Technical Support Document - Sections 110(a)(2)(C), 110(a)(2)(D)(i)(II) (Prong 3) and 110(a)(2)(J) related to Prevention of Significant Deterioration (PSD) for Mississippi
	Section 110(a)(2)(C) has three components that must be addressed in infrastructure SIP submissions: enforcement, state-wide regulation of new and modified minor sources and minor modifications of major sources; and PSD permitting of major sources and major modifications in areas designated attainment or unclassifiable for the subject national ambient air quality standard (NAAQS) as required by CAA title I part C (i.e., the major source PSD program).  
	Section 110(a)(2)(D)(i) has two components:  110(a)(2)(D)(i)(I) and 110(a)(2)(D)(i)(II).  Each of these components have two subparts resulting in four distinct components, commonly referred to as "prongs," that must be addressed in infrastructure SIP submissions.  The first two prongs, which are codified in section 110(a)(2)(D)(i)(I), are provisions that prohibit any source or other type of emissions activity in one state from contributing significantly to nonattainment of the NAAQS in another state ("prong 1"), and interfering with maintenance of the NAAQS in another state ("prong 2").  The third and fourth prongs, which are codified in section 110(a)(2)(D)(i)(II), are provisions that prohibit emissions activity in one state from interfering with measures required to prevent significant deterioration of air quality in another state ("prong 3"), or to protect visibility in another state ("prong 4"). 
	Section 110(a)(2)(J) has four components that must be addressed in infrastructure SIP submissions:  1) consultation with government officials, 2) public notification, 3) prevention of significant deterioration, and 4) visibility protection.  
      With respect to the PSD elements of 110(a)(2)(C) and (J), EPA interprets the CAA to require each state to make, for each new or revised NAAQS, an infrastructure SIP submission that demonstrates that the air agency has a complete PSD permitting program meeting the current requirements for all regulated new source review (NSR) pollutants.  The requirements of element 110(a)(2)(D)(i)(II) may also be satisfied by demonstrating the air agency has a complete PSD permitting program correctly addressing all regulated NSR pollutants.
The PSD Program Requirements for Infrastructure SIPs
      In order for the PSD elements of infrastructure SIP submissions to be approvable, a state's submission must demonstrate that all structural PSD program elements that are currently due under the CAA and EPA regulations are either approved into the SIP or are submitted for approval, in which case EPA must take final action to approve these elements before or simultaneously with its action on the infrastructure SIP.  There are four more recent structural PSD program requirements that are relevant to EPA's review of the PSD elements of the infrastructure SIP submissions. The EPA regulations that require these SIP revisions are:  1) the Phase II Rule; 2) the Greenhouse Gas (GHG) Tailoring Rule as consistent with the holding in Utility Air Regulatory Group v. Environmental Protection Agency; 3) the NSR Fine Particulate Matter (PM2.5) Rule; and 4) the PM2.5 PSD Increment-Significant Impact Levels (SILs)-Significant Monitoring Concentrations (SMC) Rule (only as it relates to PM2.5 Increments).  Specific details on these PSD requirements can be found in the respective final rules cited above, however, a brief summary of each rule is provided below.  
      The Phase II rule established Federal NSR permitting requirements for the implementation of the ozone NAAQS including recognizing nitrogen oxide as an ozone precursor.  See 70 FR 71612.
      The GHG Tailoring Rule established emission thresholds for determining which new stationary sources and modification projects become subject to PSD permitting requirements for their GHG emissions.  See 75 FR 31514.  EPA notes that on June 23, 2014, the United States (U.S.) Supreme Court issued a decision addressing the application of PSD permitting requirements to GHG emissions.  See Utility Air Regulatory Group v. Environmental Protection Agency, 134 S. Ct. 2427.  In that decision, the Supreme Court said that the EPA may not treat GHGs as an air pollutant for purposes of determining whether a source is a major source required to obtain a PSD permit.  The Court also said that the EPA could continue to require that PSD permits, otherwise required based on emissions of pollutants other than GHGs, contain limitations on GHG emissions based on the application of Best Available Control Technology (BACT).
      In accordance with the Supreme Court decision, on April 10, 2015, the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit) issued an Amended Judgment (Coalition for Responsible Regulation, Inc. v. EPA, Nos. 09-1322, 10-073, 10-1092 and 10-1167), vacating the regulations that implemented Step 2 of EPA's GHG Tailoring Rule, but not the regulations that implement Step 1 of that rule.  Step 1 of the GHG Tailoring Rule covers sources that are required to obtain a PSD permit based on emissions of pollutants other than GHGs.  Step 2 applied to sources that emitted only GHGs above the thresholds triggering the requirement to obtain a PSD permit.  The Amended Judgment preserves, without the need for additional rulemaking by the EPA, the application of the BACT requirement to GHG emissions from Step 1 or "anyway" sources.  With respect to Step 2 sources, the D.C. Circuit's Amended Judgment vacated the regulations at issue in the litigation, including 40 CFR 51.166(b)(48)(v) and 40 CFR 52.21(b)(49)(v), "to the extent they require a stationary source to obtain a PSD permit if greenhouse gases are the only pollutant (i) that the source emits or has the potential to emit above the applicable major source thresholds, or (ii) for which there is a significant emission increase from a modification."  The D.C. Circuit simultaneously issued its mandate, which means that the Coalition Amended Judgment became final and effective upon issuance.
      On August 12, 2015, EPA signed a final rule that removes from the PSD regulations certain regulatory provisions that require a stationary source to obtain a PSD permit solely on the basis of the source's GHG emissions (Step 2) and the regulations that require the EPA to consider further phasing in GHG permitting requirements into the PSD.  The EPA intends to further revise the PSD regulations to fully implement the Coalition Amended Judgment in a separate rulemaking.  States may submit revisions to their PSD SIP program consistent with EPA's amended regulations whenever feasible.  At this juncture, EPA is not expecting states to have revised their PSD programs for purposes of infrastructure SIP submissions and is only evaluating such submissions to assure that the state's program correctly addresses GHGs consistent with the court decisions discussed above and EPA's revised regulations.
      The 2008 NSR PM2.5 Rule and 2010 PM2.5 PSD Increment-SILs-SMC Rule (only as it relates to PM2.5 Increments) established NSR permitting requirements for the implementation of the PM2.5 NAAQS including increments pursuant to section 166(a) of the CAA to prevent significant deterioration of air quality in areas meeting the NAAQS.  See 73 FR 28321 and 75 FR 64864.  On January 22, 2013, the D.C. Circuit, in Sierra Club v. EPA, 703 F.3d 458 (D.C. Cir. 2013), issued a judgment that, among other things, vacated the provisions adding the PM2.5 SMC to the Federal regulations, at 40 CFR 51.166(i)(5)(i)(c) and 52.21(i)(5)(i)(c), that were promulgated as part of the 2010 PM2.5 PSD Increment-SILs-SMC Rule.  See 75 FR 64864; see also, Sierra Club v. EPA, 703 F.3d 458 (D.C. Cir. 2013).  In its decision, the court held that EPA did not have the authority to use SMCs to exempt permit applicants from the statutory requirement in section 165(e)(2) of the CAA that ambient monitoring data for PM2.5 be included in all PSD permit applications.  Thus, although the PM2.5 SMC was not a required element of a state's PSD program and thus not a structural requirement for purposes of infrastructure SIPs, were a SIP-approved PSD program that contains such a provision to use that provision to issue new permits without requiring ambient PM2.5 monitoring data, such application of the SIP would be inconsistent with the court's opinion and the requirements of section 165(e)(2) of the CAA.  
      EPA approved the SMC's into the Mississippi SIP on September 26, 2012 (77 FR 59095).  However, given the clarity of the court's decision, it would now be inappropriate for Mississippi to continue to allow applicants for any pending or future PSD permits to rely on the PM2.5 SMC in order to avoid compiling ambient monitoring data for PM2.5.  Because of the vacatur of the EPA regulations, the SMC provisions, included in Mississippi's SIP-approved PSD program on the basis of EPA's regulations, are unlawful and no longer enforceable by law.  Permits issued on the basis of these provisions as they appear in Mississippi's federally-approved SIP would be inconsistent with the CAA and difficult to defend in administrative and judicial challenges.  Thus, the SIP provisions may not be applied even prior to their removal from the SIP.  Mississippi should instead require applicants requesting a PSD permit, including those having already been applied for but for which the permit has not yet been received, to submit ambient PM2.5 monitoring data in accordance with the CAA requirements whenever either direct PM2.5 or any PM2.5 precursor is emitted in a significant amount.
      On December 9, 2013, EPA issued a final rulemaking to remove the vacated and remanded PM2.5 SILs and the vacated PM2.5 SMC provisions from 40 CFR 51.166 and 52.21.  See 79 FR 73698.  Because the Court vacated the PM2.5 SMC provisions in 40 CFR 51.166(i)(5)(i)(c) and 52.21(i)(5)(i)(c), EPA revised the existing concentration for the PM2.5 SMC listed in sections 51.166(i)(5)(i)(c) and 52.21(i)(5)(i)(c) to zero micrograms per cubic meter (mg/m[3]).  Were EPA to completely remove PM2.5 from the list of pollutants in sections 51.166(i)(5)(i)(c) and 52.21(i)(5)(i)(c) of the PSD regulations, PM2.5 would no longer be a listed pollutant.
      EPA did not entirely remove PM2.5 as a listed pollutant in the SMC provisions so as to avoid any potential that sections 51.166(i)(5)(iii) and 52.21(i)(5)(iii) could be interpreted as giving reviewing authorities the discretion to exempt permit applicants from the requirement to conduct monitoring for PM2.5.  Such a conclusion would contravene the Court's decision and the CAA.
      By continuing to include PM2.5 as a pollutant in the list contained in sections 51.166(i)(5)(i) and 52.21(i)(5)(i), with the numerical value replaced with zero mg/m[3], EPA is avoiding any concern that paragraph (iii) of the two affected sections could be applied to excuse permit applicants from adequately addressing the monitoring requirement for PM2.5.
      EPA also advises states to begin preparations to remove the PM2.5 provisions from their state PSD regulations and SIPs.  As the previously-approved PM2.5 SMC SIP provisions are no longer enforceable, EPA does not believe the existence of these provisions in SIPs preclude approval of the infrastructure SIP submissions.
      EPA also advises states to begin preparations to remove the PM2.5 provisions from their state PSD regulations and SIPs.  As the previously-approved PM2.5 SMC provisions in the Mississippi SIP are no longer enforceable, EPA does not believe the existence of these provisions in the State's implementation plan precludes approval of the infrastructure SIP submission for Mississippi.

EPA's Analysis of How Mississippi Addressed Sections 110(a)(2)(C), 110(a)(2)(D)(i)(II)(prong 3), and 110(a)(2)(J) related to PSD
      Described below is EPA's analysis of how the Mississippi infrastructure SIP submission meets the requirements of the PSD elements for the NAAQS for which it was submitted.  This analysis includes review of the EPA's previous approval of the four structural PSD program requirements which is summarized in Table 1 below.  
   Table 1. EPA-Approved Structural PSD Program Requirements for Mississippi
                                     State
                                 Phase II Rule
                              GHG Tailoring Rule
                                NSR PM2.5 Rule
                       PM2.5 PSD Increment-SILs-SMC Rule
                                  Mississippi
                               December 20, 2010
                                 (75 FR 79300)
                 December 29, 2010              (75 FR 81858)
                       September 26, 2012 (77 FR 59095)
                       September 26, 2012 (77 FR 59095)

