The accident occurred at a production, distribution and storage station for hydrogen city busses. After filling the hydrogen cylinders of a bus, the hydrogen detection system of the bus triggered an alarm. The site technician pushed the emergency button and the station was put in safety mode. The technician in charge of filling disconnected the hydrogen hose that connects the station to the bus. The maintenance manager of the bus manufacturer was alerted and arrived 20 minutes later and evacuated the personnel. They closed the valves of the on-board storage system.

A fire developed on a tube trailer transporting 330 kg of compressed hydrogen, while travelling on a highway. The fire was due to a pressure relief valve of a tube releasing hydrogen. The flames reached 10 to 20 m. The fire brigades were able to extinguish the file in 30 minutes.The truck had left a plant of hydrogen production and storage to deliver to a refuelling station. The probable origin of the incident is a fire on the tyres of the truck, which caused the overheating of the tubes, the increase of the internal pressure and the consequent opening of the pressure relief valve.

During the shipments of incinerator bottom ash, flammable gasses including hydrogen generated and caused two explosions. The first explosion was in the forecastle store and the second in the cargo hold.The vessel was loaded with a cargo of 2333 tonnes of unprocessed incinerator bottom ash. The chief engineer, who was inside the forecastle store at the time, suffered second degree burns and was airlifted to a nearby hospital.

The safety cabinet with compressed hydrogen was located in a laboratory and used to supply hydrogen to an experimental facility. The safety cabinet was equipped with exhaust extraction. Due to a leak, technical assistance had been requested from the fire department. The head of laboratory shut off the electrical supply to the laboratory. Measurements showed that there was no potentially explosive atmosphere in the laboratory room.

The event occurred at manhole cover of a of a pilot plant reactor where hydrogenation had been performed in a hydrochloric aqueous solution. The reactor had been flushed three times with nitrogen (i.e. nitrogen injecting at 3.2 bars and then relieving). An employee opened the manhole cover of the reactor to take a sample of the reagent. . After opening it, a minor detonation occurred.According to the DECHEMA database, the investigations found out these following causes:1.

An explosion and fire occurred at a 3000-gallon (approx. 11400 l) reactor, part of the production process of linear alkyl benzene (LAB), Process materials released from the various vessels and piping fuelled a subsequent fire that took approximately 2 hours to extinguish.As reported by Ali Reza (Ali Reza et al., 2007, see References), before the explosion, the bottom of the reactor was plugged with approximately 180 gallons (approx. 800 l) of a sludge-like mixture of coarse aluminum powder, aluminum chloride and various hydrocarbons.

The event occurred at one of the unit producing iron powder, consisting of a furnace with a running belt for the powder, kept under hydrogen atmosphere to reduce and purify the metal. The hydrogen was supplied to the furnace through a pipeline running in a trench below the furnace. A corroded section of this pipeline released hydrogen which could cumulated in the covered trench for at least 30 before igniting. The following hydrogen explosion projected into the atmosphere a large quantity of iron dust, which also ignited.

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.

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.

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.