An isolated vehicle hydrogen tank needed to be de-fueled, but the standard operating procedure could not be followed because the tank was inoperable and had to be manually vented with a special tool. This intentional release of hydrogen was done outside an R&D facility, but it unintentionally activated two sensors on vehicle bay gas detectors (at 20% LFL) in the adjacent indoor facility. Although each person involved in this activity was qualified to perform the work, the circumstances at the time were unusual.

Incident Date
Oct 01, 2007
  • Hydrogen Storage Equipment
  • Gas cylinder
  • Pressure Relief Devices
  • manual valve
Damage and Injuries
Contributing Factors
When Incident Discovered
Lessons Learned

Several best practices resulted from this incident and will be implemented if similar circumstances present themselves in the future.

Close bay door.
Keep within proximity of bay.
Be aware of other bays operating with open doors.
Notify others in the area of venting hydrogen.
Have at least two knowledgeable people present when working.
Secure an isolated tank that is not in a vehicle.
Provide a vent stack routed to a safe location if possible.
Use a de-fueling port if available.