The letter, published Monday on the website of activist group Standup for Science, described a climate of political interference and warned that the agency's leadership was eroding public health protections and scientific integrity.

"The Environmental Protection Agency has a zero-tolerance policy for career bureaucrats unlawfully undermining, sabotaging, and undercutting the administration's agenda as voted for by the great people of this country last November," the EPA said in an email to AFP.

More than 200 individuals originally endorsed the statement, though the number placed on administrative leave was 139. The list of names, which initially appeared on the website, has since been removed, and the reason for the numeric discrepancy was not immediately clear.

"The decisions of the current administration frequently contradict the peer-reviewed research and recommendations of Agency experts," said the letter.

"Make no mistake: your actions endanger public health and erode scientific progress -- not only in America -- but around the world."

The letter outlines five key concerns, including the deepening politicization of the EPA, the reversal of initiatives aimed at marginalized communities, and the "dismantling" of the agency's Office of Research and Development.

It further accuses EPA leadership of turning the agency's communications apparatus into a vehicle "to promote misinformation and overtly partisan rhetoric."

Since taking office, Zeldin has led the charge in executing Donald Trump's environmental agenda: gutting climate regulations, ramping up fossil fuel development, and slashing funding for clean energy -- moves that have drawn fierce backlash from scientists and environmental advocates alike.