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 company affected manufactures valves and other hydrogen-storage components, equipment tests. It has offers as well a testing laboratory. The accident happened during testing of a hydrogen tank. A dull bang and a huge pressure wave was felt kilometres away. News report massive damage to the test facility, but a very small fire. Still according to the news, the most probable cause emerging from the investigation is the over-pressuring of the tank due to an erroneous connection of a compressed air hose.

[NOTE: One source speak of a hydrogen gasometer, spanish news speak in general of gas, others of ntural gas or coal gas; considering the main product of the factory, it was chosen for this last version, but is is rather doubtful]This incident occurred at a coal gas storage (gasometer) system of a producer of foundry coke. The gasholder was a variable capacity tank, rising in height depending on the amount of gas stored, with a maximum capacity of 24,000 m3.Company sources said that the fire was caused as a result of a spark and a gas leak that was being repaired by the operators.

A 9000 gal (34 m3) LH2 storage tank exploded during repair of the vent stack. Few days before the explosion, the tank had been filled with LH2, but later on the hydrogen released and ignited at the tank pressure control system, damaging the vent stack. To perform the required repairs, the tank had to be emptied. To this purpose the vessel was purged with nitrogen gas to display the LH2 by letting it boiling. However, the pressure inside the vacuum jacket increased because of the opening the vacuum valve. This pressure increase eventually led to the catastrophic tank rupture.

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.

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.

A cryogenic hydrogen laboratory had a power outage. The cryogenic hydrogen storage was no longer being cooled, therefore temperatures and pressures within the storage system started rising. There were several relief devices on the system, one with a set point of 150 psi (approximately 1 MPa) and a second at a set point of 165 psi (1.1 MPa). The system was monitored by site personnel so that when the hydrogen pressure increased to 120 psi (approximately 0.5 MPa), a manual vent was opened. However, the manual vent rate was not able to control the rising pressure.

A hydrogen safety sensor went into alarm at a hydrogen demonstration facility. The early morning temperature was near freezing and there was a trace of precipitation on exposed surfaces. Upon further inspection following the sensor alarm, a 3,500 psig (approximately 24 MPa) stationary storage vent was found to be releasing hydrogen through the PRD vent stack (PRD = Pressure Relief Device). The alarming sensor was at an adjacent building but responded to hydrogen 20 yards (18 m) downwind from the vent location. The vent release location is 10 feet (3 m) above ground level.

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.

The safety cabinet with compressed hydrogen was located in a laboratory and used to supply hydrogen to an experimental facility. The safety cabinet was equipped with exhaust extraction. Due to a leak, technical assistance had been requested from the fire department. The head of laboratory shut off the electrical supply to the laboratory. Measurements showed that there was no potentially explosive atmosphere in the laboratory room.