One worker is missing while six others were injured after an oil production platform operated by a New Orleans company exploded and caught fire in Louisiana’s Lake Pontchartrain late on Sunday, authorities said.

The platform is operated by Clovelly Oil Co, confirmed Donald Mackenroth, a Clovelly vice president reached by phone. He said the cause of the explosion and fire was not clear, and declined to comment on the number of workers on the platform.

“We’ve got a bunch of people at the hospital; we don’t yet know the extent of their injuries,” he said.

The U.S. Coast Guard and local authorities were using boats and a helicopter to search the lake for the missing worker, said Coast Guard Petty Officer Alexandria Preston. Names of the missing or injured were not available.