The Trump administration on Monday finalized a plan to begin selling leases for companies to drill for oil and gas in the Arctic National Wildlife Refuge, a long off-limits area that environmentalists consider to be one of the wildest places left on Earth.

Interior Secretary David Bernhardt’s “record of decision” authorizing the oil and gas program delivers on a mandate from the 2017 Republican tax cut bill that included a provision allowing energy exploration in a 1.56 million-acre section of the refuge, known as the “1002 area,” where billions of barrels of oil are believed to lie beneath the coastal plain.