On May 1, 2025, the staff members at the U.S. National Science Foundation (NSF) were told to “stop awarding all funding actions until further notice,” according to an email seen by Nature.

An NSF staff member says that although good science can still be funded, the policy has the potential to be “Orwellian overreach”. Another staff member says, “They are butchering the gold standard merit review process that was established at NSF over decades”. One program officer says they are resigning because of the policy. Nature spoke with five NSF staffers for this story, all on the condition of anonymity because they are not authorized to speak to the media.

The changes are hitting an agency already in crisis. In the past two weeks, the NSF has terminated roughly 1,040 grants that would have awarded US$739 million to researchers and their institutions. The agency’s director, Sethuraman Panchanathan, resigned last month.

Uncertainty is also being felt by scientists outside the agency. Colin Carlson, an expert in disease emergence at Yale University in New Haven, Connecticut, leads an initiative to predict viruses that pose pandemic threats. The project, which involves roughly 50 researchers across multiple universities, is funded by a $US12.5 million NSF grant. The project’s latest round of funding was approved, but Carlson worries about subsequent rounds, and the fate of other researchers. Unless it is lifted, the freeze “is going to destroy people’s labs,” Carlson says.

Funding for the NSF, as for all other federal agencies, is set by the US Congress. To date, the agency has received only about one-quarter of the funding that Congress appropriated to it for the current fiscal year, which ends on 30 September.

Update: The US National Science Foundation (NSF) terminated roughly 380 grants on Friday, 2 May, an NSF staff member told Nature. That raises the total number of terminated grants to approximately 1,425.