Update, 7pm: Canning Vale residents were being warned of dangerous smoke this afternoon after a building fire on Nicholson Road.
The fire at Nuplex Composites, a company which manufactures fibre glass and resins, caused a chemical spill and resulted in several closures on Roe Highway.
All roads on the highway and surrounding the fire scene have been reopened but heavy delays extended into this evening.
The Department of Fire and Emergency Services was called to the fire at about 3.35pm and seven fire trucks and 30 firefighers attended the scene.
The blaze is contained and under control and 28 firefighters from seven brigades will remain on the scene into the night. The cause of the fire is still being investigated.
Dangerous smoke prompted an alert to be issued for people in Langford, Lynwood, Canning Vale, Thornlie, Parkwood and Beckenham.
People in the area were urged to stay inside with doors and windows closed and switch air-conditioners off this afternoon. However, DFES says they are no longer being affected by the smoke.
People at the Whaleback Golf Course were evacuated this afternoon.
Motorists are still being encouraged to avoid the area and be aware of emergency personel working in the area.
[img:15796689|caption=Fire crews at Canning Vale. Picture: Liam Croy/The West Australian]]