Lessons Learned

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 fire erupted from a tanker truck delivering liquid hydrogen to a factory. The ignition of leaking vapors created a plume of flames that rose dozens of feet into the air. The flames receded within seconds, leaving the truck with little damage and its driver unharmed. The truck was off-loading hydrogen into a tank behind the plant when the incident occurred. The plant reported no delays in its production. It uses the hydrogen in various processes. On site personnel reported that hydrogen vapors released through a vent in the tank somehow ignited. The driver sealed off the vent within seconds and stopped the blaze. Fire officials and the two companies are now trying to determine what sparked the vapors. The safety equipment in place prevented the fire from spreading into the tanks. Neither...
A plume of hydrogen gas escaped from the offloading valve of a liquid hydrogen delivery truck while transporting hydrogen to a commercial facility. The plume ignited, resulting in a flash and concussion loud enough to be heard inside the nearby building and to set off the building’s seismic event detectors. A small amount of hydrogen gas continued to escape from the trailer tank and burn until a company specialist arrived to manually shut off a critical valve almost eight hours later. In the mean time, emergency response crews called to the scene sprayed water across the hydrogen tank as a precautionary cooling measure. The actual cause of this incident appears to have been primarily driver error. A number of steps required as part of the standard safety procedure were either incorrectly...
A pinhole at the base of a hand-held hydrogen torch, allowed hydrogen to leak. In the process of lighting a second torch, the leaking hydrogen was ignited. The operator, being startled by the "pop" of the lighted hydrogen allowed the #2 torch to drop and hang by its hose support approximately 6" from the floor. The hydrogen and oxygen hoses on the #1 torch were burned through and hung approximately 12" from the floor. The free burning #1 hose burned the #2 hydrogen and oxygen hose assembly through, causing both hoses assemblies to burn without valve control. The hose size is 1/4" and is used in various areas of the plant.
A facility replaced the copper tubing used for hydrogen distribution, with stainless steel tubing. This was done to address a fire protection concern related to the solder on the copper tubing being susceptible to heat, melting, and releasing a flammable gas. The facility maintenance personnel completed the replacement, noted the pressure on the hydrogen bottle, and left the building. When the maintenance person returned on the following day, s/he noticed the pressure on the hydrogen bottle had dropped 500 psi overnight, indicating a leak in the system. S/he notified the appropriate facility personnel and together they began to determine why the hydrogen had dropped 500 psi overnight. The hydrogen line originates at a manifold, which is part of a glove box atmosphere purification system...
While attempting to light the hydrogen flare inside a Metalorganic Chemical Vapor Deposition (MOCVD) system burn box, a small explosion occurred, blowing the back section of the burn box off. Hydrogen flow was shut down immediately, and this MOCVD operation was suspended. Researchers made the determination that this was a minor incident and there were no injuries. The follow-up investigation determined that the MOCVD HEPA filter had become sufficiently loaded to the point where performance of the burn box exhaust ventilation system was significantly degraded. The static pressure created across the "loaded" HEPA filter equaled the operating static pressure of the exhaust ventilation system servicing the burn box. This resulted in a region of "dead air" in the burn box. Thus, without...
An apprentice mechanic lacerated his right forearm while quickly sliding out from under a hydrogen prototype bus when the bus slipped off a hydraulic jack. The apprentice and another mechanic had raised the bus about 1 foot from the ground to position it on jack stands when the hydraulic jack tipped over. The apprentice went to the site medical facility, where he needed five stitches to close the wound in his forearm. The mechanics were raising the rear of a hydrogen prototype bus, like the one in the figure below, and placing it on jack stands. After chocking the wheels, they used bottle jacks on each side of the rear axle to raise the bus high enough to place a 20-ton hydraulic jack under the differential. With the bus resting on a pair of small jack stands, they raised the bus by the...
A 2000-psia-rated gas cylinder (nominal size 10"x1 1/2") was being filled with hydrogen to a target pressure of 1500 psia. The cylinder suffered a failure at an indicated pressure of 1500 psia during filling. Investigation of the failure subsequently revealed that a faulty digital readout had allowed the cylinder to be over-pressurized. There were no safety consequences due to the failure and no damage to the facility or equipment. The cylinder was being filled in a test vault that was specially designed for the high-pressure burst testing of pressure vessels and components. While no over-pressure cylinders were released from the laboratory for use, this incident is being reported to address the potential and subsequent lessons learned. Investigations revealed that the pressure transducer...
While filling a sample cylinder with compressed hydrogen gas, a quick-disconnect coupler fitting came loose within a stainless steel laboratory hood, allowing a small purge of the hydrogen gas to escape directly into the hood through ~1/4-inch Tygon tubing. The stainless steel quick-disconnect fitting struck the stainless steel bottom of the laboratory hood and the hydrogen gas caught fire. It is not known what caused the hydrogen gas to catch fire. The most likely sources of a spark was from metal-to-metal contact of the quick-disconnect fitting with the laboratory hood floor, or the discharge of static electrical charge generated by flow of hydrogen gas through Tygon tubing. The resultant narrow jet of fire, directed toward the left side of the laboratory hood, extinguished itself...
While refilling the hydrogen system after an outage caused by a power failure, the excess flow valve located at the hydrogen tank tripped, but did not go fully shut. The large valve is equipped with a small bypass valve so that the valve can be pressurized on both sides as is required before the valve can be reset. The O-ring which makes this small valve gas tight was deformed and improperly seated, thus allowing gas to flow to each side of the large valve. This permitted the valve to trip normally, but not to seat properly. The following is the manufacturer's evaluation after disassembly and inspection of the valve. This valve was recently installed to provide excess flow protection to the underground portion of the hydrogen system piping and to provide redundant protection to the entire...
A hydrogen gas detector on the ground floor of a building registered the release of a small amount of hydrogen gas and actuated automatic alarms both at the fire department and in one of its buildings. Additionally, interlocks connected to the gas detector completely shut down the experiment. Upon hearing the alarm, all occupants (about 6) promptly left the building. Fire department personnel are housed in the trailer next to a building and responded within one minute. They tested the atmosphere within the building, reset the gas detector, and secured the alarm at 9:15. The alarm was actuated when an experimenter assigned to the experiment was evacuating lines using a vacuum pump. The speed of evacuation was controlled by a commercially manufactured flow meter. It is believed that the 0-...