AN investigation is under way after an explosion caused a ferocious fire at an indoor market.

Firefighters were back at Clifford Centre Family Indoor Market, in Stanley, yesterday trying to establish what caused the blaze that tore three holes in the roof.

The explosion happened at 9.50am on Monday and police had to cordon the area off until 10am yesterday, in case three gas cylinders on the site blew up.

Had that happened, it would have destroyed the building and lives could have been lost.

Dozens of people fled the scene as noxious fumes emitted from the fire, which was contained in a shop unit.

But brave worker Robert Dunn was hailed a hero, after staying behind to fight the fire and keep the cylinders cool with water from an internal hose.

Les Greenwood, community safety manager for Durham and Darlington Fire and Rescue, is leading the investigation into the fire.

He said: "We are talking to people who were at the scene where the fire broke out and sifting through the ashes to see what we can find.

"Once we get the rubble out of the way, we can find the source. From that, we will be able to deduce what caused the fire."

The shop unit where the blaze began has been destroyed, with part of its roof hanging down.

The floor is under an inch of stagnant water, filled with charred remnants of the walls of a walk-in chiller. Two stand-up fridge freezers have been buckled by the heat.

There is a lingering smell of burned plastic and wood and the smoke from the fire has affected most of the traders' stock.

Joe Keeler, one of the market's three directors, said he hoped the market would reopen on Saturday, but that it was more likely to be Monday.

He said: "It has come as a shock to everyone, and it has still not quite sunk in, but you have just got to get on with it.

"All of the traders are pulling together and mucking in to get the place cleaned up.

"If any groups are having an organised bonfire, they can come and take as much wood as they like for free."