Abstract: Employee #1 was attempting to return to ground level from a measuring point for midspan joist blocks. As he walked on the ground floor joists, he mis-stepped and his right foot slid between the joists and inside the cement wall of the foundation, causing him to fall forward. To avoid hitting a corner of the rim joist as he fell, Employee #1 attempted to jump off his left foot. He landed on the rim joist corner, sustaining acute contusions to his left rib cage and spleen. Employee #1 was hospitalized at St. Charles Medical Center, Bend, OR, for five days. He is expected to remain off work for two weeks. The investigation revealed that the top of the floor joist was 19 in. above the ground and the joists were placed 2 ft apart on centers.