Abstract: Employee #1 was instructed to remove old sinks and toilets from a bathroom and then to knock down the concrete block walls in the bathroom area. He climbed a wooden stepladder, stepped onto a high concrete block wall, and walked along a short section to a 2 ft wide by 8 ft long platform atop the walls. He climbed down into one of the bathrooms and had just begun to work when the lights in the area went out. The foreman told Employee #1 to stay where he was until he reconnected the light's extension cord. For some reason, Employee #1 climbed back on top of the wall and was walking in the dark when he slipped and fell into an approximately 1 1/2 ft wide by 3 1/2 to 4 ft deep opening and became wedged between the walls. Coworkers heard him yell and removed him from between the walls. Employee #1 was transported to a shock/trauma center, where he was treated for a bruised back, neck, and ribs, and then released. Employee #1 disobeyed the foreman's request to stay in his work area until lighting was restored.