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.

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

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 operator began preparations for a cleaning run, and was unaware that a maintenance task to calibrate a pressure transducer was scheduled to also take place that morning. The calibration required a break on a hydrogen line in order to install a Measuring and Test Equipment (M&TE) gage, which was used in the calibration. At the time the operator was informed of the calibration, the cleaning run procedure had been initiated but the actual cleaning had not yet begun. A discussion between his supervisor and the facility maintenance coordinator resulted in a decision to proceed with the maintenance task and suspend the cleaning run until afterwards.

The operator evacuated the hydrogen line and the hydrogen cylinder was valved out. The maintenance work package procedure had view more

A hose clamp failed on a low-pressure vent line from a hydrogen reactor experiment and effluent was leaked into the laboratory. Unburnt hydrogen in the effluent stream triggered the low-level hydrogen alarm. The hose clamp was resecured and other hose clamps were checked for proper tightness.

During a 70-MPa fueling, the fueling hose breakaway separated. The separation occurred without any extraneous forces other than the pressure of the gas internal to the fueling hose. Upon investigation, it was determined the pull force set point was incorrectly adjusted. No further issues or actions.

A hydrogen leak occurred from a 1-inch gate valve on a makeup gas line in an oil refinery gas oil hydrotreater unit. When the leak was discovered, the gas oil hydrotreater unit shutdown procedures were immediately implemented and emergency response was requested. The refinery response team along with county response teams responded, and after approximately 1/2 hour, the gas oil hydrotreater unit was fully shut down. Shutdown consisted of sufficiently depressurizing the unit and adding nitrogen to allow safe closing of the leaking 1-inch gate valve and installation of the associated missing bull plug.

During this event, the 1-inch gate valve was found to be open roughly 10% with no bull plug in the valve, allowing the hydrogen to leak to the atmosphere. In addition, a 1-inch bull view more

A partial pressure sensor for an automated gas environment system (AGES) was not functioning correctly for pure hydrogen flow. While personnel were troubleshooting the problem, a burst disk ruptured resulting in a leak of hydrogen gas and actuation of a flammable gas alarm.

System troubleshooting involved the installation of a small hydrogen gas cylinder and temporary manual valve in an engineered ventilated enclosure adjacent to an instrument sample well. A burst disk associated with the temporary manual valve ruptured upon opening of the gas cylinder valve. The vented gas, exhausting through an engineered exhaust system, triggered the flammable gas detector. Personnel promptly evacuated the area in accordance with established procedures. Appropriate personnel responded to the view more