According to Black Elk Energy, which owns the platform where the explosion happened, the search for the missing worker has intensified. Three dive boats were also included in Monday's search.
Doctors said one of four men burned in the blaze is improving and was in fair condition as of Sunday. Two remained in critical condition and one in serious condition.
The body of another missing worker was found on Saturday. Eleven others were hurt.
Though the names of the victims have not been released, the Philippine Embassy in Washington confirmed the worker whose body was recovered was Filipino, as are the worker who remains missing and four who have been hospitalized.
Authorities have said the blaze erupted Friday morning while workers were using a torch to cut an oil line on the platform.
But the CEO of oilfield contractor Grand Isle Shipyard said the cause of the fire and explosion is unknown and that "initial reports that a welding torch was being used at the time of the incident or that an incorrect line was cut are completely inaccurate." The dead, missing and wounded workers were GIS employees.
The Associated Press contributed to this report.