(WASHINGTON) – U.S. President Donald Trump will sign an executive order on Wednesday to identify national monuments that can be rescinded or resized – part of a push to open up more federal lands to drilling, mining and other development.

The move comes as Trump seeks to reverse a slew of environmental protections ushered in by former President Barack Obama that he said were hobbling economic growth – an agenda that is cheering industry but enraging conservationists.

Interior Secretary Ryan Zinke told reporters late Tuesday that Trump’s order would require him to conduct the review of around 30 national monuments created over the past two decades, and recommend which designations should be lifted or altered.

Zinke said he would seek local feedback before making his recommendations, and added any move by Trump to ultimately reverse a monument designation could be tricky.

“I am not going to predispose what the outcome is going to be,” Zinke said. On rescinding or altering a national monument designation, Zinke said: “It is untested, as you know, whether the president can do that.”

President Woodrow Wilson reduced the size of Washington state’s Mount Olympus National Monument in 1915, arguing there was an urgent need for timber at the time, one of the few examples of national monuments being changed.

The monuments covered by the review will range from the Grand Staircase in Utah created by President Bill Clinton in 1996 to the Bears Ears monuments created by President Barack Obama in December 2016 in the same state, covering millions of acres of land overlying minerals, oil and gas.

Obama’s administration created the Bears Ears monument arguing that it would protect the cultural legacy of Native American tribes and preserve “scenic and historic landscapes.” But Utah’s governor and the state’s congressional delegation opposed the designation, saying it went against the wishes of citizens eager for development.

The area lies near where EOG Resources – a Texas-based company – had been approved to drill.

Zinke said the broader aim of the order is to give states more input in monument designations. A summary of the order said past administrations “overused” the Antiquities Act that allows presidents to create monuments.

Conservation and tribal groups slammed the order.

“With this review, the Trump Administration is walking into a legal, political and moral minefield,” said Kate Kelly, public lands director for the Center for American Progress.

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