MIAMI – Another offshore oil rig exploded Thursday in the Gulf of Mexico, an unsettling echo of British Petroleum’s deep-sea blowout less than six months ago, but this time it appears there won’t be another environmental catastrophe.

The platform produced mostly natural gas and a small amount of oil — 1,400 barrels a day, according to the rig’s owner, Houston-based Mariner Energy. A mile-long ribbon of light sheen was seen near the rig about 100 miles south of Louisiana, but both the Coast Guard and Mariner said there was no indication of a continuing leak.

Coast Guard Cmdr. Cheri Ben-Iesau said the blast, which forced 13 workers to leap into the water where they were rescued, wasn’t comparable to the Deepwater Horizon accident, which exploded in April, killing 11 workers and leaking about 60,000 barrels a day for months.

“It’s a much smaller platform in much shallower water,” she said.

Still, critics immediately seized on the accident to bolster arguments that offshore energy operations are too risky to continue — at least without stringent new safeguards — or expand into new areas, such as off Florida.

Sarah Bucci, field associate for Environment Florida, released a statement that was echoed by the National Audubon Society, the National Wildlife Federation and Greenpeace: “President Obama should need no further wake-up call to permanently ban new drilling.”

The House energy committee, led by Rep. Henry Waxman, D-Calif., sent Mariner Chief Executive Officer Scott Josey a letter asking for a briefing on the blast, which left the rig billowing smoke for much of the day.

Jim Noe, executive director of the Shallow Water Energy Security Coalition, an industry group, said critics were jumping to conclusions. The platform wasn’t a drilling rig, he said.

“We should wait for the facts before we use what happened today on a production platform as a reason to stop offshore drilling, especially when the incident didn’t have anything to do with offshore drilling,” he said.

The Houston Chronicle reported that records from the U.S. Bureau of Ocean Energy Management, Regulation and Enforcement — formerly known as the Minerals Management Service — show Mariner has had at least 13 Gulf accidents since 2006, including several rig fires.

The company issued a brief statement saying all 13 workers had been rescued without injury, no slick was evident during an initial overflight and that it would cooperate in investigating the cause. Mariner officials told CNBC that crews were sandblasting at the time of the explosion. They said the active production wells on the platform were shut down shortly before the fire broke out.

“The platform is still intact and it was just a small portion of the platform that appears to be burned,” sid Mariner Energy spokesman Patrick Cassidy.

White House press secretary Robert Gibbs said the administration has “response assets ready for deployment should we receive reports of pollution in the water.”

Photos from the scene showed at least five ships floating near the platform. Three of them were shooting great plumes of water onto the machinery. Light smoke could be seen drifting across the deep-blue waters of the Gulf. late afternoon, the fire was out.

The captain of the boat that rescued the platform’s 13 crew members said his vessel was 25 miles away when it received a distress call Thursday morning.

The Crystal Clear, a 110-foot boat, was in the Gulf doing routine maintenance work on oil rigs and platforms. When Capt. Dan Shaw arrived at the scene of the blast, the workers were found huddled together in life jackets. They were thirsty and tired after being in the water for about two hours.

“We gave them soda and water, anything they wanted to drink,” Shaw said. “They were just glad to be on board with us.”

Shaw said the explosion was so sudden that crew members did not have time to get into lifeboats. They did not mention what might have caused the blast.

“They just said there was an explosion, there was a fire,” Shaw said. “It happened very quick.”

The crew was flown to a hospital in Houma. The Coast Guard said one person was injured, but the company said there were no injuries. All of the crew members had been released by Thursday evening.

Unlike the Deepwater Horizon, a floating rig drilling in 5,000 feet of water, the Vermilion platform is a permanent rig operating in 340 feet of water. That was shallow enough to allow it to keep operating under an Obama administration moratorium that has halted deep-water drilling until at least Nov. 30.

Federal records and the 2010 company financial statement said the rig, known as Vermilion 380 because of its location 90 miles south of Louisiana’s Vermilion Bay, was among dozens of platforms damaged by Hurricane Ike in 2008.

The company, in a financial statement issued in March, reported it had temporarily suspended operations to conduct underwater structural repairs and had reduced production until the facility was upgraded. Mariner said last month that the facility averaged 9.2 million cubic feet of natural gas per day and 1,400 barrels of oil and condensate.

According to the financial statement, the rig has five wells and produced about 1.1 billion cubic feet of natural gas and liquid natural gas last year. The company claimed oil constituted about half of the field’s reserves.

The Coast Guard’s Ben-Iesau said it appeared the rig’s “tree” — a fitting that regulates the flow of oil and gas known as a Christmas tree in industry parlance — had shut down the wells Thursday. But it remained unclear whether the platform was operating at the time of the blast.

The explosion happened the same day there were continuing signs of progress in the Gulf’s recovery from the nation’s worst oil spill caused by a leak about 200 miles from Thursday’s explosion.

The Associated Press reported that BP engineers removed a temporary cap from its now-sealed well, a necessary step before the company can meet government demands to replace the failed blowout preventer before completing two relief wells.

Federal fisheries managers also reopened another 5,130 square miles of Gulf waters to fishing, including lifting a shrimping restriction in the last small stretch restricted off the Florida Panhandle, declaring seafood in those waters safe. That leaves 43,000 square miles closest to BP’s well, about 18 percent of the Gulf, still off limits to fishing.

There are about 3,400 platforms operating in the Gulf, according to the American Petroleum Institute. Together they pump about one-third of America’s domestic oil, forming the backbone of the country’s petroleum industry.


McClatchy Newspapers and The Associated Press contributed to this report.