Abstract: At approximately at 4:00 p.m. on April 7, 2001, a mechanic and two other employees working in a manufacturing plant were unjamming an Allen wrench from a Langen Case Packer carriage machine located in the envelope department. The machine was not completely deenergized. The Mechanic was aligning or doing fine adjustment of the rails when he discovered the small boxes were not aligned straight. They were going sideways. The mechanic was adjusting the rails while the machinery was on. He went inside to see if he could find out what was causing the problem. He adjusted the railing using the one of the Allen wrenches from the set. The rest of the Allen wrenches were placed on a long piece of metal that was in the path of the carriage. During this time, the mechanic was in and out of the machine making the adjustments, while the machine was on. The boxes became full, the carriage indexed forward and the mechanic's set of Allen wrenches stuck. The mechanic realized that the rest of his Allen wrenches were still inside the enclosure. The mechanic opened the interlocked door from behind him so that it would release the air. Employee #2 and Employee #3 opened the other two interlocked doors. The mechanic asked Employee #3 to close the red main valve but he was unable to push the red air valve. The mechanic pried out the set of Allen wrenches with his hand. The set of Allen wrench slipped and the carriage moved forward swiftly amputating his left thumb.