Abstract: On April 20, 1993, Employee #1 was manually wiping the rollers on the Welex plastic extrusion machine with a rag wrapped around his hand and water. The rag caught in the in-running sides of the rolls and pulled his hand in. Employee #1 activated the trip wire, which stopped the rolls; however, the pneumatic valve was not working so it did not raise them at the end where Employee #1's hand was stuck. The roll should be raised approximately 4 inches at each end of the feed roll to provide a safe clearance between the rolls, but because of the broken valve, only one end was elevated during cleaning. Employee #1 thought this was a normal operation.