MARPOL and the other environment conventions
1The lesson in plain words
MARPOL has six annexes, one for each kind of pollution. Ballast water, antifouling paint and ship recycling each have their own convention.
MARPOL
The International Convention for the Prevention of Pollution from Ships (MARPOL) dates from 1973 and was combined with its 1978 Protocol. It entered into force on 2 October 1983. Its six annexes cover oil (I), noxious liquid substances in bulk (harmful liquid cargoes carried in tanks) (II), harmful substances in packaged form (III), sewage (IV), garbage (V) and air pollution (VI). States joining MARPOL accept I and II. They may accept III–V separately; VI requires joining the 1997 Protocol.
How MARPOL works
Check the applicable annex for equipment, survey, certificate and record requirements. Examples include the International Oil Pollution Prevention (IOPP) Certificate, International Air Pollution Prevention (IAPP) Certificate and Oil Record Book. Not every annex requires both a certificate and a record book; Annexes III and V have no international MARPOL certificate. Detailed pollution controls and record-keeping are covered in Ocean: pollution prevention.
Greenhouse gas
Annex VI also covers energy efficiency. In April 2025 the MEPC approved a draft IMO Net-Zero Framework: a global fuel standard with a carbon price. In October 2025 an extraordinary session voted to adjourn its adoption for one year. At the time of writing, it has not been adopted. Watch for the outcome, because MARPOL amendments can apply about 16 months after adoption.
Ballast water and antifouling
For ships subject to the Ballast Water Management (BWM) Convention 2004 D-2 standard, the phase-in ended on 8 September 2024. D-2 limits living organisms discharged in ballast water, usually met through approved treatment. The Anti-fouling Systems (AFS) Convention 2001 bans tributyltin (TBT) biocides in hull coatings. New application of cybutryne coatings has been banned since 1 January 2023; existing coatings have removal or sealing deadlines.
Ship recycling
The Hong Kong Convention on ship recycling entered into force on 26 June 2025. Covered new ships must have an Inventory of Hazardous Materials (IHM), a list of hazardous materials on board. Covered existing ships of 500 GT and above need a certified IHM by 26 June 2030, or before recycling if that is sooner. Ships may only be recycled at authorised yards.
2Key data
- MARPOL
- In force 2 Oct 1983; Annexes I and II compulsory
- Six annexes
- Oil, noxious liquids, packaged, sewage, garbage, air
- BWM D-2
- Phase-in ended 8 Sept 2024 for ships subject to D-2
- AFS bans
- TBT banned; new cybutryne applications banned from 1 Jan 2023
- Hong Kong Convention
- In force 26 June 2025; covered existing ships: IHM by 26 June 2030
- Net-Zero Framework
- Approved Apr 2025; adoption adjourned Oct 2025
3Key points
- 1
MARPOL has six annexes; Annexes I (oil) and II (noxious liquids) are compulsory.
- 2
MARPOL certificates and records depend on the annex; not every annex requires both.
- 3
For ships subject to D-2, the BWM phase-in ended on 8 September 2024.
- 4
Covered new ships need an IHM; covered existing ships need one by 26 June 2030, or before recycling if sooner.
4Frequent mistakes
Wrong: The IMO Net-Zero Framework already applies to ships.
Right: Its adoption was adjourned in October 2025, and it is not yet adopted. Follow your company's updates.
Wrong: Ballast water exchange at sea is still enough under the BWM Convention.
Right: Since 8 September 2024 ships subject to D-2 must meet limits on living organisms discharged, usually with an approved treatment system.
5Practice case & exam keys
Under the Hong Kong Convention alone, your covered 15-year-old bulk carrier is inspected in late 2026. The chief engineer says: "The Inventory of Hazardous Materials is only for ships going to the breakers." Is he right, and is the IHM already overdue?
Show the answer
No. An IHM identifies hazardous materials throughout the ship’s working life, not only before recycling. Under the Hong Kong Convention alone, a covered existing ship needs a certified IHM by 26 June 2030, or before recycling if sooner. In late 2026, that transition period is still running. Do not claim it is overdue solely because the Convention entered into force in 2025.
Exam keys
- MARPOL 73/78: six annexes; I and II compulsory; IOPP, IAPP certificates.
- BWM 2004: in force 2017; D-2 phase-in ended 8 September 2024 for ships subject to D-2.
- AFS 2001: TBT banned; new cybutryne applications banned since 1 January 2023.
- Hong Kong Convention in force 26 June 2025; covered existing ships: IHM by 26 June 2030, or earlier recycling.
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