Abstract: After installing windows in a new single family home, Employee #1 was instructed to cut out the overhangs on the first floor for the future fireplace. The entire wooden flooring was in place on that floor. Employee #1 kneeled to mark the location where the fireplace would come through the floor. He then cut a 28 1/2 in. wide by 68 in. long section out of the wood flooring using a power hand saw. As Employee #1 started to get up from kneeling, his hard hat slipped off his head and started to fall. Instinctively, he took one step to try to catch the hat but lost his balance. His right foot slipped into the hole that he had just cut and he fell through to the concrete basement floor. Employee #1 was treated and taken to shock trauma. He suffered two cracked vertebrae on the right side of his back as well as severe bruises.