Abstract: At approximately 6:00 p.m. on April 3, 2012, Employee #1 was working for a plumbing, heating, and air conditioning contractor. The incident occurred at a retail store distribution warehouse. Employee #1 was a full-time permanent employee of the employer. He was not an employee of the retail distribution center. Employee #1 was conducting the startup procedures for a roof-mounted condenser unit. He was on the west side of the condenser unit. The condenser unit was 89 inches (2.26 meters) east of a skylight that was covered with acrylic plastic such as Plexiglas. According to a witness, Employee #1 was facing east and talking on his cell phone. He stood up and took a step or two backwards. He then appeared to stumble or trip on his foot and fall backwards onto the skylight, breaking the acrylic plastic or Plexiglas cover. He fell approximately 39 feet (11.9 meters) to the concrete floor below. Employee #1 received blunt force trauma injuries to multiple parts of his body, and he was killed. The causal factors were that employee #1 was not wearing a fall protection device that was appropriately secured, and that the skylight was not guarded or protected.