It is lighter than water. Oils may be obtained from animal, mineral or vegetable sources. Petroleum and petroleum products can cause oil spills. Oil spills on land are from oil wells, oil transport trucks and pipelines. Ocean sited oil rigs, oil tankers and oil fueled vessels are the cause of water or ocean spills.
Petroleum dissolves the protective waxes in bird feathers.
From freezing, oil coated birds die. The same thing happens with furred ocean mammals such as the otter. Shellfish, clams and oysters take in oil- impregnated water and die. The Coast Guard that nearly one hundred thousand oil spills occur in the ocean each year. Minor oil spills amount to less than one hundred thousand gallons.