Event
- Event ID
- 427
- Quality
- Description
- While welding cable suspended over stainless steel H2 instrument line, two holes were burned through tubing. A hissing sound was heard and operator closed a valve. In feeling for gas leak which had been ignited, the operator's hand was burned.
[Ordin, NASA (1974)] - Event Initiating system
- Classification of the physical effects
- Hydrogen Release and Ignition
- Nature of the consequences
- Macro-region
- North America
- Country
- United States
- Date
- -
- Main component involved?
- Pipe
- How was it involved?
- Leak & Formation Of A Flammable H2-Air Mixture
- Initiating cause
- Wrong Operation
- Root causes
- Root CAUSE analysis
- The INITIATING CAUSE was a short circuit during welding caused the pinholes in the tubing containing the compressed hydrogen.
The ROOT CAUSE was probably a lack of effective operative instructions / procedures aiming at avoiding hazardous actions in the neighbourhood of a system containing flammable materials.
Facility
- Application
- Non-Road Vehicles
- Sub-application
- Aerospace
- Hydrogen supply chain stage
- Unknown (No additional details provided)
- All components affected
- instrumentation (hydrogen) line
- Location type
- Unknown
- Operational condition
Emergency & Consequences
- Number of injured persons
- 1
- Number of fatalities
- 0
Lesson Learnt
- Lesson Learnt
- H2TOOLS provided this general lesson:
“Because of the near invisibility of a hydrogen flame in daylight and hydrogen's extremely low ignition coefficient, if a known leak is present (e.g., an audible hissing), ignition should always be presumed.“
Event Nature
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Presumed ignition source
- Welding
- Ignition delay
- N
References
- Reference & weblink
Mishap no 65 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/19740020344Lowesmith 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)Also uptaken in US database H2TOOLS<br />
https://h2tools.org/lessons/invisible-hydrogen-fire-injures-technician<… />
(accessed Decembr 2025)
JRC assessment
- Sources categories
- ORDIN
