A 19-YEAR-OLD man is fighting for life after suffering burns to his head, torso, arms and hands in a fire at a single-storey automotive workshop in Perth.

St John Ambulance said the man was rushed to Fiona Stanley Hospital as a priority one patient after being burned in the blaze at Precision Automatic Transmissions on Ruse Street, at the intersection of Hutton Street, at 12.22pm.

A hospital spokeswoman said the man was in a critical condition.

A second man received superficial burns to his arm and did not need hospital treatment.

Camera Icon Fire crews at the scene. Credit: Oscar Ward/The West Australian

St John Ambulance said there were initial fears others may have been trapped during the fire but a search has since been conducted and no one else was inside the building.

A witness said they heard an explosion while fleeing the fire scene.

Camera Icon The fire is creating a huge smoke plume over Osborne Park. Credit: Neale Prior/The West Australian

Several crews are working to put out the blaze which is contained and controlled but not yet fully extinguished.

The Department of Fire and Emergency Services has urged people in the area to stay inside, out of the smoke or fumes, with doors and windows closed.

The ChemCentre and the Department of Environment and Regulation Pollution Response Unit are providing technical support to DFES.

Some roads may be closed and motorists are urged to avoid the area, reduce speed and be aware of emergency services personnel.