HOUSTON (Reuters) – One worker is missing and six are 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.

There were eight people on the oil platform at the time, she said; one was uninjured. What caused the explosion and fire has not been determined, she said.

Fire officials were still trying to extinguish the blaze late on Sunday, she said.

Police were notified of a loud explosion about 7:18 p.m. local time by residents, and soon after received a call from the platform that a boat carrying injured was on its way to shore, said Kenner, Louisiana, Police Lt. Brian McGregor.

The injured on the boat were taken by ambulance to two local hospitals, he said.

Some of the workers suffered severe burns from the fire, he added. Other details were not immediately available.

East Jefferson General Hospital, which received some of the injured, declined to comment on the number of treated or on the type or extent of their injuries.

A WVUE Fox 8 television video posted on Facebook showed an industrial structure ablaze with smoke as lights flashed nearby.

Clovelly is the only oil company operating in Lake Pontchartrain, according to its former president, Harald Werner. It has two or three active oil and gas wells at the site, he said.