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 power plant reported a hydrogen leak inside an auxiliary building. The given plant was in cold shutdown at the time of the event. The discovery of this problem was as a result of an unassociated event involving the activation of a chlorine monitor in the control building. When additional samples indicated no chlorine gas, the shift supervisor ordered further investigation into other plant areas. Because there was no installed detection equipment, portable survey instruments were used to determine gaseous mixtures. Hydrogen was detected in the auxiliary building at 20 to 30 percent of the lower flammability limit (LFL) for hydrogen. A level of about 30 percent of LFL corresponds to about 1.2 percent hydrogen by volume.

When hydrogen was discovered in the auxiliary building, the view more

During an inspection, three potential safety problems were identified concerning the location of a hydrogen storage facility. The hydrogen storage facility is located on a building's roof, which is made of 30-inch-thick reinforced concrete. The following potential safety problems were identified during the inspection:

Leakage of hydrogen gas from the storage facility in proximity to the air intakes of the building's ventilation system may introduce a flammable or explosive gas mixture into the enclosure. Because the hydrogen storage facility, containing four 8,000-scf hydrogen tanks at up to 2,450 psig, is Seismic Category II, a seismic event may result in a hydrogen leak. Furthermore, the pressure relief valves in the hydrogen facility exhaust downward to within 6 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

A shop supervisor determined that a second shift would be necessary to complete some priority work on the spare hydrogen mitigation pump. The work scope for the shift would be dedicated to continued fabrication of designed tubing runs, repairs to existing tubing with known leaks and pressure testing of other various tubing runs. The shift craft complement would include three pipe fitters, one welder, one QC inspector and a shift supervisor.

The shift remained under normal operations prior to the event. There had been no existing problem up until the point that craft personnel implemented some hydrostatic pressure testing on some tubing runs on the spare hydrogen mitigation pump. Work activities associated with the hydrostatic testing were to be in accordance with the Hydrostatic view more

A guest student was weighing out less than 200 mg of sodium hydride. The material reacted with moisture in the air, producing hydrogen. The heat of the reaction ignited the hydrogen on the end of the spatula being used to transfer the material and at the mouth of the bag holding the stock material (approximately 48 to 50 g). The student attempted to smother the flames with a cotton lab coat hanging nearby. He quickly determined that the lab coat was insufficient to smother the flames and entered the adjoining lab to get a fire extinguisher and warn other lab workers in the area. The other lab workers exited the lab, warned others in the area, pulled the fire alarm and called the laboratory shift supervisor. The student extinguished the fire with the fire extinguisher, then left 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

Incident Synopsis

A technician accidentally loosened critical bolts holding a fitting to the top of an H2 tank, which caused a large hydrogen leak in the dewar. The fitting contained various instruments, and upon loosening the third bolt, H2 gas exited through an opening in the seal. The Viton or neoprene O-ring was blown out of its groove and was immediately frozen, making it impossible to reseal the fitting cover. The area was evacuated, the dewar was vented and the gasket was replaced. The ullage space was not purged with helium gas during the gasket replacement, which may have been responsible for small leaks which developed during the transfer.

Cause

The fitting containing the instruments was mounted on a flange, which was in turn secured to another flange. view more

An isolated vehicle hydrogen tank needed to be de-fueled, but the standard operating procedure could not be followed because the tank was inoperable and had to be manually vented with a special tool. This intentional release of hydrogen was done outside an R&D facility, but it unintentionally activated two sensors on vehicle bay gas detectors (at 20% LFL) in the adjacent indoor facility. Although each person involved in this activity was qualified to perform the work, the circumstances at the time were unusual.

The hydrogen fueling dispenser nozzle could not be completely disconnected from the vehicle after refueling. It was finally disconnected after trying several times. The cover of the nozzle interfered with the disconnection operation. No malfunction of the nozzle was found. It can be easily disconnected when it is withdrawn along its axis. Sometimes misalignment occurred due to the weight of the dispenser hose.