scope:

Description of Driving Event:

A maintenance team was removing a gate valve from a high pressure (5000 pounds per square inch) nitrogen trailer at the fill end of the trailer. After the valve bolts were removed and the employee tapped on the valve to loosen it, the valve flew off and hit one of the maintenance employees. The employee was thrown 15 feet through the air and against an I-beam, resulting in a fatality. Preliminary information indicated that the system was not under pressure and the valve gauge reading was zero pressure.

[This event occurred during work external to NASA but includes information that is pertinent to NASA operations.]