Six fire engines and around 40 firefighters were called to a fire in a workshop on Deroy Close in Carshalton.
A single-storey workshop was destroyed by fire. One man left the property before the Brigade arrived and was treated on scene by London Ambulance Service crews after suffering from smoke inhalation.
Station Commander Jim Berry, who was at the scene, said: “The fire was in a building used as a workshop containing a large amount of wood and tools which were producing thick, black smoke.
“There were road closures in place whilst firefighters worked to gain access to the fire and bring it under control.”
The Brigade was called at 1839 and the fire was under control by 2007. Fire crews from Wallington, Sutton, Mitcham, Croydon and Purley fire stations attended the scene.
The fire is believed to have been accidental and involved a wood burner.