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Emission control areas

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An emission control area is an area of sea where the fuel a ship may burn has a stricter limit than everywhere else. It does not change the route, the cargo or the ship's speed. What it changes is which fuel grade the ship burns from which tank. Because the two grades have different prices, a voyage that spends a week inside an area has a higher fuel bill than a voyage of the same length outside it.

What the limit actually is

Under MARPOL Annex VI, the sulphur in fuel oil used on board is limited to 0.50% by mass worldwide. Inside a designated emission control area the limit is 0.10%. That has been the limit in every established area since 1 January 2015, and it is what the trade means when it says a voyage is “in the ECA”.

A ship can meet the limit in two ways. The usual way is to burn a compliant fuel: a distillate, usually low sulphur marine gas oil, instead of the heavier residual fuel the main engine burns at sea. The other way is an approved equivalent, which in practice means an exhaust gas cleaning system (a scrubber). It lets the ship keep burning high sulphur fuel and clean the exhaust instead. Which method a particular ship uses is a fact about that ship, and it decides whether the area costs it anything at all.

Where they are

There are ten areas, and they are not all of the same kind. Three are enclosed or partly enclosed seas whose boundaries are written as lines of latitude and longitude. Four are drawn at a fixed distance from a North American coastline. The last three were designated recently and do not cost anything yet, which is the point people most often get wrong.

AreaWhat it controlsThe date that matters
Baltic SeaSulphur, and Tier III nitrogen oxides for ships whose keels were laid on or after 1 January 2021In force since 2006, at 0.10% since 2015
North Sea and English ChannelSulphur, and Tier III for keels laid from 1 January 2021In force since 2007, at 0.10% since 2015
North American, Atlantic and Gulf of MexicoSulphur, and Tier III for keels laid from 1 January 20161 August 2012
North American, PacificAs above1 August 2012
North American, HawaiiAs above1 August 2012
United States Caribbean SeaAs above1 January 2014
Mediterranean SeaSulphur and particulate matter only. There is no nitrogen oxide requirement1 May 2025
Canadian ArcticSulphur and Tier IIIIn force 1 March 2026. Fuel requirement from 1 March 2027
Norwegian SeaSulphur and Tier IIIIn force 1 March 2026. Fuel requirement from 1 March 2027
North-East AtlanticSulphur and Tier IIIIn force 1 September 2027. Fuel requirement from 1 September 2028

A designated area is not yet a cost

Look again at the last three rows, because this is where estimates go wrong in both directions.

The Canadian Arctic and the Norwegian Sea became emission control areas on 1 March 2026, but the 0.10% fuel requirement there does not start until a year later. An estimate written today for a voyage next month that charges distillate for the Norwegian Sea includes a cost that does not exist, and the broker who wrote it will lose the cargo to someone who did not.

The North-East Atlantic is the larger area, and there the mistake is the opposite one. It covers the waters off Ireland, the United Kingdom, France, Spain, Portugal, the Faroes, Iceland and Greenland, with the Azores, Madeira and the Canaries included separately. That is most of the Atlantic side of the European trades. The area comes into force on 1 September 2027, and the fuel requirement follows on 1 September 2028. A voyage quoted now for 2028 is being priced as if that water had no limit, and it will have one.

So each area has a date, and an estimate must be priced against the date rather than against the map. The two mistakes sit next to each other in the table, but only one of them is easy to see.

Designated, not yet costly

Three of the ten areas exist today but cost nothing today. What prices a voyage is the date the fuel requirement starts, not the date the area was designated. In all three the gap between the two dates is a year, and in each of those years there are fixtures someone has to quote.

The boundaries, and which of them are real lines

Some of these boundaries are exact and some are approximate, and you should know which kind you are dealing with.

The enclosed seas are defined by lines. The Baltic ends at the latitude of the Skaw, 57°44.8’N, drawn across the entrance in the Skagerrak; everything south and east of it is Baltic. The North Sea area ends at 62°N in the north and at 4°W in the west, and its corner in the Channel is at 48°30’N and 5°W. The Mediterranean ends at 5°36’W in the Strait of Gibraltar and at the 41st parallel in the Turkish straits. These are the regulation's own coordinates, and they need no interpretation.

The North American and United States Caribbean areas work differently. Each is drawn 200 nautical miles out from a baseline, which is a curve, and the regulation defines it with about a hundred and thirty published coordinates. Any approximate drawing of that shape is only approximate, so a route measured against it is accurate to tens of miles, not to the mile.

Two practical results follow. The Irish Sea and the Celtic Sea are outside the North Sea area, because the regulation's western limit runs down 5°W to the coast of Cornwall instead of around Ireland. They stay outside until the North-East Atlantic area starts, and then they are inside. And the Black Sea is not an emission control area at all, while the Sea of Marmara south of 41°N is, so a ship coming down from Novorossiysk enters an area partway through the Turkish straits.

Nitrogen oxides are a different control on a different thing

The sulphur limit is about the fuel in the tank, so it applies to every ship that enters the area. Tier III nitrogen oxide control is about the engine, and it applies to a ship according to when its keel was laid or its building contract was signed. That makes it a fact about the ship, not about the voyage. An older ship is not affected at all, while a newer one had to be built to meet it. It does not change what fuel this voyage burns.

The dates differ by area and are not obvious. North American waters cover keels laid from 1 January 2016, the Baltic and North Sea cover keels from 1 January 2021, and the Canadian Arctic covers keels from 1 January 2025. The Mediterranean has no nitrogen oxide requirement at all. For chartering, the practical point is simple: sulphur is a cost on this voyage, while nitrogen oxide is a question about how a particular ship was built, and the answer is on its certificates rather than in a table.

What it does to an estimate

The fuel switch affects one line of the estimate, not the whole fuel bill. At sea, a ship burns the heavy grade in its main engine and a distillate in its auxiliary engines and boiler. Inside an emission control area, only the main engine changes grade, because the auxiliary engines were already burning distillate. So the miles inside the area move part of the heavy fuel quantity to the distillate price. An estimate that reprices the whole day counts the auxiliary fuel twice.

It helps to know which trades are affected before you open the estimate. Since May 2025 the whole Mediterranean has been an area, so a ship coming up from Suez burns distillate for every mile from the canal to Gibraltar. That one change put a long stretch of controlled water in the middle of the trades from the Gulf and Asia to north-west Europe, where before there was none between the Red Sea and the Channel.

Who pays depends on the charter. Under a voyage charter the owner buys the fuel, so the area is the owner's cost and belongs in the freight. Under a time charter the charterer buys the fuel, so the cost is the charterer's. What the owner must provide is a ship that can really burn the compliant grade, and the certificates to prove it.

Steaming round one, and when that is a fantasy

Because the areas are geographical, the obvious question is whether a ship can stay out of one. Sometimes it can. The North American area extends out to sea, so a ship sailing between two United States ports may find that heading further offshore and coming back in saves more distillate than the extra distance costs. That is a real trade-off, and it is worth working out both ways.

Often, though, it cannot. What decides this is how deep inside the area the ship is, not how far away the nearest boundary is. The North Sea area is hundreds of miles across in every direction that matters, so a ship at Rotterdam is nowhere near a useful edge of it. A ship loading in the Baltic has only one way out, past the Skaw, several hundred miles away, and taking that route is not a way around the area; it is the voyage itself. The Mediterranean works the same way. Asking whether to avoid an area when your loading berth is inside it makes no sense, and software that gives a number for it is not measuring anything real about the route.

What none of this is

Everything above is a planning description of where the money goes. It is not a compliance tool. Boundaries change when the regulation is amended, and several of these areas have exclusions and exceptions that a simple rectangle or traced outline cannot capture. The reporting and record-keeping duties that come with a fuel changeover are a matter for the ship, not for an estimate. Check the boundary, the requirement and the paperwork against the current regulation and the flag state before anyone relies on them. An estimate needs to know how many miles are inside an area and what the fuel grade costs, and that question is deliberately narrower than compliance.

References

Bunkers and fuel gradesTwo fuel grades, sometimes three, each with its own price. The largest number on a voyage estimate is also the one nobody guarantees. Time charter equivalentFreight per tonne cannot be compared with hire per day until you divide it by the voyage. This is the arithmetic that does it. Voyage charter vs time charterHow the two main charter types split the risk, what each side pays for, and which terms exist in only one of them.

Neptune Atlas

Neptune Atlas measures how many miles of a drawn route fall inside each area and adds the total to the estimate as days of distillate, so the fuel switch is priced rather than typed in by hand. The boundaries are planning approximations of the published areas, and each one records how it was drawn. The product says so on every answer instead of presenting them as the regulation. Every paid plan starts with 7 free days. A card is needed to start them, and cancelling before they end costs nothing.

Try 7 days free Free sea distance calculator, with the miles inside each ECA What each plan includes