Two workers were asked to change the piping and support of a feed line into an intermediate storage vessel for hydrochloric acid. The explosion occurred when they opened the gas line and started grinding on the support, The flame propagated back into the tank, causing a second explosion inside. The explosion was caused by the unexpected presence of a considerable amount of hydrogen in the tank. According tot the eMARS and ARIA report (see references) , the hydrogen was formed in a reaction of metal powder traces and the hydrochloric acid, and must have accumulated over a period of two months.

A fire in a metallurgical plant (classified Seveso)The fire initiated in a acid treatment reactor of a workshop handling cementation of indium . Under normal conditions, the reaction of the process in the tank releases hydrogen. The fire propagated to the plastic components above the tank, causing black smoke released inside the workshop. The origin of the fire were sparks produced by the grinding of metal gratings overhanging the tank.

The fire broke out on a worm ("vis sans fin") supplying a conveyor of aluminum. The ignition of the powder on the ground was caused by the flame cutting operation on the worm shell which generated scales. The incandescent Al dust has been then swept by the wind spread to the atomisation tunnels, the sewers and a lost well. The dust and hydrogen formed upon contact with water caused four violent explosions. The fire spread to a stock of Al powder stored in bags and drums.

The explosion occurred in a copper electroplating plant test furnace when starting the operation of copper plating. EVENT DETAILS A tinned copper pipe had been placed inside another copper pipe and lined with pellets. Inside the furnace, the pellets were intended to adhere to the outer surface of the smaller tinned copper pipe under hydrogen atmosphere. The test was the third in the series. A vacuum was created inside the furnace, and an indicator light showed that a vacuum had been successfully generated.

Five barrels of aluminum dust that had been removed from an outdoor dust collector were sealed and stored in the plant adjacent to electrical panels. One of them had somehow been contaminated with water, which exothermically reacted with the aluminum dust to form hydrogen gas. The top of the barrel deformed and glowed red. Smoke was observed and an employee sounded a vocal alarm. The lid blew off the barrel and the mushroom cloud of aluminum dust exploded in a fireball. Nearby combustible material ignited and the sprinkler system activated.

Fire following vapour explosion at a plant making titanium sponge due to design errors: A vapour explosion, followed by a fire, occurred at a drier in a plant making titanium sponge. When titanium containing water was put into the drier, it came to contact with the edge of the protecting tube of the inside thermometer, generating sparks which ignited the titanium sponge. The red-hot titanium sponge melted the drier to leak out, and reacted with water spilled from the fractured drier, producing hydrogen gas.

Fire of drums containing lithium metal powder: Spontaneous combustion took place at drums containing lithium metal powder which were charged with argon gas for experiments. While lithium metal powder had usually been kept inside films of fluid paraffin to avoid its contact with water, it was stored in drums charged with argon gas for reuse in a tentative way. Water in the air got in to react with lithium because of incomplete sealing of the drums. In addition, the reaction heat built up under hot and humid condition on the day of accident leading to ignition of hydrogen or lithium.

The release of a blast furnace gas occurred at a section of pipework, due to the rupture of valve seal. The gas did not ignite and the fire service attended as a precaution. The gas was both flammable and toxic, containing 21% carbon monoxide and 5% hydrogen.The onsite emergency plan was activated and the workers sheltered in toxic gas refuges. A concentration of 400 ppm carbon monoxide was measured 200 metres away at the power station, but there were no off-site effects.

At a soaking facility of an industrial plant in the metallurgy sector, the pipeline between a supply tank and a feed pump became clogged and the autoclave only received sporadic feed. Problems had been experienced with the feed over several days. The pipeline was flushed with water to little avail. Because no feed was received in the autoclave, no oxygen could enter to maintain the pressure of the autoclave normally. The blockage was quickly cleared, as a result of which a large quantity of feed, and with it solids that were contained in the blockage, entered the autoclave.

The reduction stage of the powder production process of a chemical plant had been shut down, and the buffer tank of the line had been drained on the preceding day. After the shutdown, the batch to be reduced was normally processed in the autoclave and the process was duly acknowledged. The sequence opened the autoclave degassing operation via the cyclone up to the roof, as a result of which the pressure inside the autoclave started to fall. Soon after that, an explosion occurred in the buffer tank downstream of the autoclave and at the gas scrubber.