Figure 1
Primary failure frequency by cause and size of leak for natural gas transmission pipelines in the EGIG database, years 2013–2022, based on 171 incidents (EGIG, 2023).
Table 1
Relevant incidents involving hydrogen pipelines extracted from HIAD 2.2, version released on 1 January 2026 (JRC, 2026).
| HIAD EVENT ID DATE COUNTRY ORIGINAL SOURCE | SHORT EVENT DESCRIPTION |
|---|---|
| #154 2006-10-20 UNITED STATES PHMSA (PHMSA, 2026) | A release of hydrogen during the installation process of a new pipeline. Due to human error, hydrogen was released and ignited, injuring one operator. |
| #191 2002-12-03 UNITED STATES PHMSA (PHMSA, 2026) | Circumferential rupture of a hydrogen pipeline at a place where a previous leak had been repaired. A plausible cause of the failure was the heat applied during the weld repair. |
| #478 2019-05-06 BELGIUM News – Sud Info (Sud Info, 2019) | An abnormal noise was reported from a hydrogen pipeline. The pipeline was depressurised, emptied and repaired. No impact was reported. |
| #759 2007-10-12 NETHERLANDS VROM (VROM, 2009) | A leak occurred at an underground steel pipeline of six inches in diameter transporting pressurised hydrogen at 75 bar. The leakage occurred at a so-called ‘CP coupling’. The released hydrogen was ignited by nearby welding activities, resulting in a small fire. It is unclear how long the leak persisted before the ignition. |
| #891 2019-03-21 BELGIUM ARIA (ARIA, 2026) | Excavation work was performed nearby a buried pipeline of gaseous hydrogen. The excavation machine hit the pipeline, causing a jet fire. No injured person was reported. The excavation machine was burnt during the accident. |
| #933 2013-04-18 FRANCE ARIA (ARIA, 2026) | A worker detected a small leak from a pipeline for hydrogen transport (OD = 80 mm, p = 75 bar). The pipeline was emptied and repaired successfully. |
| #1027 2021-03-21 BELGIUM ARIA (ARIA, 2026) | 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 the emergency procedures in place to ensure the safety of the local residents and of the pipeline. |
| #1056 2021-02-15 UNITED STATES PHMSA (PHMSA, 2026) | A hydrogen release and subsequent fire occurred at a meter station on a pipeline transporting hydrogen to a refinery. For various reasons, the hydrogen pipeline was operated at a larger than normal flow rate. The incident investigation identified that there was erosion of the flow tubes in the gas meter. The initial event led to subsequent failures of the skid, including the gas meter housing, meter flange, an eight-inch manufactured elbow, and an eight-inch bypass line. |
| #1057 2022-02-05 UNITED STATES PHMSA (PHMSA, 2026) | A release from a hydrogen transmission pipeline occurred following welding on the pipeline. The pipeline was isolated. |
| #1058 2019-05-05 UNITED STATES PHMSA (PHMSA, 2026) | A third party heard a leak in a hydrogen pipeline. The pipeline was isolated, stopping the leak. The source of the leak could not be identified due to some parts being inaccessible. Parts of the pipeline were replaced by a new segment with a new route, and the pipeline was later put back into service. |
| #1059 2018-11-12 UNITED STATES PHMSA (PHMSA, 2026) | A potential hydrogen pipeline leak was observed due to bubbling water. The pipeline was depressurised, stopping the leak. Due to its small size, the leak was not identified by the automated control system. |
| #1060 2015-04-28 UNITED STATES PHMSA (PHMSA, 2026) | An in-line inspection of the hydrogen pipeline was being conducted, and prior to the last run of the in-line inspection tool (magnetic flux leakage), 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 injured personnel. |
Figure 2
Countries where the incidents occurred, including consequence, cause, and place of incident for the 12 identified incidents involving hydrogen pipelines from the HIAD 2.2 database (incidents may have more than one cause).