Congress required the refuge be opened to development in a 2017 tax law.

The Trump administration will allow oil and gas drilling in the Arctic National Wildlife Refuge for the first time after decades of controversy and tension over concern drilling for an undetermined amount of oil would massively disrupt the pristine wilderness and tribes in the area.

Interior Secretary David Bernhardt said Monday his department is opening 1,563,500 acres on the coast of the refuge available for oil and gas leasing or exploratory activity, with some restrictions to protect wildlife in the area.

The refuge covers 19.64 million acres in northeastern Alaska and is managed by the U.S. Fish and Wildlife Service to protect wildlife in its natural habitat, protect the land and water, and maintain resources needed for local residents and tribes that rely on it.

Future oil and gas activities resulting from the decision are expected to impact greenhouse gas emissions, water quality, wildlife population and migration patterns, and impacts of increased human activity in the area, according to the environmental impact statement.

Bernhardt said he was careful not to make decisions around the timing of the election – in part because Congress already mandated ANWR be opened to oil and gas activity in the Tax Cuts and Jobs Act signed into law in 2017.

“Congress signed legislation that is clear in their direction and expectation to us. And I am very confident that I will move forward expeditiously and I’m not really driven by the political dynamics I wanted to ensure that I deliberated carefully on what I included in the [record of decision],” he said.

“I’ve done that and I feel comfortable about that, and I feel comfortable that we certainly can move forward. Quite promptly after after this decision is rendered.”

In an interview on “Fox and Friends,” President Donald Trump did not specifically address the plan but called it a “big deal,” and said he’s been very good to Alaska and that he’s pro-energy. He also referenced decisions he said would expand lobster fishing in Maine, saying he should win the state, and a bill he recently signed to establish a permanent fund to maintain national parks.

“I hate to say it, in theory I should go down as a great environmental president,” Trump said in a phone interview Monday morning,

Bernhardt said even if a new administration wanted to reverse this decision they would also be bound by the 2017 law, giving the department even less discretion in how to move forward than usual.

“Here’s the reality, Congress has mandated these lease sales. And so they have to go forward in some regard they can’t simply unduly delay,” he said on a call with reporters.

“So that that is that is a reality the Congress created, and really, you know, absent a change in the law, the question of whether or not there will be a program in Anwar has really been answered the issue now is, is how do we go about it.”

An unique part of the decision compared to other areas where oil and gas activity has been allowed on public lands is that in this case the Interior Department had less of a choice, Congress mandated that leases for oil and gas drilling in ANWR had to be sold in the Tax Cuts and Jobs Act signed into law in 2017.

Alaska GOP Gov. Michael Dunleavy and lawmakers like Republican Sens. Dan Sullivan and Lisa Murkowski praised the decision in a press release, saying it will help the state’s economy

But Interior’s decision still determines the conditions of those leases and environmental groups argue oil and gas activity in ANWR will cause too much disruption to wildlife in the area, including caribou that are an important source of food and an integral part of the culture for the Gwich’in Indian Nation.

Organizations like the Alaska Wilderness League and Center for Biological Diversity say they will continue to fight the decision, including by pressuring companies and banks against investing in the area.

“Our climate is in crisis, oil prices have cratered, and major banks are pulling out of Arctic financing right and left. And yet the Trump administration continues its race to liquidate our nation’s last great wilderness, putting at risk the indigenous peoples and iconic wildlife that depend on it,” Alaska Wilderness League Executive Director Adam Kolton said in a statement.

“The American people will not stand for the liquidation of our nation’s most iconic wilderness We will continue to fight this at every turn, in the courts, in Congress and in the corporate boardrooms. Any oil company that would seek to drill in the Arctic Refuge will face enormous reputational, legal and financial risks,” he added.

Bernhardt said details have not been finalized yet for when oil and gas leases will be made available but they could see a sale by the end of the year. The department estimates oil and gas production in the area could begin in about 8 years and continue for an estimated 50 years under the decision.