Fire broke out just before 10am this morning at the Swimart Pools and Spas building in Warners Bay on Hillsborough Road.
Fire and ambulance crews attended the blaze following reports it had started when a forklift caught alight.
Fire crews successfully extinguished the fire, and are now at work ventilating smoke from the building.
Two occupants of the building were treated for minor smoke inhalation at the scene.