ANCHORAGE, Alaska (AP) — More than 18 million acres of a petroleum reserve in Alaska will be opened to oil and gas drilling under a plan released Thursday by federal officials, who touted it as being key to President Donald Trump’s goal of increasing energy production.

“Today’s action is one more significant step in the process of delivering on his promise,” Interior Secretary David Bernhardt said in a statement.

The Department of Interior released the environmental review for the National Petroleum Reserve-Alaska, which covers an area the size Indiana. The area was set aside by President Warren Harding in 1923 for its potential petroleum value.

The 23-million-acre site on the western North Slope contains about 8.7 billion barrels of oil, according to the U.S. Geological Survey.

Environmentalists decry opening up the reserve, worried about what drilling could do to wildlife such as polar bears and a large caribou herd.

“This plan turns its back on unique and spectacular Arctic wildlife species and sells their key habitat out to the oil industry,” said Nicole Whittington-Evans, Alaska program director for Defenders of Wildlife.

“It gives away critical habitat for imperiled polar bears and vital habitat for caribou and migratory birds to oil companies that will only exacerbate the climate crisis by expanding into a fragile frontier area with new drilling,” she said. “It is bad for the Western Arctic and bad for the planet.”

The U.S. Bureau of Land Management last fall released a draft, holding public meetings across Alaska and a comment period where people could weigh in on four alternatives, including two that would have allowed lease sales on lands designated as special conservation areas under the Obama administration.

The Interior Department cited public comments in advancing a new option that would increase the area open to development leasing by about 7 million acres. The 18.6 million acres total under this preferred plan, or 82% of the reserves subsurface area, will be open to oil and gas drilling, officials said in a release.

In the plan, the Teshepkpuk Lake area would see some stipulations, including limits on when drilling could occur to mitigate impacts on caribou calving and on bird habitats. The lake’s special area designation would allow for geographic boundary changes to account for changing caribou calving patterns.

The plan also calls for ramps and special road pullouts to accommodate subsistence hunters.

“The BLM worked with state, local, tribal, and private sector stakeholders to propose management prescriptions that achieve a balance between conservation stewardship, being a good neighbor, and responsibly developing our natural resources to boost local and national economies,” said Chad Padgett, the state director of BLM Alaska.

Members of Alaska’s all Republican congressional delegation hailed the plan.

“As Alaskans work toward economic recovery, having a robust plan to unlock the potential of one of the most promising areas on the North Slope is a powerful tool,” said U.S. Sen. Lisa Murkowski. “NPR-A holds billions of barrels of oil that will ensure the continued operation of the Trans-Alaska Pipeline System and support good jobs for thousands of Alaskans.”

David Krause with The Wilderness Society said this was no time to dismantle conservation protections for fragile Arctic landscapes.

“Though long expected, the final environmental impact statement is another sad and harmful development in this administration’s shameful race to destroy public lands by auctioning off wild, irreplaceable ecosystems for industrial development,” he said.

The environmental impact statement will be followed by the BLM’s Record of Decision, to be printed in the Federal Register.

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