MARPOL Annex VI Reg 18: bunker delivery note

Background: MEPC.176(58) 2008 amendments + Reg 18 introduction

The original 1997 text of MARPOL Annex VI , adopted at the International Conference of the Parties to MARPOL convened in London in September 1997, established a fuel-quality and documentation regime in Regulation 18 (Chapter 3 of the original Annex VI). The 1997 text required suppliers to provide a Bunker Delivery Note recording basic fuel characteristics and required ships to retain a representative sample. The 1997 BDN was a relatively short document and the sample-handling chain of custody was lightly specified, since the principal use of the data at that time was the 3.5% to 4.5% global cap with the original SECA limits of 1.5% and 1.0%, both of which could be verified by relatively coarse measurement.

By the late 2000s, the air-pollution chapter of Annex VI was being comprehensively revised because of the science of secondary sulphate aerosol, the increased ambition of the 0.50% global cap by 2020 (or 2025), the introduction of the North American ECA , and the introduction of the Tier I, II and III NOx regime under the rewritten Regulation 13. Regulation 18 also needed substantial strengthening: the BDN had to record sulphur content with sufficient precision to verify a 0.50% or a 0.10% cap, the sample had to be retained long enough for PSC and flag-state laboratory testing (typically 30-60 days from delivery to PSC sampling, plus 60-90 days for laboratory turnaround), and the chain of custody had to be tight enough that a non-compliant operator could not credibly dispute the sealed-sample test result.

The 2008 amendments to Annex VI were adopted by Resolution MEPC.176(58) on 10 October 2008, with entry into force on 1 July 2010. The 2008 amendments completely rewrote Regulation 18, adding Appendix V to Annex VI (the BDN minimum-content schedule), introducing the explicit 3-year on-board retention requirement for the BDN (Reg 18.6), the 12-month retention requirement for the representative sample (Reg 18.8.1), and the Party undertakings on suppliers, including a register of local fuel oil suppliers, now Regulation 18.9.1.

The sampling detail has since moved into guidelines rather than the regulation. MEPC.182(59) of 17 July 2009 set the original sampling guidelines. MSC-MEPC.2/Circ.18 of 11 July 2024, approved by MEPC 81 and MSC 108, replaced them and revoked MEPC.182(59): paragraph 6.1 places the sampling point at the receiving ship’s inlet bunker manifold with the sample drawn continuously, and paragraph 7.3 sets a container of not less than 600 ml. Resolution MEPC.250(66) of 4 April 2014 amended the IBC Code and has no bearing on Regulation 18.

MEPC.286(71), adopted 7 July 2017 and in force 1 January 2019, replaced the Appendix V supplier declaration with the three tick boxes now in use. MEPC.305(73), adopted 26 October 2018 and in force 1 March 2020, inserted “or carried for use” into Regulation 14.1, which is the carriage ban; it made no change to Regulation 18 or Appendix V. MEPC.324(75), adopted 20 November 2020 and in force 1 April 2022, added the in-use and onboard sampling points in Regulations 14.8 to 14.13 and replaced Appendix VI. MEPC.362(79) added the flashpoint as Appendix V item 9 from 1 May 2024, and MEPC.385(81) split Regulation 18.5 from 1 August 2025.

Reg 18 structure: BDN + sample + supplier registration

Regulation 18 has three operational pillars that together form the verification chain:

• The BDN is the paper or electronic document issued by the supplier and signed by both the supplier and the chief engineer. It records the fuel characteristics and is retained on board for 3 years and at the supplier’s office for at least 3 years. The BDN is the document that PSC officers inspect first.
• The representative sample is the physical sealed bottle of the actually delivered fuel, drawn at the manifold and retained on board for 12 months. The sample is the physical evidence that backs up (or contradicts) the BDN declaration.
• The supplier registration is the obligation of the supplier to register the BDN with the port state authority of the bunkering port, typically the flag administration of the port. The registration creates the supplier-side audit trail and is the basis on which a flag administration can verify that suppliers are not issuing BDNs for fuel that does not exist.

The three pillars together support a two-way verification: the BDN is checked against the on-board sample (manifold-sample sulphur should match BDN-declared sulphur), and the BDN is checked against the supplier registration (the BDN reference number on board should match the supplier registration record). A discrepancy at either junction is a Reg 18 deficiency.

BDN content requirements: Appendix V, ten items

Appendix V of Annex VI lists the minimum content of the BDN required by Regulation 18.5.1. There is no IMO standard BDN form beyond it.

1. Name and IMO number of the receiving ship.
2. Port.
3. Date of commencement of delivery.
4. Name, address and telephone number of the marine fuel oil supplier.
5. Product name(s).
6. Quantity in metric tonnes.
7. Density at 15 degrees C (kg/m3).
8. Sulphur content (% m/m).
9. The flashpoint (degrees C) specified in accordance with standards acceptable to the Organization, or a statement that the flashpoint has been measured at or above 70 degrees C. Added by MEPC.362(79) from 1 May 2024, with a footnote to ISO 2719:2016, Procedure A for distillates and Procedure B for residual fuels.
10. A declaration signed and certified by the supplier’s representative that the fuel conforms to Regulation 18.3 and that its sulphur content does not exceed the Regulation 14.1 limit, the Regulation 14.4 limit, or a purchaser-specified limit. The third box applies where the purchaser has notified use with a Regulation 4 equivalent or under a Regulation 3.2 trial exemption.

A BDN reference number, the sample seal numbers, the delivery temperature and viscosity are common additions required by contracts or national rules, not by Appendix V. MEPC.1/Circ.875/Add.1 paragraph 11.6 recommends that seal details be recorded on the BDN.

For a low-flashpoint fuel or a gas fuel, Regulation 18.5.2 as amended by MEPC.385(81) requires items 1 to 6, the density measured by a method suited to the fuel with its temperature, and a supplier declaration of conformity with Regulation 18.3. Sulphur is given as a tested value or, with the port of supply authority’s agreement, as a statement that it is below 0.001% m/m. The unified interpretation in MEPC.1/Circ.795/Rev.8 of 24 July 2023 accepts a BDN in hard copy or electronic format .

BDN retention: 3 years on board

Regulation 18.6 of Annex VI requires the BDN to be kept on board, readily available for inspection at all reasonable times, and retained for three years after the fuel oil has been delivered on board.

The BDN is retained as a paper document in the original signed form, or as an electronic copy where the flag administration accepts electronic record-keeping. The on-board file is typically kept in the engine control room (ECR) or in the chief engineer’s office, organised chronologically by delivery date with a cross-reference index by BDN reference number. A loose-leaf binder is the most common physical format; some operators use PDF storage on the ship-management system.

The three-year period is a minimum; a company may keep BDNs longer as part of its bunker history file.

The supplier-side retention is parallel: the supplier must retain the BDN at its office for at least 3 years under Regulation 18.9.3.

MARPOL fuel oil sample: Reg 18.8.1, 12-month retention

Regulation 18.8.1 requires the BDN to be accompanied by a representative sample of the fuel oil delivered, taking into account the IMO guidelines. It is sealed and signed by the supplier’s representative and the master or officer in charge of the bunker operation on completion of bunkering, and retained under the ship’s control until the fuel oil is substantially consumed, and in any case for not less than 12 months from delivery. Regulation 2.1.22 defines it as the MARPOL delivered sample .

MSC-MEPC.2/Circ.18 of 11 July 2024 is the current sampling guideline. Paragraph 6.1 places the sampling point at the receiving ship’s inlet bunker manifold, with the sample drawn continuously throughout the delivery. Paragraph 7.3 sets a container volume of not less than 600 ml, filled to 90% plus or minus 5% and sealed. The circular revoked MEPC.182(59), whose 400 ml figure is out of date.

Sample types and retention summary

Sealing and chain of custody

Regulation 18.8.1 requires the sample to be sealed and signed by the supplier’s representative and the master or officer in charge on completion of bunkering. Appendix VI paragraph 2.2.3 requires the laboratory to reject a delivered sample whose seal was broken before receipt, so an intact seal is what gives the sample its evidential value.

The detail of seal numbering, labelling and witnessing is guidance and contract practice. MEPC.1/Circ.875/Add.1 of 9 November 2018 recommends witnessed sealing with unique seal numbers recorded and countersigned (paragraph 9.6) and seal details on the BDN (paragraph 11.6). BIMCO Bunker Terms 2018 clause 4(b) requires labels showing the vessel, the delivery facility, the product, the date and place, the point of sampling and the seal number, signed by the sellers’ representative and the master or authorized representative.

Sample-port location requirements and the three distinct sample points

MSC-MEPC.2/Circ.18 paragraph 6.1 places the Regulation 18.8.1 sample at the receiving ship’s inlet bunker manifold, drawn continuously throughout the delivery.

MEPC.324(75), in force 1 April 2022, added two further samples under Regulation 14.8. This creates three distinct sampling locations in the Reg 14/Reg 18 verification framework:

1. Manifold sample (Reg 18.8.1): the MARPOL delivered sample, drawn during delivery, sealed and retained 12 months. This is the primary enforcement instrument for the delivered fuel.
2. In-use sample (Reg 14.8): drawn from the fuel supply line between the service tank and the main engine (or auxiliary). This captures the fuel actually entering the engine and accounts for any blending or contamination between delivery and combustion.
3. Onboard sample (Reg 14.8): drawn from the service or storage tank. This captures the in-tank fuel at the time of inspection and may reflect a mixture of multiple deliveries.

PSC officers use the in-use and onboard sample points to verify ongoing Reg 14 compliance independent of the delivered-sample record. Where a vessel has mixed compliant and non-compliant fuel in a tank, or where a delivery postdates the last PSC inspection, the in-use sample is the most direct check. Appendix VI verifies the delivered sample under Part 1 with no test margin, and the in-use and onboard samples under Part 2 with the 0.59R margin.

The June 2018 BIMCO and IBIA Bunkering Guide describes collecting between 4 and 5 litres over the whole delivery period and decanting it into the MARPOL and commercial sample containers. Once sealed, the MARPOL and commercial samples are not interchangeable.

MEPC.182(59) of 2009 was the sampling guideline until MSC-MEPC.2/Circ.18 revoked it on 11 July 2024.

Appendix VI verification procedure: Part 1, Part 2 and the 0.53% and 0.11% margins

Appendix VI of Annex VI is the procedure for deciding whether a fuel oil sample has met the Regulation 14 limit. MEPC.324(75), adopted 20 November 2020 and in force 1 April 2022, replaced it in full, and the same text is carried in MEPC.328(76).

Part 1 verifies the MARPOL delivered sample. The laboratory splits it into two subsamples and averages the results as X. If X is equal to or less than the applicable limit, the fuel “shall be considered to have met the requirement”; if X is greater, it has not. Table 1 has no test margin, so a delivered sample at 0.51% against a 0.50% limit fails.

Part 2 verifies in-use and onboard samples. The averaged result Z is compared to the limit V plus 0.59R, where R is the reproducibility of the test method. Under paragraph 4.5.2, a result above V but at or below that margin has met the requirement. Table 2 gives the test margin values W exactly:

Results are reported to two decimal places, and paragraph 4.6 says the final results “shall be evaluated by the competent authority”. The procedure names ISO 8754:2003 run by a laboratory accredited to ISO/IEC 17025:2017 or equivalent; ISO 8754:2025 has since replaced the 2003 edition. No IMO text on the procedure uses a confidence level, and none sets a separate tolerance between the BDN figure and the sample result: Part 1 compares the sample to the Regulation 14 limit, not to the BDN.

ISO 8217 fuel-specification relationship (parallel but separate)

The ISO 8217 standard, Petroleum products - Fuels (class F) - Specifications of marine fuels, is the industry-standard fuel-quality specification that runs in parallel with the regulatory BDN regime but is legally distinct. Where the BDN is the regulatory document required by MARPOL, ISO 8217 is the commercial specification cited in the supplier-buyer fuel-supply contract.

ISO 8217 specifies fuel grades in two main families:

• Distillate fuels (Annex A), grades DMX, DMA, DMB, DMZ, with viscosity at 40 degrees C in cSt, sulphur in % m/m, and other parameters. DMA is the standard marine gas oil grade.
• Residual fuels (Annex B), grades RMA-10, RMB-30, RMD-80, RME-180, RMG-180, RMG-380, RMG-500, RMG-700, RMK-380, RMK-500, RMK-700, with viscosity at 50 degrees C in cSt, sulphur in % m/m, and other parameters. RMG-380 is the historical workhorse HFO and is now the most common VLSFO grade.

The BDN typically cites the ISO 8217 grade in field 6 (product name) and in field 12 (other parameters). PSC officers and class society surveyors use the ISO 8217 grade as a shorthand for the expected fuel parameters, but the regulatory parameters (sulphur, density, flash point) are those recorded on the BDN itself, not those of the ISO 8217 grade.

The relationship between ISO 8217 and Reg 18 is complementary but not identical:

• ISO 8217 specifies commercial-quality parameters (viscosity, water, ash, vanadium, sodium, aluminium-plus-silicon, total sediment) that are not regulated by MARPOL.
• Reg 18 requires the BDN to record sulphur, density and flash point, which are regulatory parameters; ISO 8217 also specifies these but with slightly different limits (ISO 8217 RMG-380 sulphur limit is the regulatory limit at the time, not necessarily the actual fuel sulphur).
• A fuel on-spec to ISO 8217 is not necessarily compliant with Reg 14: a 3.0% RMG-380 was on-spec to ISO 8217:2010 (with a 3.5% maximum sulphur) but is non-compliant with the 0.50% global cap.
• A fuel compliant with Reg 14 is not necessarily on-spec to ISO 8217: a 0.45% VLSFO with high cat-fines or stability problems may be compliant with Reg 14 but off-spec to ISO 8217 RMG-380.

The two regimes are therefore independent compliance checks: the BDN evidences Reg 14 compliance, the ISO 8217 test report (typically issued by a third-party laboratory such as DNV PS, VPS, Bureau Veritas Marine Fuel, or Lloyd’s Register FOBAS) evidences commercial-quality compliance, and a fuel must pass both to be commercially and regulatorily acceptable.

ISO 8217:2024 update: VLSFO + ULSFO + biofuels Annex F

The ISO 8217 standard was first published in 1987 and has been revised in 1996, 2005, 2010, 2017, and 2024. The ISO 8217:2024 revision, published in May 2024, is the most significant update since the 2010 edition and addresses three structural changes in the marine fuel market:

• The emergence of VLSFO (very-low-sulphur fuel oil) at 0.50% sulphur as the dominant non-ECA bunker grade post-2020. VLSFO is a heterogeneous category, with viscosity ranges from 30 cSt to 380 cSt and density ranges from 880 to 990 kg/m³. The 2024 edition introduces a VLSFO-specific characterisation within the existing residual-grade framework.
• The emergence of ULSFO (ultra-low-sulphur fuel oil) at 0.10% sulphur as the dominant ECA bunker grade. ULSFO is similarly heterogeneous.
• The emergence of bio-based marine fuels, including FAME blends (B7, B24, B30, B100) and HVO (hydrotreated vegetable oil). The 2024 edition adds a new Annex F specifying bio-component-blended fuel grades, with parameters for FAME content, oxidation stability, water content, and acid number.

The Annex F bio-fuel grades are particularly important under FuelEU Maritime and the IMO Net-Zero Framework , since both regulations incentivize the use of bio-fuels via the GHG intensity target. A FuelEU compliance pathway often involves a B30 blend (30% FAME by volume in residual or distillate), which the 2024 ISO 8217 Annex F specifies. The BDN under Reg 18 must record the bio-fuel content (where present), and the parallel FuelEU BDN under Article 9 must record the renewable share and the certified GHG intensity of the bio-fuel.

The 2024 edition also tightens the stability specification (total sediment after thermal aging, TSP) for VLSFO grades, in response to the persistent stability problems observed in 2019-2020 with early VLSFO blends. The test is now applied to aged fuel rather than fresh fuel, which is more representative of the fuel’s behavior after storage and heating on board.

Relationship to SOLAS Reg II-2/4.2 (flash point ≥60°C)

Item 9 of Appendix V records the flashpoint of the delivered fuel, with a footnote to ISO 2719:2016 (Pensky-Martens closed cup). The flash point must be at least 60 degrees C for fuel intended for main propulsion under SOLAS Regulation II-2/4.2.1.1, the International Convention for the Safety of Life at Sea (SOLAS) requirement on flammable liquids.

The 60-degree flash-point limit reflects the fire-safety boundary between flammable and combustible liquids in the IMO maritime classification. A fuel with flash point below 60 degrees C is flammable and requires special handling (inerting, vapour control, restricted handling locations); a fuel with flash point at or above 60 degrees C is combustible and may be handled in standard fuel-oil tanks and piping.

Marine gas oil (MGO) typically has a flash point of 60-70 degrees C (just above the limit), residual fuel oils typically have flash points of 80-120 degrees C (well above the limit), and bio-fuel blends typically have flash points in the same range as the host fuel. Some niche fuels (kerosene, jet-fuel-equivalent grades) have flash points below 60 degrees C and are not permitted for marine main propulsion under SOLAS unless special precautions are taken (typically only in naval vessels or in IGF-Code low-flashpoint-fuel installations).

MEPC.362(79) added the flashpoint to Appendix V from 1 May 2024. MSC.520(106), in force 1 January 2026, added SOLAS regulation II-2/4.2.1.6: before bunkering, the ship must be given a supplier declaration that the oil fuel conforms to the flashpoint requirement, naming the test method, and the BDN must show the flashpoint or a statement that it was measured at or above 70 degrees C. SOLAS regulation II-2/3.59 defines a confirmed case as an accredited laboratory result below 60 degrees C on a representative sample.

The flash point requirement is independent of sulphur content and independent of viscosity. A 0.10% ULSFO with flash point 55 degrees C is a SOLAS deficiency irrespective of its Reg 14 compliance; a 1.0% RMG-380 with flash point 90 degrees C is a Reg 14 deficiency (post-2020) but SOLAS-compliant. PSC inspections are therefore required to check both the flash point (SOLAS) and the sulphur content (MARPOL).

FuelEU Maritime and emissions reporting

FuelEU Maritime , Regulation (EU) 2023/1805, entered into force on 12 October 2023 and applies from 1 January 2025. Its GHG intensity calculation rests on the fuel quantities and types a ship reports, and the BDN is a primary source for those quantities, as it is for the IMO Data Collection System under Regulation 27 of Annex VI and the EU MRV Regulation. An error on the BDN therefore carries into each of those filings.

The draft IMO Net-Zero Framework and the BDN

The draft IMO Net-Zero Framework does not create a bunker delivery note regime. The BDN stays where it is, in regulation 18. The draft revised Annex VI approved at MEPC 83 in April 2025 adds a new Chapter 5, “Regulations on the IMO Net-Zero Framework”, at regulations 30 to 44, and that chapter touches the BDN exactly once, permissively.

The connecting provision is draft regulation 34 paragraph 3: the certified information in the Fuel Life Cycle Label (FLL) may accompany the bunker delivery note referred to in regulation 18, taking into account guidelines to be developed. The FLL is the fuel’s own sustainability document, carrying the GHG emission factors and the sustainability themes or aspects of the fuel, and it is certified by a recognized Sustainable Fuels Certification Scheme (SFCS) under regulation 34 paragraph 2. Under regulation 34 paragraph 5 the Secretary-General publishes the list of recognized SFCSs no later than 1 March 2027, and recognition is renewed every five years under paragraph 4.

Three consequences follow for a supplier or a chief engineer reading this today:

• There is no mandatory Chapter 5 field set bolted onto the regulation 18 BDN. The draft creates a separate certified document, the FLL, and permits it to travel with the BDN.
• There is no GFI penalty for a missing BDN in the draft chapter. The compliance consequence of unevidenced fuel runs through the attained annual GFI calculation in regulation 33 and the compliance approaches in regulation 36, not through the BDN.
• The carriage of the FLL alongside the BDN is drafted as a permission (may), so whether it becomes routine practice depends on the guidelines the Organization has not yet developed.

None of this is in force. MEPC/ES.2 of 14 to 17 October 2025 adjourned without adopting the draft, and MEPC 84 of 27 April to 1 May 2026 referred it to an intersessional working group, invited fresh amendments, and scheduled intersessional meetings for 1 to 4 September and 23 to 27 November 2026. The resumed Second Extraordinary Session is scheduled for 4 December 2026, subject to confirmation by MEPC 85. The chapter carries no resolution number, no adoption date and no entry-into-force date, so every provision described above can still change.

The practical BDN position is therefore two regimes, not three: the regulation 18 BDN that every commercial vessel issues and retains, and the FuelEU Maritime Article 9 fields added for vessels calling at EU and EEA ports.

Class society implementation: BDN review at IAPP renewal survey

The BDN and sample regime is verified by the classification society (acting as a recognised organisation on behalf of the flag administration) at the periodic IAPP renewal survey, which occurs at the 5-year IAPP cycle with intermediate annual surveys.

At the annual IAPP survey, the surveyor reviews:

• The on-board BDN file for the previous 12 months. The surveyor checks that a BDN exists for every recorded bunker delivery (cross-referenced against the Oil Record Book and the bunker tank logs).
• The BDN content of a sample of recent BDNs (typically 5-10), checking the ten Appendix V items and the sulphur declaration is consistent with the applicable cap.
• The on-board sample locker, checking that samples exist for every recorded bunker delivery within the previous 12 months, that the seals are intact, and that the chain-of-custody labels are complete.
• The bunker tank log and the Oil Record Book Part I entries for each delivery, cross-referenced against the BDN.

At the 5-year IAPP renewal survey, the surveyor performs the same review but with a longer look-back. The renewal survey also reviews the fuel-changeover procedure and the IAPP supplement entries for ECA transits.

A deficient BDN file (missing BDNs, incomplete fields, inconsistent sulphur declarations) results in a survey condition (a corrective action with a deadline) or, in serious cases, a withholding of the IAPP renewal, which prevents the vessel from trading until the deficiency is corrected. A deficient sample locker (missing samples, broken seals, incomplete chain-of-custody) is treated similarly.

The class society retains the BDN review records as part of its survey file, which is auditable by the flag administration and by the IACS as part of the recognised-organisation audit programme. The records are typically retained for at least 10 years after the survey.

PSC inspection focus: BDN vs IAPP vs sample test

Port state control (PSC) inspection of BDN compliance is governed by the Tokyo MoU, the Paris MoU, the USCG Port State Control Programme, and the various other regional MoUs (Indian Ocean MoU, Caribbean MoU, Mediterranean MoU). The inspection sequence at a typical PSC visit is:

1. Document review: The PSC officer reviews the IAPP supplement, the BDN file, and the Oil Record Book . The IAPP supplement records the fuel-changeover dates and the ECA transit log, which must be consistent with the BDN-recorded fuel grades.
2. BDN-IAPP cross-check: The officer verifies that the IAPP-recorded fuel grade for each ECA transit is consistent with the BDN-declared sulphur content of the fuel actually in the day tank during that transit.
3. Sample inspection: The officer inspects the on-board sample locker, checking seal integrity and chain-of-custody for the sample corresponding to the most recent bunker delivery and one or two earlier deliveries.
4. Sample test (selective): At the officer’s discretion, a sample is broken open (in the presence of the chief engineer) and a sub-sample is taken for flag-state laboratory analysis. The laboratory tests sulphur by ISO 8754. The Appendix VI procedure is applied to the result.
5. In-use or tank sample (where required): Where the on-board delivered sample is unavailable, broken-sealed, or the test result is contested, the officer may draw a fresh in-use sample (from the fuel supply line) or an onboard sample (from a tank) under Regulation 14.8, added by MEPC.324(75). A fresh tank sample is less probative than the manifold sample because the in-tank fuel has been mixed with previously bunkered fuel.

The verification chain for sulphur compliance is: commercial samples under the supply contract, the MARPOL delivered sample (at least 12 months), in-use or onboard samples drawn by the competent authority, and the laboratory result under Appendix VI. A consistent result across all four confirms compliance; a divergence at any stage is a Reg 14/Reg 18 deficiency.

The inspection procedure is set out in MEPC.321(74), the 2019 Guidelines for port State control under MARPOL Annex VI Chapter 3. The sequence, and how the file is reconciled when the documents disagree, is covered in FONAR and BDN sulphur compliance evidence .

PSC deficiency codes for BDN and sulphur findings

The Paris MoU deficiency code list of 1 July 2023 records MARPOL Annex VI fuel findings under group 146. Code 14604 is bunker delivery notes, 14607 quality of fuel oil, 14612 SOx records, 14615 the fuel changeover procedure, 14616 alternative arrangements (SOx) and 14617 sulphur content of fuel used. Whether a finding leads to detention is decided by the inspecting officer under the MoU procedures, not fixed by the code.

Bunker supply chain: Singapore, Fujairah, Rotterdam, Hong Kong, Houston

The global bunker market is concentrated at a small number of major bunkering hubs, ranked by 2024 delivery volume:

• Singapore: approximately 54 million metric tonnes delivered in 2024, the largest bunker port globally for the past two decades. Singapore is the principal bunkering hub for the Asia-Pacific trade and for vessels transiting between East Asia and the Indian Ocean. The Maritime and Port Authority of Singapore (MPA) operates a tightly regulated bunker licensing regime, with mandatory mass-flow meters on all supplier barges from 2017 (residual) and 2019 (distillate).
• Fujairah, UAE: approximately 35-40 million tonnes in 2024, the second-largest hub, serving the Indian Ocean trade and the Persian Gulf. Fujairah’s bunkering activity grew rapidly post-2010 with the build-out of storage capacity at the port and is a frequent calling point for tankers and bulk carriers between the Middle East and East Asia.
• Rotterdam (ARA range): approximately 8-10 million tonnes at Rotterdam alone, and 15-18 million tonnes for the broader Antwerp-Rotterdam-Amsterdam (ARA) range. Rotterdam is the principal bunkering hub for the European trade and for vessels transiting between the Atlantic and the North Sea.
• Hong Kong: approximately 5-6 million tonnes in 2024, serving the South China and Pearl River Delta trade. Hong Kong’s bunker market shrank in the 2020s as Singapore captured share, but remains a significant regional hub.
• Houston / US Gulf: approximately 6-8 million tonnes in 2024, serving the US Gulf petrochemical trade and transatlantic vessels. The US Gulf is the principal bunkering hub for the Americas trade.
• Other notable hubs: Algeciras (Mediterranean), Las Palmas (Atlantic island), Panama (canal transit), Busan (South Korea), Tanger Med (Mediterranean / Africa).

The supplier registration regime under Reg 18 applies in all of these jurisdictions, with the supplier-side audit performed by the bunker port’s flag administration. Singapore and Rotterdam are widely regarded as the most rigorous jurisdictions for supplier registration; some smaller bunkering ports in West Africa, the Caribbean and parts of South America have weaker supplier-side enforcement, and operators are advised to rely on third-party fuel-quality testing (VPS, FOBAS, Bureau Veritas Marine Fuel) for deliveries from these jurisdictions.

Charter-party and supply-contract allocation

On a time charter the charterer buys the fuel, and the clause decides who bears a BDN or sulphur problem. The BIMCO 2020 Marine Fuel Sulphur Content Clause for Time Charter Parties , published 10 December 2018, requires charterers to supply fuel that lets the vessel comply, warrant their suppliers and indemnify owners, with the vessel on hire; owners warrant the vessel complies. The BIMCO Bunker Quality and Liability Clause 2011 makes charterers liable for loss caused by unsuitable fuels, including off-loading them. The supply contract is usually BIMCO Bunker Terms 2018 , under which the master’s BDN signature acknowledges volume and delivery temperature only (clause 6(c)).

Bunker-quality dispute arbitration (IBIA + Court of Arbitration)

Bunker-quality disputes are typically resolved through one of three forums:

• LMAA (London Maritime Arbitrators Association) is the principal forum for bunker disputes governed by English law and is the default forum under the BIMCO clauses for many charter parties. LMAA bunker arbitrations typically run 12-24 months and produce binding awards enforceable internationally under the New York Convention.
• SCMA (Singapore Chamber of Maritime Arbitration) is the principal forum for bunker disputes arising in the Asia-Pacific bunker market, particularly Singapore-supplied fuel. SCMA bunker arbitrations are typically faster (8-18 months) and benefit from the close geographical link to the Singapore bunker market.
• IBIA-mediated commercial settlement: The International Bunker Industry Association (IBIA) operates a mediation service for bunker disputes at the commercial level (supplier-buyer), separate from the legal arbitration forums. IBIA mediation is non-binding but often produces settlements within 3-6 months at substantially lower cost than arbitration.

The principal technical evidence in a bunker-quality dispute is:

• The sellers’ retained samples (two kept for at least 45 days under BIMCO Bunker Terms 2018 clause 4(c)).
• The manifold sample (drawn at the receiving ship’s manifold, retained on board for 12 months under Reg 18).
• The commercial samples kept on board under the supply contract or charter party.
• The flag-state PSC sample (where a PSC inspection has occurred).
• The third-party laboratory test reports from VPS, FOBAS, Bureau Veritas Marine Fuel or equivalent.

Seal integrity decides the evidential value of every sample: Appendix VI paragraph 2.2.3 requires a broken-seal delivered sample to be rejected, and supply contracts apply the same logic to commercial samples.

The Bunker Delivery Note as a discrete-requirement instrument

Regulation 18 imposes a set of discrete documentation and retention requirements rather than a continuous limit function. There’s no single governing equation; there is a small set of fixed quantities, each of which a chief engineer or a port state control officer can check against the document and the sealed bottle on board. The retained sample is not less than 600 ml under MSC-MEPC.2/Circ.18, held until substantially consumed and for at least 12 months. The BDN itself is retained for three years on board, \(T_{\text{BDN,retention}} = 3\ \text{years}\). The declared sulphur must sit at or below the applicable cap, \(c_{\text{S,BDN}} \leq c_{\text{S,cap}}\), where \(c_{\text{S,cap}}\) is 0.50% m/m outside emission control areas (per Reg 14.1 ), and 0.10% m/m inside an emission control area under Reg 14.4.

These quantities are fixed by MARPOL and its guidelines, not derived from a model.

The flash-point and sulphur limits the BDN carries

The flash point under SOLAS Reg II-2/4.2 must be at least 60 degrees C by the Pensky-Martens closed-cup method (ISO 2719), \(T_{\text{flash,min}} = 60\ ^\circ\mathrm{C}\). That 60-degree line is the flammability-to-combustibility boundary in the IMO maritime classification: a liquid with closed-cup flash above 60 degrees C can’t form a flammable vapour-air mixture under ambient marine engineering conditions and may be handled in standard fuel-oil tanks without inerting. A 0.10% ULSFO with a 55-degree flash is a SOLAS deficiency irrespective of its Reg 14 compliance.

The sulphur cap recorded on the BDN is the document’s load-bearing field. The supplier’s declaration in item 10 certifies the sulphur content against the Reg 14.1 limit, the Reg 14.4 limit, or a purchaser-specified limit. When the delivered sample is tested, Appendix VI Part 1 compares the result with the Reg 14 limit itself, with no margin.

The MARPOL fuel-oil sample volume

MSC-MEPC.2/Circ.18 paragraph 7.3 sets the sample container at not less than 600 ml, filled to 90% plus or minus 5% and sealed. The circular serves both the MARPOL sulphur check and the SOLAS flashpoint check. Regulation 18.8.1 itself sets no volume; it sets the retention period, until the fuel is substantially consumed and for at least 12 months.

Worked example

A 12,000 TEU container ship bunkers 3,200 metric tonnes of VLSFO at Singapore on 5 May 2026 from a licensed supplier.

This is a hypothetical illustration. The supplier issues a BDN carrying the ten Appendix V items: the ship name and IMO number, the port (Singapore), the date delivery commenced (5 May 2026), the supplier’s name, address and telephone number, the product name (VLSFO), the quantity (3,200 t), the density at 15 degrees C, the sulphur content (0.46% m/m), the flashpoint, and the declaration with the Reg 14.1 box ticked. The supplier adds its own BDN reference number and the sample seal numbers.

A continuous-flow drip sample is drawn at the receiving ship’s manifold throughout the 4-hour delivery. The MARPOL delivered sample, in a container of not less than 600 ml, is sealed at the manifold by the supplier representative in the presence of the chief engineer on completion of bunkering, and the label is signed by both parties.

The BDN is filed in the chief engineer’s BDN binder under the May 2026 tab and is retained for 3 years (until 5 May 2029). The sample is retained in the sample locker for 12 months (until 5 May 2027).

A Tokyo MoU PSC inspection on 22 September 2026 (4.5 months post-delivery) reviews the BDN file, confirms the May 2026 BDN, inspects the on-board sample for the May 2026 delivery, confirms the seal is intact and the chain-of-custody label is complete, and decides not to draw the sample for testing (no other findings of concern). The inspection closes without deficiency.

In an alternative run, an October 2026 inspection at Yokohama draws the May 2026 sample for laboratory testing. The laboratory reports 0.48% m/m. Under Appendix VI Part 1, the delivered sample has no margin, and 0.48% is at or below the 0.50% limit, so the fuel has met the requirement. Had the result been 0.52%, it would not have met the requirement, whatever the BDN declared. The example shows the routine flow at a major bunkering hub: the BDN is the standing regulatory document, the sample is the contingent evidence that backs it if challenged.

Limitations

The Reg 18 regime is a documentary and evidential chain, not a direct measurement of what the engine burns, and several limitations follow from that.

The first limitation is the gap between BDN-declared quality and actual delivered quality. The BDN is the supplier’s certification; the MARPOL delivered sample, drawn at the receiving ship’s manifold under MSC-MEPC.2/Circ.18, is the check on it. The document is only as reliable as the sample it rests on.

The second limitation is the distinction between in-use, onboard, and delivered samples. The MARPOL manifold sample captures the fuel as delivered; the in-use sample (drawn from the engine fuel-supply system) and the onboard sample (drawn from a tank) capture fuel that has been blended with a residual heel of older fuel. Where the day tank is fed from a service tank holding mixed fuel, BDN attribution becomes uncertain, and a fresh in-tank sample drawn by a PSC officer is less probative than the manifold sample because the in-tank fuel is no longer a clean record of any single delivery.

The third limitation sits in the verification thresholds themselves. Appendix VI applies the 0.53% and 0.11% test margins to in-use and onboard samples only; the delivered sample is judged against the bare 0.50% or 0.10% limit. Applying the margin to the delivered sample understates how tight that boundary is, and treating the ISO 8217 grade as the regulatory benchmark compounds the error: a 3.0% RMG-380 is on-spec to the ISO grade yet non-compliant with the 0.50% cap.

The fourth limitation is enforcement variation. The fuel oil non-availability report (FONAR) under Regulation 18.2.4, in the format of appendix 1 to MEPC.320(74), lets a vessel record that compliant fuel couldn’t be obtained, but FONAR acceptance and follow-up differ markedly between flag and port states, and the FONAR doesn’t replace the BDN: the BDN must still be issued for the non-compliant fuel actually delivered.

A final limitation is that several figures in this article are estimates or ranges rather than fixed regulatory constants. The worked example is hypothetical, and the Appendix VI procedure names ISO 8754:2003 although ISO has since published ISO 8754:2025. Confirm the controlling figures against the current resolution text before relying on them in a dispute.

Regulatory basis

MARPOL Annex VI Regulation 18 and Appendix V, as revised by MEPC.328(76) and amended by MEPC.362(79) and MEPC.385(81); Appendix VI as replaced by MEPC.324(75); MEPC.286(71) for the declaration tick boxes; MSC-MEPC.2/Circ.18 of 11 July 2024 for sampling, which revoked MEPC.182(59); MEPC.320(74) for the FONAR format and MEPC.321(74) for port State control; and SOLAS regulation II-2/4.2.1.6 as amended by MSC.520(106).

Common operator errors

A handful of mistakes recur on board and in the supply chain. Operators treat the BDN as a commercial document only, when it is a regulatory document under Reg 18 whose obligation is independent of the supply contract. They equate the ISO 8217 grade with the Reg 14 cap, when a fuel on-spec to RMG-380 at 3.0% sulphur is non-compliant with the 0.50% global cap. They draw a batch sample at the start, middle, or end of a delivery instead of the continuous sample at the manifold that MSC-MEPC.2/Circ.18 describes. They dispose of the sample before 12 months or the BDN before 3 years, each a Reg 18 deficiency. They confuse the FONAR with the BDN, forgetting that a vessel filing a FONAR still receives a BDN for the non-compliant fuel actually delivered.They overlook the charter-party sulphur clause, which can shift the cost of a non-compliance between owner and charterer even where Reg 18 is satisfied. And they read the 3-year BDN retention as a ceiling rather than the floor it is.

Related Articles

• MARPOL Annex VI : parent annex (air pollution)
• MARPOL Annex VI Regulation 13: NOx Tier I, II, III : companion air-pollution regulation
• IMO 2020 sulphur cap : Reg 14 sulphur regime, the principal user of the BDN sulphur declaration
• MARPOL Convention : top-level treaty
• Baltic Sea SECA + NECA
• North Sea SECA + NECA
• FuelEU Maritime intensity formula breakdown : EU regional GHG-intensity regime, parallel BDN under Article 9
• IMO GFS methodology : the draft global GHG fuel intensity regime, and the Fuel Life Cycle Label that draft Chapter 5 would let travel with the Reg 18 BDN
• Per-fuel WTW: VLSFO and MGO
• Per-fuel WTW: HFO
• Per-fuel WTW: LNG Otto vs diesel
• MARPOL Annex I Regulation 17: Oil Record Book : companion documentation regulation