Fifteen fire engines and around 100 firefighters have been called to a fire on Ripple Road in Barking.
Firefighters are tackling a large fire impacting a two-storey building at an industrial estate.
One of the Brigade's 32m turntable ladders is at the scene helping to tackle the flames from height and also provide the Incident Commander with an aerial view to help develop tactics to bring the fire under control.
Residents are advised to avoid the area where possible, and to close their windows and doors due to the heavy smoke.
The Brigade's Control Office took the first of 15 calls at 1247 and mobilised crews from Barking, Dagenham, Ilford and other surrounding fire stations to the scene.
The cause is not known at this stage.