Ten fire engines and around 70 firefighters were called to a flat fire on Brunel Street in Newham.
Firefighters tackled a blaze within a three roomed flat on the second floor of a eleven-storey building, which is currently under construction. A significant part of the flat was damaged by the fire, no injuries were reported.
Around 200 construction workers left the building and around 400 workers left surrounding construction sites before the Brigade arrived.
The Brigade was called at 1316 and the fire was under control by 1434. Fire crews from Plaistow, Stratford, Millwall, Shadwell, Hornchurch, Greenwich and other surrounding fire stations attended the scene.
The Brigade's Fire Investigators believe the cause of the fire involved the unsafe disposal of smoking materials.