Police and fire crews attended a deliberate flat fire in the Glenshesk Park, Portrush shortly after 5.30am this morning.
Two fire appliances from Portrush Fire Station and one fire appliance from Portstewart Fire Station attended the scene.
A NIFRS spokesperson said "Firefighters wearing breathing apparatus, used 2 hose reels to extinguish the fire. One casualty was treated at the scene by the Northern Ireland Ambulance Service.
"The incident was dealt with by 6.14am and the cause of the fire is being treated as deliberate ignition."