Event
- Event ID
- 316
- Quality
- Description
A liquid hydrogen system exploded and burned during fill operations due to inadequate purging after the previous operation.
- Event Initiating system
- Classification of the physical effects
- Unignited Hydrogen Release
- Nature of the consequences
- leak no ignition
- Macro-region
- North America
- Country
- United States
- Date
- -
- Component involved
- LH2 tank (stationary)
- Failure mode
- internal explosion
- Initiating cause
- inadequate or no purge
- Root CAUSE analysis
The INITIATING CAUSE was the explosion of non-further specified LH2 storage.
Purging had been accomplished with gaseous nitrogen but had not been repeated with gaseous helium. Hydrogen and air were still in the system.The ROOT CAUSE was only partial of the purging procedure before filling.
- Root causes
- Date entry in HIAD
- 30/10/2025
Facility
- Application
- Non-road vehicles
- Sub-application
- Aerospace
- Hydrogen supply chain stage
- All components affected
LH2 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
Lesson Learnt
- Lesson Learnt
Liquid hydrogen storage systems require purging with helium, due to the risk of liquefaction (or even solidification) of nitrogen, which is the most common inert gas used for purging gaseous systems. For a short summary of the various purging approaches, see H2TOOLS platform at https://h2tools.org/bestpractices/operating-procedures/purging#:~:text=Helium%20is%20used%20because%20at,another%20part%20of%20the%20system.
Why in this event the helium purge was omitted is unknown.
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Probable IGNITION SOURCE
References
- Sources categories
- ORDIN
- Reference & weblink
Mishap no 25 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
