Oil spills often result in both immediate and long-term environmental damage. Some of the environmental damage caused by an oil spill can last for decades after the spill occurs.

Here are some of the most notable environmental damages typically caused by oil spills:

Oil Spills Damage Beaches, Marshlands and Fragile Marine Ecosystems
Oil spilled by damaged tankers, pipelines or offshore oil rigs coats everything it touches and becomes an unwelcome but long-term part of every ecosystem it enters.

When an oil slick from a large oil spill reaches the beach, the oil coats and clings to every rock and grain of sand. If the oil washes into coastal marshes, mangrove forests or other wetlands, fibrous plants and grasses absorb the oil, which can damage the plants and make the whole area unsuitable as wildlife habitat.

When some of the oil eventually stops floating on the surface of the water and begins to sink into the marine environment, it can have the same kind of damaging effects on fragile underwater ecosystems, killing or contaminating many fish and smaller organisms that are essential links in the global food chain.

Despite massive clean-up efforts following the Exxon Valdez oil spill in 1989, for example, a 2007 study conducted by the National Oceanic and Atmospheric Administration (NOAA) found that 26, 000 gallons of oil from the Exxon Valdez oil spill was still trapped in the sand along the Alaska shoreline.

via: environment.about.com