AFTER VEHICLE WAS VACUUMED IT WOULD NOT START; THE VEHICLE WAS PUSHED TO THE SIDE AND THE DRIVER TURNED THE KEY AGAIN TO START IT, AND A PUFF OF SMOKE CAME FROM THE STEERING COLUMN. THE DRIVER QUICKLY TRIED TO TURN THE KEY TO THE OFF POSITION,THEN THE LIGHTS DIMMED. THE KEY BECAME IMMOVABLE IN THE START POSITION, AND SMOKE BEGAN TO POUR FROM ALL THE VENTS. STUNNED, THE DRIVER OPENED THE DOOR TO RUN FROM THE VEHICLE, BUT THE AIR BAG DEPLOYED AND KNOCKED THE DRIVER UNCONSCIOUS. THE DRIVER WAS PULLED FROM THE VEHICLE AND REVIVED IN TIME TO GET THE NEGATIVE BATTERY TERMINAL DISCONNECTED. EMS ATTENDED TO THE DRIVER'S INJURIES.