U.S. Finalizes Rule Narrowing 'Harm' Definition Under Endangered Species Act

The Trump administration on Friday finalized a rule removing the Endangered Species Act’s long-standing regulatory definition of “harm,” narrowing how the government can use the law to police habitat destruction that affects endangered and threatened wildlife.

The change is significant because the old definition had allowed federal agencies to treat some habitat destruction as unlawful when it actually killed or injured protected animals by disrupting essential behavior such as breeding, feeding or sheltering. By rescinding that definition, the administration is removing a key regulatory basis for treating habitat modification as a prohibited “take” under the law.

The rule was finalized July 10 by the U.S. Fish and Wildlife Service and the National Marine Fisheries Service, the two agencies that implement the Endangered Species Act for most listed species. The agencies said they were returning to what they see as the statute’s best reading rather than keeping a broader interpretation adopted in regulation decades ago. Interior Secretary Doug Burgum backed the move, saying, “For years, federal agencies abused the ESA to obstruct lawful land use and burden American families and businesses.”

Under the Endangered Species Act, it is illegal to “take” endangered wildlife, and the statute says “take” includes “harm” along with other acts. For decades, agency regulations defined harm to include “significant habitat modification or degradation” when it actually kills or injures wildlife. That interpretation has shaped how the government enforces the law, reviews federal actions and issues permits for incidental take tied to development and other activities.

In practical terms, the rollback could affect how agencies handle projects involving land and water use, including logging, mining, oil and gas development, infrastructure work and water projects. The prior definition gave regulators a clearer path to conclude that destroying or degrading habitat could violate the law if it led to the death or injury of protected species. Without that regulatory language, the government is taking a narrower view of when habitat damage can count as illegal harm.

The legal backdrop is important. In 1995, the U.S. Supreme Court, in Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, upheld the Fish and Wildlife Service’s interpretation that harm under the Endangered Species Act can include habitat modification that actually kills or injures wildlife. More recently, administration officials have tied the rollback to the Supreme Court’s 2024 Loper Bright decision, which ended Chevron deference, the doctrine under which courts often deferred to reasonable agency interpretations of ambiguous statutes.

That means this is not simply a technical wording change. It goes to a basic question at the center of endangered-species protection: whether habitat destruction can be treated as illegal harm when it causes real injury or death to protected wildlife. The answer affects not just enforcement cases, but also the consultations and permitting decisions that shape how projects move forward.

The rule was proposed April 17, 2025, and went through a public comment process before being finalized. Environmental groups and scientists argued the rollback would weaken habitat protections for listed species, while industry groups and some state and local officials supported it as a property-rights and permitting reform measure. With decades of Endangered Species Act practice built around the broader definition, the change is poised to become a major legal and conservation flashpoint.