Abstract: On October 10, 2011, Employee #1, a lead facility technician, was preparing to perform a download on a control room computer system. He was alone conducting a visual inspection of the equipment in the utilities plant to verify all of the equipment was working properly prior to the download. When Employee #1 was near an Aquafine ultraviolet water treatment unit (Model Number SCD-1750 H 4-Pack), a compression nut that held a quartz sleeve and UV lamp in place failed on unit 1. The sleeve ejected and struck Employee #1's left femoral area. Coworkers in the break room located approximately 100 ft away heard a loud noise and investigated. They found Employee #1 on the ground bleeding from the left side of his groin area and water pouring out of the unit. He was killed. The operating pressure in the ultraviolet water treatment unit was approximately 100 psi with a flow rate of approximately 300 gpm.