Seventeen people were injured, three critically, in the blast aboard the Deepwater Horizon, which occurred about 10 p.m on April 20. The rig was about 52 miles southeast of Venice, Louisiana, said Coast Guard Senior Chief Petty Officer Mike O'Berry. As of mid-afternoon on April 21, the rig was still ablaze.

The cause of the explosion is under investigation, but there are no indications it was a terrorist incident, the Coast Guard said.

At the time of the explosion, 126 were on board the rig,

The Coast Guard said it sent helicopters from New Orleans, Louisiana, and Mobile, Alabama, to help evacuate people from the rig and look for the missing. The Coast Guard also sent four cutters to the scene.

Of the 115 workers who were accounted for, 17 were transported by air for medical treatment from the rig. Another 94 people were taken to shore with no major injuries, and four more were transferred to another vessel, according to the Coast Guard.

Several people were hospitalised, including at least two, who were taken to a mobile trauma center.

The company that owns the rig, Transocean Ltd., said most crew members are safe.

CNN