INTRODUCTION
MARPOL Annex VI mandates a global ship fuel sulphur cap of 0.5% together with Emission Control Area (ECA) caps of 0.1% in five designated ECAs. Additionally, Regional/Domestic ECAs (DECAs) with 0.1% caps exist under coastal state laws which are independent from MARPOL. This Risk Bulletin focuses on the growing expansion of MARPOL ECAs and Regional DECAs, their 0.1% sulphur cap requirement and the critical need to ensure awareness and full compliance.
BACKGROUND AND CURRENT STATUS – MARPOL ANNEX VI ECAS
MARPOL Annex VI defines ECAs as: “…areas where the adoption of special mandatory measures to regulate emissions from ships is required to prevent, reduce and control air pollution from NOx and/or SOx and/or particulate matter (PM) and their adverse impacts on human health and the environment”.
The purpose of MARPOL Annex VI is to regulate air pollution from ships, focusing primarily on the emission reduction of sulphur oxides (SOx), nitrogen oxides (NOx), and particulate matter (PM). As noted above, ECAs are designated sea areas where stricter emission standards (inclusive of a 0.1% sulphur emission limit) are enforced to minimise air pollution near coastal regions.
Ships operating within ECAs must meet the specified standard by using fuel with an ultra-low 0.1% sulphur content or, alternatively, by using exhaust scrubber systems capable of reducing fuel exhaust emissions to the same level as 0.1% sulphur content fuel. Further, and as may be specified by designated ECA requirements, by employing approved technologies to reduce NOx and PM emissions.
NOTE: Scrubber systems (both open and closed loop) can reduce exhaust emissions to the both the MARPOL global 0.5% and ECA 0.1% sulphur cap required. However, many ports have banned the use of open loop scrubbers in port waters. In such ports, vessels with open loop scrubbers (i.e. those which cannot be set to closed loop operation) will be obligated to carry and use 0.1% sulphur content fuel only.
As detailed by MEPC.1/Circ.778/Rev.4, List of Special Areas, Emission Control Areas, and Particularly Sensitive Sea Areas, the current MARPOL regulated ECA areas and the restricted emission substances within those areas are listed below:
- Baltic Sea (SOx and NOx since Jan 2021)
- North Sea (SOx and NOx since Jan 2021)
- North America (SOx, NOx, and PM since Jan 2016)
- US Caribbean Sea (SOx, NOx, and PM since Jan 2016)
- Mediterranean Sea (SOx and PM since May 2025)
NOTE: The precise coordinates of the listed ECAs are available on the IMO’s ECAs Designated by MARPOL webpage. A map depicting these ECAs is provided on the Maritime Optima Webpage.
As for the future, additional MARPOL ECA’s have already been approved for a Norwegian Sea ECA, a Canadian Arctic ECA and a North-East Atlantic ECA which will come into force in Oct 2027. It seems likely there will be more.
BACKGROUND AND CURRENT STATUS – REGIONAL/DOMESTIC ECAS
In addition to the MARPOL ECAs, numerous Regional/Domestic ECAs (DECAs) have been put in place by coastal states keen to protect their coastal and port communities from ship exhaust emissions but without a lengthy IMO assessment and approval process. Other coastal states which, although already parties to a MARPOL ECA scheme, have considered it appropriate to supplement these schemes with their own more stringent legislation.
The risk which may then arise for Maritime Mutual Members is that MARPOL ECA expansion and complexity together with a lack of awareness of independent DECA regulation can result in misunderstandings followed by vessel detention, loss of charter revenue and significant fines.
A list of the coastal states and places to which Members’ ships may trade and in which DECAs currently exist is as follows:
- European Union (EU) – which, subject to the EU Sulphur Directive, sets a 0.1% sulphur cap applicable to all EU members and vessels in their ports.
- Turkiye – which is subject to the Mediterranean ECA and its 0.1% sulphur cap except in the Turkish Straits area (see further details below).
- Israel – which, has enacted MARPOL Annex VI into Israel law along with a mandated 0.1% sulphur cap when berthed or anchored in an Israel port area.
- Iceland – which, as advised by Iceland’s Ministry of Environment, has amended Iceland’s enactment into law of MARPOL Annex VI by mandating a 0.1% sulphur cap inside its territorial waters.
- Norway – which is now subject to an extension of the North Sea ECA and its own Environmental Safety for Ships legislation which imposes a 0.1% sulphur cap at all ports.
- China – which has established its own independent DECAs with – in some areas – a 0.1% sulphur cap (see further details below).
- South Korea – which has established its five major ports as DECAs (see further details below).
Further Details of DECAs of Potential Special Interest to Members
TURKIYE
The Turkish coastline and its territorial waters all lie within the new Mediterranean ECA, with the notable exception of the Çanakkale Strait, the Bosphorus, and the Sea of Marmara. As such, all vessels within and transiting what is commonly known as the Turkish Strait are – technically and legally – not regulated by the Mediterranean ECA and its 0.1% sulphur cap.
Instead, all transiting vessels are governed by Turkish domestic regulation which – although Turkiye is not an EU member – is aligned with EU regulation. The result is that all ships are required to use fuels with a sulphur content not exceeding 0.1% while in Turkish waters. However, there is a Turkish regulatory dispensation which reportedly permits transiting vessel to use fuels up to a maximum of 0.5% sulphur content while drifting or while anchored for not more than two hours while awaiting Turkish Strait transit.
NOTE: The information above is based on a Circular dated 22 April 2025 posted by Turkish lawyers Vitsan. This Circular includes Vitsan’s advice that the operation of open loop scrubbers in Turkish waters is prohibited. Vitsan also advise on the current high level of fines which may be incurred for any breach of Turkish regulations relating to the use of prohibited fuel or discharges from open loop scrubbers.
OBSERVATION: In the above circumstances, it is suggested to Members that to avoid any possible misunderstanding or infraction of Turkish regulations it would best to ensure that any of their vessels transiting the Turkish Straits area or other Turkish waters are always using fuel of not more than 0.1% sulphur content. Further, that if the alternative and evidently acceptable use of scrubbers is relied on then, this is only done using a closed loop scrubber system.
CHINA
China established its own Domestic ECA (DECA) system in 2015. At that time, it set a 0.5% sulphur cap for all vessels operating in China’s territorial waters.
Subsequently, upon entry into force of the IMO’s 2020 global sulphur cap of 0.5%, China’s MSA announced confirmation of the application of the IMO’s 0.5% sulphur cap in China’s territorial waters.
The same announcement included an evidently phased in DECA application:
- As from 1 Jan 2020 a 0.1% sulphur cap in the ‘Sea Area in Hainan Waters’.
- As from 1 Jan 2022 a 0.1% sulphur cap in the ‘Inland River Control Area’ (noted as being ‘the navigable waters of the main stream of the Yangtze River and the main stream of the Xi Jiang River).
- An assessment to be completed by 1 Jan 2025 of the possible application of a 0.1% sulphur cap in all other ‘Coastal ECAs’.
NOTE: The information above has been extracted from a Huatai Insurance Agency Circular published on 14 November 2019 inclusive of a ‘Free Translation’ of P.R. China MSA Notice HFW [2018] No. 555. With reference to the possible expansion of the 0.1% sulphur cap area after 1 Jan 2025. Huatai’s recent webpage update advises as follows:
- The information published by the China MSA in 2018 remains in effect.
- The assessment referred to in relation to the possible expansion of the 0.1% sulphur cap is still underway and a final decision has not yet been made.
- At this point in time, the previously designated 0.5% sulphur cap continues except in the 0.1% sulphur cap areas previously designated.
- Huatai will provide an update if any changes are made,
OBSERVATION: For Members whose vessels are fitted with scrubbers, it should be noted that although scrubber use appears to be accepted by China’s MSA as an alternative to the use of 0.5% or 0.1% fuel (as appropriate), the discharge of open loop scrubber water is not permitted in China’s DECAs.
SOUTH KOREA
South Korea established its own Domestic ECAs (DECAs). As announced by the Ministry of Oceans and Fisheries (MOF), they include South Korea’s five major port areas being Incheon, Pyeongtaek-Dangjin, Yeosu-Gwangyang, Busan and Ulsan. The precise coordinates for those areas are available from the Korean Register Technical Webpage.
Phased in over a two-year period from 2020 to 2022, the South Korean DECAs set a 0.1% sulphur cap while both berthed alongside and while navigating in the port area. As such, these DECAs should be considered as currently fully in force.
Alternative scrubber compliance methods are evidently permitted. This may include the use of open loop scrubbers but this needs to be carefully checked with local agents as regulation reportedly vary between ports.
OBSERVATION: In the above circumstances, it is suggested to Members that members operating vessels with scrubbers should not operate these units in port unless they are closed loop units or port authority permission has been obtained to operate an open loop unit in the closed loop mode.
CONCLUSION AND TAKEAWAY
The implementation of MARPOL Annex VI and its 2020 reduction of global marine fuel/bunker sulphur levels from 3.5% to 0.5% has been accomplished with remarkable efficiency. So too have the associated obligations for the establishment of MARPOL Annex VI ECAs and their on-going IMO coordinated expansion and enforcement.
Additional and independent sulphur reduction measures have also been taken by coastal states. In many cases, the enabling domestic regulations overlap and supplement MARPOL Annex VI regulations (e.g. Israel and Iceland). In other cases, the domestic regulations draw on the Annex VI provisions for 0.1% sulphur cap ECAs as a template for the creation of independent DECAs in designated areas. In both cases, the goal is the same which is to accelerate the protection of the environment and the inhabitants of coastal communities.
The risk for Members is that MARPOL Annex VI ECA expansion, regulatory overlap complexity or independent DECA regulation (not agreed and brought into force through IMO processes) can cause misunderstandings and the imposition of detention orders and heavy fines. A practical solution lies in a combination of knowledge, awareness and application; a process now greatly enhanced by access to the internet and AI tools and/or specialist maritime regulation compliance software. Local port agents and MMIA’s appointed P&I correspondents are also available to assist.
Members need to be attentive to the risks created by failures to fully comply with both MARPOL Annex VI ECA and regional DECA regulation and their associated 0.1% sulphur cap requirements. MMIA’s recommendations include the following:
- Together with your ship managers, DPAs, Masters and Chief Engineers, conduct a comprehensive review of your ISM Code Manuals and Procedures to ensure that they are in full accordance with the current requirements of MARPOL Annex VI. Any non-conformities should be rectified as a priority.
- Check to ensure that records of all MARPOL Annex VI relating bunker locations, type, analysis, quantity, location and use (inclusive of fuel change over locations, times and tank identification) are properly completed and retained both on board and at your ship manager’s offices. Any non-conformities should be rectified as a priority.
- Ensure that your ISM Code procedures for vessel navigation and voyage planning includes the obligation to clearly mark both MARPOL Annex VI ECA and regional DECA zones and requirements on the charts in use to ensure the requisite fuel changes to 0.1% sulphur content fuel are made before zone entry. This information should be notified well in advance to the Chief Engineer.
- For vessels using scrubber systems, check to ensure that the full details of the scrubber type (i.e. whether open or closed loop or an optional open/closed loop system) are known and posted and any port operation restrictions are understood by all of the crew. Further, that the scrubber system has been recently tested and certified as producing resultant exhaust emissions not higher than would be experienced from 0.1% sulphur content fuel.
- Prior to entry into any port, check with local agents and/or directly with the port authorities to obtain clear and preferably written advice as to local requirements in relation to the applicable fuel sulphur cap or alternative scrubber system use and any constraints on its operation.
