Firefighters rushed to a gasholder on fire in Mitcham yesterday.
Pictures and videos show smoke pouring from the scene.
Western Road in Mitcham was cordoned off after crews were first called at 8.53am on Wednesday, July 21.
Black smoke was seen billowing from a gas holder after a "small amount of solid residue" caught fire.
Four fire engines and 25 firefighters from Mitcham, Wimbledon and Tooting stations remained at the scene into the early evening, a London Fire Brigade (LFB) spokesperson said.
Residents were advised to keep windows and doors shut and a 25-meter cordon was in place.
The spokesperson added that the cause of the blaze "is not known at this time".
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