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Disclaimer: The Lessons Learned Database includes the incidents that were voluntarily submitted. The database is not a comprehensive source for all incidents that have occurred.

In addition to the probable causes listed above, the lack of a standard operating procedure for hydrogen leak detection was one of the probable causes of this incident. Additional contributing factors included the following:
- Severe pipe…

Lessons Learned The site initiated the establishment of a field patrol and strengthened their onsite monitoring of mechanical equipment during a plant-wide temperature rise.

Quantitative control of tightening torque on bolts should be…

Standard procedures must be followed at all times. The importance of doing so should be frequently reinforced through safety communications to all staff.

The use of inerting gas or other means of separation should be employed when conducting mechanical work where hydrogen gas could be present. More importantly, per CGA S1.3, the vessel should be equipped with a dual relief system that can isolate…

All valves and connectors should be clearly labeled to minimize chances for mis-connection. All technicians must be trained on proper procedures for both taking systems offline and bringing them back online.

Valves for compressed hydrogen…

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. The primary cause of this incident…

The charging characteristics of a battery vary with the condition of the battery and are proportional to the ampere-hour capacity of the battery. During charging, when a battery is close to being fully charged, hydrogen and oxygen both offgas in…

It is characteristic of silver/zinc batteries to outgas both hydrogen and oxygen for several hours after discharge. Also, in the future, the battery should be properly secured inside the container.

A flammable gas explosion is an analyzed hazard and gas detection/shut off is a safety significant control system that requires a limiting condition for operation (LCO). The rigor of the evaluation of flammable gas systems was inadequate. There…

Diligence needs to be practiced when performing assigned work tasks. To guard against complacency, it is necessary to emphasize adherence to established procedures, including appropriate reviews of preventive maintenance instructions (PMI) and…

Hazard assessment is critical during the design, fabrication, and installation of system modifications to ensure hazards and potential hazards are addressed prior to system start-up and operation.

The primary lesson learned was that the active hydrogen facility and existing operating procedure, at the time of the accident, were sound. While this now has been determined, the previous form(s) of this system, associated documentation, and…

Procedures will be revised to include specific information about hydrogen sensors and alarm controls. Caution will be added about sparks and flames in the fuel cell operation area. Workers will be cautioned that shunt resistors may reach high…

Hazard analysis should consider potential leak locations, potential ignition sources in the vicinity, and the potential for accumulating flammable gases in that area.

Users should leak-check all cylinders upon installation. This event…

Key:

  • = No Ignition
  • = Explosion
  • = Fire
Hydrogen Incident Summaries by Equipment and Primary Cause/Issue
Equipment / Cause Equipment Design or Selection Component Failure Operational Error Installation or Maintenance Inadequate Gas or Flame Detection Emergency Shutdown Response Other or Unknown
Hydrogen Gas Metal Cylinder or Regulator   3/31/2012
4/30/1995
2/6/2013
4/26/2010 12/31/1969     3/17/1999
11/1/2001
12/23/2003
Piping/Valves 4/4/2002
2/2/2008
5/11/1999
4/20/1987
11/4/1997
12/31/1969
8/19/1986
7/27/1991
12/19/2004
2/6/2008
10/3/2008
4/5/2006
5/1/2007
9/19/2007
10/31/1980
2/7/2009 1/24/1999
2/24/2006
6/8/1998
12/31/1969
2/7/2009

9/1/1992
10/31/1980

10/3/2008  
Tubing/Fittings/Hose   9/23/1999
8/2/2004
8/6/2008
9/19/2007
1/1/1982 9/30/2004
10/7/2005
  10/7/2005  
Compressor   10/5/2009
6/10/2007
8/21/2008
1/15/2019
    10/5/2009 8/21/2008  
Liquid Hydrogen Tank or Delivery Truck 4/27/1989 12/19/2004
1/19/2009
8/6/2004 12/31/1969   1/1/1974 12/17/2004
Pressure Relief Device 7/25/2013
5/4/2012
1/15/2002
1/08/2007
12/31/1969        
Instrument 1/15/2019 3/17/1999
12/31/1969
2/6/2013
    11/13/73    
Hydrogen Generation Equipment 7/27/1999     10/23/2001      
Vehicle or Lift Truck   7/21/2011         2/8/2011
12/9/2010
Fuel Dispenser   8/2/2004
5/1/2007
6/11/2007
9/19/2007
  2/24/2006
1/22/2009
     
Fuel Cell Stack            

5/3/2004
12/9/2010
2/8/2011

Hydrogen Cooled Generator       12/31/1969
2/7/2009
     
Other (floor drain, lab
anaerobic chamber,
heated glassware,
test chamber,
gaseous hydrogen
composite cylinder,
delivery truck)
  11/14/1994
7/21/2011
7/27/1999
6/28/2010
8/21/2008
12/31/1969
3/22/2018
    6/10/2019
  • = No Ignition
  • = Explosion
  • = Fire