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.

A hydrogen leak took place on a trailer carrying compressed hydrogen, located inside the fenced perimeter of a hydrogen station. According to the company managing the hydrogen delivery and refuelling station, the leak did not pose any risk to people or the environment. A preliminary assessment identified a faulty valve s source of the leak, but t was unclear a that time if it was a single defect or a systemic (i.e. design) problem.

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.

The accident occurred at a production, distribution and storage station for hydrogen city busses. After filling the hydrogen cylinders of a bus, the hydrogen detection system of the bus triggered an alarm. The site technician pushed the emergency button and the station was put in safety mode. The technician in charge of filling disconnected the hydrogen hose that connects the station to the bus. The maintenance manager of the bus manufacturer was alerted and arrived 20 minutes later and evacuated the personnel. They closed the valves of the on-board storage system.

Hydrogen leak due to a fault with non-process related battery equipment.After reporting the hydrogen leak, fire crews have been called to a gas terminal. The leak was due to a fault with non-process related battery equipment.

The tanker truck was carrying nearly 13,000 gallons of liquid hydrogen. it hit the base of a light pole in the parking lot of a local grocery store as the driver was attempting to turn around. Hydrogen gas then began leaking out of it. This resulted in a valve on the truck to become damaged and could have caused the liquid hydrogen to be released from the truck, a very serious situation for nearby residents and businesses. Nobody was physically harmed by the incident.

The truck overturned and lost vacuum insulation. The hydrogen boiled and vented, but there was no ignition. The potential for fire or explosion, however, led to precautions that did cause considerable disruption: the interstate highway where the accident occurred was closed and nearby homes and businesses were evacuated.

the commercial vehicle was traveling when the two-person crew noticed what appeared to be smoke emitting from the tanker trailer. The crew called 911 and safely pulled to the side of the road Fire brigade, law enforcement and Department of Transportation personnel then escorted the vehicle to a safe location near a University main campus. The hazard response team entered in contact with the transportation company and left the tanker depressurizing and off-gassing till it was safe for it to further travel.

The hydrogen leak occurred on a lorry travelling on a motorway. According to Highways England the vehicle was carrying nine cylinders of gas, one of which had a crack and was leaking. The only way to allow it to safely disperse was to let it vent.An exclusion zone was set up around it and the road closed. The incident led to delays of up to 90 minutes during rush hour.