Oklahoma Bar Journal

Tribal Regulation of the Environment and Natural Resources Under Federal Environmental Laws

By Conor P. Cleary

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Governmental regulation of the environment and natural resources traditionally has been described as one of “cooperative federalism.”[1] The federal government is the default administrator of federal environmental statutes like the Clean Air Act or Clean Water Act. But these statutes, and others like them, authorize states to step into the shoes of the federal regulatory agencies and assume responsibility for administering environmental laws. The federal government maintains a supervisory role to ensure the state meets the minimum standards of the federal environmental laws, but otherwise, the state is the primary regulatory sovereign. In this way, the federal and state governments work cooperatively to achieve the goals of federal environmental statutes.

This model of federal-state cooperation, however, can obscure the role of a third sovereign with the power to regulate the environment and natural resources – tribal governments. As this article will explain, most federal environmental laws now contain provisions treating Indian tribes as states and authorizing tribes to be the primary regulators of the environment and natural resources within a tribe’s Indian Country. And even where an environmental law does not treat a tribe as a state or is ambiguous about its application, tribes still have inherent authority to regulate some uses of natural resources in areas within their jurisdiction.[2]


Congress enacted most of the major environmental laws in the late 1960s and 1970s. Prior to that time, environmental law was a “highly decentralized system built on private law principles.”[3] “[T]he common law was the legal system’s primary vehicle for responding to environmental disputes[,] ... [relying] largely on doctrines of nuisance law to resolve these conflicts[.]”[4]

By the early 1960s, however, an emerging “[a]wareness that pollutants do not respect state, or even national boundaries, grew rapidly.”[5] Rachel Carson’s Silent Spring “began to shift public discourse about the environment ... and was a significant driver in the 1970 formation of the U.S. Environmental Protection Agency.”[6] In the 1970s – known as the “environmental decade” – Congress passed several comprehensive federal environmental laws that “established the ground rules for national environmental protection efforts.”[7] For example, the National Environmental Policy Act (NEPA) required federal agencies to evaluate the environmental effects of their actions.[8] The Endangered Species Act prohibited actions that jeopardized threatened and endangered species.[9] The Clean Air Act and Clean Water Act placed limits on air, water and other pollutants.[10] And the Resource Conservation and Recovery Act regulated the disposal of hazardous wastes.[11]

These statutes all have a similar framework. They establish minimum standards for the protection of the environment. The federal government – typically the Environmental Protection Agency (EPA) – is the default regulator that administers the federal statute and its implementing regulations. The statutes contain an option for states to apply for and receive approval to develop and implement their own environmental regulatory programs. State programs must meet the minimum standards set forth in the federal statute but can impose more stringent regulations if desired. A state that assumes the role of primary regulator “is said to have achieved ‘primacy.’”[12]

The first iterations of these statutes did not address their application in Indian Country, nor did they contain an option for tribes to assume the role of primary regulator as they did for states. This omission prompted litigants to initially challenge the authority of the EPA to enforce environmental statutes in Indian Country. For example, the Safe Drinking Water Act (SDWA), which “establishes a regulatory mechanism to insure the quality of publicly supplied drinking water [and] ... a regulatory program designed to prevent the endangerment of underground drinking water sources[,] ... did not expressly address the questions of Indian lands or Indian sovereignty” when it was first enacted.[13] In Phillips Petroleum Company v. United States Environmental Protection Agency, Phillips Petroleum argued that this omission “preclude[d] any interpretation of the statute which would allow it to apply to Indian lands[.]”[14] At issue was the EPA’s promulgation of an underground injection control (UIC) program regarding the Osage Nation mineral estate.[15]

The 10th Circuit Court of Appeals rejected this argument. It reasoned that the SDWA applied to “persons,” which the statute defined to include Indian tribes, and that there is a “presumption that Congress intends a general statute applying to all persons to include Indians and their property interests.”[16] It also concluded that the purpose of the SDWA was to enact minimum national standards for the protection of drinking water, and the exclusion of Indian lands from the reach of the statute would undermine this congressional policy.[17] It also afforded deference to the EPA’s interpretation of the statute as applying to Indian lands.[18]

States also argued that to the extent the federal environmental statutes applied in Indian Country, states should be the primary regulator there. The EPA, however, interpreted the statutes to not authorize state regulation in Indian Country. Several federal appellate court rulings upheld the EPA’s interpretation. For example, in State of Washington Dep’t of Ecology v. EPA, the EPA had “refused to permit the State of Washington to apply its state hazardous waste regulations ... on ‘Indian lands’” under the Resource Conservation and Recovery Act (RCRA).[19] Although the state and legislative history were “totally silent on the issue of state regulatory jurisdiction on the reservations,”[20] the court concluded that the EPA had reasonably interpreted the RCRA not to authorize state jurisdiction based on “well-settled principles of federal Indian law” that “States are generally precluded from exercising jurisdiction over Indians in Indian Country unless Congress has clearly expressed an intention to permit it.”[21]


During the 1980s, Congress amended most of the federal environmental statutes to make clear that they applied in Indian Country.[22] The amendments also included what are known as “treatment as a state” provisions (TAS) that authorized Indian tribes to be treated as states and gain primacy to administer tribal environmental programs.[23] The statutes define the geographic area in which tribes may administer the environmental programs – typically within the tribe’s reservation or other areas within the tribe’s jurisdiction.[24]

When the environmental laws were first amended to treat tribes as states, there were questions about the scope and extent of that authority. At a minimum, tribes could administer the environmental laws to the extent of their inherent authority as a sovereign government. Tribes can even administer provisions of federal environmental laws when the law does not expressly authorize tribal regulation. For example, in City of Albuquerque v. Browner, the 10th Circuit held that a tribe had the inherent authority to issue water quality standards more stringent than those provided in the Clean Water Act despite the fact that the TAS provision of the CWA did not expressly include the section of the CWA dealing with promulgation of water quality standards.[25] The court found that this did not “prevent Indian tribes from exercising their inherent sovereign power to impose standards or limits that are more stringent than those imposed by the federal government.”[26]

On reservations where there are significant amounts of land owned by non-Indians, however, a tribe’s inherent authority is greatly limited. Due to rulings by the U.S. Supreme Court, tribes have been largely divested of their inherent authority to regulate land owned by non-Indians and can only regulate non-Indian land if they meet one of two relatively narrow exceptions. Because within many Indian reservations today there is a checkerboard pattern of Indian and non-Indian ownership of individual tracts of land, a tribe’s ability to implement a uniform environmental policy within the reservation is frustrated by these limits on its inherent authority. In this circumstance, Congress can delegate to tribes powers above and beyond those that tribes possess inherently, including the authority to regulate all land within a reservation – even land owned by non-Indians.[27]


In the late 1800s and early 1900s, Congress enforced a policy of allotment whereby it “sought to pressure many tribes to abandon their communal lifestyles and parcel their lands into smaller lots owned by individual tribe members.”[28] As a result of this policy, “individual Tribe members were eventually free to sell their land,”[29] and many “individual parcels have passed hands to non-Indians.”[30] These non-Indian-owned lands are often referred to as “non-Indian fee lands” or just “fee lands.” It is not uncommon, then, for there to be many tracts of non-Indian fee land within the exterior boundaries of an Indian reservation. In many cases, the vast majority of land within a reservation is owned in fee by non-Indians. The reservations of the Five Tribes affirmed by McGirt and its progeny are good examples of this phenomenon.

After Congress amended the various federal environmental statutes to allow tribal primacy,[31] the EPA promulgated regulations interpreting the statutes and defining the extent of the tribes’ geographic jurisdiction. One of the most vexing questions the EPA encountered was whether a statute’s authorization of tribal regulation within a “reservation” included all land within the reservation, including non-Indian fee land.

Initially, the EPA took a cautious approach and generally required tribes to demonstrate inherent authority to regulate non-Indian fee lands before allowing tribes to administer federal environmental programs on all lands within a reservation. This required the tribe to satisfy what is known as the Montana test. In 1981, the U.S. Supreme Court held that an Indian tribe presumptively lacks the inherent power to regulate conduct on non-Indian fee lands located within a reservation unless it satisfies one of two exceptions.[32] First, tribes can regulate the conduct of non-Indians “who enter consensual relationships with the tribe or its members, through commercial dealing, contracts, leases, or other arrangements.”[33] This is known as the “consensual relations” exception. Second, a tribe may regulate the conduct of non-Indians on fee lands “when that conduct threatens or has some direct effect on the political integrity, the economic security, or the health or welfare of the tribe.”[34] This is often referred to as the “direct effects” exception.

Although the EPA required tribes to satisfy a Montana exception before granting them authority to regulate non-Indian fee lands, the EPA generally concluded that the regulation of things like air and water pollutants satisfied the second Montana exception since pollution threatened the health and welfare of the tribe.[35] However, requiring tribes to demonstrate jurisdiction by satisfying the Montana test on a case-by-case basis was a time-consuming and resource-intensive process that delayed approval of tribal regulation.[36]

Later, the EPA concluded that statutes like the Clean Air Act and Clean Water Act expressly delegated authority to the tribes to regulate all land within their reservations, including non-Indian fee land, obviating the need for the tribe to satisfy a Montana exception on a case-by-case basis. These interpretations were upheld by the federal courts. For example, in Arizona Public Service Company v. EPA, the U.S. Court of Appeals for the District of Columbia Circuit concluded that the Clean Air Act constitutes an express delegation of regulatory authority over non-Indian fee lands within a reservation.[37] The Clean Air Act authorizes tribal regulation “within the exterior boundaries of a reservation or other areas within the tribe’s jurisdiction.”[38] The EPA interpreted “[t]he statute’s clear distinction between areas ‘within the exterior boundaries of the reservation’ and ‘other areas within the tribe’s jurisdiction’ [as] carry[ing] with it the implication that Congress considered the areas within the exterior boundaries of a tribe’s reservation to be per se within the tribe’s jurisdiction.”[39] The court, therefore, found that the Clean Air Act authorizes tribal regulation of all land within a reservation, including non-Indian fee land.[40]


Discussions of environmental regulatory jurisdiction too often ignore the inherent sovereignty of Indian tribes and the role of tribes in administering federal environmental laws. When analyzing the allocation of jurisdiction to regulate the environment and natural resources in Indian Country, elected officials, agency personnel and attorneys would be wise to foreground rather than footnote questions of tribal authority.


Author’s Note: The views expressed in this article are those of Mr. Cleary and do not necessarily represent the views of the Department of the Interior or the United States government.


Conor P. Cleary is the Tulsa field solicitor for the U.S. Department of the Interior. He holds an LL.M. in American Indian and Indigenous law from the TU College of Law and a J.D. from the OU College of Law.





[1] See, e.g., Hodel v. Va. Surface Min. & Reclamation Ass’n, 452 U.S. 264, 289 (1981) (discussing the Surface Mining Control and Reclamation Act).

[2] This article focuses on tribal authority to regulate the environment and natural resources within their territories pursuant to a variety of federal environmental statutes. This is not to suggest, however, that this is the extent of tribal environmental authority. Since time immemorial, Indigenous peoples have been interested in the health and sustainability of their lands and natural environments. See Frank Pommersheim, “The Reservation as Place: A South Dakota Essay,” 34 S.D. L. Rev. 246, 246-47 (1989). Their traditional ecological knowledge (TEK) – representing “the generation, accumulation, and transmission of knowledge and the adaptive management of local ecological resources” – contribute[s] to the conservation of biodiversity, rare species, protected areas, ecological processes, and to sustainable resource use in general.” Fikret Berkes et. al, “Rediscovery of Traditional Ecological Knowledge as Adaptive Management,” 10 Ecological Applications 1251, 1251 (2000). Only recently have federal agencies recognized the value of TEK and begun to incorporate it into their programs and decision-making. See, e.g., Office of Science and Technology Policy and CEQ, Guidance for Federal Departments and Agencies on Indigenous Knowledge, Nov. 30, 2022, available at https://bit.ly/3J8I7v6 (last accessed Dec. 3, 2023).

[3] Robert V. Percival, “Regulatory Evolution and the Future of Environmental Policy,” 1997 U. Chi. Legal F. 159, 159 (1997).

[4] Id. at 161.

[5] Id. at 163-64.

[6] Rob Dunn, “In Retrospect: Silent Spring,” 485 Nature 578, 578 (2012).

[7] Percival, supra note 3, at 164.

[8] Pub. L. No. 91-190, 83 Stat. 852, codified at 42 U.S.C. §4321 et seq.

[9] Pub. L. No. 93-205, 87 Stat. 884, codified at 16 U.S.C. §1531 et seq.

[10] Clean Air Act Amendments of 1970, Pub. L. No. 91-604, 84 Stat. 1676, codified at 42 U.S.C. §7401 et seq.; Clean Water Act, Pub. L. No. 92-500, 86 Stat. 816, codified at 33 U.S.C. §1251 et seq.

[11] Pub. L. No. 94-580, 90 Stat. 2795, codified at 42 U.S.C. §6901 et seq.

[12] Farrell-Cooper Min. Co. v. U.S. Dep’t of the Interior, 728 F.3d 1229, 1232 (10th Cir. 2013).

[13] Phillips Petroleum Co. v. U.S. E.P.A., 803 F.2d 545, 547 and 553 (10th Cir. 1986).

[14] Id. at 553.

[15] Id. at 549. The entire mineral estate underlying Osage County is held in trust by the United States for the benefit of the Osage Nation. See Act of June 28, 1906, §3, 34 Stat. 539, 543.

[16] Id. at 556 (citing Federal Power Comm’n v. Tuscarora Indian Nation, 362 U.S. 99, 116-18 (1960)).

[17] Id. at 554-56.

[18] Id. at 557.

[19] Washington, Dep’t of Ecology v. U.S. EPA, 752 F.2d 1465, 1466 (9th Cir. 1985).

[20] Id. at 1469.

[21] Id. at 1469-70 (footnote and citations omitted).

[22] See, e.g., Safe Drinking Water Amendments of 1986, Pub. L. No. 99-339, §302, 100 Stat. 642, 666 (1986).

[23] See id. at §302, 100 Stat. at 665-66.

[24] For example, the Clean Air Act authorizes treatment of Indian tribes as states “within the exterior boundaries of the reservation or other areas within the tribe’s jurisdiction.” 42 U.S.C. §7601(d). The Clean Water Act authorizes TAS with respect to water resources “which are held by an Indian tribe, held by the United States in trust for Indians, held by a member of an Indian tribe if such property interest is subject to a trust restriction on alienation, or otherwise within the borders of an Indian reservation.” 33 U.S.C. §1377(e).

[25] 97 F.3d 415 (10th Cir. 1996).

[26] Id. at 423.

[27] See U.S. v. Mazurie, 419 U.S. 544, 554 (1975); see also Montana v. U.S., 450 U.S. 544, 564 (1981) (inherent sovereignty over nonmembers “cannot survive without express congressional delegation”).

[28] McGirt v. Oklahoma, 591 U.S. __, 140 S. Ct. 2452, 2463 (2020) (citation omitted).

[29] Id at 2463.

[30] Id. at 2464.

[31] In Oklahoma, the ability of tribes to obtain primacy to administer environmental laws overseen by the Environmental Protection Agency (such as the Clean Air Act or Clean Water Act) has been limited by statute. In 2005, Congress attached a rider to the Safe, Accountable, Flexible, Efficient Transportation Equity Act (SAFETEA) that allows the state to achieve primacy over Indian Country lands and requires state consent to the treatment of a tribe as a state. See Pub. L. No. 109-59, §10211, 119 Stat. 1144 (2005). The state of Oklahoma generally may not administer environmental laws under the jurisdiction of an agency other than the EPA in Indian Country within the state. See Oklahoma v. U.S. Dep’t of the Interior, 640 F. Supp. 3d 1130 (W.D. Okla. 2022) (Surface Mining Control and Reclamation Act).

[32] See Montana v. U.S., 450 U.S. 544 (1981).

[33] Id. at 565 (citations omitted).

[34] Id. at 566 (citations omitted).

[35] See Montana v. EPA, 137 F.3d 1135 (9th Cir. 1998). The EPA initially interpreted the Clean Water Act as allowing tribal regulation of water resources on nonmember fee land only where the tribe could demonstrate inherent authority under one of the Montana exceptions, id. at 1138-39, but found that tribal regulation was justified under the direct effects exception. Id. at 1141. The 9th Circuit upheld the EPA’s decision. Id.

[36] See 81 Fed. Reg. 30183, 30189 (May 16, 2016) (noting that requiring tribes to satisfy the Montana test “constituted the single greatest administrative burden” in the approval process).

[37] Arizona Pub. Serv. Co. v. U.S. EPA, 211 F.3d 1280, 1288 (D.C. Cir. 2000).

[38] 42 U.S.C. §7601(d)(2)(B).

[39] Arizona Pub. Serv. Co., 211 F.3d at 1288.

[40] Id. The EPA later revisited its interpretation of the Clean Water Act and concluded it contained an express delegation of authority to tribes to regulate nonmember fee land within their reservations. 81 Fed. Reg. 30183 (May 16, 2016).

Originally published in the Oklahoma Bar JournalOBJ 95 No. 5 (May 2024)

Statements or opinions expressed in the Oklahoma Bar Journal are those of the authors and do not necessarily reflect those of the Oklahoma Bar Association, its officers, Board of Governors, Board of Editors or staff.