Buckhannon, W.Va. ? As the investigation into the Sago Mine disaster took shape Monday, the best hope for firsthand details about the explosion and its aftermath lay in critical condition, fighting a fever.

Doctors treating sole survivor Randal McCloy Jr. declined to speculate on when the 26-year-old would fully wake up from a medically induced coma or comment on the extent of any brain damage he suffered in the tragedy that killed 12 fellow coal miners.

But physicians said McCloy’s brain stem appeared to be normal, and that a fever is common for patients in intensive care. McCloy was breathing on his own, although he remained connected to a ventilator as a precaution, and was responding to stimuli, doctors said.

“He is likely one of the longest survivors of this sort of exposure, not only carbon monoxide, but the other circumstances in the mine, for about 42 hours,” said Dr. Julian Bailes, a neurosurgeon at West Virginia University’s Ruby Memorial Hospital in Morgantown.

The disaster was the worst coal-mining accident in West Virginia since 1968, when 78 miners were killed in a mine explosion in Farmington.

Federal and state mine safety officials pledged to hold joint public hearings on the accident. Meanwhile, Sens. Robert C. Byrd and Jay Rockefeller, both D-W.Va., called for hearings into coal mine safety.

Byrd said federal mine safety officials would be called to testify before a Senate subcommittee that would hold hearings into the disaster beginning Jan. 19.

Among the questions investigators are sure to ask: Could the trapped miners have walked out under their own power, instead of following their training and waiting for a rescue that arrived too late?

Another focus will be the miscommunication that led to the mistaken belief that 12 of the trapped miners had been rescued alive. That sparked a celebration at a nearby church that was halted three hours later by the devastating news of their deaths.

State officials have not started interviewing witnesses and said they did not know when they would begin.

Also Monday, funerals were held for three more miners. Two funerals are scheduled today.