A leak occurred at a of a liquid withdrawal valve of a liquid hydrogen storage tank. The hydrogen escaped at the flange between the valve body and the upper part of the valve (flange with tongue and groove). 40 kg of hydrogen were lost.The accidental release was due to the use of bolts different from those prescribed. By using the wrong ones (old bolts), the bolt material was able to flow at the specified tighteningtorque. This meant that there was insufficient tightening torque, which led to a leak.

The event occurred at the hydrogenation unit of a pharamceutical company. 145 kg of hydrogen were released the atmosphere at the gas circulation pump, due to a maintenance error . A specialist company (third-party company), had replaced the cylinder head of pump, but during assembly they did not re-isntalled the prescribed temperature sleeve for the thermometer (the temperature sleeve is the pressure-bearing element).

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 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.

The incident occurred at company producing specialised products for aerospace and aeropwer applications. An employee was operating an induction brazing machine under hydrogen atmosphere when an explosion occurred.

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.

A fire broke out following a hydrogen leak on the cyclododecane unit in a chemical plant. A plume of smoke became visible outside the site. The fire was brought under control by putttng the unit in safe mode, implementing the internal resources available on site (monitor lance, sprinkler ring and extinguishers), and finally by the inervention of the internal firefighters. The staff was evacuated and the internal crisis unit triggered. The fire was extinguished in 30 minutes. The post-incident analysis revealed a hole in the connection of the vent manifold, upstream of the evacuation pipe.

A fire broke out on the insulating plastic elements of an alkaline electrolyzer in a unit of a chemical plant. The shift saw the smoke from the control room. The first action was to drain the potash into a tank provided for this purpose and to shut down the electrolyzer. The on-call electrician interrupted the electricity. The safety technician brought the fire under control in less than 10 minutes using CO2 extinguishers. After approximately six hours, the unit is restarted.

a gas leakage (approximately 70% hydrogen, 21% nitrogen and the rest carbon monoxide and other impurities) occurred at the connection between a temperature measurement casing and a flange in the carbonization workshop cleaning tower. The leakage was reported to the plant leader, who issued the request to the workers to use iron cards and rubber plates to plug the leak. The operation failed and the leakage continued. At 17:00, at the request of the plant leader, the workers used a tire inner tube to wrap the leak.

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.