One in hospital, fire at Sydney wreckers

One person has been taken to hospital following a fire and explosions at a car wrecking yard in Sydney's southwest.

Thick plumes of black smoke blanketed the sky just after 2pm on Wednesday when the blaze broke out at Canley Vale, causing the roof to give way.

Four people were rescued and treated for smoke inhalation by paramedics, including one person who was taken to Liverpool Hospital, a NSW Ambulance spokesman said.

A NSW Fire and Rescue spokeswoman said walls were threatening to collapse but the fire has been extinguished.