More than 200 firefighters are tackling a blaze which is said to be the biggest in London for several years.
Forty fire engines have been sent to the incident at a recycling centre on Chequers Lane in Dagenham, east London, about eight miles from the Olympic Park.
London Fire Commissioner Ron Dobson said: "We’ve not seen a fire of this size in London for several years. It's certainly a dramatic end to the Olympics for the London Fire Brigade.
"That said though, we are still able to attend incidents across the capital and the fire cover we’re providing at the Olympic venues has not been affected.
"Fortunately, we have not had any reports of injuries at this stage."