The MARPOL Convention is an international agreement which covers, and has done much to reduce, pollution of the marine environment by ships. It was adopted by the International Maritime Organization (IMO) in 1973, and was modified and expanded in 1978, resulting in the designation MARPOL 73/78. The Convention consists of a main agreement and several annexes. The main agreement sets forth the general obligations under the Convention and defines its scope of application, whereas the technical annexes contain clear and detailed provisions on dealing with sewage, garbage, oil and noxious/ harmful substances on ships. Annex 1, which deals with oil, entered into force in October 1983. Among other things, it requires the disposal of waste oil in approved shore facilities and makes double hulls mandatory for tankers. In accordance with Annex 1, crews must also keep an oil record book, in which the total quantity of oil and oily water on board and the total content and identity of tanks must be recorded.