NEW ORLEANS — A deepwater oil platform that burned for more than a day after a massive explosion sank into the Gulf of Mexico on Thursday, creating the potential for a major spill as it underscored the slim chances that the 11 workers still missing survived.
The sinking of the Deepwater Horizon, which burned violently until the gulf itself extinguished the fire, could unleash more than 300,000 of gallons of crude a day into the water. The environmental hazards would be greatest if the spill were to reach the Louisiana coast, some 50 miles away.
Crews searched by air and water for the missing workers, hoping they had managed to reach a lifeboat, but one relative said family members have been told it's unlikely any of the missing survived Tuesday night's blast. The Coast Guard found two lifeboats but no one was inside. More than 100 workers escaped the explosion and fire; four were critically injured.
Carolyn Kemp of Monterey, La., said her grandson, Roy Wyatt Kemp, 27, was among the missing. She said he would have been on the drilling platform when it exploded.
"They're assuming all those men who were on the platform are dead," Kemp said. "That's the last we've heard."
Jed Kersey, of Leesville, La., said his 33-year-old son, John, had finished his shift on the rig floor and was sleeping when the explosion occurred. He said his son told him that all 11 missing workers were on the rig floor at the time of the explosion.
"He said it was like a war zone," said Jed Kersey, a former offshore oil worker.
An alarm sounded and the electricity went out, sending John Kersey and other workers scurrying to a lifeboat that took them to a nearby service boat, his father said.
"They waited for as many people as they could," Jed Kersey said. He added that his son wasn't ready to talk publicly about his experience.
As the rig burned, supply vessels shot water into it to try to keep it afloat and avoid an oil spill, but there were additional explosions Thursday. Officials had previously said the environmental damage appeared minimal, but new challenges have arisen now that the platform has sunk.
The well could be spilling up to 336,000 gallons of crude oil a day, Coast Guard Petty Officer Katherine McNamara said. She said she didn't know whether the crude oil was spilling into the gulf. The rig also carried 700,000 gallons of diesel fuel, but that would likely evaporate if the fire didn't consume it.
Coast Guard Rear Adm. Mary Landry said crews saw a 1-mile-by-5-mile rainbow sheen with a dark center of what appeared to be a crude oil mix on the surface of the water. She said there wasn't any evidence crude oil was coming out after the rig sank, but officials also aren't sure what's going on underwater. They have dispatched a vessel to check.
The oil will do much less damage at sea than it would if it hits the shore, said Cynthia Sarthou, executive director of the Gulf Restoration Network.
"If it gets landward, it could be a disaster in the making," Sarthou said.
Doug Helton, incident operations coordinator for the National Oceanographic and Atmospheric Administration's office of response and restoration, said the spill is not expected to come onshore in the next three to four days. "But if the winds were to change, it could come ashore more rapidly," he said.
At the worst-case figure of 336,000 gallons a day, it would take more than a month for the amount of crude oil spilled to equal the 11 million gallons spilled from the Exxon Valdez in Alaska's Prince William Sound.
The well will need to be capped off underwater. Coast Guard Petty Officer Ashley Butler said crews were prepared for the platform to sink and had the equipment at the site to limit the environmental damage.
Oil giant BP, which contracted the rig, said it has mobilized four aircraft that can spread chemicals to break up the oil and 32 vessels, including a big storage barge, that can suck more than 171,000 barrels of oil a day from the surface.
Crews searching for the missing workers, meanwhile, have covered the 1,940-square-mile search area by air 12 times and by boat five times. The boats searched all night.
The family of Dewey Revette, a 48-year-old from southeast Mississippi, said he was also among the missing. He worked as a driller on the rig and had been with the company for 29 years.
"We're all just sitting around waiting for the phone to ring and hoping for good news. And praying about it," said Revette's 23-year-old daughter, Andrea Cochran.
Adrian Rose, vice president of rig owner Transocean Ltd., said Thursday some surviving workers said in company interviews that their missing colleagues may not have been able to evacuate in time. He said he was unable to confirm whether that was the case.
Those who escaped did so mainly by getting on lifeboats that were lowered into the gulf, Rose said. Weekly emergency drills seemed to help, he said, adding that workers apparently stuck together as they fled the devastating blast.
"There are a number of uncorroborated stories, a lot of them really quite heroic stories of how people looked after each other. There was very little panic," Rose said.
Coast Guard Petty Officer Kevin Fernandez was the flight mechanic on a helicopter that was the first to respond, about 15 minutes after the explosion. Fernandez said he could see the fire from 80 miles away, with flames rising about 500 feet.
"I was kind of expecting worse" in terms of fatalities, he said. But all the survivors already had made their way from the lifeboats into a supply boat. Fernandez and his crew plucked two critically injured survivors to a nearby rig that had a paramedic on board.
Family members of two missing workers filed separate lawsuits Thursday accusing Transocean and BP of negligence. Both companies declined to comment about legal action against them after the first suit was filed.
The U.S. Minerals Management Service, which regulates oil rigs, conducted three routine inspections of the Deepwater Horizon this year – in February, March and on April 1 – and found no violations, MMS spokeswoman Eileen Angelico said.
The rig was doing exploratory drilling about 50 miles off the coast of Louisiana when the explosion and fire occurred, sending a column of boiling black smoke hundreds of feet over the gulf.
Rose has said the explosion appeared to be a blowout, in which natural gas or oil forces its way up a well pipe and smashes the equipment. Precisely what went wrong is under investigation.
Transocean Ltd. spokesman Guy Cantwell said 111 workers who made it off the Deepwater Horizon safely after the blast were ashore Thursday, and four others were still on a boat that operates an underwater robot. A robot will eventually be used to stop the flow of oil to the rig. He said officials have not decided when that will happen.
Seventeen workers brought to shore Wednesday suffered burns, broken legs and smoke inhalation. Four were critically injured.
Rose said the crew had drilled the well to its final depth, more than 18,000 feet, and was cementing the steel casing at the time of the explosion. They had little time to evacuate, he said.
The explosion is not expected to have a major impact on the oil industry. There are 90 rigs in the offshore Gulf of Mexico either drilling wells or performing work on existing wells, according to the MMS.
"It's a personal tragedy," Arthur Weglein, director of the Mission Oriented Seismic Research program at the University of Houston. "Besides that, it's just one rig less in the deep water."
The explosion came less than a month after President Barack Obama's decision to open portions of the East Coast to oil and gas exploration, and opponents of the move have seized on the blast as a reason to reverse course.
"The bottom line is that when you drill for oil, there is always a risk that not only puts lives on the line, but a risk that puts miles of coastline and the economy on the line as well," Sens. Robert Menendez and Frank Lautenberg, both New Jersey Democrats, said in a statement.
Working on offshore oil rigs is a dangerous job but has become safer in recent years thanks to improved training, safety systems and maintenance, said Joe Hurt, regional vice president for the International Association of Drilling Contractors.
Since 2001, there have been 69 offshore deaths, 1,349 injuries and 858 fires and explosions in the gulf, according to the Minerals Management Service. Coast Guard Senior Chief Petty Officer Mike O'Berry said accidents are rare given that 30,000 people work on rigs there every day.
"They're highly trained. They know the dangers," O'Berry said. "The safety precautions they take are extreme. A testament to that is of the 126, 115 are home today with their families."
Associated Press Writer Holbrook Mohr reported from Jackson, Miss. Associated Press Writers Mike Kunzelman, Cain Burdeau, Janet McConnaughey and Alan Sayre in Louisiana, Chris Kahn in New York and Sofia Mannos of AP Television News contributed to this report.