Abstract: At approximately 1:00 p.m. on September 11, 1990, Employees #1 and #2, of O'Keefe Engineering, Inc., were in an approximately 15 ft deep trench fine grading a flowline for a sewer installation. The trench had a shield that extended to approximately 3 ft from its top. Part of the top of the trench broke loose and struck the top edge of the shield, causing clumps of soil to fall. Employee #1 was struck on the head and shoulder, fracturing his collarbone; Employee #2 was struck on the back and the foot, fracturing his ankle. Both employees were transported to Western Medical Center for further treatment.