Event
- Event ID
- 435
- Quality
- Description
During loading of a LH2 storage tank, the vent valve on the tank was opened and then ignition occurred near the instant that the valve was fully open. A light pressure wave was produced. The cloud contained about 57 kg of hydrogen at ignition. Water was used to cool the area. At the end of the emergency, inspection showed a leak inside the vent valve body which was still burning. The tank pressure was below 4 psig.
- Event Initiating system
- Classification of the physical effects
- Hydrogen Release and Ignition
- Nature of the consequences
- Macro-region
- North America
- Country
- United States
- Date
- -
- Component involved
- valve (generic)
- Failure mode
- leak & ignition
- Initiating cause
- material degradation (generic)
- Root CAUSE analysis
The INITIATING CAUSE appears to consist in two separate sub-events: the opening of the vent valve with consequent formation of air-hydrogen explosive mixture at vent opening, and the crack in the body of the vent valve, which produced a local fire.
A temporary venting system was being used with an unsatisfactory vent valve. Static discharge was assumed to be the IGNITION SOURCE.The report does not explain why the vent valve was opened, nevertheless the ROOT CAUSE could be tentatively identified in a combination of erroneous installation and operation of the temporary venting system and a material failure.
- Root causes
- Date entry in HIAD
- 01/11/2025
Facility
- Application
- Non-road vehicles
- Sub-application
- Aerospace
- Hydrogen supply chain stage
- All components affected
vent valve, tank
- Process temperature range [C]
- cryogenic temperature (below -50°C)
- Process pressure range [MPa]
- low to medium pressure (below 2 MPa)
- Location type
- Open
- Location
- industrial area
- Operational condition
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
In-depth data
- Release type
- liquid
- Involved substances (% vol)
- H2 100%
- Released amount (kg)
- 57
- Release pressure [MPa]
- > 1.0
- Probable IGNITION SOURCE
- Explosion type
References
- Sources categories
- ORDIN
- Reference & weblink
Mishap no 76 in
P. L. Ordin, Review of hydrogen accidents and incidents in NASA operations, 1974, NASA TM X-71565
https://ntrs.nasa.gov/citations/19740020344Hankinson and Lowesmith, Qualitative Risk Assessment of Hydrogen Liquefaction, Storage and Transportation, FCH JU project IDEALHY, Deliverable 3.10 (2013)
confidential
(accessed October 2025)Lowesmith et al., Safety issues of the liquefaction, storage and transportation of liquid hydrogen: An analysis of incidents and HAZIDS, Int. J. Hydrogen energy (2014) https://doi.org/10.1016/j.ijhydene.2014.08.002
