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Fact Sheet -- Reconsideration of Former Administrator Johnson Interpretive Memo on Definition of Pollutants Covered Under the Clean Air Act


  • On September 30, 2009, the U.S. Environmental Protection Agency (EPA) proposed to reconsider the December 18, 2008 memorandum entitled “EPA’s Interpretation of Regulations that Determine Pollutants Covered by Federal Prevention of Significant Deterioration (PSD) Permit Program.” 
  • This interpretive memo, from then-EPA Administrator Stephen L. Johnson to the EPA Regional Administrators addressed when the Prevention of Significant Deterioration program would cover a pollutant, including carbon dioxide - a chief greenhouse gas.
  • The memo indicated that the Clean Air Act (CAA) Prevention of Significant Deterioration (PSD) Permitting Program would apply to pollutants that are subject to either a provision in the CAA or regulation adopted by EPA under the CAA that requires control of emissions of that pollutant. 
  • Pollutants for which EPA regulations only require monitoring or reporting were not included, such as the provisions for carbon dioxide (CO2) in the Acid Rain Program.
  • In this reconsideration proposal, EPA is requesting comment on various interpretations of when a pollutant is “subject to regulation” under the CAA for the purposes of triggering the requirements to get a PSD permit.  A PSD permit is required before a new industrial facility can be built or an existing facility can expand in a way that increases emissions. 
  • EPA is considering several interpretations of when PSD permitting requirements would be triggered including:
    • An EPA rule requiring control of emissions of a pollutant from a final national rule;
    • Inclusion of regulatory requirements for a pollutant in an EPA-approved State Implementation Plan;
    • An EPA rule requiring monitoring or reporting of emissions of a pollutant;
    • An “Endangerment Finding” for a pollutant under the Clean Air Act; and
    • EPA’s granting of a Clean Air Act section 209 waiver, such as the “California Waiver.”
  • EPA’s preferred interpretation is that an EPA rule requiring control of emissions of a pollutant from a final national rule is required to trigger PSD permitting requirements.
  • EPA also is soliciting comment on any other interpretations and issues arising from the Memo.
  • EPA is taking action to reconsider this memorandum at the same time the Agency proposes to control greenhouse gas (GHG) emissions from light duty vehicles – signed on September 15, 2009 – and to tailor the PSD permitting program to address large industrial sources of GHG emissions – which was also signed today.
  • EPA will accept comment on this proposal for 60 days after publication in the Federal Register. 


  • On April 2, 2007, the Supreme Court found that GHGs, including carbon dioxide, are air pollutants covered by the CAA.  Massachusetts v. EPA, 549 U.S. 497 (2007).  The case arose from EPA’s denial of a petition for rulemaking filed by environmental, renewable energy, and other organizations requesting that EPA control emissions of GHGs from new motor vehicles under section 202 of the CAA. 
  • The Court found that, the Administrator was required to determine whether or not emissions of GHGs 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.  This determination is known as an “endangerment finding.”
  • On August 30, 2007, EPA issued a PSD permit to Deseret Power Electric Cooperative, authorizing it to construct a new waste-coal-fired electric generating unit near its existing Bonanza Power Plant, in Bonanza, Utah.  The permit did not include emissions control requirements known as best available control technology (BACT) limits for CO2.  EPA acknowledged the Massachusetts decision but found that decision alone did not require PSD permits to include limits on CO2 emissions. 
  • Sierra Club challenged the Deseret permit.  On November 13, 2008, the Environmental Appeals Board (EAB) remanded the permit EPA to reconsider “whether or not to impose a CO2 BACT limit in light of the ‘subject to regulation’ definition under the CAA.”  The remand was based in part on EAB’s finding that there was not an established EPA interpretation of the regulatory phrase “subject to regulation.
  • On December 18, 2008, then-Administrator Johnson issued a memorandum that established an interpretation of this regulatory phrase. 
  • On December 31, 2008, Sierra Club and 14 other environmental, renewable energy, and citizen organizations petitioned EPA to reconsider the Johnson memo. 
  • On February 17, 2009, Administrator Jackson granted a Petition for Reconsideration of the December 18, 2008 memorandum and initiated a rulemaking process to solicit comment on Administrator Johnson’s memorandum and related considerations reflected in the opinion of EPA’s environmental Appeals Board in the Deseret decision.  The interpretation set forth in the December 18, 2008 memorandum remains in effect pending the reconsideration.


  • Congress established the NSR program as part of the 1977 Clean Air Act Amendments and modified it in the 1990 Amendments.  NSR is a preconstruction permitting program that serves two important purposes:
    1. Ensures the maintenance of air quality standards or, where there are not air quality standards, it ensures that air quality does not significantly worsen when factories, industrial boilers, and power plants are modified or added.  In areas that do not meet the national ambient air quality standards, NSR assures that new emissions do not slow progress toward cleaner air.  In areas that meet the standards, especially pristine areas like national parks, NSR assures that new emissions fall within air quality standards.
    2. Ensures that state-of-the-art control technology is installed at new plants or at existing plants that are undergoing a major modification.
  • At the present time, EPA does not consider CO2 or any of the other principal GHGs to be a “regulated NSR pollutant” under the definition in EPA’s federal PSD permit program regulations because there is not yet a National Rule requiring actual control.  The basis for this interpretation was expressed by former Administrator Johnson in a memorandum to the Regional Offices dated December 18, 2008, and that interpretation was not stayed by Administrator Jackson pending this reconsideration.


  • EPA will accept comment on the proposal for 60 days after publication in the Federal Register.  Comments, identified by Docket ID No. EPA-HQ- OAR-2009-0597, may be submitted by one of the following methods:
    • www.regulations.gov: Follow the online instructions for submitting comments.
    • E-mail: Comments may be sent by electronic mail (e-mail) to a-and-r-docket@epa.gov.
    • Fax:  Fax your comments to:  (202) 566-1741
    • Mail: Send your comments to: Air and Radiation Docket and Information Center, Environmental Protection Agency, Mail Code: 6102T, 1200 Pennsylvania Ave., NW, Washington, DC 20460.
    • Hand Delivery or Courier: Deliver your comments to: EPA Docket Center, 1301, Constitution Ave., NW, Room 3334, Washington, DC.  Such deliveries are only accepted during the Docket’s normal hours of operation, and special arrangements should be made for deliveries of boxed information.


  • Today's proposed action and other background information are also available electronically at http://www.regulations.gov, EPA’s electronic public docket and comment system.  The docket number for this action is Docket ID No. EPA-HQ-OAR-2009-0597.


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