An oil spill is a release of crude oil, or other liquid petroleum hydrocarbon, into the environment due to human activity.  On land, oil spills are usually localized and thus their impact can be eliminated relatively easily. In contrast, marine oil spills may result in oil pollution over large areas and present serious environmental hazards.  Oil spills include releases of crude oil from tankers, offshore platforms, drilling rigs and wells, as well as spills of refined petroleum products (such as gasoline, diesel) and their by-products, and heavier fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil.

Large oil spills have the potential to cause serious ecological risk (primarily for sea birds and mammals) and result in long-term environmental disturbances (mainly in coastal zones) and economic impact on coastal activities (especially on fisheries, mariculture, and tourism).