Despite all the safety measures to ensure the operation of hydrogen filling stations, a hydrogen filling station explosion occurred on 10 June 2019 in the Norwegian municipality of Bærum. Two people who were in a vehicle near the hydrogen filling station were injured in the accident. The explosion was so powerful that it triggered the airbags of vehicles in the vicinity. The manufacturer of the hydrogen filling station was NEL, it is the largest manufacturer of electrolyzers with a history dating back to 1927 and a leading manufacturer of hydrogen filling stations.

The owner of the affected hydrogen filling station is Uno-X Hydrogen, the station was opened in 2016. It was a Nel H2Station with on-site hydrogen production.

The main cause of the explosion was a poor tightening of the bolts on the hydrogen storage tank, which led to a gradual failure of the sealing system, followed by an uncontrolled leakage of hydrogen (time: 17.30) and then an explosion (time: 17.37). Subsequent investigation revealed an error in the assembly of the high pressure storage unit, which consists of steel tanks and other components from subcontractors.

The investigation tested the high pressure storage tanks used in this type of filling station and found the system to be completely safe in terms of material structure and design, but the assembly of the system was found to be unsafe. Inadequate tightening of the bolts can cause a hydrogen leak with fatal consequences.

Following this incident, NEL has tightened the control of the assembly of the pressure vessels even further, with the individual assembly steps being controlled as in the aerospace industry.