Abstract: On February 17, 2016, at approximately 3:22 PM, Employee #1 was walking from section "J" to section "K" eastward on top of a mezzanine floor, approximately 21 feet above ground. Employee #1 was counting the ductwork that needed additional fabrication (punch-list items) completed prior to the next phase of the inspection. Employee #1 was walking backwards counting the ductwork heading east when he fell through a floor opening in the mezzanine. The floor opening was 40 inches wide by 10 feet long. The floor opening was located within an area approximately 30 feet by 30 feet with red caution tape approximately 3.5 feet high around four (4) steel beams. The floor opening was located on the west side, directly in line with the red caution tape. Employee #1 sustained a closed head trauma with extensive calvaria and basilar skull fractures secondary to a fall from height resulting in his death.