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Proposed Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act
On This Page
UPDATE-The public comment period ended June 23, 2009. The comment period was open for 60 days, following publication of the proposed rule in the Federal Register, April 24, 2009. Late comments may still be submitted on the proposed rule; however, the Clean Air Act does not require that the Environmental Protection Agency consider comments submitted past the end of the official comment period June 23, 2009, when developing the final rule. Nonetheless, we will continue to consider comments received after the close of the comment period, to the extent practicable.
Background
On April 2, 2007, in 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 held that the Administrator must determine whether or not emissions of greenhouse gases from new motor vehicles cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare, or whether the science is too uncertain to make a reasoned decision. In making these decisions, the Administrator is required to follow the language of section 202(a) of the Clean Air Act. The Supreme Court decision resulted from a petition for rulemaking under section 202(a) filed by more than a dozen environmental, renewable energy, and other organizations.
Action
You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.
The Administrator signed a proposal with two distinct findings regarding greenhouse gases under section 202(a) of the Clean Air Act:
- The Administrator is proposing to find that the current and projected concentrations of the mix of six key greenhouse gases—carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6)—in the atmosphere threaten the public health and welfare of current and future generations. This is referred to as the endangerment finding.
- The Administrator is further proposing to find that the combined emissions of CO2, CH4, N2O, and HFCs 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. This is referred to as the cause or contribute finding.
This proposed action, as well as any final action in the future, would not itself impose any requirements on industry or other entities. An endangerment finding under one provision of the Clean Air Act would not by itself automatically trigger regulation under the entire Act.
Proposed Finding
The Proposed Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act was signed on April 17, 2009. On April 24, 2009, the proposed rule was published in the Federal Register (www.regulations.gov) under Docket ID No. EPA-HQ-OAR-2009-0171:
- Proposed Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act (PDF) (26 pp, 368KB, About PDF)
Technical analyses developed in support of the Proposed Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act may be found here:
- Technical Support Document for the Proposed Findings (PDF) (171 pp, 2.8MB, About PDF)
Submitting Comments on Proposed Finding
The public comment period ended June 23, 2009. The comment period was open for 60 days, following publication of the proposed rule in the Federal Register, April 24, 2009. Late comments may still be submitted on the proposed rule; however, the Clean Air Act does not require that the Environmental Protection Agency consider comments submitted past the end of the official comment period June 23, 2009, when developing the final rule. Nonetheless, we will continue to consider comments received after the close of the comment period, to the extent practicable.
No Extension of Comment Period:
- Letter From Administrator (PDF) (2 pp, 118 KB, About PDF)
Written Comments
Written comments on the proposed finding (Docket ID No. EPA-HQ-OAR-2009-0171) may be submitted by using the following instructions:
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Instructions for Submitting Written Comments (PDF) (3 pp, 39KB, About PDF)
When providing comments, please submit them with reference to Docket ID No. EPA-HQ-OAR-2009-0171.
Public Hearings
Two public hearings were held for this proposal—on May 18, 2009 in Arlington, VA, and on May 21, 2009 in Seattle, WA. The transcript of each hearing can be found at www.regulations.gov under Docket ID No. EPA-HQ-OAR-2009-0171. The document numbers for the transcripts are EPA-HQ-OAR-2009-0171-2818 (Arlington) and EPA-HQ-OAR-2009-0171-2895 (Seattle).
Resources
- Press Release
- Overview of EPA's Proposed Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act (PDF) (2 pp, 62KB, About PDF)
- Frequently Asked Questions (PDF) (2 pp, 40KB, About PDF)
- Summary of the Science Supporting EPA’s Finding That Greenhouse Gases Threaten Public Health and Welfare (PDF) (2 pp, 54KB, About PDF)
- Massachusetts v. EPA Supreme Court Case
- Transcript of Oral Arguments, November 29, 2006 (PDF) (70 pp, 291KB, About PDF)
- Opinion of Court, April 2, 2007 (PDF) (66 pp, 508KB, About PDF)
Contact Us
For general questions about the proposed findings, please consult the Frequently Asked Questions (PDF) (2 pp, 40KB, About PDF) . If you have comments on the findings that you wish to submit to EPA, please follow the instructions for written comments above. If you have specific questions that are not covered by information on this page, you may email EPA at ghgendangerment@epa.gov or call the following number: 202-343-9927. Please remember that this email and phone number are not a forum for submitting official comments, but rather are intended only for general questions.
