A TERRIFIED teenager is fighting for his life in hospital after being turned into a human fireball following an horrific explosion at a bus depot.

The 15-year-old was with a 48-year-old man at the compound when it is thought sparks from a welding machine ignited paint thinners, causing an explosion.

Both were burned but the youngster - named by a boss at the depot as Scott Sargeant - was most seriously injured.

He was described yesterday as "very poorly but stable" in the intensive care unit at Newcastle's Royal Victoria Infirmary.

The injured man, Abbey Coaches manager Fred Wren, was recovering at James Cook University Hospital following the explosion.

The terrifying incident happened inside a workshop used to repair coaches at the Abbey Coaches compound in Middlesbrough Road East. A worker at adjacent Town and Country Tyre Services, Stuart Tyreman, told how he and his colleagues rushed to the pair's aid on Saturday, just after 1.30pm.

He said: "I heard a big bang, I couldn't see anything at first, but then I saw the young lad run outside, he was on fire.

"Our boss came out and we ran over. The gaffer told me to get some rags to help put him out. The lad was rollinhg about on the floor in agony, he was screaming - it was terrible.

"We managed to get his trousers off him then I ran inside to put some other small fires out while another man stayed with hime to try and calm him down.

"It was over in minutes, it just happened so quickly. The older guy was burned pretted badly too because when I saw him he had no clothes on, they were all on fire.

"I asked him 'what was it?' and he just said 'paint thinners'."

Mr Tyreman,24, said the horrific images of the teenager's ordeal will stay with him forever.

He added: "It was nasty, not a nice thing to witness. I've been thinking about it ever since."

Police are investigating the explosion and have informed the Health and Safety Executive, who have started their own probe.

Abbey Coaches acting manager, Michael Wearmouth, said: "It is a very tragic incident.

"But at this stage, the only two people who know what really happened are Scott and Fred.

"Scott's a young lad with a great interest in buses and mechanical things, so he often watches the lads while they're doing jobs in the workshop.

"Fred is a craft-trained mechanic and is probably the best one to show anyone how its done.

"He's also very keen on safety and we make a big point of it here - so it is a mystery how this has happened.

"Perhaps there was some sort of fault with the equipment, we just don't know.

"Our thoughts are with Scott and his family and we hope he pulls through soon. He is a popular lad, full of fun. This is a great tragedy."