The last 50 chimpanzees used in biomedical research funded by the National Institutes of Health (NIH) will be released to the national chimpanzee sanctuary on the order of NIH director Francis Collins. The decision effectively puts an end to government-funded biomedical research on our primate relatives in the United States.

“It is clear that we’ve reached a tipping point,” Dr. Collins said in a statement. “I have reassessed the need to maintain chimpanzees for biomedical research and decided that effective immediately, NIH will no longer maintain a colony of 50 chimpanzees for future research.”

These 50 chimps have been the only ones in use in NIH-funded biomedical research since 2013, when the NIH decided there was little justification for including chimps in such studies because “new scientific methods and technologies have rendered their use in research largely unnecessary,” Collins explained then. As a result, the NIH subsequently released more than 300 chimps into retirement.

The current decision to let the final troop retire comes just a few months after the U.S. Fish and Wildlife Service classified all chimpanzees—both wild and captive—as endangered under the Endangered Species Act. (Before that, only wild chimpanzees were considered endangered.) This designation triggered a new protocol that required researchers working in private laboratories to obtain a permit showing how harmful or invasive research would benefit wild chimp populations. Those permits were also subject to public comment. As of September 14, when the new rules took effect, no one has applied for one, according to the NIH.  

That’s significant, because there are an estimated 700 chimpanzees being used in private research facilities in the U.S., says The Humane Society, one of the organizations that filed the legal petition that led to the new endangered species classification.

Where will the chimps go? To Chimp Haven, the national chimpanzee sanctuary in Keithville, Lousiana, which has provided a refuge for retired research chimps since 2002. They’ll relocate the chimps to the Bayou State “as space is available and on a timescale that will allow for optimal transition of each individual chimpanzee with careful consideration of their welfare, including their health and social grouping,” according to Collins’ statement.  

This decision only applies to chimpanzees, Collins is careful to note. “Research with other non-human primates will continue to be valued, supported, and conducted by the NIH,” he said.