Rescission Of ESA “Harm” Definition Leaves OIRA

On July 7, 2026, the Office of Information and Regulatory Affairs (OIRA) completed its review of final rules to rescind the regulatory definition of “harm” under the Endangered Species Act (ESA). The U.S. Fish and Wildlife Service and National Marine Fisheries Service (Services) jointly proposed to rescind their respective definitions of “harm” in April 2025 (Proposed Rule) and received more than 350,000 comments with respect to their proposed actions.  

As we previously reported, ESA section 9 prohibits “take” of species listed as endangered, which is defined as, among other things, to “harm” such species. The Services’ respective definitions of “harm” have long been the primary mechanism by which the agencies regulate activities that modify ESA-listed species’ habitats.

In the preamble to the Proposed Rule, the Services indicated they did not intend to promulgate replacement definitions and that the agencies believed that the best interpretation of the ESA’s use of the term “harm” is that it requires “an affirmative act…directed immediately and intentionally against a particular animal” rather than “an act or omission that indirectly and accidentally causes injury to a population of animals.”

Now that they have left OIRA, the Services’ final rules rescinding their respective “harm” definitions could be published in the Federal Register and take effect at any time.