By: Kevin Kaufhold

Fossil fuels are natural resources containing hydrocarbons. These fuels are formed in the Earth over millions of years and produce carbon dioxide when burnt.

Coal is a solid fossil fuel formed over millions of years by decay of land vegetation. When layers are compacted and heated over time, deposits are turned into coal.

Oil is a liquid fossil fuel that is formed from the remains of marine microorganisms that were left on the bottom of the sea floor. Oil is the most widely used fossil fuel.

Natural gas is a gaseous fossil fuel that is abundant and clean compared to coal and oil. Like oil, it is formed from the remains of marine microorganisms. It is a relatively new type of energy source.

A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value.

An oil refinery is an industrial process plant where crude oil is processed and refined into more useful petroleum products. Oil refineries are usually large industrial complexes with extensive piping running throughout. The crude oil feedstock has typically been processed by an oil production plant. There is usually an oil depot at or near an oil refinery for storage of bulk liquid products.

The Exxon Valdez oil spill happened in Prince William Sound, Alaska, on March 24, 1989. The Exxon Valdez, an oil tanker bound for Long Beach, California, hit Prince William Sound’s Bligh Reef and spilled an estimated minimum 10.8 million US gallons of crude oil. It is considered to be one of the most devastating human-caused environmental disasters ever to occur in history. As significant as the Valdez spill was it ranks well down on the list of the world's largest oil spills in terms of volume released. Prince William Sound's location made government and industry response efforts difficult and severely taxed existing plans for response. The region is a habitat for salmon, sea otters, seals and seabirds. The oil, originally extracted at the Prudhoe Bay oil field, eventually covered 1,300 miles of coastline and 11,000 square miles of ocean.

Deepwater Horizon was an ultra-deepwater, dynamically positioned, semi-submersible offshore drilling rig which sank on April 22, 2010, causing the Deepwater Horizon oil spill. The spill was the result of an explosion two days earlier where 11 crewmen died. Deepwater Horizon was built in 2001 in South Korea. It was registered in Majuro , Marshall Islands . In September 2009, the rig drilled the deepest oil well in history at a vertical depth of 35,050 feet and measured depth of 35,055 feet. The oil spill may become one of the worst environmental disasters in United States history.