Abstract: ON JANUARY 24, 1985, AT 3:50 PM, DURING STAND BY FOR START UP OPERATIONS AT THE DEWAX AND DEASPHALT (D & D) UNIT, A 3 INCH PIPE RUPTURED WHILE PROPANE (UNDER APPROXIMATELY 100 - 150 POUNDS OF PRESSURE) WAS BEING CIRCULATED. THE RUPTURE WAS LOCATED IN THE VICINITY OF DD 8 (A COLD C3 SURGE VESSEL). THE LIQUID PROPANE DISCHARGED INTO THE IMMEDIATE AREA, CREATING A DENSE CLOUD ABOUT 5 FEET HIGH. THE D & D UNIT EMPLOYEES COULD NOT LOCATE THE SOURCE OF THE LEAK BECAUSE OF THE DENSE PROPANE CLOUD. THE CLOUD WAS BLOWN TO THE EAST BY A 10 TO 15 KNOT WIND. THE TEMPERATURE WAS APPROXIMATELY 35 DEGREES. THE PROPANE CLOUD CAME IN CONTACT WITH THE PILOT LIGHTS OF THE DEASPHALT UNIT. THE PROPANE IGNITED, FLASHED BACK TO THE SOURCE, AND EXPLODED. A SECONDARY FIRE AND EXPLOSION OCCURRED AT THE ADJACENT COMPRESSOR FILTER BUILDING AND ROTATING DISK CONTACTORS (RDC) VESSEL. A TOTAL OF 19 EMPLOYEES RECEIVED MEDICAL TREATMENT, RANGING FROM PROLONGED HOSPITALIZATION FOR BURNS TO FIRST AID FOR CUTS, BRUISES AND RINGING EARS. ONE EMPLOYEE WAS KILLED. SEVEN OF THE EMPLOYEES WORKED IN THE D & D UNIT. OF THE SEVEN, ONE WAS KILLED AND SIX HOSPITALIZED. THE REMAINING 13 EMPLOYEES WORKED IN NEARBY UNITS. THEY RECEIVED FIRST AID TREATMENT AND WERE RELEASED.