Abstract: At approximately 1:04 p.m. December 24, 2005, Employees #1 and #2, and two coworkers were removing a section of floor on the thirty-third floor of a building using a concrete cutting saw, a hand saw, and a jack hammer to cut the concrete and chip it for removal. At first, several small cylinder-shaped holes were cut to see how far the concrete cutting saw blade needed to be adjusted to avoid cutting the metal floor decking. When the two coworkers assigned to saw-cut the concrete slab were almost finished, Employees #1 and #2 began to jack-hammer the concrete to break it up. After a few minutes, the floor slab fell, and the employees fell with the slab to the floor below. Employee #1 was struck on his right hand and shoulder by a piece of concrete and suffered an amputation of his right arm. He was hospitalized with his injury. Employee #2 was treated in the hospital and was released the same day. The investigation revealed that, according to the employer, a pretask demolition plan was communicated verbally to employees. However, a written demolition plan was not provided. It appears that setting up the saw blade to cut the concrete, and readjustment of the depth of blade to the top of the metal plate, were not well communicated. In addition, there was no discussion about fall protection and the possibility of fall exposures.