YOBS set fire to a tower at the Kimberley Brewery site this week, police have said.
The blaze – which spread across two floors – was started at 7am on Wednesday morning.
Arsonists set fire to a pile of rubbish and firefighters had to break into the tower with axes and crowbars to get at the blaze.
A fire service spokesperson said: “The fire was started in an external wooden tower.
“There was a hole in the floor where the bags used to be lowered when it was a working brewery, so the fire quickly spread to both floors.”
Firefighters from both Eastwood and Stockhill were called to the incident in Hardy Street.
Police have now issued a safety warning, and an appeal for information if anybody witnesses suspicious behaviour there in the future.
Inspector Deborah Regan from Eastwood Police Station said: “This building is unsafe and could pose a serious risk to anyone who enters it.
“I would urge anyone who sees people trying to get into the building to contact us on 101, or call Crimestoppers anonymously on 0800 555111.”
No arrests have yet been made and nobody was injured.