Abstract: ON AUGUST 2, 1985, AT APPROXIMATELY 11:14 PM, AN EXPLOSION OCCURRED AT BUILDING M-75 AT THE MORTON THIOKOL PLANT IN BOX ELDER COUNTY, UTAH. THE EXACT CAUSE OF THE EXPLOSION IS NOT KNOWN, HOWEVER IT IS BELIEVED TO HAVE STARTED IN THE FINAL PRODUCT BAG HOUSE, SPREAD TO THE LARGE DRYER AND THEN TO THE DUST COLLECTION SYSTEM. THE DRYER, FINAL PRODUCT COLLECTION SYSTEM AND DUST COLLECTOR BURNED AT A HIGH SPEED, GENERATING HIGH PRESSURES AND BURSTING THESE ENCLOSED SYSTEMS. THE RESULTING FIRE DESTROYED THE INGREDIENT PREPARATION AREA AS WELL. THE PROBABLE CAUSE OF THE INCIDENT IS A STATIC DISCHARGE FROM THE MATERIALS MOVING THROUGH THE SYSTEM. THERE WERE NO INJURIES.