Air and Climate
New Source Performance Standards for Electric Generating Units
On May 9, 2024, the United States Environmental Protection Agency (EPA) published a final rule establishing new source performance standards for new, modified, and reconstructed fossil fuel-fired electric generating units (EGUs) and repeal of the Affordable Clean Energy Rule. Coal-fired EGUs with an anticipated useful life beyond January 1, 2039, are expected to meet by January 1, 2032, an emission rate based on achieving 90% carbon capture through use of carbon capture and sequestration; coal-fired EGUs that commit to cease operations by January 1, 2039, are expected to meet an emission rate by January 1, 2030, based on co-firing 40% natural gas; and those that plan to permanently cease operations prior to January 1, 2031, have no emission reduction obligations under the rule. Twenty-five states challenged EPA’s final rule in the D.C. Circuit. West Virginia v. EPA, Case No. 24-1120 (D.C. Cir. filed May 9, 2024). Oral argument occurred on December 6, 2024. If the May 9, 2024, rule is upheld, the Trump administration might seek to alter it with a new rulemaking.
As noted in the final rule, EPA sought additional time to deliberate and determine the best way to address emissions from existing gas turbines. No proposed rule dealing with existing gas turbines was issued prior to the end of the Biden administration. It appears unlikely that the new administration will move forward with the stringent standards that the Biden administration had proposed for existing natural gas-fired EGUs.
National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters
During the Biden administration, EPA promulgated national emission standards for hazardous air pollutants from coal-fired, biomass-fired, and liquid-fired industrial boilers; commercial and institutional boilers; and process heaters. The standards apply to emissions of mercury, hydrogen chloride, particulate matter, and carbon monoxide. There are separate standards for “existing” and “new” sources; new sources are subject to more restrictive standards. The D.C. Circuit reversed EPA’s application of the standard for “new” sources. US Sugar Corporation v. EPA, Case No. 22-1271 (D.C. Cir. 2024). The Trump administration could revisit the standards altogether.
National Ambient Air Quality Standard for Fine Particulate Matter
On March 6, 2024, EPA published a stricter annual national ambient air quality standard for fine particulate matter (PM2.5), set to be effective May 6, 2024. The new standard lowered the allowable annual PM2.5 level from 12 to 9 micrograms per cubic meter and required states to designate areas as meeting or not meeting the new standard by February 7, 2025, with compliance deadlines starting in 2032. The lowering of the standard would result in more of the US being classified as non-attainment and would cause some industrial facilities not to be permitted. Though the deadlines for implementing emission controls at the source level do not begin until 2032, other regulatory developments, including the state plans to implement the standard, would begin starting this year. Two dozen states filed suit against EPA to vacate the agency’s final action on March 6, 2024 in the D.C. Circuit. Kentucky v. EPA, Case No. 24-1050 (D.C. Cir. filed Mar. 6, 2024). Oral argument took place on December 16, 2024. The Trump administration has not announced how it might try to alter this regulation.
Startup, Shutdown, and Malfunction
An EPA rule with major impact on industry concerns whether states can allow exemptions or affirmative defenses to excess emissions from unit startups, shutdowns, or malfunctions (SSM), when pollution controls often cannot fully function. These exemptions have long been included in Title V permits until EPA issued a rule prohibiting those exemptions, which meant that thousands of facilities would not be able to comply with their permits. In March of last year, the D.C. Circuit largely vacated the rule prohibiting these SSM provisions. Environmental Comm. of Fla. Elec. Power Coordinating Grp., Inc. v. EPA, 94 F.4th 77 (D.C. Cir. 2024). The Biden administration proposed a rule to implement a standard for SSM, accounting for the D.C. Circuit’s ruling. That rule was withdrawn on November 26, 2024. We should expect there to be a different implementing rule from the Trump administration.
Methane from Oil and Gas Operations
On March 8, 2024, EPA published a final rule to reduce methane from oil and natural gas operations, effective May 7, 2024. The rule sets forth new source performance standards to limit emissions of methane and other volatile organic compounds, from new, modified, and reconstructed sources. Recognizing the Trump administration’s emphasis on domestic fossil fuel-based energy production, this rule is a likely target.
Water
Waters of the United States Rule
The term “waters of the United States” (WOTUS) refers to those waters that are within the jurisdiction of the US federal government to regulate under the Clean Water Act. The definition has been the subject of conflicting regulations by successive administrations and litigated extensively. In 2023, the Supreme Court of the United States ruled in Sackett v. EPA that federal jurisdiction extends only to waterways and adjacent wetlands that have a “continuous surface connection” to traditionally navigable waters of the United States, a narrower reading than the Supreme Court had applied previously. 598 US 651, 678 (2023). The Biden administration issued a regulation to implement Sackett. Twenty-six states challenged the Biden rule on grounds that it would extend federal jurisdiction more broadly than Sackett. While that litigation is ongoing, the Biden-era rule applies in 24 states, the District of Columbia, and US territories. In the remaining 26 states (the states currently challenging the Biden-era rule), the agencies are interpreting WOTUS consistent with the pre-2015 regulatory regime and the Supreme Court’s decision in Sackett. Depending on the outcome of the pending litigation, we could see further rulemaking on this issue.
401 Water Quality Certification
Section 401 of the Clean Water Act (CWA) requires applicants for federal permits or licenses for activities that may result in a discharge to a jurisdictional water body to obtain certification from the affected state that the proposed activity will comply with state water quality standards. The Trump and Biden administrations each promulgated rules regarding Section 401 certifications. The scope of Section 401 certifications and the process can significantly affect the time it takes to get a federal permit and the environmental conditions imposed on the permit. The Biden-era rule was finalized and went into effect in November 2023. Eleven states and several industry groups sought to block the rule, claiming that it “imposes mandatory requirements on states that exceed their statutory obligations under the CWA and disrupts the CWA’s cooperative federalism framework.” Louisiana v. EPA, Case No. 2:23-cv-01714 (W.D. La). The litigation remains pending. The Mandates for Leadership publication of Project 2025 specifically mentions the Section 401 certification rule as needing action by the new administration.1
Chemicals
Per- and Polyfluoroalkyl Substances
Over the past 18 months, EPA rapidly accelerated regulation of per- and polyfluoroalkyl substances (PFAS) under several statutes:
- On April 19, 2024, EPA issued a final rule designating two PFAS – perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), including their salts and structural isomers – as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The designation of PFOA and PFOS as hazardous substances allows EPA and private parties to recover response costs for investigations and cleanup. Although this is a final rule, it remains to be seen how this Trump administration may proceed with enforcement.
- On April 10, 2024, EPA issued a final rule that established national drinking water standards for six PFAS. One might expect that there will be no more PFAS compounds added to this list during the Trump administration.
- On October 11, 2023, EPA issued a final rule requiring anyone who manufactures (including importing) or has manufactured (including imported) PFAS or PFAS-containing articles in any year since January 1, 2011, to electronically report information regarding PFAS uses, production volumes, disposal, exposures, and hazards. The beginning of the reporting period is July 2025 due to budgetary constraints.
- On February 8, 2024, EPA issued a proposed rule under the Resource Conservation and Recovery Act (RCRA) regulations that adds nine PFAS compounds to its list of hazardous constituents. Comments were due on this proposed rule in April 2024. From the indications of the Trump administration, these additional PFAS compounds are unlikely to be added to the hazardous constituents list, or, at minimum, such additions are likely to be severely delayed.
Toxic Substances Control Act Regulations
The Biden administration issued rules under the Toxic Substances Control Act (TSCA) regulating a number of chemicals, including trichloroethylene (TCE) and tetrachloroethylene (PCE). TCE and PCE are common industrial solvents, and PCE is widely used in dry cleaning. EPA’s rules sought to ban the use of TCE over time, with most risks eliminated within a year, and to prohibit the manufacturing, processing, and distribution for all consumer and many commercial uses of PCE. On January 28, 2025, EPA delayed the effective date for TCE until March 21, 2025, in response to President Trump’s “Regulatory Freeze Pending Review” executive order. This rule was previously stayed and never went into effect. There is a pending challenge of the PCE rule in the Fifth Circuit.
RCRA/Regulated Waste
How coal ash is to be managed has been debated for years. On May 8, 2024, t EPA published a final rule addressing coal ash disposal. EPA established requirements for groundwater monitoring, corrective action, and closure and post-closure care for coal combustion residual surface impoundments and landfills. On January 31, 2025, electric utility entities and states filed lawsuits against EPA’s May 2024 rule, arguing it exceeds EPA’s authority under the Resource Conservation and Recovery Act. City Utilities of Springfield, MO v. EPA, Case No. 24-1200 (D.C. Cir. filed on January 31, 2025). The new administration appears likely to adopt a different position regarding the 2024 rule than that of the Biden administration.
Threatened and Endangered Species
Three executive orders so far include language that seeks to eliminate or reduce requirements under the Endangered Species Act (ESA) for certain projects, namely oil and gas projects (under the “Declaring a National Energy Emergency” executive order) and water distribution projects in California (under the executive orders titled “Putting People Over Fish: Stopping Radical Environmentalism to Provide Water to Southern California” and “Emergency Measures to Provide Water Resources in California and Improve Disaster Responses in Certain Areas”).
The “blanket protections” rule for threatened species has undergone a back-and-forth between the Trump and Biden administrations. The blanket protections rule extends many of the protections for endangered species to newly listed threatened species, without the need for species-specific protection. The Trump administration removed the blanket protections rule, and the Biden administration reinstated it. The second Trump administration might seek to reverse the government’s position on this issue once again.
At the time of the presidential transition, several key proposed species listings were not yet finalized. Among these are the proposed listings for the tricolored bat and the monarch butterfly, both of which reside across a large swath of the United States. Listing of these species could have an impact on a wide range of development projects and other activities. The Trump administration has not yet stated whether it will proceed with these listings.
National Environmental Policy Act
Another target of the early days of the second Trump administration has been the National Environmental Policy Act (NEPA) and, more specifically, the Council on Environmental Quality
(CEQ). By statute, NEPA created CEQ, which falls within the Executive Office of the President. CEQ’s scope includes reviewing and appraising agencies’ compliance with NEPA, making recommendations to the president with respect to NEPA, and developing and recommending national policies to foster and promote the improvement of environmental quality. CEQ issued its first comprehensive NEPA regulations in 1978. Over the years, CEQ has amended its regulations, with its role and scope often being influenced by various executive orders and policy shifts.
As part of the “Unleashing American Energy” executive order, President Trump revoked a Carter administration order that gave CEQ authority to issue binding regulations implementing NEPA. Trump’s order also directed CEQ to, within 30 days, “propose rescinding” all prior CEQ regulations and to issue guidance to agencies on NEPA implementation.
This order was preceded by a case that had already invalidated CEQ’s authority to issue binding regulations. Last year, a D.C. Circuit panel ruled that CEQ lacked legal authority to issue binding regulations. See Marin Audubon Soc’y v. Fed. Aviation Admin., 121 F.4th 902 (D.C. Cir. 2024). This was significant because the D.C. Circuit found that CEQ’s regulations were broader than the Federal Aviation Administration’s own NEPA implementing regulations. On January 31, 2025, the D.C. Circuit denied a petition for rehearing en banc. In the absence of CEQ regulations, agencies may proceed under their own NEPA-implementing regulations, which could be inconsistent with one another or narrower than CEQ regulations.
Environmental Justice
The Trump administration’s early actions in its second term show strong opposition to environmental justice, reversing many Biden-era policies. These orders have revoked several measures aimed at addressing environmental injustices, including the rescission of a Clinton executive order that was foundational for federal efforts to combat environmental discrimination on minority and low-income populations. The administration’s shift may lead to the exclusion of environmental justice considerations from NEPA reviews. Additionally, the orders have eliminated various environmental justice programs across federal agencies. On February 5, 2025, EPA said 168 staffers who have been focused on environmental justice were placed on indefinite administrative leave. States with their own environmental justice laws may continue enforcement independently of federal policy.
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1 Project 2025 is a policy road map drafted by the Heritage Foundation that aims to reshape the federal government to implement conservative policies in environmental and other sectors. Project 2025 is not an official policy statement of the Trump administration.
