What is Lessons Learned?

What is H2LL?

This database is supported by the U.S. Department of Energy. The safety event records have been contributed by a variety of global sources, including industrial, government and academic facilities.

H2LL is a database-driven website intended to facilitate the sharing of lessons learned and other relevant information gained from actual experiences using and working with hydrogen. The database also serves as a voluntary reporting tool for capturing records of events involving either hydrogen or hydrogen-related technologies.

The focus of the database is on characterization of hydrogen-related incidents and near-misses, and ensuing lessons learned from those events. All identifying information, including names of companies or organizations, locations, and the like, is removed to ensure confidentiality and to encourage the unconstrained future reporting of events as they occur.

The intended audience for this website is anyone who is involved in any aspect of hydrogen use. The existing safety event records are mainly focused on laboratory settings that offer valuable insights into the safe use of hydrogen in energy applications and R&D. It is hoped that users will come to this website both to learn valuable lessons from the experiences of others as well as to share information from their own experiences. Improved safety awareness benefits all.

Development of the database has been primarily supported by the U.S. Department of Energy. While every effort is made to verify the accuracy of information contained herein, no guarantee is expressed or implied with respect to the completeness, causal attribution, or suggested remedial measures for avoiding future events of a similar nature. The contents of this database are presented for informational purposes only. Design of any energy system should always be developed in close consultation with safety experts familiar with the particulars of the specific application.

We encourage you to browse through the safety event records on the website and send us your comments and suggestions. We will continue to add new records as they become available.

How does H2LL work?

If you have an incident you would like to include in the H2LL database, please click the "Submit an Incident" button at the top of the page. You will be asked for a wide range of information on your incident. Please enter as much of the information as possible. In order to protect your and your employer's identities, information that may distinguish an incident (your contact information, your company's name, the location of the incident, etc.) will not be displayed in the incident reports on H2LL.

Lessons Learned Corner

Visit the Lessons Learned Corner Archives.

Key themes from the H2Incidents database will be presented in the Lessons Learned Corner. Safety event records will be highlighted to illustrate the relevant lessons learned. Please let us know what you think and what themes you would like to see highlighted in this safety knowledge corner. You can find all the previous topics in the archives.

A process area alarm activated. The alarm was caused by an instrument channel located above a reaction vessel off-gas system final HEPA filter canister, which indicated 25% of the lower explosive limit (LEL) for hydrogen. Since the only source of hydrogen is from the reaction vessel during the reaction of sodium with concentrated sodium hydroxide, the immediate actions were to shutdown the reaction process and place the facility in a safe condition.

The root cause was inadequate or defective design. Had the pre-filter drains been vented to outside the building, no hydrogen could accumulate in the process area. The corrective action for this is to complete an Engineering Task Authorization (ETA) to install a sample/drain collection system with loop seals to prevent any release of view more

A brazing retort in a shop malfunctioned and resulted in an explosion that propelled the retort shell to the roof of the brazing area and then back to the floor. There were no injuries but damage was sustained by the furnace housing and the retort shell.

Administrative personnel were soon on the scene to make a preliminary assessment of the situation. An expert safety team was retained to assist in the investigation of the explosion. The safety team conducted their initial field investigation on the afternoon of the explosion and again on the following day.

Once it was determined that the explosion was the result of an ignition of a flammable mixture of hydrogen and air, the next step was to determine how air ended up in the retort, given that the retort is nominally view more

A hydrogen explosion occurred in an Uninterruptible Power Source (UPS) battery room. The explosion blew a 400 ft2 hole in the roof, collapsed numerous walls and ceilings throughout the building, and significantly damaged a large portion of the 50,000 ft2 building. Fortunately, the computer/data center was vacant at the time and there were no injuries.

The facility was formerly a large computer/data center with a battery room and emergency generators. The company vacated the building and moved out the computer equipment; however the battery back-up system was left behind. The ventilation for the battery room appeared to be tied into a hydrogen monitoring system. The hydrogen sensor was in alarm upon emergency responders arriving at the scene (post-explosion). 911 callers view more

A person working in a hydrogen lab unknowingly closed the wrong hydrogen valve and proceeded to loosen a fitting in one of the hydrogen gas lines. The pressure in the 1/4"-diameter hydrogen line was approximately 110 psig. Hydrogen escaped from the loosened fitting and the pressure release resulted in the tubing completely detaching and falling to the floor. The person noted seeing a white stream around the hydrogen jet leak. The person noted a color change and noise change as the leak ignited (this happened in a matter seconds and he did not have a chance to react). The person left the lab and pushed the emergency stop button. Someone else pulled the fire alarm. Both of these actions were designed to close the main hydrogen solenoid (shutoff) valve. The local emergency response view more

The interior of a small high-temperature furnace, approximately 24 inches high by 18 inches wide, became contaminated with an unknown material later identified as magnesium. The furnace was disassembled to clean the unknown material from the interior surfaces, and while attempting to clean the bottom of the furnace, the technician tapped the upper lip of the furnace with a spatula and the magnesium flashed. The technician was stepping back from the furnace when the magnesium flashed. He received minor eye irritation and his eyebrows were singed.

Later that week the same technician was attempting to clean the interior surfaces of the top of the furnace and sprayed, as directed, the interior of the top with a water-based cleaning liquid which consisted of 91% water. He stepped view more

Facility management confirmed that a hydrogen gas cylinder did not comply with the limiting condition for operation (LCO) for flammable gas control systems in the lab's safety requirements. Earlier erroneous calculations had shown that a release of the entire contents of the cylinder into the hood could not reach the lower flammability limit (LFL).

The facility manager determined that the LCO was applicable and immediately entered the action statement in the safety system, which required immediate termination of normal operations in the affected wing of the building. Because normal operations had already been terminated in the wing for HVAC maintenance, further efforts to terminate normal operations were not necessary. The hydrogen cylinder was removed from the hood, thus view more

A small hydrogen fire occurred in a chemical process hood. A chemist was performing an experiment reacting manganese dioxide with hydrogen to produce manganese oxide and water. The chemist had left the process, which would take approximately one hour to complete, and was working in a nearby lab. While the chemist was gone, a second worker heard a pop, saw the hydrogen fire in the hood, and requested the activation of a fire alarm. A third employee in the area activated a manual fire alarm. The chemist, upon hearing the fire alarm, returned to the room, shut off the hydrogen fuel supply, and evacuated the facility. The hydrogen fire lasted for approximately one minute. The remaining small fire was extinguished about 10 minutes later with a HALON portable fire extinguisher by a view more

An unplanned shutdown of the hydrogen supply system occurred, affecting the hydrogen furnaces in the plant. The apparent cause was an inadvertent valve closing, which was contrary to the written procedure.

A preventative maintenance activity was being conducted on the hydrogen gas system. Shortly after starting that work, various hydrogen gas users notified the emergency response personnel that the hydrogen supply safety alarms sounded, indicating an interruption of the hydrogen gas supply. As a result, the hydrogen furnaces shut down. This shut down is an automated process which injects an inert gas (nitrogen or argon) to prevent the introduction of oxygen and its mixing with any hydrogen gas. All shut downs functioned as designed. As a precautionary measure, fire protection view more

An apprentice mechanic lacerated his right forearm while quickly sliding out from under a hydrogen prototype bus when the bus slipped off a hydraulic jack. The apprentice and another mechanic had raised the bus about 1 foot from the ground to position it on jack stands when the hydraulic jack tipped over. The apprentice went to the site medical facility, where he needed five stitches to close the wound in his forearm.

The mechanics were raising the rear of a hydrogen prototype bus, like the one in the figure below, and placing it on jack stands. After chocking the wheels, they used bottle jacks on each side of the rear axle to raise the bus high enough to place a 20-ton hydraulic jack under the differential. With the bus resting on a pair of small jack stands, they raised the view more

An employee noticed an unusual smell in a fuel cell laboratory. A shunt inside experimental equipment overheated and caused insulation on conductors to burn. Flames were approximately one inch high and very localized. The employee de-energized equipment and blew out the flames. No combustible material was in the vicinity of the experiment. The fire was contained within the fuel cell and resulted in no damage to equipment.

The employee was conducting work with a fuel cell supplied by oxygen gas. The hazard control plan (HCP) associated with the work was for use with fuel cells supplied by air or hydrogen, but not for oxygen, which yields a higher current density. The technician had set up the station wiring to handle a current of 100 amps and the shunt was configured to handle a view more