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.

One afternoon, a hydrogen-monitoring system alarm sounded. The system isolated the building hydrogen gas distribution system from the source and purged the distribution piping with argon. Activities were terminated and personnel were immediately evacuated.

Prior to re-entry, the hydrogen system was walked down to ensure that it was in a safe state and that the remote indicator showed no hydrogen present in the facility. Normal operations were suspended until the cause of the alarm could be determined.

The cause of the alarm was not escaping hydrogen gas, but drift in one of the eight monitoring system sensors. The sensor was recalibrated and the monitoring system determined to be functioning properly. The gas distribution system was recharged with hydrogen and verified as 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

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 health physics technician (HPT) discovered that a scaler in an analytical laboratory was out of P-10 gas (90%Ar and 10% CH4). The HPT went to the building where auxiliary gas cylinders are stored. He located a P-10 gas cylinder and turned to search for a hand-cart. There were no hand-carts present, and the technician had to get one from another room. When he returned to the cylinder storage area, he loaded the wrong cylinder. It contained hydrogen gas instead, however, the two cylinders were next to each other and they were basically identical. The empty cylinder was then replaced by the full one and the scaler was purged for several minutes before it was used. The alpha channel worked well, however, the beta channel did not respond. An instrument technician was contacted to identify view more

A liquid hydrogen neutron moderator developed a leak between the canister that contains liquid hydrogen and the insulating vacuum jacket.

The moderator assembly consists of an exterior metal vacuum jacket with an interior metal transfer line and canister that contain liquid hydrogen. The moderator canister is constructed of aluminum and is approximately five inches wide, five inches high, and two inches deep. The liquid hydrogen supply lines to the moderator canister are constructed of stainless steel. The operating temperature of the moderator varies from -420 degrees Fahrenheit to a possible 300 degrees Fahrenheit. Mechanical operators discovered a leak following a cleaning operation on the moderator. The cleaning operation was performed to remove impurities that could freeze view more

During a facility walk-through, it was noted that a combustible gas (hydrogen) monitoring system installed in a furnace room was inoperable (the system had been unplugged). This system is used to detect and warn facility employees of an explosive or flammable environment. An explosive or flammable environment can only occur if there is a leak in the system, which would not be expected to occur during normal operations. When the system was reactivated, no leaks were indicated.

The incident had the following three causes:

A procedure describing administrative controls necessary to ensure safe operations in the area should have been developed and implemented prior to disabling the hydrogen monitoring system.
The hydrogen monitor was not hard-wired, which allowed it 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

A routine security patrol reported a strong odor of sulfur coming from a battery charging facility. The battery charging facility is used for charging the various forklift batteries for the shipping and receiving operation. The building is approximately 450 sq. ft. and has four charging stations. Emergency response was initiated and the incident commander responded to the scene. Initial air monitoring indicated readings above the Lower Explosive Limit (LEL) for hydrogen gas. The local fire department responded and setup for the situation. Facilities personnel responded and turned power off to the building. The building was ventilated and verified to be safe by the fire department. There were no injuries or damage.

The exhaust fan for the building failed, allowing hydrogen gas to view more