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GRAND ISLE, La. — An offshore oil platform exploded and was burning Thursday in the Gulf of Mexico about 100 miles off the Louisiana coast. All 13 workers were rescued from the water, the U.S. Coast Guard said.

The explosion aboard the platform, owned by Mariner Energy, occurred west of the site of the April offshore rig blast that caused the massive BP oil spill.

Patrick Cassidy, a spokesman for Mariner Energy, told CNBC that there does not appear to be any oil leaking.

The Coast Guard said the explosion was reported by a commercial helicopter flying over the site around 9 a.m. CDT.

All 13 workers at the platform were plucked from the water by a supply boat and taken to another platform where they were waiting to be picked up by the Coast Guard, the agency said.

"Thirteen people were seen huddled together in the water wearing gumby suits or immersion suits, water protection suits, so we were able to confirm that all people were accounted for," Coast Guard spokesman Chief Petty Officer John Edwards said.

Coast Guard Cmdr. Cheri Ben-Iesau said one of the 13 was reported injured. The extent and nature of the injury was not immediately known.

All the workers were being flown to the Terrebonne General Medical Center in Houma to be checked.

The platform continued to burn several hours hours after the explosion, said Coast Guard fireman Katherine McNamara.

No oil or sheen from the burning platform was seen in the water by Coast Guard helicopters on scene, McNamara said.

Coast Guard Cmdr. Cheri Ben-Iesau said seven Coast Guard helicopters, two airplanes and three cutters were dispatched to the scene from New Orleans, Houston and Mobile, Ala.

In Washington, White House spokesman Robert Gibbs said a federal government response was ready if needed.

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

The Department of Homeland Security said the platform, known as Vermilion Oil Platform 380, was owned by Mariner Energy of Houston. DHS said it was not producing oil and gas.

Company records show that the platform and rig is in 340 feet of water.

Melissa Schwartz, spokeswoman for Bureau of Energy Management Regulation and Enforcement, said the platform was authorized to produce oil and gas at this water depth but had not been recently in active production.

"There were ongoing maintenance activities underway," she said.

Mariner Energy focuses on oil and gas exploration on the Gulf of Mexico. In April, Apache Corp., another independent petroleum 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.

In a prepared statement, the company said it was working with regulatory authorities in response to the explosion.

Vermilion 380 is believed to be a fixed, manned production platform — not a well being drilled for oil, like BP's Macondo well and not a floating rig like the Deepwater Horizon, the Times-Picayune reported.

Lee Hunt, president of the International Association of Drilling Contractors, told the Times-Picayune these types of structures are permanently in place, often with a pipeline or oil and gas and water separation facilities on board.

"It's more like a small offshore refining operation," he told the newspaper.

The platform is about 200 miles west of BP's blown out Macondo well. On Friday, BP was expected to begin the process of removing the cap and failed blow-out preventer, another step toward completion of a relief well that would complete the choke of the well.

The BP-leased rig Deepwater Horizon exploded April 20, killing 11 people and setting off the biggest maritime oil spill in history. The well spewed an estimated 4.9 million barrels of oil into the Gulf before BP was able to cap it in mid-July.