[Federal Register Volume 78, Number 182 (Thursday, September 19, 2013)]
[Proposed Rules]
[Pages 57573-57585]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-22829]


-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R03-OAR-2010-0141; FRL-9901-16-Region 3]


Approval and Promulgation of Air Quality Implementation Plans; 
Delaware; Attainment Plan for the Philadelphia-Wilmington, 
Pennsylvania-New Jersey-Delaware Nonattainment Area for the 1997 Annual 
Fine Particulate Matter Standard

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed Rule; Supplemental.

-----------------------------------------------------------------------

SUMMARY: EPA is issuing a supplement to its proposed approval of 
Delaware's state implementation plan (SIP) published in the Federal 
Register on November 19, 2012. The SIP revision demonstrates Delaware's 
attainment of the 1997 annual fine particulate matter 
(PM2.5) national ambient air quality standard (NAAQS) for 
the Philadelphia-Wilmington, Pennsylvania-New Jersey-Delaware (PA-NJ-
DE) PM2.5 nonattainment area. This supplemental proposal 
addresses the potential effects of a January 4, 2013 decision of the 
United States Court of Appeals for the District of Columbia Circuit (DC 
Circuit Court) remanding to EPA two final rules implementing the 1997 
PM2.5 NAAQS on EPA's proposed action. In addition, EPA is 
revising its proposed approval of Delaware's attainment plan for the 
1997 annual PM2.5 NAAQS to not rely upon regulations which 
were part of the plan submitted by Delaware because they are not 
necessary to demonstrate attainment. Finally, EPA is proposing to 
approve the 2009 and 2012 motor

[[Page 57574]]

vehicle emissions budgets (MVEBs) used for transportation conformity 
purposes for New Castle County in Delaware. EPA is seeking comment only 
on the issues raised in this supplemental proposal and is not reopening 
for comment other issues addressed in its prior proposal.

DATES: Written comments must be received on or before October 21, 2013.

ADDRESSES: Submit your comments, identified by Docket ID Number EPA-
R03-OAR-2010-0141 by one of the following methods:
    A. www.regulations.gov. Follow the on-line instructions for 
submitting comments.
    B. Email: [email protected].
    C. Mail: EPA-R03-OAR-2010-0141, Cristina Fernandez, Associate 
Director, Office of Air Planning Program, Mailcode 3AP30, U.S. 
Environmental Protection Agency, Region III, 1650 Arch Street, 
Philadelphia, Pennsylvania 19103.
    D. Hand Delivery: At the previously-listed EPA Region III address. 
Such deliveries are only accepted during the Docket's normal hours of 
operation, and special arrangements should be made for deliveries of 
boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-R03-OAR-
2010-0141. EPA's policy is that all comments received will be included 
in the public docket without change, and may be made available online 
at www.regulations.gov, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through www.regulations.gov or email. The 
www.regulations.gov Web site is an ``anonymous access'' system, which 
means EPA will not know your identity or contact information unless you 
provide it in the body of your comment. If you send an email comment 
directly to EPA without going through www.regulations.gov, your email 
address will be automatically captured and included as part of the 
comment that is placed in the public docket and made available on the 
Internet. If you submit an electronic comment, EPA recommends that you 
include your name and other contact information in the body of your 
comment and with any disk or CD-ROM you submit. If EPA cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, EPA may not be able to consider your comment. Electronic 
files should avoid the use of special characters, any form of 
encryption, and be free of any defects or viruses.
    Docket: All documents in the electronic docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, i.e., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available either electronically in www.regulations.gov or 
in hard copy during normal business hours at the Air Protection 
Division, U.S. Environmental Protection Agency, Region III, 1650 Arch 
Street, Philadelphia, Pennsylvania 19103. Copies of the State submittal 
are available at the Delaware Department of Natural Resources and 
Environmental Control, 89 Kings Highway, P.O. Box 1401, Dover, Delaware 
19903.

FOR FURTHER INFORMATION CONTACT: Rose Quinto, (215) 814-2182, or by 
email at [email protected].

SUPPLEMENTARY INFORMATION:

I. Background

    EPA previously proposed to approve a SIP revision submitted by the 
State of Delaware to meet the attainment plan requirements for the 1997 
annual PM2.5 NAAQS for the Philadelphia-Wilmington, 
Pennsylvania-New Jersey-Delaware (PA-NJ-DE) nonattainment area (the 
``Philadelphia Area'') on November 19, 2012 (77 FR 69399). Delaware 
initially submitted the attainment plan on April 3, 2008, and amended 
it on April 25, 2012, in order to address issues related to MVEBs. This 
SIP submission did not include the New Source Review (NSR) program 
requirements for the 1997 PM2.5 NAAQS, which the State and 
EPA have addressed separately.\1\
---------------------------------------------------------------------------

    \1\ EPA approved Delaware's SIP submission for the NSR program 
requirements for the 1997 PM2.5 NAAQS on October 2, 2012 
(77 FR 60053).
---------------------------------------------------------------------------

    EPA's November 19, 2012 notice of proposed rulemaking (NPR), 
proposed to approve Delaware's SIP submission as meeting all relevant 
statutory and regulatory requirements for attainment plans for the 1997 
annual PM2.5 NAAQS.\2\ EPA stated in the NPR that it had 
``determined that Delaware's attainment demonstration meets the 
applicable requirements of the Clean Air Act (CAA), as described in the 
PM2.5 Implementation Rule published on April 25, 2007.'' 
Thus, Delaware submitted the attainment plan, and EPA proposed action 
on that submission, premised upon the belief that attainment plan 
requirements for the 1997 annual PM2.5 NAAQS should be 
designed to meet, and measured against, the statutory requirements of 
CAA as interpreted in EPA's existing implementation rules.\3\
---------------------------------------------------------------------------

    \2\ See 77 FR 69399. EPA notes that the November 19, 2012 NPR 
also addressed the MVEBs for transportation conformity purposes for 
New Castle County, Delaware. EPA is supplementing its proposed 
action on the MVEBs and is taking additional comment on that portion 
of the prior proposed action based on EPA's further evaluation of 
Delaware's proposed MVEBs even though MVEBs are unaffected by the 
intervening court decision in NRDC v. EPA.
    \3\ EPA notes that although the CAA imposes no statutory duty 
upon EPA to issue implementation rules or guidance for the 
PM2.5 NAAQS, historically, EPA has elected to issue 
implementation rules or guidance in order to assist states with the 
development of SIPs so that both states and EPA can better meet 
their respective statutory obligations.
---------------------------------------------------------------------------

    Subsequent to Delaware's submission of the attainment plan and 
EPA's proposed action upon it, however, the D.C. Circuit Court issued a 
decision with potential impacts on EPA's proposed action. On January 4, 
2013, in NRDC v. EPA, the D.C. Circuit Court remanded to EPA both the 
``Final Clean Air Fine Particle Implementation Rule'' (the ``2007 
PM2.5 Implementation Rule'') \4\ and the ``Implementation of 
the New Source Review (NSR) Program for Particulate Matter Less than 
2.5 Micrometers (PM2.5)'' final rule (the ``2008 
PM2.5 NSR/Prevention of Significant Deterioration (PSD) 
Implementation Rule'').\5\ The D.C. Circuit Court found that EPA erred 
in both rules in implementing the 1997 PM2.5 NAAQS solely 
pursuant to the general implementation provisions of subpart 1 of Part 
D of Title I of the CAA (subpart 1), rather than also pursuant to the 
implementation provisions specific to particulate matter in subpart 4 
of Part D of Title I (subpart 4).\6\ As a result, the D.C. Circuit 
Court remanded both rules and instructed EPA ``to repromulgate these 
rules pursuant to subpart 4 consistent with this opinion.'' 
Significantly, the D.C. Circuit Court's decision remanded the rules to 
EPA and did not vacate them. In a future rulemaking action, EPA intends 
to respond to the D.C. Circuit Court's remand and to promulgate new 
implementation regulations for the PM2.5 NAAQS in accordance 
with the requirements of subpart 4. In the

[[Page 57575]]

interim, one limited purpose of this supplemental rulemaking action on 
the Delaware attainment plan for the Philadelphia Area is to reevaluate 
EPA's proposed approval in light of the potential effects of the D.C. 
Circuit Court's decision on implementation of the 1997 PM2.5 
NAAQS.
---------------------------------------------------------------------------

    \4\ See 72 FR 20586, April 25, 2007.
    \5\ See 73 FR 28321, May 16, 2008.
    \6\ The D.C. District Court's opinion in NRDC v. EPA did not 
expressly consider that implementation under subpart 4 requirements 
also includes continued application of relevant subpart 1 
requirements, to the extent that subpart 4 does not override subpart 
1.
---------------------------------------------------------------------------

    In addition, EPA notes that in a separate rulemaking action, 
published on February 22, 2013, EPA identified deficiencies associated 
with several regulations within the approved Delaware SIP including a 
specific provision within 7-1100-1142 Del. Code Regs Sec.  2 
(Regulation 1142, Section 2.0, Control of Nitrogen Oxide (NOx) 
Emissions from Industrial Boilers and Process Heaters at Petroleum 
Refineries). See 78 FR 12460, February 22, 2013. In that proposed 
rulemaking action, EPA identified specific Delaware regulations in 
which state officials are provided unbounded discretion to set 
alternative emission limits during periods of start-up and shutdown of 
equipment through a permitting process that does not entail subsequent 
approval of the alternative emission limits through a SIP submission. 
EPA has proposed to find that this process constitutes an impermissible 
director's discretion provision with the potential to allow 
impermissible discretionary exemptions from SIP emission limits. See 78 
FR at 12495-12496. Today's rulemaking action providing supplemental 
analysis and a revised proposal on Delaware's 1997 annual 
PM2.5 attainment plan is separate from the February 22, 2013 
action. EPA's action in this supplemental proposal does not reopen the 
public comment period associated with the separate February 22, 2013 
action; nor does today's rulemaking action purport to revise or amend 
that separate proposed action. EPA will be taking a separate final 
action on the February 22, 2013 proposed rulemaking action. Today's 
rulemaking action proposes to revise EPA's original proposal in the 
November 19, 2012 NPR to propose approval of Delaware's 1997 
PM2.5 attainment plan as meeting the requirements for 
attainment plans for the 1997 PM2.5 NAAQS, without reliance 
on certain measures identified in the attainment plan: (1) Regulation 
1142 Section 2.0 for NOX emissions at petroleum refineries; 
(2) certain control measures for volatile organic compound (VOC) 
emissions; and (3) the Clean Air Interstate Rule (CAIR). These measures 
are not necessary for the purposes of Reasonably Available Control 
Measures (RACM), Reasonably Available Control Technology (RACT), 
section 189(e), or the attainment demonstration. EPA is not relying on 
Regulation 1142 Section 2.0, the VOC control measures, and CAIR as 
these measures are not necessary for expeditious attainment of the 1997 
PM2.5 NAAQS in the Philadelphia Area for the reasons 
described in detail in this rulemaking action.\7\
---------------------------------------------------------------------------

    \7\ As discussed in more detail later in this notice, EPA is 
also proposing herein to approve the 2009 and 2012 MVEBs for New 
Castle County in Delaware.
---------------------------------------------------------------------------

    Like many of the areas which EPA initially designated nonattainment 
for the 1997 PM2.5 NAAQS, the Philadelphia Area has already 
attained these NAAQS. EPA has issued both a clean data determination 
and a determination of attainment for the Philadelphia Area.\8\ 
However, because Delaware has already submitted the attainment plan for 
the Philadelphia Area, and has not withdrawn it, EPA needs to evaluate 
the SIP submission for compliance with the CAA. In the context of 
taking action under section 110(k) to approve or disapprove a 
previously submitted attainment plan for the 1997 PM2.5 
NAAQS for an area that has attained the NAAQS, EPA believes that it 
would be helpful after the D.C. Circuit Court's decision to consider 
such pending attainment plans in light of the provisions of subpart 4.
---------------------------------------------------------------------------

    \8\ EPA issued both a determination of attainment and a clean 
data determination for the Philadelphia Area on May 16, 2012 (77 FR 
28782).
---------------------------------------------------------------------------

    Accordingly, EPA has considered possible approaches to evaluating 
pending attainment plans for the 1997 PM2.5 NAAQS that 
states have already developed and submitted to EPA in reliance on the 
remanded 2007 PM2.5 Implementation Rule. One potential 
approach would be for EPA to request that the state in question simply 
withdraw its pending SIP submission in toto, engage in a new state 
rulemaking process to revise and restructure the contents of the 
submission in order to address subpart 4 requirements explicitly, and 
then to resubmit the revised submission to EPA. Such an approach could, 
however, require substantial investment of additional rulemaking 
resources by both the state and EPA and could inject substantial 
unwarranted delay into the process. Although such an approach might be 
appropriate in the case of some nonattainment areas, e.g., those with 
continuing nonattainment problems for the 1997 PM2.5 NAAQS, 
EPA questions whether this approach would be constructive in all areas. 
In particular, EPA questions the necessity for such a resource and time 
intensive approach for areas that are already factually attaining the 
1997 PM2.5 NAAQS through the attainment plan already adopted 
and submitted by the state.
    An alternative approach would be for EPA to proceed to evaluate the 
State's existing attainment plan submission for the 1997 
PM2.5 NAAQS in order to determine whether it would meet not 
only the applicable requirements of subpart 1, but also meet the 
applicable requirements of subpart 4. This approach would be consistent 
with the D.C. Circuit Court's decision that EPA must implement the 
PM2.5 NAAQS consistent with the requirements of subpart 4. 
As set forth in this rulemaking action, although Delaware's plan was 
originally submitted to address subpart requirements in light of the 
important fact that the Area has attained the 1997 PM2.5 
NAAQS, EPA believes that the submission adequately addresses the 
requirements of both subparts 1 and 4. In these circumstances, where 
the existing attainment plan submission is adequate, Delaware and EPA 
can preserve limited resources for efforts that may be needed to 
address any ongoing nonattainment problems under the 2006 
PM2.5 NAAQS and the 2012 PM2.5 NAAQS.
    EPA intends to provide a comprehensive response to the DC Circuit 
Court's remand in NRDC v. EPA in a future rulemaking action. In the 
interim, EPA will proceed to review attainment plans that have already 
been submitted but are not yet approved where appropriate. In this 
supplemental notice, EPA examines the substance of Delaware's SIP 
submission with regard to consistency with subpart 4 as well as subpart 
1. With respect to the relevant substantive requirements for attainment 
plans, EPA notes that subpart 1 contains general air quality planning 
requirements for areas designated nonattainment. By contrast, subpart 4 
contains air quality planning requirements specifically applicable to 
PM10 nonattainment areas.\9\ Under the D.C. Circuit Court's 
January 4, 2013 decision in NRDC v. EPA, these same statutory 
requirements also apply for PM2.5 nonattainment areas. EPA 
has longstanding general guidance documents that interpret the 1990 
amendments to the CAA, commonly known as the ``General Preamble'' and 
the ``Addendum,'' that make recommendations to states for meeting the 
statutory requirements for SIPs for nonattainment areas including those 
of

[[Page 57576]]

subpart 4.\10\ In the General Preamble, 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 PM10 requirements.'' \11\
---------------------------------------------------------------------------

    \9\ PM10 refers to particulates nominally 10 
micrometers in diameter or smaller. CAA section 302(t).
    \10\ 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, General Preamble). EPA 
notes that it has issued additional guidance for attainment plans 
for PM10 in particular, including extra requirements for 
areas classified as ``serious'' nonattainment areas under subpart 4. 
See ``State Implementation Plans for Serious PM10 
Nonattainment Areas, and Attainment Date Waivers for PM10 
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, Addendum).
    \11\ See 57 FR 13538.
---------------------------------------------------------------------------

    The requirements of subpart 1 for attainment plans include, among 
other things: (1) Section 172(c)(1) (RACM, RACT, and attainment 
demonstrations); (2) section 172(c)(2) (reasonable further progress 
(``RFP'')); (3) section 172(c)(3) (emissions inventories); (4) section 
172(c)(5) (NSR permit program); and (5) section 172(c)(9) (contingency 
measures). The subpart 4 requirements for attainment plans are 
generally comparable, but also impose distinct requirements for 
nonattainment areas based upon the area's classification as either 
``moderate'' or ``serious'' and set some specific timing requirements, 
such as for imposition of control measures. In general, the specific 
requirements for attainment plans required initially of all areas under 
subpart 4 include: (1) Section 189(a)(1)(A) (NSR permit program); (2) 
section 189(a)(1)(B), (attainment demonstration); (3) section 
189(a)(1)(C) (RACM and RACT); (4) section 189(c) (RFP and quantitative 
milestones); and (5) section 189(e) (precursor requirements for major 
stationary sources). Subpart 4 also includes additional statutory SIP 
planning requirements in the event that EPA reclassifies a moderate 
nonattainment area to a serious nonattainment area and in the event the 
area needs additional extensions of time to attain the NAAQS. The 
General Preamble and Addendum provide useful additional guidance on the 
specific subpart 4 statutory requirements.
    For the purposes of evaluating the Delaware attainment plan for the 
Philadelphia Area for the 1997 annual PM2.5 NAAQS, EPA 
believes that the State's submission satisfies the relevant provisions 
of subpart 4. The analysis supporting this conclusion is described in 
more detail in this rulemaking action. After addressing the 
classification of the Area under subpart 4, EPA discusses the pending 
SIP submission from the perspective of subpart 4 requirements, 
following the same topic order as the November 19, 2012 NPR: (1) 
Pollutants addressed; (2) emissions inventory requirements; (3) 
modeling; (4) RACM and RACT; (5) RFP; (6) contingency measures; and (7) 
attainment date. For each of these topics, EPA considers the potential 
impact of the D.C. Circuit Court's decision in NRDC v. EPA on EPA's 
proposed approval of the Delaware attainment plan for the 1997 annual 
PM2.5 NAAQS for the Philadelphia Area.

II. EPA's Analysis

A. Classification

    A preliminary step in evaluating the State's attainment plan 
submission for compliance with subpart 4 requirements is ascertaining 
the correct classification of the Philadelphia Area as either a 
``moderate'' or a ``serious'' nonattainment area. EPA's designations 
for the 1997 annual PM2.5 NAAQS did not include any 
classifications for nonattainment areas, but this Area would 
automatically have been classified as a ``moderate'' nonattainment 
area.\12\ Under section 188, the CAA provides that all areas designated 
nonattainment under subpart 4 should initially be classified ``by 
operation of law'' as moderate nonattainment areas, and that they 
remain classified as moderate nonattainment areas unless and until EPA 
later reclassifies the area as a serious nonattainment area.\13\
---------------------------------------------------------------------------

    \12\ EPA notes that in 2005, it was proceeding under the 
assumption that it was appropriate to implement the 1997 
PM2.5 NAAQS under subpart 1 and accordingly did not 
classify areas at the time of the designations.
    \13\ EPA has already addressed the requirements of section 188 
concerning classifications under subpart 4, including the issue of 
discretionary and mandatory reclassification from moderate to 
serious, in the General Preamble. See 57 FR 13498, at 13537-8. There 
is no basis to conclude that the Philadelphia Area should be 
reclassified from moderate to serious. Under section 188(b), EPA has 
authority to reclassify a moderate area to serious before the 
attainment date if the Administrator determines that the area cannot 
attain the NAAQS by the applicable attainment date under section 
188(c)(1) for moderate areas, i.e., by the end of the sixth calendar 
year after designation. Under section 188(b)(2), EPA has a duty to 
reclassify such a moderate area to serious if the area fails to 
attain by the applicable attainment date. Because the Philadelphia 
Area began attaining the 1997 annual PM2.5 NAAQS in 2010, 
and continued to attain in the sixth calendar year following the 
designation of the area effective in April of 2005, there would 
therefore be no basis for reclassification of the area to serious 
and thus no need to require the state to address the statutory 
requirements for an attainment plan for a serious nonattainment area 
under subpart 4.
---------------------------------------------------------------------------

    Thus, for purposes of evaluating the attainment plan submitted by 
Delaware for the Philadelphia Area, EPA believes that it is appropriate 
to consider the Area as a moderate nonattainment area with regard to 
the requirements of subpart 4. Sections 189(a) and (c) apply to 
moderate nonattainment areas and include the following requirements: 
(1) An approved permit program for construction of new and modified 
major stationary sources (section 189(a)(1)(A)); (2) an attainment 
demonstration (section 189(a)(1)(B)); (3) provisions for RACM and RACT 
(section 189(a)(1)(C)); (4) RFP and quantitative milestones (section 
189(c)); and (5) regulation of PM2.5 precursors (in general 
to meet RACM and RACT requirements and as specifically required for 
major stationary sources by section 189(e)).\14\ Other subpart 1 
requirements for attainment plans continue to apply to PM2.5 
nonattainment areas under subpart 4 and include the following: (1) 
Emissions inventories (section 172(c)(3)) and (2) contingency measures 
(section 172(c)(9)).
---------------------------------------------------------------------------

    \14\ EPA notes that this action does not address the NSR permit 
program requirements for the 1997 PM2.5 NAAQS. Delaware 
has addressed those requirements in a separate SIP submission which 
EPA approved on October 2, 2012 (77 FR 60053).
---------------------------------------------------------------------------

B. Pollutants Addressed

    Another consideration in evaluating the State's attainment plan 
from the perspective of the D.C. Circuit Court's decision and subpart 4 
is the approach to control of PM2.5 precursors in the 
Philadelphia Area. EPA's 2007 PM2.5 Implementation Rule 
included regulatory presumptions concerning certain PM2.5 
precursors applicable to attainment plans and control measures related 
to those plans. Specifically, in 40 CFR 51.1002, EPA provided that a 
state should address sources of PM2.5, sulfur dioxide 
(SO2), and NOX emissions in its attainment plan, 
but that a state was ``not required to address VOC [and ammonia] as . . 
. PM2.5 attainment plan precursor[s] and to evaluate sources 
of VOC [and ammonia] emissions in the State for control measures.''
    EPA established these presumptions concerning VOCs and ammonia in 
the 2007 PM2.5 Implementation Rule because of uncertainties 
regarding the emission inventories for these pollutants and the 
effectiveness of specific control measures in various regions of the 
country in reducing PM2.5 concentrations. EPA also left open 
the possibility, however, for such regulation of VOC and ammonia 
emissions as PM2.5 precursors in any nonattainment area 
where that was necessary for

[[Page 57577]]

purposes of attaining the 1997 PM2.5 NAAQS. EPA intended 
these to be rebuttable presumptions that either the state or EPA might 
reverse through notice and comment rulemaking, if that were necessary 
to provide for attainment in a given nonattainment area. These 
presumptions were not limited to emissions only from major stationary 
sources, but rather were presumptions applicable to precursor emissions 
from any sources of emissions within the area.\15\
---------------------------------------------------------------------------

    \15\ See 2007 PM2.5 Implementation Rule (72 FR 20586 
at 20589-97, April 25, 2007).
---------------------------------------------------------------------------

    EPA's approach to the consideration of PM2.5 precursors 
was called into question in the D.C. Circuit Court's decision in NRDC 
v. EPA. The D.C. Circuit Court's decision made specific reference to 
both section 189(e) and 40 CFR 51. 1002, and stated that:

    In light of our disposition, we need not address the 
petitioners' challenge to the presumptions in [40 CFR 51.1002] that 
volatile organic compounds and ammonia are not PM2.5 
precursors, as subpart 4 expressly governs precursor 
presumptions.\16\
---------------------------------------------------------------------------

    \16\ NRDC v. EPA, 706 F.3d 428, 437, n.10.

    Elsewhere in the D.C. Circuit Court's opinion, however, the D.C. 
---------------------------------------------------------------------------
Circuit Court explicitly observed that:

    Ammonia is a precursor to fine particulate matter, making it a 
precursor to both PM2.5 and PM10. For a 
PM10 nonattainment area governed by subpart 4, a 
precursor is presumptively regulated. See 42 U.S.C. Sec.  7513a(e) 
[section 189(e)].\17\
---------------------------------------------------------------------------

    \17\ NRDC v. EPA, 706 F.3d 428, 437, n.7.

    The D.C. Circuit Court reasoned that EPA's approach to precursors 
in the 2007 PM2.5 Implementation Rule had the effect of 
reversing the presumption embodied within subpart 4 that a state should 
address PM10 precursors unless the state made a specific 
showing why regulation of a particular precursor is not necessary.\18\
---------------------------------------------------------------------------

    \18\ Id.
---------------------------------------------------------------------------

    Although the D.C. Circuit Court did not vacate the 2007 
PM2.5 Implementation Rule, in this interim period while EPA 
seeks to respond to the D.C. Circuit Court's directive to apply subpart 
4, EPA believes it is prudent to evaluate whether an attainment plan 
adequately addresses precursors under subpart 4 without reliance on the 
precursor presumptions in 40 CFR 51.1002. The provisions of subpart 4 
do not define the term ``precursor'' for purposes of PM10, 
nor do they explicitly require the control of any specifically 
identified particulate matter precursor. However, section 189(e) 
indicates that consideration of precursors generally is necessary for 
attainment plans, and explicitly requires the control of the 
appropriate precursors from major stationary sources, unless there is a 
demonstration that such major stationary sources do not contribute 
significantly to nonattainment in the area.\19\ EPA has long recognized 
the scientific basis for concluding that there are multiple precursors 
to PM10, and in particular to PM2.5.\20\ 
PM2.5 chemical precursors include SO2, 
NOX, VOCs, and ammonia, although in a given nonattainment 
area, there may be technical or analytical limitations to the effective 
evaluation or control of one or more of these precursors for regulatory 
purposes. In the case of PM2.5, appropriate control of 
precursors is important because secondarily formed particles comprise 
the largest portion of ambient PM2.5 concentrations in many 
nonattainment areas.
---------------------------------------------------------------------------

    \19\ EPA notes that it has already addressed the requirements of 
subpart 4 for precursors, specifically within the context of the 
requirements of section 189(e), in the General Preamble. See 57 FR 
at 13539 and 13541-2.
    \20\ See, e.g., EPA's 2007 PM2.5 Implementation Rule 
at issue in the NRDC v. EPA case in which EPA discussed the fact 
that emissions of SO2, NOX, VOCs and ammonia 
are factual and scientific precursors to PM2.5, even if 
that does not necessarily mean that control of all of these 
precursors would be required for attainment plans, or needed for 
expeditious attainment of the NAAQS in all areas. See 72 FR 20586, 
at 20589-97.
---------------------------------------------------------------------------

    While subpart 4 expressly requires control of precursors from major 
stationary sources where direct PM from major sources is controlled 
unless certain conditions are met, other sources of precursors may also 
need to be controlled for the purposes of demonstrating attainment as 
expeditiously as practicable in a given area.\21\ Thus, assuming no 
presumptions under 40 CFR 51.1002, a state should evaluate all 
economically and technologically feasible control measures for direct 
PM2.5 emissions and PM2.5 precursor emissions, 
and should adopt those measures that are deemed reasonably available, 
i.e., those constituting RACM and RACT level emissions control for 
sources located in the area. EPA interprets subpart 4 to require 
analysis for control of precursors from all source categories in a 
given nonattainment area, unless there is a demonstration that 
controlling a precursor or precursors is not necessary for expeditious 
attainment of the NAAQS in the Area at issue.
---------------------------------------------------------------------------

    \21\ Thus, for example, states have developed and EPA has 
approved as meeting requirements of subpart 4, attainment plans that 
regulated NOX emissions from major stationary, mobile, 
and area sources in an area in order to provide for expeditious 
attainment of the applicable NAAQS. See, e.g., ``Approval and 
Promulgation of Implementation Plans for California--San Joaquin 
Valley PM10 Nonattainment Area; Serious Area Plan for 
Nonattainment of the 24-Hour and Annual PM10 Standards,'' 
(69 FR 30006, May 26, 2004) (approving a PM10 attainment 
plan that imposes controls on direct PM10 and 
NOX emissions and did not impose controls on 
SO2, VOC, or ammonia emissions).
---------------------------------------------------------------------------

    In the event that the State's plan includes controls on major 
stationary sources for PM10 in order to achieve timely 
attainment in the area, section 189(e) requires controls on major 
stationary sources of all PM10 precursors located within the 
area for all precursors, unless there is a showing that such sources do 
not contribute significantly to violations in the area. Thus, subject 
to section 189(e), EPA's existing interpretation of subpart 4 
requirements with respect to precursors in attainment plans for 
PM10 as set out in the General Preamble contemplates that 
states may develop attainment plans that regulate only those precursors 
that are necessary for purposes of attainment in the area in question, 
i.e., states may determine that only certain precursors need be 
regulated for attainment purposes.\22\ Courts have upheld this approach 
to the requirements of subpart 4 for PM10.\23\ EPA believes 
that application of this same approach to PM2.5 precursors 
under subpart 4 is appropriate and reasonable. Indeed, EPA has already 
taken action upon attainment plans for the 1997 PM2.5 NAAQS 
in other areas after carefully evaluating the state's conclusions 
regarding which PM2.5 precursors should be regulated in the 
area at issue.\24\
---------------------------------------------------------------------------

    \22\ Id.
    \23\ See, e.g., Assoc. of Irritated Residents v. EPA, et al., 
423 F.3d 989 (9th Cir. 2005).
    \24\ See, e.g., ``Approval and Promulgation of Implementation 
Plans; California; 2008 San Joaquin Valley PM2.5 Plan and 
2007 State Strategy,'' (76 FR 69896, November 9, 2011).
---------------------------------------------------------------------------

    For the reasons discussed in this section, EPA believes that 
Delaware's April 2008 attainment plan submission has adequately 
addressed PM2.5 precursors, both for purposes of RACM and 
RACT controls on appropriate sources for attainment of the NAAQS, and 
for purposes of section 189(e) with respect to precursors from major 
stationary sources. In the November 2012 proposed approval of 
Delaware's attainment plan for the Philadelphia Area, EPA already 
proposed to concur with the State's approach to regulation of 
PM2.5 precursors. As discussed in that NPR, the State, in 
accordance with EPA's existing 2007 PM2.5 Implementation 
Rule, addressed regulation of direct PM2.5, SO2, 
and NOX emissions and elected not to address VOC and ammonia 
emissions. Although in its SIP submission the State acknowledged that 
it was relying, in part, on the presumptions established

[[Page 57578]]

by EPA's implementation rule, the State provided additional substantive 
justification for its decisions not to regulate VOCs or ammonia as 
PM2.5 precursors in the Delaware attainment plan for the 
Philadelphia Area.\25\
---------------------------------------------------------------------------

    \25\ See Section 1.4 of the ``Delaware State Implementation Plan 
for Nonattainment of the PM2.5 National Ambient Air 
Quality Standard,'' dated March 20, 2008, submitted to EPA and 
included in the docket for this action (hereafter, Delaware SIP 
Submission).
---------------------------------------------------------------------------

    In light of the D.C. Circuit Court's decision in NRDC v. EPA, EPA 
has again reviewed Delaware's attainment plan, and EPA finds that 
Delaware's approach to PM2.5 precursors is appropriate for 
this Area and is consistent with the requirements of subpart 4 
concerning regulation of precursors without reliance on the 
presumptions of 40 CFR 51.1002. EPA's proposal to continue to approve 
the Delaware's attainment plan submission in this supplemental proposal 
is based on a number of considerations.
    First, quality-assured monitoring data establish that the 
Philadelphia Area has attained and continues to attain the 1997 annual 
PM2.5 NAAQS, through the approach to precursor pollutants 
adopted by the State in the submitted attainment plan.\26\ The State's 
SIP thus adequately addressed the attainment problem for this NAAQS 
through controls of direct PM2.5, SO2, and 
NOX. Given the Area's attainment of the 1997 annual 
PM2.5 NAAQS, it logically follows that no additional 
controls of other PM2.5 precursors are necessary for the 
Philadelphia Area to timely attain that NAAQS. Because EPA's 
longstanding approach to precursors under subpart 4, as explained in 
the General Preamble, authorizes a state to establish that it can 
attain the NAAQS expeditiously by focusing on some but not all 
precursors, EPA believes that Delaware's submitted attainment plan for 
the Philadelphia Area is consistent with this aspect of subpart 4.
---------------------------------------------------------------------------

    \26\ EPA notes that with inclusion of the most recent quality 
assured and certified data for 2011, the design value for the 
Philadelphia Area is now, based upon the years 2009-2011 is 13.7 
micrograms per cubic meter ([micro]g/m\3\). See http://www.epa.gov/airtrends/values.html.
---------------------------------------------------------------------------

    Second, EPA believes that the facts and circumstances support the 
State's decision not to treat VOC and ammonia as PM2.5 
precursors for purposes of RACM and RACT for attainment of the 1997 
annual PM2.5 NAAQS in the Philadelphia Area. With respect to 
VOC, the State already regulates VOC emissions from a broad spectrum of 
sources in order to meet the ozone NAAQS. This includes control of VOC 
emissions from sources within the Philadelphia Area, i.e., New Castle 
County in Delaware.\27\ EPA's General Preamble guidance on precursors 
under subpart 4 advised that a state, in determining whether to address 
VOCs for purposes of PM10, could take into consideration the 
existing regulation of VOC emissions for purposes of controlling other 
pollutants.\28\ With respect to ammonia, Delaware's SIP submission 
indicates that the emissions of ammonia within New Castle County are 
relatively low from all source categories. The 2002 base year inventory 
reflects that ammonia emissions in New Castle County were estimated at 
only 1,384 tons per year (tpy), and this amount is relatively small 
compared to other precursor emissions such as SO2 at 50,237 
tpy and NOX at 30,784 tpy. Moreover, those emissions of 
ammonia are distributed across various types of sources and thus are 
not the result of emissions from a common source or source 
category.\29\
---------------------------------------------------------------------------

    \27\ See Delaware SIP Submission, Section 1.4.2.
    \28\ See General Preamble, 57 FR 13358 and 13359-40.
    \29\ See Delaware SIP Submission, page 34 Table 3-1 and page 35 
Table 3-2.
---------------------------------------------------------------------------

    Third, EPA believes that the wide margin by which the area is 
attaining the 1997 annual PM2.5 NAAQS supports the 
conclusion that it was not necessary to treat VOCs and ammonia as 
PM2.5 precursors in this area differently for purposes of 
these NAAQS. The current air quality design value for New Castle County 
is 10.7 [micro]g/m\3\ (based on 2009-2011 air quality data), which is 
well below the 1997 annual PM2.5 NAAQS of 15 [mu]g/m\3\. 
More importantly, the current design value for the entire Philadelphia 
Area is 13.7 [mu]g/m\3\ (based on 2009-2011 air quality data) which is 
also well below the 1997 annual PM2.5 NAAQS of 15 [mu]g/
m\3\.
    In addition to the general approach to precursors, EPA's evaluation 
of Delaware's attainment plan for the Philadelphia Area also indicates 
that it is consistent with the specific precursor requirements of 
section 189(e) for major stationary sources. In prior PM10 
attainment plans under subpart 4, states have considered controls of 
PM10 precursors from various types of sources, including 
major stationary, mobile, and area sources in the area at issue, as 
necessary to attain the standard as expeditiously as practicable. Such 
consideration of potential precursor controls from all sources is 
relevant to the RACM and RACT and attainment demonstration components 
of an attainment plan under subpart 4. With respect specifically to 
controls of those precursors from major stationary sources, CAA section 
189(e) explicitly provides that all control requirements for major 
stationary sources of direct PM10 shall also apply to all 
PM10 precursors from those sources, except where EPA 
determines that emissions of the relevant precursors from the major 
stationary sources ``do not contribute significantly to PM10 
levels which exceed the standard in the area.''
    As the State has already attained the 1997 annual PM2.5 
NAAQS without additional controls of precursors from major stationary 
sources, EPA believes that the current control measures within the 
attainment plan are sufficient for purposes of satisfying section 
189(e). In EPA's General Preamble guidance for meeting subpart 4 
requirements, EPA advised that evaluation of a state's compliance with 
section 189(e) be based upon the specific facts and circumstances of 
the particular area at issue.\30\ EPA indicated that this determination 
should take into account any relevant information, including ``the 
significance of precursors to overall attainment.''\31\
---------------------------------------------------------------------------

    \30\ EPA has highlighted this point specifically within the 
context of the requirements of section 189(e) in the General 
Preamble. See 57 FR 13541-2.
    \31\ See General Preamble, 57 FR 13539.
---------------------------------------------------------------------------

    With respect to the State's decision not to address VOCs from major 
stationary sources for purposes of attaining the 1997 PM2.5 
NAAQS, EPA proposes to find that conclusion sufficient for purposes of 
satisfying section 189(e). The State's SIP submission indicated that it 
has already adequately regulated VOCs for other NAAQS and this is a 
valid consideration. Concerning precursor regulation under section 
189(e), EPA explicitly recommended in the General Preamble that 
existing controls of VOCs under other CAA statutory requirements may 
suffice to relieve a state from the need to adopt VOC controls as 
precursors to PM10 from major stationary sources under 
section 189(e).\32\ With respect to ammonia, the State's evaluation of 
the Philadelphia Area indicates that there are no major stationary 
sources of ammonia in New Castle County. Given that no such major 
sources exist, section 189(e) would not require any additional controls 
for ammonia. Thus, based upon these facts, EPA believes that the 
evaluation submitted by the State adequately demonstrates that ammonia 
controls for major stationary sources are not needed in the 
Philadelphia Area for purposes of section 189(e) for the 1997 annual 
PM2.5 NAAQS. In the alternative, in light of these facts and 
circumstances, and because the Area is currently attaining

[[Page 57579]]

the 1997 annual PM2.5 NAAQS, EPA proposes to find that 
emissions of VOC and ammonia from major stationary sources in Delaware 
do not contribute significantly to levels exceeding the 1997 annual 
PM2.5 NAAQS at this time in the Philadelphia Area for 
purposes of section 189(e).
---------------------------------------------------------------------------

    \32\ See General Preamble, 57 FR 13542.
---------------------------------------------------------------------------

    As to complying with section 189(e) for SO2 and 
NOX, EPA likewise proposes to find that Delaware has already 
imposed the requisite level of emissions controls on the relevant 
categories of major stationary sources located within the Philadelphia 
Area. EPA notes that it is not relying on one regulation previously 
approved into the Delaware SIP (Regulation 1142 Section 2.0) as part of 
the attainment demonstration for the 1997 PM2.5 NAAQS 
because it is not necessary to demonstrate attainment in this area. 
Through numerous existing regulations or other state actions, which are 
incorporated into Delaware's SIP, Delaware has regulated and is 
continuing to regulate major stationary sources of SO2 and 
NOX in the Philadelphia Area. Taking into consideration the 
existing regulation of major stationary sources, including those listed 
below (with the exception of Regulation 1142 Section 2.0), and the fact 
that the Area has already attained the 1997 PM2.5 NAAQS with 
its current approach to regulation of PM2.5 precursors from 
major stationary sources, EPA believes that it is reasonable to 
conclude in the context of this action that there is no need to revisit 
the attainment control strategy with respect to emissions of 
SO2 and NOX from major stationary sources in 
Delaware for the 1997 annual PM2.5 NAAQS for purposes of 
satisfying section 189(e). The SIP currently includes the following 
precursor controls on major stationary sources:
     Regulation 1146, Electric Generating Unit (EGU) Multi-
Pollutant Regulation, SO2 and NOX emission 
control (effective December 2007). SIP approved on August 28, 2008 (73 
FR 50723).
     Regulation 1148, Control of Stationary Combustion Turbine 
Electric Generating Unit Emissions, NOX emission control 
(effective January 2007). SIP approved on December 10, 2008 (73 FR 
66554).
     Regulation 1144, Control of Stationary Generator 
Emissions, SO2, PM, VOC, and NOX emission control 
(effective January 2006). SIP approved on May 29, 2008 (73 FR 23101).
     Regulation 1142, Section 1.0, Control of NOX 
Emissions from Industrial Boilers, NOX emission control 
(effective December 2010). SIP approved on June 4, 2010 (75 FR 31711).
     Regulation 1142, Section 2.0, Control of NOX 
Emissions from Industrial Boilers and Process Heaters at Petroleum 
Refineries, NOX emission control, New Castle County 
(effective June 2012). SIP approved May 5, 2012 (77 FR 28489).
     Facility and Unit shutdowns (see Table 4-3 in the Delaware 
submittal--NOX, SO2, PM2.5 emission 
reductions).
     Controls on Residential Woodstoves, 40 CFR Part 60 Subpart 
AAA--New Source Performance Standards (``NSPS'') for PM, VOC, and 
NOX emission control.
     Regulation 1113, Open Burning Controls, PM, VOC, and 
NOX emission control (effective October 2007). SIP approved 
on September 9, 2007 (72 FR 53686).
    EPA is not relying on Regulation 1142 Section 2.0 in this 
evaluation because it is not necessary for the purposes of attainment 
in this Area. As previously discussed, the Philadelphia Area is 
attaining the 1997 PM2.5 NAAQS. The current design value for 
the Philadelphia Area is 13.7 [mu]g/m\3\ and the 1997 PM2.5 
NAAQS is 15.0 [mu]g/m\3\ based on a 3-year average of annual mean 
PM2.5 concentrations. Regulation 1142 Section 2.0 applies to 
NOX emissions at petroleum refineries, but there is only one 
such petroleum refinery in Delaware. The source is separately subject 
to a Federally-enforceable Consent Decree and several Consent Decree 
addendums between the source and EPA which limit NOX 
emissions and require NOX control measures at several units 
at the refinery. In addition, the source has a Federally-enforceable 
permit which limits NOX emissions at the source to 2,525 tpy 
of NOX. Further, as previously mentioned, the 2002 base year 
inventory reflects that NOX emissions were 30,784 tpy in New 
Castle County such that the source's 2,525 tpy of NOX are 
relatively small in comparison and are already subject to Federally-
enforceable controls.
    After EPA's analysis of the source's permit limitations on 
NOX emissions, Federally-enforceable Consent Decree 
requirements, and present NOX emissions which are relatively 
small in comparison to NOX emissions in New Castle County, 
EPA concludes that additional control of NOX emissions at 
the source is not necessary to attainment or maintenance of the 1997 
PM2.5 NAAQS in the Philadelphia Area. Therefore, Regulation 
1142 Section 2.0 is not needed for Delaware's attainment demonstration 
to enable the Philadelphia Area to expeditiously attain as Philadelphia 
Area has already attained the 1997 annual PM2.5 NAAQS nor to 
show the Philadelphia Area can continue to attain the 1997 annual 
PM2.5 NAAQS.
    In summary, the determination whether the regulation of one or more 
PM2.5 precursors is necessary for attainment of the 1997 
PM2.5 NAAQS must ultimately be evaluated based on the 
particular facts and circumstances of each area, and upon the emissions 
reductions needed for that specific NAAQS. Delaware has already 
addressed emissions of direct PM2.5, SO2, and 
NOX in the Philadelphia Area and shown that the entire area 
has attained 1997 annual PM2.5 NAAQS without additional 
regulation of VOCs or ammonia in Delaware for that purpose. Moreover, 
Delaware has already identified those controls of PM2.5, 
SO2, and NOX that it relied upon for attainment 
of the 1997 annual PM2.5 NAAQS, and the fact that the Area 
is now attaining the NAAQS indicates that these controls were 
sufficient for this purpose. Under these circumstances, EPA believes 
that no further evaluation of this issue is necessary at this time for 
purposes of both attainment and section 189(e) and thus is continuing 
to propose approval of Delaware's approach to precursors, even taking 
into account the provisions of subpart 4 with the exception of 
Regulation 1142 Section 2.0 which EPA is not relying upon because it is 
not necessary for attainment of the 1997 annual PM2.5 NAAQS 
in this Area.

C. Emissions Inventory Requirement

    Section 172(c)(3) of the CAA requires that states submit a 
comprehensive, accurate, current inventory of actual emissions from all 
sources in the nonattainment area. Subpart 4 adds no additional 
emissions inventory requirements. In the General Preamble, EPA stated 
that section 172(c)(3) applies for purposes of subpart 4, which itself 
contains no additional emissions inventory requirements for purposes of 
PM10.\33\
---------------------------------------------------------------------------

    \33\ See General Preamble, 57 FR 13539. EPA notes, however, that 
under subpart 4 requirements states may need to submit updated 
emissions inventories to support later SIP submissions, such as SIP 
submissions to address the requirements for serious areas under 
section 189(b)(1), or the requirements for an extension of the 
serious area attainment date under section 188(e).
---------------------------------------------------------------------------

    EPA's remanded 2007 PM2.5 Implementation Rule required 
states to meet emissions inventory requirements, including a statewide 
emissions inventory of direct PM2.5 and of all 
PM2.5 precursors, any additional emissions inventory 
information needed to support an attainment demonstration

[[Page 57580]]

and RFP requirements, and a baseline (i.e., base year) emissions 
inventory suitable for the SIP planning requirements for the area at 
issue.\34\ As EPA explained in the preamble to the final 2007 
PM2.5 Implementation Rule, the emissions inventory 
requirement includes providing emissions information for direct 
PM2.5, SO2, NOX, VOCs, and ammonia in 
order to provide the information necessary for SIP planning, including 
the need to evaluate which PM2.5 precursors a state should 
regulate in a given nonattainment area.\35\
---------------------------------------------------------------------------

    \34\ See 40 CFR 51.1008.
    \35\ See 2007 PM2.5 Implementation Rule, 72 FR 20648. 
EPA noted that the obligation to address all of the scientific 
precursors of PM2.5 was a separate requirement needed to 
support various regulatory purposes, including the evaluation of 
whether relying on the rebuttable presumptions for precursors was 
correct in a given area.
---------------------------------------------------------------------------

    EPA's November 19, 2012 NPR already proposed approval of Delaware's 
submission with respect to emissions inventory requirements.\36\ EPA 
explained in that NPR Delaware's emissions inventory information was 
consistent with EPA's guidance and correctly included the emissions of 
direct PM2.5, SO2, NOX, VOCs, and 
ammonia.\37\ EPA further explained Delaware's sources of information 
for emissions for stationary sources, area sources, and mobile sources 
and indicated that the State's approach was appropriate. Moreover, EPA 
has already taken separate final action to approve the base year 
emissions inventory submitted by Delaware as part of its attainment 
plan for the 1997 PM2.5 NAAQS for the Philadelphia Area.\38\
---------------------------------------------------------------------------

    \36\ See 77 FR 69399, at 69403.
    \37\ For further details, see the TSD document entitled 
``Technical Support Document (TSD) for Emissions Inventories for the 
Delaware Nonattainment Area Particulate Matter (PM2.5) 
State Implementation Plan (SIP) Base Year Inventory,'' dated June 
16, 2012, The TSD is available in the docket online at 
www.regulations.gov, Docket Number EPA-R03-OAR-2010-0141.
    \38\ See (78 FR 10420, March 4, 2013).
---------------------------------------------------------------------------

    EPA believes that the DC Circuit Court's decision in NRDC v. EPA 
does not affect the emissions inventory requirements for the 1997 
PM2.5 NAAQS. The DC Circuit Court's remand of the 2007 
PM2.5 Implementation Rule to EPA with instructions to 
repromulgate implementation regulations consistent with subpart 4 would 
not result in additional emissions inventory requirements under subpart 
4 because none exist. The DC Circuit Court's comments on addressing 
PM2.5 precursors consistent with subpart 4 requirements also 
would not compel a different approach with respect to emissions 
inventories from that which EPA required under subpart 1. EPA's prior 
approach under subpart 1 already obligated states to include emissions 
of direct PM2.5, SO2, NOX, VOCs, and 
ammonia in such inventories, and provided no presumptions to exclude 
precursors from inventories. To the contrary, the emissions inventory 
requirement includes these precursors to assure adequate information to 
inform decisions about what pollutants to regulate for purposes of 
attaining the NAAQS in a given area.
    Because the emissions inventories submitted by Delaware for the 
attainment plan for the 1997 PM2.5 NAAQS already included 
emissions of direct PM2.5, SO2, NOX, 
VOCs, and ammonia, EPA concludes that there is no need to reexamine the 
emissions inventories for the Philadelphia Area.

D. Modeling

    As required, Delaware submitted modeling as part of the attainment 
plan for the Philadelphia Area. Delaware relied upon regional modeling 
that indicated the entire Philadelphia Area, including New Castle 
County, would attain the 1997 annual PM2.5 NAAQS by 2010. 
EPA carefully evaluated the State's modeling demonstration and 
concluded that it adequately supported the State's conclusion that the 
area would attain the 1997annual PM2.5 NAAQS by the 
projected attainment date.\39\
---------------------------------------------------------------------------

    \39\ For further details, see the TSD document entitled 
``Technical Support Document for the Modeling and Weight of Evidence 
Portions of the Delaware SIP for Attainment of the PM2.5 
NAAQS,'' dated June 15, 2012 (Modeling TSD). The Modeling TSD is 
available in the docket online at www.regulations.gov, Docket Number 
EPA-R03-OAR-2010-0141.
---------------------------------------------------------------------------

    Accordingly, EPA proposed approval of the State's modeling 
demonstration in the November 19, 2012 NPR.\40\ EPA explained that the 
State's modeling was consistent with EPA's guidance for such a 
demonstration, that the State had adequately articulated the bases for 
its modeling, and that the model supported the conclusion that the area 
would attain the 1997 annual PM2.5 NAAQS by the attainment 
date. Moreover, EPA noted that the model predicted that the 
Philadelphia Area would attain the NAAQS comfortably, with a 2009 
annual average design value predicted to be 13.3 ug/m\3\, and thus well 
below the level of the 1997 PM2.5 NAAQS by the attainment 
date of April 5, 2010. The model's predictions have proved accurate, 
and monitoring data showed the Philadelphia Area attained the 1997 
annual PM2.5 NAAQS by 2010, and continues to do so.\41\
---------------------------------------------------------------------------

    \40\ See 77 FR 69399, at 69404.
    \41\ For this reason, EPA issued both a determination of 
attainment and a clean data determination for the Philadelphia Area 
on May 16, 2012 (77 FR 28782).
---------------------------------------------------------------------------

    EPA believes that the decision in NRDC v. EPA does not affect EPA's 
proposed approval of the attainment demonstration modeling submitted as 
part of Delaware's attainment plan for the Philadelphia Area. First, 
section 189(a)(1)(B) provides that for a moderate nonattainment area, a 
state must submit either ``a demonstration (including air quality 
modeling) that the plan will provide for attainment by the applicable 
attainment date'' or ``a demonstration that attainment by such date is 
impracticable.'' Though not specifically intended to meet section 
189(a)(1)(B), the State's modeling demonstrated attainment by a date 
consistent with that applicable to a moderate nonattainment area.\42\ 
The state supported its demonstration with modeling consistent with 
EPA's guidance recommendations for this purpose.
---------------------------------------------------------------------------

    \42\ As discussed in section II.H. of this notice, EPA is 
proposing to find that the State's plan provided for attainment by a 
date appropriate for a moderate nonattainment area under subpart 4 
requirements, given the facts and circumstances of this area.
---------------------------------------------------------------------------

    Second, the modeling relied upon by the State addressed direct 
PM2.5 and PM2.5 precursors. As explained in more 
detail in the November 19, 2012 NPR, the state relied upon the 
Community Multi-scale Air Quality Model (CMAQ) modeling conducted by 
the Mid-Atlantic/Northeast Visibility Union (MANE-VU), using 
simulations of chemical reactions, emissions of PM2.5 and 
PM2.5 precursors, and a sophisticated meteorological model 
to evaluate PM2.5 concentrations over the eastern United 
States.\43\ The MANE-VU modeling included emissions of 
PM2.5, SO2, NOX, VOCs, and ammonia. 
The State also used EPA's recommended speciated modeled attainment test 
(``SMAT'') to evaluate ambient PM2.5 particles, including 
eight types of major components of ambient particles including 
sulfates, nitrates, ammonium, and organic carbon. Thus, the State 
likewise included evaluation of particles that result from emissions of 
SO2, NOX, VOCs, and ammonia through this means. 
Through this modeling, the State demonstrated attainment through 
analyses that did not omit consideration of either VOC or ammonia 
emissions as part of that process.
---------------------------------------------------------------------------

    \43\ See Modeling TSD at page 4.
---------------------------------------------------------------------------

    Because the modeling submitted by Delaware addressed direct 
PM2.5, SO2, NOX, VOCs, and 
ammonia, and correctly predicted that the area would attain 
the 1997 PM2.5 NAAQS by 2010, EPA concludes that there is no 
need to reexamine the attainment plan modeling

[[Page 57581]]

for the Philadelphia Area. Thus, EPA does not believe that the DC 
Circuit Court's decision in NRDC v. EPA should have any bearing on 
EPA's prior proposed approval of the modeling as meeting CAA 
requirements in this case.

E. Reasonably Available Control Measures/Reasonably Available Control 
Technology

    Another aspect of Delaware's submitted attainment plan potentially 
impacted by the NRDC v. EPA decision is whether Delaware has adequately 
addressed the requirement for RACM and RACT for the Philadelphia Area. 
EPA in this supplemental notice considers this requirement under 
subpart 4 as well as under subpart 1, and evaluates whether the subpart 
4 requirement for RACM and RACT would affect the control measures 
identified as part of the Delaware attainment plan for the Philadelphia 
Area. For the following reasons, EPA believes that Delaware's already 
submitted attainment plan for the Philadelphia Area adequately meets 
these requirements under subpart 4 for purposes of the 1997 
PM2.5 NAAQS with the exception of CAIR as previously 
proposed in the November 19, 2012 NPR, Regulation 1142 Section 2.0 for 
NOX emissions at petroleum refineries, and certain control 
measures for VOC emissions as discussed in more detail in this section.
    The general SIP planning requirements for nonattainment areas under 
subpart 1 include section 172(c)(1), which imposes on states an 
obligation to provide for the implementation of all RACM. Section 
172(c)(1) provides, parenthetically, that RACM also includes reductions 
from RACT. The terms RACM and RACT are not defined within subpart 1 or 
section 302. However, section 172(c) indicates that what constitutes 
RACM or RACT is related to what is necessary for attainment in a given 
area, as the provision explicitly requires that such measures must 
provide for attainment of the NAAQS in the area covered by the 
attainment plan.
    EPA based its remanded 2007 PM2.5 Implementation Rule on 
the general attainment plan requirement for RACM and RACT in section 
172(c). EPA included requirements for the process by which states 
should determine and establish what control measures would constitute 
RACM and RACT level controls for appropriate sources in a given 
nonattainment area for the 1997 PM2.5 NAAQS. Specifically, 
in 40 CFR 51.1010(a), EPA provided that a state should submit a 
demonstration that it had adopted all RACM and RACT ``necessary to 
demonstrate attainment as expeditiously as practicable and to meet RFP 
requirements.'' EPA also required states to include a ``list of the 
potential measures considered by the state, and information and 
analysis sufficient to support the state's judgment that it has adopted 
all RACM, including RACT.'' Moreover, in 40 CFR 51.1010(b), EPA 
provided that a state could determine that certain otherwise available 
control measures are not RACM or RACT for sources in the area if, 
considered cumulatively, the measures not adopted would not advance the 
attainment date in the area by at least one year.
    The SIP planning requirements specific to PM10 under 
subpart 4 likewise impose upon states an obligation to develop 
attainment plans that impose RACM and RACT on sources within a 
nonattainment area. Section 188(a)(1)(C) requires that states with 
areas classified as moderate nonattainment areas must have SIP 
provisions to assure that RACM and RACT level controls for 
PM10 are implemented by no later than four years after 
designation of the area.\44\ As with subpart 1, the terms RACM and RACT 
are not defined within subpart 4. Nor do the provisions of subpart 4 
specify how states are to meet the RACM and RACT requirements. However, 
EPA's longstanding guidance in the General Preamble provides 
recommendations for appropriate considerations for determining what 
control measures constitute RACM and RACT for purposes of meeting the 
statutory requirements of subpart 4.
---------------------------------------------------------------------------

    \44\ States with areas later classified as ``serious'' 
nonattainment areas under subpart 4 must also develop and submit 
later plans to meet additional requirements for serious areas, but 
those are not germane to this action for the reasons discussed in 
section II.A. of this notice.
---------------------------------------------------------------------------

    EPA's existing guidance for RACM and RACT under subpart 4 is 
comparable to the approach that EPA set forth in the 2007 
PM2.5 Implementation Rule. EPA's guidance for RACM under 
subpart 4 in the General Preamble includes: (1) A list of some 
potential measures for states to consider; (2) a statement of EPA's 
expectation that the state will provide a reasoned explanation for a 
decision not to adopt a particular control measure; (3) recognition 
that some control measures might be unreasonable because the emissions 
from the affected sources in the area are de minimis; (4) an emphasis 
on state evaluation of potential control measures for reasonableness, 
considering factors such as technological feasibility and the cost of 
control; and (5) encouragement that states evaluating potential control 
measures imposed upon municipal or other governmental entities also 
include consideration of the impacts on such entities, and the 
possibility of partial implementation when full implementation would be 
infeasible (e.g., phased implementation of measures such as road 
paving).\45\
---------------------------------------------------------------------------

    \45\ See General Preamble, 57 FR 13540-41.
---------------------------------------------------------------------------

    With respect to RACT requirements, EPA's existing guidance in the 
General Preamble: (1) Noted that RACT has historically been defined as 
``the lowest emission limit that a source is capable of meeting by the 
application of control technology that is reasonably available 
considering technological and economic feasibility;'' (2) noted that 
RACT generally applies to stationary sources, both stack and fugitive 
emissions; (3) suggested that major stationary sources be the minimum 
starting point for a state's RACT analysis; and (4) recommended that 
states evaluate RACT not only for major stationary sources, but for 
other source categories as needed for attainment and considering the 
feasibility of controls.\46\
---------------------------------------------------------------------------

    \46\ See General Preamble, 57 FR 13541.
---------------------------------------------------------------------------

    For both RACM and RACT, EPA notes that an overarching principle is 
that if a given control measure is not needed to attain the relevant 
NAAQS in a given area, then by definition that control measure would 
not be required as RACM or RACT because it would not be reasonable to 
impose controls that are not in fact needed for attainment purposes. In 
both the 2007 PM2.5 Implementation Rule interpreting the 
subpart 1 RACM and RACT requirements and the General Preamble making 
recommendations for the subpart 4 RACM and RACT requirements, the focus 
is upon the process to identify emissions sources, to evaluate 
potential emissions controls, and to impose those control measures that 
are reasonable and that are necessary to bring the area into attainment 
as expeditiously as practicable, but by no later than the applicable 
attainment date for the area.
    In its submitted attainment plan for the Philadelphia Area, 
Delaware addressed the RACM and RACT requirements of subpart 1 as 
interpreted in EPA's remanded 2007 PM2.5 Implementation 
Rule. As discussed in more detail in EPA's November 19, 2012 NPR, 
Delaware followed EPA's recommended process for evaluating which 
measures would constitute RACM and RACT in the Philadelphia Area. 
First, Delaware ascertained that emission controls of PM2.5, 
SO2, and NOX are necessary for attainment in this 
Area and that controls for ammonia or

[[Page 57582]]

additional emissions controls for VOCs are not.\47\ Second, Delaware 
evaluated the relevant emissions sources in the area, including ``point 
sources'' (i.e., major stationary sources), ``non-point sources'' 
(i.e., area sources), non-road mobile sources, and on-road mobile 
sources. Third, Delaware identified the control measures that it 
considered to be RACM and RACT for these types of sources in the 
Philadelphia Area because they were the measures that helped to provide 
for attainment by the 2010 attainment date. Fourth, Delaware identified 
and evaluated additional potential control measures and explained why 
adoption of those measures would not advance the attainment date by at 
least one year. Through this analytical approach, Delaware's attainment 
plan identified a suite of control measures already in the State's SIP 
that helped to bring the Philadelphia Area into attainment for the 1997 
PM2.5 NAAQS by the applicable attainment date and thus 
constituted RACM and RACT for the 1997 PM2.5 NAAQS for this 
Area.\48\
---------------------------------------------------------------------------

    \47\ As discussed in section II.B. of this notice, EPA is 
proposing to find that the State's determination of which precursors 
to address was adequately supported, given the facts and 
circumstances of this Area.
    \48\ EPA notes that because the State did not need to adopt 
additional control measures in order to provide for timely 
attainment in the area, reliance on existing federally enforceable 
measures already in the SIP was appropriate. Thus, the State's 
attainment plan submission identified those control measures for 
PM2.5, SO2, and NOX that achieved 
the local emissions reductions that helped the area to attain the 
1997 PM2.5 NAAQS and thus were sufficient to constitute 
RACM and RACT for sources in the area, with the exception of certain 
VOC control measures, Regulation 1142 Section 2.0 for petroleum 
refineries, and CAIR for EGUs.
---------------------------------------------------------------------------

    EPA has already proposed to find that the Delaware attainment plan 
for the Philadelphia Area meets the RACM and RACT requirements for the 
1997 PM2.5 NAAQS, with the exception of one measure that the 
state identified as a RACM and RACT measure, i.e., CAIR. EPA proposed 
this approval based upon the State's compliance with the requirements 
of the now remanded 2007 PM2.5 Implementation Rule, but EPA 
believes that the submitted attainment plan also meets the statutory 
RACM and RACT requirements of subpart 4 for several reasons.
    EPA's longstanding guidance for the determination of RACM and RACT 
under the statutory requirements of subpart 4 is analogous to that of 
subpart 1. EPA's General Preamble patterns the process for ascertaining 
RACM and RACT under subpart 4 after subpart 1, including comparable 
analytical steps and means for identifying relevant sources and 
potential control measures for those sources, and for evaluating 
whether potential control measures are reasonable based upon factors 
such as technological and economic feasibility. Most importantly, under 
either subpart, the state is required to determine RACM and RACT 
measures in light of the emissions reductions needed to bring the area 
in question into attainment. In other words, the emissions controls 
necessary to bring the area into attainment are by definition RACM or 
RACT for such area, and additional controls or other potential 
combinations of controls that would not be necessary for attainment or 
to advance attainment are not required for purposes of meeting this 
component of an attainment plan under either subpart 1 or subpart 4.
    As a result of the DC Circuit Court's decision in NRDC v. EPA, EPA 
has considered whether the control measures identified by the state as 
RACM and RACT measures (with the exception of certain VOC control 
measures, Regulation 1142 Section 2.0, and CAIR for EGUs) would meet 
the requirements of section 189(a)(1)(C). Given that the Philadelphia 
Area has attained the 1997 PM2.5 NAAQS through the measures 
already identified in the SIP submission, EPA believes that no further 
evaluation is necessary. A core principle of the RACM and RACT 
requirement is that, in addition to other considerations such as the 
technological feasibility, economic feasibility, and scheduling 
feasibility of potential control measures, states and EPA should 
evaluate the need for those control measures in order to provide for 
timely attainment of the NAAQS in question. In these circumstances, EPA 
believes that the attainment of the NAAQS by the projected date in 
2010, and the continued attainment of the NAAQS in the area, 
establishes that the attainment plan contains adequate RACM and RACT 
measures for purposes of the 1997 PM2.5 NAAQS. There is thus 
no need to consider control of any additional sources, or additional 
controls on already controlled sources, at this time. Accordingly, the 
DC Circuit Court's decision in NRDC v. EPA does not alter the EPA's 
view of the approvability of the attainment plan with respect to this 
requirement.
    However, EPA's review of the November 19, 2012 NPR concerning the 
RACM and RACT requirement does indicate the need to revise the proposal 
with respect to certain control measures included in the list of 
measures that Delaware identified as RACM and RACT measures for the 
1997 PM2.5 NAAQS in the Philadelphia Area. Delaware's 
attainment plan submission identified a number of control measures that 
are specifically intended to reduce only VOC emissions. The State noted 
that these measures intended for reduction of ozone ``could provide a 
PM2.5 benefit.'' \49\ Because the State also concluded that 
``Delaware is not regulating VOC emissions as PM2.5 
precursors under this SIP,'' however, EPA should not have proposed to 
approve those control measures that address only VOC emissions as RACM 
or RACT for the Philadelphia Area specifically for purposes of the 1997 
PM2.5 NAAQS. Accordingly, EPA is revising the list of 
measures that it is proposing to approve as RACM and RACT for the 1997 
PM2.5 NAAQS for the Philadelphia Area to remove the 
following measures listed in the November 19, 2012 NPR:
---------------------------------------------------------------------------

    \49\ See Delaware SIP submission at page 15.
---------------------------------------------------------------------------

     Regulation 1124, Section 11.0, Mobile Equipment Repair and 
Refinishing, VOC emission control.
     Regulation 1124, Section 33.0, Solvent Cleaning and 
Drying, VOC emission control.
     Regulation 1124, Section 36.0, Stage II Vapor Recovery, 
VOC emission control.
     Regulation 1124, Section 46.0, Crude Oil Lightering 
Operations, VOC emission control.
     Regulation 1141, Section 1.0, Architectural and Industrial 
Maintenance Coatings, VOC emission control.
     Regulation 1141, Section 2.0, Consumer Products, VOC 
emission control.
     Regulation 1141, Section 3.0, Portable Fuel Containers, 
VOC emission control.
    EPA is also proposing not to rely on Regulation 1142 Section 2.0 or 
CAIR for EGUs as RACM and RACT in Delaware for the 1997 
PM2.5 NAAQS but proposes to approve as RACM and RACT the 
other control measures, including State controls on EGUs, identified in 
Delaware's SIP Submittal, which were previously approved by EPA as part 
of the Delaware SIP (see 40 CFR 52.420(c)) or are otherwise Federally 
enforceable, because the Philadelphia Area has attained the 1997 
PM2.5 NAAQS by the attainment date.
    Regulation 1142 Section 2.0 is not needed in the Philadelphia Area 
as RACM and RACT and therefore EPA is proposing to exclude Regulation 
1142 Section 2.0 from this revised proposed approval. Regulation 1142 
Section 2.0 applies only to petroleum refineries. There is only one 
petroleum refinery source in Delaware subject to this regulation. This 
source's NOX emissions are restricted by a Federally-
enforceable

[[Page 57583]]

permit condition to 2,525 tons per year. The source is separately 
subject to a Federally-enforceable Consent Decree with several 
addendums as discussed above which independently limit NOX 
emissions and require NOX controls at the source, including 
units which would be subject to Regulation 1142 Section 2.0. Further, 
as previously mentioned, the 2002 base year inventory reflects that 
NOX emissions were 30,784 tpy in New Castle County such that 
the source's 2,525 tpy of NOX are relatively small in 
comparison and are already subject to Federally-enforceable controls. 
EPA has concluded that the source's NOX emissions are 
insignificant to emissions within Delaware for attaining and 
maintaining the 1997 PM2.5 NAAQS. Therefore, Regulation 1142 
Section 2.0 is neither required nor necessary for expeditious 
attainment of 1997 PM2.5 NAAQS, is not reasonably needed as 
a control measure, and is not required for RACM and RACT for the 
Philadelphia Area. EPA previously discussed in the November 19, 2012 
NPR that it is not relying on CAIR for purposes of meeting RACM and 
RACT in Delaware for the 1997 PM2.5 NAAQS and is not taking 
additional comment on that issue in this supplemental proposal. The 
RACM and RACT measures in Delaware for the 1997 PM2.5 NAAQS 
will be the remaining measures listed in the November 19, 2012 NPR with 
the exception of the control measures for VOC emissions identified 
above, Regulation 1142 Section 2.0, and CAIR for EGUs.\50\
---------------------------------------------------------------------------

    \50\ See 77 FR 69399 at 69406--07.
---------------------------------------------------------------------------

F. Reasonable Further Progress

    Another consideration in evaluating the State's attainment plan 
from the perspective of the D.C. Circuit Court's decision and subpart 4 
is the approach to meeting the reasonable further progress (RFP) 
requirements of the CAA. EPA's remanded 2007 PM2.5 
Implementation Rule included regulatory provisions for RFP based upon 
the subpart 1 statutory requirements of section 172(c)(2) in 40 CFR 
51.1009. The regulations provide that if a state's attainment plan 
demonstrated attainment within five years after designation, then no 
separate RFP demonstration is required. In the event that a state 
developed a plan with an attainment date projected beyond five years 
from designation, however, then the regulations require a specific RFP 
demonstration showing how the control measures in the plan will achieve 
reductions at specific milestone years of 2009 and 2012, as applicable. 
If a specific RFP plan were required, it must show generally linear 
progress in reducing emissions from the base year of the plan until the 
projected attainment year.
    Delaware's April 2008 SIP submission for the Philadelphia Area met 
the requirements of the 2007 PM2.5 Implementation Rule, and 
EPA has already proposed to approve it for this purpose. In particular, 
EPA noted that the attainment plan was designed to provide for 
attainment of the 1997 PM2.5 NAAQS within five years of 
designation and that attainment had in fact occurred. Accordingly, 
because the Philadelphia Area attained the 1997 PM2.5 NAAQS, 
EPA proposed to determine that the submission met the RFP requirement 
with the control measures in the plan and that there was no need for 
additional reductions for purposes of meeting any RFP requirement 
beyond that date.
    As a result of the DC Circuit Court's decision in NRDC v. EPA, EPA 
has considered whether Delaware's SIP submission would also meet the 
RFP requirements of subpart 4 in section 189(c). That section is 
comparable to the requirements of section 172(c)(1), in that it 
requires attainment plans under subpart 4 to meet a RFP requirement. 
However, section 189(c) also provides that an attainment plan should 
have ``quantitative milestones which are to be achieved every 3 years 
until the area is redesignated to attainment.'' EPA's General Preamble 
and Addendum provide guidance interpreting this statutory provision and 
are useful to evaluate this requirement of subpart 4.\51\
---------------------------------------------------------------------------

    \51\ See General Preamble, 57 FR 13539; Addendum, 59 FR 42015-
17.
---------------------------------------------------------------------------

    In particular, EPA's guidance recommendations with respect to 
section 189(c) include several salient features: (1) That the control 
measures comprising the RFP should be implemented and in place to meet 
the milestone requirement; (2) that it is reasonable for the three year 
periods for milestones to run from the date that the attainment plan 
submission is due; and (3) that the precise form quantitative 
milestones should take is not specified and they may take whatever form 
would allow progress to be quantified or measured adequately.\52\
---------------------------------------------------------------------------

    \52\ Merely as examples, EPA noted some potential approaches, 
such as percent implementation of control strategies, percent 
compliance with implemented control measures, and adherence to a 
compliance schedule. This list was clearly not exclusive and 
reflected that the purpose of such milestones is merely to provide 
an objective way to assess that the area is making progress towards 
attainment by the applicable attainment date. See Addendum, 59 FR 
42016.
---------------------------------------------------------------------------

    EPA believes that Delaware's SIP submission adequately meets these 
requirements for this Area for the 1997 PM2.5 NAAQS. First, 
although not presented as control measures that would achieve 
reductions by a specified three year milestone, the State's SIP 
submission contained control measures that were already implemented and 
in place and thus actually were achieving necessary emission reductions 
to meet RFP and milestone requirements at the appropriate point in 
time.
    Second, regardless of whether the statutory submission date for the 
attainment plan were that of subpart 1 or subpart 4, Delaware's 
attainment plan was achieving emission reductions by the date that 
would have been three years from such submission date. In other words, 
regardless of whether the SIP submission date could have been 18 months 
from the April 2005 date of the designation (i.e., October 2006), or 36 
months from such date (i.e., April 2008), the attainment plan submitted 
by Delaware in April 2008 included control measures that demonstrated 
attainment by 2009 and that were achieving emission reductions at that 
point in time (i.e., by a date three years from when the attainment 
plan was due under either subpart 1 or subpart 4, or in advance of that 
date).\53\ Because EPA has already determined that the Philadelphia 
Area has attained the 1997 PM2.5 NAAQS based on ambient data 
from 2007, 2008, and 2009, there would have been no requirement for a 
second RFP milestone at a six year point.
---------------------------------------------------------------------------

    \53\ EPA notes that at the time of the designations and at the 
time states were developing their attainment plans for the 1997 
PM2.5 NAAQS, EPA and states believed that the 
implementation of the PM2.5 NAAQS should proceed under 
subpart 1. At this juncture, EPA believes that it would be 
inappropriate to consider the statutory SIP submission date of 
subpart 4 to be the operative date retroactively. In this instance, 
it would make no difference with respect to the approvability of the 
attainment plan in any event.
---------------------------------------------------------------------------

    Third, Delaware's SIP submission provided information sufficient to 
quantify the amount of emission reductions being achieved. Although not 
presented for purposes of showing the amount of reductions for a 
specific three year milestone requirement, the State's SIP submission 
nonetheless quantified the amount of emission reduction to be achieved 
through the attainment plan, by pollutant, by 2009.\54\ Thus, the 
attainment plan did quantify the emission reductions that would occur 
at a point in time that was appropriate for a three year milestone,

[[Page 57584]]

regardless of what the statutory SIP submission date was under either 
subpart 1 or subpart 4.
---------------------------------------------------------------------------

    \54\ See Delaware SIP submission, page 93, Table 7-1. Comparing 
the 2002 (base year) and 2009 (attainment year) emissions estimates 
for New Castle County, the information provided by Delaware 
indicated reductions of PM2.5 (415 tpy or 12.1%,), 
SO2 (36,102 tpy or 71.9%), and NOX (8,941 tpy 
or 29.1%).
---------------------------------------------------------------------------

    Finally, EPA notes that statutory RFP and milestone requirements of 
section 189(c) are intended to assure reasonable progress towards 
attainment. Once an area has already attained the NAAQS, as is the case 
with the Philadelphia Area for the 1997 PM2.5 NAAQS, the 
intended purpose for emissions reductions to meet an RFP or milestone 
requirement is no longer relevant. EPA thus believes that the RFP and 
milestone requirements are functionally moot once the area has attained 
the NAAQS. Accordingly, the DC Circuit Court's decision in NRDC v. EPA 
does not alter the EPA's view of the approvability of the attainment 
plan with respect to the RFP and milestone requirements of subpart 4.

G. Contingency Measures

    In its SIP submission, Delaware addressed the contingency measure 
requirements for the Philadelphia Area and EPA has proposed to approve 
the State's attainment plan with respect to these requirements. The DC 
Circuit Court's decision in NRDC v. EPA should have no impacts on the 
contingency measure requirements for purposes of the PM2.5 
NAAQS. Section 172(c)(9) imposes the contingency measure requirement 
for attainment plans and it applies to both subpart 1 and subpart 4. 
The contingency measure requirement is not superseded or subsumed by 
subpart 4, and thus there would be no change in this requirement as a 
result of the NRDC v. EPA decision. In addition, EPA notes that it has 
already determined that the Philadelphia Area has attained the 1997 
PM2.5 NAAQS and thus the continued need for contingency 
measures for failure to meet RFP or to attain by the attainment date is 
moot at this juncture.

H. Attainment Date

    In its SIP submission, Delaware provided a demonstration of 
attainment of the 1997 PM2.5 NAAQS in the Philadelphia Area 
by 2010. Based upon current ambient air quality monitoring data, the 
Philadelphia Area in fact attained the 1997 PM2.5 NAAQS by 
2010 and continues to be in attainment of those NAAQS.\55\
---------------------------------------------------------------------------

    \55\ The most recent design value for the Philadelphia Area, 
based upon the years 2009-2011, is 13.7 [micro]g/m\3\. See http://www.epa.gov/airtrends/values.html.
---------------------------------------------------------------------------

    Under either subpart 1 or subpart 4 requirements, a state is 
required to develop an attainment plan that provides for attainment 
``as expeditiously as practicable.'' Under section 172(a)(2)(A), 
however, subpart 1 requirements impose somewhat different requirements, 
providing that the area must attain as expeditiously as practicable, 
but not later than 5 years from the date of designation, with the 
possibility of extensions of up to 10 years from the date of 
designation under specified conditions. Under subpart 4, however, 
Congress created different attainment date requirements for areas 
classified as ``moderate'' or ``serious'' nonattainment areas. Most 
relevant for this proposal, however, under Section 188(c)(1), a state 
with a moderate nonattainment area must provide for attainment as 
expeditiously as practicable, but not later than the end of the sixth 
calendar year after the date of designation.
    In the case of Delaware's attainment plan for the Philadelphia 
Area, EPA believes that the State has met not only the generally 
applicable attainment date requirements of subpart 1, but also met the 
requirements specific to particulate matter in subpart 4. EPA's 
designations for the 1997 PM2.5 NAAQS were effective on 
April 5, 2005. In the remanded 2007 PM2.5 Implementation 
Rule, EPA indicated that states should develop attainment plans that 
provided for attainment as expeditiously as practicable, but not later 
than 5 years after designation, unless an extension of the attainment 
date was warranted. The State developed an attainment plan that 
demonstrated attainment of the NAAQS by 2010 and the Area in fact 
attained by the targeted date. Under section 188(c)(1), a state with a 
moderate area could, so long as it showed expeditious attainment of the 
NAAQS, demonstrate attainment up until the end of the sixth calendar 
year following the designation of the area, i.e., until the end of 
2011. Thus, the demonstration that Delaware made here that the Area 
would attain the 1997 PM2.5 NAAQS by the end of 2010 would 
constitute a demonstration that the Area attained as expeditiously as 
practicable, but not later than the end of 2011 as required by subpart 
4.
    Based upon the foregoing reasoning, EPA proposes to find that 
Delaware's attainment plan SIP submission for the Philadelphia Area 
factually and functionally meets the attainment date requirements for 
nonattainment areas under subpart 4, in addition to the requirements 
under subpart 1. EPA does not believe that the D.C. Circuit Court's 
decision in NRDC v. EPA should have any bearing on EPA's prior proposed 
approval of the attainment date supported by the attainment plan 
submission as meeting CAA requirements.

III. Motor Vehicle Emissions Budgets

    EPA's November 19, 2012 NPR also proposed approval of Delaware's 
MVEBs for the Philadelphia Area (i.e., New Castle County in Delaware). 
However, in the TSD associated with the November 19, 2012 NPR, MVEBs 
for 2012 were inadvertently used instead of 2009. The correct MVEBs for 
2009 are shown in Table 1. Delaware's April 25, 2012 SIP submittal also 
included Delaware's 2012 MVEBs which were the numbers used in the TSD 
associated with the November 19, 2012 NPR for 2009. The corrected MVEBs 
for 2012 are shown in Table 2.

  Table 1--Delaware's 2009 Motor Vehicle Emissions Budget for the 1997 PM2.5 NAAQS Attainment Plan in Tons per
                                                      Year
----------------------------------------------------------------------------------------------------------------
                        Plan Submittal                          Milestone Year       PM2.5             NOX
----------------------------------------------------------------------------------------------------------------
Attainment Plan..............................................            2009              257            8,448
----------------------------------------------------------------------------------------------------------------


  Table 2. Delaware's 2012 Motor Vehicle Emissions Budget for the 1997 PM2.5 NAAQS Attainment Plan in Tons per
                                                      Year
----------------------------------------------------------------------------------------------------------------
                        Plan Submittal                             Out Year          PM2.5             NOX
----------------------------------------------------------------------------------------------------------------
Attainment Plan..............................................            2012              199            6,273
----------------------------------------------------------------------------------------------------------------


[[Page 57585]]

    In this supplemental proposal, EPA proposes to approve Delaware's 
MVEBs for 2009 (Table 1) and also proposes to approve Delaware's MVEBs 
for 2012 (Table 2) which Delaware had requested EPA to approve in its 
April 25, 2012 SIP submission. A supplemental TSD, dated August 26, 
2013, discusses EPA's analysis and support for this proposal approving 
Delaware's MVEBs for 2009 and 2012 and is available on line at 
www.regulations.gov, Docket No. EPA-R03-OAR-2010-0141.
    Accordingly, EPA continues to believe that the MVEBs for 2009 meet 
applicable requirements for such budgets for purposes of the 1997 
annual PM2.5 NAAQS and asserts the MVEBs for 2012 likewise 
meet applicable requirements for budgets for transportation conformity 
purposes for New Castle County in Delaware. As a result of EPA's 
finding, New Castle County must use the MVEBs from the April 25, 2012 
SIP submittal for future conformity determinations for the 1997 annual 
PM2.5 NAAQS.

IV. Summary of Reproposal

    Based on the foregoing reasons, EPA proposes to approve the 
Delaware attainment plan submitted for the Philadelphia Area. EPA 
believes that the attainment plan submitted by Delaware for the 
Philadelphia Area, though not expressed in terms of subpart 4 
requirements, substantively meets the requirements of that subpart for 
purposes of approval under section 110(k). EPA is also updating 
information related to EPA's proposed approval of the MVEBs for New 
Castle County, Delaware, solely for purposes of transportation 
conformity for this Area.
    EPA solicits comments on this supplemental proposal, but only with 
respect to the specific issues raised in this rulemaking action. EPA is 
not seeking comment on any other aspect of the November 19, 2012 NPR as 
those issues have already been adequately addressed. The purpose of 
this supplemental proposal is limited to review of the attainment plan 
submitted by Delaware for the Philadelphia Area in light of the D.C. 
Circuit Court's decision in NRDC v. EPA, EPA's further evaluation of 
Delaware's submitted attainment plan, and EPA's desire for public input 
into how it should proceed in light of the NRDC v. EPA decision when 
acting on the pending attainment plan for this Area for the 1997 
PM2.5 NAAQS.

V. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the CAA and applicable 
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, EPA's role is to approve state choices, 
provided that they meet the criteria of the CAA. Accordingly, this 
action merely proposes to approve state law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Order 
12866 (58 FR 51735, October 4, 1993);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA; and
     Does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this supplemental proposed rule pertaining to the 
Delaware 1997 annual PM2.5 attainment plan for the 
Philadelphia Area, does not have tribal implications as specified by 
Executive Order 13175 (65 FR 67249, November 9, 2000), because the SIP 
is not approved to apply in Indian country located in the state, and 
EPA notes that it will not impose substantial direct costs on tribal 
governments or preempt tribal law.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Nitrogen dioxide, 
Ozone, Particulate matter, Reporting and recordkeeping requirements, 
Sulfur oxides, Volatile organic compounds.

    Authority:  42 U.S.C. 7401 et seq.

    Dated: September 12, 2013.
W.C. Early,
Acting Regional Administrator, Region III.
[FR Doc. 2013-22829 Filed 9-18-13; 8:45 am]
BILLING CODE 6560-50-P