Abstract: At 12:00 p.m. on June 15, 2015, Employee #1, a utility laborer, was working alone on the fifth level of the C and D building. Employee #1's job was to ensure that conveyor belts carrying electric arc furnace (EAF) dust were continuously running and maintained as unclogged. The utility laborers shovel and air lance the rollers under the conveyor belt to keep the belt from clogging, allowing the belt to keep EAF dust moving into one of four silos and to redirect the flow as needed so that the silos never overflow. At the end of the conveyor belt there is a nine inch lip off the floor which has an opening that leads into Silo Number 4. The opening is 37.25 inches in length and 15.5 inches in width. The utility laborers do have to stand near the opening to take measurements of the EAF dust inside the silo to determine if they should redirect the EAF dust into another silo to prevent overfilling. There are no other openings or access points to Silo Number4 from the fifth level of the C and D building. At one point, Employee #1 fell through the opening into Silo Number 4 which was partially filled with EAF dust material. A crane operator, a coworker, unable to feed material onto the conveyor belts which had stopped, attempted to contact Employee #1 by radio. When Employee #1 could not be reached by radio, the coworker and superintendent went to the fifth level of the C and D building and found Employee #1 in Silo Number 4 when they looked through the opening. The local fire department was contacted. Maintenance workers used a reciprocating saw to cut the bottom of Silo Number 4 to gain access. Fire department personnel retrieved Employee #1 out of Silo Number 4 without entering the silo. Employee #1 was transferred to the hospital where he was pronounced dead. Employee #1 was killed from asphyxiation/suffocation due to aspiration of foreign material.