Abstract: ON A SATURDAY MORNING A GAS LEAK WAS REPORTED IN THE LOWER, END APARTMENT OF A 24 UNIT, 2 STORY BUILDING WHICH WAS IN THE PUNCH OUT STAGE OF BEING READIED FOR OCCUPANCY. A PLUMBER, EMPLOYEE #3, WAS ASKED TO CHECK OUT THE SYSTEM FOR AN LP GAS LEAK. HE USED A BOTTLE OF WINDEX TO TEST FOR LEAKS BEHIND THE KITCHEN STOVE. HE FOUND NONE. THEY THEN TURNED OFF THE MASTER GAS VALVE AT THE OUTSIDE RISER. THE PLUMBER, EMPLOYEE #3, INTENDED TO REPLACE THE METAL FLEXIBLE HOSE AND NEEDED ANOTHER WRENCH. THE ASST. SUPT., EMPLOYEE #2, WAS ON HIS WAY TO GET A WRENCH FROM THE TRUCK AND HAD JUST STEPPED OUT OF THE APARTMENT FRONT DOOR WHEN THERE WAS A TREMENDOUS EXPLOSION. HE WAS HOSPITALIZED WITH SEVERE CUTS AND BRUISES. THE PLUMBER, EMPLOYEE #3, AND THE SUPERINTENDENT, EMPLOYEE #1, WERE KILLED.