Abstract: On May 22, 2004, an employee was working on an oil well. Due to its location, the well was in a completely enclosed in the center of the building with the well in the center of the building. The well was old and is being pumped and the downhole is being serviced. On the day of the accident the hole casing needed to have additional perforations made in it. This was accomplished by lowering "perforation guns" into the hole. These consisted of nominal 4.5 inch edsteel pipes with explosive charges built into them, which are placed into the hole and fired to create new holes in the existing pipe. The pipes were delivered into the building at ground level and hoisted with overhead cranes to a conveyer about 20 feet up and conveyed to the pump deck. They were attached to the load block of the crane with a pipe clamp. The clamp was a Pipe-Co brand, Model Number S-4, pipe grab. It was designed for 4.5 inch steel tubing. However, the perforation guns were irregular in shape. As the gun was being hoisted to the well deck it slipped and fell about 18 feet, striking the employee on his left arm and the lower back of his left ankle and leg. His lower leg was broken and required subsequent surgery and 2 days hospitalization.