Ten fire engines and 72 firefighters and officers were called to a fire at a skate park in Upper Rainham Road in Hornchurch.
A number of wooden outbuildings were destroyed by the fire and crews removed and cooled a propane cylinder to an ambient temperature, as cylinders can explode when exposed to heat.
There were no reports of any injuries.
Station Manager Robbie Robertson, who was at the scene, said: "Crews worked hard to stop the fire spreading to the main skate park area and building, which have not been affected by the fire."
The Brigade was called at 0354 and the fire was under control at 0541. Fire crews from Hornchurch, Dagenham, Romford, Harold Hill, Ilford and surrounding fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.