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Advance Notice of Proposed Rulemaking: Regulating Greenhouse Gas Emissions under the Clean Air Act

EPA-HQ-OAR-2008-0318, July 11 2008

To view the five technical supporting documents in the docket go to http://www.regulations.gov. The document titles are:

  1. Technical Support Document - Benefits
  2. Technical Support Document - Stationary Source
  3. Draft Technical Support Document - Endangerment Analysis for Greenhouse Gas Emissions under the Clean Air Act
  4. Technical Support Document - Section 202 Greenhouse Gas Emissions
  5. Vehicle Technical Support Document - Mobile Source

The U.S. Environmental Protection Agency (EPA) is inviting comment from all interested parties on options and questions to be considered for possible greenhouse gas regulations under the Clean Air Act. EPA is issuing an advance notice of proposed rulemaking (ANPR) to gather information and determine how to proceed.

The Advance Notice

The ANPR is one of the steps EPA has taken in response to the U.S. Supreme Court's decision in Massachusetts v. EPA. The Court found that the Clean Air Act authorizes EPA to regulate tailpipe greenhouse gas emissions if EPA determines they cause or contribute to air pollution that may reasonably be anticipated to endanger public health or welfare. The ANPR reflects the complexity and magnitude of the question of whether and how greenhouse gases could be effectively controlled under the Clean Air Act.

The document summarizes much of EPA's work and lays out concerns raised by other federal agencies during their review of this work. EPA is publishing this notice at this time because it is impossible to simultaneously address all the agencies' issues and respond to the agency's legal obligations in a timely manner.

Key Issues for Discussion and Comment in the ANPR:

  • Descriptions of key provisions and programs in the CAA, and advantages and disadvantages of regulating GHGs under those provisions;
  • How a decision to regulate GHG emissions under one section of the CAA could or would lead to regulation of GHG emissions under other sections of the Act, including sections establishing permitting requirements for major stationary sources of air pollutants;
  • Issues relevant for Congress to consider for possible future climate legislation and the potential for overlap between future legislation and regulation under the existing CAA; and,
  • Scientific information relevant to, and the issues raised by, an endangerment analysis.

EPA will accept public comment on the ANPR for 120 days following its publication in the Federal Register.


In April 2007, the Supreme Court concluded that GHGs meet the CAA definition of an air pollutant. Therefore, EPA has authority under the CAA to regulate GHGs subject to the endangerment test for new motor vehicles - an Agency determination that GHG emissions from new motor vehicles cause or contribute to air pollution that may reasonably be anticipated to endanger public health or welfare.

A decision to regulate GHG emissions for motor vehicles impacts whether other sources of GHG emissions would need to be regulated as well, including establishing permitting requirements for stationary sources of air pollutants.

How to Comment

  • Comments should be identified by the following Docket ID Number: EPA-HQ-OAR-2008-0318
  • Comments should be submitted by one of the following methods:
    • www.regulations.gov: Follow the on-line instructions for submitting comments.
    • Email: a-and-r-Docket@epa.gov
    • Fax: 202-566-9744
    • Mail: Air and Radiation Docket and Information Center, Environmental Protection Agency, Mailcode: 2822T, 1200 Pennsylvania Ave., NW., Washington, DC 20460. In addition, please mail a copy of your comments on the information collection provisions to the Office of Information and Regulatory Affairs, Office of Management and Budget (OMB), Attn: Desk Officer for EPA, 725 17th St. NW., Washington, DC 20503.
    • Hand Delivery: EPA Docket Center, EPA West Building, Room 3334, 1301 Constitution Ave., NW, Washington DC, 20004. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

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