An employee was working from a walk board (placed on top of rafters), installing hangers for a sprinkler system inside a cooling tower. He was wearing a harness with a retractable lanyard at the time. As he was turning around to talk to his coworker, the walk board shifted and he fell about 6 to 8 feet, ultimately hanging by his harness about 40 feet above the base of the cooling tower. He was hospitalized with a laceration, soft tissue damage, and a blood clot to his left arm.