Oil is a critical resource for the world. Millions of barrels of oil are shipped from where the oil is taken from the Earth to where it is processed (refined) into substances varying from fuel to plastics. Because the world's demand for crude oil is great, oil must be shipped in large quantities by oceanic tankers, barges on inland waters, and pipelines that run over the land and under the sea. When there is a mistake or accident that causes oil to spill from any of these means of transport, damage to the water, beaches, and economy can be devastating.

Oil (also known as petroleum) is a naturally occurring thick liquid mixture of the elements hydrogen and carbon combined to form chemicals known as hydrocarbons. The oil taken from the ground (or seafloor) is called crude oil. Crude oil is then pumped or shipped to plants...