Abstract: NINE 20 BY 13 FOOT CEMENT SLABS HAD BEEN TEMPORARILY EMPLACED AS WALLS FOR A SILAGE PIT UNDER CONSTRUCTION. THE OWNER OF THE CONSTRUCTION COMPANY INSTRUCTED THE OPERATOR OF A D-6 CAT DOZER NOT TO BACKFILL BEHIND THE SLABS UNTIL BRACING HAD BEEN INSTALLED. APPARENTLY THE DOZER OPERATOR MISUNDERSTOOD THE OWNER AND PROCEEDED TO BACKFILL THE SPACE BETWEEN THE SLABS AND EARTH WALL. THE PRESSURE ON THE BACKSIDE OF THE SLABS CAUSED ONE TO FALL INWARDS. SINCE THE SLABS HAD BEEN TIED TOGETHER AT THE TOP BY A WELD, ALL THE SLABS FELL IN DOMINO FASHION. EMPLOYEE #1, WHO WAS STANDING AT THE PASSENGER SIDE OF THE WELDING TRUCK GETTING A DRINK OF WATER, WAS STRUCK IN THE ARM BY THE FALLING SLAB, CAUSING HIS ARM TO BE PINNED AGAINST THE WELDING TRUCK. EMPLOYEE #2, WHO WAS OPERATING A CRANE, WAS STRUCK IN THE HEAD BY A FLYING WOODEN "A" FRAME LAUNCHED BY ANOTHER FALLING SLAB. BOTH EMPLOYEES WERE HOSPITALIZED.