MARPOL and Discharge Regulations — What May Go Over the Side, and Where

What the rule requires

Plastic is absolute

No person on board any ship may discharge plastic, or garbage mixed with plastic, into the sea or into the navigable waters of the United States, and the section names synthetic ropes, synthetic fishing nets and plastic garbage bags as examples. All garbage containing plastic requiring disposal must be discharged ashore or incinerated 33 CFR §151.67.

The operative trigger is the presence of plastic. There is no distance test, no tonnage test and no special-area test to work through. If a question about garbage disposal offers you an answer with a distance in it and plastic is in the waste, the distance is a distractor.

Note what counts as plastic: for purposes of these regulations, "all plastics" means all garbage consisting of or including plastic in any form, including synthetic ropes, synthetic fishing nets, plastic garbage bags and incinerator ashes from plastic products 33 CFR §151.05.

You burn plastic wrappers in the shipboard incinerator 40 miles offshore. May the ash go over the side?

No. Incinerator ashes from plastic products are themselves within the definition of "all plastics" under §151.05, so the ash is plastic and §151.67 prohibits discharging it. Burning satisfies the disposal requirement only if the residue is then landed ashore.

Oil and oily mixtures: 15 ppm, and the equipment running

For a vessel other than an oil tanker — and for the machinery space bilges of a tanker — discharge of oil or oily mixture into the sea is prohibited unless every condition in the governing paragraph is satisfied. Read it as a prohibition with exceptions, not as a permission with limits.

More than 12 nautical miles from the nearest land, all six of these must hold: the mixture does not originate from cargo pump room bilges; it is not mixed with oil cargo residues; the ship is not within a special area; the ship is proceeding en route; the oil content of the effluent without dilution is less than 15 ppm; and the ship has in operation oily-water separating equipment, a bilge monitor, bilge alarm or combination thereof 33 CFR §151.10.

Within 12 nautical miles of the nearest land the conditions are the same on cargo pump room bilges and cargo residues, the effluent must not exceed 15 ppm, the separating equipment must be in operation, and that equipment must be fitted with a 15 ppm bilge alarm of the approved type.

Two consequences candidates miss. Beyond 12 miles but not proceeding en route, you fall back to the within-12-mile conditions, including the bilge alarm. And where the vessel cannot meet any of these, the person in charge of an oceangoing ship must ensure the oily mixtures are retained on board or discharged to a reception facility; an oceangoing tanker or other oceangoing ship of 400 gross tons or more must give the port or terminal 24 hours' notice of the time, type and volume before entering.

Clean ballast and segregated ballast are outside these paragraphs entirely. Chemicals introduced to circumvent the discharge conditions are prohibited, and inside the navigable waters of the United States the Federal Water Pollution Control Act section 311(b)(3) and 40 CFR Part 110 govern all discharges of oil or oily mixtures.

The oil sections have an applicability gate the garbage sections do not: §§151.09 through 151.25 reach a U.S. vessel engaged in international voyages, certificated for ocean service, certificated for coastwise service beyond three nautical miles from land, or operating at any time seaward of the territorial sea, and they do not reach a U.S. or Canadian vessel operated exclusively on the Great Lakes and their connecting and tributary waters or exclusively on the internal waters of the United States and Canada 33 CFR §151.09.

Eight miles off Point Loma, en route, your bilge is dirty and the 15 ppm bilge alarm on the separator is inoperative. What are you required to do?

Retain the oily mixture on board or land it to a reception facility. Within 12 miles the separating equipment must be in operation and fitted with a working 15 ppm bilge alarm; with the alarm out you cannot satisfy §151.10(b), so no overboard discharge is lawful regardless of how clean you believe the effluent to be.

Inside a special area

The Annex V special areas include the Wider Caribbean region, which comprises the Gulf of Mexico and the Caribbean Sea proper, along with the Mediterranean, Baltic, Black Sea, Red Sea, Gulfs, North Sea and Antarctic areas. The discharge restrictions are in force in the Wider Caribbean, Mediterranean, Baltic, North Sea, Gulfs and Antarctic 33 CFR §151.53.

Any candidate working out of a Gulf port operates inside an in-force Annex V special area every day. That same water is not an Annex I special area — the Annex I list runs to the Mediterranean, Baltic, Black Sea, Red Sea, Gulfs, Gulf of Aden, Antarctic, North West European waters, the Oman area and Southern South African waters, with restrictions effective in the Mediterranean, Baltic, Black Sea and Antarctic 33 CFR §151.13. Garbage and oil do not share a map.

Within an Annex V special area, no garbage may be discharged except as the section allows. Food wastes only, and only while the ship is en route, as far as practicable from the nearest land or nearest ice shelf but not less than 12 nautical miles, after processing through a grinder or comminuter, and not contaminated by any other garbage type 33 CFR §151.71. Cargo residues that cannot be recovered by commonly available unloading methods have a narrow path: nothing harmful to the marine environment, both the departure and next destination ports inside the special area with no transit outside it, no adequate reception facilities at those ports, and then not less than 12 nautical miles out. Mixtures of garbage with different discharge requirements are retained on board for disposal ashore or discharged under the more stringent requirement.

On the oil side inside an Annex I special area, a ship of 400 gross tons or over and any oil tanker may not discharge oil or oily mixture at all; a ship of less than 400 gross tons other than a tanker may not discharge unless the effluent without dilution does not exceed 15 ppm. In the Antarctic area discharge of oil or oily mixture from any ship is prohibited, and ships operating there must carry tankage sufficient to retain all oily mixtures for landing outside the area. A vessel on a voyage only part of which lies in a special area may discharge outside it under §151.10.

Placards, plans and records, by vessel size

• Placard — required on a manned U.S. ship of 26 feet or more in length, other than a drilling rig or platform 33 CFR §151.51. Each must be at least 20 cm (8 in) wide by 12½ cm (5 in) high, of durable material and legible, displayed in prominent, readily accessible locations in sufficient numbers to be read by crew and passengers; the COTP may require additional placards and specify their locations 33 CFR §151.59.
• Garbage management plan — a manned oceangoing U.S. ship of 40 feet or more in length that is engaged in commerce or equipped with a galley and berthing.
• Recordkeeping — a manned oceangoing ship of 400 gross tons and above, or a manned ship certified to carry 15 or more persons on international voyages. A six-pack or a 90-ton small passenger vessel on domestic runs is below this threshold.
• Small vessels are not exempt from the rest of it. Each uninspected vessel must meet the garbage discharge, waste management plan and placard requirements of 33 CFR part 151 applicable to it 46 CFR §25.50-1, and a Subchapter T small passenger vessel must comply with the applicable design, equipment, personnel, procedure and record requirements of 33 CFR parts 151, 155 and 156 46 CFR §184.702.

The placard must notify the reader of the operating requirements of §§151.67 through 151.73 as they apply to that vessel, and should prominently state that discharge of all garbage into the navigable waters of the United States and all other waters is prohibited except as specifically allowed, that discharge of all forms of plastic into all waters is prohibited, that violators are liable for civil and/or criminal penalties, and that regional, state and local restrictions may also apply.

Reporting a discharge

The master, person in charge, owner, charterer, manager or operator must report the particulars of the incident without delay whenever there is a discharge resulting from damage to the vessel or its equipment or made to secure the safety of the vessel or save a life at sea, a discharge exceeding what §151.10 or §151.13 permits, a discharge of marine pollutants in packaged form, or a probable discharge resulting from damage 33 CFR §151.15.

The report goes by radio whenever possible, otherwise by the fastest channel available at the highest priority, to the appropriate agency of the country in whose waters the incident occurred and to the nearest Captain of the Port or the National Response Center at 800-424-8802. It must carry the vessel's identity, the type of harmful substance, the time and date, the geographic position, wind and sea conditions, relevant details of the vessel's condition, a statement or estimate of the quantity discharged or likely to be discharged, and assistance and salvage measures. Supplement it as developments occur. A report made under this section also satisfies 46 CFR 4.05-1 and 4.05-2 where those apply.

For the probable-discharge judgement the section lists the factors: position and proximity to land or navigational hazards, weather, tide current, sea state, traffic density, the nature of the damage, and failure or breakdown of machinery or equipment — such damage arising from collision, grounding, fire, explosion, structural failure, flooding, cargo shifting, or failure of steering gear, propulsion, the electrical generating system or essential navigational aids.

A person who violates these regulations is liable for a civil penalty for each violation, and each day of a continuing violation is a separate violation; a knowing violation is a class D felony, and the vessel itself is liable in rem 33 CFR §151.04. At a U.S. port the Coast Guard may inspect for compliance and the COTP or OCMI may detain a non-complying vessel 33 CFR §151.23.

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Telling it apart: classify the waste stream before anything else

The single criterion is how §151.05 classifies the substance. Get that wrong and you apply the wrong section flawlessly.

• Plastic — garbage, and the only stream with no discharge condition whatever. Most often misfiled: ash from burned plastic, which the definition captures.
• Food waste — garbage, and the only stream with a discharge path inside an in-force special area. Misfiled: treating ground paper or glass as qualifying because it will pass a screen.
• Oily bilge water — not garbage. Operational wastes expressly exclude bilge water, so §151.10 governs, not the Annex V sections. Misfiled: logging machinery-space slops as operational waste.
• Graywater — drainage from dishwater, shower, laundry, bath and washbasin drains, written out of both domestic wastes and operational wastes. Misfiled: the galley sink drain answered as food waste.
• Cargo residues — garbage, dischargeable in a special area only under the four conditions of §151.71(c). Misfiled: cargo dust remaining on deck after sweeping, which the definition excludes from cargo residues.
• Fresh fish and parts thereof generated by fishing during the voyage — outside the definition of garbage. Fishing gear, by contrast, is inside it.

Working a question

You are master of a 95-gross-ton, 78-foot inspected passenger vessel, 15 nautical miles south of Grand Isle, Louisiana, proceeding en route at 12 knots. The galley has a bag of food scraps, and the bag also holds plastic drink cups.

1. Classify the stream. Food scraps are food wastes and therefore garbage; the cups are plastic. Two streams in one bag.
2. Fix your area. The Gulf of Mexico lies within the Wider Caribbean region, an Annex V special area in which the discharge restrictions are in force. The special-area rules apply, not the general ones.
3. Test the food waste against §151.71(b). En route — yes. Twelve miles or more from the nearest land — yes at 15 miles. Ground through a comminuter — only if you have one and use it. Not contaminated by any other garbage type — fails, because the plastic cups are in the bag.
4. Apply the mixture rule. Garbage with different discharge requirements is retained on board for disposal ashore or discharged under the more stringent requirement. The more stringent requirement here is the plastic prohibition, which permits nothing.
5. Act. Nothing goes over the side. Separate the cups from the scraps and land the whole lot, or separate them, grind the food waste and discharge that alone at 15 miles while en route.
6. Check the paper. At 78 feet the vessel needs placards, and at 40 feet or more with a galley and berthing it needs a garbage management plan. At 95 gross tons on a domestic run the Annex V recordkeeping threshold of 400 gross tons is not reached.

Where candidates lose the point

Answering that grinding to 25 mm makes garbage dischargeable in a special area. The 25 mm screen figure appears in §151.61 as the capability standard the Coast Guard verifies for grinders used to discharge garbage between 3 and 12 nautical miles from nearest land 33 CFR §151.61. Inside a special area, grinding is one of four conditions on food waste alone; ground paper or glass has no discharge path there at all.

Treating "more than 12 miles" as authority to pump bilges. The distance is one of six conditions, and the two that catch candidates are proceeding en route and equipment in operation. Stopped and pumping beyond 12 miles puts you under the within-12-mile paragraph, alarm included.

Assuming a small uninspected vessel is outside part 151. The Annex V sections reach vessels of U.S. registry or nationality, expressly including recreational and uninspected vessels, wherever located — and 46 CFR §25.50-1 says the same thing from the other direction.

Naming the wrong recipient for the report. The answer is the nearest Captain of the Port or the National Response Center. Options offering the EPA, the Corps of Engineers or the vessel's classification society are there to collect candidates who remember only that "somebody must be told."

Carrying the Annex I special-area map over to garbage. The Gulf of Mexico is a special area for garbage and is not one for oil. Two separate lists, in two separate sections.

Check yourself

You are 20 miles offshore in the Gulf of Mexico with a bag of ground food waste and a separate bag of paper plates and metal cans. What may be discharged?

The ground food waste, provided you are en route, at least 12 miles from the nearest land, and it is not contaminated by any other garbage type. The paper and metal have no discharge path — inside an Annex V special area §151.71 permits food wastes, and cargo residues and non-harmful cleaning agents under their own narrow conditions, and nothing else.

Your 62-foot uninspected fishing vessel is 30 miles out. A worn-out nylon trawl net needs disposal. Over the side or back to the dock?

Back to the dock. A synthetic fishing net is named in §151.67, and plastic may not be discharged into the sea at any distance. Fishing gear is also garbage under the §151.05 definition. Distance offshore never enters the analysis.

Underway 6 miles off the beach, you discover a fuel line has been weeping into the bilge and some of it has gone overboard through the bilge pump. What are you required to do about notification?

Report the particulars without delay by radio if possible, or the fastest available channel at highest priority, to the nearest COTP or the National Response Center at 800-424-8802. A discharge in excess of what §151.10 permits is a reporting trigger, and within 12 miles an unmonitored bilge pump discharge cannot meet §151.10(b). Include position, time, substance, estimated quantity, wind and sea, the vessel's condition and salvage measures.

What is the shortest vessel that must post a MARPOL garbage placard, and what does the placard have to say about plastic?

A manned U.S. ship of 26 feet or more in length, other than a drilling rig or platform, per §151.51(e). The placard must state that the discharge of all forms of plastic into all waters is prohibited, along with the general garbage prohibition, the penalties, and the possibility of regional, state and local restrictions.

Your 340-gross-ton vessel, not a tanker, is in the Baltic Sea. May you discharge machinery space bilge water?

Yes, if the effluent without dilution does not exceed 15 ppm. Under §151.13(b)(2), a ship of less than 400 gross tons other than an oil tanker may discharge within a special area on that condition. At 400 gross tons or over, or on any tanker, the answer in a special area would be no discharge.

Laundry and shower drainage on a 90-foot passenger vessel — is it garbage under these regulations?

No. Graywater is drainage from dishwater, shower, laundry, bath and washbasin drains, and the §151.05 definitions exclude graywater from both domestic wastes and operational wastes, the two categories that would otherwise bring it inside the definition of garbage.

You discharged bilge slops that you believed met 15 ppm but the separator had been secured. The Coast Guard boards you in port. What is your exposure, and what may the COTP do with the vessel?

A civil penalty for each violation, with each day of a continuing violation counting separately; a knowing violation is a class D felony, and the vessel is liable in rem. On top of penalties, a vessel not complying with part 151 may be detained by order of the COTP or OCMI until it can proceed to sea without unreasonable threat of harm to the marine environment, though the order may permit a move to the nearest suitable shipyard.