Fireboats spraying oil platform.Firefighting vessels managed to put out the platform blaze after five hours.Photo: Greenpeace USANEW ORLEANS — An oil platform explosion Thursday in the Gulf of Mexico forced the crew to dive into the sea and threatened further damage to waters still recovering from the BP disaster.

Fire engulfed the offshore platform 100 miles south of the Louisiana coast shortly after 10:00 a.m. EST and massive plumes of gray smoke billowed into the sky as rescuers rushed to fish out the workers.

Photographs showed the 13-strong crew linking arms as they bobbed up and down in special flotation suits before being plucked out of the water by a nearby rig. Three U.S. Coast Guard helicopters and a commercial chopper then transported them to a mainland hospital. All escaped serious injury.

Workers told rescue crews they managed to shut down the wells before evacuating the platform and had spotted a thin sheen of oil spreading for about a mile.

Crews from three firefighting vessels managed to extinguish the blaze after about five hours and the oil sheen was no longer visible by the time the Coast Guard arrived.

“The fire is out, and Coast Guard helicopters on scene and vessels on scene have no reports of a visible sheen in the water,” Coast Guard Eighth District Chief of Staff Captain Peter Troedsson told reporters. “Responders remain vigilant for any evidence of oil on the water,” he added.

The incident ignited fresh criticism of the oil and gas industry as the region struggles to recover from the BP disaster, the largest ever maritime oil spill.

“The BP disaster was supposed to be the wake-up call, but we hit the snooze button. Today the alarm went off again,” said Michael Brune, executive director of the Sierra Club. “The oil industry continues to rail against regulation, but it’s become all too clear that the current approach to offshore drilling is simply too dangerous.”

“How many times are we going to gamble with lives, economies, and ecosystems?” asked John Hocevar, director of Greenpeace USA’s oceans campaign. “It’s time we learn from our mistakes and go beyond oil.”

The Mariner Energy platform that went ablaze on Thursday was operating in relatively shallow water, about 340 feet, and was not a drilling rig. It had been producing approximately 1,400 barrels of oil and condensate and 9.2 million cubic feet of natural gas per day, the Texas-based company said.

The White House said early in the day that it was monitoring the situation and reserved judgment until more information was available. “We will continue to gather information as we respond, we obviously have response assets ready for deployment, should we receive reports of pollution in the water,” White House Press Secretary Robert Gibbs told reporters.

Gibbs declined to say whether the president believed inspections of rigs in the Gulf of Mexico were moving fast enough in the wake of the BP disaster.

It was also unclear how this incident would affect Obama’s moratorium on deepwater offshore drilling, which is being challenged in the courts and has faced harsh criticism from his political foes.

The House Energy and Commerce Committee, which has held a congressional investigation into the BP spill, sent a swift letter to Mariner Energy’s chairman requesting a briefing on the incident.

“In the wake of the BP catastrophe, this is an extremely disturbing event,” said Henry Waxman (D-Calif.), the committee chair. “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.”

The Shallow Water Energy Security Coalition insisted the fire was an “industrial accident” that could have occurred at any industrial site, onshore or offshore.

“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,” said Jim Noe, the group’s executive director.