Audit, Compliance and Risk Blog

On March 12, the US Environmental Protection Agency (EPA) announced “31 historic actions in the greatest and most consequential day of deregulation in U.S. history.” These actions move to reconsider, and likely reverse, actions from the Biden administration as well as earlier EPA actions dating back to at least 2009. These actions are summarized in a general press release, and accompanied by more than 20 additional releases announcing specific actions; most involve the Clean Air Act (CAA). EPA links these initiatives to President Trump’s latest executive orders (EOs) and policy initiatives (I wrote about the EOs HERE and HERE). In earlier notes I addressed many of the regulatory and policy actions that will now be reconsidered. )

Since returning to office in January, President Trump and his administration have promulgated many actions to reduce and revamp the US federal government, and additional actions focused on specific agencies. I wrote about general approaches to environmental regulation HERE. In addition, The Environmental Protection Agency (EPA) has been a target of specific directives, and new EPA administrator Lee Zeldin has already announced important policy and procedural changes at his agency. The remainder of this note summarizes EPA-specific changes ordered and/or instituted as of the end of February 2025.

The Clean Air Act (CAA) directs the Environmental Protection Agency (EPA) to define “hazardous air pollutants (HAPs)” that may pose acute health hazards, and to impose regulations to reduce those hazards. Controls include permits for “major sources” of HAPs based on “Maximum Achievable Control Technologies (MACT),” and lesser controls for non-major “area sources.” Effective September 10, 2024 EPA has reinstated a policy that an emission source that met major source criteria at the time an applicable MACT became effective is “once in, always in” – even if a source makes binding changes reducing its “potential to emit” below the applicable major source threshold, it still cannot formally requalify as a less-regulated area source. This policy was in force from 1995 until EPA reversed it in January 2018 to allow full reclassification. EPA subsequently codified this approach in a rule issued in 2020. However, EPA has now revised that rule to reinstate “once in, always in.” The rest of this note summarizes CAA requirements for HAP sources, and the latest change. 

On March 1, 2024, the Environmental Protection Agency (EPA) revised Accidental Release Prevention (ARP) program rules under the Clean Air Act (CAA). ARP was authorized by the 1990 Clean Air Act (CAA) Amendments, and is often known by its core requirement that targeted facilities prepare Risk Management Programs (RMPs) to prevent and respond to potential catastrophic releases of chemicals. The adoption finalizes an agency proposal from 2022 (it also recounts a long series of proposal dating back to 2014; I wrote about it HERE), in which the Biden-era EPA proposed to many of the narrowing amendments to RMP/ARP enacted in 2019 during the Trump Administration (I wrote about the 2019 changes HERE).

The rest of this note summarizes the new revisions, noting their differences from current rules.

The Environmental Protection Agency (EPA) announced on February 7. 2024 its decision to tighten one the National Ambient Air Quality Standard (NAAQS) for particulate matter less than or equal to 2.5 microns; (PM-2.5; also call “fines” in contrast to larger particulates). This decision completes EPA’s reconsideration of a decision in 2020 not to adjust the PM-2.5 requirements (I wrote about that decision HERE); the change reflects in part the changed priorities between the Trump and Biden administrations. The rest of this note summarizes NAAQS issues as they apply to PM-2.5.

On January 10, 2024, the U.S. Environmental Protection Agency (EPA), U.S. Department of Justice, and the California Air Resources Board (ARB) filed a settlement agreement with Cummins, Inc. covering nearly one million Ram vehicles for which Cummins supplied diesel engines with illegal software-based “defeat devices” that produced misleading emission certification results compared with significantly higher emissions while the vehicles are in actual use. Cummins will pay the largest CAA penalties ever ($1,675 million in federal and state penalties), will fund environmental mitigation projects to compensate for excess nitrogen oxides (NOx) emissions ($175 million), and will also recall 630,000 vehicles (model years 2013-2019) to remove the defeat devices (estimated costs $150 million, including warranty extensions). Cummins will also implement corporate governance, organizational, and technical process reforms to minimize the likelihood of future violations.

Since 1990, the Clean Air Act (CAA) has defined a list of Hazardous Air Pollutants (HAPs), requiring the U.S. Environmental Protection Agency (EPA) to set emissions standards for many sources of these pollutants. HAPs include heavy metals, organics, and other airborne pollutants that are not otherwise regulated as “criteria” air pollutants (such as carbon monoxide, particulate matter, and ground level ozone). The 1990 CAA Amendments included a list of 189 HAPs (later corrected to 188), and empowered EPA to modify the list. In the intervening decades, EPA conducted rulemakings and deleted four initially-listed HAPs, but until 2022 had never added a new HAP. However, EPA has now added 1-bromopropane (1-BP) as a new HAP, effective February 4, 2022.