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

While research staff were working in a lab, a staff member opened the primary valve to a 0.2" (1500 psi) hydrogen gas line connected to a manifold supplying instruments in the lab. Upon opening the valve, the hydrogen gas line failed at a fitting on the switching manifold, releasing a small amount of hydrogen gas. The staff member closed the valve immediately, then inspected the gas line and found the front ferrule (of the compression-style fitting) to be missing. There were no injuries or damage to equipment.

In the follow-on discussion with research staff, it was learned that approximately one month earlier, a similar condition (front ferrule missing from a fitting) was found while performing a modification to a similar manifold. Following a critique, management expressed view more

A deficiency was discovered in the application of a hydrogen sensor in the Rotary Mode Core Sampling (RMCS) portable exhauster. The sensor is installed in the flow stream of the exhauster designed to be used with a RMCS truck for core sampling of watch list tanks, and is part of the flammable gas detector system. During the previous week, a quarterly calibration of the sensor, per maintenance procedure, was attempted by Characterization Project Operations (CPO) technicians. Ambient temperatures during the sensor calibration were approximately 20 to 30 degrees F. Inconsistencies in calibration results and the failure of the sensor to meet the response-time calibration requirement lead to the conclusion that the unit could not reliably perform its safety function at low ambient view more

An operator went to purge a process tank per standard operating procedure. The operator reviewed the previous shift's purge time and determined the next required purge time. The operator found that the tank had been purged earlier than expected on the previous shift. Because the earlier purge time was not recognized, the 12-hour purge frequency was exceeded.

Background: On the previous day, during the night shift, an operator performed 12-hour hydrogen purges per the requirements of the standard operating procedure. Each of the hydrogen purges was completed within the required time limits. The operator correctly recorded the time and date that the next hydrogen purges would be required. The following morning, shift turnover was conducted. The direct and root cause of this view more

A demolition technician noted an elevated combustible gas lower explosive limit (LEL) on a pipe that was being tested prior to cutting (No. 2 pipe). The No. 2 pipe was one of four pipes being tested. The other three pipes tested less than detectable for combustible hydrogen gas. Testing involves tapping the pipe and connecting the pipe to an Explosive Gas Detector via a tube. When an elevated LEL is identified, the pipe is allowed to vent and then retested prior to cutting. After tapping the No. 2 pipe, the work crew left the pipe open to vent and departed the area for the end of shift.

At approximately 7"45 PM on the same day, a crew was on overtime to support roofing activities. Since additional workers were available, the craft supervisor decided to re-enter the viewing view more

One morning a saltwell pump was placed in operation. Operation of this equipment requires that the Standard Hydrogen Monitoring System (SHMS) cabinet be in operation. Later that morning, during the morning surveillance rounds, the Standard Hydrogen Monitoring System (SHMS) cabinet was found not to be in the operational mode.

On the previous day, the night shift saltwell operator assigned to run the saltwell pump had placed the SHMS monitor in operational mode; however, the saltwell system was not started at this time. Shift turnover was conducted and the condition of the SHMS was turned over to the appropriate saltwell operator and shift manager. During the day shift the day shift operator assigned to the complex received approval from the operations engineer to place the SHMS view more

A facility representative observed pipe-fitters enter a containment tent around a riser with a tool bag that contained a mixture of steel and copper/beryllium tools. The top flange was loosened using a copper/beryllium socket and a steel torque wrench. When questioned, the pipe-fitters correctly stated that this was allowable for initial loosening and tightening of these bolts. A copper/beryllium ratchet was used to accomplish the bolt removal. The bonded riser was shifted to allow access for the IH technician. The standard hydrogen monitoring system (SHMS) cabinet and local sample showed no hydrogen/flammable gas was present.

While the continuous vapor sample was being taken, the pipe-fitters proceeded to put together the copper/beryllium ratchet and socket with a 10" 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

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 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