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 fire developed on a hydrogen bus during filling, and was detected due to the development of smoke and a smell of burned materials.The power cable of the compressor had overheated. Two are the possible causes: (1) the cable had been wrongly installed or fixed, or (2) the electrical system had caused too high current in the cable. The corrective actions have been:(a) To ship the affected component to the manufacturing company for inspection(b) To replacement of the affected component with a new one. (c) To perform an inspection of the system on all the other buses in function.

The accidental hydrogen release occurred when testing the storage system connected to a PEM electrolyzer. The leak test consisted in filling the storage with hydrogen at step-wise increase of pressure. After the step at 3 bar (0.3 MPa), which did not reveal any leak, the storage was pressurised up to 5 bar (0.5 MPa). At that moment a hissing sound occurred from the storage at the outside of the building indicating a leak.

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.

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.

Early in the morning of (3:00 AM), the personnel on one of the companies on site reported a potential pipeline leak just south of the valve station. The potential leak was discovered due to bubbling water in the ditch. No visible hydrocarbon sheen was noted, indicating a probable non-hydrocarbon gas leak. Later in the morning, the personnel tested their area gas pipelines and determined that their company was not the source of the leak. Later on the same day, another company tested their pipelines and determined that their hydrogen pipeline was the source of the leak.

At 17:30 on 5 may 2019, the pipeline operator was notified by a third party that there was a possible leak on its hydrogen pipeline, as identified by sound. Operator personnel arrived on the site at 18:30 and confirmed that hydrogen was present in the area. The location was in an isolated area. Manual isolation valves were shut to close in the segment and it was manually blown down. At 08:52 on of the day after the operator determined that the incident met reportable criteria and called the national response centre at 09:22.

Release from a welding of a hydrogen transmission pipeline At 12:45 pm the operation control centre (OCC) recognised that a customer flow and pressure dropped significantly. At 13:28 the OCC made the decision to close the upstream remote operated valve. At 15:00 the pipeline technician arrived on site and confirmed the breach in the pipeline. Additional pipeline operations technicians were deployed to isolate both manual block valve upstream and downstream of the incident site.