This event occurred when a hydrogen-carrying trailer was supplying hydrogen to a chemical plant. Instead of filling the hydrogen stationary storage, large quantities of hydrogen were transferred from the trailer into the compressed air plant network. The explosive atmosphere ignited in a compressed air consumer (a solid silo which was not containing hazardous materials).

The fire developed on a hydrogen bus during filling, and was detected due to the development of smoke and a smell of burned materials.The power cable of the compressor had overheated. Two are the possible causes: (1) the cable had been wrongly installed or fixed, or (2) the electrical system had caused too high current in the cable. The corrective actions have been:(a) To ship the affected component to the manufacturing company for inspection(b) To replacement of the affected component with a new one. (c) To perform an inspection of the system on all the other buses in function.

The accidental hydrogen release occurred when testing the storage system connected to a PEM electrolyzer. The leak test consisted in filling the storage with hydrogen at step-wise increase of pressure. After the step at 3 bar (0.3 MPa), which did not reveal any leak, the storage was pressurised up to 5 bar (0.5 MPa). At that moment a hissing sound occurred from the storage at the outside of the building indicating a leak.

A lightning strike caused a voltage drop on the power supply of a chlorine-alkali plant using the mercury process.The emergency electrical system was activated, though restoring the external supply voltage in less than 200 ms rendered the entire system inconsistent; some units were operating normally, but all units connected to the emergency devices (including the mercury pump) remained idle. An explosive mix of 500 kg of chlorine and an unknown amount of hydrogen accumulated inside the low-pressure chlorine treatment circuit.

The broke out at a hydrogen compressor of the reforming unit of the refinery. Following the safety procedures, the emergency stop of the unit was activated and the unit was decompressed using a safety flare. The emergency plan was kept for an hour. A security perimeter is in place. The isolation of the compressor was started automatically. The isolation of the discharge circuit was successful, but the suction circuit could only be partially closed due to a block of a valve. The operators then closed manually the suction valve, by removing the excess of grease that had been applied to it.

A fire broke out on a transformer transforming 225,000 V into 15,000 V in a metallurgical plant. This transformer supplies electrical power the site and to a neighbouring factory. In the following three hours, staff brought the fire under control with CO2 extinguishers, the internal emergency plan was activated, and the firefighters ventilated the premises and took readings of the flames using a thermal camera. Meanwhile, however, the shutdown of the electrical installation caused the stop of the operation of an electrolysis unit using zinc sulphate.

Release from a welding of a hydrogen transmission pipeline At 12:45 pm the operation control centre (OCC) recognised that a customer flow and pressure dropped significantly. At 13:28 the OCC made the decision to close the upstream remote operated valve. At 15:00 the pipeline technician arrived on site and confirmed the breach in the pipeline. Additional pipeline operations technicians were deployed to isolate both manual block valve upstream and downstream of the incident site.

A hydrogen release and subsequent fire occurred at meter station of a pipeline transporting hydrogen to a refinery. Local refinery emergency response team responded and secured the area. The pipeline was isolated, and the fire extinguished itself. During a winter storm, the area was experiencing abnormal freezing conditions and widespread power outages were occurring. As a result, third party hydrogen supply to the refinery was reduced. These upsets resulted in the need to export larger than normal flow rates on the hydrogen pipeline.

This incident occurred at the hydrogen production and storage unit of (probably) a power plant using hydrogen as a coolant of the turbine-generator system. Hydrogen was produced probably by water electrolysis (the source does not say it) and stored in 6 steel tanks. One of the six hydrogen storage tanks exploded killing a staff member. The investigation determined that a mixing of hydrogen and oxygen occurred in the tank. The needle valve of the hydrogen and oxygen pressure regulator as jammed, and the oxygen leaked into the hydrogen main supply line and entered the hydrogen tank.

A gas release occurred in the building for the recirculation of processes gas. The gas was a mixture of hydrogen and nitrogen. It occurred at the outlet valve, during works aiming to replace it. This caused the creation of an explosive gas mixture and the surrounding spaces. The defective valve has been identified several years before, its poor design and ageing caused the gas leakage. The ignition took place with 9 minutes delay after initial leakage.