Contractors working for the Trump administration are blowing apart a mountain on protected lands in southern Arizona to make way for the president’s border wall. The blasting is happening on the Organ Pipe Cactus National Monument, a tract of Sonoran Desert wilderness long celebrated as one of the nation’s great ecological treasures, that holds profound spiritual significance to multiple Native American groups.

In a statement to The Intercept, U.S. Customs and Border Protection confirmed that the blasting began this week and will continue through the end of the month. “The construction contractor has begun controlled blasting, in preparation for new border wall system construction, within the Roosevelt Reservation at Monument Mountain in the U.S. Border Patrol’s Tucson Sector,” the statement said, referring to an area also known as Monument Hill. “The controlled blasting is targeted and will continue intermittently for the rest of the month.”

The agency added that it “will continue to have an environmental monitor present during these activities as well as on-going clearing activities.”

Rep. Raúl Grijalva, an Arizona Democrat and chair of the House Committee on Natural Resources, told The Intercept that he has zero faith that the Department of Homeland Security’s “environmental monitor will do anything to avoid, mitigate, or even point out some of the sacrilegious things that are occurring and will continue to occur, given the way they’re proceeding.”

Grijalva’s blunt assessment is based on a visit he made to Organ Pipe last month, alongside archaeologists and leaders of the Tohono O’odham Nation, whose ancestral homelands and sacred burial sites are in the crosshairs of President Donald Trump’s border wall expansion. One of those burial sites lies just beyond the westward advance of the border wall, Grijalva explained. “It’s right in the path,” he said, meaning that “the one indignation of the blasting on the hill is shortly to follow with other indignations and disrespect.” According to Grijalava, “DHS had mentioned to the tribes that they would back off on developing the hill, but the work is still being done.”

The agency has consistently failed in its legal obligation to meaningfully consult with tribal stakeholders in southern Arizona, Grijalva said. The blasting that’s happening now, he added, “is just the crudest indication of what’s going on.”

Celebrated as “a pristine example of an intact Sonoran Desert ecosystem,” Organ Pipe was designated as a UNESCO International Biosphere Reserve in 1976. Even before the explosions began, the construction there was already one of Trump’s most controversial border wall projects, unfolding on the homelands of the Tohono O’odham and in areas that are ostensibly safeguarded by the strictest public-land designations on the books.

Neither factor has stopped contractors from drilling into the ground and draining water from a rare desert aquifer in order to mix concrete to support a towering, 30-foot barrier along the U.S.-Mexico divide. In working to fulfill the president’s chief campaign promise, construction crews on Organ Pipe have uprooted saguaro cacti, slicing the iconic plants into chunks and bulldozed a wide roadway to make room for trucks, cranes, and other construction vehicles.

With the wall in place, and its floodlights illuminating the area through the night, the migration of several rare desert animal species is expected to come to an end. The construction is particularly threatening to Quitobaquito Springs, the only naturally occurring source of fresh water for miles around. The desert oasis was once inhabited by the Hia Ced O’odham — a smaller, though distinct O’odham tribe — and remains a monumentally important spiritual site for the O’odham people to this day.

“A historically significant area is going to be changed irreparably,” Grijalva said. “You’re never going to be able to put it back together.”

The expansion of the border wall under Trump has been made possible, in part, by a post-9/11 piece of legislation known as the Real ID Act, which grants DHS sweeping authority to waive existing laws in order to construct border barriers. The Trump administration has used the act to waive dozens of laws — from the Environmental Protection Act to the Endangered Species Act — in order to push through new border wall construction projects.

In Arizona, the administration’s efforts have been bolstered by the fact that federal lands, rather than private property, comprise much of the border. Following his visit to Organ Pipe last month, Grijalva, sent a letter to Acting DHS Secretary Chad Wolf, expressing “serious concerns” that the department was “not respecting tribal lands and sacred sites as they proceed with border wall plans and construction.”

Accompanying Grijalva’s complaint was a letter from Ned Norris Jr., chair of the Tohono O’odham Nation, to the U.S. Border Patrol, in which Norris reported that border wall construction on Organ Pipe had already “resulted in the inadvertent discovery of human remains” near Quitobaquito Springs.

“It’s been really frustrating,” Grijalva said. “You would think that in a situation like this, that involves human remains, burial sites, bone fragments that are traced and dated a thousand years or more back, that there would be some sensitivity, for lack of a better word, on the part of DHS and the administration. There is none.”

The entire episode is deeply political, Grijalva said, with the Trump administration clearly bent on completing as many new miles of wall construction as possible ahead of the 2020 election. “What’s particularly frightening right now is that Trump has weaponized DHS, politically weaponized them,” Grijalva explained. “And so right now, it’s about satisfying that political agenda.”

“The consequence of that, the intended consequence of that, is situations like this,” Grijalva said. “Situations like South Texas. The flooding of public lands. The loss of habitat. The list goes on.”

With the realities of border wall expansion in southern Arizona coming into grim focus over the past few months, advocates on the ground have worried that construction on Organ Pipe might involve explosives. Though the monument is a desert, it is hardly flat. Just west of Arizona’s Lukeville port of entry from Mexico is Monument Hill, a rolling mound of earth that is not conducive to the kind of border wall construction that has rapidly unfolded elsewhere in the area.

Laiken Jordahl, borderlands campaigner for the Center for Biological Diversity, first got word the blasting was happening on Tuesday. He drove down from Tucson the next morning to investigate. A former National Park Service employee at Organ Pipe, Jordahl has consistently documented the monument’s destruction. At a gas station on his way to Organ Pipe on Wednesday, Jordahl spotted a construction vehicle adorned in yellow cautionary signs that read: “Explosives.”

Speaking to The Intercept from down the road, with the border wall construction in sight at a distance, Jordahl said he could not hear active blasting, though it was evident that crews on the ground were clearing a significant patch of land.

“They’ve completely decimated Monument Hill,” he said.

Jordahl snapped several photos showing a broad swath of overturned earth on the hill’s face, which he said was not present just a couple weeks earlier. He crossed the border into Mexico and took more photos. With spotty cell service, he tapped out a statement on the latest phase of borderlands destruction in a text message. “The Department of Homeland security is exploding a mountain on O’odham land and UNESCO biosphere reserve to build Trump’s wall. Draining precious groundwater, bulldozing ancient saguaros and plowing over burial grounds isn’t enough,” he wrote. “Now they’re literally dynamiting a mountain in protected wilderness lands.”

“Nothing is sacred to them, no amount of destruction too grand,” he went on to say. “We’re living a nightmare down here in the borderlands.”