Abstract: Employees #1 and #2 were installing 10 ft long sections of 8 in. sewer pipe in a 15 ft deep trench. They had stepped approximately 8 ft out of the trench box to do a grade check with a laser beam when one of the vertical walls of the trench suddenly collapsed. Both employees (who were wearing hard hats) were thrown against the opposite wall and covered with dirt. Employee #2 was buried to his head and easily rescued; he suffered scrapes and bruises. Employee #1 was buried under approximately 2 ft of dirt for 4 to 6 minutes. Nearby rescue personnel restored his breathing. He was hospitalized with a fractured jaw and bruises. Factors contributing to the accident included: three preceding days of melting snow; vibrations from heavy equipment on an adjacent roadway; improper location of the spoil banks; and the improper use of a trench box, which was being used instead of shoring or sloping.