Four fire engines and 21 firefighters and officers were called to a fire in an industrial generator in Coldharbour Lane, Rainham.
Part of the internal casing of the generator was damaged by the fire.
The Brigade was called at 0855 and the fire was under control at 1039. Fire crews from Wennington, Barking and Dagenham fire stations attended the scene.
The cause of the fire is under investigation.