The vessel affected by the incident was a gas storage used for the desulfurisation process. The desulfurization gas had high hydrogen content. The vessels had cracks in the upper transverse fillet welds at the gas inlet which caused low stress brittle fractures. The cracks had been found during the maintenance, but not fixed. This eventually caused a gas release. Approximately 2.5 hours after that a leak was detected and reported, a first explosion occurred.

The incident affected the raw material buffer tank (design pressure 0.38 MPa) of a diesel hydrogenation unit in a refinery. This buffer tank is located between the hydrogenation reactor and the raw material storage tank. During pressure fluctuations in the lubricating oil system of a hydrogen compressor, the operator handled the situation improperly, resulting in an abnormal shutdown of the compressor, causing the hydrogen feed pump to interlock and stop.After the pump interlocked, the outlet valve was not closed in time and the two check valves failed.

The incident occurred at a power generator during the shutdown of one reactor unit. Hydrogen leaked from the cooling circuit of the generator due to damaged sealing. The hydrogen ignited. The fire was extinguished after 1 hour 40 minutes.

The incident occurred in a catalytic reforming unit. At 13:41, a leak occurred at the 90 elbow of a pressure pipe containing a mixture of hydrogen and naphtha. This pipe was located between the pre-hydrogenation heat exchanger and the pre-hydrogenation product tower heat exchanger. The flammable material leaking from the pipe burst into flames, and at 13:51 and 14:21 there were two more explosive combustions.

In a residual-oil hydrotreatment unit (also called residual oil hydrogenation) plant, a hydrogenation unit caught fire with a huge bang, followed by a fireball in the form of a mushroom cloud. Black smoke began to billow up in the sky and was clearly visible from several kilometres away

A pick-up truck pulling a trailer carrying compressed hydrogen crashed in Ohio yesterday. The hydrogen leaked and ignited, producing flames ten metres into the air. The hydrogen quantity transported was 450 kg.

An explosion of unknown cause occurred at a hydrogen manufacturing plant. The explosion occurred on the second floor of the building, used by employees as a cafeteria and offices. The company where the accident occurred mainly produces industrial hydrogen gas and supplies it in cylinders and trailers, as well as through pipe-line. The building was damaged and three people were seriously injured. The explosion shook the ground and caused nearby workers to evacuate.

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.

The incident consisted of a leakage of potassium hydroxide solution (KOH) from an alkaline electrolyzer in a renewable hydrogen production plant. One webpage news reported that smoke formation triggered the fire alarm system. According to the manufacturer, the equipment shut down and automatically went into safety mode in accordance with the integrated safety system.Nobody was injured in the event and there was no damage on the environment.

While filling a 9 litre gas cylinder with pressurised hydrogen in the hydrogen storage area, a blast occurred which destroyed the low pressure gauge, followed by a jet fire which damaged the surface of the cylinder.The cylinder to be filled, including pressure gauge and control system, had been provided by a third party. Its nominal pressure was 35 MPa, however the maximal pressure of this filling would have been much lower, less than 20 MPa, corresponding to the maximal pressure of the bulk storage available.