Supplementary Fund Protocol 2003: third-tier oil pollution

Background: the post-Erika and post-Prestige political driver

The Supplementary Fund Protocol 2003 cannot be understood outside the political shock produced by two consecutive European casualties at the turn of the millennium. The Erika, a 25-year-old single-hull product tanker registered in Malta and chartered to TotalFinaElf, broke in two off the coast of Brittany on 12 December 1999 in heavy weather, releasing approximately 19,800 tonnes of heavy fuel oil that contaminated some 400 kilometres of French coastline from the Loire to the Cotentin peninsula. The Prestige, a 26-year-old single-hull tanker registered in the Bahamas, suffered hull damage off Cape Finisterre on 13 November 2002, was refused a place of refuge by the Spanish, Portuguese, and French authorities, was towed seaward, and broke up on 19 November 2002 some 250 kilometres west of Vigo, releasing roughly 63,000 tonnes of heavy fuel oil that affected the Atlantic coasts of Spain, Portugal, and France.

Both casualties exposed a structural weakness in the layered compensation regime as it then existed. The combined CLC 1992 plus Fund 1992 cap stood at 135 million SDR per incident in 1996, raised by the 2000 amendments to the Fund Convention to 203 million SDR with effect from 1 November 2003. Erika claims, including clean-up, property damage, economic loss in the tourism and fisheries sectors, and environmental restoration, eventually approached EUR 388 million in admissible amounts and led the IOPC Fund Executive Committee to apply a pro-rata payment percentage, paying claimants only a fraction of their assessed claim until total liability had been determined. Prestige claims would in due course exceed EUR 1 billion including state expenditure, with Spain pursuing the registered owner Mare Shipping Inc. and the London Steam-Ship Owners’ Mutual Insurance Association in parallel proceedings in Spain, the United Kingdom, and the United States.

The political demand inside the European Union, articulated in the Erika I, Erika II, and Erika III packages of maritime safety legislation between 2000 and 2009, was explicit: the third tier was needed to ensure that victims could be paid in full and on time for any plausible single-tanker incident in European waters, without recourse to litigation against the registered owner, the cargo owner, the classification society, or the flag State. The IOPC Funds Working Group on Compensation, established by Resolution of the 1992 Fund Assembly in October 2000, examined three options: a sharp upward revision of the Fund 1992 cap by amendment, an entirely new instrument outside the IOPC family, and the optional supplementary tier ultimately adopted. Option three preserved the integrity of the existing Fund 1992 membership while allowing those States with high-value coastlines or large oil-receiver bases to opt into a higher cap.

2003 adoption and 2005 entry into force

The Diplomatic Conference on the Establishment of a Supplementary Fund for Compensation for Oil Pollution Damage convened at IMO Headquarters at 4 Albert Embankment, London, from 12 to 16 May 2003. The Conference was attended by delegations from 76 States and observers from 13 intergovernmental and non-governmental organisations, including the International Group of P&I Clubs, the International Tanker Owners Pollution Federation (ITOPF), the Oil Companies International Marine Forum (OCIMF), and the Cruise Lines International Association. The Final Act was signed on 16 May 2003, opening the Protocol for signature in London from 31 July 2003 to 30 July 2004 and thereafter for accession.

Article 21 of the Protocol set the entry-into-force threshold at the deposit of instruments of ratification, acceptance, approval, or accession by at least eight States that have received in total a quantity of at least 450 million tonnes of contributing oil during the preceding calendar year. The threshold was met when Norway deposited its instrument on 3 December 2004. The Protocol entered into force on 3 March 2005, exactly three months after that deposit, in accordance with Article 21(1).

The first eight Contracting States were Denmark, Finland, France, Germany, Ireland, Japan, Norway, and Spain. The Republic of Korea acceded in 2010, the Philippines in 2020, and Türkiye in 2024. The text is published as the consolidated 2003 Protocol in the IOPC Funds Legal Framework collection and in the IMO Treaty Series. The Protocol is read together with the 1992 Fund Convention as a single instrument; the operative provisions of the 1992 Fund Convention apply mutatis mutandis to the Supplementary Fund unless the Protocol provides otherwise.

Purpose: top-up compensation above CLC plus Fund 1992

The Supplementary Fund’s exclusive function is residual compensation. Article 4(1)(a) of the Protocol provides that the Supplementary Fund shall pay compensation to any person suffering pollution damage if such person has been unable to obtain full and adequate compensation for an established claim under the terms of the 1992 Fund Convention because the total damage exceeds, or there is a risk that it will exceed, the maximum amount of compensation payable under Article 4(4) of the 1992 Fund Convention in respect of any one incident.

The mechanism is strictly vertical. The Supplementary Fund doesn’t provide an alternative cause of action, doesn’t modify the admissibility criteria of the 1992 Fund Convention, doesn’t relax the 1992 Fund’s geographic scope, and doesn’t extend the limitation period beyond the three-year and six-year bars in Article 6 of the 1992 Fund Convention. A claim that fails the Sapphire criteria for admissibility under Fund 1992 fails equally under the Supplementary Fund. A claim that is time-barred against Fund 1992 is time-barred against the Supplementary Fund. A claim outside the geographic scope of Fund 1992 is outside the geographic scope of the Supplementary Fund. The only difference is the higher aggregate cap.

The practical consequence in claims handling is that the same claim form, the same supporting documentation, the same IOPC Funds claims-handler decision all apply. A claimant submits one file, the IOPC Funds Secretariat assesses admissibility and quantum once, and the only operational question for the Director is whether the aggregate of admissible claims exceeds the Fund 1992 cap, in which case the residual amount up to the Supplementary Fund ceiling is paid from Supplementary Fund resources rather than Fund 1992 resources.

Three-tier compensation architecture

The three instruments operate as a single sequential waterfall. The table below summarises the caps and trigger conditions for each tier, using the SDR figures that apply to incidents occurring on or after 1 November 2003 and in States Party to the 1992 Fund Convention and the Supplementary Fund Protocol.

The CLC 1992 limit for any single ship is calculated as 3 million SDR plus 420 SDR per GT above 5,000 GT, subject to a maximum of 59.7 million SDR for ships up to roughly 140,000 GT; above 140,000 GT the formula produces limits above 59.7 million SDR to a ceiling of 89.77 million SDR for ships of 140,000 GT or more. Fund 1992 tops up above that amount to the 203 million SDR combined ceiling. The Supplementary Fund adds a third layer from 203 million SDR to 750 million SDR. The 750 million SDR aggregate is inclusive of all three tiers’ contributions; it is not an additional 750 million SDR on top of the other two.

The arithmetic is straightforward: if total admissible claims reach, say, 500 million SDR and the CLC layer pays 89.77 million SDR and Fund 1992 pays 113.23 million SDR to reach the 203 million SDR combined ceiling, the Supplementary Fund pays the residual 297 million SDR, for a combined payout of 500 million SDR. Where claims exceed 750 million SDR, the Director applies a pro-rata percentage of 750 million divided by the aggregate of admissible claims and pays each claimant that fraction of their assessed amount.

Maximum compensation: 750 million SDR per incident inclusive

Article 4(2)(a) of the Protocol fixes the aggregate ceiling at 750 million SDR per incident, inclusive of the amounts payable under CLC 1992 and Fund 1992. The arithmetic of the ceiling is strictly subtractive. If the registered owner pays the full CLC limit of, for example, 89.77 million SDR for a 140,000 GT tanker, and Fund 1992 pays the residual amount up to its 203 million SDR aggregate cap, then the Supplementary Fund’s exposure on that incident is at most 750 minus 203 equals 547 million SDR.

At an SDR-USD rate near 1.32 in 2026, the 750 million SDR cap converts to approximately USD 990 million. At an SDR-EUR rate near 1.21, the cap is about EUR 907 million. The cap is denominated in SDR rather than any single national currency to avoid the cap eroding through bilateral exchange-rate movement; the SDR basket of US dollar, euro, Chinese renminbi, Japanese yen, and pound sterling provides a more stable real-terms benchmark than any one component.

The cap is not a per-claimant cap, not a per-Member-State cap, and not a per-cause-of-action cap. It is a single aggregate ceiling per incident. If admissible claims exceed the cap, the Director applies a pro-rata payment percentage equal to the cap divided by the aggregate of admissible claims and pays each claimant that percentage of their assessed claim. The pro-rata percentage is reviewed periodically as new claims are admitted and as final court determinations replace provisional Secretariat assessments.

Contributor architecture: dual-Protocol Member States

The Supplementary Fund’s contributor base is structurally narrower than that of Fund 1992. Article 18 of the Protocol provides that only oil receivers in States Party to the Supplementary Fund Protocol are liable to contribute. A State Party to the 1992 Fund Convention but not to the Supplementary Fund Protocol receives the benefits of Fund 1992 alone; its oil receivers don’t contribute to and its claimants don’t benefit from the Supplementary Fund.

The mechanism of contribution mirrors Fund 1992: a person in a Contracting State who has received in total quantities exceeding 150,000 tonnes of contributing oil (crude oil and heavy fuel oil) carried by sea to ports or terminal installations in that State during the preceding calendar year is a qualifying contributor. Receipts include all contributing oil received from sea by any port or terminal installation, irrespective of the nationality, registry, or beneficial ownership of the carrying ship. Receipts in a Contracting State by a person other than a contributor must nevertheless be reported by the State to the IOPC Funds Secretariat for transparency and audit.

Article 14 of the Protocol introduces a minimum receipts mechanism to address the concern of small Member States that no oil receiver above the 150,000 tonne threshold would be present in their territory. Each State Party undertakes to ensure that any person in its territory who receives contributing oil in such quantities that the person, but for the existence of an associated company, would be liable to contribute, shall be deemed to be a contributor. This anti-fragmentation rule prevents corporate restructuring designed to keep individual receiver entities below the 150,000 tonne threshold.

A State that has ratified the Supplementary Fund Protocol but whose oil receivers have not in aggregate received the 1 million tonne minimum in any year is required by Article 14 to nominate a fictitious contributor receiving exactly 1 million tonnes, on whose behalf the State itself contributes. This rule ensures that every Supplementary Fund Member State carries at least a minimum share of the contribution burden and prevents free-riding by States with small or no oil-receiver presence.

Per-tonne contribution rate

The Supplementary Fund Secretariat, which is operationally the same staff as the IOPC Fund 1992 Secretariat, calculates the per-tonne contribution rate annually based on the Director’s estimate of the Fund’s cash needs for the contribution year. The rate is set at the level required to cover assessed claims, expected administrative expenditure, and any working capital cushion authorised by the Supplementary Fund Assembly, less any carry-over balance from prior years.

In years with no major incidents the rate is close to zero and contributions are levied only to cover Secretariat administrative costs and to maintain a small reserve. The Supplementary Fund’s administrative overhead is a fraction of Fund 1992’s because the Supplementary Fund piggybacks on Fund 1992’s claims-handling apparatus. Levies are typically issued in the first quarter of each contribution year and are payable within four months of issue.

Two distinct types of contribution exist. General contributions finance ongoing administration and maintenance of a working balance. Initial contributions are levied in respect of an individual major incident that has triggered the Supplementary Fund. The accounting separation between major-claims accounts and the general fund is maintained at the level of the Director’s Report to the Assembly and audited annually by the Fund’s external auditors.

A major incident triggering Supplementary Fund payment would push the per-tonne rate sharply upward in the following contribution year. For an incident producing 400 million SDR of Supplementary Fund exposure, distributed across a contributor base of, say, 600 million tonnes of annual qualifying receipts, the per-tonne rate for the following year would rise by roughly 0.67 SDR per tonne. That is still modest relative to the landed cost of crude oil but represents a real operational cost that refiners plan for in their operating budgets.

Relationship to IOPC Fund 1992

The Supplementary Fund operates alongside, not instead of, the IOPC Fund 1992. The two Funds are legally distinct entities under public international law, each with its own Assembly, its own contribution base, and its own balance sheet. They share a single Secretariat, a single Director, a single Executive Committee structure, and a single suite of operational claims-handling procedures.

The waterfall is: shipowner pays first up to the CLC limit; Fund 1992 pays next up to the combined CLC plus Fund 1992 cap of 203 million SDR; Supplementary Fund pays last up to the combined three-tier cap of 750 million SDR. A single incident in a Supplementary Fund Member State therefore engages all three tiers in sequence, and the Director’s Reports present the assessment, the admissible total, the cap arithmetic, and the proposed pro-rata payment percentage in a unified format.

A subtle point of practice is that payment in respect of a single claim can be split across the three sources without the claimant needing to lodge separate claims. The IOPC Funds Secretariat, acting on behalf of the Director of both Fund 1992 and the Supplementary Fund, allocates the disbursement to the appropriate tier based on the cap arithmetic at the time of payment. The receipt issued to the claimant identifies the source of each tranche.

Relationship to CLC 1992

The Supplementary Fund kicks in only after both the CLC and Fund 1992 ceilings are exhausted, but the relationship to CLC 1992 is more layered than a simple sequential trigger suggests. The Supplementary Fund follows the subrogation logic of Fund 1992: when the Supplementary Fund pays a claimant, it acquires by subrogation any rights that the claimant might have had against the registered shipowner, the CLC insurer (typically a Member of the International Group of P&I Clubs), the bareboat charterer, the manager, the operator, the cargo owner, the salvor, or any other party.

The CLC 1992 strict liability regime and its associated direct action against the insurer remain the front line of compensation. The CLC certificate carried by every tanker above 2,000 GT is the single most important compensation document on board. The blue card issued by the P&I Club to the registered owner, evidencing financial security up to the CLC limit, underpins the entire architecture. Where the registered owner is bankrupt, where no CLC certificate is in force, or where one of the closed Article III defences applies (act of war, intentional act of a third party, negligence of an authority responsible for navigation aids), Fund 1992 and then the Supplementary Fund step in.

The 2003 Protocol Article 5(3) replicates the broken-link clause of Fund 1992 in respect of the Supplementary Fund. A claimant has a direct cause of action against the Supplementary Fund without being required to exhaust remedies against the registered owner first, provided that the claim has been duly notified to the Director within the limitation period.

Per-state ratification status

By 2026 around 33 States are Party to the Supplementary Fund Protocol. The roster includes most major European maritime nations: the United Kingdom, Germany, France, the Netherlands, Belgium, Norway, Denmark, Sweden, Finland, Spain, Portugal, Italy, Greece, Ireland, Latvia, Lithuania, Estonia, Slovenia, Croatia, Hungary, the Czech Republic, and Poland. Asian Member States include Japan, the Republic of Korea, Singapore, the Philippines, and Türkiye. Non-European additional Members include Morocco and Barbados.

Notable non-Members include the United States, which is also not a Party to CLC 1992 or Fund 1992 and operates a parallel domestic regime under the Oil Pollution Act 1990 with its associated Oil Spill Liability Trust Fund. Canada is a Party to CLC 1992 and Fund 1992 but not to the Supplementary Fund Protocol, and operates a domestic third tier through the Ship-source Oil Pollution Fund funded by a per-tonne levy on oil imports. Australia is a Party to CLC 1992 and Fund 1992 but not to the Supplementary Fund Protocol. China is a Party to CLC 1992 and operates its China Oil Pollution Compensation Fund as a domestic instrument but is not a Party to either Fund 1992 or the Supplementary Fund Protocol. Russia is a Party to CLC 1992 but not to Fund 1992 or the Supplementary Fund Protocol.

The Supplementary Fund Member State map concentrates risk geographically in the eastern Atlantic, the Mediterranean, the Baltic, and the western Pacific. A major casualty in the Gulf of Mexico, the Caribbean, the South Atlantic, the Indian Ocean off Africa, or the South China Sea engages the Supplementary Fund only if the casualty occurs within the territorial sea or exclusive economic zone of a Supplementary Fund Member State.

Erika 1999 and Prestige 2002 post-incident payouts

The Erika incident remains the largest single drawdown on Fund 1992 in nominal terms. The IOPC Fund 1992 Executive Committee declared the level of payments at 50 percent in February 2000, raised to 60 percent in November 2000, then to 100 percent in October 2003 once it became clear that admissible claims would not exceed the Fund 1992 cap of 135 million SDR (the cap applicable to incidents occurring before 1 November 2003). Total compensation paid by the registered owner’s insurer Steamship Mutual and by Fund 1992 reached approximately EUR 130 million by the closure of the incident file. The criminal trial in France produced a judgment in 2008 against Total, the classification society RINA, the registered owner, and the manager for a combined criminal fine and civil damages of around EUR 200 million, of which the EUR 153 million civil component was paid outside the IOPC framework.

Erika didn’t formally trigger Supplementary Fund payments because the Supplementary Fund Protocol entered into force on 3 March 2005, after the Erika incident, and isn’t retroactive. France acceded to the Protocol in advance of entry into force; the Supplementary Fund applies only to incidents occurring on or after the date the Protocol enters into force in respect of the relevant Member State. Erika nonetheless was the principal political driver of the Protocol and is treated in the IOPC Funds annual reports as the case study that justified the Protocol’s existence.

The Prestige incident is more complex. Spain was a Party to Fund 1992 at the time of the incident on 13 November 2002 but not yet to the Supplementary Fund Protocol, which hadn’t entered into force. The IOPC Fund 1992 Executive Committee declared the level of payments at 15 percent in May 2003, raised in stages to 30 percent in October 2008, and ultimately the Spanish Supreme Court judgment of 14 January 2016 determined liability against the master Captain Mangouras, the registered owner Mare Shipping, and the London Steam-Ship Owners’ Mutual Insurance Association. Spain pursued enforcement in the United States and the United Kingdom for amounts well in excess of the Fund 1992 cap, demonstrating in real time the inadequacy that the Supplementary Fund was designed to remedy.

Hebei Spirit 2007: Supplementary Fund triggered

The Hebei Spirit incident on 7 December 2007 off Daesan in the Republic of Korea is the first major case in which the Supplementary Fund Protocol was triggered in its full operational form. The Hong Kong-registered VLCC Hebei Spirit was at anchor when struck by a runaway crane barge being towed by the tug Samsung T-5. Approximately 10,900 tonnes of crude oil were released, contaminating the Taean coast and affecting roughly 70 kilometres of shoreline.

The Republic of Korea acceded to the 1992 Fund Convention in 1992 and to the Supplementary Fund Protocol in 2010, with effect for incidents from 6 May 2010. Hebei Spirit, occurring on 7 December 2007, was covered by Fund 1992 alone in the first instance. The aggregate of admissible claims rose over time as Korean fisheries, tourism, mariculture, and clean-up claims were assessed. The IOPC Fund 1992 Executive Committee declared the level of payments at 35 percent in October 2008, then 100 percent in October 2014 once final court determinations had reduced the aggregate of admissible claims to below the cap. A separate tranche of compensation was paid by the limitation fund constituted by Samsung Heavy Industries as the towage interest.

The case is treated in the IOPC Funds literature as a template for the next event in a Supplementary Fund Member State, demonstrating both the operational pattern of joint Fund 1992 and Supplementary Fund handling and the importance of timely accession to the Protocol before a major incident strikes. Korea’s accession in 2010 reflected lessons learned from Hebei Spirit and from the simultaneous review of the regional oil-receiver contribution profile.

Sanchi 2018: China not a contributor

The Sanchi incident on 6 January 2018 in the East China Sea is the textbook example of a major casualty outside the Supplementary Fund’s reach. The Iranian-flagged Suezmax tanker Sanchi, carrying approximately 136,000 tonnes of condensate from Iran’s South Pars field to Daesan in the Republic of Korea, collided with the Hong Kong-flagged bulker CF Crystal in international waters approximately 160 nautical miles east of Shanghai. Sanchi caught fire, drifted for eight days while burning, and sank on 14 January 2018 with the loss of all 32 crew.

China is a Party to CLC 1992 but not to Fund 1992 or to the Supplementary Fund Protocol. The Republic of Korea is a Party to all three instruments. The casualty occurred in international waters but the resulting pollution affected primarily Chinese and Japanese coastal interests. Because China isn’t a Fund 1992 Member State, no IOPC compensation was payable in respect of damage in China; recourse was limited to the Iranian National Iranian Tanker Company as registered owner and to the CLC insurer. Japan, as a Fund 1992 and Supplementary Fund Member State, in principle had access to the IOPC architecture for any damage to Japanese coastal interests but actual claims fell well below the Fund 1992 cap and the Supplementary Fund wasn’t engaged.

Sanchi crystallised an enduring policy debate about the gap between IMO oil-pollution liability instruments and major non-Party States in Asia. China’s domestic China Oil Pollution Compensation Fund is a national instrument financed by a levy on oil imports and provides compensation for pollution damage in Chinese waters, but its scope, cap, and procedural rules are domestic rather than international.

Princess Empress 2023 and recent incidents

The MT Princess Empress incident on 28 February 2023 off Naujan, Oriental Mindoro, in the Philippines, is the most recent major casualty engaging the IOPC architecture in a Supplementary Fund Member State. The Philippines-flagged tanker, carrying approximately 800,000 litres of industrial fuel oil, sank in deep water with subsequent oil release affecting the Verde Island Passage marine biodiversity corridor, the Mindoro coastline, and the western Visayas. The Philippines acceded to the Supplementary Fund Protocol in 2020, so the incident engages all three IOPC tiers.

The IOPC Funds 1992 Fund Executive Committee and the Supplementary Fund Assembly reviewed claim admissibility throughout 2024 and 2025. Damage assessment, including environmental restoration of coral reefs and seagrass beds, mariculture losses, fisheries losses, and clean-up costs, was ongoing into 2026. The total admissible claim wasn’t expected to exceed the Fund 1992 cap, but the Supplementary Fund’s procedural readiness was tested in the assessment phase and the Funds’ cooperation with the Philippine Coast Guard and the Philippine Department of Environment and Natural Resources demonstrated the operational integration of the third tier.

Several smaller incidents in 2024 and 2025 in Supplementary Fund Member States were notified to the Secretariat but didn’t trigger payment under any tier because total damage fell within the registered owner’s CLC limit and was paid directly by the P&I insurer.

Per-state contribution magnitudes

The Supplementary Fund’s contribution base reflects the underlying geography of seaborne oil imports into Member States. Japan is consistently the largest single contributor because Japanese oil receivers import approximately 130 million tonnes of crude oil and heavy fuel oil per year, virtually all by sea. The Republic of Korea is the second-largest contributor with approximately 100 million tonnes of seaborne oil receipts. France ranks third with approximately 60 million tonnes. The Netherlands ranks fourth with approximately 50 million tonnes through the Rotterdam complex. Germany ranks fifth with approximately 45 million tonnes including refinery feedstock.

The combined contributions from these five States account for roughly 80 percent of total Supplementary Fund contribution receipts in any given year. The remaining 20 percent is distributed across the smaller Member States including Spain, Italy, Belgium, Greece, the Nordic countries, the Baltic States, Singapore, and the Philippines. The IOPC Funds Annual Report tabulates gross contribution receipts by Member State for each contribution year and is the authoritative public record of contributor magnitudes.

The per-tonne rate for the Supplementary Fund is typically a small fraction of the Fund 1992 rate in the same year because the Supplementary Fund engages only on the largest incidents, of which there are few. Recent years have seen Supplementary Fund per-tonne rates close to zero, with contributions levied principally to maintain a working balance and cover administration.

IOPC Funds joint governance

The Supplementary Fund Protocol Article 22 establishes a Supplementary Fund Assembly consisting of all Contracting States. The Assembly elects an Executive Committee, approves the budget, sets contribution levels, appoints the auditors, and approves the Director’s Report on claims handling. The Supplementary Fund Assembly meets back-to-back with the 1992 Fund Assembly each October at IMO Headquarters in London, with delegations from Member States nominating the same persons to both fora.

The Director is elected by the 1992 Fund Assembly and serves jointly as Director of the 1992 Fund and the Supplementary Fund. The Director’s tenure is four years renewable once. The Director exercises the same statutory functions in respect of the Supplementary Fund as in respect of Fund 1992: claims assessment, reporting to the Assembly, conduct of subrogation proceedings, signature of contracts, and external representation of the Funds.

The Secretariat is shared between Fund 1992 and the Supplementary Fund. Approximately 30 staff in the IOPC Funds Secretariat in London handle both Funds without functional separation. Cost-allocation between the two Funds is governed by the Service Level Agreement between the two Assemblies, which apportions Secretariat expenditure on the basis of estimated workload and the relative volume of contributions.

Working Group post-Prestige reforms

The Prestige incident triggered a sustained programme of review and reform within the IOPC Funds. The Working Group on the Implementation of the Conventions (WGIC) was established by the 1992 Fund Assembly in October 2003, in parallel with the establishment of the Supplementary Fund Protocol, to examine systemic issues in compensation arrangements. The Working Group reported on a range of topics across multiple meetings between 2003 and 2010.

Key recommendations included: clarification of the causation test for pure economic loss claims, particularly tourism and downstream fisheries claims; standardisation of claim documentation requirements across Member States; development of contingency planning protocols between the Funds and national administrations; review of the broken-link clause in cases where the registered owner’s CLC certificate is invalid; and consideration of the scope of pollution damage including environmental restoration claims.

A separate post-Prestige initiative was the Sea Empress reasoned-decisions practice, under which the Director publishes reasoned decisions on contested claims to provide guidance to claimants and Member States on admissibility criteria. The reasoned decisions are a key reference for P&I Clubs, claimants, and national administrations preparing for major casualties.

Comparison with HNS Convention 2010

The HNS Convention 2010, formally the 2010 Protocol to the International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances by Sea, applies a parallel architectural pattern to the IOPC regime but with a different scope. HNS covers damage from hazardous and noxious substances other than persistent oil, including chemicals, LPG, LNG, and packaged dangerous goods. HNS has its own two-tier structure: a shipowner’s strict liability layer supported by compulsory insurance, and a Fund layer financed by HNS receivers in Member States.

The differences from the IOPC three-tier regime are structural. HNS uses two tiers rather than three. The HNS Fund cap is 250 million SDR per incident, well below the Supplementary Fund’s 750 million SDR. The HNS Fund maintains separate contribution accounts for persistent oil, non-persistent oil including LNG and LPG, other bulk solids and liquids, and a general account, reflecting the heterogeneity of HNS cargoes. The 2010 Protocol entered into force on 14 April 2025 after meeting its accession threshold; ratification has been comparatively slow because of the receiver-reporting burden and the segmented account structure.

For an integrated maritime liability programme, the IOPC three-tier regime and the HNS two-tier regime are complementary rather than overlapping. A persistent-oil cargo casualty in a Member State that is Party to both regimes engages the IOPC tiers; an HNS cargo casualty engages the HNS regime. Mixed cargoes raise factual questions about which regime applies, resolved by reference to the predominant pollutant.

Commercial implications: oil-receiver levy and refining margin

The Supplementary Fund contribution levy is a direct cost on oil refiners in Member States. A Japanese refiner importing 30 million tonnes of crude per year carries a contribution liability that varies year by year with the per-tonne rate but is typically a few cents per tonne in normal years and could reach a dollar or more per tonne in the year following a major incident. The levy is included in the landed cost of the cargo and ultimately passes through to consumers in the form of a small premium on refined product prices.

The pricing differential between Brent crude (delivered into European Union and UK refineries that are predominantly in Supplementary Fund Member States) and WTI crude (delivered into US refineries outside the IOPC architecture) reflects, among many other factors, the regulatory burden differential. The IOPC contribution component of this differential is small relative to the overall Brent-WTI spread but is stable and predictable, embedded in the operating cost structure of the receiving refiner.

Insurance markets view the Supplementary Fund as a risk-mitigation institution that limits the maximum public-sector pollution claim against a tanker owner and its P&I Club. The CLC limit caps the registered owner’s exposure; Fund 1992 and the Supplementary Fund socialise the residual cost across the oil-receiver community in Member States. From a P&I Club perspective the Supplementary Fund reduces the political pressure to revisit the CLC limit upward, because aggregate compensation is already at a level that satisfies most political audiences after a major incident.

Comparison with US OPA 90 and Oil Spill Liability Trust Fund

The United States operates a distinct domestic architecture under the Oil Pollution Act of 1990 (OPA 90), enacted in the wake of the Exxon Valdez casualty of 24 March 1989. OPA 90 imposes strict liability on the responsible party (typically the registered owner) for removal costs and damages, with statutory limits that are higher than CLC 1992 and that can be broken in cases of gross negligence, wilful misconduct, or violation of federal regulations. The 2006 amendments raised the OPA 90 limits to USD 22 million per incident for tank vessels above 3,000 GT, plus USD 3,000 per gross ton above 3,000 GT, with periodic adjustment for inflation.

Above the responsible party’s limit the Oil Spill Liability Trust Fund (OSLTF) operated by the US Coast Guard National Pollution Funds Center provides up to USD 1 billion per incident for removal costs and damages, with a USD 500 million sub-limit on natural resource damage assessment. The OSLTF is funded by an excise tax on petroleum at approximately USD 0.09 per barrel as of 2026, levied on domestic crude production and on imported petroleum products.

The structural differences from the IOPC architecture are substantive:

• OPA 90 limits are breakable in cases of fault, exposing the responsible party to unlimited liability; CLC 1992 limits are practically unbreakable except in cases of intent or recklessness with knowledge.
• The OSLTF cap of USD 1 billion is broadly comparable to the Supplementary Fund cap of 750 million SDR at 2026 exchange rates, but the OSLTF has no per-claimant or per-incident cap on natural resource damages beyond the federal sub-limit.
• The OPA 90 regime preserves state law claims in addition to federal law, enabling state attorneys general to pursue separate actions for state-specific damages; the IOPC regime is exclusive in respect of pollution damage covered by CLC and Fund Conventions.
• The OPA 90 regime doesn’t require compulsory insurance certification in the same form as the CLC blue card, but does require certificates of financial responsibility demonstrating the responsible party’s capacity to meet OPA 90 limits.
• The OSLTF is funded by a per-barrel tax, distributed across all petroleum throughput; the Supplementary Fund is funded by a per-tonne contribution levied only on receivers above 150,000 tonnes per year.

For tanker owners trading globally, the practical consequence is that an incident in US waters engages OPA 90 and potentially state law in addition to the OPA 90 framework, whereas an incident in waters of a Supplementary Fund Member State engages the IOPC three-tier regime as a single coordinated architecture. The two regimes aren’t mutually exclusive; a single tanker traverses both regulatory environments in the course of a typical voyage and must satisfy the documentation requirements of each.

Limitations

The Supplementary Fund Protocol 2003 leaves several gaps that practitioners must account for.

Geographic exclusions. The three-tier IOPC regime applies only to pollution damage in the territory, territorial sea, or exclusive economic zone of a State Party to CLC 1992. A casualty in international waters beyond any State’s exclusive economic zone produces no entitlement to IOPC compensation unless pollution reaches the coast or the EEZ of a Member State. The Supplementary Fund adds no geographic extension; it applies only where Fund 1992 applies.

Non-Member-State claimants. A claimant in a State that is Party to CLC 1992 and Fund 1992 but not to the Supplementary Fund Protocol receives a maximum of 203 million SDR in combined compensation, not 750 million SDR. The Supplementary Fund’s higher ceiling is exclusively for claimants in Supplementary Fund Member States.

Retroactivity bar. The Protocol applies only to incidents occurring on or after the date of its entry into force in respect of the relevant Member State. States that ratified after 3 March 2005 have no Supplementary Fund entitlement for incidents that occurred before their own ratification took effect. The Prestige and Erika incidents predated entry into force and received no Supplementary Fund payment, despite being the political justification for the Protocol.

Cap sufficiency. 750 million SDR represented approximately USD 1 billion at the time of drafting. Inflation since 2003 has eroded the real-terms value of a fixed SDR cap. A very large casualty in a densely populated coastal area, involving a ULCC of 300,000 GT carrying 3 million barrels of crude, could in principle produce admissible claims exceeding 750 million SDR, particularly where environmental restoration of protected marine habitats is included. The IOPC Funds Working Group has periodically examined whether the cap should be raised, but no amendment has been adopted.

Non-oil cargoes. The Supplementary Fund Protocol covers only persistent oil and heavy fuel oil within the scope of CLC 1992. Chemical, LNG, LPG, and other HNS cargo casualties are entirely outside its scope. A tanker carrying a blend of crude oil and condensate raises apportionment questions under the 1992 Fund Convention’s admissibility rules, which the Supplementary Fund inherits without modification.

Subrogation recovery limits. When the Supplementary Fund pays a claimant and acquires subrogated rights against the registered owner or the CLC insurer, recovery in practice is limited by the CLC cap and by the insolvency risk of the responsible party. The Fund’s subrogation is strongest where a solvent shipowner breached the CLC certification requirement; it is weakest where the casualty was caused by a bankrupt single-ship company with a disputed or exhausted P&I policy.

Pro-rata payment delay. In major incidents the Director cannot determine the final pro-rata payment percentage until all admissible claims have been assessed and final court determinations have replaced provisional assessments. Claimants may wait several years for full payment, receiving interim pro-rata payments that are subject to upward revision. The Erika incident required approximately three years from the casualty to full payment on most claims.

AEO questions and answers

Q: What is the total compensation available under the three-tier IOPC regime? The maximum combined compensation across all three tiers is 750 million SDR per incident, inclusive of the amounts payable under CLC 1992 and the IOPC Fund 1992. This figure is fixed by Article 4(2)(a) of the Supplementary Fund Protocol 2003. At a 2026 SDR-USD rate near 1.32, it is roughly USD 990 million.

Q: Is 750 million SDR on top of CLC and Fund 1992 payments, or does it include them? The 750 million SDR ceiling includes all three tiers. The Supplementary Fund pays the residual after CLC 1992 (up to roughly 89.77 million SDR for a large tanker) and Fund 1992 (up to the combined 203 million SDR ceiling) have paid. The Supplementary Fund’s own maximum exposure is therefore 750 minus 203 equals 547 million SDR.

Q: How many states have joined the Supplementary Fund Protocol? By 2026, approximately 33 States are Party. These include most major European maritime nations and key Asian states (Japan, Korea, Singapore, Philippines, Türkiye) but not the United States, Canada, Australia, China, or Russia.

Q: When was the Supplementary Fund Protocol adopted and when did it enter into force? The Protocol was adopted at an IMO Diplomatic Conference in London on 16 May 2003. It entered into force on 3 March 2005, three months after Norway deposited the eighth instrument of ratification on 3 December 2004, satisfying the Article 21 threshold of eight States with aggregate contributing-oil receipts of at least 450 million tonnes.

Q: Does a claimant need to file separately with the Supplementary Fund? No. A claimant submits a single claim file to the IOPC Funds Secretariat. The same Secretariat assesses admissibility and quantum once; the Director allocates payment across tiers based on the cap arithmetic. The claimant’s receipt identifies which tier funded each payment tranche.

Q: How is the Supplementary Fund financed? By per-tonne contributions from qualifying oil receivers in Member States, those receiving more than 150,000 tonnes of contributing oil by sea per year. The per-tonne rate is set annually by the Director to meet assessed claims and administrative costs. States where no single receiver exceeds 150,000 tonnes must still ensure their aggregate receipts above that threshold are reported; those with sub-1-million-tonne aggregate receipt totals nominate a fictitious contributor on whose behalf the State contributes.

See also

• CLC 1992: Civil Liability Convention for Oil Pollution Damage
• IOPC Fund 1992: International Oil Pollution Compensation Fund
• Bunkers Convention 2001: bunker oil pollution liability
• HNS Convention 2010: hazardous and noxious substances liability and compensation
• Wreck Removal Convention (Nairobi 2007)
• OPRC 1990 and HNS Protocol: oil-spill response cooperation
• MARPOL Annex I: Oil Pollution Prevention
• SOPEP regulation: shipboard oil pollution emergency plan
• MARPOL Convention overview
• Calculators

Related calculators

• CLC - Oil Pollution Compensation Limit
• Norway NOx Fund Levy
• IMO London Protocol - Dumping Prevention (Ocean)
• MARPOL Annex I/37 - Shipboard Oil Pollution Emergency Plan
• IMO OPRC 1990 - Oil Pollution Preparedness Response
• IMO Intervention 1969 - Oil Pollution Intervention
• IMO CLC - Civil Liability for Oil Pollution
• IMO Bunkers 2001 - Bunker Oil Pollution Liability