CYLINDERS containing an unknown substance caused a van explosion in which a man died today.

Fire officers said the cylinders caught fire, engulfing the transit van in a fireball at Market Place, Wolsingham, County Durham, at about 6.45am today.

The driver of the van died in the explosion.

The immense blast cause structural damage to nearby buildings, left debris scattered along the street and led to homes being evacuated.

It will be at least 24 hours before people living near the blast scene can return to their homes.

Fire-fighters were this morning waiting for the cylinders in the torn remains of the van to cool down before they could begin their investigations.

Station Manager Tony John of Durham Fire service said: "We believe the explosion was due to a cylinder or cylinders setting alight in the van causing a large explosion at around 6.45am.

"Debris was scattered right down the street."

His colleague, Station Manager Steve Wharton, of Durham Fire Service HQ said: "It was a large explosion in the middle of the market square where extensive debris was littered on the street.

"Property suffered significant damage, it wasn't obvious when we first arrived on scene whether somebody was in the vehicle.

"Our first priority was to control the flames.

"It was fortunate at that time of the day that nobody else was around.

"It could have been a lot worse had it been later on in the day.

"We are taking precautions all day waiting for the cylinders to cool and due to the fact we don't know what is in the cylinders all precautions have to be met to keep the area as safe as possible."

Insp Andy Huddlestone of Durham Police said: "It was a big explosion and there was of damage caused by the debris from the explosion.

"Nobody else was injured other than the driver. This was very fortunate due to the time of day as nobody else was around.

"At least six or seven houses had severe structural damage as a consequence from the explosion.

"The area has been cordoned off and will be for at least 24 hours.

"The A689 at Wolsingham will be closed all day today with diversions put in place.

"Residents are currently finding accommodation with friends and family and will not be allowed back to their residences again for at least 24 hours.

"We cannot specify as to when residents will be allowed back, this is due to the fire service waiting for the cannisters to cool down.

"Investigations will start now and continue over the coming days."