Abstract: EMPLOYEES #1 THROUGH #6 WERE PREPARING A LARGE REFORMER FURNACE FOR FIRING UP. THE FURNACE HAD BEEN SHUT DOWN FOR ABOUT 5 MONTHS. BECAUSE THERE WAS A LACK OF COMMUNICATION BETWEEN THE WORKERS, AND BECAUSE SOME OF THE EMPLOYEES WERE NOT FAMILIAR WITH THE FURNACE OPERATOR'S MANUAL, THE FURNACE WAS LIT WHILE 10 MANUALLY OPERATED GAS VALVES WERE OPEN. THE FLAME IGNITED THE GAS WHICH HAD BUILT UP IN THE FURNACE, CAUSING AN EXPLOSION. THE PROPER PROCEDURE IS TO OPEN THE VALVE ON EACH BURNER, AND LIGHT EACH BURNER, SEPARATELY. ALSO, A FIVE MINUTE PRESSURE TEST IS CALLED FOR TO DETECT ANY LEAKS IN THE SYSTEM. THE EXPLOSION PROBABLY WOULD HAVE BEEN PREVENTED IF THE PRESSURE TEST HAD BEEN RUN.