Abstract: At approximately 2:00 p.m. on November 6, 2000, Employee #1 watched as two coworkers aligned the second section of a manhole with the base. The coworkers were in a straight-walled trench that ran 34 ft north to south and 28 ft east to west. In the section where they were situated, the trench as approximately 9 ft wide and 9 ft 10 in. deep. When Employee #1 saw that his coworkers were having difficulty, he entered the trench to help them. While they were concentrating on the alignment, soil began to slough off from underneath a concrete slab that formed a section of the sidewalk running adjacent to the east side of the trench. This undermined the area under the concrete slab, which became dislodged and flipped across the trench, striking Employee #1. He was crushed against the manhole and was killed.