Abstract: Two employees were installing corrugated metal on the roof of a partially completed 15.2-meter by 42.7-meter prefabricated metal structure. The roofing material came in 0.9-meter by 9.1-meter sections. A 7200-volt overhead power line was located about 150 millimeters horizontally and 1.1 meters vertically from the edge of the roof. The employees had completed about half of the roof the previous day. As they were walking that day's first section of roofing material down the edge of the building, the material contacted the power line. The employees received electric shocks, which knocked them down and briefly rendered them unconscious. (They did not fall from the roof.) The employees sustained relatively minor burns to their hands and feet. They were transported to a nearby hospital, where they were treated and released the same day. The employees were inexperienced in hazard recognition, and one of them (employee #1) was in only his second week of this type of work.