Prudhoe Bay is the largest oil field in North America, and the eighteenth largest oil field discovered in the world.  Covering 5,000 acres of Alaska's North Slope, Prudhoe Bay includes 3,898 exploratory wells, 170 drilling pads, 500 miles of road, 1,100 miles of pipeline, 5 docks, and 25 production, processing, sea water treatment and power plants.  It is also home to the 5,000 employees who work in the oil fields and live in Prudhoe Bay's town of Deadhorse.  There is an estimated 25 billion barrels of oil in Prudhoe Bay trapped within the Sadlerochit formation, the term for the sandstone and gravel structure found 9,000 feet below ground.  10 billion barrels of oil have already been produced from the bay, while 13 billion barrels are classified as recoverable with current technology.  The oil reserves in Prudhoe Bay were discovered in 1968, and production began June 20, 1977.  Initially 1.5 million barrels of oil and gas liquid were extracted per day; however, production in the bay has slowed down considerably and at the present time an average of 680,000 barrels per day are now produced.  It is from Prudhoe Bay that Alyeska's Trans-Alaskan Pipeline runs to the port of Valdez where it can then be transported by oil tankers to the lower states.  The United States receives 17% of its domestic oil by this process, making Prudhoe Bay a vital contributor to the country's overall oil resources.     Prudhoe Bay is an important issue to consider when reviewing the ANWR controversy, because it provides an example of the consequences and effects of constructing a large oil field in an almost identical environment.  According to the Alaska Department of Environmental Conservation Spill Data Base, there are on average 409 reported spills at Prudhoe Bay. While most of these spills are small, 1.3 million gallons of 40 different substances ranging from acid waste to oil have been spilled between 1996 and 1999.  Studies of diesel spills in the arctic have shown that 28 years after the spilling occurred there is still little vegetation recovery and hydrocarbons remain in the soil, which is evidence that the future of wildlife surrounding oil fields is constantly in danger.  The oil fields disrupt the symbiosis existing in nature; thus, when vegetation is destroyed, the survival of the animals relying on that vegetation as their sustenance is also at risk.  Also, studies conducted by the Alaska Department of Fish and Game show that the female caribou productivity around the North Slope oil fields, including Prudhoe Bay, has declined since oil production began because of the interruption of their calving grounds.  The caribou demonstrate a 3-4 kilometer avoidance of the structures on the oil fields, including roads and pipelines, and the same result is to be expected if the ANWR is developed for oil production.  The Arctic Refuge consists of 19 million acres and the proposed drilling would take up "only" 2000 of these acres. There are two problems with this however: first, the 2000 acres are only the land directly covered by industrial machinery or roads; land underneath raised pipes for example, is not counted in the 2000 acres. Also, land completely enclosed by infrastructure, so long as there is no infrastructure directly above it, is not counted either. Through observing the caribou's interaction with the Prudhoe Bay facilities, it is obvious that they would distance themselves kilometers away from any structure built on the ANWR, thus, not taking into account all the land within this distance greatly underestimates the true effect the proposed oil fields would have.  While the effects of the oil fields in Prudhoe Bay are estimated to extend over an area of 12,000 acres, the actual footprint of production covers over 640,000 acres.

4 Oil field facilities at Prudhoe Bay Oil Development in America's Arctic 1968-2001 5 Trans-Alaskan Pipeline