Abstract: At approximately 9:30 a.m. on January 4, 2011, Employee #1, Employee #2 and a coworker were assigned to work in a trench 5 feet, 1 inch wide by 24 feet, 2 inches long by 62 inches below the finished grade. A support system was not used to protect employees from possible collapse. Their assignment was to replace the improperly installed plastic conduit with new metal conduit. In order to remove the existing conduit, the process required the employees to each operate pneumatic jack hammers while lying on their backs in order to remove the concrete duct bank that encased the conduit. The coworker's jack hammer was not working properly. So he left the trench to replace the jackhammer. Employee #1 and Employee #2 continued their work of jack hammering. At that time, a section of the concrete duct bank became displaced and fell on both Employee #1 and Employee #2, pinning and killing Employee #1 while injuring and entrapping Employee #2 who was rescued and flown to the Lehigh Valley Trauma Center. Employee #2 was treated and survived the accident.