Michael McNally, 40, described how he drove his bus into the centre of the carnage and tried to get as many injured as possible on board.
He said the journey to the hospital, only a few minutes away, was the longest he would ever make in his life.
"It was like a scene from hell," Mr McNally said.
Mr McNally, who is from Omagh and knew many of the casualties, had been at the town's bus depot when he heard the explosion. He and another driver, Aidan McBride, rushed to the scene.
"As we got to the traffic lights the sight was horrendous," he said. What we saw was impossible to imagine. There were bodies lying, people screaming, people digging at buildings with their bare hands trying to get people out from under the rubble. It was just like a scene from Hell.
"People were wandering about in total shock, others were screaming and lying in the road. People were carrying the injured in their arms.
"I just thought: `We will try and get as many people in here as we can because this is carnage.'. There were so many of them. I thought, good God - there's so many.
Mr McNally said people came from everywhere to help and soon there were taxi drivers and driving instructors loading casualties into their cars. "People were coming in minibuses, vans, Jeeps and even taxi men and driving instructors. We took about 25.
"I remember a wee small boy in the front seat who was rigid with fear. He just sat there staring but his mother was hysterical. She kept shouting over and over again: `He'll bleed to death.' Another girl seemed to have a hole in her side. They handed her to me and she put her arm around my neck and when I got home my hair and my uniform were drenched in blood."
They carried the injured into the hospital casualty department but it was so full, that they had to start taking them into the outpatients' ward, he said.
"It was crazy. There were people lying everywhere and blood everywhere like you wouldn't believe," said Mr McNally, who is married with a teenage son and daughter.
So many people had done so much that he did not feel he had done anything heroic, he said.
But he added: "Usually if I saw blood I would run a mile but this just had to be done. It's hard to believe what people can do in these circumstances. So many ordinary people helped out. It's amazing what people can manage to do at times like this."Reuse content