An exercise at North Yorkshire's fire training centre ended with a building's roof being destroyed in a blaze. Up to 20 firefighters from Easingwold, Acomb, York and Huntington were called out to the centre in Easingwold on Thursday afternoon to tackle the blaze in a 'smoke house' - used to train firefighters how to deal with smoky conditions.
They donned breathing apparatus and used hose reel jets and removed ridge tiles before getting the blaze under control by teatime, but the second floor and roof were badly damaged.
A spokeswoman for North Yorkshire Fire and Rescue Service said: "At this time we have no cause for the fire, however a fire investigation will be carried out."
Group Manager Carl Boasman said a group of staff, including auxiliary firefighters recruited to maintain the public's safety during strikes by firefighters, had been involved in an exercise in the building prior to the blaze.
He said instructors had noticed smoke was still coming from the empty building after the exercise was over, and efforts were made to tackle the fire, but firefighters had to be called in to help.
He said that although cosmetic smoke could be pumped into the buildings, fires could also be started in braziers to ensure trainees experienced heat and flames as well as smoke.
Mr Boasman added: "We've been doing this every day for 10 years and this is the first time the building's caught fire."
Measures were in place to prevent these fires setting fire to the building, and the investigation was looking into why they might have failed to work.
He did not know as yet how much it would cost to repair the roof, he added.