LH2 leak from a stationary tank

Event

Event ID: 1231
Quality: 2
Description: A leak occurred near the bottom of a stationary liquid hydrogen tank with a capacity of a 6,000-gallon. The leak was localised on a valve and was visible due to the air condensation forming white clouds rosing upward and dissipating. Ignition did not occur.

Fire fighters tested hydrogen concentration in air around the leaking place and determined it to be safe. After which, plant workers shut off a secondary valve, isolating the leaking valve.
Preliminary investigations indicated that a faulty O-ring may have been the cause.
Event Initiating system: Hydrogen System Initiating Event
Classification of the physical effects: Unignited Hydrogen Release
Nature of the consequences: Leak No Ignition (No additional details provided)
Macro-region: North America
Country: United States
Date: 23/12/2013
Main component involved?: Cryogening Valve
How was it involved?: Leak & Formation Of A Flammable H2-Air Mixture
Initiating cause: Material Degradation (Generic)
Root causes: Unknown (No additional details provided)
Root CAUSE analysis: Nothing is known on the ROOT CAUSE. The fact that the leak was identified first at the bottom of the tank, and later also from the top of the tank (see reference), suggest a possible degradation of the thermal isolation capacity of the external shell of the tank. But it cannot be confirmed by unavailability of the investigation report.

Application: Hydrogen Stationary Storage
Sub-application: LH2 stationary tank
Hydrogen supply chain stage: Hydrogen Storage (No additional details provided)
All components affected: tank
Location type: Open
Operational condition: Normal
Pre-event occurrences: the quantity of hydrogen in the tank during leak is unknown.

Reference & weblink: ISSS source news of 23 Dec 2013<br />
https://www.isssource.com/leaking-valve-leaks-hydrogen/<br />
(accessed November 2025)