Abstract: Employee #1 was standing atop a 160-ft-high by 33-in.-diameter silo in a cement storage terminal, giving signals to a crane. The crane, which had a 160-ft-long main boom and a 50-ft-jig, was fitted with a scraper device. The H-shaped scraper was constructed of 8-in.-diameter pipe with a 20-ft-long center piece made of two 10-ft-long pieces, perpendicular to the smaller pipe. The scraper was lowered through a hole in the top of the silo and raised and lowered to loosen cement powder that had stuck to the sides of the silo. Apparently the scraper was lowered too far and cement powder broke loose from the sides, covering the scraper with approximately 35 ft of cement. This pulled the jig boom forward about 3 ft and into the pipe handrail, causing the boom to collapse and fall. The boom struck Employee #1 on the head, killing him.