Four fire engines and around 25 firefighters were called to a fire at a factory and office on Thames Road in Barking.
A single storey factory and office were partly damaged by fire. There were no reported injuries.
The Brigade was called at 0509 and the fire was under control by 0707. Fire crews from Barking, East Ham and Plaistow fire stations attended the scene.
The cause of the fire is under investigation.