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).

In 1987, well diggers had drilled a well for water, but had given up on one dry borehole at a depth of 108 meters. According to the source reported in the References, wind was coming out of the hole. When one driller peered into the hole while smoking a cigarette, the so-called wind exploded in his face. A huge fire followed, without smoke, looking bluish at daytime and colour and goldish at night. The crew needed weeks before being able to stop the fire and cap the well. The well remained capped until 2007, when well gas was analysed and revealed to consist in hydrogen with a purity of 98%.

Around 4 a.m., a major leak occurred at the outlet of the diesel hydrodesulfurization furnace in a refinery. The goal of this unit is to lower the sulfur content of diesel fuels produced in other units, by a catalytic reaction in the presence of hydrogen. At the moment of the leak the furnace was restarting. The alarms of the temperature sensors at the oven outlet were triggered. At 4:08 a.m., the operator shut down the hydrogen compressors and diesel charging pumps, closed the supply valves and called the emergency status. The first emergency operation was to decompress the unit.

This near miss occurred at an airport's hydrogen refilling station. At 7:35, a hydrogen leak was detected by hearing whistles in the near of a pipe. The operators warned the airport firefighters ten minutes later. Upon their arrival, the firefighters set up a security perimeter of 150 m around the installation. The station is located on the border between the public space and the private space and was surrounded by a fence with a gate accessible only by a code unknown to the emergency services.

This near miss occurred at metal smelting unit of a foundry. At 9:45 a.m., due to a power outage, the cooling pumps of two furnaces containing nickel and chromium stopped. One of the two furnaces was at the end of the smelting cycle. The temperature of the metal was 1300C. Due to the stop of the cooling system, water from the public network took over the cooling function, but was not efficient, causing the cooling coil to overheat.

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 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.

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.

The 10 m3 hydrogen storage tank at the hydrogen station belonging to the oxygen plant exploded during production operation. The hydrogen storage tank was installed and used by the plant in 1995, with a design pressure of 1,5 MPa, a volume of 10 m^3, a minimum wall thickness of 12 mm, a total length of 4576 mm (height) and an inner diameter of 1800 mm. After the explosion, there were no metal components left, except for the cement prefabricated foundation of the tank base.