Twenty fire engines and around 125 firefighters were called to a grass fire behind Clemence Road in Dagenham.
Firefighters tackled a fire of around eight hectares of grass, shrubland and trees, as well as fences and garden furniture. Nearby properties were temporarily evacuated as a precaution. Three people were treated on scene by London Ambulance Service for smoke inhalation, with one taken to hospital.
Group Commander Matt Hayward said: "Firefighters worked extremely hard to prevent the fire from spreading to nearby properties.
"The fire had reached some garden fences, sheds and garden furniture. As well as our jets, we used wildfire beaters to beat the flames and stop them from reaching the properties.
"We also thank Barking and Dagenham Council who had put fire breaks in place, which helped stop the fire from reaching the properties. We also had great support from our blue light colleagues, Essex Fire and Rescue Service and the London Ambulance Service Hazardous Area Response Team.
"Firefighters will remain at the scene for the next few hours to continue to dampen down the surrounding area."
A wildfire response vehicle was deployed to the incident. These vehicles provide off-road capability enabling the transportation of additional equipment closer to fires on open ground. Each vehicle carries approximately 475 litres of water, a backpack blower, ear defenders, beaters and misting lance technology, which allows firefighters to pump water and drive, enabling them to tackle grass fires more quickly and safely. The Brigade is currently trialling four wildfire response vehicles across the capital.
Wildfire support officers, with enhanced training to tackle wildfires, were also deployed, providing tactical advice to the Incident Commander. The drone team also attended providing the Incident Commander with a greater situational awareness of the fire.
The Brigade's Control Office took the first of over 75 calls at 1830 and the fire was under control by 2146. Fire crews from Dagenham, Hornchurch, Wennington, Romford and other surrounding fire stations attended the scene.
The cause of the fire is under investigation.