Six fire engines and around 40 firefighters were called to a fire at a vehicle workshop on Crow Lane in Romford.
Half of two single-storey industrial units were damaged by the blaze. Ten people left the property and there were no reports of any injuries.
The Brigade was called at 1806 and the fire was under control by 1945. Fire crews from Dagenham, Ilford, Wennington, Hornchurch, Homerton, and Walthamstow fire stations attended the scene.
The cause of the fire is under investigation.