Nearly 300 homes have been evacuated amid fears of an explosion after a suspected arson attack on a garage containing several gas cylinders.
Firefighters were called late on Tuesday night to the blaze in Amity Road in Reading, Berkshire.
Some families were taken to South Reading Leisure centre for the night.
Police warn of severe delays as busy London Road is closed. The emergency services will be on the scene for most of the day, police say.
No-one was hurt in the fire, which broke out at 2240 BST in a garage on an industrial unit on Amity Road, near London Road.
People living in Amity Road, Regent Street, Cholmeley Terrace, Cholmeley Place, and parts of London Road had to leave their homes, with those with nowhere else to go looked after in the Granby pub before being taken to the emergency rest centre.
Reading area commander Chief Supt David Murray said: "We are investigating the possibility that this was an arson following a break-in at the garage unit overnight, and I would urge anyone with information to contact police immediately."