MARPOL 73/78 in Nutshell

Table of Contents

What is MARPOL 73/78?

The International Convention for the Prevention of the Pollution of the Sea by Oil (OILPOL) dating from 1954 was at the basis of the Convention. The shipwreck of the Torrey Canyon in 1967, the largest oil disaster at the time, was a key motivator for establishing the Convention. The Convention was signed on 17 February 1973, but only went into effect following the addition of the Protocol in 1978. After a sufficient number of countries had ratified the Convention, it went into force on 2 October 1983. As at 31 December 2005, 136 countries had signed the Convention. These countries represent 98% of the transport by ship, measured by weight.

It is the most important international convention for the prevention of pollution of the maritime environment by ships due to operational or incidental causes. The Convention currently comprises six technical annexes. Special areas with strict controls on operational discharges are included in most annexes.


To minimize the pollution of Seas, including dumping, Oil and Exhaust Pollution. To prevent the Marine Environment through the COMPLETE ELIMINATION of Pollution by oil and other harmful substances and minimize accidental discharge of such substances.

List of Annexes under MARPOL

  • Annex I: Regulation for Prevention of Pollution by Oil, Oct 2nd, 1983
  • Annex II: Regulation for Control of Pollution by NLS in Bulk, Oct 2nd, 1983
  • Annex III: Regulation for Prevention of Pollution by Harmful Substances in Packaged Form, July 1st, 1992
  • Annex IV: Prevention of Pollution by Sewage from Ship, Sep 27, 2003
  • Annex V: Prevention of Pollution by Garbage from Ships, Dec 31st, 1988
  • Annex VI: Prevention of Air Pollution from Ships, May 19th, 2005

Few definitions that you will come across in MARPOL

  • Crude Oil: Means any liquid Hydrocabon mixture occurring naturally in the earth.
  • Oil: Oil means petroleum in any form including crude oil, fuel oil, sludge, oil refuse and refined products (other than petrochemicals which are subject to the provisions of Annex II of MARPOL 73/78) and, without limiting the generality of the foregoing, includes the substances listed in appendix I to this Annex.
  • Slop Tank: A tank specifically designated for the collection of tank drainings, tank washings and other oily mixtures.
  • Nearest Land: It means that the base line from which the territorial is established in accordance with the International Laws
  • Special Areas: It means Sea Areas where because of Recognised Technical Reasons to its Oceanograhical and Ecological Condition to the particular characteristics of its traffic the adoption of special mandatory method for the prevention of sea pollution by oil required.

MARPOL Annexures in detail

Annex I- Regulation for the Prevention of Pollution by Oil

Annex I of MARPOL 73/78 deals with prevention of pollution by oil from operational measures as well as from accidental discharges; the 1992 amendments to Annex I made it mandatory for new oil tankers to have double hulls and brought in a phase-in schedule for existing tankers to fit double hulls, which was subsequently revised in 2001 and 2003.

Came into force: Oct 2nd, 1983

Discharge Criteria for MARPOL Annex I (Regulation 9)

For an Oil Tanker:

(i) the tanker is not within a special area;
(ii) the tanker is more than 50 nautical miles from the nearest land;
(iii) the tanker is proceeding en route;
(iv) the instantaneous rate of discharge of oil content does not exceed 30 litres per nautical mile;
(v) the total quantity of oil discharged into the sea does not exceed for existing tankers 1/15,000 of the total quantity of the particular cargo of which the residue formed a part, and for new tankers 1/30,000 of the total quantity of the particular cargo of which the residue formed a part;
(vi) the tanker has in operation an Oil Discharge Monitoring and Control System (ODMCS) and a Slop Tank arrangement as required by Regulation 15 of this Annex.

Discharges Outside Special Areas (from Main Engine Spaces of a ship of 400 GRT and above, other than Oil Tanker) (Regulation 9.b)

  1. the ship is proceeding en route;
  2. the oily mixture is processed through an oil filtering equipment meeting the requirements of regulation 14 of this Annex;
  3. the oil content of the effluent without dilution does not exceed 15 parts per million;
  4. the oily mixture does not originate from cargo pump-room bilges on oil tankers; and
  5. the oily mixture, in case of oil tankers, is not mixed with oil cargo residues.

Discharges Inside Special Areas (from Main Engine Spaces of a ship of 400 GRT and above, other than Oil Tanker)

  • Any discharge into the sea, Oily Mixture form ship of 400 GRT and above are prohibited except when all the above conditions are satisfied.
  • In Antarctic Area, any discharge into the sea of Oil or any Oily Mixture is prohibited.

Cargo Spaces, Outside Special Area:

  • Tanker should be 50 nm away from the nearest land,
  • The ship must be proceeding en route,
  • Instantaneous Rate of Discharge (IRD) does not exceed 30 liters/nm,
  • The total quantity of oil discharge does not exceed 1/30,000 of last cargo loaded,
  • The tanker vessel has operational ODMCS and slops tank arrangement,
  • The tanker is not within Special Area.

The Record of ODMCS must be maintained on-board at least for three years

Cargo Spaces, Inside Special Area:

Any discharge of Oil or Oily Mixture of Cargo Space into the sea is prohibited.

Special Areas of Annex I

  • The Red Sea,
  • The Black Sea,
  • Baltic Sea,
  • Mediterranian Sea,
  • Antarctic Sea,
  • Southern South Africa,
  • The North West of European Water,
  • The Gulf of Aden,
  • The Gulf Area (Persian Gulf),
  • Oman Area of Arabian Sea

Certificates under Annex I

  • International Oil Pollution Prevention Certificate with Supplement (IOPP) (Regulation 7 of Annex I of MARPOL)
    • An International Oil Pollution Prevention Certificate shall be issued by the Administration, after an initial or renewal survey in accordance with the provisions of Regulation 6 of MARPOL Annex I,
      The Certificate shall be issued for a period specified by the Administration, which shall not exceed FIVE years (Regulation 10.1)
    • IOPP Certificate is issued to any oil tanker of 150 GRT and above and any other ships of 400 GRT and above which are engaged in voyages to ports or offshore terminals,
    • IOPP consists of two supplements:
    • Draft of IOPP (Regulation 9)
  • Oil Record Book (ORB), required as per Reg 20 of Annex I
    • Part 1: (Machinery Spaces)
      For Oil Tankers of 150 GRT and above
      For ships other than Oil Tanker and of 400 GRT and above
    • Part 2: Cargo/ Ballast Operation
      For Oil Tankers of 150 GRT and above
  • Shipboard Oil Pollution Emergency Plan (Regulation 26)
    • For Tankers of 150 GRT and above
    • For vessels other than 400 GRT and above
      shall carry a SOPEP Manual approved by the Administration
  • ODMCS Manual: Oil Discharge Monitoring and ControlSystem Manual should be carried on board as approved by the Administration along with the record of the last THREE years.
  • Crude Oil Washing Manual (COW Manual)
  • Record of ODMCS for last Oil Ballast Operation Voyage
    • Oil Tankers of 150 GRT and above (shall be fitted)
      Recording Device (Continuous Record of Discharge, liter/nm)
    • Total quantity discharged
    • The Oil Content (ppm) and the Rate of Discharge (liter/nm)
    • The record shall be identified as time and date and will be kept for at least THREE years
  • CAS (Conditional Assessment Scheme, According to Reg 20): CAS Survey is carried out concurrent with the first Intermediate or Renewal Survey. CAS applies to:
    • Ships after 5 April 2005
    • Ships of age more than 15 years
  • Subdivision and Stability Information (Reg 28)

  • Ship-to-Ship Operation Plan and Record of Ship-to-Ship Operation

Annex II- Regulation for Prevention of Pollution by Noxious Liquid Substance in Bulk

Came into force: Oct 2nd, 1983

Annex II gives details about the discharge criteria and measures for the control of pollution by Noxious Liquid Substances carried in bulk; some 250 substances were evaluated and included in the list appended to the Convention; the discharge of their residues is allowed only to reception facilities until certain concentrations and conditions (which vary with the category of substances) are complied with.
In any case, no discharge of residues containing noxious substances is permitted within 12 miles of the nearest land.  

Categories of Noxious Liquid:

  • Category X– NLS which is discharged into the sea from tank cleaning or deballasting operation are deemed to present a major hazard to either marine resources or human health, therefore, justified for the prohibition of the discharge into the marine environment.
  • Category Y– NLS which presents a hazard to either Marine Resources or Human Health so justified on the limitation on the quantity and quality of discharge into the marine environment.
  • Category Z NLS which present minor hazard to Marine Resources or Human Health so justified less Restriction on the quantity and quality of discharge into Marine Environment,
    Other Substances- Substances which DOES NOT present any harm to marine resources, human health, amenities, or other legitimate use of the sea when discharged into the sea from tank cleaning and deballasting operation. The discharge of Bilge or Ballast water or other mixture containing only these mixtures referred to as OS.

Special Areas of Annex II

  • Antarctic Sea
  • Black Sea
  • Baltic Sea

Discharge Standards: (Reg 13.2 of Annex II)

  • For residues of Categories X, Y, Z, or Ballast Water tank washing or other mixture containing such substance pre-wash. It is mandatory for NLS shall be carried out before the vessel arrives at the port and discharge residue to the port facility.
    Strip the tan kand piping, tank cleaning, cargo handling, and per Procedure and Arrangement (P&A) Manual.
  • Mandatory pre-wash for Categories X and Y
  • Ship should be en route at a safe speed of at least SEVEN knots, for self-propelled vessels and FOUR knots, in case of a vessel that is not self-propelled.
  • Distance from nearest land not less than 12 nautical miles
  • Depth of water less than 25 meters
  • Discharge is made before the waterline through underwater discharge outlet, not exceeding the maximum rate at which the underwater outlet is designed

Discharge of Residue of Category X:

  • The tank which has unloaded category X shall have pre-washed before the ship leaves the port.
  • The resulting residue shall be discharged to a reception facility unit. The concentration of effluents is a or below 0.1% by weight and remaining tank washing shall continue to discharge to the reception facility until the tank is empty.
  • This is to be done as per P&A Manual, the appropriate entry must be made in Cargo Record Book and enclosed by Surveyor.

Certificates and Documents required as per Annex II of MARPOL

  • IPPC: International Pollution Prevention Certificate for the discharge of NLS in bulk
    • shall be issued after initial or renewal survey by the administration
      issued for a period specified by the Administration, not exceeding 5 years
    • COF (Certificate of Fitness)
  • P&A Manual: The main purpose of the P&A Manual is to identify:
    • the physical arrangements
    • all operational procedures with respect to cargo handling, tank cleaning, slop handling, cargo tank ballasting and deballasting
  • SMPEP (Shipboard Marine Pollution Emergency Plan) (Regulation 17) for ship carrying NLS
    • Required by every ship of 150 GRT and above when it is required to carry NLS in bulk
    • shall provide guidelines for the development of SMPEP for NLS and Oil
    • Procedures to be followed by Masters and other persons having charge of the ship to report NLS Pollution Incident
  • Cargo Record Book:
    • After completion of any special operation it shall be recorded in Cargo Record Book (CRB). 
    • Each entry shall be signed by the Officer-in-charge of the operation
    • A completed CRB verifies that all operational requirement has been observed, such as:
      • unloading, stripping and pre-wash operation
      • discharge into the sea of NLS
      • disposal of tank washing, etc.
  • IBC Code
  • Officer Specialized Chemical Tanker Certificate

Annex III- Prevention of Pollution by Harmful Substances Carried by Sea in Packaged Form

Came Into Force: 1 July 1992

Annex III of MARPOL 73/78 contains general requirements for the issuing of detailed standards on packing, marking, labeling, documentation, stowage, quantity limitations, exceptions, and notifications.

Harmful Substance: those substances which are identified as marine pollutants in the International Maritime Dangerous Goods Code (IMDG Code) or which meet the criteria in the Appendix of Annex III.
Packaged Form: Defined as a form of containment specified for harmful substances in the IMDG Code.

Annex III of MARPOL 73/78 applies to all ships carrying harmful substances in packed form

Packing shall be adequate to minimize hazards to the marine environment.

Special Areas for Annex III


Certificates required as per MARPOL Annex III


Annex IV- Regulation for the prevention of Pollution by Sewage

Entered into force on 27 September 2003

Annex IV of MARPOL 73/78 talks about requirements to control pollution of the sea by sewage; the discharge of sewage into the sea is prohibited, except when the ship has in operation an approved sewage treatment plant or when the ship is discharging comminuted and disinfected sewage using an approved system at a distance of more than three nautical miles from the nearest land; sewage which is not comminuted or disinfected has to be discharged at a distance of more than 12 nautical miles from the nearest land.

Some terms used in Annex IV

  • Holding Tanks- Tanks which are used for collection and storage of sewage
  • Communitor: Communitor is used to cut the sewage material at a size of less than 25 mm


The provision of this Annex shall apply to following ships engaged in international voyage an:

  • are of 400 GRT and above
  • ships of less than 400 GRT which are certified to carry more than 15 persons


– comes from Toilet, Urinals
– comes from all Domestic Sources except Toilet, Sinks, Shower, Washing, etc.

Special Areas:

  • Baltic Sea (Jan 1, 2013)
  • No discharge in US waters

Discharge Criteria for Annex IV:

  • Sewage from Holding Tank should not be discharged instantly but at a moderate rate when the ship is en route and proceeding with her speed not less than 4 knots,
  • The ship is discharging comminuted or disinfected sewage using a system approved by Administration,
  • Comminuted sewage to be discharged at THREE nm from the nearest land
  • Non-comminuted sewage to be discharged at 12 nm from the nearest land,
  • Rate of discharge to be approved by the Administration,
  • The Test Result of the Plant are laid down in the Ship International Pollution Prevention Certificate (ISPP) Certificate,
  • Additionally, the effluent shall not produce visible floating solid nor cause discoloration of surrounding waters

Sewage System:

Every ship shall be equipped with one of following sewage system:

  • A Sewage Treatment Plant of type-approved administration taking into account the standard test method developed by Administration, 
  • A Sewage comminuting and disinfecting system of a type approved by Administration and shall be fitted with temporary storage of Sewage when the ship is less than THREE nm away from Nearest Land, 
  • A holding tank of capacity to the satisfaction of the Administration for the retention of all sewage having regard to the operation of the ship and the number of persons on-board the ship.

Standard Discharge Connection for Sewage:

According to Reg 10 of Annex IV the size of pipeline system used for discharge:

  • Outer Dia- 210 mm,
  • Inner Dia- As per pipe’s outer dia,
  • Bolt Circle Dia: 17 mm
  • Slots in flange: 4 holes, 18 mm dia, Equidistantly,
  • Flange Thickness: 16 mm,
  • Bolt Slots- 4 x 16 mm Dia

Annex V- Regulation for prevention of Pollution by Garbage from Ship

Annex V of MARPOL 73/78 deals with different types of garbage and specifies the distances from land and the manner in which they may be disposed of; the most important feature of the Annex is the complete ban imposed on the disposal into the sea of all forms of plastics.

Definition of Garbage:

Garbage means all kind of Domestic and Operational Waste excluding fresh fish and parts those of generated during normal operation of the ship and liable to be disposed off continuously or periodically, except those substances which are defined or listed in other Annexes to the present Convention.

Application of Annex V

Applies to all ships/ vessels of any type operating in Marine environment from Merchant Ships to FIxed and Floating platforms to Non-commercial ships like pleasure crafts
Prohibits the discharge of Plastic anywhere into the sea and severely restricts the discharge of other garbage from the ship in coastal water and special areas

Special Areas for Annex V

  • Baltic Sea
  • Black Sea
  • Gulf Area
  • Mediterrane Sea
  • North Sea
  • Red Sea
  • The Wider Caribbean Sea (including the Gulf of Mexico and Caribbean Sea)

Note: Discharge provision of the revised Annex V came into force on Jan 1st, 2013

Special Circumstances:

According to Reg 6.1.2 MARPOL Annex V, the discharge of garbage shall be allowed if:
Both the port of departure and next port of destination are within the special area and the ship will not transit outside the special area between ports
If no adequate reception facilities available at both the ports

Certificates/ Documents required under MARPOL Annex V:

i) Garbage Record Book:

  • GRB shall be carried by every vessel of 100 GRT and above, a vessel certified to carry 15 persons and more and for every fixed floating platform
  • The entry of every discharge shall be made with Date of Discharge and Signed by Officer In-charge
  • The entry of discharge to a Reception facility
  • The entry of each discharge with Date, Time and Position of Ship in Lat and Long, Description of Garbage and Estimated amount of Garbage tobe entered in Garbage Record Book
  • Once a Garbage Record Book is fully complete it shall be kept on board for at least TWO yeats for inspection,
    Each complete page of Garbage Record Book shall be signed by Master

ii) Garbage Management Plan: (Discharge Depends on Categories)

  • All vessels of 100 GRT and above, which are certified to carry 15 people or more must have a Garbage Management Plan (GMP)
  • A Designated Person should be responsible to carry out the plan
    A Garbage Management Plan should be in working language of the crew
    Should contain written procedure for the use of equipment on board

Colour Coding for Garbage:

  • Green: Flammable Substances like Paper, Cardboards, Rags
  • Red: Non-flammable substances like Glass, Bottle, Metal
  • Yellow: Plastic
  • Blue: Food Waste
  • Black: Ash, generated from Incinerator

Annex VI- Prevention of Air Pollution from Ship

Annex VI of MARPOL 73/78 sets limits on Sulphur Oxide and nitrogen oxide emissions from ship exhausts and prohibits deliberate emissions of ozone-depleting substances; designated emission control areas set more stringent standards for SOx, NOx, and particulate matter.  A chapter adopted in 2011 covers mandatory technical and operational energy efficiency measures aimed at reducing greenhouse gas emissions from ships. 

Special Areas for Annex VI:

  • Baltic Sea (SOx),
  • North Sea (SOx),
  • North America (SOx and NOx),
  • United States Caribbean Sea (SOx and NOx)

Annex VI applies to:

  • Every ship of 400 GRT and above and every fixed and floating drilling rigs and other platforms are under the applicability of this Annex.
  • applies on every Marine Diesel Engine with a power output of more than 130 kW installed in a ship
  • applies to every Marine Diesel Engine with a power output of MORE THAN 130 kW that undergoes a major conversion on or after Jan 4th, 2000
  • ECA: Emission Control Area; It means an area where the adoption of Special Mandatory Measure for Emission from a ship is required to prevent, reduce and control Air Pollution from NOx and SOx and particular matter
  • SECA: Sulphur Oxide Emission Control Area
  • NECA: Nitrogen Oxide Emission Control Area

Discharge Criteria for Annex VI:

Inside SECA (SOx)
i. Before July 1st, 2010- 1.5% Mass by Mass
ii. Between July 1s, 2010 to Jan 1st, 2015- 1.01% Mass by Mass
iii. After Jan 1st, 2015- 0.1% Mass by Mass

Outside SECA (SOx)
i. Before Jan 1st, 2012- 4.5% Mass by Mass
ii. Between Jan 1st, 2012 to Jan 1st, 2020- 3.5% Mass by Mass
iii. After Jan 1st, 2020- 0.5% Mass by Mass

Ships within SECA must fulfil following conditions:
i. Sulphur content should be within the limit of 0.5% for OUTSIDE SECA and 0.1% for INSIDE SECA
ii. Exhaust cleaning system to reduce Sulphur Oxide 6 gm/KWH
iii. Any other method to reduce SOx as above

Discharge Criteria for NECA (NOx)

List of Certificates required as per Annex VI:

  • IAPP: International Air Pollution Prevention Certificate; Valid for FIVE years
  • SEEMP (Ship Energy Efficiency Management Plan); Mandatory for all vessels. It is a Management Document intended to improve Energy Efficiency onboard ship through the improvement of Ship Operations, such as slowing down speed route planning, taking sea and current condition in the account, proper maintenance.
  • EEDI (Energy Efficiency Design Index): It is required on certain types of ships which are constructed after Jan st 2013 or any major conversion before Jan 1st, 2013. EEDI is an index that estimates the performance of the ships in terms of energy efficiency like all components of the ship, influencing fuel, technical development, etc.
    IEEC (International Energy Efficiency Certificate): It is applicable to vessels more than 400 GR used for a survey of IAPP after Jan 1st, 2013. It is valid for ships’ life unless the ship undergoes a major conversion or change of flag.

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