AT APPROXIMATELY 2:15 PM ON 9/16/2011 THIS AMBULANCE WAS TRAVELING AT 55-60 MPH IN ROUTE BACK TO THE STATION AFTER DROPPING A PATIENT AT THE HOSPITAL, THE DRIVER REPORTS THAT THERE WAS A LOAD POP!; FOLLOWED BY A HISSING SOUND UNDER THE HOOD. AS HE PROCEEDED TO MOVE TO THE SHOULDER OF THE ROAD TO INVESTIGATE THE PROBLEM THE DRIVER OBSERVED WHITE SMOKE BILLOWING OUT THE BACK OF THE UNIT. BEFORE HE COULD GET STOPPED; THE WHITE SMOKE BEGAN ENTERING THE CAB THROUGH THE AC VENTS. HE PULLED OVER AND AS HE AND HIS EMT PARTNER EXITED THE VEHICLE THE FRONT END OF THE TRUCK ERUPTED IN FLAMES!!! THIS COULD HAVE BEEN A DISASTER HAD THERE BEEN A LIFE EMERGENCY IN THE PATIENT COMPARTMENT. ON 9/19, WE HAD THE UNIT INSPECTED BY THE SHERIFF'S OFFICE FORENSIC DIVISION. DURING THE FORENSIC INSPECTION IT WAS OBSERVED THAT THE RIGHT SIDE ALTERNATOR HAD SEIZED AND BROKEN IN HALF! WHEN THIS EVENT OCCURRED IT SEVERED THE THE AC COMPRESSOR LINES AND POSSIBLY OTHER LINES WITH FLAMMABLE FLUIDS AS THERE ARE PRESSURE AND RETURN LINES FOR ALL TYPES OF FLUIDS(FUEL, BRAKE FLUID, TRANSMISSION FLUID, POWER STEERING FLUID) LOCATED IN THE IMMEDIATE VICINITY OF THE ALTERNATOR. *KB