Abstract: Employee #1, a manufacturing engineer, was clearing a jam on the assembly line that automatically inserted and bent pins on computer connectors. Electrical power to the unit was shut off. Employee #1 inadvertently leaned against the emergency STOP button, releasing residual air into the system that controlled the pneumatic clamp. His fingertip was avulsed by the clamp. The pneumatic system lacked a dump valve to prevent the build-up of residual air. At the time of the inspection, an air dump valve had already been installed. The assembly machine had adequate guarding (a light curtain) for normal operating hazards.