When the Fish and Wildlife Service decided in June to classify all chimpanzees, captive or wild, as endangered, the ruling meant that any biomedical experiment or export of chimps from the United States, whoever owned them, would be subject to a strict permit process under the Endangered Species Act.

Only actions that benefited chimpanzees as a species would be allowed.

In combination with a 2013 decision by the National Institutes of Health to retire most of the several hundred chimpanzees it owned, the change came close to a ban on any medical research on the animals.

It was the culmination of decades of efforts by animal welfare advocates, a growing awareness of how genetically close chimps are to humans, and the declining value of their use in research. Other animals are cheaper to maintain and easier to use, and even the director of the N.I.H. had declared that chimps deserved special consideration.

But for many chimps still in research institutions, a future as happy retirees in sanctuaries has yet to materialize. And how the new rules will play out is an open question. A partial answer is about to come in the first test of the new endangered listing, a permit application now before the Fish and Wildlife Service.