A California-based outdoor clothing retailer may sue to prevent the Trump administration from eliminating any national monuments, its CEO says.

Patagonia, which has criticized governors for their anti-environmentalist stances and funded get-out-the-vote campaigns since 2004, set its sights on President Donald Trump’s latest executive order. Trump told the Department of the Interior on Wednesday to review about two dozen monuments created since 1996 to see whether they exceed the Antiquities Act of 1906.

“A president does not have the authority to rescind a national monument. An attempt to change the boundaries ignores the review process of cultural and historical characteristics and the public input,” Patagonia CEO Rose Marcario said in a statement released Wednesday.

“We’re watching the Trump administration’s actions very closely and preparing to take every step necessary, including legal action, to defend our most treasured public landscapes from coast to coast,” Marcario added.

Trump’s order requires a review of monuments that were created since 1996, that are at least 100,000 acres, or lacked “adequate public outreach and coordination with relevant stakeholders.”

It is not clear whether Katahdin Woods and Waters National Monument, which is east of Baxter State Park, will be reviewed. Katahdin Woods was created by President Barack Obama in August 2016 but is 87,563 acres and was the subject of many public meetings.

The review does not immediately threaten monuments. Experts have said it is uncertain whether a president can undo a monument created by executive order. Trump’s administration has indicated that reversals might be possible under a clause in the law that confines monuments to “the smallest area compatible with proper care and management of the objects to be protected.”

Monument proponent Lucas St. Clair said that Secretary of the Interior Ryan Zinke told him Wednesday night following a board meeting of the Theodore Roosevelt Conservation Partnership that Katahdin Woods would not be reviewed.

“His first question was, ‘How big is it?’ I told him, and he said, ‘Great, it’s not on the list,’” St. Clair said Thursday.

St. Clair serves on the conservation partnership’s board.