INVESTIGATORS say they could be working into next week to determine the cause of a massive blaze close to the town centre.

The fire, which destroyed an engineering works, in Tonge Moor Road, Bolton, on Thursday afternoon, caused havoc for rush-hour commuters.

The road was closed after a gas cylinder, which threatened to explode, was found in the building by firefighters.

Diversions were put in place along a 200-metre stretch, between Turton Street and Scowcroft Street.

They remained for almost 24 hours, finally being lifted at 12.40pm yesterday.

Fire crews were still securing the site yesterday.

Thirty people had to be evacuated as 50 firefighters tackled the blaze at the offices and workshop of Lace Control Systems.

Vinny Simpson, fire service borough commander, said: "There are fire crews still on site and we have reduced the hazard zone to allow traffic to flow freely.

"There is now only a very minimal risk from the gas cylinder.

"The upper floor of the building has collapsed on to the lower floors and it doesn't look promising that the building will be fit for any use.

"At present, it is too dangerous to send our investigation officers into the building, so it could be next week before we are able to ascertain the cause of the fire."

A 100 metre exclusion zone was yesterday still in place around the site.