The U.S. Environmental Protection Agency's decision Friday to eliminate its scientific research arm drew horrified responses from public health experts and climate advocates, who warned that the Trump administration is targeting the foundation of the department's work to shield Americans from hazardous chemicals, toxic pollution, and drinking water contaminants.

"This is grim news," said Adam Gaffney, an ICU doctor at the Cambridge Health Alliance. "For decades, the EPA's Office of Research and Development has produced the science that underlies the regulations and technologies that protect us from innumerable hazards."

"You can't put a number on the lives that it has saved. Now Trump and Zeldin are killing it," Gaffney added, referring to the president's handpicked EPA administrator.

Since taking charge at the EPA, Lee Zeldin has moved aggressively to implement President Donald Trump's executive orders aimed at gutting the agency's staff and freeing oil and gas corporations from regulatory restraints.

The agency will soon have 12,448 employees, after starting the year with more than 16,000. Staffers at the targeted research office—which had more than 800 employees as of earlier this week—reportedly learned of what one public health expert called "the ultimate Friday night purge" through the EPA's public press release.