Identification of Nonattainment 

Classification and Deadlines for Submission 

of State Implementation Plan (SIP) 

Provisions for the 1997 Fine Particle (PM2.5) 

National Ambient Air Quality Standard 

(NAAQS) and 2006 PM2.5 NAAQS

Response to Comments 
 

(This page intentionally left blank.)
Identification of Nonattainment Classification and 

Deadlines for Submission of State Implementation

Plan (SIP) Provisions for the 1997 Fine Particle 

(PM2.5) National Ambient Air Quality Standard 

(NAAQS) and 2006 PM2.5 NAAQS

Response to Comments

State and Local Programs Group

Air Quality Policy Division

Office of Air Quality Policy and Standards

U. S. Environmental Protection Agency

Research Triangle Park, NC 27711

May 2014
1

Identification of Nonattainment Classification and Deadlines for Submission 

of State Implementation Plan (SIP) Provisions for the 1997 Fine Particle 

(PM2.5) National Ambient Air Quality Standard (NAAQS) and 2006 PM2.5

NAAQS

Responses to Comments

A. Comment Letters Received

The Environmental Protection Agency (EPA or the Agency) received sixteen comment 

letters in response to the proposed rule titled, “Identification of Nonattainment Classification and 

Deadlines for Submission of State Implementation Plan (SIP) Provisions for the 1997 Fine 

Particle (PM2.5) National Ambient Air Quality Standard (NAAQS) and 2006 PM2.5 NAAQS” (78 

Fed. Reg. 69806, November 21, 2013). The EPA received the following comment letters:

1. Letter dated December 6, 2013 from Jeremy Nichols, Climate and Energy Program 

Director, WildEarth Guardians, to Air and Radiation Docket and Information Center. 

Re: Docket ID No. EPA-HQ-OAR-2013-0694, Proposed Rule, Identification of 

Nonattainment Classification and Deadlines for Submission of State Implementation 

Plan Provisions for the 1997 and 2006 Fine Particle National Ambient Air Quality 

Standards.

2. Letter dated December 11, 2013 from Michael G. Dowd, Director, Air Division, 

Virginia Department of Environmental Quality, to Air and Radiation Docket and 

Information Center. Re: Comments on Proposed Rule – Docket ID No. EPA-HQOAR-2013-0694.

3. Email dated December 14, 2013 from Joseph Eugene (Gene) McGill to Group AAND-R-DOCKET. Subject: Docket ID No. EPA-HQ-OAR-2013-0694; Fairbanks 

PM 2.5 nonattainment.

4. Email dated December 15, 2013 from Julie Mellum, Organizer, Take Back the Air, to 

Group A-AND-R-DOCKET. Subject: Docket ID No. EPA-HQ-OAR-2013-0694.

5. Email dated December 18, 2013 from Brenda Wilbur to Group A-AND-R-DOCKET.

Subject: Docket ID No. EPA –HQ-OAR2013-0694.

6. Letter dated December 18, 2013 from Lissa Hughes, Conservation Advocacy 

Director, Northern Alaska Environmental Center. Re: Docket ID No. EPA-HQ-OAR2013-0694.

7. Letter dated December 20, 2013 from Bart Sponseller, Bureau of Air Management –

Director, Wisconsin Department of Natural Resources, to Air and Radiation Docket 

and Information Center. Re: State of Wisconsin Comments Regarding EPA’s 

Proposed Identification of Nonattainment Classification and Deadlines for 

Submission of State Implementation Plan (SIP) Provisions for the 1997 Fine Particle 

(PM2.5) National Ambient Air Quality Standard (NAAQS) and 2006 PM2.5 

NAAQS.
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8. Email dated December 23, 2013 from Patrice Lee to Group A-AND-R-DOCKET. 

Subject: Against proposed delay in the SIP for Alaska.

9. Letter dated December 23, 2013 from Larry Hartig, Commissioner, Alaska 

Department of Environmental Conservation, to Air and Radiation Docket and 

Information Center. Re: Docket ID No. EPA-HQ-OAR-2013-0694.

10. Letter dated December 23, 2013 from E. Christopher Abruzzo, Secretary, 

Pennsylvania Department of Environmental Protection, to EPA Docket Center 

(EPA/DC). Re: Identification of Nonattainment Classification and Deadlines for 

Submission of State Implementation Plan (SIP) Provisions for the 1997 Fine Particle 

(PM2.5) National Ambient Air Quality Standards (NAAQS) and 2006 PM2.5 NAAQS: 

Proposed Rule.

11. Letter dated December 23, 2013 from Samir Sheikh, Director of Strategies and 

Incentives, San Joaquin Valley Air Pollution Control District, to Air and Radiation 

Docket and Information Center. Re: Docket No. EPA-HQ-OAR-2013-0694: 

Comments on Identification of Nonattainment Classification and Deadlines for 

Submission of State Implementation Plan (SIP) Provisions for the 1997 Fine Particle 

(PM2.5) National Ambient Air Quality Standard (NAAQS) and 2006 PM2.5 

NAAQS; Proposed Rule (78 FR 69806, November 21, 2013).

12. Letter dated December 23, 2013 from Paul Cort, EarthJustice, to Air and Radiation 

Docket and Information Center. Re: Proposed Identification of Nonattainment 

Classification and Deadlines for Submission of Fine Particle State Implementation 

Plan Provisions, 78 Fed. Reg. 69,806 (Nov. 21, 2013).

13. Letter dated December 23, 2013 from Lucinda Minton Langworthy, Counsel for the 

Utility Air Regulatory Group, Hunton & Williams LLP, to Air and Radiation Docket 

and Information Center. Re: Proposed Rule on Identification of Nonattainment 

Classification and Deadlines for Submission of State Implementation Plan (SIP) 

Provisions for the 1997 Fine Particle (PM2.5) National Ambient Air Quality Standard 

(NAAQS) and 2006 PM2.5 NAAQS.

14. Email from Joro Walker, Western Resource Advocates, to Group A-AND-RDOCKET. Subject: Docket ID No. EPA-HQ-OAR-2013-0694.

15. Email from Clean Air Fairbanks, on behalf of 145 signatories, to Group A-AND-RDOCKET. Subject: Docket ID No. EPA-HQ-OAR-2013-0694.

16. Email from Jennifer Gleason Schmidt and Terry R. Schmidt, to Group A-AND-RDOCKET. Subject: Docket ID No. EPA-HQ-OAR-2013-0694.

B. Comments

Comment 1: The Virginia Department of Environmental Quality (VA DEQ) commented that the 

rule does not clearly identify the areas to which it applies. VA DEQ believes that the rule should 

only apply to areas for which the EPA has not yet made a determination of attainment (“clean 

data determination”).

Response: The EPA identified in the proposal areas that appear to be most affected by this rule. 

These include areas for which states have not submitted a SIP and for which the EPA has not yet 

made a determination of attainment of the 1997 or 2006 PM2.5 NAAQS or for which states have 

not yet submitted a request for redesignation to attainment for the PM2.5 NAAQS. The listed 

areas are those for which the rule will likely have the most impact, but they are not the only areas 

affected by the rule. There are other areas currently designated nonattainment for the 1997 and/or 
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2006 PM2.5 NAAQS for which states likely will need to submit additional SIP elements to meet 

the applicable requirements of subpart 4 of Part D, title I, of the Clean Air Act (CAA or the Act)

and to submit SIPs addressing the nonattainment new source review (NNSR) requirements in 

subpart 4. Whether, and to what extent, any additional submissions are needed for a particular 

1997 or 2006 PM2.5 NAAQS nonattainment area will depend upon the circumstances of each 

individual nonattainment area. The EPA will continue working with states on a case-by-case 

basis to assist them in addressing subpart 4 requirements. For help with questions or further 

clarification, states should consult with their respective EPA regional offices.

Comment 2: Earthjustice and WildEarth Guardians (WEG) commented that the classification of 

PM2.5 nonattainment areas as “Moderate” occurs by operation of law upon an area’s designation

as nonattainment. The commenters allege that the classification of areas as “Moderate” does not 

require any EPA action beyond the initial designation of an area as nonattainment.

Response: The EPA agrees that subpart 4, section 188, provides that all areas designated 

nonattainment are initially classified “by operation of law” as “Moderate” nonattainment areas. 

However, as explained in the proposal, the D.C. Circuit’s ruling in Natural Resources Defense 

Council v. EPA, 706 F.3d 428 (D.C. Cir. 2013) (hereafter “NRDC”) requiring implementation of 

the PM2.5 NAAQS under subpart 4 did not occur until years after the areas were initially 

designated nonattainment under subpart 1 of Part D, title I, of the Act. As the EPA explained in 

the proposal, the NRDC holding that the EPA erred in implementing the 1997 PM2.5 NAAQS 

solely pursuant to subpart 1 should not be applied retroactively. Nonattainment area designations 

for all areas became effective many years before the 2013 NRDC decision. See 70 FR 944, 

January 5, 2005; 74 FR 58688, November 13, 2009; 76 FR 6056, February 3, 2011. Prior to the 

NRDC decision, the EPA had implemented the 1997 and 2006 PM2.5 NAAQS based on the 

general implementation provisions of subpart 1. Subpart 1 contains no nondiscretionary 

provision for classification of nonattainment areas, and the EPA did not identify any 

classifications for areas designated nonattainment. Therefore, the EPA disagrees that areas were 

classified as “Moderate” at the time of their designation. Under the interpretation that prevailed 

during years of implementation prior to the D.C. Circuit’s 2013 ruling, no classifications were 

identified or recognized, nor were subpart 4 classifications implemented. In accordance with the 

NRDC decision, and because the EPA has not previously identified nonattainment area 

classifications under subpart 4 for areas designated nonattainment for the 1997 and 2006 PM2.5

standards, the EPA identifies the classification of all areas currently designated nonattainment 

for the PM2.5 NAAQS as “Moderate” to clarify the current classification of areas.

Comment 3: Earthjustice commented that the EPA does not have authority to reset the deadlines 

for states to submit SIPs complying with subpart 4 requirements. The CAA provides that states 

with Moderate nonattainment areas are required to submit plans “18 months after the designation 

as nonattainment.” 42 USC § 7513a(a)(2)(B). Earthjustice believes states with areas designated 

nonattainment for the 1997 PM2.5 NAAQS should have submitted their Moderate area plans by 

October 5, 2006. Earthjustice asserted that a plan for the West Central Pinal area in Arizona for 

the 2006 PM2.5 standard was due September 7, 2012, and that for all other areas designated 

nonattainment for the 2006 PM2.5 standard, plans should have been submitted no later than June 

14, 2011.

Similarly, WEG commented that the EPA has no discretion to modify the deadline for 

SIP submissions under subpart 4. The CAA requires that Moderate nonattainment area SIPs be 

submitted within 18 months of the area being designated. Even if such discretion existed, and 
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WEG believes that it does not, its exercise would be constrained by the date of the NRDC

decision, so the deadline for Moderate area submissions should be no later than July 4, 2014.

Utah Physicians for a Healthy Environment and Western Resources Advocates 

commented that they oppose the EPA establishing December 31, 2014, as the deadline for states 

to submit any additional attainment-related SIP elements. Similarly, Clean Air Fairbanks, Patrice 

and Guy Lee, Joseph Eugene McGill, the Northern Alaska Environmental Center (NAEC), 

Jennifer Gleason Schmidt, Terry Schmidt, and Take Back the Air commented that the EPA 

should not “extend the deadline” for states to submit plans meeting the requirements of subpart 

4.

Response: The EPA disagrees with the commenters. In 2013, the D.C. Circuit Court of Appeals 

held that the EPA erred in applying only the provisions of subpart 1, rather than also subpart 4, to 

implement the PM2.5 NAAQS. It is the EPA’s position that the NRDC decision does not apply 

retroactively to create an obligation in the past for states to have submitted implementation plans 

under subpart 4 demonstrating attainment of the PM2.5 NAAQS. Prior to the court’s decision, the 

prevailing implementation rulemaking instructed states to submit plans solely under subpart 1. 

The D.C. Circuit Court of Appeals did not vacate this rule. Nor did the court compel the EPA to

treat the deadlines for the obligations the court announced in its decision as already having 

lapsed, and the states as if they had already failed to meet these obligations. Instead, the court 

remanded the rules at issue to the EPA for repromulgation under subpart 4. Thus, the NRDC

decision directed that the EPA act prospectively to implement the PM2.5 NAAQS under subpart 4 

through one or more national rulemakings consistent with the NRDC decision. This action is one 

such rulemaking. 

Because of the complexity of the Act’s SIP provisions and the interrelationship between 

federal and state action, the EPA believes it is inappropriate to impose retroactive effect on 

decisions in a manner that would create deadlines that have long passed. Courts have supported 

this position. For example, in Sierra Club v. Whitman, 285 F.3d 63 (D.C. Cir. 2002), the D.C. 

Circuit Court of Appeals addressed an EPA failure to make a timely determination of failure to 

attain the applicable ozone NAAQS and to reclassify the St. Louis, Missouri area. Id. at 65. 

Reclassification would have resulted in requirements for the area to submit new attainment plans. 

Id. The court ruled that the EPA was required to make the determination, but expressly rejected 

the Sierra Club’s request to consider the area as reclassified as of the date that the EPA’s 

determination should have been made. Id. at 67-68. The court refused to impose the statutory 

deadline for SIP submittals when that deadline had passed long before the court’s decision. Id. at 

67-68. The court noted that backdating the EPA’s determination would only make the situation 

worse by likely imposing large costs on the states for failing to develop SIPs years earlier even 

though the states were not on notice at the time of their obligation to do so. Id. at 68.

The historical context of the implementation of these standards deviates from the course 

contemplated by the statute. The NRDC decision has essentially changed the course of 

implementation of the standard in mid-stream. This rulemaking is not an extension of the 

deadline established by the EPA when it was implementing the PM2.5 standards according to 

subpart 1. Rather, this rulemaking makes that deadline no longer operative, since the EPA is no 

longer following only subpart 1 to implement the PM2.5 standards. Under the unique 

circumstances presented here, the EPA relies on its authority under section 301 of the CAA to 

establish a reasonable deadline, of December 31, 2014, by which states must submit SIPs 

consistent with the subpart 4 requirements. In determining a deadline, the EPA considered: the 
5

amount of time that has passed since the NRDC decision, when this rulemaking will be finalized, 

and the amount of time remaining before the 2006 PM2.5 NAAQS attainment deadline under 

subpart 4 for most areas of December 31, 2015.1 The EPA is balancing the desire to allow states 

a reasonable amount of time to develop SIP submissions that conform to subpart 4 requirements, 

while leaving enough time before the 2006 PM2.5 NAAQS attainment date so that state plans

have time to be implemented and work. In consideration of all of these circumstances, the EPA 

believes December 31, 2014 is a reasonable deadline. 

Comment 4: UARG commented that the EPA should allow states 18 months to submit any 

remaining SIP planning requirements and NNSR SIP submissions required pursuant to subpart 4 

“after the effective date of the classifications” of all PM2.5 nonattainment areas as Moderate. San 

Joaquin Valley Air Pollution Control District (APCD) commented that the EPA should allow 

states 18 months to submit any remaining SIP planning requirements and NNSR SIP 

submissions required pursuant to subpart 4. VA DEQ commented that the deadline for states to 

submit any remaining SIP planning requirements and NNSR SIP submissions required pursuant 

to subpart 4 should be “three years from final publication of a rule that clearly delineates the 

CAA mandates for SIP planning and NNSR requirements of PM2.5 [M]oderate nonattainment 

areas,” instead of December 31, 2014.

Response: The EPA disagrees with these comments. Subpart 4, section 188, provides that states 

are to submit required plans 18 months after an area is designated nonattainment. However, the 

NRDC case was not decided until years after areas were designated nonattainment under subpart 

1 of the Act. Although the statute provides states 18 months from designation to develop and 

submit plans, in light of the timing and substance of the D.C. Circuit opinion, the EPA believes 

that states should be provided a reasonable opportunity to submit any remaining SIP planning 

requirements and NNSR SIP submissions required pursuant to subpart 4. The EPA believes that 

setting the deadline for such submissions as December 31, 2014 provides a relatively brief but 

reasonable amount of time for states to ascertain whether and to what extent any additional 

submissions are needed for a particular nonattainment area, and to develop, adopt, and submit 

any such plans. The EPA balanced several considerations in determining that December 31, 2014 

is an appropriate date, as explained in the response to comment 3.

The EPA is particularly concerned that an appropriate balance would not be achieved by 

adopting a submission deadline “three years from final publication of a rule that clearly 

delineates the CAA mandates for SIP planning and NNSR requirements of PM2.5 [M]oderate 

nonattainment areas,” as suggested by VA DEQ. Because the Act provides states 18 months to 

submit required plans after an area is designated nonattainment under normal circumstances, the 

EPA believes there is no basis to provide states three years from finalization of another rule.

Additionally, the EPA notes that it has already provided information regarding subpart 4 

requirements for plans developed for PM2.5 Moderate nonattainment areas. The EPA directs 

interested parties to its longstanding general guidance, which makes recommendations to states 

for meeting the statutory requirements for SIPs for nonattainment areas. See “State 

Implementation Plans; General Preamble for the Implementation of Title I of the Clean Air Act 

Amendments of 1990” (57 FR 13498, April 16, 1992) (hereafter “1992 General Preamble”); 

 

1 The EPA designation for the West Central Pinal area in Arizona as nonattainment for the 2006 PM2.5 NAAQS 

became effective March 7, 2011. See 76 FR 6056, February 3, 2011. Therefore, the latest attainment date applicable 

to this area under subpart 4 is December 31, 2017.
6

“State Implementation Plans for Serious PM-10 Nonattainment Areas, and Attainment Date 

Waivers for PM-10 Nonattainment Areas Generally; Addendum to the General Preamble for the 

Implementation of Title I of the Clean Air Act Amendments of 1990” (59 FR 41998, August 16, 

1994) (hereafter “1994 Addendum”). This guidance includes a discussion of the subpart 1 and 

subpart 4 requirements.

Comment 5: One comment letter from Fairbanks, Alaska requested that the EPA extend the 

deadline for states like Alaska to submit SIPs to address noncompliance with the 2006 PM2.5 

NAAQS. The commenters requested that the EPA consider extending the deadline, due to what 

the commenter described as the challenging conditions that arise in the area, including cold, 

periodic windstorms, summer forest fires, winter ice fog, and the reliance on woodstoves and 

coal for heating.

Response: The EPA recognizes and appreciates that diverse regions throughout the country 

confront different challenges in their efforts to attain the PM2.5 NAAQS. Both the statute and 

EPA regulations and policy provide a range of methods for taking these differing circumstances 

into account, including, but not limited to, identifying and appropriately accounting for changes 

in air quality due to exceptional events, determining that an area should be reclassified to a 

Serious classification, and determining that an attainment deadline should be extended to allow 

for additional time to meet the standards. At this time, however, the EPA believes that initially 

all states, including the state of Alaska, should be required to meet the 2014 deadline for 

submission of a SIP addressing subpart 4 requirements for the PM2.5 standards. This will not 

preclude the state from raising the issues set forth by the commenter, nor will it preclude the 

EPA from considering them in the future. The EPA does not believe it would be appropriate to 

extend the SIP submission deadline for an individual area. Given the time that has already passed 

since area designations as a result of the shift in implementation resulting from the NRDC

decision, the EPA concludes that all areas should submit initial plans by December 31, 2014, 

addressing individual area concerns such as those raised by the commenter during the 

implementation process. Therefore, the EPA declines at this stage to extend the date for 

submission of the SIP.

Comment 6: Utah Physicians for a Healthy Environment and Western Resources Advocates 

commented that the EPA’s proposal to establish the December 31, 2014 deadline will delay the 

implementation of RACT, which is “untenable.”

Response: As explained in the proposal and in the summary of the final rule, this rulemaking 

only identifies: (1) the classification under subpart 4 of areas currently designated nonattainment 

for the 1997 and/or 2006 PM2.5 standards; (2) the deadline for states to submit any remaining SIP 

planning requirements and NNSR SIP submissions required pursuant to subpart 4; and (3) the 

EPA guidance and relevant rulemakings that are currently available regarding implementation of 

subpart 4 requirements. This rulemaking is not intended to address the timeline for the 

implementation of reasonably available control measures (RACM), including reasonably 

available control technology (RACT), under subpart 4, although the EPA may undertake a future 

rulemaking on this issue.

Comment 7: The Wisconsin Department of Environmental Protection commented in support of 

their understanding that the rulemaking would not apply to PM2.5 nonattainment areas for which 

complete redesignation applications have been submitted to the EPA. 
7

Response: The EPA in this response seeks to clarify how the EPA considers the application of 

the rulemaking for areas that have submitted complete redesignation requests. First, as a general 

matter, pursuant to section 175A(c), part D requirements, including those under subparts 1 and 4,

remain in effect until the EPA approves a redesignation request and an area is redesignated to 

attainment. However, for purposes of evaluating whether a redesignation request is approvable 

and meets the requirements of section 107(d)(3)(E)(ii) and (v), the EPA’s longstanding 

interpretation of section 107(d)(3)(E) of the CAA is that, as a threshold matter, the part D 

provisions which are “applicable” and which must be approved in order for the EPA to 

redesignate an area include only those which came due prior to a state’s submittal of a complete 

redesignation request. 78 FR 20856, 20861. See also “Procedures for Processing Requests to 

Redesignate Areas to Attainment,” Memorandum from John Calcagni, Director, Air Quality 

Management Division, September 4, 1992. Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004). 

To the extent that implementation under subpart 4 would impose additional requirements for 

areas designated nonattainment, the EPA believes that those requirements are not “applicable” 

for the purposes of CAA section 107(d)(3)(E) in any area that has submitted a complete 

redesignation request prior to the due date for these requirements, and thus the EPA is not 

required to consider subpart 4 requirements with respect to areas that have submitted a complete 

redesignation request prior to December 31, 2014. Applicable requirements of the CAA that 

come due subsequent to the area’s submittal of a complete redesignation request remain 

applicable until a redesignation is approved, but are not required as a prerequisite to 

redesignation.

Comment 8: UARG commented “that Subpart 4 requirements should not be applied retroactively 

to areas that have already attained, or that have SIPs that the EPA has determined are adequate to 

attain, the 1997 and 2006 PM2.5 NAAQS.” The commenter believes that requiring otherwise 

would impose undue planning burdens on the states.

Response: As stated previously, the EPA agrees that no requirements of subpart 4 should be 

applied retroactively. However, the EPA disagrees with the commenter’s conclusion that under 

no circumstances should any additional submissions under subpart 4 be required of any area that 

has attained the PM2.5 NAAQS or for which the EPA has approved attainment plans. The EPA 

wishes to clarify that this rulemaking does not affect any action previously taken by the EPA 

under section 110(k) of the Act on a SIP for a PM2.5 nonattainment area. However, this does not 

necessarily mean that areas for which the EPA has previously approved attainment 

demonstration or NNSR plans have met all requirements of the Act. States may need to submit 

additional SIP planning requirements and NNSR SIP elements to show that they meet all of the 

applicable requirements of subpart 4. As explained in the EPA’s response to comment 1 and 

section IV of the final rule, whether, and to what extent, any additional submissions are needed 

for a particular 1997 or 2006 PM2.5 NAAQS nonattainment area will depend upon the 

circumstances of each individual nonattainment area. States may owe additional submissions for 

any area currently designated nonattainment.

The EPA does not believe that this rule places undue planning burdens on states. Because 

the EPA is now incorporating subpart 4 along with subpart 1 in implementation of the PM2.5

NAAQS as required by the NRDC decision, states need to ensure that they have submitted all 

plan elements to the EPA that are necessary to meet the requirements of both subparts. Through 

this rulemaking, the EPA is establishing a deadline for this submission to allow states a 

reasonable period of time to take any required action to meet subpart 4.
8

Comment 9: San Joaquin Valley APCD commented to request that the EPA develop guidance 

regarding how nonattainment areas may be reclassified.

Response: As explained in the summary of the final rule, the limited purpose of this rulemaking 

is to identify: (1) the classification under subpart 4 of areas currently designated nonattainment 

for the 1997 and/or 2006 PM2.5 standards; (2) the deadline for states to submit any remaining SIP 

planning requirements and NNSR SIP submissions required pursuant to subpart 4; and (3) the 

EPA guidance and relevant rulemakings that are currently available regarding implementation of 

subpart 4 requirements. This rulemaking is not intended to address all issues that arise during

implementation, but rather answer preliminary questions to facilitate the shift in implementation 

solely under subpart 1 to also under subpart 4.

However, the EPA in this response will clarify how the Act governs area classifications 

under subpart 4. Subpart 4, section 188, provides that all areas designated nonattainment shall 

initially be classified as Moderate by operation of law. In accordance with the NRDC decision, 

and because the EPA has not previously identified nonattainment area classifications under 

subpart 4 for areas designated nonattainment for the 1997 and 2006 PM2.5 standards, the EPA 

identifies all areas as Moderate in this rulemaking to clarify the current classification of areas. At 

some future time, the EPA may reclassify as Serious any nonattainment area that the EPA 

determines cannot practicably attain the PM2.5 NAAQS by the applicable attainment date. An

area may also be reclassified as a Serious area by operation of law if the Administrator 

determines that an area has not in fact attained the PM2.5 NAAQS after the applicable attainment 

date has passed. In the 1992 General Preamble, the EPA has previously addressed the 

requirements of section 188 concerning classifications under subpart 4, including the issue of 

discretionary and mandatory reclassification from Moderate to Serious. See 57 FR 13498, at 

13537-8.

Comment 10: Earthjustice commented that this rulemaking should identify Libby, MT, San 

Joaquin Valley, CA, and the Los Angeles-South Coast Air Basin, CA, as having failed to attain 

the 1997 PM2.5 standards by the statutory attainment deadline and explain that the areas were 

reclassified by operation of law as Serious. 42 U.S.C. § 7513(b)(2). Earthjustice asserted that 

these are areas designated nonattainment for the 1997 PM2.5 standards for which the EPA has not 

made an attainment (“clean data”) determination and which have not submitted a redesignation 

request. The commenter argues that the attainment date for Moderate nonattainment areas is “the 

end of the sixth calendar year after the area’s designation as nonattainment.” 42 U.S.C. § 

7513(c)(1). According to the commenter, the attainment deadline for areas designated in 2005 as 

nonattainment for the 1997 PM2.5 NAAQS was December 31, 2010. The commenter asserts that 

the EPA was thus required to determine by June 30, 2011 whether areas had attained the relevant 

standard. 42 U.S.C. § 7513(b)(2). Because the named areas have no clean data determination and 

no submitted redesignation request for the 1997 PM2.5 standards, the commenter states that these 

areas should have been reclassified as Serious by operation of law. 42 U.S.C. § 7513(b)(2). The 

commenter argued that the EPA’s identification of the named areas as Moderate “is not only 

unlawful but also bad policy.”

Response: As explained in the proposal and in the EPA’s response to comment 3, the EPA 

believes that the D.C. Circuit Court’s 2013 holding in NRDC that the EPA erred in implementing 

the 1997 PM2.5 NAAQS solely pursuant to subpart 1 should not be applied retroactively. Prior to 

the NRDC decision, the EPA had implemented the 1997 PM2.5 NAAQS based on the provisions 

of subpart 1. States with areas designated nonattainment for the 1997 PM2.5 standards had 
9

previously been instructed by the EPA, prior to the NRDC decision, to implement and attain the 

1997 PM2.5 standards according to the general implementation provisions of subpart 1 as 

provided in the EPA’s implementation rules. The EPA therefore disagrees that Libby, MT, San 

Joaquin Valley, CA, and the Los Angeles-South Coast Air Basin, CA, were required to attain the 

1997 PM2.5 standards no later than December 31, 2010. Accordingly, the EPA disagrees that it 

had a mandatory duty to determine by June 30, 2011, whether the named areas had attained the 

1997 PM2.5 standards. As of that date, the EPA was implementing the 1997 PM2.5 standards

pursuant solely to subpart 1, and no court had ruled that the EPA or any state should implement 

the PM2.5 standards also under the provisions of subpart 4. 

Subpart 1 contains no nondiscretionary provision for classification of nonattainment 

areas. In its prior implementation of the 1997 PM2.5 standards, the EPA did not identify any 

classifications for areas under the 1997 PM2.5 standards. The EPA therefore disagrees that Libby, 

MT, San Joaquin Valley, CA, and the Los Angeles-South Coast Air Basin, CAs were reclassified 

“by operation of law” as Serious no later than June 30, 2011. Because under the EPA’s prior 

approach it did not identify nonattainment area classifications, the EPA is undertaking this 

rulemaking to identify the initial classification under subpart 4 for all areas designated 

nonattainment for the PM2.5 standards as Moderate.

At some future time, the EPA may reclassify as Serious any nonattainment area that the 

EPA determines cannot practicably attain the PM2.5 NAAQS by the applicable attainment date. 

These areas may also be reclassified as Serious by operation of law if the Administrator 

determines that the area has not in fact attained the 1997 PM2.5 NAAQS after each area’s 

applicable attainment date has passed.

Comment 11: Earthjustice further claimed that Libby, MT, San Joaquin Valley, CA, and the Los 

Angeles-South Coast Air Basin, CA, should be required to submit Moderate area and Serious 

area plans for the 1997 PM2.5 standards that satisfy the subpart 4 requirements, based on their 

contention (see Comment 10) that these areas should have been reclassified as Serious areas for 

the 1997 PM2.5 NAAQS. Earthjustice contends that these plans should have been due to the EPA 

by December 31, 2013 under 42 U.S.C. § 7513a(b)(2).

Response: As set forth in the EPA’s response to comment 10, the EPA disagrees that Libby, MT, 

San Joaquin Valley, CA, and the Los Angeles-South Coast Air Basin, CA, should be classified 

as Serious areas. Because these areas are classified as Moderate, and not Serious, the affected 

states are required at this time to submit plans for these areas that satisfy 42 U.S.C. § 7513a(a) 

and not 42 U.S.C. § 7513a(b)(1).

Comment 12: San Joaquin Valley APCD and VA DEQ commented that more specific 

information is needed from the EPA headquarters regarding the requirements of subpart 4 for 

submissions for PM2.5 Moderate areas. VA DEQ particularly requested that the EPA undertake a 

rulemaking to “delineate what attainment-related and [N]NSR requirements will be mandated by 

a [M]oderate designation.”

Response: The EPA notes that the Act does not impose a requirement on the EPA to promulgate 

an implementation rule for each NAAQS. Nat’l Ass’n of Manufacturers v. EPA, 2014 U.S. App. 

LEXIS 8726, May 9, 2014 (D.C Cir.). In the context of the unique circumstances presented here, 

the EPA seeks to respond in a timely way to the D.C. Circuit’s NRDC decision and to enable 

states similarly to respond to the court’s decision that subpart 4 applies to implementation of 

PM2.5. Thus the EPA’s purpose is to provide sufficient notice and information to enable the states 
10

to move forward in complying with the directive of the court. This rulemaking is not intended to 

address all issues that would be germane to an implementation rule, but rather answer 

preliminary questions that arise in the shift in implementation solely under subpart 1 to also 

under subpart 4. 

The EPA agrees that guidance to states is helpful to clarify requirements, and to respond 

more comprehensively to the court’s remand, but the EPA believes that this rulemaking, 

combined with the EPA’s longstanding general guidance interpreting the requirements of subpart 

4 of the CAA, provides an adequate basis for states to develop Moderate area attainment plans 

and NNSR plans. See 1992 General Preamble; 1994 Addendum. In the 1992 General Preamble, 

the EPA discussed the relationship of subpart 1 and subpart 4 SIP requirements, and pointed out 

that subpart 1 requirements were to an extent “subsumed by, or integrally related to, the more 

specific” subpart 4 requirements. 57 FR at 13538. Moreover, subsequent to the NRDC decision, 

the EPA has issued rulemakings for individual areas in which the EPA has further elaborated on 

the relationship of subpart 1 and subpart 4 requirements in the context of making determinations 

of attainment for areas that have attained the 1997 PM2.5 standards, approving requests to 

redesignate areas to attainment or approving an area’s attainment demonstration. See, e.g., 

“Approval and Promulgation of Air Quality Implementation Plans; Indiana; Redesignation of the 

Indianapolis Area to Attainment of the 1997 Annual Standard for Fine Particulate Matter” (78 

FR 20856, April 8, 2013 - proposal) (78 FR 41698, July 11, 2013 - final). 

The EPA is currently developing a proposal for a new implementation rule that would 

apply to current and future PM2.5 NAAQS. The Agency plans to propose that rule later this year. 

The proposal will address a range of implementation requirements that apply to PM2.5 

nonattainment areas under subparts 1 and 4. Until that implementation rule is finalized, the EPA 

believes that the 1992 General Preamble, 1994 Addendum, and recent rulemakings on 

Indianapolis and other areas provide helpful guidance for states in ascertaining the impact of 

subpart 4 requirements on their ongoing efforts to meet the 1997 and 2006 PM2.5 standards and 

the EPA will approve states’ submissions in consideration of the guidance offered in those 

documents.

2

In addition, the EPA regional offices can provide further clarifications and 

responses to questions that may arise in specific situations. States should consult their respective 

EPA regional offices as questions arise.

 

2 See also “Redesignation of Ohio Portion of the Parkersburg-Marietta Area to Attainment of the 1997 Annual 

Standard for Fine Particulate Matter” (78 FR 38256, June 26, 2013 – proposal) (78 FR 53275, August 29, 2013 -

final); “Redesignation of the Ohio Portion of the Wheeling Area to Attainment of the 1997 Annual Standard for Fine 

Particulate Matter” (78 FR 38247, June 26, 2013 - proposal) (78 FR 53275, August 29, 2013 - final); “Redesignation 

of the Detroit-Ann Arbor Area to Attainment of the 1997 Annual Standard and the 2006 24-Hour Standard for Fine 

Particulate Matter” (7839654, July 2, 2013 - proposal) (78 FR 53272, August 29, 2013 - final); “Redesignation of 

the Cleveland-Akron-Lorain Area for the 1997 Annual Standard and 2006 24-Hour Standard for Fine Particulate 

Matter” (78 FR 45116, July 26, 2013 - proposal) (78 FR 57270, September 18, 2013 - final); “Redesignation of the 

Ohio Portion of the Steubenville-Weirton Area to Attainment of the 1997 Annual and 2006 24-Hour Standards for 

Fine Particulate Matter” (78 FR 41752, July 11, 2013 - proposal) (78 FR 57273, September 18, 2013 - final); 

“Redesignation of Dayton-Springfield Area to Attainment of the 1997 Annual Standard for Fine Particulate Matter” 

(78 FR 45135, July 26, 2013 - proposal) (78 FR 59258, September 26, 2013 - final); “Redesignation of the CantonMassillon Area to Attainment of the 1997 Annual and 2006 24-Hour Standards for Fine Particulate Matter” (78 FR 

48087, August 7, 2013 – proposal) (78 FR 62459, October 22, 2013 - final); and “Attainment Plan for the 

Philadelphia-Wilmington, Pennsylvania-New Jersey-Delaware Nonattainment Area for the 1997 Annual Fine 

Particulate Matter Standard” (78 FR 57573, September 19, 2013 - proposal).
11

Comment 13: Clean Air Fairbanks, Joseph Eugene McGill, and NAEC commented that instead 

of allowing a “deadline extension” to states to submit SIPs for the PM2.5 NAAQS, the EPA 

should instead immediately find Alaska failed to submit a SIP for the Fairbanks nonattainment 

area.

Response: This rulemaking establishes a deadline of December 31, 2014 for states to submit 

SIPs consistent with the subpart 4 requirements, and simultaneously supersedes any other, 

previously established deadline for the submission of PM2.5 attainment or NNSR plans under 

subpart 1. In accordance with the court’s decision in NRDC, any deadline established by the EPA 

while the agency was implementing the PM2.5 standards solely under subpart 1 is being 

superseded. To the extent commenters are arguing that the EPA should determine that Alaska 

failed to submit a subpart 1 plan by the previously established December 14, 2012 deadline, the 

EPA believes that this rulemaking removes the basis to do so. In light of the NRDC decision 

there remains no outstanding requirement on Alaska to submit a plan solely addressing subpart 1. 

To the extent the commenter is arguing that the EPA should issue a finding of failure to submit 

against Alaska for a subpart 4 plan, please see the explanation provided in the EPA’s response to 

comment 14.

Comment 14: Earthjustice commented that the deadline by which states were required to have 

submitted attainment plans under subpart 4 for all PM2.5 Moderate nonattainment areas has 

passed, so the “EPA’s rulemaking here should be a finding that the states have failed to submit 

the plans required by the provisions of the Act.” The commenter believes that areas designated 

nonattainment for the 1997 PM2.5 NAAQS should have submitted their Moderate area plans by 

October 5, 2006. The commenter further alleges that a plan for the West Central Pinal area in 

Arizona for the 2006 PM2.5 standard was due September 7, 2012. For all other areas designated 

nonattainment for the 2006 PM2.5 standard, the commenter believes plans should have been 

submitted no later than June 14, 2011.

Similarly, WEG commented that the EPA is required by the CAA to make findings that 

states have failed to submit SIPs that meet the requirements of subpart 4 for all current PM2.5

nonattainment areas.

Response: The EPA disagrees with the comment. States’ obligation to submit plans to the EPA 

demonstrating attainment of the 1997 and 2006 PM2.5 NAAQS was triggered by the EPA’s 

designation of the relevant areas as nonattainment. The EPA, consistent with its prior 

interpretation of the Act, implemented the PM2.5 standards according to, and instructed states to 

follow only, the requirements of subpart 1. Subpart 1 requires states to submit SIPs to 

demonstrate attainment of the NAAQS by a date established by the EPA that is no later than 3

years after the date of designation of an area as nonattainment. 42 U.S.C. § 7502(b). 

The EPA also explained in various rulemaking and guidance documents that SIPs would 

need to meet the requirements of 42 U.S.C. § 7502(c), which governs submissions under subpart 

1. Thus, states were not instructed to submit their PM2.5 SIPs under the subpart 4 timeline, and 

they were not instructed to submit a PM2.5 SIP to meet the requirements of subpart 4. Therefore, 

the prevailing regulatory regime continuously since 2005, and until the NRDC decision in 2013, 

required submission only of subpart 1 plans, and then not until deadlines established according to 

subpart 1. As a result, the EPA has no outstanding duty to find that states have failed to make 

subpart 4 submissions that had not previously been required of states, and which were unknown 

to them at the time.
12

The commenter asserts that states should be held in default of obligations that had passed 

long before the NRDC decision that served to establish any such obligation. As explained in the 

EPA’s response to comment 3, the EPA does not believe the NRDC decision applies 

retroactively.

If the EPA were to give retroactive effect to the NRDC decision when the D.C. Circuit 

Court declined to do so, and impose past duties on states, the EPA would effectively penalize 

states that followed the EPA’s guidance and regulations to prepare SIPs solely in accordance 

with the timing and content of subpart 1. An EPA finding of failure to submit a SIP under 

subpart 4 that the commenter seeks would not give the states the opportunity to prepare or submit 

an appropriate SIP before being found in default of that obligation. 

Because the states had no notice of the timing or content of any alleged earlier subpart 4 

submissions, the EPA believes that the Administrator does not have a nondiscretionary duty to 

find failures to submit subpart 4 SIPs, and it would be inappropriate to issue such a finding.

The EPA’s position on this issue has been recently upheld in federal court. In Wildearth 

Guardians v. McCarthy, 2014 U.S. Dist. LEXIS 31267, March 11, 2014 (D. Colo.), WEG

claimed that states’ 2006 PM2.5 NAAQS SIPs should have been submitted according to the 

timeline laid out in subpart 4 of the CAA, which would have been no later than June 14, 2011. 

Because the states had made no SIP submission, WEG claimed that the EPA was required to 

make a finding that states had failed to submit subpart 4 SIPs. The Court dismissed the claim and 

agreed with the EPA’s position that “the NRDC court intended its decision to be prospective in 

effect, rather than retroactive.” Id. at *9. The Court also agreed that “the States were entitled to 

rely on the [2007 PM2.5] Implementing Rule promulgated by the EPA in scheduling the pace 

with which they would proceed in developing their PM2.5 SIPs.” Id. at *10.

Comment 15: Earthjustice commented that before this rulemaking would be finalized, “the 

deadline will have passed for submitting [S]erious area plans in those areas that failed to attain 

the 1997 PM2.5 standards,” which the commenter believes is December 31, 2013. Therefore, the

commenter believes this rulemaking should include a finding that the involved states have failed 

to submit Serious plans for these areas.

Response: As explained in the EPA’s responses to comments 10 and 11, the EPA disagrees that 

areas that failed to attain the 1997 PM2.5 standards should be classified as Serious areas. Because 

these areas are classified as Moderate, and not Serious, states are only required to submit plans 

for these areas that satisfy 42 U.S.C. § 7513a(a) and not 42 U.S.C. § 7513a(b)(1). Because states 

are not yet required to submit Serious area plans for the areas that may have failed to attain the 

1997 PM2.5 standards by a date of the commenter’s choosing, there is no basis for the EPA to 

make a finding of failure to submit.

The EPA believes that this position is supported by statute and by case law. In Sierra 

Club v. EPA, 356 F.3d 296 (D.C. Cir. 2004), the court addressed the EPA’s decision to reclassify 

Washington, D.C., from a Serious to Severe nonattainment area for the ozone NAAQS and 

declined to require the EPA to make the reclassification retroactive. Id. at 308. The 

reclassification had the effect of imposing additional obligations on Washington, D.C., for which 

the deadlines had already passed. Id. at 309. The court rejected the Sierra Club’s argument 

because it “would give the reclassification retroactive effect by holding the states in default of 

their submission obligations before the events necessary to trigger that obligation 

(reclassification) . . . occurred.” Id. at 309. Therefore, the court declined to give the 
13

reclassification retroactive effect before any deadline had been announced, and where it would 

impose a SIP submission deadline that had already passed. Id. at 309-10. See also Sierra Club v. 

Whitman, 285 F.3d 63 (D.C. Cir. 2002) (discussed in the EPA’s response to comment 3).

Comment 16: The Pennsylvania Department of Environmental Protection commented that the 

EPA should not have identified the Liberty-Clairton, PA nonattainment area as one of the areas 

most affected by this rulemaking. The state submitted a 2006 PM2.5 NAAQS attainment

demonstration for the Liberty-Clairton area to the EPA for approval on June 21, 2013.

Response: The EPA has received an attainment demonstration from Pennsylvania for the 2006 

PM2.5 standard for the Liberty-Clairton area. The EPA has not completed a final rulemaking that 

reviews the sufficiency of that submission under the CAA, and therefore the EPA does not 

comment on whether the attainment demonstration meets all subpart 4 requirements. 

Pennsylvania may need to submit additional information for the Liberty-Clairton area to meet the 

applicable requirements of subpart 4. To determine whether, and to what extent, any additional 

submissions are needed for a particular 1997 or 2006 PM2.5 NAAQS nonattainment area, 

Pennsylvania should consult with the EPA Region 3 Office.