Event
- Event ID
- 392
- Quality
- Description
A LH2 tank exploded causing injury and damage when hot wire sensors were used in tank after purging.
- 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
- LH2 tank (stationary)
- Failure mode
- internal explosion
- Initiating cause
- inadequate or no purge
- Root CAUSE analysis
The INITIATING CAUSE was the production of an explosive air-hydrogen mixture inside a not properly purged tank.
Hot wire sensors were being used in the tank and caused the ignition
Nothing is known on the reasons for this inadequate purge, so that the ROOT CAUSE could be attributed generally to job factors, and to risk armament shortcoming, due to the use of wrong sensors.- Root causes
- Date entry in HIAD
- 01/11/2025
Facility
- Application
- Hydrogen stationary storage
- Sub-application
- LH2 storage
- Hydrogen supply chain stage
- All components affected
tank
- Process temperature range [C]
- cryogenic temperature (below -50°C)
- Process pressure range [MPa]
- low to medium pressure (below 2 MPa)
- Location type
- Unknown
- Location
- unknown
- Operational condition
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 1
Lesson Learnt
- Lesson Learnt
Inadequate purging is a recurrent root cause for explosion during maintenance. Specifically purging of liquid hydrogen is a complex operation, implying effective warming up and gas replacement. In this case, the ignition source was probably a hydrogen sensor. If this assumption is correct, the hydrogen sensor had the goal to detect possible residual hydrogen. Whenever there is a possibility of hydrogen presence, ignition source must be avoided, including the sensors self.
In-depth data
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Probable IGNITION SOURCE
- Explosion type
References
- Sources categories
- ORDIN
- Reference & weblink
Mishap no 54 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
