In September, the Oregon Department of Environmental Quality submitted formal comments to the U.S. Environmental Protection Agency fiercely opposing its proposal to revoke the Endangerment Finding and weaken motor vehicle emission standards.
In 2009, the EPA established the “Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act,” which determined climate change is caused by air pollution from human activity and a danger to human health. That decision is a cornerstone of U.S. climate policy and has provided the scientific and legal foundation for regulating greenhouse gas emissions under the Clean Air Act. It became the basis on which many greenhouse gas emissions standards have been developed and continues to play an important role in achieving Oregon’s climate goal to reduce emissions from transportation to 80% below 1990 levels by 2050.
“We know greenhouse gas emissions from transportation are approximately 35% of total emissions across the state. It is the largest sector contributing those emissions and a major source of climate change,” said Oregon DEQ Director Leah Feldon. “Clean Fuels, Climate Protection and Oregon Clean Vehicle Rebates are just a few of the many programs DEQ has developed to reduce greenhouse gas emissions based on standards resulting from the EPA’s landmark 2009 decision. We rely on the federal government to set strong national standards which lay the groundwork for us to fight both climate change and local air pollution and keep our communities safe and healthy.”
The EPA’s current proposal follows the recent release of a report from the U.S. Department of Energy’s Climate Working Group titled, “A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate.” The document has been widely criticized by climate scientists for its mischaracterization of evidence and movement away from established scientific norms. Over the last couple of months, Oregon DEQ testified at the EPA’s public hearing and submitted written comments challenging the research and conclusions resulting from that report.
“The Endangerment Finding is not political; it is based on overwhelming scientific research and confirmed by the Supreme Court,” said Oregon Gov. Tina Kotek. “To take away the Endangerment Finding puts Oregon’s climate plan at risk, weakens years of progress towards reducing greenhouse gases, and makes communities, especially those near highways and high-traffic commercial routes, even more vulnerable to air pollution, heat waves, and more dangerous climate events.”
In addition, the National Academies of Sciences, Engineering, and Medicine issued a new report in mid-September. It is a review and confirmation of the hazardous health impacts resulting from human-caused climate change.
Oregon DEQ has compiled several resources below, so you can read more about the Endangerment Finding, the science behind it, and why it’s crucial to Oregon’s path toward reducing greenhouse gases, slowing climate change, and breathing cleaner air.
Resources:
- Oregon DEQ: “Written Comments in Opposition to Reconsideration of 2009 Endangerment Finding and Greenhouse Gas Vehicle Standards (EPA Proposal),” submitted Sept. 19, 2025
- Oregon DEQ: “Comments Opposing the U.S. Department of Energy’s Climate Working Group Report,” submitted Sept. 2, 2025
- U.S. Department of Energy Climate Working Group: A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate, report, July 23, 2025
- National Academies of Sciences, Engineering, and Medicine: National Academies Publish New Report Reviewing Evidence for Greenhouse Gas Emissions and U.S. Climate, Health, and Welfare, press release, Sept. 17, 2025
- California Air Resources Board: “CARB submits scathing critique of U.S. EPA’s illegal effort to overturn the endangerment finding,” press release, Sept. 22, 2025
By Susan C. Mills, Oregon DEQ public affairs specialist