Eight fire engines and around 60 firefighters were called to a fire at a metal scrapyard in an industrial estate on Perry Road, Dagenham.
Station Manager Mark Jordan, who was at the scene, said: "A large pile of scrap waste was destroyed by fire and crews worked hard to ensure the fire didn't spread to any other part of the industrial estate. While it caused a lot of smoke, the site isn't close to any residential areas."
Local road closures are still in place.
The Brigade was called at 0308 and the fire was under control at 0616. Fire crews from Barking, Dagenham, East Ham, Wennington and surrounding areas fire stations attended the scene.
The cause of the fire is under investigation.