Using a law passed in 1953 (Section 12a of the Outer-Continental Shelf Lands Act), the still President Obama acted decisively to protect the Arctic from oil exploration. His announcement was joined by Canada's that also protects its Arctic waters from exploration. Canada's decision is subject to review every five years, but administration officials insist the President's decision is "permanent". Undoubtedly the Trump regime will move soon to overturn his executive action. The American Petroleum Institute insisted there is no such thing as a permanent withdrawal of public lands from oil leasing on the continental shelf, and called the decision "short-sighted". Rex Tillerson, CEO of the Earth's biggest oil company, and now the President-elect's choice for Secretary of State will play a large role in attempting to reverse the decision. An NRDC spokesman vowed his organization would legally challenge Trump's effort to reverse the decision to withdraw Arctic waters from oil leasing. Shell's attempt this year to exploit leases it owns in the Chukchi Sea largely failed and the company called off further exploration efforts. An estimated 27 billion barrels of oil and 132 trillion cubic feet of gas remain untapped in the Arctic.