An oil spill is a release of petroleum into the natural environment. The term oil spill often refers to marine oil spills, when petroleum is released into the sea from damaged tankers. Oil flows on the surface of the sea because it is lighter than water. Petroleum products are very toxic to marine life. Oil spilled in the water often reaches the shore, and severely damages ecosystems for animals and birds in coastal areas. A shoreline habitat may take up to 30 years to recover from a major oil spill. In general, the nature in the Arctic is more vulnerable to oil spills than more southerly ecosystems. Oil spills icy areas are a severe challenge to liquidators. Oil spills most often happen during the loading or transportation of oil