A vast warehouse blaze is being tackled by around 100 firefighters, emergency services said.
Smoke darkened miles of the east London skyline as it rose from the fire on Chequers Lane, Dagenham, on Saturday evening, the London Fire Brigade (LFB) said.
Some 15 fire engines had been sent to the site shortly before 6pm, where flames had raged through mixed waste.
Station Manager Gary Woulds said: "Crews are working extremely hard to get the fire under control.
"It is currently affecting a single storey warehouse containing approximately 100 tonnes of mixed waste and machinery.
"Around half of the warehouse is alight."
LFB added on its Twitter feed that the blaze was a "protracted incident" and officers were likely to be on the scene "for some time".
There were no reported injuries, the London Ambulance Service said.