Hydrogen leaked from a 9,000-gallon horizontal liquid hydrogen tank in the rear of a high-intensity lamp manufacturing facility. The facility manager noticed the leak during his normal morning rounds and initiated the plant's emergency response policy, which included calling the local fire department. A large vapor plume (actually condensed moisture in the air) was visible 200 feet above the tank.
A valve packing started to leak during cold ambient temperatures. A technician was dispatched. He first reduced the pressure to minimize the release and then re-tightened the packing to stop the leak.
Hydrogen was released near the ground when the vent line from a 13,000-gallon liquid hydrogen storage vessel suffered damage from unusually high winds. The toppled vent line did not shear or tear, but sustained a kink that restricted hydrogen flow and created a back pressure on the vessel relief system.
Repair efforts were hampered by the potential for cold hydrogen gas, a flammability hazard, in the work area. Shut off or redirection of the hydrogen was not possible, and variable breezes made set up of safe zones uncertain. A protocol had not been prepared for this scenario.