An explosion rocked an offshore oil drilling platform, sending a column of fire into the sky and touching off a frantic search at sea Wednesday for 11 missing workers.
Most of the 126 workers on the rig Deepwater Horizon escaped safely after the explosion about 10 p.m. Tuesday, the Coast Guard said. Three were critically injured.
The rig, more than 50 miles southeast of Venice on Louisiana's tip, was still burning Wednesday afternoon. It was tilting about 10 degrees. There was no estimate of when the flames might be out.
Within minutes of the explosion the Coast Guard sent helicopters to pull injured workers from the platform, reports CBS News correspondent Kelly Cobiella.
Helicopters and boats searched the Gulf of Mexico for any sign of the workers who had not been accounted for.
"We're hoping everyone's in a life raft," Coast Guard Senior Chief Petty Officer Mike O'Berry said. However, earlier reports that a raft had been spotted were erroneous, Coast Guard officials said at an evening press conference.
The Coast Guard said there were 17 workers evacuated by air and sea Wednesday morning but not all required hospital stays. Three were in critical condition, said Rear Admiral Mary Landry, the Coast Guard commander for the surrounding district.
The other 98 workers were being brought in by boat and were expected ashore Wednesday evening.
Landry said that search and rescue operations - using both boats and infrared-equipped airplanes can go on day or night and will continue until there is no reasonable hope of finding the missing workers.
When the explosion happened, the rig was drilling but was not in production, according to Greg Panagos, spokesman for its owner, Transocean Ltd. in Houston. The rig was under contract to BP PLC. BP spokesman Darren Beaudo said all BP personnel were safe but he didn't know how many BP workers had been on the rig.
Adrian Rose, vice president of Transocean, said crews were doing routine work before the explosion and there were no signs of trouble.
The company currently doesn't know what caused the explosion and is focused on search and rescue and supporting workers' families.
The rig went into service in January and has been inspected three times - including once this month - Interior Department Deputy Secretary David Hayes said at the press conference. He said he was not aware of any safety violations identified in those inspections.
The Deepwater Horizon is one of the largest of the 90 drilling rigs now operating in the Gulf of Mexico. At 396 feet long and 256 feet wide, it's 36 feet longer and nearly 100 feet wider than a football field, Cobiella reports.
Working in the oil industry is more dangerous than working in , Cobiella reports. On rigs in the Gulf of Mexico alone there have been 59 fatalities, more than 1,300 injuries and 853 fires since 2001.
Coast Guard environmental teams were on standby in Morgan City, La., to assess any environmental damage once the fire was out.
BP is currently mobilizing an oil spill response team with seven specialized vessels currently on site or en route, said David Rainey, the company's vice president of Gulf of Mexico exploration. He said there has been little or no actual pollution so far because virtually all of the flowing oil and gas is burning off - but that could change after the vertical pipe is plugged to stanch the flow and extinguish the fire.
The Interior Department's Minerals Management Service - in cooperation with the Coast Guard - will launch investigation "when the time comes" Hayes said.
Rose and Rainey said the burning rig is listing as much as 10 degrees and its stability is being monitored by engineers. It is too early to tell whether it will be damaged beyond repair, they said.
According to Transocean's website, the Deepwater Horizon is 396 feet long and 256 feet wide. The semi-submersible rig was built in 2001 by Hyundai Heavy Industries Shipyard in South Korea. The site is known as the Macondo prospect, in 5,000 feet of water.
The rig is designed to operate in water up to 8,000 feet deep and has a maximum drill depth of about 5.5 miles. It can accommodate a crew of up to 130.
A semi-submersible rig is floated to a drilling site. It has pontoons and a column that submerge when flooded with seawater. The rig doesn't touch the sea floor, but sits low in the water, where it is moored by several large anchors.
Last September, the Deepwater Horizon set a world deepwater record when it drilled down just over 35,000 feet at another BP site in the Gulf of Mexico, Panagos said.
"It's one of the more advanced rigs out there," he said.
Panagos did not know how much the rig cost to build, but said a similar rig today would run $600 million to $700 million.
Workers typically spend two weeks on the rig at a time, followed by two weeks off. It is equipped with covered lifeboats with supplies to allow them to survive for extended periods if they must evacuate.
Total offshore daily production in the Gulf of Mexico is 1.7 million barrels in federal waters; 6.6 billion cubic feet of natural gas per day is produced in those waters. There are about 35,000 workers offshore in the Gulf at any one time, according to MMS.
Joe Hurt, a regional vice president for the International Association of Drilling Contractors, said working on offshore oil rigs is a dangerous job but has become safer in recent years thanks to enhanced training, improved safety systems and better maintenance.
"In recent years, there's been a lot more money available and more money spent on training and safety," he said.
Transocean has 14 rigs working in the Gulf and 140 worldwide. There are 42 deep water rigs either drilling or doing workovers - upgrades and maintenance - in depths of 1,000 feet or greater in the Gulf of Mexico, according to the federal Minerals Management Service.
Since 2001, there have been 69 offshore deaths, 1,349 injuries and 858 fires and explosions in the Gulf, according to the agency, which did not break down the cause of the deaths, the severity of the injuries, or the size of the fires and explosions.