Firefighters have remained at the scene of a fire where a derelict mill is believed to be in danger of collapsing.Ten fire crews were initially called to tackle the fire off Thornton Road, near Tetley Street, in Bradford, at about 18:20 BST on Tuesday.Internal parts of the building have crumbled and the fire service said crews were at the scene damping down.No one was thought to have been injured, although surrounding roads are still closed for safety reasons.A West Yorkshire Fire Service spokeswoman said a structural engineer was called to the scene on Monday evening because the five-storey mill was to be believed in danger of collapse.Investigations are continuing to establish the cause of the fire.Steve Rhodes from the service said: \"The fire took hold very, very quickly and it spread to all five floors and there was a risk to buildings in front, adjoining it and the buildings at the side.\"Student Rachel Hughes, who saw the mill\'s roof fall down, said: \"Everyone was running towards the smoke to see what it was. It smelt strong and you could feel the heat a way away.\"We watched the fire for about half an hour and then the roof fell down. It was the largest noise, like thunder.\"