VEHICLE REAR ENDED ANOTHER VEHICLE AT 50MPH AND THE PASSENGER SIDE AIRBAG DID NOT DEPLOY. THE DRIVER'S SIDE AIRBAG DEPLOYED IMPROPERLY, AND KNOCKED DRIVER'S HEAD THROUGH SIDE WINDOW. GAS FROM THE AIRBAG IGNITED A FIRE ON THE DRIVER'S SWEAT SHIRT. MANUFACTURER SAID THERE WAS NO PROBLEM. *AK