The New York Times reported this afternoon that the Trump administration has put the Environmental Protection Agency into reverse gear. Its leader, Lee Zeldin, was previously a Congressman representing the East End of Long Island, one of the most ecologically fragile places in the U.S.

The Environmental Protection Agency said on Friday that it would eliminate its scientific research arm and begin firing hundreds of chemists, biologists, toxicologists and other scientists, after denying for months that it intended to do so.

The move underscores how the Trump administration is forging ahead with efforts to slash the federal work force and dismantle federal agencies after the Supreme Court allowed these plans to proceed while legal challenges unfold. Government scientists have been particular targets of the administration’s large-scale layoffs.

The decision to dismantle the E.P.A.’s Office of Research and Development had been widely expected since March, when a leaked document that called for eliminating the office was first reported by The New York Times. But until Friday, the Trump administration maintained that no final decisions had been made.

The E.P.A.’s science office provides the independent research that underpins nearly all of the agency’s policies and regulations. It has analyzed the risks of hazardous chemicals, the impact of wildfire smoke on public health and the contamination of drinking water by hydraulic fracturing, or fracking. Its research has often justified stricter environmental rules, prompting pushback from chemical manufacturers and other industries.