Abstract: ON JULY 1, 1985, EMPLOYEE #1 DETECTED A PIN HOLE LEAK IN A 5000 PSI HYDROGEN GAS LINE WELD AT A SLIP JOINT. HE WROTE UP A WORK ORDER TO REPAIR THE LEAK, BUT THE COMPANY OPTED TO WAIT UNTIL JULY 8 TO BEGIN REPAIRS. TWO DAYS BEFORE THE LEAK WAS DUE TO BE REPAIRED, ON JULY 6, THE WELD AT THE JOINT CAME APART, RESULTING IN AN EXPLOSION WHICH SENT BUILDING PIECES AND EQUIPMENT FLYING IN ALL DIRECTIONS. THE POSSIBLE IGNITION SOURCES ARE EITHER FRICTION OR PIPES SLAMMING INTO THE STEEL I-BEAM NEXT TO THE GAS LINE PIPE. BEFORE THE EXPLOSION OCCURRED, EMPLOYEE #2 HAD SMELLED AMMONIA. HE THEN DISCOVERED A LARGE CLOUD OF AMMONIA GAS ON THE FLOOR OF THE COMPRESSOR ROOM AND PROCEEDED TO EVACUATE THE BUILDING. HE WAS ABOUT 40 FEET FROM THE BUILDING WHEN THE EXPLOSION OCCURRED. EMPLOYEES #3,4,5, AND 6 WERE IN THE CONTROL ROOM WHICH IS ADJACENT TO THE COMPRESSOR HOUSE AND EMPLOYEE #8 WAS IN THE ACID PLANT SOME 100 FEET AWAY.