This international convention was adopted by the International Maritime Organization (IMO) in 1973, and later updated in 1978 after several severe tanker accidents. The combined instrument (MARPOL 73/78) entered into force on 2 October 1983.
MARPOL has been updated by amendments throughout the years, and currently includes six technical annexes: Annex I Regulations for the Prevention of Pollution by Oil; Annex II Regulations for the Control of Pollution by Noxious Liquid Substances in Bulk; Annex III Prevention of Pollution by Harmful Substances Carried by Sea in Packaged Form; Annex IV Prevention of Pollution by Sewage from Ships; Annex V Prevention of Pollution by Garbage from Ships; and Annex VI Prevention of Air Pollution from Ships.
Annex I applies to all oil tankers of 150 g.t. and above, and every other ship of 400 g.t. The regulations relate to the control of discharge of oil originating from machinery spaces, control of discharge of oil originating from cargo spaces, ballast tank arrangements and locations, double hull requirements and SOPEP/SMPEP. Annex I gives requirements for survey and issuance of International Oil Pollution Prevention Certificates (IOPP).
Annex II details the discharge criteria and measures for the control of pollution by noxious liquid substances carried in bulk. The discharge of residues of such substances is allowed only to reception facilities until certain concentrations and conditions are complied with. In any case, no discharge of residues containing noxious substances is permitted within 12 n.m. of the nearest land.
Annex III contains general requirements for the issuing of detailed standards on packing, marking, labelling, documentation, stowage, quantity limitations, exceptions and notifications with regards to harmful substances (as identified as marine pollutants in the International Maritime Dangerous Goods Code (IMDG Code, or which meet the criteria in the appendix of Annex III) carried by sea in packaged form.
Annex IV applies to ships of 400 g.t. and above and ships below 400 g.t. that are certified to carry more than 15 persons. The Annex contains a set of regulations regarding the discharge of sewage into the sea, ships' equipment and systems for the control of sewage discharge and requirements for survey and issuance of International Sewage Pollution Prevention Certificates (ISPP). The Baltic Sea as a special area under Annex IV.
Annex V deals with different types of garbage and specifies the distances from land and the manner in which they may be disposed of.
Annex VI applies to all ships 400 g.t. and above, and to all fixed and floating drilling rigs and other platforms. Annex VI contains regulations regarding ozone depleting substances from refrigerating plants and firefighting equipment, nitrogen oxides (NOx) from diesel engines, sulphur oxides (SOx) from diesel engines, volatile organic compound emissions from cargo tanks of oil tankers, shipboard incineration and fuel oil quality. Annex VI gives requirements for survey and issuance of International Air Pollution Prevention Certificate (IAPP).