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.

Several workers sustained minor injuries and millions of dollars worth of equipment was damaged by an explosion after a shaft blew out of a check valve. The valve failure rapidly released a large vapor cloud of hydrogen and hydrocarbon gases which subsequently ignited.Certain types of check and butterfly valves can undergo shaft-disk separation and fail catastrophically or "blow-out," causing toxic and/or flammable gas releases, fires, and vapor cloud explosions. Such failures can occur even when the valves are operated within their design limits of pressure and temperature. Most modern valve designs incorporate features that reduce or eliminate the possibility of shaft blow-out. However, older design check and butterfly valves, especially those with external appendages such view more

An explosion occurred in a Microbiological Anaerobic Chamber of approximately 2 m3 capacity that contained an explosive mixture of hydrogen and air. A fire followed the explosion, but was rapidly extinguished by staff using fire extinguishers prior to the arrival of fire service personnel. The pressure wave from the explosion blew windows out of the laboratory, with glass hitting a passerby on a path outside and glass shards landing up to 30 m away. Ceiling panels were dislodged in the laboratory and adjacent rooms, and a worker using the apparatus at the time was taken to the hospital by ambulance for burn treatment. The worker subsequently fully recovered. Another worker in the lab at the time required medical observation, but was otherwise unharmed.

Mixtures of inert gases view more

An incident involved an explosion of an oven that was heating decaborane for vaporization. In this incident, the heater controller was defective so the heating element was disconnected from the controller and plugged directly into a wall outlet. This situation allowed the oven to reach temperatures in excess of 400 °C within 20 minutes. While the temperature increased, the decaborane continued to expand, causing a significant pressure build-up within the oven. The pressure increase eventually caused the oven's viewing window to burst. A burst of burning hydrogen was emitted from the window and burned the face of a researcher who was hospitalized for approximately three weeks.

A brazing retort in a shop malfunctioned and resulted in an explosion that propelled the retort shell to the roof of the brazing area and then back to the floor. There were no injuries but damage was sustained by the furnace housing and the retort shell.

Administrative personnel were soon on the scene to make a preliminary assessment of the situation. An expert safety team was retained to assist in the investigation of the explosion. The safety team conducted their initial field investigation on the afternoon of the explosion and again on the following day.

Once it was determined that the explosion was the result of an ignition of a flammable mixture of hydrogen and air, the next step was to determine how air ended up in the retort, given that the retort is nominally view more

Summary

A hydrogen generation plant experienced a fire and significant damage due to a concussive combustion event that started in a high-pressure hydrogen feed pipe.

System Description

A certain hydrogen plant is designed to continuously produce hydrogen at a purity of 99.75% and at a rate of 510 m3 per day. Hydrogen is produced in two banks of cells filled with a strong solution of caustic soda. Current is passed through the cells to produce hydrogen and oxygen. The oxygen is vented directly to the atmosphere, while the hydrogen is piped to the gasholder. The gasholder is a low-pressure storage vessel capable of storing 28 m3 of gas. It is constructed in two parts. The bottom section is a large round tank. The upper section is an inverted tank or bell that is view more

Description of Circumstances
An incident occurred in late 2001, while a boiling water reactor (BWR) unit was operating at rated power. The utility was performing a periodic surveillance of the high-pressure coolant-injection (HPCI) system. Immediately after the test began, the HPCI system automatically isolated and the reactor building fire detectors actuated. The unit was then manually shut down. An examination of the residual heat removal (RHR) system revealed that a pipe elbow had ruptured near the high point in the RHR branch steam supply line leading to one of the two RHR heat exchangers (steam condensing mode line) in the reactor building. Fragments from the piping rupture caused some damage to equipment in the general area, but no significant damage to any safety-related view more

A facility experienced a major fire in its Resid Hydrotreater Unit (RHU) that caused millions of dollars in property damage. One employee sustained a minor injury during the emergency unit shutdown and there were no fatalities.

The RHU incident investigation determined that an 8-inch diameter carbon steel elbow inadvertently installed in a high-pressure, high-temperature hydrogen line ruptured after operating for only 3 months. The escaping hydrogen gas from the ruptured elbow quickly ignited.

This incident occurred after a maintenance contractor accidentally replaced an alloy steel elbow with a carbon steel elbow during a scheduled heat exchanger overhaul. The alloy steel elbow was resistant to high-temperature hydrogen attack (HTHA), but the carbon steel elbow was not. view more

Summary

A gas-phase explosion in a storage tower with semichemical pulp at a paper mill has possibly been caused by combustion of a mixture of hydrogen and air. The hydrogen was formed by microorganisms in the pulp. Ignition may be due to electric sparks in connection with an electric field in the mist above the pulp.

Accident Description

A gas-phase explosion took place in a 1,300 m3 storage tower for semichemical pulp at a paper mill. The storage tower was 21 m high and equipped with an agitator at the bottom. By a pumping arrangement, the pulp was circulated from the bottom to the top through external pipes connected with the mill (Fig. 1).

On a given day the production was stopped at a time when the storage tower was loaded with 1,000 m3 pulp at a view more

An explosion occurred in an electrolysis system in a commercial facility. Electrolysis of a potassium hydroxide solution is used to produce hydrogen for a hydrogenation processes. The circular electrolysis cells are 1.5 m in diameter and 25 mm thick. Design current for the electrolyzer is 6,000 amps at 1.78 volts. Operating temperature and pressure is 70-90 °C and 435 psig. Hydrogen and oxygen product gases are separated from the electrolyte in separating drums. The system had been operating at the plant for 13 years prior to the explosion. Operating experiences had been generally favorable except for the need to periodically flush the system with water to remove sludge formations.

According to the investigative report, sludge deposits in the electrolyte passages started the view more

A hydrogen explosion occurred in an Uninterruptible Power Source (UPS) battery room. The explosion blew a 400 ft2 hole in the roof, collapsed numerous walls and ceilings throughout the building, and significantly damaged a large portion of the 50,000 ft2 building. Fortunately, the computer/data center was vacant at the time and there were no injuries.

The facility was formerly a large computer/data center with a battery room and emergency generators. The company vacated the building and moved out the computer equipment; however the battery back-up system was left behind. The ventilation for the battery room appeared to be tied into a hydrogen monitoring system. The hydrogen sensor was in alarm upon emergency responders arriving at the scene (post-explosion). 911 callers view more