In an executive order signed on Friday, President Trump directed his secretary of the interior to review current rules on offshore drilling and exploration. This review is likely to result in a relaxation of the strict protections the previous administration put on offshore oil drilling in the Atlantic and in the Arctic.

According to the Washington Post , a review of the rules is likely to “make millions of acres of federal waters eligible for oil and gas leasing.”

At the same time, Trump’s executive order directed the secretary of commerce to cease designating new marine sanctuaries or expanding any that already exist. According to USA Today, Commerce Secretary Wilbur Ross is also “directed to review all designations and expansions of marine monuments or sanctuaries designated under the Antiquities Act within the last 10 years.” The Post says this “includes Hawaii’s Papahanaumokuakea Marine National Monument, which Obama quadrupled in size last year, and the Northeast Canyons and Seamounts off Massachusetts.”

Although these reviews could take some time to complete, they put in motion a bid to favor extraction industries like oil and gas mining. “Today, we’re unleashing American energy and clearing the way for thousands and thousands of high-paying energy jobs,” Trump reportedly told the Associated Press.

President Obama declared US Arctic and Atlantic waters off-limits to drilling in December 2016. He did so with the cooperation of Canadian Prime Minister Justin Trudeau, who also closed off Canadian Arctic waters to new drilling leases. The Obama administration instated this rule using the 1953 Outer Continental Shelf Lands Act, which the administration thought would be more difficult for Trump’s administration to undo than if Obama had simply signed an executive order prohibiting the drilling. The reasoning behind this decision was an interpretation of the 1953 law to mean that the president has the power to withdraw areas of US sea floor from use, while giving no powers to successors to reinstate those areas for use unless Congress goes back and amends the 1953 law.

Still, even if Trump’s executive order does have the intended effect of opening up sea floor to oil and gas drilling, those oil and gas producers may not take him up on his offer. As oil and gas prices fall, drilling in the technically challenging and frigid waters of the Arctic delivers less marginal return than easier drilling. According to CNN Money, “environmental rules didn’t trigger the downturn in the oil industry. Market forces did. The historic shale oil boom created an epic glut of crude, causing prices to crash so low that dozens of companies filed for bankruptcy and some 200,000 workers were laid off.”