NEW ORLEANS, La. (AP) — Another oil rig exploded and caught fire Thursday off the Louisiana coast, spreading a mile-long oil sheen in the Gulf of Mexico west of the site of BP's massive spill. All 13 crew members were rescued.

Coast Guard Petty Officer Bill Coklough said the sheen, about 100 feet wide, was spotted near the platform. Firefighting vessels were battling the flames.

The company that owns the rig, Houston-based Mariner Energy, did not know what caused the blast, which was reported by a helicopter flying over the area.

Crew members were found floating in the water, huddled together in survival outfits called "gumby suits."

"These guys had the presence of mind, used their training to get into those gumby suits before they entered the water. It speaks volumes to safety training and the importance of it because, beyond getting off the rig, there's all the hazards of the water such as hypothermia," Coast Guard spokesman Chief Petty Officer John Edwards said.

The crew was being flown to a hospital in Houma. Coast Guard Cmdr. Cheri Ben-Iesau said one person was injured, but the company said there were no injuries.

Seven Coast Guard helicopters, two airplanes and three cutters were dispatched to the scene.

The platform is in about 340 feet of water and about 100 miles south of Louisiana's Vermilion Bay. It's location is considered shallow water, much less than the approximately 5,000 feet where BP's well spewed oil and gas for three months after the April rig explosion.

Responding to any oil spill in shallow water would be much easier than in deep water, where crews depend on remote-operated vehicles access equipment on the sea floor.

The rig is a fixed platform that was in production at the time of the fire, according to a homeland security operational update obtained by The Associated Press.

The update said the platform was producing 58,800 gallons of oil and 900,000 cubic feet of gas per day. The platform can store 4,200 gallons of oil.

Louisiana Gov. Bobby Jindal said Mariner Energy officials told him there were seven active production wells on the platform, and they were shut down shortly after the fire broke out.

White House press secretary Robert Gibbs said President Barack Obama was in a national security meeting at the time of the accident.

"We obviously have response assets ready for deployment should we receive reports of pollution in the water," Gibbs said.

The platform is about 200 miles west of BP's blown-out well. A company report said the well was drilled in the third quarter of 2008.

Federal authorities have cited Mariner Energy and related entities for 10 accidents in the Gulf of Mexico over the last four years, according to safety records from the Bureau of Ocean Energy Management, Regulation and Enforcement.

The accidents range from platform fires to pollution spills and a blowout, according to accident-investigation reports from the agency formerly known as the Minerals Management Service.

In 2007, welding sparks falling onto an oil storage tank caused a flash fire that slightly burned a contract worker. The Minerals Management Service issued a $35,000 fine.

Mariner Energy Inc. focuses on oil and gas exploration and production in the Gulf. In April, Apache Corp., another independent oil company, announced plans to buy Mariner in a cash-and-stock deal valued at $3.9 billion, including the assumption of about $1.2 billion of Mariner's debt. That deal is pending.

On Friday, BP was expected to begin the process of removing the cap and failed blowout preventer, another step toward completion of a relief well that would put a final seal on the well. The Deepwater Horizon exploded April 20, killing 11 people and setting off a three-month leak that totaled 206 million gallons of oil.