ATLANTA — Another offshore oil facility caught fire in the Gulf of Mexico Thursday morning, sending 13 workers into the water to be rescued by boat, and sending enough petroleum into the water to create a mile-long-by-100-foot-wide sheen, according to the US Coast Guard.

The cause of the accident is not yet known and is under investigation. It comes more than four months after BP’s Deepwater Horizon rig blowout, which killed 11 offshore workers and resulted in the largest offshore oil spill in U.S. history. The government and BP are still working on the ultimate plug of that well, which has not leaked since mid-July.

Among environmentalists and liberal lawmakers, reaction was swift.

“”In the wake of the BP catastrophe, this is an extremely disturbing event,”” said Rep. Henry A. Waxman, D-Calif., chairman of the House Energy and Commerce Committee, who has led a congressional investigation into the BP spill. “”I call on the administration to immediately redouble safety reviews of all offshore drilling and platform operations in the gulf and take all appropriate action to ensure safety and protection of the environment.””

In a Thursday afternoon news conference, Louisiana Gov. Bobby Jindal said that the oil platform’s operator, Mariner Energy, reported that all of the site’s seven active wells had been “”shut in,”” meaning they were not leaking oil. Though a fire was still burning on the platform, Jindal said the company told officials that it was being fed by an oil product stored on the platform.

“”That’s a very important point,”” Jindal said — and one that may differentiate this disaster from the BP fire, which was fed by an uncontrollable gush of oil from the wild well below.

Thursday’s incident occurred further west than the BP blowout, about 102 miles off the Louisiana shore, on a shallow-water oil and gas platform south of Terrebonne Bay, said Eileen Angelico, a spokeswoman for the Bureau of Ocean Energy Management, Regulation and Enforcement.

The US Coast Guard received the fire report at 9:20 a.m. CDT, according to U.S. Coast Guard Petty Officer Casey Ranel. Workers on a nearby oil facility reported that an explosion occurred on the platform, Ranel said.

The 13 workers, wearing flotation suits, apparently jumped in the water, which is about 340 feet deep. They were eventually evacuated by boat, said Patrick Cassidy, a Mariner spokesman, in an interview with CNN.

Cassidy, the company spokesman, said he didn’t know the circumstances that caused the workers to go overboard.

“”The expectation’s that they shut in production and then evacuated the facility,”” he said. “”They were picked up from a life raft, picked up by a boat, and are on their way to facilities onshore.””

A Coast Guard e-mail to congressional offices said that the platform workers reported beginning emergency shutdown procedures before abandoning it, but that they success of those procedures was “”unknown.””

According to the e-mail, the company told the Coast Guard that the platform does not have a “”standard”” blowout preventer, the device of last resort used to shut off the flow of oil and gas from a wild well.

Jindal said it was possible, though not confirmed, that some type of “”nonstandard”” blowout preventer may have been used on the platform.

Jindal and the Coast Guard reported that that one worker was injured, but the company, in a news release, said that there were no injuries. All 13 of the workers were on a shore supply vessel, Jindal said, and would soon be flown by helicopter to a Louisiana hospital to be checked for injuries.

Coast Guard Petty Officer Matthew Masaschi said that the company had sent three vessels to combat the fire, which was contained, but still burning, as of Thursday afternoon.

The Maritime press release said that during the last week of August, production on the facility, which was technically in a federal lease area called Vermillion block 380, averaged about 9.2 million cubic feet of natural gas per day and 1,400 barrels of oil and condensate.

Mariner Energy focuses on oil and natural gas exploration and production in the Gulf of Mexico. Among all operators in the U.S. outer-continental shelf, Mariner ranked the eighth-largest in natural gas production and 24th in oil production.

By the end of 2009, Mariner Energy had interests in nearly 350 federal offshore leases, with more than 110 of those in development. Today, the company has ties to more than 80 deep-water wells.

The firm has been aggressively ramping up its expansion in the Gulf of Mexico since 1996. Some of those exploration and development projects had been in deeper waters, ranging from 1,300 feet up to 7,100 feet. But the one area the business has been particularly active in the Permian basin oil field, off the coast of Texas. As of Dec. 31, 2009, Mariner’s net acreage in the Permian Basin was nearly 150,000 acres.

Apache, another petroleum company based in Houston, announced plans to buy Mariner one week prior to the BP oil spill. The $3.9 billion cash and stock deal is still pending.

It had expected to be finalized by next month.

It was the company’s wide swath of drilling acreage and off-shore leases in the Gulf of Mexico, both closer to shore and further out in the deep water, that attracted Apache Corp.’s attention, said Apache spokesman Robert Dye.

“”We’re monitoring the situation closely,”” Dye said. “”We’re still trying to see what sort of damage has happened out there, and if there were any hydrocarbons that were spilled.

As of 2008, the Vermilion 380 site was Mariner Energy’s “”largest field in the Gulf of Mexico Shelf by reserves,”” according to the company’s 2008 annual report. The field, which consisted of 50 percent oil and 50 percent natural gas, was large enough and robust enough to convince Mariner Energy to drive several wells into it.

The rig had been active and in production prior to the explosion, Dye said.

Activist Democrats on Thursday said the fire demonstrated the need to bring more stringent regulation to the offshore industry.

Jacqueline Savitz, senior campaign director for the environmental group Oceana, said that the Obama administration should maintain a recently enacted moratorium on oil and gas drilling that has been strongly opposed by both the oil industry and Louisiana politicians.

“”We cannot afford to lose any more human lives, nor can we tolerate further damage to the gulf and its irreplaceable ocean ecosystems,”” Savitz said.

The administration has said it plans to keep the moratorium in place until Nov. 30 at the latest.