‘‘The injured man was initially breathing by himself and then his heart stopped beating. Paramedics were able to restart his heart. They also put a large needle into either side of his chest to reinflate his lungs. Some relatives were also treated for emotional distress.’’

Mr Jaske said it was lukcy that no one else had been injured.

‘‘The explosion happened just before seven o’clock. If it was a couple of hours later when people were leaving for work or school there certainly would have been many more people in the street and the results could have been catastrophic.’’

Stadium Circuit resident Phillip Mariette walked past the van with his partner Kellie about a minute before it exploded.

‘‘We’d gotten to the sale centre just down the road, heard this explosion, turned around, saw this plume of smoking going up in the air and some debris,’’ he said.

‘‘I turned around and ran back, saw the van catching fire and then just little explosions going off,’’ he said.

Mr Mariette said he had been ‘‘pretty lucky’’ to miss the explosion.

‘‘[If] we had been a minute later, we would have been walking right past it.’’

Mary Koulas and her husband Ignatius live in the area and were awoken at 6.45 when they heard the explosion.

‘‘The whole house shook,’’ she said.

Neighbour PJ, who lives one street away from Stadium Circuit, said the blast was followed by screams, believed to be from the young man's mother, who collapsed at the scene.

"It felt like our house had been picked up and dropped," PJ said. "I came downstairs and our picture frames were all over the floor. I heard someone scream out for help and I came outside and saw the woman standing over her son."

Metropolitan Fire Brigade Commander Andrew O’Connell said a leak from a tank containing flammable gas was the likely cause of the explosion. Several tanks were stored in the back of the van, he said.

‘‘That’s most likely the culprit. Our investigations are focusing heavily on the flammable gas containers that are stored in the rear of the vehicle,’’ he said.

‘‘What caused them to leak and what caused them to ignite, we’re unaware of at the moment. That will have to come out as part of our investigation.’’

Commander O’Connell said fire investigators were unsure if the leaking gas was sparked by the van’s ignition or locking system.

He said up to 15 houses in the street had been damaged by the force of the explosion.

‘‘There is debris everywhere, strewn about 150 metres in every direction,’’ he said.

‘‘Most of the houses in the vicinity have all their windows blown in. There’s been debris which has gone up and back through roofs and pierced roofs and doors that have been dislodged. It’s a horrific scene.’’

Commander O’Connell said it was lucky no one else was nearby at the time given how much debris was thrown about.

Lauren, a nearby resident, told 3AW ‘‘the earth shook’’ when the explosion occurred.

"I live in Waverley Park and the whole estate shook. It was massive," she said. "Everyone ran out to their balconies to see what happened."

Commander O’Connell said it was not the first time firefighters had encountered a van that had exploded because of a gas leak.

Two years ago a van exploded outside a house in Chelsea Heights when a spark was triggered by the vehicle’s remote locking system and ignited a leaking gas cylinder. Two young apprentices were lucky not to be injured.

Police are appealing for anyone who witnessed the explosion to contact Crime Stoppers on 1800 333 00.