Abstract: On October 17, 2005, Employee #1, with Sukut Construction, Inc., was operating a John Deere 450/550 bulldozer at a construction site during a heavy thunderstorm with rain and lightning. The foreman had directed him to clear away some brush at the top of a hill, which had a slope of about 45 to 60 degrees on one side. Employee #1 was wearing a seat belt at the time. He stated that he remembers pushing some brush down the slope when the tractor started to tumble end-over-end. The tractor landed upright at the bottom of the slope. Employee #1 was able to drive to a clearing about 75 ft away, where he was found by the foreman, unconscious, lying on his back. Employee #1 had last driven this type of bulldozer about 15 years ago. He normally drove much larger equipment with different controls and handling characteristics. The foreman stated that he told Employee #1 to immediately operate the piece of equipment. No training was provided on the hazards or operation of the bulldozer, or the hazards unique to the new job assignment.