Abstract: A THREE MAN CONSTRUCTION CREW WAS SETTING PREFABRICATED ROOF TRUSSES OVER THE OFFICE AND SUPPORT AREA OF A 128 BED NURSING HOME UNDER CONSTRUCTION. THE FIRST TRUSS WAS BRACED TO STEEL AND THE CONCRETE FLOOR BY A PIECE OF 2 BY 4. THE SUCCEEDING TRUSSES WERE BRACED BY TWO 2 BY 4S ACROSS THE BOTTOM OF THE TRUSSES, TWO 1 BY 3S ACROSS THE TOP OF THE TRUSSES AND ONE 1 BY 3 HORIZONTALLY ACROSS THE VERTICAL END PIECE. DIAGONAL BRACES WERE NOT USED, AND ONLY ONE NAIL WAS USED TO CONNECT THE BRACING TO THE TRUSSES. THE TRUSSES SUDDENLY FELL OVER, STARTING WITH THE FIRST, WHICH KNOCKED ALL THE OTHERS DOWN IN TURN. EMPLOYEE #1 RECEIVED BRUISED RIBS, A BRUISED SPLEEN AND POSSIBLE PINCHED NERVES IN HIS NECK AND SHOULDER WHEN HE FELL ALONG WITH THE TRUSSES. HE WAS HOSPITALIZED. THE ACCIDENT WAS CAUSED BY THE IMPROPER TRUSS BRACING USED BY THE WORK CREW.