Twenty fire engines and around 125 firefighters were called to a warehouse fire on Fowler Road in Ilford.
Most of a two-storey, mixed-use warehouse consisting of three units was alight. There are currently no reports of any injuries.
Residents were advised to keep their windows and doors shut due to the smoke.
The Brigade's 999 Control Officers took almost 30 calls to the blaze.
The Brigade was called at 2107 and the fire was under control by 0836 (22 September). Fire crews from Romford, Dagenham, Ilford, Woodford and other fire stations in the surrounding area attended the scene.
The cause of the fire has been recorded as undetermined.