Abstract: At 10:08 a.m. on May 6, 2013, two employees opened chop gates on bottom of an overhead silo to clean /chip the hot mix build up at the silo ring. Employee #2 used a chain to wrap around the gate to secure to silo support I-Beam. The employees failed to utilize LOTO procedure by placing pin/wrench in air valve to keep constant air supply to Air Cylinder so that gate would not close. While Employee #1 stood on a 6-foot stepladder which was placed on the bed of the dump truck to perform the work, the hook on the chain and I-beam broke causing the gates to close, striking Employee #1 on the head. Employee #1 was struck by and caught between the chop gates and was killed.