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.

An offgas system mishap involved two explosions occurring within an interval of about 3 ½ hours. The first offgas explosion was reportedly caused by a welding operation on an air line adjacent to a hydrogen sensor line containing off gas. The welding arc initiated a detonation within the offgas piping. The detonation was contained by the piping system but blew out the water seal at the base of the vent stack.The second hydrogen explosion in this incident occurred in the stack base area. Hydrogen accumulated in the enclosed base area after the water seal had been blown in the first explosion. The stack base metal door was blown off its hinges from the second explosion, and the reinforced concrete stack was also damaged. A plant employee walking by the stack at the time of the explosion view more

The over-pressurization of a laboratory ball mill reactor designed for operation under slightly elevated pressures resulted in a serious injury. The apparatus had been routinely operated under argon and hydrogen pressures of 5-10 atmospheres for nearly two years. The apparatus had not been tested for operation at pressures greater than 10 atm.

A visiting intern, frustrated in attempts to hydrogenate magnesium silicide through ball milling in the previously noted pressure range, attempted to perform the operation at higher pressures. The approximately 70-ml reactor was loaded in a glove box with 0.5 g of magnesium silicide and six milling balls. Upon pressurization to 80 atmospheres, a 270-degree rupture occurred around the perimeter of the reactor. The blow-out of the reactor view more

An explosion at a coal-fired power plant killed one person and injured 10 others. The blast killed the delivery truck driver who was unloading compressed hydrogen gas, which is used to cool the plant's steam generators. Hydrogen deliveries are routine at the plant, occurring about once a week. Evidence pointed to the premature failure of a pressure-relief device (PRD) rupture disk, which had been repaired by the vendor six months prior to the explosion.

Operators in a powdered metals production facility heard a hissing noise near one of the plant furnaces and determined that it was a gas leak in the trench below the furnaces. The trench carried hydrogen, nitrogen, and cooling water runoff pipes as well as a vent pipe for the furnaces.

Maintenance personnel presumed that the leak was nonflammable nitrogen because there had recently been a nitrogen piping leak elsewhere in the plant. Using the plant's overhead crane, they removed some of the heavy trench covers. They determined that the leak was in an area that the crane could not reach, so they brought in a forklift with a chain to remove the trench covers in that area.

Eyewitnesses stated that as the first trench cover was wrenched from its position by the forklift view more

The incident occurred in the catalytic hydrotreatment plant of an oil refinery. The plant, which began operations in September 1997, has a capacity of 1650 tons/day of light fuel oil and 1450 tons/day of heavy fuel oil. The plant was designed to desulfurize the light and heavy fuel oil fractions produced in the refinery by treating them with high-pressure hydrogen over a catalyst to remove sulfur (producing hydrogen sulfide as a byproduct). The plant has two heating/reaction/fractionating sections to treat the two fuel oil fractions, but a single gas purification and compression section for the recycled hydrogen gas.

The heavy fuel oil reactor feedstock from the vacuum distillation plant is sent to the heavy fuel oil treatment section through three pipelines equipped with flow view more

A hydrogen explosion and fire occurred in the benzene unit of a styrene plant in a large petrochemical complex. The unit was being restarted following a scheduled maintenance shutdown. The explosion followed the release of about 30 kilograms of 700-psig hydrogen gas from a burst flange into a compressor shed. Two men were killed and two others were injured. If it had not been a holiday, the death toll and injuries would probably have been much worse.

The operators were bringing the plant online and increasing the hydrogen circulation pressure. About 10-15 seconds before the explosion, they heard a pop and then a loud hiss of pressure being released within the compressor shed. Witnesses reported seeing a white flash and then a large fireball. The fires burned out in 2-3 minutes, view more

A researcher was working with hydrogen storage materials in a laboratory. Several other researchers were working in adjacent laboratories.

The researcher had prepared a sample of aluminum deuteride, AlD3, by reacting lithium aluminum deuteride and aluminum chloride in diethyl ether. The actual composition/phase of the material synthesized was unknown, but the researcher had attempted to produce the gamma phase of aluminum deuteride. The synthesis steps used to produce the material were complete and the researcher attempted to seal the material in a glass ampoule for offsite shipment and analysis. The sample size was approximately 1 gram.

The ampoule with the sample had previously been placed under vacuum and had been isolated from the atmosphere. The process for sealing view more