PITTSBURGH (AP) — Rescuers who found the lone survivor of the West Virginia coal mining tragedy may have reached him just in time, because his lungs were starting to fill up with dust and gases, one of his doctors said Friday.

In the hour before he was discovered, Randal McCloy Jr. lost the ability to cough, sneeze or otherwise control his airway, said Dr. Richard Shannon, speaking for a team of doctors treating McCloy.

The dust and low-lying gases that settled in McCloy’s lungs as he lay on his side caused inflammation in his left lung, Shannon said, adding that stabilizing the inflammation will be important for getting the miner off a ventilator.

‘‘That does constitute a serious issue. ... We are working very diligently with keeping those airways open,’’ Shannon said.

McCloy was taken by ambulance Thursday from a West Virginia hospital to Pittsburgh’s Allegheny General Hospital, where he lay in critical condition in a medically induced coma with brain damage and other injuries from oxygen deprivation.

Doctors stressed it will take time before the extent of the brain damage is known.

Shannon said McCloy’s heart is now functioning properly and his blood test results are improving.

‘‘These are two very, very important milestones as we progress,’’ Shannon said.