OSPAR Decision 2025/01 is the most significant regulatory development in exhaust scrubber compliance since IMO 2020. It creates a binding legal obligation on 15 North-East Atlantic coastal states to prohibit open-loop EGCS washwater discharge in their internal waters and port areas by 1 July 2027, and to extend that prohibition to EGCS discharge in any mode by 1 July 2029.
For ships trading through north-west European waters, this decision changes the operational picture fundamentally. Unlike the IMO parameter-based framework, which asks whether the washwater is clean enough to discharge, OSPAR Decision 2025/01 asks whether discharge is permitted at all. For a full overview of the washwater compliance framework and how geographic restrictions interact with the IMO monitoring requirements, see the exhaust scrubber washwater discharge monitoring explainer page.
| Key thing to remember OSPAR Decision 2025/01 is a binding decision, not a guideline or recommendation. Each of the 15 OSPAR Contracting Parties is legally obligated to implement national prohibition legislation by the deadlines set in the Decision. Operators trading in OSPAR waters do not need to wait for all implementing legislation to be in place to begin planning: the direction and timing are now fixed, and the operational changes required to comply take time to arrange. |
What Is the OSPAR Convention?
The OSPAR Convention is the regional treaty governing the protection of the North-East Atlantic marine environment. It was adopted in 1992 as a consolidation of two earlier conventions covering dumping at sea and land-based sources of marine pollution. OSPAR stands for Oslo and Paris, reflecting the locations of the predecessor conventions.
The OSPAR Convention covers the North-East Atlantic, including the waters of the North Sea, the Irish Sea, the English Channel, the Bay of Biscay and the waters around Iceland and the Barents Sea. It operates through the OSPAR Commission, which brings together the 15 Contracting Parties listed below.
| Belgium | Denmark | Finland | France | Germany |
| Iceland | Ireland | Luxembourg | Netherlands | Norway |
| Portugal | Spain | Sweden | Switzerland | United Kingdom |
OSPAR is a regional convention that operates to higher environmental protection standards than the global IMO baseline. OSPAR Contracting Parties can and do adopt measures that go beyond what the IMO framework requires. OSPAR Decision 2025/01 on EGCS discharge is one such measure.
What Is OSPAR Decision 2025/01?
OSPAR Decision 2025/01 is a formal binding decision of the OSPAR Commission adopted in 2025. It requires all 15 OSPAR Contracting Parties to implement national legislation prohibiting EGCS washwater discharge in internal waters and port areas within their jurisdiction according to a defined timeline.
The Decision was adopted following years of scientific review by OSPAR of the impacts of EGCS washwater discharge on the North-East Atlantic marine environment. The scientific evidence considered included studies on PAH accumulation in near-shore sediments, bioaccumulation in marine organisms and the cumulative impact of discharge by large numbers of scrubber-equipped vessels in busy North-East Atlantic shipping lanes.
The key features of OSPAR Decision 2025/01 are:
- It is a binding decision, not a recommendation — all 15 Contracting Parties are legally obligated to implement national prohibitions within the specified timescales
- It covers all modes of EGCS operation from 2029 — open-loop discharge, hybrid mode discharge and closed-loop bleed-off discharge — not just open-loop discharge
- It applies to internal waters and port areas initially, with a roadmap for considering extension to territorial seas after 2029
- It operates through national implementing legislation — each Contracting Party must enact measures within their own legal system to give effect to the Decision by the deadline
What Is the Timeline for OSPAR Decision 2025/01?
The table below sets out the key dates and requirements of OSPAR Decision 2025/01, and what each means for operators of scrubber-equipped ships trading in OSPAR waters.
| Date | What OSPAR Decision 2025/01 requires | What it means for operators |
| 2025 | OSPAR Decision 2025/01 adopted by the OSPAR Commission. Establishes the binding legal obligation on all Contracting Parties to implement national prohibitions according to the roadmap. | Binding on all 15 OSPAR Contracting Parties from adoption |
| 1 July 2027 | Deadline by which each OSPAR Contracting Party must have implemented national legislation prohibiting open-loop EGCS discharge in internal waters and port areas within their jurisdiction. | Less than two years away. Operators trading OSPAR waters must begin operational planning now. |
| 1 July 2029 | Deadline by which each OSPAR Contracting Party must have implemented national legislation prohibiting EGCS discharge in any mode in internal waters and port areas. Covers open-loop discharge, hybrid mode discharge and closed-loop bleed-off discharge. | A more significant constraint than the 2027 deadline. Closed-loop operation does not provide a route to continued discharge after 2029. |
| Post 2029 | OSPAR has adopted a roadmap to consider extending geographic coverage beyond internal waters and port areas to include territorial seas. No confirmed deadline for territorial seas phase at time of publication. | Ongoing discussions. Operators with scrubbers should monitor OSPAR Commission outputs for further developments. |
| The 2027 deadline is less than two years away The deadline for open-loop discharge prohibition in OSPAR internal waters and port areas is 1 July 2027. For operators trading regularly through North-East Atlantic ports, this means operational changes are required within the current planning horizon. Vessels that rely on open-loop discharge throughout their route will need to identify how they will comply: fuel switching, closed-loop operation with retained bleed-off, or shore reception. Leaving this assessment until 2026 will not leave adequate time for the necessary operational and commercial arrangements. |
What Geographic Area Does OSPAR Decision 2025/01 Cover?
OSPAR Decision 2025/01 applies to the internal waters and port areas of each OSPAR Contracting Party within the OSPAR Convention area. The OSPAR Convention area covers the North-East Atlantic, broadly encompassing:
- The North Sea and the waters between the UK, Scandinavia, Germany, the Netherlands, Belgium and France
- The English Channel and its approaches
- The Irish Sea and the waters around Ireland and the west coast of the UK
- The Bay of Biscay and the waters around the Iberian Peninsula (Portugal and Spain)
- The waters around Iceland
- The Arctic waters within the OSPAR area including Norwegian Svalbard waters
Internal waters are the waters landward of the baseline from which territorial sea is measured. These include ports, harbours, estuaries, rivers and inland waterways within the coastal state’s sovereignty. Port areas are specifically included in the OSPAR Decision and are the first operational point of impact for ship operators.
Territorial waters extend 12 nautical miles seaward from the baseline. OSPAR Decision 2025/01 does not require prohibition in territorial seas at the 2027 or 2029 deadline, but the OSPAR roadmap includes consideration of extension to territorial seas after 2029. This is a significant distinction: ships can in principle continue to discharge in open ocean and territorial waters after 2027 and 2029, but must stop discharge when entering internal waters and port areas.
| Internal waters include waters well offshore of the visible coastline The boundary of internal waters is not simply the shoreline. In areas with complex coastlines, archipelagos and semi-enclosed bays, the baseline can be drawn a significant distance offshore and the internal waters boundary lies further out to sea than operators may expect. Ships approaching ports in Norway, the UK, Ireland and other OSPAR states with complex coastlines should confirm the internal waters boundary for each specific port approach. |
Why Did OSPAR Adopt a Discharge Ban Rather Than Tighter Parameter Limits?
OSPAR considered two broad approaches to managing EGCS discharge in North-East Atlantic waters: tightening the washwater parameter limits to reduce the concentration of contaminants in each discharge, or prohibiting discharge in sensitive areas altogether.
OSPAR’s scientific review concluded that parameter-based limits alone were insufficient to address the cumulative impact of EGCS discharge in the North-East Atlantic. The key findings that informed the Decision were:
Cumulative impact in busy shipping lanes
The North-East Atlantic carries some of the highest-density shipping traffic in the world, particularly in the North Sea, the English Channel and approaches to major European ports. Individual vessel discharges that each individually meet the MEPC.259(68) or MEPC.340(77) parameter limits can collectively produce a cumulative load of PAH and other contaminants that cannot disperse effectively in the relatively enclosed and ecologically sensitive waters of the North-East Atlantic.
Near-shore accumulation
OSPAR scientific assessments identified accumulation of PAH compounds in near-shore sediments and marine organisms in areas with high EGCS discharge activity. In open-ocean conditions, washwater contaminants disperse relatively rapidly. In estuaries, harbours and near-shore waters with limited flushing, the same contaminants accumulate and persist.
Sensitive ecosystem protection
The North-East Atlantic contains a number of particularly sensitive marine ecosystems, including OSPAR-protected habitats, Marine Protected Areas and commercial fishery areas. The OSPAR Commission concluded that the precautionary principle supported a prohibition approach in internal waters and port areas rather than continued reliance on parameter-based control alone.
What Does OSPAR Decision 2025/01 Mean for Open-Loop, Hybrid and Closed-Loop Systems?
Open-loop EGCS
Open-loop systems discharge washwater continuously overboard. After the 2027 deadline, open-loop discharge will be prohibited in OSPAR internal waters and port areas. Open-loop vessels trading OSPAR routes must either fuel-switch on restricted legs or retrofit closed-loop capability to the EGCS.
Hybrid EGCS
Hybrid systems can operate in either open-loop or closed-loop mode. After the 2027 deadline, hybrid vessels must operate in closed-loop mode within OSPAR internal waters and port areas and must retain bleed-off for ashore disposal. After the 2029 deadline, closed-loop bleed-off discharge will also be prohibited in OSPAR internal waters and port areas — meaning hybrid vessels must also retain bleed-off or fuel-switch after 2029.
Closed-loop EGCS
Closed-loop systems produce only a bleed-off stream rather than a continuous overboard discharge. After the 2027 deadline, closed-loop vessels trading OSPAR routes are in a better position than open-loop vessels for the initial phase. However, after the 2029 deadline, closed-loop bleed-off discharge will also be prohibited in OSPAR internal waters and port areas. Closed-loop vessels will therefore also need shore reception arrangements or fuel switching capability for OSPAR legs after 2029.
What Are the Operational Options for Scrubber-Equipped Ships After 2027?
The table below summarises the main options available to operators of scrubber-equipped ships to manage compliance with OSPAR Decision 2025/01.
| Option | How it works | Considerations |
| Switch to compliant low-sulphur fuel for OSPAR legs | Switch from HSFO to LSFO or MGO when entering internal waters and port areas where open-loop discharge is or will be prohibited. | Operationally straightforward where the vessel can fuel-switch. Fuel cost differential between HSFO and LSFO or MGO must be factored into voyage economics. |
| Operate in closed-loop mode with retained bleed-off | Switch from open-loop to closed-loop EGCS mode within OSPAR internal waters and port areas. Retain bleed-off in the holding tank for disposal ashore. | Available only where the EGCS supports closed-loop operation. Requires sufficient holding tank capacity for the restricted leg. Bleed-off discharge will also be prohibited after 2029. |
| Shore reception of washwater and residues | Retain all washwater and EGCS residues onboard within restricted areas and deliver to a shore reception facility at the next compliant port. | Requires adequate holding capacity. Shore reception facility must be confirmed in advance. EGCS residue disposal must be recorded in the EGCS Record Book. |
| Remove the scrubber | For vessels where the scrubber economics no longer stack up given expanding restrictions, consider removing the EGCS and switching permanently to compliant fuel. | Significant capital and drydock cost. Relevant primarily for vessels where the scrubber is approaching end of service life or where route restrictions make scrubber operation increasingly uneconomical. |
Most operators trading OSPAR routes will use a combination of options: fuel switching for short port calls, closed-loop operation with shore reception for longer restricted legs, and retained scrubber operation in international waters where discharge is permitted. The right combination depends on the specific route, the vessel’s EGCS configuration, holding tank capacity and the shore reception infrastructure at ports on the route.
How Does OSPAR Decision 2025/01 Interact With MEPC.340(77)?
OSPAR Decision 2025/01 and MEPC.340(77) are separate regulatory instruments that address different aspects of EGCS compliance. They operate in parallel and both apply to affected vessels. For a full explanation of what MEPC.340(77) requires for washwater monitoring documentation and recording, see What Is MEPC.340(77) and How Does It Differ From MEPC.259(68)?.
The key interaction between the two instruments is in the evidence chain. Under MEPC.340(77), the EGCS Record Book must record EGCS operational events including mode changes and discharge stops. When a vessel enters OSPAR internal waters and stops discharge or switches to closed-loop mode, this must be recorded in the EGCS Record Book with the date, time and vessel position. This creates the position-linked evidence record that demonstrates the vessel stopped discharge before entering the restricted area.
A vessel that meets MEPC.340(77) monitoring and recording requirements but does not have a complete EGCS Record Book covering mode changes at the OSPAR boundary will have a compliance gap in its evidence chain during a port state control inspection.
What Should Operators Do to Prepare for OSPAR Decision 2025/01?
The checklist below sets out the key preparation actions for operators of scrubber-equipped ships trading in OSPAR waters. The 2027 deadline means that planning should begin immediately.
| Action | What to do | When |
| Map OSPAR exposure | Identify which vessels in the fleet regularly trade through OSPAR internal waters and port areas. This includes North Sea ports, English Channel, Irish Sea, Bay of Biscay and Scandinavian waters. | Now |
| Confirm EGCS mode capability | For each affected vessel, confirm whether the EGCS supports open-loop only, closed-loop only or hybrid operation. Closed-loop capability is essential for post-2027 compliance on OSPAR routes. | Now |
| Assess holding tank capacity | Confirm holding tank capacity for retained washwater on each OSPAR-exposed vessel. Assess whether capacity is sufficient for the longest restricted leg on the route. | Now |
| Confirm fuel switching capability | For vessels where closed-loop operation is not available, confirm fuel switching arrangements for OSPAR legs and the cost differential for voyage planning. | Now |
| Confirm shore reception availability | For each OSPAR port on the route, confirm that shore reception facilities are available for retained washwater and EGCS residues. | Before 2027 |
| Review EGCS Record Book procedures | Ensure EGCS Record Book entries cover mode changes, discharge suspensions and discharge resumptions with date, time and position. Position-linked records are essential for the evidence chain in restricted areas. | Now and ongoing |
| Monitor national implementing legislation | OSPAR Contracting Parties will implement the Decision through national legislation. Track developments in the flag state and each coastal state on the route. Implementation timelines and scope may vary between states. | Ongoing until 2027 and beyond |
| Review scrubber economics | For vessels where expanding restrictions significantly increase the cost or operational complexity of EGCS operation, review the scrubber economics against the current and projected fuel price differential. | Before capital expenditure decisions |
Rivertrace’s SMART ESM provides the continuous monitoring, data logging and evidence record that supports EGCS compliance in OSPAR waters and beyond. For more detail on the full geographic picture of where discharge restrictions currently apply, see Where Is Open-Loop Scrubber Discharge Banned or Restricted?.
What Is the Wider Regulatory Context for EGCS Discharge in 2026 and Beyond?
OSPAR Decision 2025/01 is the most significant development but it sits within a broader and continuing regulatory evolution. PPR 13 in February 2026 continued IMO discussions on potential global control measures for EGCS discharge, including discharge restrictions linked to Particularly Sensitive Sea Areas (PSSAs). PPR 14 has been invited to receive concrete proposals.
The direction of travel at both regional and global level is clearly towards more geographic restrictions, better evidence requirements and higher accountability for washwater discharge. Operators who position their EGCS compliance management as a core operational function now — rather than treating it as a documentation exercise — will be better placed to respond to further developments as they emerge.
Frequently Asked Questions
What is OSPAR Decision 2025/01?
OSPAR Decision 2025/01 is a binding decision of the OSPAR Commission adopted in 2025 that requires all 15 OSPAR Contracting Parties to implement national legislation prohibiting EGCS washwater discharge in internal waters and port areas by 1 July 2027 (open-loop discharge) and by 1 July 2029 (all-mode discharge including closed-loop bleed-off). It applies across the North-East Atlantic including the North Sea, English Channel, Irish Sea, Bay of Biscay and surrounding waters.
Which countries are covered by OSPAR Decision 2025/01?
The 15 OSPAR Contracting Parties are Belgium, Denmark, Finland, France, Germany, Iceland, Ireland, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Each is legally required to implement national legislation giving effect to the Decision by the specified deadlines. The exact scope of national implementing legislation may vary between states.
When does OSPAR Decision 2025/01 take effect?
The OSPAR Decision was adopted in 2025. OSPAR Contracting Parties must implement national legislation prohibiting open-loop EGCS discharge in internal waters and port areas by 1 July 2027, and all-mode discharge by 1 July 2029. The national implementing legislation of each Contracting Party will specify the exact scope and any transitional arrangements.
Does OSPAR Decision 2025/01 apply to closed-loop scrubbers?
Yes, from 2029. The 2027 deadline covers open-loop discharge. The 2029 deadline covers EGCS discharge in any mode, including closed-loop bleed-off discharge. From 2029, vessels operating closed-loop EGCS in OSPAR internal waters and port areas will not be able to discharge bleed-off overboard. Retained bleed-off must be stored onboard and delivered to a shore reception facility.
Does OSPAR Decision 2025/01 apply in territorial waters?
Not at the 2027 or 2029 deadlines. The Decision currently applies to internal waters and port areas only. The OSPAR roadmap includes consideration of extending geographic coverage to territorial seas after 2029, but no deadline has been confirmed for this phase at the time of publication. Discharge in international waters and territorial waters outside specific national restrictions continues to be governed by the IMO parameter-based framework.
What should scrubber-equipped ship operators do now to prepare?
Operators should immediately map which vessels trade through OSPAR internal waters and port areas, confirm EGCS mode capability and holding tank capacity, assess fuel switching options for restricted legs, confirm shore reception availability at OSPAR ports on the route, and review EGCS Record Book procedures for documenting mode changes and discharge stops at the OSPAR boundary. The 2027 deadline is less than two years away and planning should begin now.
Is OSPAR Decision 2025/01 the same as the IMO EGCS guidelines?
No. OSPAR Decision 2025/01 is a regional instrument that prohibits discharge in OSPAR internal waters and port areas regardless of washwater quality. The IMO EGCS guidelines, MEPC.259(68) and MEPC.340(77), are global frameworks that set the washwater parameter limits that must be met where discharge is permitted. Both apply to ships trading in OSPAR waters: the IMO guidelines define how to monitor and measure, and OSPAR Decision 2025/01 defines where discharge is not permitted at all.