Appendix A 

EPA’s Approach to the Review of Infrastructure SIP Submissions 

EPA is acting upon this SIP submission that address the infrastructure requirements of CAA 

sections 110(a)(1) and 110(a)(2) for NAAQS. The requirement for states to make a SIP 

submissions of these types arises out of CAA section 110(a)(1). Pursuant to section 110(a)(1), 

states must make SIP submissions “within 3 years (or such shorter period as the Administrator 

may prescribe) after the promulgation of a national primary ambient air quality standard (or any 

revision thereof),” and these SIP submissions are to provide for the “implementation, 

maintenance, and enforcement” of such NAAQS. The statute directly imposes on states the duty 

to make these SIP submissions, and the requirement to make the submissions is not conditioned 

upon EPA’s taking any action other than promulgating a new or revised NAAQS. Section 

110(a)(2) includes a list of specific elements that “[e]ach such plan” submission must address. 

EPA has historically referred to these SIP submissions made for the purpose of satisfying the 

requirements of CAA sections 110(a)(1) and 110(a)(2) as “infrastructure SIP” submissions. 

Although the term “infrastructure SIP” does not appear in the CAA, EPA uses the term to 

distinguish this particular type of SIP submission from submissions that are intended to satisfy 

other SIP requirements under the CAA, such as “nonattainment SIP” or “attainment plan SIP” 

submissions to address the nonattainment planning requirements of part D of title I of the CAA, 

“regional haze SIP” submissions required by EPA rule to address the visibility protection 

requirements of CAA section 169A, and nonattainment new source review permit program 

submissions to address the permit requirements of CAA, title I, part D. 

Section 110(a)(1) addresses the timing and general requirements for infrastructure SIP 

submissions, and section 110(a)(2) provides more details concerning the required contents of 

these submissions. The list of required elements provided in section 110(a)(2) contains a wide 

variety of disparate provisions, some of which pertain to required legal authority, some of which 

pertain to required substantive program provisions, and some of which pertain to requirements 

for both authority and substantive program provisions.1

 EPA therefore believes that while the 

timing requirement in section 110(a)(1) is unambiguous, some of the other statutory provisions 

are ambiguous. In particular, EPA believes that the list of required elements for infrastructure 

SIP submissions provided in section 110(a)(2) contains ambiguities concerning what is required 

for inclusion in an infrastructure SIP submission. 

The following examples of ambiguities illustrate the need for EPA to interpret some section 

110(a)(1) and section 110(a)(2) requirements with respect to infrastructure SIP submissions for a 

given new or revised NAAQS. One example of ambiguity is that section 110(a)(2) requires that 

“each” SIP submission must meet the list of requirements therein, while EPA has long noted that 

this literal reading of the statute is internally inconsistent and would create a conflict with the 

                                                            

1 For example: Section 110(a)(2)(E)(i) provides that states must provide assurances that they have adequate legal 

authority under state and local law to carry out the SIP; section 110(a)(2)(C) provides that states must have a SIPapproved program to address certain sources as required by part C of title I of the CAA; and section 110(a)(2)(G) 

provides that states must have legal authority to address emergencies as well as contingency plans that are triggered 

in the event of such emergencies. 
nonattainment provisions in part D of title I of the Act, which specifically address nonattainment 

SIP requirements.2 Section 110(a)(2)(I) pertains to nonattainment SIP requirements and part D 

addresses when attainment plan SIP submissions to address nonattainment area requirements are 

due. For example, section 172(b) requires EPA to establish a schedule for submission of such 

plans for certain pollutants when the Administrator promulgates the designation of an area as 

nonattainment, and section 107(d)(1)(B) allows up to two years, or in some cases three years, for 

such designations to be promulgated.3

 This ambiguity illustrates that rather than apply all the 

stated requirements of section 110(a)(2) in a strict literal sense, EPA must determine which 

provisions of section 110(a)(2) are applicable for a particular infrastructure SIP submission. 

Another example of ambiguity within sections 110(a)(1) and 110(a)(2) with respect to 

infrastructure SIPs pertains to whether states must meet all of the infrastructure SIP requirements 

in a single SIP submission, and whether EPA must act upon such SIP submission in a single 

action. Although section 110(a)(1) directs states to submit “a plan” to meet these requirements, 

EPA interprets the CAA to allow states to make multiple SIP submissions separately addressing 

infrastructure SIP elements for the same NAAQS. If states elect to make such multiple SIP 

submissions to meet the infrastructure SIP requirements, EPA can elect to act on such 

submissions either individually or in a larger combined action. Similarly, EPA interprets the 

CAA to allow it to take action on the individual parts of one larger, comprehensive infrastructure 

SIP submission for a given NAAQS without concurrent action on the entire submission. For 

example, EPA has sometimes elected to act at different times on various elements and subelements of the same infrastructure SIP submission.4

Ambiguities within sections 110(a)(1) and 110(a)(2) may also arise with respect to infrastructure 

SIP submission requirements for different NAAQS. Thus, EPA notes that not every element of 

section 110(a)(2) would be relevant, or as relevant, or relevant in the same way, for each new or 

revised NAAQS. The states’ attendant infrastructure SIP submissions for each NAAQS therefore 

could be different. For example, the monitoring requirements that a state might need to meet in 

its infrastructure SIP submission for purposes of section 110(a)(2)(B) could be very different for 

different pollutants, for example because the content and scope of a state’s infrastructure SIP 

                                                            

2 See, e.g., “Rule To Reduce Interstate Transport of Fine Particulate Matter and Ozone (Clean Air Interstate Rule); 

Revisions to Acid Rain Program; Revisions to the NOx SIP Call; Final Rule,” 70 FR 25162, at 25163 – 65 (May 12, 

2005) (explaining relationship between timing requirement of section 110(a)(2)(D) versus section 110(a)(2)(I)).

3 EPA notes that this ambiguity within section 110(a)(2) is heightened by the fact that various subparts of part D set 

specific dates for submission of certain types of SIP submissions in designated nonattainment areas for various 

pollutants. Note, e.g., that section 182(a)(1) provides specific dates for submission of emissions inventories for the 

ozone NAAQS. Some of these specific dates are necessarily later than three years after promulgation of the new or 

revised NAAQS.

4 On December 14, 2007, the State of Tennessee, through the Tennessee Department of Environment and 

Conservation, made a SIP revision to EPA demonstrating that the State meets the requirements of sections 110(a)(1) 

and (2). EPA proposed action for infrastructure SIP elements (C) and (J) on January 23, 2012 (77 FR 3213) and took 

final action on March 14, 2012 (77 FR 14976). On April 16, 2012 (77 FR 22533) and July 23, 2012 (77 FR 42997), 

EPA took separate proposed and final actions on all other section 110(a)(2) infrastructure SIP elements of 

Tennessee’s December 14, 2007 submittal.
submission to meet this element might be very different for an entirely new NAAQS than for a 

minor revision to an existing NAAQS.5 

EPA notes that interpretation of section 110(a)(2) is also necessary when EPA reviews other 

types of SIP submissions required under the CAA. Therefore, as with infrastructure SIP 

submissions, EPA also has to identify and interpret the relevant elements of section 110(a)(2) 

that logically apply to these other types of SIP submissions. For example, section 172(c)(7) 

requires that attainment plan SIP submissions required by part D have to meet the “applicable 

requirements” of section 110(a)(2). Thus, for example, attainment plan SIP submissions must 

meet the requirements of section 110(a)(2)(A) regarding enforceable emission limits and control 

measures and section 110(a)(2)(E)(i) regarding air agency resources and authority. By contrast, it 

is clear that attainment plan SIP submissions required by part D would not need to meet the 

portion of section 110(a)(2)(C) that pertains to the PSD program required in part C of title I of 

the CAA, because PSD does not apply to a pollutant for which an area is designated 

nonattainment and thus subject to part D planning requirements. As this example illustrates, each 

type of SIP submission may implicate some elements of section 110(a)(2) but not others. 

Given the potential for ambiguity in some of the statutory language of section 110(a)(1) and 

section 110(a)(2), EPA believes that it is appropriate to interpret the ambiguous portions of 

section 110(a)(1) and section 110(a)(2) in the context of acting on a particular SIP submission. In 

other words, EPA assumes that Congress could not have intended that each and every SIP 

submission, regardless of the NAAQS in question or the history of SIP development for the 

relevant pollutant, would meet each of the requirements, or meet each of them in the same way. 

Therefore, EPA has adopted an approach under which it reviews infrastructure SIP submissions 

against the list of elements in section 110(a)(2), but only to the extent each element applies for 

that particular NAAQS. 

Historically, EPA has elected to use guidance documents to make recommendations to states for 

infrastructure SIPs, in some cases conveying needed interpretations on newly arising issues and 

in some cases conveying interpretations that have already been developed and applied to 

individual SIP submissions for particular elements.6

 EPA most recently issued guidance for 

infrastructure SIPs on September 13, 2013 (2013 Guidance).7 EPA developed this document to 

provide states with up-to-date guidance for infrastructure SIPs for any new or revised NAAQS. 

Within this guidance, EPA describes the duty of states to make infrastructure SIP submissions to 

meet basic structural SIP requirements within three years of promulgation of a new or revised 

NAAQS. EPA also made recommendations about many specific subsections of section 110(a)(2) 

                                                            

5 For example, implementation of the 1997 PM2.5 NAAQS required the deployment of a system of new monitors to 

measure ambient levels of that new indicator species for the new NAAQS. 6 EPA notes, however, that nothing in the CAA requires EPA to provide guidance or to promulgate regulations for 

infrastructure SIP submissions. The CAA directly applies to states and requires the submission of infrastructure SIP 

submissions, regardless of whether or not EPA provides guidance or regulations pertaining to such submissions. 

EPA elects to issue such guidance in order to assist states, as appropriate. 7 “Guidance on Infrastructure State Implementation Plan (SIP) Elements under Clean Air Act Sections 110(a)(1) 

and 110(a)(2),” Memorandum from Stephen D. Page, September 13, 2013. 
that are relevant in the context of infrastructure SIP submissions.8

 The guidance also discusses 

the substantively important issues that are germane to certain subsections of section 110(a)(2). 

Significantly, EPA interprets sections 110(a)(1) and 110(a)(2) such that infrastructure SIP 

submissions need to address certain issues and need not address others. Accordingly, EPA 

reviews each infrastructure SIP submission for compliance with the applicable statutory 

provisions of section 110(a)(2), as appropriate. 

As an example, section 110(a)(2)(E)(ii) is a required element of section 110(a)(2) for 

infrastructure SIP submissions. Under this element, a state must meet the substantive 

requirements of section 128, which pertain to state boards that approve permits or enforcement 

orders and heads of executive agencies with similar powers. Thus, EPA reviews infrastructure 

SIP submissions to ensure that the state’s SIP appropriately addresses the requirements of section 

110(a)(2)(E)(ii) and section 128. The 2013 Guidance explains EPA’s interpretation that there 

may be a variety of ways by which states can appropriately address these substantive statutory 

requirements, depending on the structure of an individual state’s permitting or enforcement 

program (e.g., whether permits and enforcement orders are approved by a multi-member board 

or by a head of an executive agency). However they are addressed by the state, the substantive 

requirements of section 128 are necessarily included in EPA’s evaluation of infrastructure SIP 

submissions because section 110(a)(2)(E)(ii) explicitly requires that the state satisfy the 

provisions of section 128. 

As another example, EPA’s review of infrastructure SIP submissions with respect to the PSD 

program requirements in sections 110(a)(2)(C), (D)(i)(II), and (J) focuses upon the structural 

PSD program requirements contained in part C and EPA’s PSD regulations. Structural PSD 

program requirements include provisions necessary for the PSD program to address all regulated 

sources and NSR pollutants, including GHGs. By contrast, structural PSD program requirements 

do not include provisions that are not required under EPA’s regulations at 40 CFR 51.166 but are 

merely available as an option for the state, such as the option to provide grandfathering of 

complete permit applications with respect to the 2012 PM2.5 NAAQS. Accordingly, the latter 

optional provisions are types of provisions EPA considers irrelevant in the context of an 

infrastructure SIP action. 

For other section 110(a)(2) elements, however, EPA’s review of a state’s infrastructure SIP 

submission focuses on assuring that the state’s SIP meets basic structural requirements. For 

example, section 110(a)(2)(C) includes, inter alia, the requirement that states have a program to 

regulate minor new sources. Thus, EPA evaluates whether the state has an EPA-approved minor 

new source review program and whether the program addresses the pollutants relevant to that 

NAAQS. In the context of acting on an infrastructure SIP submission, however, EPA does not 

                                                            

8 EPA’s September 13, 2013, guidance did not make recommendations with respect to infrastructure SIP 

submissions to address section 110(a)(2)(D)(i)(I). EPA issued the guidance shortly after the U.S. Supreme Court 

agreed to review the D.C. Circuit decision in EME Homer City, 696 F.3d7 (D.C. Cir. 2012) which had interpreted 

the requirements of section 110(a)(2)(D)(i)(I). In light of the uncertainty created by ongoing litigation, EPA elected 

not to provide additional guidance on the requirements of section 110(a)(2)(D)(i)(I) at that time. As the guidance is 

neither binding nor required by statute, whether EPA elects to provide guidance on a particular section has no 

impact on a state’s CAA obligations. 
think it is necessary to conduct a review of each and every provision of a state’s existing minor 

source program (i.e., already in the existing SIP) for compliance with the requirements of the 

CAA and EPA’s regulations that pertain to such programs. 

With respect to certain other issues, EPA does not believe that an action on a state’s 

infrastructure SIP submission is necessarily the appropriate type of action in which to address 

possible deficiencies in a state’s existing SIP. These issues include: (i) existing provisions related 

to excess emissions from sources during periods of startup, shutdown, or malfunction that may 

be contrary to the CAA and EPA’s policies addressing such excess emissions (“SSM”); (ii) 

existing provisions related to “director’s variance” or “director’s discretion” that may be contrary 

to the CAA because they purport to allow revisions to SIP-approved emissions limits while 

limiting public process or not requiring further approval by EPA; and (iii) existing provisions for 

PSD programs that may be inconsistent with current requirements of EPA’s “Final NSR 

Improvement Rule,” 67 FR 80186 (December 31, 2002), as amended by 72 FR 32526 (June 13, 

2007) (“NSR Reform”). Thus, EPA believes it may approve an infrastructure SIP submission 

without scrutinizing the totality of the existing SIP for such potentially deficient provisions and 

may approve the submission even if it is aware of such existing provisions.9 It is important to 

note that EPA’s approval of a state’s infrastructure SIP submission should not be construed as 

explicit or implicit re-approval of any existing potentially deficient provisions that relate to the 

three specific issues just described. 

EPA’s approach to review of infrastructure SIP submissions is to identify the CAA requirements 

that are logically applicable to that submission. EPA believes that this approach to the review of 

a particular infrastructure SIP submission is appropriate, because it would not be reasonable to 

read the general requirements of section 110(a)(1) and the list of elements in 110(a)(2) as 

requiring review of each and every provision of a state’s existing SIP against all requirements in 

the CAA and EPA regulations merely for purposes of assuring that the state in question has the 

basic structural elements for a functioning SIP for a new or revised NAAQS. Because SIPs have 

grown by accretion over the decades as statutory and regulatory requirements under the CAA 

have evolved, they may include some outmoded provisions and historical artifacts. These 

provisions, while not fully up to date, nevertheless may not pose a significant problem for the 

purposes of “implementation, maintenance, and enforcement” of a new or revised NAAQS when 

EPA evaluates adequacy of the infrastructure SIP submission. EPA believes that a better 

approach is for states and EPA to focus attention on those elements of section 110(a)(2) of the 

CAA most likely to warrant a specific SIP revision due to the promulgation of a new or revised 

NAAQS or other factors. 

For example, EPA’s 2013 Guidance gives simpler recommendations with respect to carbon 

monoxide than other NAAQS pollutants to meet the visibility requirements of section 

110(a)(2)(D)(i)(II), because carbon monoxide does not affect visibility. As a result, an 

                                                            

9By contrast, EPA notes that if a state were to include a new provision in an infrastructure SIP submission that 

contained a legal deficiency, such as a new exemption for excess emissions during SSM events, then EPA would 

need to evaluate that provision for compliance against the rubric of applicable CAA requirements in the context of 

the action on the infrastructure SIP. 
infrastructure SIP submission for any future new or revised NAAQS for carbon monoxide need 

only state this fact in order to address the visibility prong of section 110(a)(2)(D)(i)(II). 

Finally, EPA believes that its approach with respect to infrastructure SIP requirements is based 

on a reasonable reading of sections 110(a)(1) and 110(a)(2) because the CAA provides other 

avenues and mechanisms to address specific substantive deficiencies in existing SIPs. These 

other statutory tools allow EPA to take appropriately tailored action, depending upon the nature 

and severity of the alleged SIP deficiency. Section 110(k)(5) authorizes EPA to issue a “SIP call” 

whenever the Agency determines that a state’s SIP is substantially inadequate to attain or 

maintain the NAAQS, to mitigate interstate transport, or to otherwise comply with the CAA.10

Section 110(k)(6) authorizes EPA to correct errors in past actions, such as past approvals of SIP 

submissions.11 Significantly, EPA’s determination that an action on a state’s infrastructure SIP 

submission is not the appropriate time and place to address all potential existing SIP deficiencies 

does not preclude EPA’s subsequent reliance on provisions in section 110(a)(2) as part of the 

basis for action to correct those deficiencies at a later time. For example, although it may not be 

appropriate to require a state to eliminate all existing inappropriate director’s discretion 

provisions in the course of acting on an infrastructure SIP submission, EPA believes that section 

110(a)(2)(A) may be among the statutory bases that EPA relies upon in the course of addressing 

such deficiency in a subsequent action.12 

                                                            

10 For example, EPA issued a SIP call to Utah to address specific existing SIP deficiencies related to the treatment 

of excess emissions during SSM events. See “Finding of Substantial Inadequacy of Implementation Plan; Call for 

Utah State Implementation Plan Revisions,” 74 FR 21639 (April 18, 2011). 

11 EPA has used this authority to correct errors in past actions on SIP submissions related to PSD programs. See 

“Limitation of Approval of Prevention of Significant Deterioration Provisions Concerning Greenhouse Gas 

Emitting-Sources in State Implementation Plans; Final Rule,” 75 FR 82536 (December 30, 2010). EPA has 

previously used its authority under CAA section 110(k)(6) to remove numerous other SIP provisions that the 

Agency determined it had approved in error. See, e.g., 61 FR 38664 (July 25, 1996) and 62 FR 34641 (June 27, 

1997) (corrections to American Samoa, Arizona, California, Hawaii, and Nevada SIPs); 69 FR 67062 (November 

16, 2004) (corrections to California SIP); and 74 FR 57051 (November 3, 2009) (corrections to Arizona and Nevada 

SIPs).

12 See, e.g., EPA’s disapproval of a SIP submission from Colorado on the grounds that it would have included a 

director’s discretion provision inconsistent with CAA requirements, including section 110(a)(2)(A). See, e.g., 75 FR 

42342 at 42344 (July 21, 2010) (proposed disapproval of director’s discretion provisions); 76 FR 4540 (Jan. 26, 

2011) (final disapproval of such provisions).