Abstract: On August 3, 2001, Employee #1 was preparing a spool on a coil tubing unit for change out and replacement with another spool containing different diameter pipe or tubing. A coil tubing unit is a mobile unit that carries 15,000 to 20,000 feet of pipe coiled around a spool for deployment into existing oil or gas wells. Employee #1 was standing on top of the spool, about 12 feet above ground level. As he cut the tubing to free it from the injector, the approximately 10-foot in diameter spool he was standing on began to turn slowly. The spool's hydraulic system was engaged, the brake was not set, and the spool was not secured or chained. In addition, Employee #1 had tied his safety lanyard off to the rim of the spool. Tied at the waist and unable to unhook his lanyard, Employee #1 was subsequently pulled through a 10-inch gap between the spool and its frame. The lanyard broke away and the spool then made several revolutions before another operator could climb up into the control room to stop the spool. The incident resulted in a fatal injury to Employee #1, who was asphyxiated.