Abstract: Employee #1 and a coworker were working on an underground pipeline project. They were using hand-held, portable, gasoline-powered Stihl masonry saws, model TS 760 AV, to cut concrete pavement. At the same time, a Ford l-9000 tri-axle tandem dump truck was backing up to pick up material being excavated by pipeline. The driver saw the coworker but not Employee #1, whose back was toward the dump truck and who was in a crouched position, unaware of the backing truck. Employee #1 was run over by the right rear and front tires of the truck, and was killed. The coworker stated that he did not see or hear the backing truck. The truck's back-up alarm was working, but the combined sound of both masonry saws was apparently greater than the sound intensity of the back-up alarm. This accident might have been avoided if the employers of the truck driver or of Employee #1 had complied with 29 CFR 1926.602(a)(9) and/or 29 CFR1926.201(a)(1).