Abstract: At approximately 1:49 a.m. on September 5, 2000, Employee #1 was working on the K-1 fixture at the Ford line, the start of the frame assembly for a pickup truck. He was relieving a coworker who had been operating the fixture at the northeast corner, and he was one of four employees to operate this machine. The workers installed rivets and crossmembers at key locations in the frame. After each worker installed approximately four rivets, they would retreat to a palm button station at each corner of the machine. Each station incorporated two palm buttons and a red stop button; three of the four employees had to depress their buttons and hold them in while the fourth operator depressed his buttons and became the trigger man. When the fourth employee depressed his buttons, the circuit was closed and a gantry crane on a monorail was signaled to descend and grasp the steel frame with four claws and carry it to another position to be worked on. The area around the truck frame was partially protected by a light curtain that angled away from the frame table. After Employee #1's coworker returned to the K-1 fixture, he stepped up on to the work platform and put on his left glove first. The operator at the north-west corner immediately across from Employee #1 and his coworker had just finished putting in his rivets and was standing at his palm buttons. Employee #1 was installing his last rivet, which required him to bend over the frame at an angle and place his head in close proximity to the frame. At this time, the gantry crane descended, traveling at 36 in. per second and covering the 48 in. in 1.5 seconds. Employee #1's head was pinched against the steel frame by one of the lifting claws. The machine then became locked in position, continuing to push his head against the steel frame. The machine shut down because the light curtain was broken by coworkers reaching in to help Employee #1, and at the same time one of the operators depressed his emergency STOP button. Employee #1 died of crushing injuries to his head. At the time of the accident, another operator was working at the southeast corner to the left of Employee #1. He had just come back from getting a crossmember and was placing in on the ground getting ready for the next frame; he was not on his palm buttons when the gantry descended. The other operator was at the southwest corner, had finished his rivets, and was depressing and holding his buttons when the crane came down. Only one of the four palm button stations was depressed at the time of the accident, and the light curtain was showing green for go. Subsequent examination of the light curtain determined that there was a dead zone between the curtain and the frame of the machine. At the lowest level, 24 inches were not covered by the light curtain; at the hip area, the distance increased to 31 inches. Immediately following the accident, the company installed another light curtain that covered all the dead zones missed by the original curtain.