Abstract: At approximately 2:45 p.m. on June 3, 2013, Employee #1, a crane rigger, was disassembling and moving a drilling rig to another location. The employee attempted to attach a chain sling to the ball hook on the whip line of the crawler crane. Employee #1 was not able to place the chain sling master link on the crane hook and the sling fell to the rig sub-structure floor and started to slide off the edge of the rig. The employee stepped on the chain sling to prevent it from falling off the rig. The sliding chain caused the employee to lose his balance and he fell 25 ft to the ground. Employee #1 was wearing a full body harness with an attached lanyard, but was not tied-off to an anchorage. The employee was pronounced dead at the scene.