Search and rescue teams were deployed after a roof collapsed at a factory building at an industrial complex.
Emergency services were called to the Victoria Industrial Centre on Victoria Street in Accrington to reports of an “explosion” shortly after 6am on Monday, October 9.
Lancashire Fire and Rescue Service said no-one is believed to have been in the building at the time and no injuries have been reported.
Victoria Street has been closed off by police after rubble fell onto the road and is set to remain shut for ‘several hours’.
Specialist urban search and rescue teams are examining the building and paramedics are on stand-by at the scene.
John Taylor, of Lancashire Fire and Rescue Service, said: “We were called at 6.05am to reports of an explosion. I don’t think it necessarily was an explosion but the roof collapsed on a building.
“They weren’t sure that anybody was in the building, but from what the police have gleaned from interviews it’s indicating that no-one was.
“Police are there and ambulances are there too as a precaution along with our urban search and rescue, who are specialist firefighters who have the equipment and skills for building collapses.”
He said a passer-by made the initial call believing that a building had collapsed.
He added: “There’s rubble in the road so Victoria Street has been shut off and my colleague at the scene reckons it will be shut for several hours yet.
“They are going to have to clear a lot of rubble, get building inspectors in and do all those assessments and will be there for a while yet.
“The main message we want to get out to the public is to stay clear of Victoria Street.”
A Lancashire Police spokesperson said: “Part of a factory roof has collapsed.
“The fire brigade are there assessing the structural integrity. We don’t believe that anybody was inside at the time it collapsed.
“We are merely assisting in terms of road closures.”
Chris Waring, incident commander, told the Observer: "Just after 6am there was a report of a collapsed structure from a member of the public.
"We mobilised three appliances and our urban search and rescue team. When we arrived the scene was as it is now.
"There was utilities water leaking and the scene was obviously unsafe. We did a quick hazard search to try and determine if anyone was trapped inside."
He added: "As the incident protracted we got our aerial ladder platform to the scene and also requested an air support unit (drone). At an early stage a request was made for a search and rescue dog but that was cancelled when we confirmed no one was inside.
"We have now got the local authority building inspector on the scene and we will have conversations with the mill owner over how to handle the next stage. There’s a potential for demolition to be required.
"The road closure will be ongoing for the next few hours minimum but then maybe longer term road closures will need to be put in place subject to what the risk assessment says."