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.

[NOTE: the attribution to hydrogen formation as cause of the explosion is 'probable 'but not fully demonstrated].Two explosions in two different sprinkler systems occurred, wit the same assumed cause.The first occurred at the premises of a company, where a service engineer was injured, even though the explosion actually moved out into the open air. The second occurred in the department store, where an installation contractor was burned because an explosion occurred in a large pressure storage tank in a small room with the result that the explosion was particularly powerful.

A hydrogen car caught fire at a hydrogen fuelling station. During refuelling of a H2-fueled car the owner heard an abnormal noise and opened the fuel filler door to investigate. A small fire then occurred after the owner discharged static electricity when making contact with the fuelling cap. Fortunately, the fire suppression system of the refuelling station quickly extinguished the blaze.An analysis of this incident revealed that material from the fuel inlet receptacle filter detached shortly after fuelling was completed.

The tanker truck was carrying nearly 13,000 gallons of liquid hydrogen. it hit the base of a light pole in the parking lot of a local grocery store as the driver was attempting to turn around. Hydrogen gas then began leaking out of it. This resulted in a valve on the truck to become damaged and could have caused the liquid hydrogen to be released from the truck, a very serious situation for nearby residents and businesses. Nobody was physically harmed by the incident.

The leak occurred at the hydro-isomerisation unit of a refinery. Following the observation of a pressure drop between two heat exchangers, controls were carried out on site. A noise was heard, but no gas detection was activated on the unit. A hydrogen leak was detected but the source was not identified. Following the detection of hydrogen, the access to the unit was forbidden and emergency services and the fire department alerted. The unit was decompressed using the safety flare. When the pressure was sufficiently reduced, two operators looked for the origin of the leak.

During a work tour on a refinery, an employee noticed a fire at the level of a flange at the inlet of the grille of an exchanger, located at the outlet of a reactor of the catalytic reforming unit.The plant operator detected a lack of uniformity of torque on the bolts. Two years ago, during a shutdown period, some parts of the exchanger had been removed for inspection. The flange on the heat exchanger side was not easily accessible. On reassembly, the presence of a pipe tee near the flange made it difficult to tighten with a bolting machine.

The accident occurred at a distillate dewaxing Unit (MDDW) of the refinery, during the operation of regeneration of the catalyst. To perform this operation, both temperature and pressure have to be increased. After approximately six hours after having reached the correct regeneration conditions, the 10 inches pipe at the bottom to one of the two reactor experienced a guillotine break, and hot gas was released from both ends. The gas released consisted of 81% of hydrogen, 9.5% of methane and some light hydrocarbons. It rapidly ignited (0.7 sec), causing an explosion.

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.

The station was storing 6,000 litres of liquid hydrogen in ten tanks. Rescue services were alerted and the station's activity is interrupted. The leak was stopped by closing the valves. According to the H2Tools report (see references), a vehicle fill had depleted the high-pressure hydrogen inventory. Consequently, the compressor turned on to refill the storage by compressing 4 bar (60 psig) hydrogen from a liquid hydrogen tank up to the 380 bar (5500 psig) compressed storage tank. After running about 2 hours, a crankshaft bearing started to fail.

Employees were trying to open the manhole cover (600 mm diameter) of a hydrofluoric acid tank with a grinder, when an explosion occurred. The explosion was probably caused by the presence of hydrogen formed by the acid attack of the metal.