Twenty residents escape Sydney unit fire

Twenty people have escaped a burning unit block in Sydney's west.

Thick black smoke was billowing from the three-level Granville building when fire crews arrived after 9am on Thursday.

Everyone inside managed to get out, with one person treated at the scene for smoke inhalation before being taken to hospital, a Fire and Rescue NSW spokesman told AAP.

The blaze has been brought under control but crews remain on scene.