MARPOL Annex V Reg 6: discharge within special areas

What Regulation 6 is, and where it sits in the revised Annex V

Regulation 6 of MARPOL Annex V carries the title “Discharge of garbage within special areas.” It is one of ten regulations in the revised annex adopted by Resolution MEPC.201(62) at the 62nd session of the Marine Environment Protection Committee on 15 July 2011, in force from 1 January 2013. The revised text replaced the permission-based logic of the 1988 annex with a prohibition-based logic: Regulation 3 prohibits discharge of all garbage into the sea except as the annex expressly allows, and the express allowances live in Regulations 4, 5, and 6.

The numbering matters, because it has been mislabelled before. In the consolidated revised Annex V the layout is fixed: Regulation 1 (definitions), Regulation 2 (application), Regulation 3 (general prohibition on discharge of garbage into the sea), Regulation 4 (discharge of garbage outside special areas), Regulation 5 (special requirements for discharge from fixed and floating platforms), Regulation 6 (discharge of garbage within special areas), Regulation 7 (exceptions), Regulation 8 (reception facilities), Regulation 9 (port State control on operational requirements), and Regulation 10 (placards, garbage management plans, and garbage record-keeping). Regulation 6 is the special-area rule and the topic of this article; the outside-area rule is Regulation 4.

The structure of Regulation 6 is short and dense. Paragraph 1 sets out the permitted discharges inside a special area and the conditions on each. Paragraph 1.1 governs food waste. Paragraph 1.2 governs cargo residues, cleaning agents, and additives contained in hold-washing water that are not HME. Paragraph 2 imports the Polar Code restrictions for the Arctic, where they apply. Paragraph 3 deals with the situation where garbage is mixed with, or contaminated by, other substances prohibited from discharge or having different discharge requirements, and applies the more stringent rule. Everything not expressly permitted by paragraph 1 is prohibited by the parent Regulation 3, so the master reads Regulation 6 as a closed list of what may go over the side, not an open one.

A practitioner who needs the rule applied in one line works it this way: inside a special area, retain everything for shore reception or approved incineration, and discharge to sea only comminuted food waste at 12 nm or more, or non-HME cargo residue at 12 nm or more where the narrow triple condition is met. The rest of this article unpacks each clause, the eight areas and their dates, the chemistry that drives the HME gate, and the voyage planning that the regime forces on the master.

Why a special area is stricter than the open sea

A MARPOL special area is a sea area where, in the words of the convention, “for technical reasons relating to its oceanographical and ecological condition and to the particular character of its traffic, the adoption of special mandatory methods for the prevention of sea pollution is required.” The Annex V special areas are semi-enclosed or enclosed seas with restricted water exchange, concentrated shipping, and high ecological value: the Mediterranean basin flushes through the Strait of Gibraltar over an estimated turnover measured in decades, the Baltic over even longer, and a discarded item does not disperse the way it would on an open-ocean track.

The stricter regime follows from that hydrography. Outside special areas, Regulation 4 lets comminuted food waste go to sea at 3 nm and non-comminuted food waste and non-HME cargo residue at 12 nm, because the open ocean disperses and breaks down organic matter along a moving ship’s wake. Inside a special area, Regulation 6 raises the food-waste distance to 12 nm, deletes the non-comminuted food-waste pathway entirely, and clamps cargo-residue discharge to a triple condition that, in practice, almost never holds. The difference between the two regulations is the difference between a coastal sea that cannot flush a contaminant and an ocean that can.

The special-area concept is shared across MARPOL annexes, but each annex designates its own list. The Annex V garbage special areas are not identical to the Annex I oil special areas or the Annex VI emission control areas, and they are distinct again from the air-emission control zones such as the Baltic SECA and NECA, the North Sea SECA and NECA, and the Mediterranean SECA effective 2025. A vessel may be inside an Annex VI emission control area and outside the Annex V garbage special area at the same position, or the reverse. The boundaries are defined by coordinates in each annex, not by the commercial name of the sea, so the passage plan must check the Annex V coordinates specifically.

The eight Annex V special areas and their effective dates

MARPOL Annex V designates eight special areas, more than any other annex. Designation is not the same as taking effect. Under Regulation 6 read with the special-area machinery, a special area’s discharge restrictions take operational effect only after the parties whose coastlines border it have notified the IMO that adequate reception facilities are in place, and after the IMO has set an effective date. That two-step design avoids forbidding sea discharge in waters where no shore facility exists to take the waste. It has produced multi-decade gaps between designation and effect for some areas.

The verified position, drawn from the IMO special-areas table and the relevant MEPC resolutions, is as follows.

Baltic Sea. In effect from 1 October 1989, the earliest of the eight. The area covers the Baltic proper, the Gulfs of Bothnia, Finland, and Riga, and the Kattegat to a line drawn through the Skaw at the entrance. Reception-facility provisioning is the strongest of any area, supported by the HELCOM Convention 1992 and the regional no-special-fee arrangement that bundles garbage reception into port dues. The Baltic is the operational benchmark for an Annex V special area that works as designed.

North Sea. In effect from 18 February 1991. The area runs from the Skagerrak south through the North Sea proper and into the English Channel and its approaches, bounded to the west and south by lines defined in the annex. Reception-facility coverage at Rotterdam, Antwerp, Hamburg, Bremerhaven, and the UK and Norwegian ports is dense, and operational quality is high.

Antarctic area. In effect from 17 March 1992. The area is all sea south of latitude 60 degrees S. It is the strictest case under Regulation 6: the only sea discharge of any garbage permitted is comminuted food waste at 12 nm from the nearest land or ice shelf, and even that is constrained further by the Polar Code. The Antarctic special area and Polar Code regime and the broader Polar Code require many ships to retain food waste on board for discharge outside the Antarctic Treaty area rather than rely on the 12-nm pathway.

Gulfs area. In effect from 1 August 2008. The area covers the sea north-west of the rhumb line between Ras al Hadd and Ras al Fasteh, taking in the Persian or Arabian Gulf and the Gulf of Oman within that bound. The effective date is later than the early designation because riparian reception-facility provisioning lagged the regional shipping volume for decades.

Mediterranean Sea. In effect from 1 May 2009. The area is the Mediterranean proper including its gulfs and seas, bounded to the west by the meridian through Cape Spartel at the entrance to the Strait of Gibraltar and to the east by the entrance to the Dardanelles. Reception quality is uneven across the basin, strong at the Western European and large Italian, Spanish, and French ports and variable at some Eastern Mediterranean and North African ports, but the discharge regime is in force throughout.

Wider Caribbean Region. In effect from 1 May 2011, after a long delay from the 1991 designation. The area takes in the Gulf of Mexico, the Caribbean Sea proper, and the adjacent waters bounded by lines defined in the annex. The Wider Caribbean is the only special area where the Regulation 6 cargo-residue pathway has any routine practical relevance, because intra-regional bulk trades can satisfy the both-ports-inside-the-area condition that the open-ocean trades cannot.

Red Sea. In effect from 1 January 2025. This is the change a 2026 reader must get right. The Red Sea was designated in the 1973 text but remained not in effect for over four decades for the reception-facility reason. Resolution MEPC.382(80), adopted at MEPC 80 in July 2023, set 1 January 2025 as the date the Annex V Red Sea discharge restrictions take effect. The Annex V Red Sea area is defined as the Red Sea proper including the Gulfs of Suez and Aqaba, bounded to the south by the rhumb line between Ras si Ane (12 deg 28.5’ N, 043 deg 19.6’ E) and Husn Murad (12 deg 40.4’ N, 043 deg 30.2’ E). From 1 January 2025 a ship in the Red Sea applies Regulation 6, not Regulation 4.

Black Sea. Designated in the 1973 text, not yet in effect as of 2026. The required reception-facility notifications from the riparian parties have not triggered an effective date. A ship in the Black Sea is bound, in formal legal terms, by the Regulation 4 outside-area regime, not Regulation 6, even though many flag-state policies and operators apply the special-area regime voluntarily.

The two-step machinery is the source of a recurring compliance error: applying the special-area rule to the Black Sea on the strength of its designation. The legal position is that until an effective date is set, the outside-area Regulation 4 distances govern. The opposite error, applying the old “not in effect” status to the Red Sea after 1 January 2025, is now the more common one, because the IMO summary table that many onboard references copied was published before MEPC.382(80) took effect and still carries the asterisk.

Food waste inside a special area: comminuted, 25 mm, 12 nm, en-route, 4 knots

Regulation 6.1.1 permits the discharge of food waste inside a special area only when all of the following are satisfied at once. The food waste must be comminuted or ground so that it can pass through a screen with openings no greater than 25 mm. It must be discharged at a distance of not less than 12 nautical miles from the nearest land or, in the Antarctic area, the nearest land or ice shelf. The ship must be en-route, meaning under way on a voyage, and proceeding at not less than 4 knots. And the food waste must not be contaminated by any other garbage type with a different discharge requirement, or the more stringent rule applies under Regulation 6.3.

Each element is a hard gate, not a guideline. The 25 mm screen is a physical test: a galley macerator or comminutor reduces food waste to a slurry that passes a 25 mm mesh, and food waste that has not gone through that process cannot be discharged inside a special area at all. The drafters paired comminution with the food-waste permission deliberately, so that non-comminuted food waste has no special-area discharge pathway. A ship without a working macerator retains all food waste inside a special area.

The 12-nm distance is measured to the nearest land in any direction, which the annex defines to include offshore islands and, in the Antarctic, ice shelves. A discharge 13 nm from the mainland but 8 nm from an offshore islet fails the test, because the islet is land. The operational reference is the nearest-land contour displayed on the ECDIS, checked against the special-area boundary coordinates rather than against the geographic name of the sea.

The 4-knot and en-route conditions encode the dispersion-by-motion principle. A ship making 4 knots over a discharge of comminuted food waste at, say, 0.5 to 2 cubic meters per nautical mile of track spreads the slurry over kilometers of wake, where dilution and aerobic breakdown begin before any following ship reaches the same water. A ship at anchor or drifting cannot satisfy the condition regardless of how far it sits from land; the discharge would be a localized point release that defeats the dispersion logic. Most flag states read the 4-knot speed as speed over the ground, so a ship making 4 knots through the water against an equal adverse current is stationary over the ground and does not meet the spirit of the test, though the annex text states the speed without expressly qualifying SOG against STW.

Compare this with the Regulation 4 outside-area food-waste rule: outside a special area, comminuted food waste goes to sea at 3 nm and non-comminuted at 12 nm, both en-route at 4 knots. Inside, the comminuted distance quadruples to 12 nm and the non-comminuted pathway disappears. The food-waste rule is the single permission the master uses most inside a special area, and the 3-nm-to-12-nm jump is the number to remember when a ship crosses a special-area boundary mid-voyage.

Cargo residues inside a special area: the triple condition and the 12-nm standoff

Regulation 6.1.2 is the cargo-residue clause, and it is the most conditioned permission in Annex V. Inside a special area, cargo residues, cleaning agents, or additives contained in hold-washing water may be discharged to sea only when all three of the following hold, on top of the en-route and distance conditions.

First, the cargo residues and any cleaning agents or additives in the hold-washing water must not be classified as Harmful to the Marine Environment (HME). An HME residue is barred from any special area without exception, mixed or unmixed. Second, both the port of departure and the next port of destination must be inside the special area, and the ship must not transit outside the special area between those two ports. Third, no adequate reception facility for the residue must be available at the port of departure or the next port of destination, having regard to guidelines developed by the IMO.

Only when all three conditions are met may the discharge occur, and then only as far as practicable from the nearest land and not less than 12 nautical miles from the nearest land, with the ship en-route. The discharge must follow emptying of the hold by ordinary cargo-handling means; “cargo residue” is the material that cannot be recovered through normal unloading, not recoverable cargo that the master finds convenient to wash overboard.

The triple condition is restrictive by design, and it rarely holds. The both-ports-inside requirement excludes the typical bulk voyage, which loads inside a special area and discharges across an ocean, or the reverse. The no-adequate-facility requirement assumes a documented gap in reception provisioning at both ports, which is the exception in the developed regions where most special areas lie. In practice, Regulation 6.1.2 has routine relevance mainly in the Wider Caribbean Region, where intra-regional dry-bulk trades can satisfy both-ports-inside and where reception-facility provisioning has historically been uneven.

The clause also brings cleaning agents and additives into the chemistry test. Cleaning agents or additives in hold-washing water, and separately those in deck and external-surface washing water, may be discharged only when they are not HME. A manufacturer’s declaration that a cleaning product is not HME is the supporting document, kept in the ship’s records, and the cleaning regime on a bulk carrier or chemical-residue wash is planned around products that carry that declaration. A cleaning agent classified HME cannot be discharged inside a special area, mixed or not, and the wash water carrying it must be retained.

The cargo-residue pathway interacts directly with the IMSBC Code declaration. The HME classification of a solid bulk cargo is made by the shipper before loading and stated in the cargo declaration under the IMSBC Code’s information requirements; the master is entitled to rely on it absent evident error or fraud. That declaration is what tells the master whether Regulation 6.1.2 is even potentially open for the residue, before the both-ports and no-facility tests are reached.

The HME chemistry gate, in brief

The Harmful to the Marine Environment classification is the chemistry test that splits cargo residues into Category K (HME) and Category J (not HME), and it is the gate that decides whether Regulation 6.1.2 can apply at all. The criteria were added to Annex V by Resolution MEPC.277(70), adopted on 28 October 2016 at MEPC 70 and in force from 1 March 2018, and they tie the maritime rule to the UN Globally Harmonized System (GHS) of classification and labelling.

A solid bulk cargo is HME if it meets any of a set of GHS-based criteria: acute aquatic toxicity Category 1; chronic aquatic toxicity Category 1 or 2; carcinogenicity Category 1A or 1B together with a particle form that does not chemically alter on dissolution; mutagenicity Category 1A or 1B; reproductive toxicity Category 1A or 1B; specific target organ toxicity after repeated exposure Category 1; or classification as containing or consisting of synthetic polymers, rubber, plastics, or plastic feedstock pellets, regardless of acute toxicity, on the precautionary plastics-pollution ground. The plastics criterion is why plastic feedstock pellets carried as bulk cargo are HME by definition and may never be discharged in any sea area.

The full treatment of the H/J split, the GHS criteria, the IMSBC declaration mechanics, and the e-waste category sits in the companion article on HME cargo residues and e-waste. For Regulation 6 the operative point is binary: an HME residue is barred from every special area without exception, and a non-HME residue is potentially dischargeable inside a special area only where the both-ports and no-facility conditions are also met. The chemistry test is upstream of the geography test.

What is prohibited inside a special area

Everything not expressly permitted by Regulation 6.1 is prohibited by the parent Regulation 3, so the prohibited list inside a special area is long. Plastics of every kind, including synthetic ropes, synthetic fishing nets, plastic bags, and any plastic-containing item, are barred absolutely, the same as everywhere else under Annex V since 31 December 1988. Domestic wastes such as paper, rags, glass, metal, bottles, and crockery are barred. Cooking oil is barred. Operational wastes, including cleaning rags, deck-cleaning solids, abrasive-blasting media, and paint scrapings, are barred. E-waste is barred. Animal carcasses, which outside a special area may be discharged as far from land as possible, are barred from discharge inside a special area. Incinerator ash and clinker are barred.

The contrast with the outside-area regime is sharp on three categories. Outside a special area, Regulation 4 permits non-comminuted food waste at 12 nm, heavy-metal-free incinerator ash at more than 12 nm, and animal carcasses at a great distance from land. Inside a special area, all three of those pathways close: non-comminuted food waste, incinerator ash, and animal carcasses must be retained for shore reception or, where the equipment exists and the residue qualifies elsewhere, for approved on-board incineration with the ash retained.

Regulation 6.3 closes the mixing loophole. Where garbage is mixed with, or contaminated by, other substances that are prohibited from discharge or that have different discharge requirements, the more stringent requirement applies to the whole mixture. A bag of comminuted food waste that has picked up plastic packaging is no longer dischargeable food waste; it is a mixture that includes a prohibited category, and the whole bag is retained. The mixing rule is why segregation discipline on board is the precondition for any lawful special-area discharge: the moment food waste touches plastic, the food-waste permission is lost.

The practical default inside a special area is therefore retention. The deck and engine departments segregate by category under the ship’s garbage management plan, comminute food waste through the galley macerator where one is fitted and discharge it under the 12-nm pathway when the ship is en-route at 4 knots clear of land, and retain everything else for the next reception facility outside the area or for an in-area facility where one exists. The retention volume, the storage layout, and the segregation containers are the operational consequence of Regulation 6, and they are what the master plans around before the ship enters the area.

Regulation 7 exceptions that survive inside a special area

Regulation 6 is overridden by Regulation 7, the exceptions clause, in the same narrow circumstances that override Regulation 4. Inside a special area, as outside it, the discharge prohibitions do not apply to a discharge of garbage from a ship necessary for securing the safety of the ship and those on board, or for saving life at sea. They do not apply to the accidental loss of garbage resulting from damage to the ship or its equipment, provided all reasonable precautions were taken before and after the damage to prevent or minimize the loss. And they do not apply to the accidental loss of fishing gear, provided all reasonable precautions were taken to prevent the loss, or to the discharge of fishing gear from a ship for the protection of the marine environment or the safety of that ship or its crew.

The exceptions are defenses in fact, not operating permissions. A master invoking the casualty exception inside a special area must support it with deck-log entries of the event, an entry in the garbage record book describing it, photographs where practicable, and a report to the flag-state Administration. The threshold is high, and the exception does not authorize routine operational discharge that the master finds inconvenient, discharge of accumulated garbage that has become awkward to store, or discharge to avoid a reception-facility fee. Inside a special area the practical reach of Regulation 7 is narrow, because the safety and casualty triggers are rare and the routine garbage stream stays subject to the full Regulation 6 prohibition.

There is no special-area exception for hardship in finding a reception facility. If a port refuses a category, charges a high fee, or lacks capacity, the answer under the regime is retention on board for a later port, not invocation of Regulation 7. The exceptions clause is about safety and accident, not commercial or logistical difficulty.

Voyage planning around a special area

The special-area regime forces a planning step that the outside-area regime does not. Before a ship enters an Annex V special area, the master and chief mate plan the garbage and cargo-residue handling for the time inside the area: which categories can still be discharged, which must be retained, how much retention volume the voyage will generate, and where the next reception facility outside the area or inside it sits in the schedule. The plan is recorded in the ship’s garbage management plan and executed through the garbage record book entries that follow each operation.

The retention calculation drives the storage layout. A passenger ship transiting the Mediterranean for several days generates food waste, domestic waste, plastics, and operational waste at a rate set by complement and duration; only the comminuted food-waste fraction can go to sea at 12 nm, and everything else accumulates until the next reception facility. The chief mate estimates the accumulation against the available garbage-store volume and the compaction and incineration capacity, and books reception facility slots at the in-area or post-area ports accordingly. A ship that enters a special area without the retention capacity to last to the next facility has planned badly, and the consequence is either an unlawful discharge or a schedule disruption to land the waste.

Cargo-residue planning is the harder case. The chief mate determines from the IMSBC Code declaration whether the loaded cargo’s residue is HME, and therefore barred from any special-area discharge, or non-HME and potentially dischargeable under Regulation 6.1.2. If the residue is non-HME and both the load and discharge ports lie inside the special area with no adequate reception facility, the narrow in-area discharge pathway opens; otherwise the residue is retained for shore reception. The cargo-hold cleaning plan written before loading states the residue category, the HME determination, the planned discharge route, and the garbage record book Part II entries the chief mate will make. That plan is what links the loaded cargo, the special-area geography, and the lawful disposal route into a single auditable chain.

The plan must also handle the boundary crossing. Garbage generated outside a special area cannot be discharged retroactively under the outside-area Regulation 4 distances once the ship has entered the area; the governing regime is the one applicable at the time and position of discharge, recorded in the garbage record book. A ship that holds food waste from open ocean and crosses into a special area must apply the 12-nm special-area rule to that waste, not the 3-nm rule that applied when the waste was generated. The reverse holds too: waste retained inside a special area can be discharged under the looser Regulation 4 rule only after the ship has left the area.

Reception facilities: the precondition the master cannot compel

Regulation 6 assumes a network of shore reception facilities that the master cannot create. Regulation 8 of Annex V obliges the governments of parties to ensure the provision of adequate facilities at ports and terminals for the reception of garbage, and the adequacy of that provisioning is the formal trigger for a special area’s discharge restrictions to take effect. The Red Sea wait of over four decades, ended only by Resolution MEPC.382(80) on 1 January 2025, and the still-pending Black Sea, are the operational evidence of how the precondition binds.

The reception network is also what makes Regulation 6 workable in practice. Inside a special area the default is retention, and retention is only sustainable if a facility takes the waste at the next port. Where a port reception facility refuses a category, charges a prohibitive fee, or lacks capacity, the ship retains the waste for a later port, and the reception-facility receipts the ship collects at each call are the documentary evidence that the retained garbage was lawfully landed rather than quietly discharged at sea. Port state control inspections under the Paris MoU, the Tokyo MoU, and other regional regimes examine those receipts against the garbage record book entries; a ship that records frequent retention but cannot produce the corresponding landing receipts is investigated for unauthorized sea discharge.

The reception regime is uneven across the eight areas. The Baltic operates the no-special-fee model under the HELCOM Convention 1992, which removes the cost incentive to discharge at sea by folding garbage reception into the standard port dues. The North Sea ports are dense and well-provisioned. The Mediterranean is mixed, strong at the large Western European ports and variable at some Eastern Mediterranean and North African ports. The Wider Caribbean is uneven, which is part of why the in-area cargo-residue pathway under Regulation 6.1.2 has any relevance there. The newly active Red Sea is the area to watch, because the discharge restrictions now apply from 1 January 2025 while reception provisioning along the Red Sea coasts is still developing.

How Regulation 6 differs from the outside-area Regulation 4

The cleanest way to hold the special-area regime in mind is as a set of differences from the outside-area Regulation 4 rule that the same ship applies elsewhere. The differences run on four lines, and they are the differences a master must apply the moment the ship crosses a special-area boundary.

Food waste distance changes. Outside a special area, comminuted food waste goes to sea at 3 nm. Inside, the distance rises to 12 nm. The en-route and 4-knot conditions are the same in both regimes, and comminution to 25 mm is required in both, but the standoff quadruples.

Non-comminuted food waste changes from permitted to prohibited. Outside a special area, non-comminuted food waste may be discharged at 12 nm. Inside, it has no discharge pathway, because comminution is a condition of the special-area food-waste permission. A ship without a working macerator can discharge no food waste at all inside a special area.

Cargo residue changes from a distance rule to a triple condition. Outside a special area, non-HME cargo residue goes to sea at 12 nm, en-route at 4 knots, after the hold is emptied by ordinary means. Inside, the same 12-nm distance applies, but only where both ports lie inside the area and no adequate reception facility exists, which is the exception rather than the rule. HME residue is barred from discharge in both regimes, and barred from any special area absolutely.

Incinerator ash and animal carcasses change from permitted to prohibited. Outside a special area, heavy-metal-free incinerator ash may be discharged at more than 12 nm and animal carcasses as far from land as possible. Inside, both pathways close, and the materials are retained.

The disposal of plastics, domestic waste, cooking oil, operational waste, and e-waste does not change: those categories are prohibited from sea discharge everywhere under Annex V, inside and outside special areas alike, and the only lawful routes are shore reception or, for combustible categories, approved on-board incineration with the ash retained. The full outside-area picture, the overview of the garbage categories, and the garbage record book and placard requirements live in the sibling articles, so a reader who wants the open-sea numbers should read Regulation 4 and the Annex V garbage-discharge overview.

Worked compliance scenario: a Mediterranean transit

A 60,000-tonne grain Panamax loads wheat at a Black Sea port, transits the Bosphorus and the Aegean, and discharges at a Western Mediterranean port, then proceeds in ballast through the Strait of Gibraltar to a North Atlantic load port. The voyage crosses two special-area regimes and one open-ocean leg, and the garbage and cargo-residue handling differs on each.

In the Black Sea, the Annex V special-area discharge restrictions are not yet in effect, so the ship applies the outside-area Regulation 4 rule: comminuted food waste at 3 nm, en-route at 4 knots. The chief mate notes this in the garbage management plan, because a crew that assumes the Black Sea is an active special area would retain food waste unnecessarily, while a crew that misreads the open-ocean rule onto the Mediterranean would discharge unlawfully.

In the Mediterranean, in effect as a special area since 1 May 2009, the ship applies Regulation 6: only comminuted food waste at 12 nm or more, en-route at 4 knots, and everything else retained. The macerated galley waste goes to sea once the ship is clear of the Italian, Maltese, and Spanish coasts and any offshore islands by 12 nm, with each discharge logged in the garbage record book Part I with date, time, position, category, and volume. Plastics, domestic waste, cooking oil, and operational waste accumulate for the discharge-port reception facility.

The wheat cargo residue is handled under the chemistry-then-geography sequence. Wheat is typically non-HME, so it is Category J, but the IMSBC Code declaration is checked rather than assumed. Even as a non-HME residue, the Regulation 6.1.2 in-area discharge pathway does not open, because the next port of destination after the Mediterranean discharge port is a North Atlantic load port outside the special area: the both-ports-inside condition fails. The hold-washing residue is therefore retained for the discharge-port reception facility or, after the ship has cleared the Strait of Gibraltar into the open Atlantic, washed out and discharged at 12 nm under the outside-area Regulation 4 rule. The chief mate records the residue category, the HME determination by reference to the IMSBC declaration, and the disposal route in the garbage record book Part II.

The open-Atlantic leg is the looser regime. Outside any special area, non-HME cargo residue and non-comminuted food waste alike may go to sea at 12 nm, and the held-over Mediterranean residue is discharged there if it was not landed at the Mediterranean port. The scenario shows the planning discipline the regime forces: the same ship, on one continuous voyage, applies three different rule sets keyed to position, and the garbage record book is the contemporaneous proof that each discharge matched the rule applicable at its time and place.

Enforcement and the documentary chain

Regulation 6 is enforced through the same documentary discipline as the rest of Annex V, examined by port state control at the next port of call. The garbage record book is the central document. Inside a special area, the lawful sea discharges are limited to comminuted food waste at 12 nm and the rare Regulation 6.1.2 cargo residue, so a garbage record book that shows sea-discharge entries inside a special area for any other category, or food-waste entries at less than 12 nm, or discharges with the ship not en-route, is on its face non-compliant.

The garbage record book is split into Part I for general garbage and Part II for cargo-residue-related discharges, a structure introduced by Resolution MEPC.295(71) in force from 1 March 2018. Each Part I entry records the date and time, the ship’s position at the start of the operation in latitude and longitude, the garbage category, the estimated volume discharged or landed, the disposal route, and the signature of the officer in charge, with the master countersigning each completed page. Each Part II entry records the cargo type, the HME or non-HME determination by reference to the IMSBC declaration, the holds involved, the estimated volume, and the disposal route. The garbage record book is retained on board for at least two years after the last entry.

A port state control officer cross-checks the garbage record book against the ship’s deck and engine logs, the reception-facility receipts, the cargo manifest, and the voyage track. A food-waste discharge logged inside the Mediterranean at a position 8 nm from the nearest land is a deficiency on its face. A cargo-residue discharge logged inside a special area without the both-ports-inside and no-facility conditions documented is unauthorized. Falsified entries, whether recording sea discharges that did not occur or under-recording retained volumes to suggest a higher lawful sea-discharge fraction, are criminal offenses under most flag-state legislation implementing MARPOL, and the documentary chain is what exposes them. The voyage planning, the segregation discipline, and the record-keeping are not separable from the discharge rule; they are how the discharge rule is proved to have been followed.

Limitations

This article states Regulation 6 as it stands in the consolidated revised Annex V through the amendments in force to mid-2026, and several limitations bind any specific application of it.

The special-area effective dates are the most error-prone element, and they shift. The IMO summary table that many onboard references reproduce was published before Resolution MEPC.382(80) took effect, and still shows the Red Sea with an asterisk as not in effect; the binding position is that the Red Sea Annex V discharge restrictions took effect on 1 January 2025. The Black Sea remains not in effect as of 2026, so a ship there applies Regulation 4, not Regulation 6, in formal legal terms. A reader must check the current IMO special-areas page and the relevant MEPC resolution for the area and date in question rather than rely on a static table, because the effective dates are set by resolution and change.

The HME classification is the hardest substantive judgment, and it sits upstream of Regulation 6. The Category K or J determination rests on the shipper’s IMSBC declaration and the cargo’s GHS environmental hazard categories, and the master is entitled to rely on the declaration absent evident error or fraud. Where the declaration is unclear or contradicted by direct observation, the prudent course is to treat the residue as HME and bar the special-area discharge; the declaration is a presumption, not an absolute defense. The full HME treatment is in the companion article and is summarized here only as the gate to Regulation 6.1.2.

The reception-facility precondition is assumed by the regulation but not within the master’s control. Where a facility refuses a category, overcharges, or lacks capacity, the ship retains the waste, and the same compliance plan can succeed at one port and stall at the next. The EU Port Reception Facilities Directive 2019/883 overlays the IMO regime in EU ports with its own delivery, advance-notification, and cost-recovery rules, so a ship calling at an EU port inside the Mediterranean, North Sea, or Baltic special area must satisfy both Annex V and the Directive, which are aligned in intent but not identical in detail.

Distance measurement near complex coastlines and ice shelves is a practical limit on the 12-nm rule. The nearest land is the nearest point in any direction, including offshore islands and, in the Antarctic, ice shelves, and the ECDIS-displayed contour is the operational reference. The Antarctic case is stricter still, because the Polar Code and the Antarctic special-area regime add retention requirements beyond the bare 12-nm food-waste pathway. A reader applying the 12-nm rule in polar waters must read it together with the Polar Code, not in isolation.

This article does not restate the full garbage-category table, the garbage management plan and placard requirements, or the outside-area distances, which are covered in the sibling articles. It also does not address the platform-specific regime for fixed and floating installations, which imports a 12-nm comminuted-food-waste rule of its own independent of whether the platform sits inside a special area. The boundary between Regulation 6 and those neighboring rules is itself a limitation: a ship within 500 meters of an offshore platform inside a special area applies the stricter of the platform rule and Regulation 6, and the master must read the two together.

See also

• MARPOL Annex V on garbage discharge: the overview of the full garbage-discharge regime, categories, and record-keeping.
• MARPOL Annex V hub: the parent overview article on Annex V.
• Regulation 4: discharge outside special areas: the looser open-sea counterpart to Regulation 6.
• Regulation 5: special requirements for platforms: the offshore-installation regime.
• Regulation 7: exceptions: the safety and accident exceptions that survive inside special areas.
• Regulation 10: placards, garbage management plan, and record-keeping: the documentary regime.
• HME cargo residues and e-waste: the chemistry test that gates Regulation 6.1.2.
• MARPOL Convention: the overarching pollution-prevention framework.
• Antarctic special area and Polar Code: the strictest Annex V special area.
• IMSBC Code: the cargo declaration that carries the HME determination.
• Port state control: the enforcement of the documentary chain.