Abstract: During the installation of the second set of lateral drain lines in a 48-inch diameter drywell, Employee #1 and two coworkers entered into the 34-foot-long, 8-foot-deep trench to hand shovel loose soil and measure the grade. When they were ready to make the measurement, one coworker exited the trench to ensure that the detector was in alignment with the surveying laser level. As the other coworker positioned the leveling rod and detector, Employee #1 moved directly behind him. The coworkers heard a yell and when they turned to look, the south wall of the trench had caved in, completely burying Employee #1. He was removed from the trench and transported to Lake Point Hospital where he later died.