Ten fire engines and around 70 firefighters were called to a fire on Eleanor Street in Bow.
A railway arch and part of a mezzanine floor being used for manufacturing were badly damaged by the fire. One man left the building before the Brigade arrived and was assessed at the scene by London Ambulance Service crews.
The Brigade was called at 1035 and the fire was under control by 1424. Fire crews from Shadwell, Bethnal Green, Whitechapel, Poplar and surrounding fire stations were at the scene.
The cause of the fire has been recorded as undetermined.