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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…

Carefully revise the risk assessment process to evaluate any confined areas where hydrogen is handled.
Separate the fire and gas detection alarm system from the process information to provide easy and clear identification.
Refresh…

The investigation determined that hydrogen was formed by the reaction of hot aluminum and water, air was admitted via the inspection door, and the mixture was ignited by the hot clinker or sparks from the chisel. Aluminum should have been…

The investigation team concluded that hydrogen gas was released through a failed 19-inch diameter gasket and ignited under the roof of the compressor shed where it was partially confined. Some gas escaped from the shed prior to the explosion, but…

Several procedural and design changes should be considered for the future:

Replace the use of pure hydrogen with a 95:5 mixture of nitrogen and hydrogen to reduce the possibility of an explosive atmosphere occurring. Laboratory personnel…

Many accidents reported from paper mills have much in common with this incident. Microorganisms in the process water with pulp produce hydrogen gas that mixes with air to form an explosive atmosphere. The ignition source is typically sparks…

1. Management must ensure that operating decisions are not based primarily on cost and production. Performance goals and operating risks must be effectively communicated to all employees. Facility management must set safe, achievable operating…

The visiting intern had several years of experience in research projects and tasks that were similar to those in progress at this laboratory. This led to the incorrect assumption that formal introductory training for this laboratory was…

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…

When truck drivers are carrying new trailers, with new load distribution characteristics, they need to exercise caution, especially on hazardous roadways such as the one described in this occurrence. If the trailer stack would have been smashed…

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.

Battery power supplies require adequate ventilation for all operations, or the battery box should be designed to:

Eliminate all sparking devices
Ventilate during charging operations
Provide inert gas purge and…

Batteries stored on a charger can explode during use if overcharged.

Recommendations

Use automatic current limiting or timed circuit chargers when charging batteries.
Operators should be aware of safe practices and proper…

The lesson to pass on is that ventilation is critical in UPS battery rooms. Great care should be taken to ensure that the ventilation system is operational and brings in enough outdoor air to properly ventilate the enclosure.

Electrical…

Test safety system components even if they are new.
Do not rely on listening for valve movement as confirmation that a valve is closing; measure downstream pressure to determine if the valve is really sealing properly.
Lock the…

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…

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