Ninety per cent of global trade is conducted by shipping, which is considered to be the most environmentally friendly form of transport, taking into account its productive value. Shipping contributes to a limited extent to marine pollution from human activities, in particular when compared to pollution from land-based sources (or even dumping). Protection of the environment was not the International Maritime Organization’s (hereinafter the IMO) original mandate. Its main interest was maritime safety. However, in 1954 the IMO became the depository of the first 1954 Convention for the Prevention of Pollution from Oil (hereinafter the OILPOL, see further below). Since then the protection of the marine environment has become one of the most important activities of the IMO. Among fifty-one treaty instruments the IMO has adopted so far, twenty-one are directly environment-related (twenty-three if we include the Salvage and Wreck Removal Conventions). The Marine Environment Protection Committee is the IMO’s technical body in charge of marine pollution related matters (it is aided in its work by a number of Sub-Committees).
The precursor of the International Convention on the Prevention of Pollution from Ships (hereinafter the MARPOL) was the OILPOL. This Convention only relates to pollution caused by tankers during their routine operations such as the washing of cargo tanks and dumping of resultant oily water in the ocean. The OILPOL regulated the amount of oily water which could be discharged in the oceans, the places it could be dumped, and encouraged the Parties to install reception facilities where oily water could be discharged. This Convention also introduced special areas (very sensitive) where dumping of oily residues were prohibited. It was amended several times, firstly in 1962 when the limits of special areas were extended. The next fundamental amendment of the OILPOL was effected in 1969 after the Torrey Canyon incident (see further below). A procedure developed by the oil industry and known as ‘load-on-top’ (LOT) was introduced to save oil and reduce pollution. Under this mechanism washings resulting from tank cleaning are pumped into a special tank. During the voyage back to the loading terminal the oil and water separate. The water at the bottom of the tank is pumped overboard, and at the terminal oil is pumped onto the oil left in the tank.
Another amendment was the downsizing of tanks after 1972 so that, in case of damage to the vessel, only a limited amount of oil could enter the sea. The LOT system failed expectations of producing environmental benefits, mostly due to difficulties in its operation and the lack of skilled crews as well as due to unscrupulous crews which circumvented LOT and simply discharged contaminated dirty ballast water.
At the same time, several factors (eg the exponential growth in the maritime transport of oil, the size of tankers, the increasing amount of chemicals being carried at sea, and increasing concern for environmental issues in general), resulted in an opinion expressed by many States that the OILPOL was no longer adequate, despite the various amendments which had been adopted.
One of the factors which contributed to the adoption of the MARPOL was the above-mentioned Torrey Canyon incident. In 1967, the Torrey Canyon ran aground while entering the English Channel and spilled her entire cargo of 120,000 tons of crude oil into the sea. It was the most serious oil pollution incident ever recorded up to that time. This incident raised questions about measures existing at that time to prevent oil pollution from ships and revealed drawbacks of the system for compensation resulting from accidents at sea. In order to accommodate these various changes and occurrences, in 1969 the IMO Assembly decided to convene an international conference to adopt a completely new convention, incorporating the regulations contained in the amended OILPOL Convention. In order to extend the mandate of the Sub-Committee on Oil Pollution, it was renamed the Sub-Committee on Marine Pollution, and finally became the Marine Environment Protection Committee (hereinafter the MEPC) in order to deal with all matters relating to marine pollution.