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 facility manager was notified that an authorization basis requirement, associated with roofing contractor work, had not been met. The requirement was that an unused hydrogen gas cylinder adjacent to the building and not connected to a manifold be removed prior to the use of propane tanks for the hot tar portion of the work.

The project manager failed to remove the extra gas bottle as required because he did not recognize from the bottle color and lack of stencil that the bottle contained hydrogen.

An explicit checklist containing all the administrative controls and requiring careful inspection was not available at the time of the inspection. The checklist preparation also would have made obvious the fact that administrative controls had been established. The project view more

A facility experienced a major fire in its Resid Hydrotreater Unit (RHU) that caused millions of dollars in property damage. One employee sustained a minor injury during the emergency unit shutdown and there were no fatalities.

The RHU incident investigation determined that an 8-inch diameter carbon steel elbow inadvertently installed in a high-pressure, high-temperature hydrogen line ruptured after operating for only 3 months. The escaping hydrogen gas from the ruptured elbow quickly ignited.

This incident occurred after a maintenance contractor accidentally replaced an alloy steel elbow with a carbon steel elbow during a scheduled heat exchanger overhaul. The alloy steel elbow was resistant to high-temperature hydrogen attack (HTHA), but the carbon steel elbow was not. 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

A laboratory research technician entered a lab to begin preparing samples that were to ultimately be purged in an anaerobic chamber (glove box) located in that room. As the technician walked into the lab, she looked at the chamber to see if it was adequately inflated. This chamber is equipped with a gas concentration meter, capable of simultaneously displaying the oxygen and hydrogen concentrations of the chamber atmosphere. Under normal operating conditions, the atmosphere inside the chamber is comprised of 0% oxygen (as intended/desired for an anaerobic atmosphere), approximately 2-3% hydrogen, and with the remaining balance being nitrogen (approximately 98-97%). Under such normal operating conditions, the hydrogen concentration inside the chamber is less than the lower explosive view more

A hydrogen monitor leak detector (HMLD) was out of service because of a failed membrane. The HMLD heater circuit and the ion pump and its associated controller were de-energized and red-tagged to ensure the system remained shut down. The ion pump and controller were later found energized. The ion pump circuit is a low-power (120-V, 1 amp) circuit and the pump operates in the micro-amp range. There was no damage to equipment from this inadvertent energization. There was also no personnel safety hazard since the tag out was not for maintenance purposes and since the system was in its normal operating configuration.

The direct cause is listed as personnel error, inattention to detail. This category most closely describes the inadvertent actuation of the controller toggle switch. view more

An individual inadvertently connected a pure hydrogen gas bottle to a chamber/glove box as opposed to a 10% hydrogen (in nitrogen) bottle that should have been used. [The wrong bottle had mistakenly been delivered, and the inexperienced individual did not know the difference.] The hydrogen concentration increased within the chamber to about 9%. Since there was insufficient oxygen in the chamber to support combustion, the hydrogen did not burn, and was quickly diluted with nitrogen.

The contractor was replacing a needle valve and a check valve on the nitrogen purge line to the dispenser because of a small leak at the connection between the needle valve and the check valve. On reinstalling the valves, the contractor installed the check valve backwards, causing the pressure disk in the regulator to fail, venting about 1000 psig hydrogen into the air for about 10 seconds. This was found during testing of the contractor's work before the system was returned to normal service.

DESCRIPTION: On a Friday afternoon in 2007 a traffic accident occurred at the corner of two urban streets. Two vehicles were involved. Each vehicle contained a single driver (no passengers). Vehicle 1 was a Fuel Cell Vehicle. Vehicle 2 was a conventional Toyota Camry. Vehicle 1 was traveling west, approaching an intersection with a green light, and proceeded into the intersection. Vehicle 2 was traveling north on a cross street. The driver of Vehicle 2 incorrectly perceived a green light and proceeded into the intersection. The vehicles collided in the intersection.

RESPONSE: The police were coincidentally in the area and able to respond quickly to the site. The vehicles were moved out of the intersection. Vehicle 1 (fuel cell vehicle) shut down upon impact and was pushed out of view more

A five-pound CO2 cylinder being stored in a compressed gas storage cage at a power plant failed catastrophically and became a missile. The cylinder destroyed the storage cage, then struck one of six stationary hydrogen storage cylinders used as emergency make-up for the hydrogen supply system. One of the hydrogen cylinders was broken away from its mounts and moved 10 feet from its original location. The loss of this cylinder severed the manifold tubing, creating a leak path to the atmosphere for the remaining five hydrogen cylinders. The leaking hydrogen gas apparently self-ignited, engulfing the immediate area. The site fire brigade responded and used hose lines from a distance to provide cooling until the hydrogen supply was consumed. The fire was out within seven minutes, and no off view more