The incident involves a gas booster provided by a manufacturer. This device is used in the experimental platform of the project to raise the pressure in pipelines from 60 to 80 barg (from 6 to 8 MPa), allowing the gas to flow in a close loop. After 5 weeks of operation, a critical gas leakage through the vent port was detected.At the moment of the incident, the compressor was working with a mixture of hydrogen and methane (H2/CH4 blend 20/80 %v/%v). The booster was sent to the manufacturer for inspection and reparation. Severe damage in the seals of the vent port was found.

An in-line inspection of the hydrogen pipeline was being conducted and prior to the last run of the in-line inspection tool (mfl), hydrogen gas was released and ignited from a blind flange connection failure on a temporary separator filter installed at the receiver site. The fire was immediately identified by on-site personnel. There were no injuries. The pipeline section was isolated and de-pressurised to the facility flare. Local emergency responders were dispatched and contained and extinguished the fire. The fire affected the station piping and equipment in the surrounding area.

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.

A hydrogen release and subsequent fire occurred at meter station of a pipeline transporting hydrogen to a refinery. Local refinery emergency response team responded and secured the area. The pipeline was isolated, and the fire extinguished itself. During a winter storm, the area was experiencing abnormal freezing conditions and widespread power outages were occurring. As a result, third party hydrogen supply to the refinery was reduced. These upsets resulted in the need to export larger than normal flow rates on the hydrogen pipeline.

During agricultural drainage work carried out by a farmer, an explosion occurred on a hydrogen pipeline located in a field. Flames several meters high were visible and two houses were evacuated. A safety perimeter was set up. The pipeline operator applied procedures to ensure the safety of the local residents and the pipeline.The damaged pipe was listed by the operator. The farmer did not declare the work site and no verification was done before starting the work.[ARIA event 57406]

During maintenance work on a gas pipeline carrying hydrogen , a worker hears a leak at about at a bridge. The operator measures an concentration of 3% of the low flammability limit at few centimetres from the leak, and no detection beyond 25 cm. The area was highly ventilated. The technicians secured the area, isolated the section five hours later and started the controlled gas release. after two additional hours the pressure had reduced to zero and they started the nitrogen inerting. The pipe was repaired the next day.

Excavation work was performed nearby a buried pipeline of gaseous hydrogen. The excavation machine hit the pipeline causing an under-expanded jet fire. No injuries. The excavation machine was burnt during the accident.Additional investigations are in progress to understand why the third party company was not informed or has not transfer the information to the workers of the presence of the hydrogen pipeline.

Fire broke out along a transition corridor combining several underground pipelines transporting hazardous substances, including hydrogen, kerosene and ethylene oxide. The fire was brought under control within a few minutes thanks to the limited size of the leak.