See unitsPollution prevention on ships: oil record book, garbage plan, SOPEP, ballast water and emission control areas
MARPOL Annex VI: sulphur limits, emission control areas and NOx
1The lesson in plain words
Use ≤0.50 % sulphur fuel worldwide and ≤0.10 % where an ECA limit applies, unless using an approved equivalent. Plan and log fuel changeovers.
Sulphur limits
MARPOL Annex VI covers air pollution. Since 1 January 2020 fuel oil used on board must contain at most 0.50 % sulphur by mass. Where an emission control area (ECA) sulphur limit is in effect, it is 0.10 %. An approved equivalent, such as an exhaust gas cleaning system (scrubber), may be used instead. Since 1 March 2020 a ship without one may not even carry fuel above 0.50 % for use.
The ECAs
Sulphur ECAs: Baltic Sea, North Sea, North American, US Caribbean, and the Mediterranean, where 0.10 % applies since 1 May 2025. The Canadian Arctic and Norwegian Sea ECAs entered into force on 1 March 2026; their 0.10 % limit starts on 1 March 2027. The North-East Atlantic ECA, adopted at MEPC 84 in 2026, enters into force on 1 September 2027, with 0.10 % from 1 September 2028.
NOx tiers
Diesel engines over 130 kW must meet a nitrogen oxides (NOx) tier set by the ship's construction date. Tier II applies worldwide to ships built from 2011. Tier III, about 80 % lower than Tier I, applies only inside a NOx ECA, for ships meeting that area's construction-date criteria: North American and US Caribbean from 2016, Baltic and North Sea from 2021. The Mediterranean ECA is for sulphur only.
New NOx dates
Canadian Arctic: ships constructed (normally keel-laid) on or after 1 January 2025. Norwegian Sea: building contract from 1 March 2026; if there is no contract, keel laid from 1 September 2026; or delivery from 1 March 2030, regardless of contract date. North-East Atlantic: contract from 1 January 2027; if none, keel laid from 1 July 2027; or delivery from 1 January 2031, regardless of contract date.
Changeover
If you use separate fuels for ECA compliance, follow your written changeover procedure and finish before entry. Fuel already at or below 0.10 % needs no changeover. If flushing takes 6 hours and you reach the boundary at 1800, start by 1200. Log date, time, position and compliant fuel volume in each tank at completion before entry and at commencement after exit.
Fuel papers
Keep each bunker delivery note for 3 years. Keep the sealed MARPOL sample until the fuel is substantially used, and for at least 12 months after delivery. If a supplier cannot give compliant fuel, report it to the flag and the port state before departure. EU rules, such as the EU ETS and FuelEU Maritime, add their own duties in EU trades.
2Key data
- Global sulphur limit
- 0.50 % m/m since 1 January 2020
- ECA sulphur limit
- 0.10 % m/m (since 1 January 2015 in the first ECAs)
- Mediterranean SOx ECA
- 0.10 % since 1 May 2025 (sulphur only)
- Canadian Arctic, Norwegian Sea
- In force 1 March 2026; 0.10 % from 1 March 2027
- North-East Atlantic ECA
- In force 1 Sept 2027; 0.10 % from 1 Sept 2028
- Bunker delivery note / sample
- BDN 3 years; sample ≥12 months and until fuel substantially used
3Key points
- 1
0.50 % globally; 0.10 % where the ECA limit applies, unless using an approved equivalent.
- 2
Mediterranean SOx ECA since 1 May 2025.
- 3
Canadian Arctic and Norwegian Sea: 0.10 % from 1 March 2027.
- 4
Tier III NOx applies only in NOx ECAs, for ships meeting their construction-date criteria.
- 5
Log changeovers: date, time, position and compliant fuel volume in each tank.
4Frequent mistakes
Wrong: Start the fuel changeover as you cross the ECA boundary.
Right: Finish it before you enter. Plan back from the boundary using the flushing time in your procedure.
Wrong: Every ship in a NOx ECA must have Tier III engines.
Right: Tier III applies in a NOx ECA to ships meeting that area's construction-date criteria. Older ships keep their Tier I or II engines.
5Practice case & exam keys
In March 2027 your ship, built in 2015 and without a scrubber, will sail from Halifax to Iqaluit in the Canadian Arctic. The chief engineer says the new ECA is not in force for fuel until 2028. Is he right?
Show the answer
No. The Canadian Arctic ECA entered into force on 1 March 2026, and the 0.10 % sulphur limit applies from 1 March 2027. You need fuel containing no more than 0.10 % sulphur inside the ECA. If changing fuels, finish and log the changeover before entry. Halifax lies in the North American ECA, so you may already be burning compliant fuel. Tier III does not apply, since she was built before 2025.
Exam keys
- 0.50 % since 2020; 0.10 % where the ECA limit is effective; approved equivalents allowed.
- Sulphur ECAs: Baltic, North Sea, North American, US Caribbean, Mediterranean (1 May 2025).
- Canadian Arctic and Norwegian Sea: in force 1 Mar 2026, 0.10 % from 1 Mar 2027; NE Atlantic 2027/2028.
- Tier III only in NOx ECAs, for ships meeting construction-date criteria; log changeovers; BDN 3 years.
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