A 9000 gal (34 m3) LH2 storage tank exploded during repair of the vent stack. Few days before the explosion, the tank had been filled with LH2, but later on the hydrogen released and ignited at the tank pressure control system, damaging the vent stack. To perform the required repairs, the tank had to be emptied. To this purpose the vessel was purged with nitrogen gas to display the LH2 by letting it boiling. However, the pressure inside the vacuum jacket increased because of the opening the vacuum valve. This pressure increase eventually led to the catastrophic tank rupture.

In 1987, well diggers had drilled a well for water, but had given up on one dry borehole at a depth of 108 meters. According to the source reported in the References, wind was coming out of the hole. When one driller peered into the hole while smoking a cigarette, the so-called wind exploded in his face. A huge fire followed, without smoke, looking bluish at daytime and colour and goldish at night. The crew needed weeks before being able to stop the fire and cap the well. The well remained capped until 2007, when well gas was analysed and revealed to consist in hydrogen with a purity of 98%.

This incident occurred at the hydrogen production and storage unit of (probably) a power plant using hydrogen as a coolant of the turbine-generator system. Hydrogen was produced probably by water electrolysis (the source does not say it) and stored in 6 steel tanks. One of the six hydrogen storage tanks exploded killing a staff member. The investigation determined that a mixing of hydrogen and oxygen occurred in the tank. The needle valve of the hydrogen and oxygen pressure regulator as jammed, and the oxygen leaked into the hydrogen main supply line and entered the hydrogen tank.

A gas release occurred in the building for the recirculation of processes gas. The gas was a mixture of hydrogen and nitrogen. It occurred at the outlet valve, during works aiming to replace it. This caused the creation of an explosive gas mixture and the surrounding spaces. The defective valve has been identified several years before, its poor design and ageing caused the gas leakage. The ignition took place with 9 minutes delay after initial leakage.

An explosion of unknown cause occurred at a hydrogen manufacturing plant. The explosion occurred on the second floor of the building, used by employees as a cafeteria and offices. The company where the accident occurred mainly produces industrial hydrogen gas and supplies it in cylinders and trailers, as well as through pipe-line. The building was damaged and three people were seriously injured. The explosion shook the ground and caused nearby workers to evacuate.

This entry refer to a series of events occurred before the date given, which corresponds to the publication of the evidences at the Int. Conference on Hydrogen Safety 2015. The nozzle/receptacle connection froze when refuelling the on-board hydrogen storage system at the lowest precooling temperature of -40 C. However, freezing did not cause apparatus damage nor hydrogen leakage. The nozzle/receptacle is thus able to fuel safely even if the nozzle/receptacle is stuck due to ice.

Hydrogen gas cylinders exploded at the same time in three industrial locations, when the opening valve was opened. The overpressure generated by the explosion caused the walls of the hydrogen cylinder storage room to collapse, six workers were killed. The hydrogen cylinders used by the three companies were filled by the same company.The investigation found that a large amount of air was mixed with hydrogen in many of the delivered cylinders, the air accounting for 50% of the total volume.

The truck overturned and lost vacuum insulation. The hydrogen boiled and vented, but there was no ignition. The potential for fire or explosion, however, led to precautions that did cause considerable disruption: the interstate highway where the accident occurred was closed and nearby homes and businesses were evacuated.

The incident occurred during the verification operation of a new high pressure hydrogen generator. The electrolysis cell burned down, the pipes of the oxygen circuit burst and the peripheral equipment were scattered all over the facilities. The liquid blown out from the broken pipes and the gas release valve, and glass fragments were scattered within a radius of ten meters. There was no injury. The analysis of the incident (Wada et al., ICHS 2007) assumed as probable initiating cause that titanium electrode in the electrolysis cell was exposed to oxygen and burned.

The hydrogen buffer tanks that exploded were part of an experimental facility experimenting generation of renewable hydrogen from a water electrolyzer coupled to solar panels.The three hydrogen tanks (40 m3 capacity each at pressures of 1,2 MPa one of them and 0,7 MPa the two others) were receiving the hydrogen produced by the electrolyzer. Firefighters said all three tanks were destroyed in the explosion; there was no fire, but the explosion was strong enough to send debris being scattered in an area well over 3,000 square meters.