IMO Approves Interim Ammonia Fuel Safety Guidelines as Exmar Pioneers First Dual-Fuel Gas Carriers

The International Maritime Organization has approved interim safety guidelines for the use of ammonia as fuel on gas carriers, providing a practical framework to manage the specific risks associated with ammonia's toxicity and handling requirements. The guidelines, approved at the 111th session of IMO's Maritime Safety Committee in May, were developed through collaboration between Lloyd's Register, the Belgian Federal Public Service Mobility and Transport, and Antwerp-based ship operator Exmar, which named the world's first ammonia dual-fuel mid-size gas carriers, Antwerpen and Arlon, at HD Hyundai in South Korea in April.

 

Strategic Significance of the Regulatory Development

 

The approval of interim ammonia fuel safety guidelines represents a meaningful step in the transition of ammonia from a conceptual alternative fuel to one with an emerging international regulatory framework. Ammonia has been identified as one of the most credible zero-carbon fuel pathways for shipping because it contains no carbon and can be produced from renewable energy, but its toxicity and the complexity of its handling requirements have created significant safety and regulatory barriers to commercial deployment. The new guidelines directly address these barriers by establishing a practical framework that covers safe on-board handling, management of toxic risks, and the safety system requirements specific to ammonia as a marine fuel. Their approval signals that the international regulatory community is prepared to support ammonia-fuelled shipping as a commercially viable technology.

 

Exmar's Role as Industry Pioneer

 

Exmar's Antwerpen and Arlon, named at HD Hyundai in South Korea in April 2026, are the world's first ammonia dual-fuel mid-size gas carriers, making the Belgian operator the commercial pioneer in the segment. The two 46,000 cubic metre vessels were developed through close collaboration between Exmar, HD Hyundai, Lloyd's Register, HHI-EMD, Wärtsilä Gas Solutions, and WinGD, with the propulsion system combining two-stroke ammonia dual-fuel engines, fuel gas supply technology, and safety systems developed specifically for the vessels. The ships will fly the Belgian flag, reinforcing Belgium's role in the governance and regulatory development underpinning the programme. Exmar director of fleet operations and technical business development Kristof Coppé has framed the guidelines as the product of a strong partnership built on more than four decades of operational experience in gas carrier operations and the lessons learned in working through the technical challenges of ammonia fuel integration.

 

Regulatory Process and Industry Collaboration

 

The interim guidelines were developed with the Directorate-General Shipping of the Belgian Federal Public Service Mobility taking the lead at IMO in drafting the safety text, drawing directly on the real-world experience of Exmar and Lloyd's Register in mid-size gas carrier shipbuilding and ammonia fuel system development. The approach of grounding international safety guidelines in operational and engineering experience from actual vessel construction is commercially significant because it produces rules that reflect the practical realities of ammonia fuel handling rather than purely theoretical risk assessments. FPS Mobility maritime expert in alternative fuels Nathalie Deleuze has framed the agency's role as ensuring that an appropriate regulatory framework is in place in good time to facilitate the energy transition, reflecting a proactive approach to maritime alternative fuel governance that other flag administrations may seek to replicate.

 

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Ammonia's Safety Challenges and How the Guidelines Address Them

 

Ammonia presents a distinct safety profile compared with LNG or methanol as a marine fuel, primarily because of its acute toxicity to humans and marine life, its corrosive properties, and the specific emergency response requirements associated with its release. The interim guidelines provide a framework for managing these risks through requirements covering on-board detection systems, personal protective equipment, emergency procedures, crew training, and the physical design of fuel containment and supply systems. The guidelines also address the interface between ammonia-specific safety requirements and the existing framework of codes governing gas carrier construction and operation, providing guidance on how the two regulatory streams should be reconciled for vessels like Antwerpen and Arlon that carry both cargo ammonia and ammonia used as propulsion fuel.

 

Lloyd's Register's Assessment of the Milestone

 

Lloyd's Register global head of technology adoption and integration Liam Blackmore has described the approval as a clear signal that ammonia is moving from concept to a fuel with an emerging international safety framework, and has highlighted the collaboration between industry, flag administrations, and technical organisations as the mechanism that has accelerated the safe adoption process. The involvement of a major class society as a co-developer of the guidelines, rather than purely as a certification body, reflects the increasingly central role that classification societies are playing in translating novel fuel technologies into internationally recognised safety standards. LR's direct participation in the Exmar vessel programme provides the empirical foundation for the guidelines' practical credibility.

 

Implications for the Ammonia-Fuelled Shipping Pipeline

 

The approval of interim guidelines comes at a critical moment for the ammonia-fuelled shipping market. Several shipowners have ordered or are considering ordering ammonia dual-fuel vessels, and the absence of a clear international safety framework has been cited as a barrier to final investment decisions and commercial deployment timelines. With the interim guidelines now in place, owners, shipbuilders, equipment suppliers, and port operators have a regulatory reference point that supports project planning, system specification, and crew training development. The interim designation reflects the expectation that the guidelines will be refined and potentially updated as operational experience from Antwerpen, Arlon, and other early ammonia-fuelled vessels accumulates and is incorporated into the regulatory framework.

 

Outlook for Ammonia as a Marine Fuel

 

The combined momentum of the Exmar vessel programme and the IMO guideline approval suggests that ammonia-fuelled shipping is advancing more rapidly than some analysts had anticipated toward commercial deployment. The technology challenges that remain, including the refinement of ammonia combustion in two-stroke engines, the development of bunkering infrastructure, and the scaling of green ammonia production, are substantial but are being actively addressed by a broad ecosystem of shipbuilders, engine manufacturers, fuel system suppliers, and energy companies. As the first ammonia dual-fuel gas carriers enter service, the operational data they generate will be critical to refining safety guidelines, informing bunkering standards, and building the case for broader adoption of ammonia as a zero-carbon marine fuel.