Abstract: On March 24, 1995, Employee #1 and a coworker, both of Batterton Waterproofing Inc., were working on the interior of a multi-bin concrete grain silo at Gowrie, IA. The bin was triangular, measuring 11 ft by 11 ft by 14 ft, with an effective depth of 126.3 ft. The employees were driving steel pins with a powder actuated driver and drilling 3/4 in. diameter holes with an electric hammer drill into the concrete sidewalls in preparation for gunite application. The employees entered the bin at approximately 7:30 a.m. and rode the powered scaffold close to the top of the bin. The scaffold was supported by three 5/16 in. wire ropes and consisted of three HiLo D-800 units with a triangular platform constructed from six 2 in. by 12 in. by 8 ft planks and 1/2 in. plywood, without a guardrail on the side where work was performed. They performed the drilling and driving operations. At approximately 8:00 a.m. they were ready to descend to the next work level. While descending, a wire cable came out of a pulley, causing one corner of the platform to drop about 3 ft. Employee #1 was operating one power unit from outside the perimeter of the guardrail. The coworker was operating two of the power units with his back toward Employee #1. Neither employee was wearing fall protection. The coworker grabbed onto the HiLo scaffold unit to his right to prevent his falling. Employee #1 fell approximately 100 ft to the sloping concrete bin floor and then another 10 feet through the access hole. He died.