LPG tanker crash causes major traffic woes in Sydney's west

Hours after a 40,000-litre LPG tanker slammed into a car and rolled in Sydney’s west, motorists are still being advised to brace for traffic chaos.

A 26-year-old p-plater was trapped for more than half an hour and suffered leg and facial injuries after the Cootes tanker crushed her car on the Great Western Highway at Werrington, near the University of Western Sydney campus, about 10am.

Crash investigators said she was lucky to escape alive as they established a 900m exclusion zone around the crash site.

Firefighters hosed down the tanker as it was drained of fuel.

The Great Western Highway remains closed between O'Connell Street and Werrington Road, Werrington. Diversions remain in place this evening and the Transport Management Centre has advised motorists to avoid the area.

Emergency services remain at the scene as police investigate the crash.

They believe the tanker was heading west when it veered onto the wrong side of the road and slammed into the car.

Tanker company Cootes was the subject of a major crackdown following a fatal crash in Mona Vale two years ago. The company was fined more than half a million dollars and several vehicles were grounded.

Cootes has told 9NEWS the tanker involved in today’s crash passed an internal vehicle inspection within the past five days.