This incident illustrates how difficult it is to completely purge hydrogen out of a large, complex piece of equipment. Uniform mixing and dilution is unlikely in all the partially enclosed spaces, crevices, etc. If a hazardous operation such as…

This incident illustrates the danger of hydrogen being inadvertently released through blown water seals. Similar incidents have occurred in non-nuclear industrial facilities, but offgas systems present a special hazard because of the…

The mechanisms and rates by which hydrogen gas is generated and subsequently accumulated in the holding tank need to be fully understood by vendors and employees alike. Active venting, warning signs, and local alarms designed to activate when…

The above described events are an indication of a potential licensee/vendor interface problem. Based on the information received, the vendor was not completely informed via the purchase specifications regarding the service condition to which the…

This incident highlights the need to properly design safety interlocks. These safety interlocks need to be carefully incorporated into the initial building/plant designs and should consider all of the unexpected occurrences, such as the…

The investigative report noted that the explosion could have been prevented by (among other things) a continuous gas analyzer test of oxygen and hydrogen product purity. The continuous analyzer should be interlocked to shut the electrolyzer down…

These events show the importance of preventing combustible gas mixtures from accumulating in piping. In both of the above described events, hydrogen and oxygen gases apparently accumulated to a combustible level which then catastrophically failed…

Batteries stored on a charger can explode during use if overcharged.

Recommendations

1. Use automatic current limiting or timed circuit chargers when charging batteries.
2. Operators should be aware of safe…

Personnel should be properly supervised, and supervisors should be aware of the activities of their personnel. Personnel must be motivated to adhere to established policies and procedures. All personnel associated with potentially hazardous work…

• Battery power supplies require adequate ventilation for all operations, or the battery box should be designed to:
  • Eliminate all sparking devices
  • Ventilate during charging operations
  • Provide inert gas…

Immediate Corrective Actions

1. Fuel cell test stand was shutdown and sent to manufacturer for investigation.
2. Carbon dioxide fire extinguisher installed in laboratory.
3. Formal process hazard review performed…

In addition to resealing the glove box window, a positive pressure of argon gas was maintained inside the glove box while the course of action was planned. Subsequently, the glove box was cleaned up by specialized hazardous materials personnel…

• A SOP should be developed which prohibits drivers from backing into the fill position.
• As a precautionary measure to mitigate similar events in the future, piping barriers should be installed which protect critical H₂…

• When truck drivers are carrying new trailers, with new load distribution characteristics, they need to exercise caution, especially on hazardous roadways such as the one described in this occurrence. If the trailer stack would have been…

• All tank trailers should have a safely accessible auxiliary shut off valve in case of spills.
• Emergency personnel need to have access to all of the appropriate protective clothing, including shoes. Liquid hydrogen is stored at 20…

The use of inerting gas or other means of separation should be employed when conducting mechanical work where hydrogen gas could be present. More importantly, per CGA S1.3, the vessel should be equipped with a dual relief system that can isolate…

Extra caution should be taken working around elevated pressure or low-temperature fluids and storage. Values should be checked and then verified by a second party, if possible.

All valves and connectors should be clearly labeled to minimize chances for mis-connection. All technicians must be trained on proper procedures for both taking systems offline and bringing them back online.

Valves for compressed hydrogen…

First, it appears that the system may not have been vented properly. CGA G-5.5 should be used for determining safe locations based on the variables of the specific setup. Also, if the compressor was tied to a storage system, a backflow prevention…

Because of the near invisibility of a hydrogen flame in daylight and hydrogen's extremely low ignition coefficient, if a known leak is present (e.g., an audible hissing), ignition should always be presumed. The primary cause of this incident…