Abstract: At approximately 11:30 a.m. on October 8, 1985, Employees #1 and #2 were in a 28-ft-long,-7-ft-wide, and approximately 8-ft-deep tank hole trench that had vertical sides and no shoring. They were taking exact measurements of the bottom for installation of a 24-ft-long by 5-ft-diameter oil storage tank. An existing storage tank was approximately 4 ft away from the south side . The employees had been in the tank for a short time when Employee #2 saw out of the corner of his eye that the south side of the trench was starting to collapse. He shouted and both employees ran to the northeast corner, where they were pinned waist deep by the falling dirt. Employee #1 suffered a broken pelvis along with various contusions and abrasions. Employee #2 suffered a broken lower right leg with nerve damage and ligament damage to the knee. Both employees were hospitalized.