WASHINGTON — Wild chimpanzees have been protected under the Endangered Species Act for nearly a quarter century, but not captive chimps. Without that oversight, they have been held in pens, bought and sold for research, and poked, prodded and injected with potions to find cures that might benefit humans.

The U.S. Fish and Wildlife Service changed that Friday by announcing new rules that pull captive chimpanzees under the umbrella of federal protection. The designation put an end to the service’s only “split listing” under the Endangered Species Act in its history, designed in 1990 to allow the National Institutes of Health to fund medical experiments using captive chimps.

Under rules that go into effect in September, importing and exporting chimpanzees across U.S. borders, and across state borders, for biomedical research will require federal permits issued by Fish and Wildlife. When the new rules were proposed two years ago following a request by primate specialist Jane Goodall and the Humane Society of the United States, agency Director Dan Ashe called the earlier decision to list wild chimps as endangered and captive chimps as threatened, with less protection, “flawed,” and said the proposal “would correct this inconsistency.”

Ashe said the new rule is a clear message that, contrary to popular belief, the survival of all chimps is threatened. More than a million have disappeared from the wild since the beginning of the 20th century, according to estimates by the International Union for the Conservation of Nature and Natural Resources.

Although the rule hurts an industry that trades chimps as exotic pets for entertainment uses, such as circuses and movies, it hits medical research in the United States the hardest. The U.S. is the only developed nation that continues to use apes for research, at the insistence of the NIH. European nations banned the practice years ago, though they continue to use large numbers of rhesus macaques and spider monkeys for tests.