The International Convention to prevent pollution from Ships or MARPOL 73/78 is a set of international regulations whose aim is to prevent pollution from ships. It was developed by the International Maritime Organisation, a UN specialised agency.

This convention, endorsed by more than 140 countries, is applied by at least 97% of ships that sail around the world and makes it compulsory for ships to manage their waste properly to avoid spillage into the sea. The convention also sets out the obligatory requirements for Port Authorities to have suitable facilities for the collection, and if applicable, treatment of waste generated on board the ships.

The International Maritime Association estimates than in European waters, through which more than 1,000 million tons of oil circulate, nearly 3,000 illegal oil spillages are recorded per year and that 12% of these come from ships. This is why, as well as a legislation to avoid oil tanker accidents, we need a regulation to avoid the spillage from everyday operations from ships.

The prevention of illegal spillages coming from ships is a great concern and this has resulted in many regulations on a worldwide, European and national level.

The Marpol Convention 73/78 regulates the authorisation of the waste disposal from ships at sea and obliges the signatory States to ensure the availability of proper reception facilities in their ports.

It is made up from six technical Annexes devoted to each type of residue:

Annex I: OilAnnex

Anexo II: Noxious substances carried in bulkAnnex

Anexo III: Harmful substances carried in packaged formAnnex

Anexo IV: SewageAnnex

Anexo V: Solid wasteAnnex

Anexo VI: Air pollution

Annex I, which governs the discharge of oil waste, has been in force since 2nd October 1983 and has been amended on many occasions to suit the needs of each given moment. Three types of oil waste generated by ships are distinguished within this annex:

Type A: crude oil waste and ballast water polluted with crude oil.

Type B: oil waste and ballast water contaminated by oil products that differ from crude oil and with a density of less than or equal to 1.

Type C: waste engine room bilges or fuel purification equipment and engine oils.