Four fire engines and 21 firefighters and officers were called to a fire at an industrial estate in Willow Lane in Mitcham.
A stack of pallets and tyres were destroyed by fire. A small part of an adjacent building facia was also damaged by fire.
A 15kg oxygen cylinder and a 96kg acetylene were involved in the fire and were cooled to an ambient temperature by crews.
The Brigade was called at 0738 and the fire was under control at 1036. Fire crews from Mitcham, Wallington and Norbury fire stations attended the scene.
The cause of the fire is under investigation.