A huge number of engineers from ourselves, working with (the government) and across the industry are putting together the best technology and know-how to solve this problem."
Complicating efforts to stop the leak is well head's depth at 5,000 feet underwater, said Lars Herbst, the regional director for the Minerals Management Service. Leaks have been fixed at similar depths before, but the process is difficult, he said.
The bad weather rolled in Friday, bringing with it strong wind, clouds and rain that interrupted efforts to contain the oil spill. Coast Guard Petty Officer John Edwards said he was uncertain when weather conditions would improve enough for the cleanup to resume. So far, crews have retrieved about 1,052 barrels of oily water, he said.
The sunken rig may have as much as 700,000 gallons of diesel on board, and an undetermined amount of oil has spilled from the rig itself. Suttles said the rig was "intact and secure" on the seabed about 1,300 feet from the well site.
BP said it has activated an extensive oil spill response, including the remotely operated vehicles, 700 workers, four airplanes and 32 vessels to mop up the spill. The Marine Spill Response Corp., an energy industry cleanup consortium, also brought equipment.
The 11 missing workers came from Texas, Louisiana and Mississippi. Neither the Coast Guard nor their employers have released their names, though several of their families have come forward.
Karl Kleppinger Sr., whose 38-year-old son, Karl, was one of the missing workers, said he doesn't blame the Coast Guard for calling off the search.
"Given the magnitude of the explosion and the fire, I don't see where you would be able to find anything," said Kleppinger, of Zachary, La.
The other 115 crew members made it off the platform; several were hurt but only one remained hospitalized. The most seriously injured worker was expected to be released within about 10 days.
Federal officials had already been working on new safety rules for offshore drilling before Tuesday's blast.
The U.S. Minerals and Management Service is developing regulations aimed at preventing human error, which it identified as a factor in many of the more than 1,400 offshore oil drilling accidents between 2001 and 2007. An MMS review published last year found 41 deaths and 302 injuries during that period.
The cause of Tuesday's blast hasn't been determined.
The Deepwater Horizon was the site of a 2005 fire found to have been caused by human error. An MMS investigation determined that a crane operator on the rig had become distracted while refueling the crane, allowing diesel fuel to overflow. Records show the fire was quickly contained, but caused $60,000 in damage to the crane.
Environmentalists said the rig explosion and oil spill should push the nation to develop new energy sources.
"This should be a wake-up call," said David Helvarg, the president of the Blue Frontier Campaign, a marine conservation group, and author of "Rescue Warriors: The U.S. Coast Guard, America's Forgotten Heroes."
"I would rather risk a 'wind spill' than an oil spill offshore," he said, ruefully pointing out that the source of wind-powered energy can't sully the environment.
More on Louisiana Oil Rig Explosion:
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