Abstract: At 12:00 p.m. on January 14, 2016, Employee #1 who was a foreman with Grabers Excavating, Inc., and employee #2 who was a laborer, were cutting and chipping an approximately 5,000 pound slab of concrete on the top of the Preliminary Treatment Structure (name of the building). This is a pre-treatment building where screening and grit removal from the wastewater influent occurs. The slab that collapsed covers the cone shaped structure where sand and grit is allowed to settle and collect. The demolition occurs so that the process will be decommissioned and replaced by a different grit removal process. Employee #1 was cutting from under the concrete slab with a concrete saw that measured 2 feet on the walls attachment and 10 inches in the center, while Employee #2 was chipping with a chipper on top of the slab while positioned off to the sides of the slab. All of a sudden employee #2 heard a crack and he fell in on top of the concrete slab that he was partially standing on, the slab collapsed on Employee #1 who was cutting with the concrete saw underneath the slab, he was crushed by the slab. Employee #1 was completely covered by the concrete slab that collapsed and was killed.