Abstract: At approximately 5:00 p.m. on September 25, 2002, Employee #1 was operating a Shelby leak tester, a device used to detect leaks on cast aluminum wheels. The leak tester consisted of two cavities and three plates, and could test two wheels at a time. The upper and lower plates moved to hold the wheel, while the middle plate was fixed. Employee #1 initiated the test cycle, activating the device with the two-hand control buttons, which caused the wheels to submerge into the water tank. The cavities rotated while the wheels were submerged, and Employee #1 looked for leaks. In addition to the two-hand control buttons, the point of operation was guarded with a light curtain. At the time of the accident, Employee #1 was working alone on leak tester number 2. He was removing a wheel from the cavity at the completion of a test cycle when he grabbed the wheel from the face and the upper plate came down, pinching his left hand against the face of the wheel. Employee #1 was transported by his employer to Long Beach Medical Clinic; he was later transferred to the Western Hand Center, where he underwent surgery. After the accident, a maintenance mechanic found that the limit switch, which signaled the machine's programmable logic control (PLC), was functioning inconsistently. The PLC functioned as if the cycle was complete and had started a "ghost cycle," during which time Employee #1 was injured. Subsequent investigation also revealed that the employer had verbally instructed some workers that wheels should be removed from the leak tester by pulling the valve stem or by grasping them with both hands from the side. The employer further told workers that, to avoid pinch points, wheels should never be grabbed from the face. However, the employer did not train Employee #1 about the potential hazards of grasping the wheel's face. The employer also did not have written procedures or methods to ensure that all exposed employees were aware of the potential hazards in the event of a malfunction of the limit switch.