The International Maritime Organization (IMO) has developed Interim Guidelines for ships using ammonia as fuel. These guidelines aim to provide an international standard for the arrangement, installation, control, and monitoring of machinery, equipment, and systems utilizing ammonia as fuel, thereby minimizing risks to ships, their crews, and the environment. The guidelines are recommendatory in nature and apply to ships not covered by the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code).

As of December 2024, these Interim Guidelines were approved during the 109th session of the IMO's Maritime Safety Committee (MSC 109). However, the finalized guidelines have not yet been published as a standalone document. For reference, a draft version titled "INTERIM GUIDELINES FOR THE SAFETY OF SHIPS USING AMMONIA AS FUEL" is available  here.

For the most accurate and up-to-date information, it is advisable to consult the official IMO website or contact the IMO directly to obtain the finalized Interim Guidelines once they are published.