(CNN) -- A production platform has exploded 80 miles off the central coast of Louisiana, with 13 people overboard, including one injured, the Coast Guard said Thursday morning.

All 13 people have been accounted for, said Petty Officer Bill Colclough of the Coast Guard. All are headed to a hospital in Terrebonne Parish, he said.

Colclough told CNN that authorities are trying to determine the cause of the blast, and that the platform apparently is still on fire. Asked whether a leak has resulted from the explosion, he said the structure "was not actively producing any product."

"We do not know if there are any additional concerns of pollution," Colclough said.

He said Coast Guard helicopters and cutters are en route to the scene.

The explosion happened south of Vermilion Bay on the Vermilion 380, which is owned by Mariner Energy, said John Edwards, a chief petty officer with the Coast Guard in New Orleans, Louisiana.

Mariner Energy is a leading independent oil and gas exploration and production company in the Gulf of Mexico. About 85 percent of the company's production comes from offshore assets, with a growing share of that coming from deepwater developments.

The explosion comes nearly five months after the Deepwater Horizon drilling rig exploded April 20, killing 11 people and causing oil to gush into the Gulf of Mexico, leading to one of the worst environmental disasters in U.S. history.

That oil rig, contracted by BP, had 126 workers, and sank after three days of the U.S. Coast Guard's efforts to put out flames.

U.S. agencies and BP worked to stop oil spilling from the ruptured well, an onslaught of oil into the Gulf waters that could hurt the region for years. The well has been capped since July 15, and no new oil is flowing into the Gulf.

The failure of the well's blowout preventer trigged the April 20 explosion, and crews are expected to remove the equipment from the well since it may hold valuable forensic evidence as to why it failed.

Unlike that rig, the Vermilion is a production platform that can "host" a drilling vessel like the Deepwater rig, said Gene Beck, an associate professor of Petroleum Engineering at Texas A&M University.

"My suspicion would be, it was a natural gas explosion," he said.