Abstract: On January 2, 1986, employees were digging a trench to install an 8-in.steel pipe gas line. Employee #1 was working as a grade-man to support the backhoe operator. The employee was responsible for the depth of the trench and keeping the bottom of the trench level. The backhoe operator had just uncovered a water line house tap. When Employee #1 entered the trench to dig out the area around the water line, the right trench wall caved in, burying Employee #1 to the waist. The trench was approximately 2.5-ft wide by 6-ft deep and about 40-ft long at the time of the accident. The trench soil consisted of fill dirt and shale. No shoring was installed in the area of the trench where the cave-in occurred. Employee #1 was hospitalized with injuries to the right knee, consisting of pulled ligaments, torn cartilage, and a fractured bone.