An oil spill (or slick) is the intentional or unintentional release of oil (generally, petroleum) into the natural environment as a result of human activity. The term often refers to marine oil spills where oil is released into the ocean or coastal waters. Oil can refer to many different materials, including crude oil, refined petroleum products or by-products, oily refuse, oil mixed in waste, or oily ballast. Oil is also released into the environment from natural geologic seeps on the seafloor, as along the California coastline.

The fate, behavior, and environmental effects of spilled oil can vary depending upon the type and amount of material spilled. In general, lighter refined petroleum products such as diesel and gasoline are more likely to mix in the water column and are more toxic to marine life, but tend to evaporate relatively quickly and do not persist long in the environment. Heavier crude or fuel oil, while of less immediate toxicity, can remain on the water surface or stranded on the shoreline for much longer. Oil from the Exxon Valdez and Gulf War oil spills, while weathering over time, has persisted along the shoreline for years after the spill.

With vast numbers living and depending on coastal areas for fishing and tourism throughout the world the consequences are evermore frightening. Such possibilities have caused outcries for oil companies, ship owners, and shipbuilders to share the responsibility of preventing such a disaster.

While ships today are more equipped than ever before the risks are far greater due to the ever increasing number of ships. One step in preventing further oil disasters is through designing boats in a manner that will minimize the chances of a spill. This is being done as ships today are increasingly requiring double hulls due to environmental regulation. Another step in mitigating the possible effects of an oil spill is through being able to contain and effectively treat spilt oil. A new vital step being developed in preventing oil damage is through installations of systems made for Fast Oil Recovery (FOR) of oil from wrecked ships. New innovations for mitigating possible oil spill consequence have met, however, an uncompromising shipping industry which historically has shown only to comply environmentally when either required or economically beneficial.