An explosion has torn through an offshore oil rig in the Gulf of Mexico, west of the site of the blast in April that caused a huge oil spill.
The blast, which threw 13 people into the water, was reported by a commercial helicopter company about 0930 local time (1330 GMT), Coast Guard Petty Officer Casey Ranel said.
It is unclear if the structure is a production platform or a drilling rig.
Seven helicopters, two airplanes and four boats are en route to the site.
The blast occurred around 130km (80 miles) south of Vermilion Bay along the central Louisiana coast.
Mr Ranel said smoke was reported but it is unclear whether the rig is still burning.
All 13 workers who fell into the Gulf are accounted for, the Coastguard said. On person is reportedly injured
"[They] are all wearing some sort of an immersion suit that protects them from the water," Coast Guard chief petty officer John Edwards told MSNBC.
The platform, which is not currently producing, is owned by Mariner Energy and is located in approximately 2,500ft (762m) of water, the Coast Guard said.
"Right now we're focused on search and rescue and then, ultimately, as this thing progresses we're going to be looking into the cause," Mr Edwards said.
The latest explosion comes more than four months after an blast ripped through a Deepwater Horizon rig run by BP, causing about hundreds of million gallons of oil to be released into the Gulf of Mexico.
http://www.bbc.co.uk/news/world-us-canada-11014645