The following summarizes the recent history of ANWR and legislative fights in Congress to allow oil exploration there:

1960

One year after Alaska statehood, Eisenhower administration creates the Arctic National Wildlife Range when Congress is unable to agree on a plan. The area covers nearly 9 million acres of coast and mountains adjacent to Canada.

1978/79

Congress designates the Range a federal wilderness area, but also requires evaluation of its oil and gas potential.

1980

After lengthy battle over whether more Alaskan land should be preserved or opened to development, President Jimmy Carter signs law renaming area the Arctic National Wildlife Refuge and more than doubling its size. The new law also directs Interior Dept. to assess oil potential in the refuge's 1.5 million acre coastal plain area.

1987

A federal environmental impact statement says oil drilling in the 1.5 million acre coastal plain would affect the habitat of caribou, musk oxen and other species. The Reagan administration recommends proceeding with an oil and gas leasing program designed to protect the environment.

1989

The Exxon Valdez tanker spill halts efforts to have Congress consider allowing drilling in ANWR.

1991

Senate Energy Committee approves legislation to allow oil and gas leasing in ANWR's coastal plain. Plan is dropped after a filibuster by Senate Democrats.

1995

President Clinton vetoes federal budget bill, which includes language to open ANWR for oil and gas drilling.

1998

US Geological Survey updates its assessment and estimates ANWR's coastal plain contains from 6 billion to 16 billion barrels of technically recoverable oil. US Energy Information Administration estimates it would take up to 12 years to conduct lease sales, permitting and development work, with several more years for ANWR production to peak at more than 800,000 barrels per day.

2001

President Bush unveils energy plan calling for drilling in ANWR. Senate Republicans introduce broad energy bill with incentives for various domestic energy sources, including drilling in ANWR's coastal plain. The House approves a similar bill.

2002

Senate energy bill dies after filibuster over ANWR by coalition of moderate Republicans and Democrats.

March 2003

Senate Republicans insert ANWR drilling provision in annual federal budget resolution. Full Senate kills the provision with a vote of 52-48.

National Research Council, a nonpartisan science group, issues report about harmful environmental impacts on Alaska's North Slope from oil development. The impacts included changes in bowhead whale migration, caribou reproduction and predators that prey on birds.

April 2003

House approves legislation to limit ANWR drilling rigs, production facilities, airstrips and other related development to 2,000 acres of ANWR's coastal plain. Critics say the 2,000 acre limit does not require the land to be contiguous and still poses threat to wildlife habitat.

September 2003

Government Accountability Office, the investigative arm of Congress, reports the Fish and Wildlife Service lacks trained staff and resources to properly monitor the three dozen US wildlife refuges that already allow oil and gas drilling.

November 2004

Senate Republicans say election gains in the chamber give them a good chance of opening ANWR to drilling in the next Congress.

March 10, 2005