Four fire engines and around 25 firefighters were called to a fire at a house in Havelock Road in Southall.
Half of the ground floor of an end of terrace house was damaged by the fire. Five men were treated at the scene by London Ambulance Service crews.
The Brigade was called at 0843 and the fire was under control at 0921. Fire crews from Southall and Heston fire stations attended the scene.
The cause of the fire is believed to have been an electrical event in a fridge freezer.