INVESTIGATORS were today preparing to sift through the rubble of an industrial unit in a bid to establish the cause of a major blaze.

Explosions rocked a row of garage units on the Salthouse Mills estate in Barrow yesterday as a plume of black smoke darkened the sky.

The building housed vehicles, tyres and fuel and is understood to be used by banger car enthusiasts.

Roger Exley, Barrow station manager for Cumbria Fire and Rescue Service, said: "Fire appliances from across south Cumbria attended Salthouse Mills. "It was a major fire. On arrival we found a fully engulfed building. Our priority was about the safety of the people who were evacuated when we got there.

"There were a number of vehicles and a significant amount of tyres, diesel and petrol."

Crews from Barrow, Ulverston, Grange and Broughton attended, with 30 firefighters tackling the blaze.

Richard Wilson, 37, is an engineer at United Utilities which has a base next to the Salthouse Mills estate.

He dialled 999 after seeing smoke from the adjacent units.

Mr Wilson said: "I climbed up one of our structures to see over the fence. The roof was on fire and within 10 minutes it had spread from one side to the other. The speed was incredible. You could see the roof dropping in. Within about 30 minutes it had totally caved in."

The fire was in a building containing three garage units. The roof of the building has collapsed but the walls are still standing.

Mr Exley said the significant fireball explosion is understood to have been from a large amount of fuel stored in a tank. Firefighters were a safe distance away from the explosion.

An image of the fireball was captured by Roose man Graham Taylor. Mr Taylor, 64, a former power plant worker, went to investigate after hearing explosions.

He said: "The noise came before the actual explosion. I was using my camera to take pictures and didn't think I had caught it. When I looked back and saw what I had, I was gobsmacked.

"Obviously you just hope and pray that everyone is OK and that no-one is injured."

Mr Exley said a full fire investigation is being carried out.

As well as the billowing smoke, many people across Furness saw a black smoke halo which was the aftermath of the mushroom effect of the explosion.