Comment period ends on May 19, 2025
On April 17, 2025, the U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS) issued a proposed rule to rescind the regulatory definition of “harm” under the Endangered Species Act (ESA). This action would remove the current definitions of “harm” from both 50 CFR 17.3 (FWS) and 50 CFR 222.102 (NMFS). If finalized, the proposed rule would significantly narrow a key and long-standing element of ESA interpretation and enforcement. However, state-level protections may fill some of the gap left in the federal regulations.
The Current Definition of “Harm” in the Endangered Species Act
At its core, the ESA prohibits the “take” of endangered and threatened species, defining “take” as “to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any such conduct.”
For decades, federal regulations have interpreted “harm” to include not only direct actions like hunting or trapping, but also “significant habitat modification or degradation which actually kills or injures fish or wildlife by significantly impairing essential behavioral patterns, including breeding, spawning, rearing, migrating, feeding or sheltering.” This interpretation has been a cornerstone of species protection, recognizing that the destruction of habitat can be just as harmful as direct actions against listed species.
The current definition of “harm” was upheld by the U.S. Supreme Court in Babbitt v. Sweet Home Chapter of Communities for a Great Oregon (1995). The Court found that the Secretary of the Interior’s interpretation of “harm” to include habitat modification was a reasonable reading of the ESA under Chevron deference, given the law’s purpose to provide comprehensive protection for endangered and threatened species.
The Proposed Rule
In their proposed rule, FWS and NMFS note that the Chevron doctrine was overruled in Loper Bright Enterprises v. Raimondo (2024). The agencies state that, under the new legal standard, the question is whether the statute itself authorizes the agency's action, not whether the agency's interpretation is reasonable. The agencies argue that the current regulatory definition of “harm” does not match the “single, best meaning” of the statutory text, which they interpret in the proposed rule as limiting “harm” to direct actions that physically injure or kill individual animals or plants—such as hunting, trapping, or shooting—excluding indirect impacts like habitat destruction. Thus, the proposed rule may be an example of how the administration plans to affirmatively wield Loper Bright by rescinding certain regulations previously upheld under Chevron, rather than waiting for those regulations to be challenged and struck down in court.
If finalized as proposed, the rule would remove the definition of “harm” from federal regulations and rely solely on the statutory definition of “take.” The agencies contend that this change is necessary to faithfully execute the law as written and to reduce what they describe as unnecessary regulatory burdens on landowners, businesses, and developers.
The proposed rule would mark a significant departure from 50 years of ESA enforcement. Environmental advocates warn that the change could have devastating consequences, as habitat protection has arguably been the primary focus of ESA implementation over that period. In contrast, some industry groups and some property rights advocates have long pushed for this change, arguing that the current definition of “harm” is overbroad.
The proposed rule is now open for public comment, with stakeholders on all sides expected to weigh in. The deadline for commenting is May 19, 2025.
State-Level Protections
Importantly, even if FWS and NMFS rescind the regulatory definition of “harm” under the federal ESA, state-level protections for endangered species habitats may still apply.
For example, the Massachusetts Endangered Species Act’s implementing regulations, 321 CMR 10.00, define “take” to include “disrupt[ion of] the nesting, breeding, feeding or migratory activity” and expressly state that “[d]isruption of nesting, breeding, feeding or migratory activity may result from, but is not limited to, the modification, degradation or destruction of Habitat.” The state regulations also prohibit unauthorized “alteration of Significant Habitat.”
The New York Endangered Species Regulations, 6 NYCRR Part 182, similarly define “take” to mean “pursuing, shooting, hunting, killing, capturing, trapping, snaring and netting of any species listed as endangered or threatened in this Part, and all lesser acts such as disturbing, harrying or worrying,” and further define “lesser acts” to include “any adverse modification of habitat of any species listed as endangered or threatened.”
Georgia’s regulations on the Protection of Endangered, Threatened, Rare, or Unusual Species, Ga. Comp. R. & Regs. 391-4-10, likewise prohibit “[t]he destruction of the habitat of any protected animal species on public lands.”
Accordingly, any individual or entity who may alter the habitat of an endangered species should be sure to understand applicable state habitat protections, which will continue to apply even if similar federal regulatory protections are rescinded.
