POlice say that three people were seen running from the scene.
Five DFB units are at the scene at Shanowen Road in Santry.
Five fire engines were called to the old Cuckoo’s Nest pub in Tallaght last night.
The company is also facing a potential emissions scandal.
All 159 passengers and 13 crew were evacuated.
There are no injuries reported as firefighters continue to douse the flames on the Charles Rennie Mackintosh building.