The IMO’s Sub-Committee on Pollution Prevention and Response (PPR) agreed a series of draft technical amendments at its 13th session in London in February, work that will shape how alternative fuels and emissions controls are certified under MARPOL.
A central outcome was agreement on proposed amendments to MARPOL Annex VI and the 2008 NOx Technical Code to enable the certification of engines operating on non-carbon-containing fuels or fuel mixtures. Existing test methods rely on measuring carbon in exhaust gases, which is not applicable to fuels such as hydrogen and ammonia.
DNV said the revisions include ‘the introduction of hydrogen and oxygen balance methodologies to complement the existing carbon balance approach’. The amendments are expected to be approved at the Marine Environment Protection Committee’s 84th session (MEPC 84) in April 2026, with adoption targeted for MEPC 85 in November 2026.
The sub-committee also continued technical discussions on measures to reduce black carbon emissions in the Arctic, including the development of a potential polar fuels concept. Member States and international organisations were invited to submit updated proposals to PPR 14 in 2027, with attention to consistency with existing MARPOL provisions on fuel oil quality.
Exhaust gas cleaning systems remained under review. PPR 13 considered proposals to restrict scrubber discharge water in Particularly Sensitive Sea Areas. DNV reported that the sub-committee concluded proposing Member States should first undertake a risk assessment, and then determine whether discharge restrictions are reasonable based on the findings.
In addition to air emissions, PPR 13 agreed a draft 2026 Strategy and Action Plan to Address Marine Plastic Litter from Ships, for adoption at MEPC 8427 April – 1 May 2026). The updated framework reaffirms IMO’s objective of achieving zero plastic waste discharges to sea from ships by 2030 and includes measures on awareness, training and port reception facilities.
The sub-committee recommended that MEPC consider developing a new mandatory code on the maritime transport of plastic pellets in freight containers, potentially under MARPOL Annex III and or SOLAS. It also approved a draft circular promoting the implementation of fishing gear marking systems, aligned with FAO voluntary guidelines.
Further work progressed on amendments to MARPOL Annex VI to require new crude oil tankers to install pressure-vacuum devices to control volatile organic compound releases. Discussions also continued on revisions to MARPOL Annex IV on sewage management, including the introduction of sewage record books and sewage management plans.
The February session forms part of IMO’s ongoing technical programme ahead of decisions at MEPC 84 and MEPC 85, with several draft instruments expected to advance through the approval and adoption process during 2026.
