Four fire engines and 21 firefighters and officers were called to a fire in a car repair workshop in Mount Pleasant, Wembley.
A single storey garage was slightly damaged in the blaze.
One man had left the property before the arrival of the Brigade and was treated on the scene for smoke inhalation by London Ambulance Service before being taken to hospital.
The Brigade was called at 1642 and the fire was under control at 1939. Fire crews from Park Royal, Acton, Willesden and Ealing fire stations attended the scene.
The cause of the fire is under investigation.