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Endangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act
Resources and Tools
- Findings
- Technical Support Document
- Response to Comment Documents
- Press Release
- Resources
- Legal Basis (PDF) (1 p, 117K)
- Health Effects (PDF) (1 p, 95K)
- Environmental and Welfare Effects (PDF) (1 p, 45K)
- Climate Change Facts (PDF) (1 p, 39K)
- Light Duty Vehicle Program (PDF) (1 p, 39K)
- Timeline (PDF) (1 p, 30K)
- Denial of Petitions for Reconsideration of the Endangerment and Cause or Contribute Findings
- Frequently Asked Questions (PDF) (3 pp, 38K)
- Contact Us
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- Action
- Findings
- Response to Comments
- Resources
- Denial of Petitions for Reconsideration
- Background
- Contact Us
Action
On December 7, 2009, the Administrator signed two distinct findings regarding greenhouse gases under section 202(a) of the Clean Air Act:
- Endangerment Finding: The Administrator finds that the current and projected concentrations of the six key well-mixed 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.
- Cause or Contribute Finding: The Administrator finds that the combined emissions of these well-mixed greenhouse gases from new motor vehicles and new motor vehicle engines contribute to the greenhouse gas pollution which threatens public health and welfare.
These findings do not themselves impose any requirements on industry or other entities. However, this action is a prerequisite to finalizing the EPA's proposed greenhouse gas emission standards for light-duty vehicles, which EPA proposed in a joint proposal including the Department of Transportation's proposed CAFE standards on September 15, 2009.
Findings
These findings were signed by the Administrator on December 7, 2009. On December 15, 2009, the final findings were published in the Federal Register (www.regulations.gov) under Docket ID No. EPA-HQ-OAR-2009-0171. The final rule was effective January 14, 2010.
- Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act (PDF) (52 pp, 308K)
Technical analyses developed in support of the Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act may be found here:
- Technical Support Document for the Findings (PDF) (210 pp, 2.5MB)
Response to Comments
EPA's response to public comments received on the Proposed Findings and accompanying Technical Support Document may be found here:
- Volume 1: General Approach to the Science and Other Technical Issues Download a PDF version of Volume 1 (PDF) (69 pp, 305K)
- Appendix A. IPCC Principles and Procedures (12 pp, 48K)
- Appendix B. USGCRP/CCSP Procedures and Responsibilities (30 pp, 151K)
- Appendix C. NRC Report Development Procedures (25 pp, 4.3MB)
- Volume 2: Validity of Observed and Measured Data Download a PDF version of Volume 2 (PDF) (93 pp, 507K)
- Volume 3: Attribution of Observed Climate Change Download a PDF version of Volume 3 (PDF) (58 pp, 283K)
- Volume 4: Validity of Future Projections Download a PDF version of Volume 4 (PDF) (81 pp, 418K)
- Volume 5: Human Health and Air Quality Download a PDF version of Volume 5 (PDF) (95 pp, 557K)
- Volume 6: Agriculture and Forestry Download a PDF version of Volume 6 (PDF) (43 pp, 191K)
- Volume 7: Water Resources, Coastal Areas, Ecosystems and Wildlife Download a PDF version of Volume 7 (PDF) (65 pp, 290K)
- Volume 8: Other Sectors Download a PDF version of Volume 8 (PDF) (25 pp, 112K)
- Volume 9: Endangerment Finding Download a PDF version of Volume 9 (PDF) (37 pp, 159K)
- Volume 10: Cause or Contribute Finding Download a PDF version of Volume 10 (PDF) (18 pp, 88K)
- Volume 11: Miscellaneous Legal, Procedural, and Other Comments Download a PDF version of Volume 11 (PDF) (36 pp, 172K)
Resources
- Press Release
- Press Kit
- Legal Basis (PDF) (1 p, 117K)
- Trasfondo legal (PDF) (2 pp, 32K)
- Health Effects (PDF) (1 p, 95KB)
- Efectos a la salud (PDF) (1 p, 79K)
- Environmental and Welfare Effects (PDF) (1 p, 45K)
- Efectos medioambientales (PDF) (2 pp, 32K)
- Climate Change Facts (PDF) (1 p, 39K)
- Datos sobre el cambio climático (PDF) (2 pp, 33K)
- Light Duty Vehicle Program (PDF) (1 p, 39K)
- Timeline (PDF) (1 p, 30K)
- Frequently Asked Questions (PDF) (3 pp, 38K)
To access materials related to the proposed finding, please visit the Proposed Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act archive.
Denial of Petitions for Reconsideration
EPA denied ten Petitions for Reconsideration of the Endangerment and Cause or Contribute Findings on July 29, 2010.
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.
On April 17, 2009, the Administrator signed proposed endangerment and cause or contribute findings for greenhouse gases under Section 202(a) of the Clean Air Act. EPA held a 60-day public comment period, which ended June 23, 2009, and received over 380,000 public comments. These included both written comments as well as testimony at two public hearings in Arlington, Virginia and Seattle, Washington. EPA carefully reviewed, considered, and incorporated public comments and has now issued these final Findings.
Contact Us
Contact us at ghgendangerment@epa.gov with questions about this action.