A climbing and activity centre at Crossflatts was smoke logged this afternoon when cardboard caught fire.
A crew from Keighley Fire Station used a special ventilation fan to help clear The Climbing Barn of fumes.
Firefighters were alerted at 4.40pm.
“An electric fan heater had set the cardboard alight,” said a fire service spokesman.
“Staff had put out the fire when we arrived and the building was safely evacuated.”