**Technical Support Document -**  **Sections 110(a)(2)(C),**  **110(a)(2)(D)(i)(II) (**  **Prong 3 )**  **and**

**110(a)(2)(J) related to P revention of**  **S ignificant**  **D eterioration (PSD)**  **for Mississippi** Section 110(a)(2)(C) has three components that must be addressed in infrastructure SI P 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 b y CAA title Ipart 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 re sulting 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 t ype 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 s ection 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 anothe r state (“prong 3”), or to protect visibility in another state (“p rong 4”). Section 110(a)(2) (J) has four components that must be addressed in infrastructure SIP submissions: 1) c onsultation with government officials , 2) p ublic notification , 3) prevention of significant deterioration, and 4) v isibility protection
. With respect to the PSD e lements 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 SI P submission that demonstrates that the air agency has a complete PSD permitting program meet ing the currentrequirements for all regulated new source review (NSR) pollutants. The requirements of e lement

110(a)(2)(D)(i)(II) may

also be satisfied by

demonstrating the air agency has a complete PSD permitting program correctly addressing all regulat ed NSR pollutants.
**T he PSD P**  **rogram 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 currentl y 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 SI P. T here are four more re cent structural PSD program requirements that are relevant to EPA’s r eview of the PSD e lements of the infrastructure SI P submissions
. The EPA regulations that require these SIP revisions are: 1) the Phase II Rule 1 ; 2) the Greenhouse Gas (GHG) Tailoring Ru le 2 as consistent with the holding in Utility Air Regulatory Group v. Environmental Protection Agency ; 3 3) the NSR Fine Particulate Matter ( PM 2.5 ) Rule 4 ; and 4) the PM 2.5 PSD Increment - Significant Impact Levels ( SILs )
- Significant Monitoring Concentrations ( SMC ) Rule (only as it relates to PM 2.5 In crements)
. 5

1 “ Final Rule To Implement the 8
- Hour Ozone National Ambient Air Quality Standard

—Phase 2; Final Rule” (November 29, 2005, 70 FR 71612) (hereafter referred to as the “Phase II Rule”)
. 2 Prevention of Significant Deterioration and Title V Greenhouse Gas (GHG) Tailoring Rule; Final Rule” (June 3, 2010, 75 FR 31514) (hereafter referred to as the “GHG Tailoring Rule ”).
3 Utility Air Regulatory Group v. Environmental Protection Agency , 134 S. Ct. 2427 (2014).
4 Implementation of the Ne w Source Review Program for Particulate Matter Less Than 2.5 Micrometers; Final Rule” (May 16, 2008, 73 FR 28321) (hereafter referred to as the “NSR PM 2.5 Rule” ).
5 “Final Rule on the Prevention of Significant Deterioration (PSD) for Particulate Matter Less Than 2.5 Micrometers (PM 2.5 )

– Increments, Significant Impact Levels (SILs) and Significant monitoring Concentration (SMC); Final Rule” (October 20, 2010, 75 FR 64864) (hereafter referred to as the“PM 2.5 PSD Increment
- SILs
- SMC Rule (only as it relates to PM 2.5 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 F ederal NSR p ermitting 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 modificat ion projects become subject to PSD permitting requ irements for their GHG emissions. See 75 FR 31514
. EPA notes that o n 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. Inthat decision, the Supreme Court said that the EPA may n ot 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, o n 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
s ources 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 therequireme nt to obtain a PSD permit. The Amended Judgment preserves, without the need for

additional rulemaking b y the EPA, the application of the BACT requirement to GHG emissions from Step 1 or “an yw ay ” 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 so urce’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
se parate rulemaking. States may submit revisions to their PSD SI P 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 SI P submi ssions and is only evaluating such submissions to assure that the state’s program correctl y addresses GHGs consistent with the court decisions discussed above and EPA’s revised regulations
. The 2008 NSR PM 2.5 Rule 6 and 2010 PM 2.5 PSD Increment - SILs
- SMC Rule (only as it relates to PM 2.5 In crements) established NSR permitting requirements for the implementation of

6 On January 4, 2013, the U.S. Court of Appeals, in Natural Resources Defense Council v. EPA , No. 08
- 1250, 2013 WL 45653 (D.C. Cir., filed Ju ly 15, 2008) (consolidated with 09
- 1102, 11
- 1430), issued a judgment that remandedthe PM 2.5 NAAQS including increments pursuant to section 166(a) of the CAA to prevent

significant deterioration of air qualit y in areas meeting the NAAQS
. See 73 FR 28321 and 75 FR 64864 . O n 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 PM 2.5 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 PM 2.5 PSD Increment - SI Ls
- SMC Rule. 7 See 75 FR 64864 ; s ee 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 PM 2.5 be included in all PSD permit a

pplications. Thus, although the PM 2.5 SMC was not a required element of a
s tate ’ s PSD program and thus not a structural requirement for purposes of infrastructure SI Ps, were a SI P
- approved PSD program that contains such a provision to use that provision to issue
EPA’s 2007 and 2008 rules implementing the PM 2.5 NAAQS. The court concluded that since subpart 4 of the CAA generally applies to coarse particulate matter ( PM 10 ) , EPA shoul d have also follow ed the more prescriptive subpart 4 structure for the PM 2.5 im plementation rules. The court ordered EPA to repromulgate the implementation rules pursuant to subpart 4. Subpart 4 of p art D, t itle 1 of the CAA establishes additional provisions for particulate matter nonattainment areas. The 2008 implementation rule addressed by the court decision, “Implementation of New Source Review (NSR) Program for Particulate Matter Less Than 2.5 Micrometers (PM 2.5 ),” 73 FR 28321 (May 16, 2008), prom ulgated NSR requirements for implementation of PM 2.5 in both nonattainment areas (NNSR) and attainment/unclassifiable areas (PSD). As the requirements of s ubpart 4 only pertain to nonattainment areas, EPA does not consider the portions of the 2008 rul e that address requirements for PM 2.5 attainment and unclassifiable areas to be affected by the court’s opinion. Moreover, EPA does not anticipate the need to revise any PSD requirements promulgated in the 2008 rule in order to comply with the court’s dec ision. Accordingly, EPA’s approval of a state’s infrastructure SIP related to elements (C), (D)(i) (prong 3) , or (J) with respect to the PSD requirements promulgated in the 2008 NSR PM 2.5 Rule does not conflict with the court’s opinion. The court’s decision with respect to the NNSR requirements promulgated by the 2008 implementation rule also does not affect EPA’s action on the present infrastructure action s . EPA interprets the Act to exclude nonattainment area requirements, including re quirements associated with a nonattainment NSR program, from infrastructure SIP submissions due three years after adoption or revision of a NAAQS . Instead, these elements are typically referred to as nonattainment SIP or attainment plan elements, which wo uld be due by the dates statutorily prescribed under subpart 2 through 5 under part D, extending as far as 10 years following designations for some elements
. 7 “ Prevention of Significant Deterioration (PSD) for Particulate Matter Less Than 2.5 Micromet ers (PM 2.5 )

— Increments, Significant Impact Levels (SILs) and Significant Monitoring Concentration (SMC) ” ; Final Rule, 75 FR 64864 (October 20, 2010) , (hereafter referred to as the “ 2010 PM 2.5 PSD Increment
- SILs
- SMC Rule ”).new permits without requiring ambient PM 2.5 monitoring data, such application of the SI P 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, g iven the clarit y 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 PM 2.5 SMC in order to avoid compiling ambient monitoring data f or PM 2.5 . 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 federall y - approved SIP would be inconsistent with the CAA and difficult to defend in administrative and judicial challenges. T hus, 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 alread y been applied for but for which the permit has not yet been received, to submit ambient PM 2.5 monitoring data in accordance with the CAA requirements whenever either direct PM 2.5 or any

PM 2.5 precursor is emitted in a significant amount. 8 On December 9, 2013, EPA issued a final rulemaking to remove the vacated and remanded PM 2.5 SILs 9 and the vacated PM 2.5 SMC provisions from 40 CFR 51.166 and 52.21. 10

8 In lieu of the applicants’ need to set out PM 2.5 mo nitors to collect ambient data, applicants may submit PM 2.5 am bient data collected from existing monitoring networks when the permitting authority deems such data to be representative of the air quality in the area of concern for the year preceding receipt of the application. EPA believes that applicants will generally be able to rely on existing representative monitoring data to satisfy the mo nitoring data requirement.
9 The court’s January 22, 2013, d ecision also vacated and remanded back to EPA the PM 2.5 SILs. EPA’s December 9, 2013 , final rule also removed the PM 2.5 SILs from the CFR. The PM 2.5 SILs are not a required element of a s tate’ s PSD program and thus not a structural requirement for purpos es of infrastructure SIPs . The PM 2.5 SILs are not approved into the SIP revision that is the subject of this proposed rulemaking. 10 Final Rule entitled “ Prevention of Significant Deterioration for Particulate Matter Less Than 2.5 Micrometers

— Significant Impact Levels and Significant Monitoring Concentration: Removal of Vacated Elem ents;” 79 FR 73698 (December 9, 2013)
.See 79 FR 73698. Because the Court vacated the PM 2.5 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 PM 2.5 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 PM 2.5 from the list of pollutants in sections 51.166(i)(5)(i)( c ) and 52.21(i)(5)(i)( c ) of the PSD regulations, PM 2.5 would no longer be a listed pollutant
. EPA did not entirely

remove PM 2.5 as a listed pollutant in the SMC provisions so as to avoid an y 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 PM 2.5 . Such a conclusion would contravene the Court’s decision and the CAA. By

continuing to include PM 2.5 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 avoid ing an y concern that paragraph (iii) of the two affected sections could be applied to excuse permit applicants from adequatel y addressing the monitoring requ irement for PM 2.5 . EPA also advises s tates to begin preparations to remove the PM 2.5 provisions from their state PSD regulations and SIPs. As the previously
- approved PM 2.5 SMC SIP provisions are no longer enforceable, EPA does not believe the existence of the se provisions in SIP s preclude approv al of the infrastructure SIP submissions
. EPA also advises s tates to begin preparations to remove the PM 2.5 provisions from their state PSD regulations and SIPs. As the previously
- approved PM 2.5 SMC provisions in the Mississippi SIP are no longer enforceable, EPA does not believe the existence of the seprovisions in the State ’ s implementation plan precludes approv al 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 analy sis of how the Mississippi infrastructure SIP submission meet s the requirements of the PSD e lements for the NAAQS for which it was submitted. This anal ys is 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 -**  **A pproved**  **S tructural PSD**  **P rogram**  **R equirement**  **s for Mississippi**  **State Phase II Rule**  **GHG Tailoring Rule**  **NSR PM 2.5**  **Rule PM**  **2.5 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)