NEW ORLEANS -- Eleven workers missing from an offshore oil platform may not have escaped after a massive explosion, officials said Thursday.
Crews continued to search by air and water for those missing from the Deepwater Horizon, which burned for nearly a day before sinking into the Gulf of Mexico on Thursday.
Adrian Rose, vice president of rig owner Transocean Ltd., said crew members who survived Tuesday's explosion indicated the missing may have been near the blast and unable to escape. Officials had hoped they might have been able to get to a covered lifeboat with supplies.
The rig was doing exploratory drilling about 50 miles off the coast of Louisiana. Rescue crews have covered a 1,940-square-mile search area by air 12 times and by boat five times.
Carolyn Kemp of Monterey, La., whose grandson, Roy Wyatt Kemp, 27, was among the missing, said family members have been told it's unlikely anyone survived. Roy Kemp would have been on the drilling platform when it exploded.
''They're assuming all those men who were on the platform are dead,'' Carolyn Kemp said. ''That's the last we've heard.''
Other relatives waited anxiously for hourly updates. Family members of one missing worker, Shane Roshto of Amite, Miss., filed a lawsuit in New Orleans on Thursday accusing Transocean of negligence. The suit said he was thrown overboard by the explosion and is feared dead, though it did not indicate how family members knew that was what happened.
The suit also names oil giant BP, which contracted the rig. A Transocean spokesman did not immediately respond to a request for comment and BP wouldn't discuss the suit.
The family of Dewey Revette, a 48-year-old from southeast Mississippi, said he was also among the missing. He worked as a driller on the rig and had been with the company for 29 years.
''We're all just sitting around waiting for the phone to ring and hoping for good news. And praying about it,'' said Revette's 23-year-old daughter, Andrea Cochran.
Transocean Ltd. spokesman Guy Cantwell said 111 workers who made it off the Deepwater Horizon safely after Tuesday night's blast were ashore Thursday, and four others were still on a boat that operates an underwater robot.
Seventeen others hurt in the blast had been brought to shore Wednesday with burns, broken legs and smoke inhalation. Four were critically injured.