Our right to clean air is at stake.

The 2009 Endangerment Finding is the cornerstone of the United States’ legal and regulatory framework for addressing climate change under the Clean Air Act. 

In the 2007 case, Massachusetts v. EPA, 549 U.S. 497 (2007), the Supreme Court found that greenhouse gases are air pollutants covered by the Clean Air Act. The Court directed the EPA to determine whether greenhouse gas emissions from new motor vehicles caused or contributed to “air pollution that may reasonably be anticipated to endanger public health or welfare, or whether the science is too uncertain to make a reasoned decision.” 

During the next two years, the EPA undertook a scientific assessment of the effects of greenhouse gases.  

This final action has two distinct “findings,” which are:

1. The “Endangerment Finding,” in which the EPA found that the mix of atmospheric concentrations of six key, well-mixed greenhouse gases threatens both the public health and the public welfare of current and future generations. 
2. These six greenhouse gases are: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). These greenhouse gases in the atmosphere constitute the “air pollution” that threatens both public health and welfare. 
3. The “Cause or Contribute Finding,” in which the EPA found that the combined greenhouse gas emissions from new motor vehicles and motor vehicle engines contribute to the atmospheric concentrations of these key greenhouse gases and hence to the threat of climate change. 

(Source: https://www.epa.gov/sites/default/files/2016-08/documents/endangermentfinding_faqs.pdf)

Source: https://www.epa.gov/climate-change/greenhouse-gas-endangerment-finding-timeline 

As the NRDC states “Repealing the Endangerment Finding and climate protection standards for vehicles, power plants, and other industries would violate our nation’s clean air laws and betray public trust.”  Without a doubt, repealing the Endangerment Finding will go even further than that, though. 

The Endangerment Finding underpins the Federal Government’s authority to protect our planet’s health and wellbeing, too. Without it, greenhouse gas regulations will fall away. Emissions will increase–exacerbating the effects of climate change–and air pollution will worsen. We do not have time to waste.

These findings serve as a prerequisite to regulate greenhouse gas emissions under the Clean Air Act. It is a declaration that greenhouse gases from human activities endanger public health and welfare, which then grants the EPA the legal authority to set and enforce standards to address the threat. 

If the Endangerment Finding is repealed, the EPA will lack the legal basis to establish rules for these six air pollutants.

Call to Action: Oppose the EPA’s Proposal to End the Regulation of Greenhouse Gases

Oppose the EPA’s proposal to repeal the Endangerment Finding by: (1) submitting written comments; (2) participating in public hearings on August 19-20; (3) engaging in legal advocacy; and (4) contacting your elected officials. Written comments are due by September 15, 2025!

1. Submit a Public Comment

Find the docket: Go to https://www.regulations.gov/document/EPA-HQ-OAR-2025-0194-0093   (Docket ID No. EPA-HQ-OAR-2025-0194). Read the Proposed Rule to inspire your Public Comment!

Formulate your thoughts: Express your views on the proposed repeal! You can write your comment online in the provided box, or get fancy and submit a pdf attachment of your letter. 

Include in your submission:

• Address your submission to:

• Subject line that includes: Docket ID No. EPA-HQ-OAR-2025-0194
• Your points for consideration. Feel free to Google the point headings below to find articles and news to inspire your thoughts!
  • Here are points you may consider including:
    • Effects of Identified Pollutants: The six specific greenhouse gases (pollutants) are considered a danger. Why are they dangerous?
      • NRDC: Greenhouse Effect 101
      • EDF: The science behind the Endangerment Finding 
    • Basis for the Finding: References the scientific evidence supporting the conclusion that these pollutants threaten public health and welfare. The science is STRONG!
      • Simply Google: what causes climate change
      • Climate change worsens air pollution, extreme weather, expert says
      • EPA’s Endangerment Finding: Technical Support Document
      • The UN: Causes and Effects of Climate Change
      • The UN: What Is Climate Change?
      • NASA: The Causes of Climate Change
    • Definition of Harm: The anticipated negative impacts on public health and welfare due to the pollutants are described (e.g., air quality issues, extreme weather, threats to vulnerable groups). Have you, someone you love, or your community been affected by an extreme weather event (e.g., hurricanes or floods) or air pollution (e.g., asthma or cardiac problems)?
    • Time Horizon: Indicates that the endangerment affects both current and future generations. Got something to say about that?
    • Who this proposal affects: EVERYONE. Climate change knows no borders. Air pollution knows NO borders. Both of these issues affect everyone, globally. Your personal story matters. This Public Comment MUST include the voices of the masses, not only scientists and climate experts.
      • EDF: How the Trump administration is attacking limits on planet-warming pollution, putting us in danger
• DO NOT use profanity.
• DO NOT include personal information in your comment’s text unless you’re cool with it being online for all to see.
  • More questions on the rules? See this guidance.

Please, DO NOT copy these points word for word. Submissions that are too similar may be thrown out and, therefore, not considered. 

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Administrator Lee Zeldin

Environmental Protection Agency (EPA)

1200 Pennsylvania Avenue NW

Washington, D.C. 20460

Subject: Docket ID No. EPA-HQ-OAR-2025-0194 Reconsideration of the 2009 Endangerment Finding for Greenhouse Gases under Section 202(a) of the Clean Air Act

Dear Administrator Zeldin,

This letter addresses concerns regarding the reconsideration of the EPA’s Endangerment Finding for greenhouse gases (GHGs) under Section 202(a) of the Clean Air Act. The 2009 finding concluded that:

The “Endangerment Finding,” in which the EPA found that the mix of atmospheric concentrations of six key, well-mixed greenhouse gases threatens both the public health and the public welfare of current and future generations. These six greenhouse gases are: carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). These greenhouse gases in the atmosphere constitute the “air pollution” that threatens both public health and welfare. 

The “Cause or Contribute Finding,” in which the EPA found that the combined greenhouse gas emissions from new motor vehicles and motor vehicle engines contribute to the atmospheric concentrations of these key greenhouse gases and hence to the threat of climate change. 

Source: https://www.epa.gov/sites/default/files/2016-08/documents/endangermentfinding_faqs.pdf 

[YOUR POINTS HERE. See Senate Democrats Letter to EPA on Endangerment Finding for another example.]

I urge you to [What do you want the EPA to do?]. 

[Closing statement] I support decisions grounded in science that promote the well-being of the American people.

Thank you.

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All comments must be submitted by September 15, 2025!

Old school and prefer to write a letter?

• Mail: U.S. Environmental Protection Agency, EPA Docket Center, OAR, Docket EPA-HQ-OAR-2025-0194, Mail Code 28221T, 1200 Pennsylvania Avenue NW, Washington, DC 20460.
• Hand Delivery or Courier (by scheduled appointment only): EPA Docket Center, WJC West Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. The Docket Center’s hours of operations are 8:30 a.m.–4:30 p.m., Monday–Friday (except federal holidays).

2. Attend a Public Hearing 

Virtual hearings are scheduled for August 19-20, 2025.

• Register for the hearing: The hearing notice, registration information, and any updates to the hearing schedule will also be available at https://www.epa.gov/regulations-emissions-vehicles-and-engines/proposed-rule-reconsideration-2009-endangerment-finding. Please refer to this website for any updates regarding the hearings. 

3. Pursue Legal Avenues 

Work with advocacy groups: Organizations like Earthjustice and the Sierra Club are planning to challenge the repeal in court after the comment period closes, according to Earthjustice and ABC News.

Support litigation: You can support these legal efforts through donations or by participating in campaigns to pressure lawmakers.

4. As Always, Contact Your Representatives!

Send your comment to your representatives, too. Emplore your elected officials in the House of Representatives and the Senate to oppose the repeal and support the protection of climate regulations.

• Who is my U.S. House Representative? 
• Who is my Senator? 

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further reading:

• Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act
• EPA Releases Proposal to Rescind Obama-Era Endangerment Finding, Regulations that Paved the Way for Electric Vehicle Mandates
• EPA’s Endangerment Finding: The Legal and Scientific Foundation for Cutting Climate-Changing Pollution
• Technical Support Document

Let us know here on our contact page or DM us on Instagram when you’ve submitted your comment!