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Clean Hydrogen Partnership

Explosion of a LH2 system

Event

Event ID
316
Quality
Description
A liquid hydrogen system exploded and burned during fill operations due to inadequate purging after the previous operation.
[Ordin, NASA (1974)]
Event Initiating system
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
-
Main component involved?
Lh2 Storage Vessel
How was it involved?
Internal Explosion (H2-Air Mixture)
Initiating cause
Inadequate Or No Purge
Root causes
Root CAUSE analysis
The IMMEDIATE 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.

Facility

Application
Non-Road Vehicles
Sub-application
Aerospace
Hydrogen supply chain stage
Hydrogen Transfer (No additional details provided)
All components affected
LH2 tank
Location type
Unknown
Operational condition

Emergency & Consequences

Number of injured persons
0
Number of fatalities
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.

Event Nature

Release type
gas
Involved substances (% vol)
H2 100%
Presumed ignition source
No ignition

References

Reference & weblink

Mishap no 25 in <br />
P. L. Ordin, Review of hydrogen accidents and incidents in NASA operations, 1974, NASA TM X-71565<br />
https://ntrs.nasa.gov/citations/19740020344

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

Hankinson and Lowesmith, Qualitative Risk Assessment of Hydrogen Liquefaction, Storage and Transportation, FCH JU project IDEALHY, Deliverable 3.10 (2013)<br />
confidential<br />
(accessed October 2025)

Hankinson and Lowesmith, HAZIDs for Hydrogen Liquefaction, Storage and Transportation , FCH JU project IDEALHY, Deliverable 3.11 (2013)<br />
https://www.idealhy.eu/uploads/documents/IDEALHY_D3-10%20HAZIDs_Liquefa… />
(Only summary publicly available, accessed October 2025)

JRC assessment