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.

A diesel and gas leak (H2, H2S, CH4) occurred in a hydrodesulfurization unit (2,200 t/d). The leak location was on one of the boiler valves of the stabilization column. The released mixture (390 C / 35 bar) ignited, and due to the heat developed also other valves started leaking. The compressor was stopped and the column isolated. The fire was extinguished in 35 minutes.

Heavy rains (more than 600 mm in 1 day) had flood a factory manufacturing calcium core electrical conductors. The power supply was cut off. The water came into contact with the calcium stored in 150 kg containers, producing hydrogen (7.5 kg per container). The heat of reaction ignited the gas. The fire was extinguished with sand.

A gaseous mixture of hydrogen (H2), methane (CH4) and ethane (CH3-CH3) at 54 bar was cooled in a heat exchanger upstream of a hydrogen purification system. The accident started with a double explosion followed by a fire.The heater used to regenerate the adsorbent beds of the purification unit had been repaired a few hours earlier, but the automatic heating mode had not been activated upon restart. Therefore, two regeneration cycles had been carried out cold, causing an overload of the adsorber and the fouling of the heat exchanger.

A hydrogen leak occurred on the hydrogen line of a hydro-desulfurization unit, followed by ignition . The failure was located on a supply manifold of the unit at a support beam. The unit was shut down.The accident was caused by external corrosion which had developed at a support point, under the pipe insulation. A regular thinning of the piping was observed over a length of 450 mm on the lower semi-circumference. The maximum thickness loss was 6.5 mm. The mechanical analysis concluded that the operating pressure was sufficient to cause this initial failure in the weakened area.

Hydrogen leaked from an analyser and ignited .On-site staff isolate the leak. As the leak was very quickly isolated, the amount of hydrogen released was negligible. Event no. 35501 of the French database ARIA (accessed December 2020) https://www.aria.developpement-durable.gouv.fr/accident/35501/

Hydrogen leaked and ignited on a cell in the sodium chlorate (NaClO3) workshop of a chlorinated products plant.There were no victims and no damage to the environment. On-site firefighters controlled the start of the fire in 10 minutes.

The event occurred on vent stack of an ammonia synthesis unit. The release of the gas was more specifically on the water purge line or the hydraulic guard of the vet stack. The process gas consisting in 75% hydrogen, ignited. The fire could be extinguished the by the emergency decompression of the unit and the automatic shutdown of the synthetic gas turbocharger.

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.

The event occurred in a silicon hydride (SiH) emulsion production process inside an enclosed production building. The process generated a flammable gas cloud gas ignited, which later ignited causing an explosion and fire.The explosion caused four fatalities and one injured worker, heavily damaged the production building and its force was felt up to 20 miles away. According to the CSB preliminary report, various investigations are still ongoing to understand in details the sequence of events of this accident.