Abstract: At approximately 10:00 a.m. on January 22, 1996, Employee #1, of Exsil, Inc., San Jose, CA, was on the manufacturing floor setting up an Allen Bradley-Speed lapping machine. He had been assigned to polish a wafer run, and pushed up the lapping machine's carrier head so it would engage the ring gear. The guard on the machine is designed to prevent the machine from working unless the operator simultaneously pushes the START button and disengages the safety latch. Employee #1 had not disengaged the safety latch when the carrier head dropped, landing on his right hand and amputated 1/4 in. from his middle finger. He was admitted to Kaiser Hospital and released on January 25, 1996. Subsequent investigation showed the safety latch to be functioning properly. The lapping head was raised and lowered by an air cylinder; on inspection, it was revealed that three of the four bolts that attach the lapping head to the air cylinder had failed, and this caused the head to drop. The employer had no records showing that the equipment had been inspected periodically, but the manufacturer's manual indicated that the bolts needed no inspection or maintenance. Also, the bolts were recessed into the lapping head, which would have made an inspection difficult. Employee #1 had been trained on the lapping machine eight months to one year prior to his accident, and was a qualified operator.