DNV has completed a multi-year study for the European Maritime Safety Agency (EMSA), concluding that hydrogen-fuelled ships require a design-based safety approach, including secondary enclosures around all hydrogen-carrying components, even those located on open deck.

The study, titled 'Safety of hydrogen for use in ships,' resulted in a final report and a non-mandatory guidance document published on 12 March.

According to the report, hydrogen presents different safety risks compared with other alternative marine fuels such as LNG. Even small leaks can quickly form ignitable gas clouds, and when combined with hydrogen’s low ignition energy and the difficulty of detecting leaks, this heightens the risk of explosion.

DNV said these characteristics require additional onboard technical barriers to manage leakage and reduce risks associated with hydrogen fuel systems.

Cristina Saenz de Santa Maria, Interim CEO Maritime, DNV, commented: “Hydrogen has a viable path as ship fuel but carries safety risks. As new fuel technologies develop, robust safety principles must be built in from the outset. That requires new thinking, early-stage integration, and close collaboration across the value chain, while keeping seafarer safety firmly at the centre.”

The study also highlights operational implications for crews. Because hydrogen is highly flammable and must be stored at very low temperatures in its liquefied form, it introduces new occupational hazards for seafarers.

DNV said crews will need specialised training to recognise hydrogen-related risks and understand how to mitigate them. This should be supported by clear operational procedures and safety management systems, with human behaviour and organisational safety culture providing an additional layer of risk control.

Linda Hammer, Principal Consultant, DNV and lead author of the study, stated: “The study concludes that safety for hydrogen-fuelled ships must be based on technical safety barriers, with robust containment, secondary enclosures, and automated protection systems forming the first line of defence. This reflects both the speed at which hydrogen incidents can escalate and the limitations of detection and response once a release has occurred, particularly in complex maritime environments.”

Hammer added: “We have valued the opportunity to deliver this study for EMSA, and the support from industry partners throughout the process, and welcome the continued collaboration with both regulators and industry as the work moves forward.”

The full EMSA study examining hydrogen safety in maritime fuel applications is available here.