Oil and gas exploration in a portion of Alaska’s Arctic National Wildlife Refuge (ANWR) will be allowed if the provision passed the by US Senate as part of the Republican tax bill survives in the legislation’s final version and is passed.

That’s not a foregone conclusion as the House tax bill did not include such a provision and House and Senate conferees must now reconcile the two measures and pass a joint bill before it heads to the president’s desk for his signature.

The provision was added by Senator Lisa Murkowski, an Alaska Republican, who has been a long-time supporter of drilling in ANWR. The measure survived the effort led by Senator Maria Cantwell, a Democrat of Washington, to remove it from the Senate bill.

Murkowski said in the statement that passage of the provision “makes this a great day to be an Alaskan.”

Audubon Society CEO David Yarnold labeled the move “shameful,” adding that ANWR “isn’t a bank. Drilling there won’t pay for the tax cuts the Senate just passed.”

Several Republican members of the House oppose drilling in ANWR, as do Democrats, and made their views known to Congressional leaders after the Senate bill passed. But anti-drilling Republicans in the House probably won’t make much of a difference to the chances of the reconciled bill to pass, whereas the absence of Murkowski’s vote for tax reform legislation could put the whole enterprise in jeopardy.