Marine pollution emanating from shipping was first recognised in the 1950s and the international community developed agreements to cope with the mounting volumes of waste materials being discharged into ports, coastal waters and oceans. In 1973, the first comprehensive legal statute, the "International Convention for the Prevention of Pollution from Ships" was developed. This was further amended in 1978 and became known as MARPOL 73/78. Annexes have subsequently been written to include products such as oil, noxious bulk liquids, harmful substances, sewage, and garbage.

Enforcement of these pollution control regulations is not an easy task and its success depends on concerted effort from all participants. the main elements of MARPOL 73/78 require: 

- the provision of adequate reception facilities for oil and chemical residues, garbage and sewage;

- the discharge of any of these wastes is strictly limited and special areas can be nominated where any discharge is prohibited;

- strict ship construction and equipment standards are set to minimise the release of oil and chemicals in case of an accident;

- provision for mandatory ship inspections and surveys to ensure compliance; and

- ship masters to report without delay any incidents involving oil, noxious liquids or harmful substances.

Pollutants are discharged into the ocean from the routine operation of ships (including discharges of sewage and industrial processing wastes and the release of petroleum hydrocarbons from engine exhausts and bilge and ballast waters). Vessel pollution may also result from accidental spills and solid waste disposals. Exhaust emissions into the water from smaller vessels can be a significant source of petroleum hydrocarbons in confined coastal waters.

Atmospheric emissions from ships are recognised as a significant source of global air pollution (Corbett and Fischbeck), yet they are not subject to the same restrictions that are imposed on manufacturing industry or power stations on the land. Seagoing vessels are responsible for an estimated 14% of emissions of nitrogen from fossil fuels and 16% of the emissions of sulphur from petroleum use into the atmosphere.