Event
- Event ID
- 320
- Quality
- Description
This event occurred at after the testing of a liquid hydrogen tank. The hydrogen was then removed and the tank purged with helium gas for more than 4 hours. A flange was then removed to allow for insertion of smaller tank, at which time an explosion occurred.
- 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
- cryogenic vessel
- Failure mode
- internal explosion
- Initiating cause
- inadequate or no purge
- Root CAUSE analysis
The INITIATING CAUSE was the formation and ignition of an air-hydrogen explosive mixture in the tank.
Hydrogen gas was still present after the 4.5 hours of purging, when a second tank was inserted. The outer tank was still cold and air could enter the chamber by cryo-pumping. The ignition source was probably a hot wire level sensor, a platinum wire heated to above the ignition temperature of the mixture.The ROOT CAUSE could be identified in an inadequate purging procedures and lack of independent assessment of the tank composition.
- Root causes
- Date entry in HIAD
- 30/10/2025
Facility
- Application
- Non-road vehicles
- Sub-application
- Aerospace
- Hydrogen supply chain stage
- All components affected
cryogenic tank
- Process temperature range [C]
- cryogenic temperature (below -50°C)
- Location type
- Unknown
- Location
- countryside or desert
- Operational condition
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Probable IGNITION SOURCE
- Explosion type
References
- Sources categories
- ORDIN
- Reference & weblink
Mishap no 31 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
