The U.S. Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS) (collectively referred to as the “Agencies”) proposed on April 17, 2025, to remove the definition of “harm” under their respective regulations promulgated pursuant to the Endangered Species Act (ESA) (the “ESA Regulations”).
The comment period for this proposed rulemaking closed on May 19, 2025, generating approximately 357,500 comments submitted to the Agencies. The Agencies took this action after determining that the current definition of “harm,” which includes habitat modification degradation, goes beyond and, therefore, contradicts the “well-established, centuries-old understanding of ‘take’ as meaning to kill or capture a wild animal.” The Agencies found support for this action as well in the United States Supreme Court’s recent decision in Loper Bright v. Raimondo, 603 U.S. 369, 400, 144 S. Ct. 2244, 2266 (2024).
“Take” under the Endangered Species Act
The ESA prohibits the “take” of endangered species.16 U.S.C. 1538(a)(1)(B)-(C). The ESA defines “take” to means “harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any such conduct.” 16 U.S.C. 1532(19). The term “harm” used in this definition is not defined by the ESA itself, but it is defined in the ESA regulations as “an act which actually kills or injures wildlife,” such as “significant habitat modification or degradation where it actually kills or injures wildlife by significantly impairing essential behavioral patterns, including breeding, feeding or sheltering.” 50 CFR 17.3 “Harm.”
In the Wake of Loper Bright
Loper Bright overturned long-standing doctrine established in the Court’s decision in Chevron, U.S.A., Inc. v. NRDC, Inc., 467 U.S. 837, 104 S. Ct. 2778 (1984) by which federal courts granted deference to an agency’s interpretation of ambiguous statutory language if that interpretation could be found to be a reasonable one. The Agencies stress that the Supreme Court relied upon Chevron when it upheld the “harm” definition in Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, 515 U.S. 687, 115 S. Ct. 2407 (1995). The Court in Babbitt stated the central question of the case was whether the Agencies exceeded their authority under the ESA by promulgating a regulation that included habitat modification in the definition of “harm.” Babbitt, 515 U.S. at 690. The challengers in that case argued then the Secretary on the Interior had exceeded his authority and that the “harm” definition should have been limited to “direct applications of force against protected species.” Id. at 697. Nonetheless, the Babbitt Supreme Court determined the Secretary of the Interior had not exceeded his authority under the ESA, finding that the inclusion of the definition of “harm” was a reasonable interpretation of ambiguous ESA statutory language consistent with the Chevon doctrine. Accordingly, it upheld the inclusion of "significant habitat modification or degradation where it actually kills or injures wildlife" in the definition of “harm.” Id. at 708.
Agencies’ Rational for Removal of the “Harm” Definition
The Agencies acknowledge in the proposed rule that the Supreme Court’s holding in Babbitt has validated the “harm” definition for thirty years but stress that the overturning of Chevron compels reassessment of the definition. The Agencies note the Loper Bright opinion clarified that the proper questions to ask on review of an agency regulation when resolving such ambiguities are “whether the statute authorizes the challenged agency action,” and if the regulation matches the single, best meaning of the statute. 90 Fed. Reg. 16102, 16103. The Agencies in turn contend the current definition of “harm” in the ESA regulations that was upheld in Babbitt does not actually reflect the single, best meaning of a “take” under the ESA and therefore should be rescinded.
The Agencies refer to the Babbitt’s Court’s reliance on the now overturned Chevron doctrine and Justice Scalia’s dissent in Babbitt as justifications for the recission. Indeed, the proposed rule echoes two arguments made by Justice Scalia in his dissent. The first argument is that the term "take" as applied to wild animals means to reduce those animals to human control by killing or capturing them. The second is that the noscitur a sociis canon of statutory construction was properly employed by the Court of Appeals during the Babbitt appeal process, even though the Babbitt Supreme Court found otherwise. (Noscitur a sociis is a canon of statutory construction in which the meaning of an unclear or ambiguous word is determined by “gather[ing] meaning from the words around it.” Babbitt at 702.) The Agencies quoted Justice Scalia in the proposed rule and stated the definition of harm should be interpreted like the other verbs in the “take” definition and require an “affirmative act[ ] . . . directed immediately and intentionally against a particular animal—not [an] act[ ] or omission[ ] that indirectly and accidentally cause[s] injury to a population of animals.” Babbit at 719-20.
Next Steps and Implications for Regulated Parties
Although the Agencies state they do not intend to propose a new definition for “harm,” after the Agencies finish reviewing the public comments, they will confirm whether they will proceed with the original proposed rule, issue a new or modified proposed rule, or withdraw the proposed rule. The Agencies emphasize that the proposed recission, if finalized, would not impact permits that have been granted as of the date the recission becomes final.
Any entities with future or currently pending projects that may impact an endangered or threatened species habitat, indirectly or directly, should evaluate the implications the proposed rule may have on any potential habitat-related concerns and regulatory obligations. If the proposed rule is finalized, projects with pending permits as of the date the proposed recission becomes final should consider the possibility of permitting delays or altered regulatory obligations in the event the final rule is appealed. Finally, even though the proposed recission of the definition may limit the scope of species protection provided by the current ESA regulations as to habitat modification, habitats may still be protected at the state or local level. Regulated parties should therefore continue to assess whether any state or local requirements may be applicable to habitat impacts even if the definition of “harm” is rescinded as proposed.
On a related note, on June 9, 2025, FWS published a request for information and comments to improve the overall efficiency and effectiveness of the permitting program under section 10(a) of the ESA. That comment period closed on July 9, 2025.
