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.

In a refinery, a fire occurred at a new reactor for the vacuum distillate hydro-desulfurization unit. Internal gas (hydrogen, hydrocarbon, etc.) blew from a flange of upper piping in the reactor. It ignited producing 0.5-2 meters high flames.

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 event occurred in a desulfurisation unit for heavy oil (hydro-cracking, Isomax process). The hydrogen release took place from one of the heat exchanges, after the restart of the unit. The reason for the shutdown was for replacing the catalyst. A metallic ring of 1,42 m diameter previously deformed by during maintenance and by thermal cycling, was projected to more than 100 m distance. The hydrogen and the heavy oil contained in the pipe were expelled and exploded immediately, followed by a general fire on the unit.

A triangle flask exploded during a science-class experiment where diluted hydrochloric acid was made to react with zinc to generate hydrogen, at a junior high school. Injures were caused by glass debris flown, five very lightly injured pupils were sent to hospital. Probably hydrogen entered in contact with oxygen because of a wrong experiment procedure, resulting in ignition and explosion.

Electric spark ignited hydrogen in a captive advertising balloon.

Static electricity ignited hydrogen in a rising advertising balloon.

In a chemical plant , a process gas leak (4% ammonia and 88% hydrogen) occurs during a purge operation. The cloud of gas ignites and explodes. An employee is killed.

Ignition of hydrogen produced by washing slag in a tank for chlorosulfonic acid.

Explosion due to injection of hydrogen into a furnace containing residual air.