An oil platform in the Gulf of Mexico off the Louisiana coast caught fire on Friday killing at least two people, the Coast Guard said.
Four others were airlifted to hospital and two workers are "missing and possibly overboard," petty officer Ryan Tippets told CNN.
"There are several commercial vessels on scene and also coast guard vessels are en route to assist in the search of the missing personnel."
The explosion comes a day after BP reached a deal with the US government to settle criminal charges over the devastating 2010 oil spill which began with an explosion on an offshore rig.
There was no immediate news on whether any oil was spilling from the burning platform, which is in relatively shallow water about 25 miles (40 kilometers) south of the beach town of Grand Isle.
"We haven't received any reports of any kind of oil being released into the water," Tippets said, adding that the Coast Guard has not yet arrived on scene to assess the situation.
WWLYTV news reported that the fire has been extinguished and that the rig was not producing oil at the time of the explosion.
It posted a video online showing thick black smoke pouring up from the platform.
The station also reported that 28 people were on board the rig operated by Houston-based Black Elk Energy.
Neither the Coast Guard nor Black Elk Energy were immediately available to comment further.
BP agreed Thursday to pay a record $4.5 billion in US fines for the 2010 Gulf of Mexico oil spill and pleaded guilty to 14 counts including felony manslaughter in the deaths of 11 workers.
It took 87 days to cap BP's runaway Macondo well 5,000 feet (1,500 meters) below the water surface as it spewed some 4.9 million barrels (206 million gallons) of oil into the Gulf of Mexico and blackened beaches in five states.
The deadly blast aboard the BP-leased Deepwater Horizon rig unleashed the biggest marine oil spill in the industry's history and the worst environmental disaster to strike the United States.
It led to major regulatory reforms but critics say the offshore oil industry has not worked hard enough to improve its safety record.