Abstract: At approximately 2:00 p.m. on June 6, 1991, Employee #1 was scraping paint from the side of a building and from some piping outside the building wall that carried anhydrous ammonia (NH3). He was working from a manlift that only traveled up and down. As the manlift descended, it struck the end of a horizontal 7 in. long by 1/2 in. diameter copper pipe. The pipe broke at the threaded connection, which allowed anhydrous ammonia at 130 psi to escape from the refrigeration system. Employee #1 sustained chemical burns on his arms and the plant was evacuated. Eleven workers were checked out at the hospital for anhydrous ammonia inhalation and were released by 4:00 p.m. the same day. Maintenance employees wearing SCBA closed two valves to shut off the escaping ammonia.