The event occurred at the flanges on the outlet of a desulfurization reactor, which was working under about 300 degrees C The flanges and bolts were cooled down by a large amount of rainwater which had got into the rain-cover around the flanges. This caused the material to shrink and made the flanges too tight, putting too much stress on the ring gaskets which deformed and damaged. As a result, hydrogen gas and light oil mist leaked out and ignited spontaneously, causing damage to pressure gauges and insulation of pipes.

The event occurred at an ethylene production plant. The plant was shutdown at the time as the supply of compressed air to the gauges had inadvertently been switched off. This failure of the air supply was not immediately recognised because of the low pressure alarm was installed before the isolation valve. Shortly after the plant was restarted an unusually high temperature was observed in an acetylene hydrogenation column.

This incident occurred unit at a demonstration of a new technology for the catalytic cracking of vacuum residual oil. An oil storage tank failed due to high pressure. The overpressure in the tank was the result of a backflow of compressed hydrogen gas. When operators reduced the discharge pressure of the feedstock feed pump, high-pressure hydrogen gas in the reaction system flowed back into a feedstock surge drum and then into the cooling oil receiver. The pressure of the cooling oil receiver increased and the oil blew out and the feedstock surge drum ruptured and a fire occurred.

This incident occurred at a linear alkylbenzene manufacturing plant. It affected dehydrogenation reactor of normal paraffin, during the operation of catalyst exchange in the reactor. This is usually happening by isolating the reactor and its peripheral part from the slightly pressurised section by closing a 20-inch remotely controlled valve. The hydrogen pressure of the peripheral part was set at 20 KPa, and the reactor was opened to the atmosphere. Assuming the possibility of small hydrogen leakage, a vacuum device was used to evacuate the piping and a nitrogen purging was performed.

At a refinery, a leakage and fire occurred during usual operation at a medium-pressure hydrocracker for the desulfurization and decomposition of heavy gas oil. Gas of high-temperature and high-pressure leaked through a flange with a special shape located at the reactor outlet, and a fire occurred. The fire occurred on changing operating conditions of a medium-pressure hydrocracker for gas oil at a refinery. Process fluid leaked from the flange with a spacer at the reactor outlet after the operation temperature of the reactor was lowered, and a fire occurred.

An explosion occurred at testing facility of a space rocket engine. The incident occurred when executing a test studying the performance of a hydrogen gas flow measuring system for fuel feeding system of the rocket. During testing of a 42 MPa high-pressure hydrogen gas flow system, an exhaust gas duct outlet was damaged; hydrogen blew out and exploded. Apparently the cause of this accident was the deterioration of the exhaust gas duct outlet by thermal stress.A test started, The hydrogen gas begun flowing.

The explosion occurred at the hydrogen producing unit of a refinery.A solution of potassium carbonate was being drawn off from an absorption tower to a temporary storage tank for a turnaround shutdown maintenance. The tank exploded, due to backflow of hydrogen into the tank. The level of the solution in the tower was not checked. When a water solution in an absorption tower for carbonic acid gas is drawn off, the water level of the solution drops. This drop \was ignored and the pump cavitated.

The incident affected at an indirect oil desulfurization unit, and originated at a piping at the outlet of a heat exchanger. The exchanger was located in the furthermost downstream of the reactor. The dead-end cap of the piping failed due to corrosion and opened, releasing high-pressure hydrogen which leaked, ignited and exploded. Due to the explosion, the heat exchanger was damages and oil leaked out contributing to spread the damage. Approximately 1200 kg of hydrogen and 30000 l of oil were burned. No injuries.

The explosion occurred in an incinerator for non-industrial wastes, during inspection and repair works. These were due to a large quantity of aluminum which produced a solid lump of ash. The explosion occurred during clean-up operation of this lump piled in a hopper chute at the lower part of the incinerator. In an attempt to favor the cleaning process, large quantities of were injected, which reacted with the aluminum to form flammable atmosphere consisting mainly of hydrogen. The hydrogen entered then in contact with air when the inspection door was opened, ignited and exploded.