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U.S. EPA Reverses 2015 SSM SIP Policy

Posted: January 25th, 2021

Authors: Lindsey K. 

On October 9, 2020, U.S. EPA released a guidance memorandum to the 10 U.S. EPA regional administrators entitled “Inclusion of Provisions Governing Periods of Startup, Shutdown, and Malfunctions in State Implementation Plans.”  As the title implies, the memo pertains to whether certain startup, shutdown, and malfunction (SSM) provisions are acceptable in Clean Air Act (CAA) State Implementation Plans (SIPs), and is herein referred to as the 2020 SSM SIP Guidance Memo.

The 2020 SSM SIP Guidance Memo states that it “supersedes and replaces certain policy statements” from U.S. EPA’s 2015 SSM SIP Action.  The latter refers to a June 12, 2015 action in the Federal Register in which U.S. EPA restated and updated their SSM Policy applicable to SIPs.  The action was in response to a petition filed by the Sierra Club regarding how certain provisions in SIPs approved by U.S. EPA addressed excess emissions during periods of SSM.  As part of the 2015 action, U.S. EPA issued a “SIP call” to 36 states that had provisions in their SIPs that were determined to be inconsistent with this 2015 SSM SIP Policy and were therefore “substantially inadequate” and required revisions.


U.S. EPA’s 2015 SSM SIP Policy prohibited SIPs from containing provisions that allowed excess emissions during periods of SSM and/or provided for affirmative defense of those periods.  The 36 states that were issued a SIP call were determined to have U.S. EPA-approved SIPs that contained such provisions.  In response to the SIP call, states were required to submit revisions to their SIPs by November 22, 2016 to remove or otherwise address the substantially inadequate provisions.

The process for updating a SIP is neither simple nor swift.  A SIP is comprised of a state’s air regulations, and updating a SIP essentially means developing or amending one or more of the regulations included in the SIP.  That means states must determine what changes will be made, develop a proposed regulation, solicit public comments, address comments, and finalize the amendments.  The final amendments are then submitted to U.S. EPA as a proposed SIP revision.  U.S. EPA then reviews the revision and determines if it is consistent with legislative language of the CAA.  If so, U.S. EPA issues a proposal to approve the SIP revision.  If U.S. EPA determines that the SIP revision (or part of the SIP revision) is not acceptable, U.S. EPA issues a proposal to disapprove (or partially disapprove) the SIP revision.  The proposals for approval or disapproval are published in the Federal Register and are subject to their own public comment period.  After addressing comments, U.S. EPA will issue a final approval or disapproval.  If disapproved, the state must again go through the state rulemaking process to further amend the applicable provisions.


The 2020 SSM SIP Guidance Memo “supersedes the 2015 SSM SIP policy on exemption and affirmative defense provisions.”  U.S. EPA explains in the memo that the basis for the 2015 SSM SIP Policy was the D.C. Circuit Court’s 2008 decision in favor of another Sierra Club petition, in which the court determined that SSM exemptions were not permitted in 40 CFR Part 63 National Emission Standards for Hazardous Air Pollutant (NESHAP) regulations.  However, the authority for NESHAP regulations is under Section 112 of the CAA, while the authority for SIPs is under Section 110 of the CAA.  Sections 110 and 112 of the CAA serve different purposes and are implemented differently.  The purpose of Section 110 is to protect the National Ambient Air Quality Standards (NAAQS) and the plan to maintain compliance with the NAAQS is implemented by each state (i.e., the SIP), whereas the purpose of Section 112 is to regulate hazardous air pollutants and is implemented by U.S. EPA.  Therefore, U.S. EPA concludes in the 2020 SSM SIP Guidance Memo that the 2008 court decision on Section 112 NESHAPs should not be applied to Section 110 SIPs.  Consequently, SSM exemptions and affirmative defense provisions in SIPs may be acceptable in certain circumstances, such as when the SIP as a whole is protective of the NAAQS.

While the 2020 SSM SIP Guidance Memo reverses the SSM exemption and affirmative defense prohibitions of the 2015 SSM SIP Policy, it does not reverse the determinations of substantial inadequacy resulting in the SIP call.  Rather, U.S. EPA states that it “plans to continue its review of each of the SIP calls issued in 2015” and “consider whether any particular SIP call should be maintained, modified, or withdrawn.”


State SIP revisions in response to the 2015 SIP call are in various stages of approval.  Some states have amended their rules, submitted SIP revisions, and had them approved by U.S. EPA, while others submitted SIP revisions but have not yet received approval from U.S. EPA, or did not submit SIP revisions at all.  The states and specific SIP provisions that were subject to a SIP call are listed in the 2015 Federal Register notice.  The status of a SIP’s approval can be found at 40 CFR Part 52.

While U.S. EPA’s intent as presented in the 2020 SSM SIP Guidance Memo is to review each state’s 2015 SIP call, U.S. EPA Regional Offices have acted on SIPs for certain states prior to the October 9, 2020 publication, as early as 2018 when U.S. EPA Region 6 agreed to reconsider the 2015 Texas SIP call.  The withdraw was finalized on January 7, 2020.  U.S. EPA Region 4 proposed to withdraw the 2015 North Carolina SIP call in 2019, subsequently finalizing the withdraw on April 2, 2020.  Most recently, U.S. EPA Region 7 proposed to withdraw the 2015 Iowa SIP call in June 2020, and finalized the withdraw on October 23, 2020, shortly after publication of the 2020 SSM SIP Guidance Memo, noting the change in national policy as further support for the action.  Iowa had not submitted a SIP revision in response to the 2015 SIP call, so U.S. EPA’s withdraw of the SIP call essentially wiped the slate clean.  For other states that have gone through the rulemaking process, the next steps are not as clear (or concise), as states would need to go through the rulemaking process again to reverse the changes.  As described earlier, the rulemaking process is not just the flip of a switch.

It’s important to note that states are not required to revise their SIP based on the 2020 SSM SIP Guidance Memo.  If a state wants to maintain the elimination of SSM exemptions and affirmative defense provisions in its SIP, the state is within its rights to do so under the CAA.  In fact, states with limited resources to revise a SIP may resist initiating the process to address the 2020 SSM SIP Guidance Memo unless prompted by stakeholders.  The 2021 change in U.S. EPA administration could also prompt another review of this guidance.

Finally, while the basis for the change in U.S. EPA’s interpretation is the difference between CAA Section 110 and Section 112, some overlap exists between the pollutants addressed by each section.  In particular, NAAQS pollutants such as particulate matter (PM) and carbon monoxide (CO) are often surrogates for HAPs in 40 CFR Part 63 NESHAPs.  Thus, a SIP could allow for SSM exemptions and affirmative defense for excess emissions of a NAAQS pollutant, but a facility might not see the same relief if that pollutant is also subject to a 40 CFR Part 63 NESHAP limitation.

Expect to see more SIP-related actions in 2021 and beyond as U.S. EPA continues its review of each state’s SIP call.  If you have any questions about this topic, or want to understand where your particular state stands, please contact me at lkroos@all4inc.com or 610.933.5246 x122.


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