scope:

Description of Driving Event:

Performing work on S70-0613-00-001-0120 to change improperly sized flex hose restraints. When attempting removal of flex hose, gaseous nitrogen was released due to a partially opened valve in the system. Isolation valve A102736 on the F70-0014 panel was closed to stop the gaseous nitrogen flow to the flex hose. The gaseous nitrogen contained small quantities of N2H4 vapors. The work authorizing document did not contain instructions or work stops to verify that there was no pressure on the flex hose.