Abstract: At approximately 12:15 p.m. on May 25, 2010 Employee #1 was attempting to repair the lower vacuum pump unit for a plasma vacuum machine, after determining that there was an accumulation of dust causing operational problems. Employee #1 deenergized and locked out the electrical power to the overall unit and removed the connection hose from the upper vacuum unit, to gain a limited access of about eight inches, to the opening of the lower unit. Employee #1 tried unsuccessfully, to manually unbind the rotary screw type vacuum assembly by reaching with his hand down into approximate five or six inch opening to the lower housing unit. Employee #1 was assisted in the repairs by another coworker. The coworker removed the exhaust hose leading from the units' lower plate, and applied a hose for Shop Vac, and turned it on, using the vacuum to collect loosened dust, while Employee #1 applied compressed air from a hose nozzle to the top of the unit to loosen the dust. While the coworker continued to apply the vacuum from below, Employee #1 stopped the compressed air application, and again inserted his hand to attempt to unbind the rotary screw assembly. When Employeee #1 freed up, the middle finger tip of his left hand got caught in the rotating screw veins. Employee #1 suffered partial amputation including bone and tissue above the first knuckle joint.