Abstract: On August 6, 2008, Employee #1, a laborer, and a coworker, an equipment operator, were directed to uncover an existing 3-ft diameter clay pipe, and cut the pipe so that a new part of the water treatment plant could tie into the pipe. The pipe was uncovered and the excavator was used to lower a pipe cutter into a 4-ft excavation. The coworker got off of the excavator, the Kobelco MD320B, and left the excavator running. He was assisting Employee #1 to set up the pipe cutter in the excavation. Then he left the excavation and went to the cab to retrieve a rag to wipe off hydraulic lines. The coworker reached behind the seat with his back to the steering wheel when he heard Employee #1's loudly scream. The coworker noticed that his safety vest was caught on the operating joystick and that the boom of the excavator moved, striking Employee #1, who was on the ground. The coworker turned back around and moved the bucket, and boom of the excavator away from Employee #1. Employee #1 fractured his hip and was hospitalized for fifteen days. The excavator operating controls were activated while in the "off" position because the control lever lock was defective.