Contributed by Jared S. Saterfiel, Principal/District Manager, PPM Consultants
For years, diesel truck owners have boasted about “deleting” their rigs—ripping out the systems that force-feed Diesel Exhaust Fluid (DEF) into engines in the name of cleaner air. Now, in a twist of irony, Washington may be doing its own delete job. With the EPA’s July 2025 proposal to erase greenhouse gas regulations—and by extension, the very rules that created the DEF mandate—drivers who once paid to sidestep emissions equipment may soon find the government hitting the delete button for them.
The Environmental Protection Agency (EPA) intends to rescind the 2009 Endangerment Finding—a cornerstone of climate policy that has empowered federal regulation of greenhouse gas (GHG) emissions from vehicles for over 15 years. As an environmental consultant, I’ve seen firsthand how regulatory shifts like this ripple across industries, communities, and ecosystems. This proposal is no exception.
What Is the Endangerment Finding?
The 2009 Endangerment Finding was a landmark determination by the EPA that GHGs—including carbon dioxide, methane, and nitrous oxide—pose a threat to public health and welfare. This finding was based on a robust body of scientific evidence linking GHG emissions to climate change and its cascading effects: rising sea levels, extreme weather, and public health risks.
It provided the legal foundation for regulating GHG emissions under the Clean Air Act, enabling the EPA to set fuel economy and emissions standards for vehicles starting with model year 2012. These standards have helped drive innovation in cleaner technologies and reduce the carbon footprint of the transportation sector.
What’s Changing in 2025?
The EPA’s July proposal seeks to rescind the Endangerment Finding entirely. If finalized, this would eliminate the agency’s authority to regulate GHG emissions from new motor vehicles and engines. The proposal also includes repealing all existing GHG emissions standards for highway vehicles, including those already in production.
While the EPA plans to retain regulations for criteria pollutants (like nitrogen oxides and particulate matter), fuel economy labeling, and CAFE testing, the removal of GHG standards would mark a significant rollback in federal climate policy.
EPA’s Justification
The EPA argues that the Endangerment Finding is outdated and that its scientific basis should be reevaluated. The agency claims that GHG regulations have imposed burdens on manufacturers, limited consumer choice, and pushed the market prematurely toward electric vehicles.
This proposal aligns with broader deregulatory efforts under EPA Administrator Lee Zeldin, who earlier this year described the agency’s agenda as “the greatest day of deregulation our nation has seen.” Other actions include redefining the scope of the Clean Water Act and reassessing energy sector regulations.
Industry Reactions
Automakers are divided. Some welcome the rollback, citing reduced compliance costs and greater flexibility. Others worry about regulatory fragmentation, especially as states like California continue to enforce stricter standards. International manufacturers face added complexity, as they must reconcile U.S. policy with more stringent emissions rules abroad.
Legal and Public Response
Environmental groups, public health advocates, and several state governments have pledged to challenge the proposal in court. The Endangerment Finding has been upheld by the Supreme Court and lower courts, and any attempt to rescind it will likely face intense legal scrutiny.
The EPA has opened a public comment period through September 22, 2025, and scheduled hearings to gather stakeholder input. Documents related to the proposal are available on the EPA’s website and through the Federal Register.
Implications for Environmental Consulting
At PPM Consultants, we help clients understand and comply with environmental regulations. This proposal, if enacted, would shift the regulatory landscape dramatically. Companies may need to reassess their emissions strategies, reporting obligations, and sustainability goals.
For consultants, this means staying ahead of legal developments, advising clients on risk management, and helping them adapt to evolving standards. It also means advocating for science-based policy that protects public health and the environment.
Broader Context
This proposal is part of a larger trend toward deregulation in environmental governance. While proponents argue that deregulation fosters innovation and reduces costs, critics warn that it prioritizes short-term economic gains over long-term sustainability.
As consultants, we must balance these perspectives—helping clients achieve compliance and efficiency while promoting responsible environmental stewardship.
What Comes Next?
The public comment period will be crucial. Stakeholders from all sectors should engage in the process, providing data, perspectives, and concerns. Legal challenges are expected, and the final outcome may take months or even years to resolve.
Meanwhile, states with independent emissions standards will continue to lead on climate policy, potentially creating a patchwork of regulations that complicate compliance for national and global manufacturers.
Final Thoughts
The EPA’s July 2025 proposal to rescind the 2009 Endangerment Finding is more than a regulatory shift—it’s a statement about the future of climate policy in the United States. As environmental consultants, we must remain vigilant, informed, and proactive. Our role is not only to guide clients through change but also to advocate for policies that safeguard our environment and communities.
At PPM Consultants, we’re committed to helping our clients navigate this evolving landscape with clarity, compliance, and care. The decisions made in the coming months will shape the trajectory of environmental regulation for years to come—and we’ll be here to help every step of the way.
If you would like to discuss the proposed actions, please feel free to contact me at Jared.Saterfiel@ppmco.com or (318) 812-3470.