A pile of discarded cardboard boxes caught fire inside a block of flats in Tadworth last night.
Firefighters were called to the three-storey block in Chetwode Road just after 9pm, after a pile of rubbish in the first floor corridor caught alight.
Residents stood on their balconies as fire crews wearing breathing apparatus extinguished the flames.
No one was injured, but the block was left badly smoke logged.
An investigation into the cause of the fire is now underway.
Firefighter Sean Massey, from Epsom fire station, said: "It wasn't a large fire but it was still a definite life risk due to the large amount of smoke it caused.
"The fact it was in the corridor also caused problems as that is people's means of escape.
"It could have been a lot worse."