Abstract: At approximately 7:40 p.m. on January 28, 1991, Employee #1 was troubleshooting an automotive engine cylinder head transfer line. A heat treat machine was located adjacent to, and worked in conjunction with, the transfer line. The cylinder head transfer line advanced heads into the Tocco-Lamb heat treat machine (s/n 7120122). A cyclic problem developed with the heat treat machine, which stopped the transfer line feed through a limit switch that senses the advancement, or lack thereof, of the heads. Employee #1, a set-up person, swung open a hinged (non-interlocked) gate to the transfer line shuttle area, leaned in, and moved a cylinder head away from the limit switch. Since the electro-hydraulic energy source to the transfer shuttle line was still energized, it caused the shuttle to shift to the right. Employee #1's head was crushed between the shuttle arm and the machine frame, a space that diminished from 17 to 3 3/4 inches wide. The causal factor was inadvertent machine startup during a servicing function.