An investigation has been launched into the cause of a huge blaze at Pagefield Mill.
At around 4pm on Saturday, firefighters were called to reports of a fire inside the derelict building on Kenyon Road in Swinley.
During the initial call, crews were told that youths had started the fire, which then continued to burn for around three and a half hours, causing extensive damage to the roof.
Flames could be seen coming from the top of the building and onlookers reporting seeing large parts of the roof collapsing.
Seven appliances were in attendance, including two specialist units with aerial equipment so that firefighters could fight the flames from above.
Carl Gleaves, watch manager at Wigan fire station, said: “When we arrived we believed that some youths may still be inside the building so we had to enter, which we didn’t want to do for safety reasons.
“We went in to see if anyone needed to be saved, putting our safety at risk. It seems that the people involved didn’t give any thought to what harm they could be putting emergency workers at.
“It is a real problem site, we are regularly attending there. Although security has been improved, the building is not completely impenetrable.”
It took firefighters until around 7.30pm to douse the flames and make the area safe.
Crews were forced to move inside the building to gain access to the fire.
Police, wearing masks, went from door to door advising residents to keep their windows and doors closed while the incident was ongoing.
Mesnes Park was closed while firefighters tackled the blaze and surrounding roads were cordoned off to protect the public.
Watch manager Gleaves added: “We are urging residents to remain vigilant and call the police if they see anyone at the site.
“We have a meeting with the council to discuss dangerous buildings.”
Police have since launched an investigation into the cause of the fire. Firefighters say that they will be looking into CCTV footage of the surrounding area and speaking to any residents who may have witnessed the events leading up to the blaze.
Anyone with information should contact Greater Manchester Police on 101 or call Crimestoppers anonymously on 0800 555 111.