The event occurred at a hydrogen tank, causing a flare and a displacement of air that threw the contract workers against the refinery's metal structure.The workers were using an electric rotary sander on the inside the tank which had been had been drained three days before. The workers had already done previously the same work without incident.

The event occurred in a bus garage when carrying out the purging process of the hydrogen cylinders. This process was executed via an electronic control system, but it was found that one cylinder solenoid valve was mechanically stuck. In these cases, the valve manufacturer has foreseen an alternative manual process using an override tool. The process was executed according to manufacturers instruction, but the valve did not start to evacuate hydrogen when expected. The fuel cell engineer tried to rectify the problem and started removing the override tool, but forgot to unwind the stem.

A 50-litre standard hydrogen gas cylinder was temporarily placed and used in a laboratory. The hydrogen gas was used for a flame ionization detector (FID) in gas chromatography (GC) instrument. The safety relief valve on the pressure regulator blew open and released of about 340 g of hydrogen into a laboratory. The gas cloud did not ignite so there was no injury or damage. In Henriksen et al (see references) a full investigation is presented to verify the cause of leakage and estimate the gas concentration of the dispersion and gas cloud, including the modelling of a likely explosion.

Release from a compressed storage of an optics component plant The leak was observed on the hydrogen storage consisting of 19 racks of 16 cylinders each. Rescue teams set up a security perimeter and a specialized company inspected the leak.The activity of the establishment were interrupted during the night and resumed the next morning.

A hydrogen leak occurs at a gas cylinder storage tank park in a nuclear power plant. Employees locate the origin of the leak on a defective pressure regulator. They isolate the hydrogen release and secure the park. 10 m of gas, the equivalent of one and a half cylinders, escaped.

Following a loss of power the failure of a backup battery causes an alarm in a hydrogen storage facility. Consequently, a valve on the purge circuit and 30 m3 of hydrogen is released to the atmosphere.

The event early on a Saturday morning, when the plant was thus practically empty. Nevertheless, the chronology of the accident can be reconstructed from the testimonies of the few operators who were present at the time:Phase 1: Gas leak - Loud whistling from the hydrogen storage facility could be heard , lasting 20 to 40 seconds.Phase 2: Explosion - The released hydrogen cloud ignites. A very bright, red-orange fireball measuring 15 to 20 m in diameter was visible for 3 minutes. Witnesses in a common room, located 100 m away from the pit, felt the shock wave and the heat from the blast.

The accident took place when replacing a pallet of empty hydrogen cylinders with a new full one. The pallet in service (almost empty) was not disconnected from the gas supply line. When the operator in charge of handling (fork lift) begun to remove the pallet in service from its position, he teared off the hose connecting it to the pressure relief system. The pressurised hydrogen in the pipes and in the pallet escaped and ignited. The intervention of the teams from the plant and external emergency services extinguished the fire in 1h45.

A major leak (estimated between 1.5 and 3 kg) of hydrogen from high-pressure storage, resulted in a detonation, from hydrogen a refuelling station.Causes were two untightened bolts securing the gasket between the high-pressure tank and the pipeline.

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.