Abstract: At approximately 5:00 p.m. on August 23, 2010, Employee #1, a pipefitter, was working with a crew of five pipefitters and one operator, moving a long section of 8-inch high density polyethylene (HDPE) pipe into position onto a McElroy Manufacturing Fusion Machine, MN 6-12. The crew was staging the part to weld a flange and Chicago fitting onto the end of the 8-inch HDPE the following day. This was being done to provide water for a hydrotest of fabricated process piping prior to being placed into service per applicable API mechanical integrity standards. The 8-inch HDPE pipe was being run from a retention pond several hundred yards to the north, and had previously been used to run water elsewhere on the new construction project. There was standing water in the charged line. The crew cut the 8-inch HDPE pipe and rigged a 12-ft endless synthetic web sling to the bucket of a Caterpillar 346 CL. The cab of the Caterpillar 346 CL was positioned 21 feet from the McElroy fusion machine. As the Caterpillar operator began to drag the long section of 8-inch HDPE into position, his primary attention was focused on watching the movement of the pipe on the ground. As the forward section was elevated by the endless sling, rigged 10-ft to 15-ft from the end of the pipe in a choker hitch, the sling slid out of the wet/smooth surface of the 8-inch HDPE pipe. The pipe struck Employee #1 in the head with such force that it broke the suspension of his Bullard MN S-71 protective helmet. He died as a result of the blow to his head.