The IMO has approved interim safety guidelines for gas carriers using ammonia cargo as fuel, marking a significant regulatory step for one of shipping’s most closely watched zero-carbon fuel pathways.
The guidance, adopted during the IMO Maritime Safety Committee’s 111th session in London, is intended to provide shipowners, designers and flag administrations with a clearer framework for managing the operational and safety risks associated with ammonia propulsion.
Developed jointly by Lloyd’s Register, Belgian transport authority FPS Mobility and gas carrier operator EXMAR, the guidelines focus on the safe handling of ammonia onboard ships, particularly given ammonia’s toxicity and distinct handling requirements.
Liam Blackmore, global head of technology adoption and integration at Lloyd’s Register, said: ‘The approval of these guidelines provides a clear signal that ammonia is moving from concept to a fuel with an emerging international safety framework. It demonstrates how close collaboration between industry, flag administrations and technical organisations can accelerate the safe adoption of new fuels at scale.’
A key element of the IMO discussions was clarification over the application of the organisation’s ‘one ship, one code’ principle for gas carriers using ammonia. The interim framework confirms that gas carriers using ammonia cargo as fuel will remain regulated under the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk, rather than the IGF Code, which applies to other ship types using low-flashpoint fuels.
The clarification is intended to avoid overlapping regulatory requirements as alternative fuel projects move from the pilot phase towards fleet deployment. DNV commented that the IMO’s position was designed ‘to avoid unintentional consequences that could arise from selecting requirements from various codes’.
The guidelines will reduce uncertainty for owners evaluating ammonia-fuelled tonnage, particularly in the gas carrier segment where ammonia cargo containment and fuel use intersect.
The IMO also approved interim training guidance for seafarers working onboard ammonia-fuelled vessels, reflecting growing concern across the industry over the human and operational risks associated with alternative fuels.
The training framework is based on existing LNG seafarer training standards, adapted for ammonia’s specific hazards. Similar guidance was also approved for ships using methanol fuel.
Celine Audenaerdt, head of environmental and technical affairs at the Royal Belgian Shipowners’ Association, said: ‘Through intensive collaboration and the combination of strong in-house competence and hands-on experience, the partners have succeeded in developing robust and practical safety guidelines.’
Kristof Coppé, director fleet operations and technical business development at EXMAR, said the guidelines drew on ‘more than four decades of operational experience and the challenges encountered along the way’.
The interim measures will be considered for formal adoption at MSC 112 in December 2026. If approved, they are expected to enter into force in July 2028 for newly constructed vessels.
