NEW ORLEANS -- The condition of a Filipino worker seriously burned in an oil platform fire off Louisiana's coast was upgraded to "good" Monday, while one co-worker was in serious condition and two others remained critical.

One worker, identified by the embassy of the Philippines as 42-year-old Elroy Corporal, was killed in the accident. Another is missing. He was identified on the website of Philippines-based DNR Offshore Crewing Services as Jerome Malgapo.

Fifty-year-old Wilberto Ilagan, one of four burn victims taken to Baton Rouge General Medical Center after the accident was the patient whose condition was upgraded to good on Monday. He had earlier been listed as "fair."

Three others were being treated with Ilagan at Baton Rouge General Medical Center. At a news conference in Baton Rouge, doctors said two remained in critical condition; another was in serious condition. Their identities were not released.

The federal Bureau of Safety and Environmental Enforcement is investigating the accident and said it had personnel on the platform Monday.

The National Chemical Safety Board, a government agency that investigates industrial chemical accidents, said it had not decided whether to launch an investigation, but it has sent a list of questions to Black Elk about evidence and possible witnesses. And it has requested documents relating to safety plans and permits in force at the time of the accident, including welding plans.

Gulf Isle Shipyard, Inc., a company that was performing maintenance services on the platform, said in statements Sunday and Monday that a welding torch was not being used at the time of the fire.

Friday morning's fire happened on a shallow-water offshore rig off the coast of Plaquemines Parish. The fire was out within hours and the platform remained structurally sound. It was not producing at the time and the accident did not result in a continuous leak of oil, as happened after the Deepwater Horizon disaster in April 2010.

The dead and injured were among 14 employees and subcontractors working for Grand Isle Shipyard.

Jose Cuisia Jr., the Philippine ambassador to the U.S. Embassy, attended the news conference in Baton Rouge.

"I'm sure that with the special care and attention you've been extending to our four countrymen, our four countrymen will recuperate sooner rather than later," he said.