FACTBOX-Key Facts About ANWR's Land, Oil, Wildlife
The drilling measure, attached to the Senate's version of a federal government budget resolution, still faces opposition from Democrats and several legislative hurdles before it could become law.
The following are key facts about ANWR:
Encompasses 19.6 million acres in northeastern Alaska that includes the Brooks Mountain Range with peaks over 9,000 feet high, lakes, rivers and a rock mesa. Within the refuge, 8 million acres are designated as federal wilderness.
The entire refuge lies north of the Arctic Circle and is about the size of the state of South Carolina.
About 90,000 acres within ANWR and adjacent to its coastal plain is owned by the Kaktovik Inupiat Corp., a native tribe of about 220 residents.
Home to 45 types of land and marine mammals including the bowhead whale, polar and grizzly bears and moose. ANWR's coastal plain is used as a nursery by caribou in the summer months and by polar bears in the autumn.
Some 180 species of birds have been observed in the refuge, including migratory birds such as Dunlins from China, Buff-breasted Sandpipers from Argentina and Tundra Swans from Maryland.
The Interior Department and the US Geological Survey believe the best geologic prospects for a major oil discovery are in ANWR's coastal plain, located about 100 miles east of Alaska's Prudhoe Bay.
The government estimates up to 16 billion barrels of oil in ANWR are technically recoverable, although much of that would be too expensive to produce at today's prices. With prices were at or above $35 a barrel, energy companies could economically recover an estimated 6 billion barrels of oil from ANWR.
The oil estimates are based on seismic surveys, aerial surveys and geological investigations. No exploratory drilling has been allowed in ANWR except for one well in the winter of 1984-85 on land owned by the Kaktovik Inupiat Corp.
If leasing is permitted on ANWR and commercial exploration and development begins, it could take up to 12 years before any oil reaches the market, according to government and industry estimates.