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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.

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…

Metallurgical examination of the two failed disks by light optical microscopy (LOM), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopic analysis (EDS) found them to be fabricated from pure nickel with evidence of…

1. Evaluate any change in normal procedures or conditions for storage of aluminum hydride products. In this case, the aluminum hydride material was typically stored at -35°C in the glove box freezer. However, due to a change in glove boxes, this…

Inadequate Safeguards - The system was designed with low-point drains to facilitate water removal, however, these were found to be inadequate in both location and size. The fact that the mixed feed pre-heat coil was not self-draining was unknown…

Provide additional retraining of operators. Curriculum should emphasize the proper response to high oxygen in the hydrogen gas.
Evaluate current knowledge of operators. Operators should know proper response, such as contacting engineering…

Operation and management of the hydrodesulfurization unit should be strengthened to account for abnormal phenomena such as local corrosion.
The safety review system for remodeling existing equipment and facilities should be strengthened.…

The dilution water for making a polythionic acid aqueous solution was changed from industrial water to pure water to lower the chlorine concentration in the piping.
Water that accumulated in the drain was removed before heating began.…

Hazards should be eliminated to the extent possible rather than depending on workers to follow an operations manual.

Potassium carbonate draw-off operations should be improved, and the operations manual should be revised. The manual should…

This incident emphasizes the need for proper gas detection and ventilation systems, as well as fire suppression systems, in laboratories using and storing hydrogen. This is especially true when open flame burners are in close proximity.…

Routine maintenance activities on pressurized hydrogen systems should be conducted per written design specifications. The procedures should provide detailed oversight regarding bolt, nut and fitting replacements or repairs. A formal review…

Although a functional fire protection system would have helped to extinguish the fire, a properly installed hydrogen detection system, coupled with a properly designed ventilation system, could have prevented the incident altogether.Hydrogen…

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…

Normally hydrogen fires are not extinguished until the supply of hydrogen has been shut off due to the danger of re-ignition and explosion. During a gas leak/fire, it is important to shut off the source of the hydrogen if it is safe to do so. If…

All tank trailers should have a safely accessible auxiliary shut off valve in case of spills.
Emergency personnel need to have access to all of the appropriate protective clothing, including shoes. Liquid hydrogen is stored at 20.28 Kelvin…

First, it appears that the system may not have been vented properly. CGA G-5.5 should be used for determining safe locations based on the variables of the specific setup. Also, if the compressor was tied to a storage system, a backflow prevention…

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…

In addition to resealing the glove box window, a positive pressure of argon gas was maintained inside the glove box while the course of action was planned. Subsequently, the glove box was cleaned up by specialized hazardous materials personnel…

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.

In the future, refining, petrochemical, and chemical industries need to review material verification programs to ensure that the maintenance procedures include sufficient controls and positive material identification (PMI) testing to prevent…

The investigative report noted that the explosion could have been prevented by (among other things) a continuous gas analyzer test of oxygen and hydrogen product purity. The continuous analyzer should be interlocked to shut the electrolyzer down…

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