In March 2025, Administrator Zeldin announced that EPA will reconsider a number of regulations in order to advance various executive orders issued by President Trump and fulfill EPA’s own Powering the Great American Comeback Initiative. These efforts include the 2024 ambient air standard for particulate matter, the 2009 endangerment finding, and the scope of jurisdiction over ‘adjacent wetlands after the Supreme Court’s 2023 decision in Sackett.
In the Biden Administration, EPA lowered the National Ambient Air Quality Standard for particulate matter, the PM 2.5 NAAQS. The standard was reduced to levels that were close to background levels in some areas. EPA announced it is “revisiting” the lower standard because, among other things, the lower standard “raised serious concerns from states across the country and served as a major obstacle to permitting.”
So far, though, EPA has not issued a proposal to revisit the PM 2.5 NAAQS. It faces some hurdles in doing so. It must be done through the administrative rule-making process, which includes public notice and comment. Further, to survive judicial review, EPA must provide a reasoned explanation for the basis of the revision. EPA also stated it would “soon release guidance to increase flexibility on NAAQS implementation…and direction on permitting obligations.” However, these items have not yet been issued.
In announcing the roll-back in March, Administrator Zeldin stated that EPA is “driving a dagger straight into the heart of the climate change.” Over the summer, EPA issued its proposal to reconsider the 2009 Endangerment Finding, in which EPA concluded that carbon dioxide, methane, and other greenhouse gases threaten public health and welfare and which EPA utilized to impose greenhouse gas emissions standards for vehicles as well as a host of other regulations.
In the reconsideration proposal, EPA mentioned the overall regulatory impact of the Finding. EPA stated that the Finding was relied on as justification for certain regulations with an aggregate cost of more than one trillion dollars. Additionally, EPA mentioned significant uncertainties in the science and assumptions used to justify the Finding and major Supreme Court decisions that provided new guidance on how EPA should interpret statutes.
The fate of the reconsideration is uncertain. A public hearing was held, and the public comment period ran into September. Opponents of the reconsideration have commented that the reasoning EPA provided for the reconsideration is flawed. For example, the National Academies of Sciences, Engineering, and Medicine published a report focusing on climate science since 2009 and stating that the “evidence for current and future harm to human health and welfare created by human-caused greenhouse gases is beyond scientific dispute.” In short, a final decision to reverse the Finding will be met with legal challenges which could last for years.
The Supreme Court’s decision in Sackett provided a clear statement about the limits of jurisdiction over adjacent wetlands pursuant to the Clean Water Act. Until the Trump Administration, the EPA and the Corps of Engineers seemed reluctant to embrace this clear statement. However, the Trump Administration issued guidance in March 2025 expressly curtailing the scope of jurisdiction. Adjacent means ‘physically abutting’ and there must be a continuous surface connection, that is, directly abutting a requisite jurisdictional water, to be jurisdictional as an adjacent wetland. Wetlands with only an intermittent physically remote hydrologic connection do not have the necessary connection and are not jurisdictional. EPA has promised a rulemaking to codify these interpretations. EPA seems to be moving forward with its de-regulatory agenda, with some actions farther along than others. Still, once issued, any de-regulation will be met with litigation so the outcome of Administrator Zeldin’s overall agenda is anything but certain.
BSW Environmental Blog 