US Environmental Protection Agency (EPA) Administrator Lee Zeldin announced the agency will be kicking off a formal reconsideration of the 2009 Endangerment Finding in collaboration with the Office of Management and Budget (OMB) and other relevant agencies. EPA also intends to reconsider all of its prior regulations and actions that rely on the Endangerment Finding.

The 2009 Endangerment Finding (earlier post) is a formal determination made under the Clean Air Act that concluded that greenhouse gases (GHGs) pose a threat to public health and welfare, thereby classifying them as pollutants that can be regulated. This finding specifically identified six GHGs —carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF₆)—as contributing to climate change through their accumulation in the atmosphere.

The EPA’s then Administrator (Lisa Jackson) signed off on two key conclusions: first, that elevated GHG concentrations endangered public health and welfare, and second, that emissions from new motor vehicles and engines contributed to this pollution.

This ruling didn’t impose regulations directly but laid the legal groundwork for the EPA to develop subsequent rules.

In President Trump’s Day One Executive Order, “Unleashing American Energy,” he gave the EPA Administrator a 30-day deadline to submit recommendations on the legality and continuing applicability of the 2009 Endangerment Finding. After submitting these recommendations, EPA can now announce its intent to reconsider the 2009 Endangerment Finding.

When EPA made the Endangerment Finding in 2009, EPA now says that the agency did not consider any aspect of the regulations that would flow from it. EPA’s view then was that the Finding itself did not impose any costs, and that EPA could not consider future costs when making the Finding. EPA has subsequently relied on the Endangerment Finding as part of its justification for seven vehicle regulations with an aggregate cost of more than one trillion dollars, according to figures in EPA’s own regulatory impact analyses. The Endangerment Finding has also played a significant role in EPA’s justification of regulations of other sources beyond cars and trucks.

Administrator Zeldin also announced the agency will reconsider the Model Year 2027 and Later Light-Duty and Medium-Duty Vehicles regulation and Greenhouse Gas Emissions Standards for Heavy-Duty Vehicles. In addition to imposing more than $700 billion in regulatory and compliance costs, these rules provided the foundation for the Biden-Harris electric vehicle mandate, according to the EPA.

Additionally, EPA is reevaluating other parts of the earlier EPA Clean Trucks Plan. This includes the 2022 Heavy-Duty Nitrous Oxide (NO_x) rule.

This reconsideration was announced in conjunction with a number of other actions that, combined, represent the greatest day of deregulation in the history of the United States, the EPA claimed. These actions include:

• Reconsideration of regulations on power plants (Clean Power Plan 2.0)

• Reconsideration of regulations throttling the oil and gas industry (OOOO b/c)

• Reconsideration of Mercury and Air Toxics Standards that improperly targeted coal-fired power plants (MATS)

• Reconsideration of mandatory Greenhouse Gas Reporting Program that imposed significant costs on the American energy supply (GHG Reporting Program)

• Reconsideration of limitations, guidelines and standards (ELG) for the Steam Electric Power Generating Industry to ensure low-cost electricity while protecting water resources (Steam Electric ELG)

• Reconsideration of wastewater regulations for coal power plants to help unleash American energy (Oil and Gas ELG)

• Reconsideration of Biden-Harris Administration Risk Management Program rule for oil and natural gas refineries and chemical facilities

• Reconsideration of technology transition rule that forces companies to use certain technologies that increased costs on food at grocery stores and semiconductor manufacturing (Technology Transition Rule)

• Reconsideration of Particulate Matter National Ambient Air Quality Standards that shut down opportunities for American manufacturing and small businesses (PM 2.5 NAAQS)

• Reconsideration of multiple National Emission Standards for Hazardous Air Pollutants for American energy and manufacturing sectors (NESHAPs)

• Restructuring the Regional Haze Program

• Overhauling Biden-Harris Administration’s “Social Cost of Carbon”

• Redirecting enforcement resources to EPA’s core mission to relieve the economy of unnecessary bureaucratic burdens that drive up costs for American consumers (Enforcement Discretion)

• Terminating the Environmental Justice and DEI arms of the agency (EJ/DEI)

• Ending the “Good Neighbor Plan” which the Biden-Harris Administration used to expand federal rules to more states and sectors beyond the program’s traditional focus and led to the rejection of nearly all State Implementation Plans

• Working with states and tribes to resolve massive backlog with State Implementation Plans and Tribal Implementation Plans

• Reconsideration of exceptional events rulemaking to work with states to prioritize the allowance of prescribed fires within State and Tribal Implementation Plans (Exceptional Events)

• Reconstituting Science Advisory Board and Clean Air Scientific Advisory Committee (SAB/CASAC)

• Prioritizing coal ash program to expedite state permit reviews and update coal ash regulations (CCR Rule)

• Utilizing enforcement discretion to further North Carolina’s recovery from Hurricane Helene