Document ID: EPA-R04-OAR-2012-0081-0001
Agency: epa
Document Type: Proposed Rule
Title: Approvals and Promulgations of Implementation Plans: Mississippi; New Source Review-Prevention of Significant Deterioration; Fine Particulate Matter
Posted Date: 2012-07-23T04:00Z

[Federal Register Volume 77, Number 141 (Monday, July 23, 2012)]
[Proposed Rules]
[Pages 43032-43039]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-17893]

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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R04-OAR-2012-0081; FRL-9702-8]

Approval and Promulgation of Implementation Plans; Mississippi: 
New Source Review-Prevention of Significant Deterioration; Fine 
Particulate Matter (PM2.5)

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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

SUMMARY: EPA is proposing to approve a revision to the Mississippi 
State Implementation Plan (SIP), submitted by the Mississippi 
Department of Environmental Quality (MDEQ) through the Division of Air 
Pollution Control to EPA on May 12, 2011. The SIP revision modifies 
Mississippi's New Source Review (NSR) Prevention of Significant 
Deterioration (PSD) program. The May 12, 2011, SIP revision 
incorporates by reference the federal NSR PSD requirements for the fine 
particulate matter (PM2.5) national ambient air quality 
standards (NAAQS) as amended in EPA's 2008 NSR PM2.5 
Implementation Rule (hereafter referred to as the ``NSR 
PM2.5 Rule'') and the 2010 PM2.5 PSD Increment, 
Significant Impact Levels (SILs) and Significant Monitoring 
Concentration (SMC) Rule (hereafter referred to the ``PM2.5 
PSD Increment-SILs-SMC Rule'') into the Mississippi SIP. EPA is 
proposing to approve portions of Mississippi's SIP revision because the 
Agency has preliminarily determined that the provisions proposed for 
approval are consistent with section 110 of the Clean Air Act (CAA or 
Act) and EPA regulations regarding NSR permitting.

DATES: Comments must be received on or before August 22, 2012.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2012-0081 by one of the following methods:
    1. www.regulations.gov: Follow the on-line instructions for 
submitting comments.
    2. Email: R4-RDS@epa.gov.
    3. Fax: (404) 562-9019.
    4. Mail: EPA-R04-OAR-2012-0081, Regulatory Development Section, Air 
Planning Branch, Air, Pesticides and Toxics Management Division, U.S. 
Environmental Protection Agency, Region 4, 61 Forsyth Street SW., 
Atlanta, Georgia 30303-8960.
    5. Hand Delivery or Courier: Ms. Lynorae Benjamin, Chief, 
Regulatory Development Section, Air Planning Branch, Air, Pesticides 
and Toxics Management Division, U.S. Environmental Protection Agency, 
Region 4, 61 Forsyth Street SW., Atlanta, Georgia 30303-8960. Such 
deliveries are only accepted during the Regional Office's normal hours 
of operation. The Regional Office's official hours of business are 
Monday through Friday, 8:30 to 4:30, excluding federal holidays.
    Instructions: Direct your comments to Docket ID No. ``EPA-R04-OAR-
2012-0081.'' 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 through 
www.regulations.gov or email, information that you consider to be CBI 
or otherwise protected. 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. For additional information about EPA's public 
docket visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.
    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 at the Regulatory Development Section, Air Planning 
Branch, Air, Pesticides and Toxics Management Division, U.S. 
Environmental Protection Agency, Region 4, 61 Forsyth Street SW., 
Atlanta, Georgia 30303-8960. EPA requests that if at all possible, you 
contact the person listed in the FOR FURTHER INFORMATION CONTACT 
section to schedule your inspection. The Regional Office's official 
hours of business are Monday through Friday, 8:30 to 4:30, excluding 
federal holidays.

FOR FURTHER INFORMATION CONTACT: For information regarding the 
Mississippi SIP, contact Ms. Twunjala Bradley, Regulatory Development 
Section, Air Planning Branch, Air, Pesticides and Toxics Management 
Division, U.S. Environmental Protection Agency, Region 4, 61 Forsyth 
Street SW., Atlanta, Georgia 30303-8960. Ms. Bradley's telephone number 
is (404) 562-9352; email address: bradley.twunjala@epa.gov. For 
information regarding NSR, contact Ms. Yolanda Adams, Air Permits 
Section, at the same address above. Ms. Adams' telephone number is 
(404) 562-9241; email address: adams.yolanda@epa.gov. For information 
regarding the PM2.5 NAAQS, contact Mr. Joel Huey, Regulatory 
Development Section, at the same address above. Mr. Huey's telephone 
number is (404) 562-9104; email address: huey.joel@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. What action is EPA proposing?
II. What is the background for EPA's proposed action?
III. What are the NSR implementation requirements for the 
PM2.5 NAAQS?
IV. What is EPA's analysis of Mississippi's SIP revision?
V. Proposed Action
VI. Statutory and Executive Order Reviews

I. What action is EPA proposing?

    On May 12, 2011, MDEQ submitted a SIP revision to EPA for approval 
into the Mississippi SIP to incorporate by

[[Page 43033]]

reference (IBR) \1\ federal NSR PSD permitting requirements. 
Mississippi's SIP revision makes changes to its Air Quality Regulations 
in Air Pollution Control, Section 5 (APC-S-5)--Regulations for the 
Prevention of Significant Deterioration of Air Quality These rule 
changes were provided to comply with federal NSR permitting provisions 
related to the implementation of the PM2.5 NAAQS for the PSD 
program as promulgated in the NSR PM2.5 Rule entitled 
``Implementation of the New Source Review (NSR) Program for Particulate 
Matter Less than 2.5 Micrometers (PM2.5), '' Final Rule, 73 
FR 28321 (May 16, 2008) and the PM2.5 PSD Increment-SILs-SMC 
Rule entitled ``Prevention of Significant Deterioration (PSD) for 
Particulate Matter Less Than 2.5 Micrometers (PM2.5)--
Increments, Significant Impact Levels SILs and Significant Monitoring 
Concentration (SMC),'' Final Rule,'' 75 FR 64864, (October 20, 2010). 
Additionally, Mississippi's SIP revision requests that EPA remove from 
the SIP the exclusion language at APC-S-5 (2.7) regarding the NSR 
PM2.5 Rule provisions. Pursuant to section 110 of the CAA, 
EPA is proposing to approve these changes, with the exception of the 
two elements discussed below, into the Mississippi SIP.
---------------------------------------------------------------------------

    \1\ Throughout this document IBR means incorporate or 
incorporates by reference.
---------------------------------------------------------------------------

    The two elements of MDEQ's May 12, 2011, SIP revision which EPA is 
not proposing to approve in this action are: (1) incorporation of the 
SIL thresholds promulgated in EPA's PM2.5 PSD Increment-
SILs-SMC Rule, 75 FR 64864 (October 20, 2010); and (2) incorporation of 
the provision regarding the applicability of the term ``particulate 
matter emissions'' when accounting for condensable particles in 
applicability determinations and in establishing emissions limitations 
in PSD permits. More details are provided in Sections II-IV below.

II. What is the background for EPA's proposed action?

    Today's proposed action to revise the Mississippi SIP relates to 
relates to EPA's NSR PM2.5 Rule and the PM2.5 PSD 
Increment-SILs-SMC Rule. In the NSR PM2.5 Rule, EPA 
finalized regulations to implement the NSR program for the 
PM2.5 NAAQS. As a result of EPA's final NSR PM2.5 
Rule, states were required to submit SIP revisions to EPA no later than 
May 16, 2011, to address these requirements for both the PSD and 
Nonattainment NSR (NNSR) programs. EPA's PM2.5 PSD 
Increment-SILs-SMC Rule established PSD increments, SILs and SMC which 
address additional components for making PSD permitting determinations 
for PM2.5 NAAQS. These requirements address air quality 
modeling and monitoring provisions for fine particle pollution in areas 
protected by the PSD program (that is attainment or unclassifiable/
attainment areas for the NAAQS). EPA's October 20, 2010, final 
rulemaking that approved the PM2.5 PSD Increment-SILs-SMC 
Rule required states to submit SIP revisions to adopt the required PSD 
increments by July 20, 2012. Together these two rules address the NSR 
permitting requirements needed to implement the PM2.5 NAAQS. 
Mississippi's May 12, 2011, SIP revision IBR into the Mississippi SIP 
(at APC-S-5), the PSD requirements promulgated in these two rules to be 
consistent with federal regulations for the PM2.5 NAAQS. 
More detail on the NSR PM2.5 Rule and the PM2.5 
PSD Increment-SILs-SMC Rule can be found in EPA's May 16, 2008, and 
October 20, 2010, final rules respectively and are summarized below.

A. Fine Particulate Matter and the NAAQS

    Fine particles in the atmosphere are made up of a complex mixture 
of components. Common constituents include sulfate; nitrate; ammonium; 
elemental carbon; a great variety of organic compounds; and inorganic 
material (including metals, dust, sea salt, and other trace elements) 
generally referred to as ``crustal'' material, although it may contain 
material from other sources. Airborne particulate matter (PM) with a 
nominal aerodynamic diameter of 2.5 micrometers or less (a micrometer 
is one-millionth of a meter, and 2.5 micrometers is less than one-
seventh the average width of a human hair) are considered to be ``fine 
particles'' and are also known as PM2.5. ``Primary'' 
particles are emitted directly into the air as a solid or liquid 
particle (e.g., elemental carbon from diesel engines or fire 
activities, or condensable organic particles from gasoline engines). 
``Secondary'' particles (e.g., sulfate and nitrate) form in the 
atmosphere as a result of various chemical reactions.
    The health effects associated with exposure to PM2.5 
include potential aggravation of respiratory and cardiovascular disease 
(i.e., lung disease, decreased lung function asthma attacks and certain 
cardiovascular issues). Epidemiological studies have indicated a 
correlation between elevated PM2.5 levels and premature 
mortality. Groups considered especially sensitive to PM2.5 
exposure include older adults, children, and individuals with heart and 
lung diseases. For more details regarding health effects and 
PM2.5 see EPA's Web site at http://www.epa.gov/oar/particlepollution/ (See heading ``Health and Welfare'').
    On July 18, 1997, EPA revised the NAAQS for PM to add new standards 
for fine particles, using PM2.5 as the indicator. 
Previously, EPA used PM10 (inhalable particles smaller than 
or equal to 10 micrometers in diameter) as the indicator for the PM 
NAAQS. EPA established health-based (primary) annual and 24-hour 
standards for PM2.5, setting an annual standard at a level 
of 15 micrograms per cubic meter ([mu]g/m\3\) and a 24-hour standard at 
a level of 65 [mu]g/m\3\. See 62 FR 38652. At the time the 1997 primary 
standards were established, EPA also established welfare-based 
(secondary) standards identical to the primary standards. The secondary 
standards are designed to protect against major environmental effects 
of PM2.5, such as visibility impairment, soiling, and 
materials damage. On October 17, 2006, EPA revised the primary and 
secondary 24-hour NAAQS for PM2.5 to 35 [mu]g/m\3\ and 
retained the existing annual PM2.5 NAAQS of 15.0 [mu]g/m\3\. 
See 71 FR 61236.

B. What is the NSR program?

    The CAA NSR program is a preconstruction review and permitting 
program applicable to certain new and modified stationary sources of 
air pollutants regulated under the CAA. The program includes a 
combination of air quality planning and air pollution control 
technology requirements. The CAA NSR program is composed of three 
separate programs: PSD, NNSR, and Minor NSR. PSD is established in part 
C of title I of the CAA and applies in areas that meet the NAAQS 
(``attainment areas'') as well as areas where there is insufficient 
information to determine if the area meets the NAAQS (``unclassifiable 
areas''). The NNSR program is established in part D of title I of the 
CAA and applies in areas that are not in attainment of the NAAQS 
(``nonattainment areas''). The Minor NSR program addresses construction 
or modification activities that do not qualify as ``major'' and applies 
regardless of the designation of the area in which a source is located. 
Together, these programs are referred to as the NSR program. EPA 
regulations governing the implementation of these programs are 
contained in 40 CFR sections 51.160-.166; 52.21, .24; and, part 51, 
appendix S. Section 109 of the CAA requires EPA to promulgate a primary 
NAAQS to protect public

[[Page 43034]]

health and a secondary NAAQS to protect public welfare. Once EPA sets 
those standards, states must develop, adopt, and submit a SIP to EPA 
for approval that includes emission limitations and other control 
measures to attain and maintain the NAAQS. See CAA section 110. Each 
SIP is also required to include a preconstruction review program for 
the construction and modification of any stationary source of air 
pollution to assure the maintenance of the NAAQS. The applicability of 
the PSD program to a major stationary source must be determined in 
advance of construction and is a pollutant-specific determination. Once 
a major source is determined to be subject to the PSD program (and thus 
is a ``PSD source''), among other requirements, it must undertake a 
series of analyses to demonstrate that it will use the best available 
control technology and will not cause or contribute to a violation of 
any NAAQS or increment. Mississippi's May 12, 2011, SIP submittal 
revises Mississippi's PSD program.

III. What are the NSR implementation requirements for the PM2.5 NAAQS?

A. NSR PM2.5 Rule

    On May 16, 2008, EPA finalized the NSR PM2.5 Rule to 
implement the PM2.5 NAAQS, including changes to the NSR 
program.\2\ See 73 FR 28321. The NSR PM2.5 Rule revised the 
federal NSR program requirements to establish the framework for 
implementing preconstruction permit review for the PM2.5 
NAAQS in both attainment and nonattainment areas. Specifically, the NSR 
PM2.5 Rule established NSR requirements to implement the 
PM2.5 NAAQS that: (1) Require NSR permits to address 
directly emitted PM2.5 and precursor pollutants; (2) 
establish significant emission rates for direct PM2.5 and 
precursor pollutants (including sulfur dioxide (SO2) and 
nitrogen oxides (NOX)); (3) establish PM2.5 
emission offsets; (4) provide exceptions to the PM10 
grandfathering policy; and, (5) require states to account for gases 
that condense to form particles (condensables) in PM2.5 and 
PM10 emission limits in PSD or NNSR permits. Additionally, 
the NSR PM2.5 Rule authorized states to adopt provisions in 
their nonattainment NSR rules that would allow interpollutant offset 
trading. Mississippi's May 12, 2011, SIP revision addresses the PSD 
permitting requirements promulgated in EPA's May 16, 2008, NSR 
PM2.5 Rule.\3\ A few key issues described in greater detail 
below include: the PM10 surrogate and grandfathering policy, 
the condensable provision and the NOX precursor 
insignificance demonstration.
---------------------------------------------------------------------------

    \2\ On November 1, 2005, EPA proposed a rule to implement the 
1997 PM2.5 NAAQS, including proposed revisions to the NSR 
program. See 70 FR 65984.
    \3\ Mississippi's May 12, 2011, SIP revision only addresses the 
State's PSD permitting program and does not adopt the NNSR 
permitting requirements for PM2.5 emission offsets, 
condensable provision or the discretionary interpollutant trading 
policy and ratios promulgated in the 2008 NSR PM2.5 Rule. 
Moreover Mississippi is attainment for the 1997 annual and 2006 24-
hour PM2.5 NAAQS.
---------------------------------------------------------------------------

1. PM10 Surrogate and Grandfathering Policy
    After EPA promulgated the NAAQS for PM2.5 in 1997 (62 FR 
38652, July 18, 1997), the Agency issued a guidance document entitled 
``Interim Implementation of New Source Review Requirements for 
PM2.5.'' John S. Seitz, EPA, October 23, 1997 (the ``Seitz 
memo''). The Seitz memo was designed to help states implement NSR 
requirements pertaining to the new PM2.5 NAAQS in light of 
technical difficulties posed by PM2.5 at that time. 
Specifically, the Seitz memo stated: ``PM-10 may properly be used as a 
surrogate for PM-2.5 in meeting NSR requirements until these 
difficulties are resolved.'' EPA also issued a guidance document 
entitled ``Implementation of New Source Review Requirements in PM-2.5 
Nonattainment Areas'' (the ``2005 PM2.5 NNSR Guidance''), on 
April 5, 2005, the date that EPA's PM2.5 nonattainment area 
designations became effective for the 1997 NAAQS. The 2005 
PM2.5 NNSR Guidance provided direction regarding 
implementation of the nonattainment major NSR provisions in 
PM2.5 nonattainment areas in the interim period between the 
effective date of the PM2.5 nonattainment area designations 
(April 5, 2005) and EPA's promulgation of final PM2.5 NNSR 
regulations. Besides re-affirming the continuation of the 
PM10 Surrogate Policy for PM2.5 attainment areas 
set forth in the Seitz memo, the 2005 PM2.5 NNSR Guidance 
recommended that until EPA promulgated the PM2.5 major NSR 
regulations, ``States should use a PM10 nonattainment major 
NSR program as a surrogate to address the requirements of nonattainment 
major NSR for the PM2.5 NAAQS.''
    In the NSR PM2.5 Rule, EPA required that major 
stationary sources seeking permits must begin directly satisfying the 
PM2.5 requirements, as of the effective date of the rule, 
rather than relying on PM10 as a surrogate, with two 
exceptions. The first exception is the ``grandfathering'' provision in 
the federal PSD program at 40 CFR 52.21(i)(1)(xi). This grandfathering 
provision applied to sources that had applied for, but had not yet 
received, a final and effective PSD permit before the July 15, 2008, 
effective date of the May 16, 2008, final rule. The second exception 
was that states with SIP-approved PSD programs could continue to 
implement the Seitz Memo's PM10 Surrogate Policy for up to 
three years (until May 2011) or until EPA approved the individual 
revised state PSD programs for PM2.5, whichever came first. 
See 73 FR 28321.\4\
---------------------------------------------------------------------------

    \4\ Additional information on this issue can also be found in an 
August 12, 2009, final order on a title V petition describing the 
use of PM10 as a surrogate for PM2.5. In the 
Matter of Louisville Gas & Electric Company, Petition No. IV-2008-3, 
Order on Petition (August 12, 2009).
---------------------------------------------------------------------------

    On February 11, 2010, EPA proposed to repeal the grandfathering 
provision for PM2.5 contained in the federal PSD program at 
40 CFR 52.21(i)(1)(xi) and to end early the PM10 Surrogate 
Policy applicable in states that have a SIP-approved PSD program. See 
75 FR 6827. In support of this proposal, EPA explained that the 
PM2.5 implementation issues that led to the adoption of the 
PM10 Surrogate Policy in 1997 have been largely resolved to 
a degree sufficient for sources and permitting authorities to conduct 
meaningful permit-related PM2.5 analyses.
    On May 18, 2011 (76 FR 28646), EPA took final action to repeal the 
PM2.5 grandfathering provision at 40 CFR 52.21(i)(1)(xi). 
This final action ended the use of the 1997 PM10 Surrogate 
Policy for PSD permits under the federal PSD program at 40 CFR 52.21. 
In effect, any PSD permit applicant previously covered by the 
grandfathering provision (for sources that completed and submitted a 
permit application before July 15, 2008) \5\ that did not have a final 
and effective PSD permit before the effective date of the repeal would 
no longer be able to rely on the 1997 PM10 Surrogate Policy 
to satisfy the PSD requirements for PM2.5 unless the 
application included a valid surrogacy demonstration. See 76 FR 28646. 
Mississippi's May 12, 2011, SIP revision, did not IBR the 
grandfathering provision at 40 CFR 52.21(i)(1)(xi), in accordance with 
the repeal of the PM2.5 grandfathering provision.
---------------------------------------------------------------------------

    \5\ Sources that applied for a PSD permit under the federal PSD 
program on or after July 15, 2008, are already excluded from using 
the 1997 PM10 Surrogate Policy as a means of satisfying 
the PSD requirements for PM2.5. See 76 FR 28321.
---------------------------------------------------------------------------

2. ``Condensable'' Provision
    In the NSR PM2.5 Rule, EPA revised the definition of 
``regulated NSR

[[Page 43035]]

pollutant'' for PSD to add a paragraph providing that ``particulate 
matter (PM) emissions, PM2.5 emissions and PM10 
emissions'' shall include gaseous emissions from a source or activity 
which condense to form particulate matter at ambient temperatures and 
that on or after January 1, 2011, such condensable particulate matter 
shall be accounted for in applicability determinations and in 
establishing emissions limitations for PM, PM2.5 and 
PM10 in permits. See 40 CFR 51.166(b)(49)(vi), 
52.21(b)(50)(vi) and ``Emissions Offset Interpretative Ruling'' (40 CFR 
part 51, appendix S). A similar paragraph added to the NNSR rule does 
not include ``particulate matter (PM) emissions.'' See 40 CFR 
51.165(a)(1)(xxxvii)(D).
    On March 16, 2012, EPA proposed a rulemaking to amend the 
definition of ``regulated NSR pollutant'' promulgated in the 2008 NSR 
PM2.5 Rule regarding the PM condensable provision at 40 CFR 
51.166(b)(49)(vi), 52.21(b)(50)(i) and EPA's Emissions Offset 
Interpretative Ruling. See 77 FR 15656. The rulemaking proposes to 
remove the inadvertent requirement in the NSR PM2.5 Rule 
that the measurement of condensable ``particulate matter emissions'' be 
included as part of the measurement and regulation of ``particulate 
matter emissions.'' The term ``particulate matter emissions'' includes 
particles that are larger than PM2.5 and PM10 and 
is an indicator measured under various New Source Performance Standards 
(NSPS) (40 CFR part 60).\6\ Mississippi's May 12, 2011, SIP revision 
IBR EPA's definition for regulated NSR pollutant for condensables (at 
APC-S-5) including the term ``particulate matter emissions,'' as 
promulgated in the NSR PM2.5 Rule. EPA's review of 
Mississippi's May 12, 2011, SIP revision with regard to the NSR 
PM2.5 Rule condensable provision is provided below in 
Section IV.
---------------------------------------------------------------------------

    \6\ In addition to the NSPS for PM, states have regulated 
``particulate matter emissions'' for many years in their SIPs for 
PM, and the same indicator has been used as a surrogate for 
determining compliance with certain standards contained in 40 CFR 
part 63, regarding National Emission Standards for Hazardous Air 
Pollutants.
---------------------------------------------------------------------------

3. NOX Insignificance Determination
    Fine particles can be emitted directly from a facility or formed 
secondarily in the atmosphere from emissions of other compounds 
referred to as precursors. In addition to direct PM2.5 
emissions, pollutants that can contribute to ambient PM2.5 
concentrations (known as ``precursors'') include SO2, 
NOX, volatile organic compounds (VOC) and ammonia (of which 
all undergo chemical reactions to form secondary PM). In most areas of 
the country, PM2.5 precursor emissions are major 
contributors to ambient PM2.5 concentrations. The relative 
contribution to ambient PM2.5 concentrations from each of 
these pollutants varies by area. The relative effect of reducing 
emissions of these pollutants is also highly variable. In the NSR 
PM2.5 Rule, EPA established various approaches for 
addressing the individual precursors to PM2.5 under the 
CAA's NSR provisions. See 73 FR 28321.
    Based on scientific factors suggesting that nitrate concentrations 
vary significantly across the country, EPA established a ``presumed-
in'' approach for NOX as a PM2.5 precursor. This 
approach is warranted based on the well-known transformation of 
NOX into nitrates, coupled with the fact that nitrate 
concentrations vary significantly around the country. The final NSR 
PM2.5 Rule requires that states treat NOX as a 
PM2.5 precursor in all areas unless the state demonstrates 
to the Administrator's satisfaction or EPA demonstrates that emissions 
of NOX from sources in a specific area are not a significant 
contributor to that area's ambient PM2.5 concentrations.\7\ 
See 40 CFR 51.166(b)(49)(i), 51.165(a)(1)(xxxvii) and 52.21(b)(50(i). 
If EPA makes such a demonstration, or a state makes such a 
demonstration and it is approved by EPA, NOX would not be 
considered a PM2.5 precursor under the NSR program in that 
area. If a State or EPA does not make such a demonstration, 
NOX must be regulated as a precursor under the PSD, NNSR, 
and minor source programs for PM2.5.
---------------------------------------------------------------------------

    \7\ The NSR PM2.5 Rule presumes that VOC and ammonia 
are not precursors to PM2.5 unless a state or EPA 
demonstrates that these pollutants are significantly contributing to 
the ambient PM2.5 concentrations in a specific area. The 
rule requires that SO2 be treated as a precursor to 
PM2.5 in all areas.
---------------------------------------------------------------------------

    Mississippi's May 12, 2011, SIP revision IBR the provision that 
NOX is presumed to be a precursor for PM2.5. 
However, MDEQ also submitted to EPA a NOX insignificance 
demonstration to show that NOX emissions in the state of 
Mississippi are not contributing to ambient PM2.5 
concentrations in the state. At this time, EPA is still considering 
Mississippi's NOX insignificance demonstration and will take 
action on this portion of the May 12, 2011, SIP revision in a separate 
rulemaking. However, until EPA takes action on Mississippi's 
insignificance demonstration, EPA is proposing to approve Mississippi's 
incorporation into its SIP the federal regulatory provision providing 
that NOX is a presumed PM2.5 precursor.

B. PM2.5 PSD Increment-SILs-SMC Rule

    As mentioned above, EPA finalized the PM2.5 PSD 
Increment-SILs-SMC Rule to provide additional regulatory requirements 
under the PSD program regarding the implementation of the 
PM2.5 NAAQS for NSR.\8\ Specifically, the rule establishes 
the following to implement the PM2.5 NAAQS for the PSD 
program: (1) PM2.5 increments pursuant to section 166(a) of 
the CAA to prevent significant deterioration of air quality in areas 
meeting the NAAQS; (2) SILs used as a screening tool (by a major source 
subject to PSD) to evaluate the impact a proposed major source or 
modification may have on the NAAQS or PSD increment; and (3) a SMC, 
(also a screening tool) used by a major source subject to PSD to 
determine the subsequent level of data gathering required for a PSD 
permit application for emissions of PM2.5. As part of the 
response to comments on October 20, 2010 final rulemaking, EPA 
explained that, the agency agrees that the SILs and SMCs used as de 
minimis thresholds for the various pollutants are useful tools that 
enable permitting authorities and PSD applicants to screen out 
``insignificant'' activities; however, the fact remains that these 
values are not required by the Act as part of an approvable SIP 
program. EPA believes that most states are likely to adopt the SILs and 
SMCs because of the useful purpose they serve regardless of our 
position that the values are not mandatory. Alternatively, states may 
develop more stringent values if they desire to do so. In any case, 
states are not under any SIP-related deadline for revising their PSD 
programs to add these screening tools. See 75 FR 64864, 64900.
---------------------------------------------------------------------------

    \8\ EPA proposed approval of the PSD Increments-SILs-SMC Rule on 
September 21, 2007. See 72 FR 54112.
---------------------------------------------------------------------------

    Mississippi's May 12, 2011, SIP revision IBR the NSR changes 
promulgated in the PM2.5 PSD Increment-SILs-SMC Rule to be 
consistent with the federal NSR regulations and to appropriately 
implement the State's NSR program for the PM2.5 NAAQS. More 
detail on the PM2.5 PSD Increment-SILs-SMC Rule can be found 
in EPA's October 20, 2010, final rule and is summarized below. See 75 
FR 64864. EPA is not proposing to take action to approve the SILs 
(promulgated in the PM2.5 PSD Increment-SILs-SMC Rule) into 
the Mississippi SIP in this rulemaking. EPA's authority to implement 
the SILs

[[Page 43036]]

and SMC for PSD purposes has been challenged by the Sierra Club. Sierra 
Club v. EPA, Case No 10-1413 (D.C. Circuit Court).\9\ More details 
regarding Mississippi's changes to its NSR regulations are also 
summarized below in Section IV.
---------------------------------------------------------------------------

    \9\ On April 6, 2012, EPA filed a brief with the D.C. Circuit 
court defending the Agency's authority to implement SILs and SMC for 
PSD purposes.
---------------------------------------------------------------------------

1. What are PSD increments?
    As established in part C of title I of the CAA, EPA's PSD program 
protects public health from adverse effects of air pollution by 
ensuring that construction of new or modified sources in attainment or 
unclassifiable areas does not lead to significant deterioration of air 
quality while simultaneously ensuring that economic growth will occur 
in a manner consistent with preservation of clean air resources. Under 
section 165(a)(3) of the CAA, a PSD permit applicant must demonstrate 
that emissions from the proposed construction and operation of a 
facility ``will not cause, or contribute to, air pollution in excess of 
any maximum allowable increase or allowable concentration for any 
pollutant.'' In other words, when a source applies for a permit to emit 
a regulated pollutant in an area that meets the NAAQS, the state and 
EPA must determine if emissions of the regulated pollutant from the 
source will cause significant deterioration in air quality. Significant 
deterioration occurs when the amount of the new pollution exceeds the 
applicable PSD increment, which is the ``maximum allowable increase'' 
of an air pollutant allowed to occur above the applicable baseline 
concentration \10\ for that pollutant. PSD increments prevent air 
quality in clean areas from deteriorating to the level set by the 
NAAQS. Therefore an increment is the mechanism used to estimate 
``significant deterioration'' of air quality for a pollutant in an 
area.
---------------------------------------------------------------------------

    \10\ Section 169(4) of the CAA provides that the baseline 
concentration of a pollutant for a particular baseline area is 
generally the air quality at the time of the first application for a 
PSD permit in the area.
---------------------------------------------------------------------------

    For PSD baseline purposes, a baseline area for a particular 
pollutant emitted from a source includes the attainment or 
unclassifiable area in which the source is located as well as any other 
attainment or unclassifiable area in which the source's emissions of 
that pollutant are projected (by air quality modeling) to result in an 
ambient pollutant increase of at least 1 [mu]g/m\3\ (annual average). 
See 40 CFR 52.21(b)(15)(i). Under EPA's existing regulations, the 
establishment of a baseline area for any PSD increment results from the 
submission of the first complete PSD permit application and is based on 
the location of the proposed source and its emissions impact on the 
area. Once the baseline area is established, subsequent PSD sources 
locating in that area need to consider that a portion of the available 
increment may have already been consumed by previous emissions 
increases. In general, the submittal date of the first complete PSD 
permit application in a particular area is the operative ``baseline 
date.'' \11\ On or before the date of the first complete PSD 
application, emissions generally are considered to be part of the 
baseline concentration, except for certain emissions from major 
stationary sources. Most emissions increases that occur after the 
baseline date will be counted toward the amount of increment consumed. 
Similarly, emissions decreases after the baseline date restore or 
expand the amount of increment that is available. See 75 FR 64864. As 
described in the PM2.5 PSD Increment-SILs-SMC Rule, pursuant 
to the authority under section 166(a) of the CAA, EPA promulgated 
numerical increments for PM2.5 as a new pollutant \12\ for 
which NAAQS were established after August 7, 1977,\13\ and derived 24-
hour and annual PM2.5 increments for the three area 
classifications (Class I, II and III) using the ``contingent safe 
harbor'' approach. See 75 FR 64864 at 64869 and table at 40 CFR 
51.166(c)(1).
---------------------------------------------------------------------------

    \11\ Baseline dates are pollutant specific. That is, a complete 
PSD application establishes the baseline date only for those 
regulated NSR pollutants that are projected to be emitted in 
significant amounts (as defined in the regulations) by the 
applicant's new source or modification. Thus, an area may have 
different baseline dates for different pollutants.
    \12\ EPA generally characterized the PM2.5 NAAQS as a 
NAAQS for a new indicator of PM. EPA did not replace the 
PM10 NAAQs with the NAAQS for PM2.5 when the 
PM2.5 NAAQS were promulgated in 1997. EPA rather retained 
the annual and 24-hour NAAQS for PM2.5 as if 
PM2.5 was a new pollutant even though EPA had already 
developed air quality criteria for PM generally. See 75 FR 64864 
(October 20, 2012).
    \13\ EPA interprets 166(a) to authorize EPA to promulgate 
pollutant-specific PSD regulations meeting the requirements of 
section 166(c) and 166(d) for any pollutant for which EPA 
promulgates a NAAQS after 1977.
---------------------------------------------------------------------------

    In addition to PSD increments for the PM2.5 NAAQS, the 
PM2.5 PSD Increment-SILs-SMC Rule amended the definition at 
40 CFR 51.166 and 52.21 for ``major source baseline date'' and ``minor 
source baseline date'' (including trigger dates) to establish the 
PM2.5 NAAQS specific dates associated with the 
implementation of PM2.5 PSD increments. See 75 FR 64864. In 
accordance with section 166(b) of the CAA, EPA required the states to 
submit revised implementation plans to EPA for approval (to adopt the 
PM2.5 PSD increments) within 21 months from promulgation of 
the final rule (by July 20, 2012). Each state was responsible for 
determining how increment consumption and the setting of the minor 
source baseline date for PM2.5 would occur under its own PSD 
program. Regardless of when a State begins to require PM2.5 
increment analysis and how it chooses to set the PM2.5 minor 
source baseline date, the emissions from sources subject to PSD for 
PM2.5 for which construction commenced after October 20, 
2010 (major source baseline date) consume PM2.5 increment 
and should be included in the increment analyses occurring after the 
minor source baseline date is established for an area under the state's 
revised PSD program. As discussed in detail in Section IV, 
Mississippi's May 12, 2011, SIP revision IBR the PM2.5 
increment permitting requirements promulgated in the PM2.5 
PSD Increment-SILs-SMC Rule.
2. What are significant monitoring concentrations?
    Under the CAA and EPA regulations, an applicant for a PSD permit is 
required to gather preconstruction monitoring data in certain 
circumstances. Section 165(a)(7) calls for ``such monitoring as may be 
necessary to determine the effect which emissions from any such 
facility may have, or is having, on air quality in any areas which may 
be affected by emissions from such source.'' In addition, section 
165(e) requires an analysis of the air quality in areas affected by a 
proposed major facility or major modification and calls for gathering 
one year of monitoring data unless the reviewing authority determines 
that a complete and adequate analysis may be accomplished in a shorter 
period. These requirements are codified in EPA's PSD regulations at 40 
CFR 51.166(m) and 40 CFR 52.21(m). In accordance with EPA's Guideline 
for Air Quality Modeling (40 CFR part 51, appendix W), the 
preconstruction monitoring data is primarily used to determine 
background concentrations in modeling conducted to demonstrate that the 
proposed source or modification will not cause or contribute to a 
violation of the NAAQS. See 40 CFR part 51, appendix W, section 9.2. 
SMC are numerical values that represent thresholds of insignificant 
(i.e., de minimis \14\), monitored (ambient)

[[Page 43037]]

impacts on pollutant concentrations. In EPA's PM2.5 PSD 
Increment-SILs-SMC Rule, EPA established a SMC of 4 [micro]g/m\3\ for 
PM2.5 to be used as a screening tool by a major source 
subject to PSD to determine the subsequent level of data gathering 
required for a PSD permit application for emissions of 
PM2.5. See 75 FR 64864.
---------------------------------------------------------------------------

    \14\ The de minimis principle is grounded in the decision 
described by the court case Alabama Power Co. v. Costle, 636 F.2d 
323, 360 (D.C. Cir. 1980). In this case reviewing EPA's 1978 PSD 
regulations, the court recognized that ``there is likely a basis for 
an implication of de minimis authority to provide exemption when the 
burdens of regulation yield a gain of trivial or no value.'' 636 
F.2d at 360.
---------------------------------------------------------------------------

    Using the SMC as a screening tool, sources may be able to 
demonstrate that the modeled air quality impact of emissions from the 
new source or modification, or the existing air quality level in the 
area where the source would construct, is less than the SMC (i.e., de 
minimis), and as such, may be allowed to forego the preconstruction 
monitoring requirement for a particular pollutant at the discretion of 
the reviewing authority. See 40 CFR 51.166(i)(5) and 52.21(i)(5). SMCs 
are not minimum required elements of an approvable SIP under the CAA. 
This de minimis value is widely considered to be a useful component for 
implementing the PSD program, but is not absolutely necessary for the 
states to implement PSD programs. States can satisfy the statutory 
requirements for a PSD program by requiring each PSD applicant to 
submit air quality monitoring data for PM2.5 without using 
de minimis thresholds to exempt certain sources from such requirements. 
See 75 FR 64864. The SMC became effective under the federal PSD program 
on December 20, 2010. States with EPA-approved PSD programs that adopt 
the SMC for PM2.5, however, may use the SMC, once it is part 
of an approved SIP, to determine when it may be appropriate to exempt a 
particular major stationary source or major modification from the 
monitoring requirements under its state PSD program. Mississippi's May 
12, 2011, revision IBR the SMC provision into the Mississippi SIP.
    Recently, the Sierra Club filed suit challenging EPA's authority to 
implement the PM2.5 SILs \15\ as well as the SMC for PSD 
purposes as promulgated in the October 20, 2012, rule. Sierra Club v. 
EPA, Case No 10-1413, D.C. Circuit Court. Specifically regarding the 
SMC, Sierra Club claims that the use of SMCs to exempt a source from 
submitting a year's worth of monitoring data is inconsistent with the 
CAA. EPA responded to Sierra Club's claims in a Brief dated April 6, 
2012, which describes the Agency's authority to develop and promulgate 
SMC.\16\ A copy of EPA's April 6, 2010 Brief can be found in the docket 
for today's rulemaking at www.regulations.gov using docket ID: EPA-R04-
OAR-2012-0081.
---------------------------------------------------------------------------

    \15\ As mentioned earlier, due to litigation by the Sierra Club, 
EPA is not proposing to take action on the SILs portion of the 
Mississippi May 12, 2011 SIP revision at this time but will take 
action once the court case regarding SILs implementation is 
resolved.
    \16\ Additional information on this issue can also be found in 
an April 25, 2010 comment letter from EPA Region 6 to the Louisiana 
Department of Environmental Quality regarding the SILs-SMC 
litigation. A copy of this letter can be found in the docket for 
today's rulemaking at www.regulations.gov using docket ID: EPA-R04-
OAR-2012-0081.
---------------------------------------------------------------------------

IV. What is EPA's analysis of Mississippi's SIP revision?

    Mississippi currently has a SIP-approved NSR program for new and 
modified stationary sources. MDEQ's PSD preconstruction rules are found 
at rule APC-S-5--Regulation for the Prevention of Significant 
Deterioration of Air Quality and apply to major stationary sources or 
modifications constructed in areas designated attainment or 
unclassifiable/attainment as required under part C of title I the CAA 
with respect to the NAAQS. Mississippi's regulation APC-S-5 IBR the 
federal NSR PSD regulations at 40 CFR 51.166 and 52.21 into the 
Mississippi SIP. In effect, MDEQ's May 12, 2011, SIP revision updates 
the State's IBR date for APC-S-5 to March 22, 2011, to include PSD 
permitting regulations promulgated in the NSR PM2.5 Rule and 
the PM2.5 PSD Increment-SILs-SMC Rule into the Mississippi 
SIP. These changes to Mississippi's regulation APC-S-5 became state 
effective on June 2, 2011. EPA is proposing to approve changes to 
Mississippi's rules at APC-S-5 to update the State's existing SIP-
approved PSD program to be consistent with federal NSR regulations, (at 
40 CFR 51.166 and 52.21) and the CAA.

A. NSR PM2.5 Implementation Rule

    Mississippi's May 12, 2011, SIP revision establishes that the 
State's existing NSR permitting program requirements for PSD apply to 
the PM2.5 NAAQS and its precursors. Specifically, the SIP 
revision IBR the following NSR PM2.5 Rule provisions into 
the Mississippi SIP at regulation APC-S-5: (1) The requirement for NSR 
permits to address directly emitted PM2.5 and precursor 
pollutants; (2) significant emission rates for direct PM2.5 
and precursor pollutants (SO2 and NOX); and (3) 
the requirement that condensable PM be addressed in enforceable 
PM10 and PM2.5 emission limits included in PSD 
permits.
    As mentioned above, Mississippi's May 12, 2011, SIP revision IBR 
into the State's PSD program at APC-S-5 the requirement to address 
condensable PM in applicability determinations and in establishing 
enforceable emission limits in PSD and NNSR permits, as established in 
the NSR PM2.5 Rule. As discussed in Section III.A.2, under a 
separate action, EPA has proposed to correct the inadvertent inclusion 
of ``particulate matter emissions'' in the definition of ``regulated 
NSR pollutant'' as an indicator for which condensable emissions must be 
addressed. See 77 FR 75656 (March 16, 2012). Further, on June 26, 2012, 
the State of Mississippi provided a letter to EPA with clarification of 
the State's intent in light of EPA's March 12, 2012, proposed 
rulemaking. A copy of this letter can be found in the docket for 
today's rulemaking at www.regulations.gov using docket ID: EPA-R04-OAR-
2012-0081. Specifically, Mississippi requested that EPA not approve the 
term ``particulate matter emissions'' (at APC-S-5) as part of the 
definition for ``regulated NSR pollutant'' regarding the inclusion of 
condensable emissions in applicability determinations and in 
establishing emissions limitations for PM. Therefore, given the State's 
request and EPA's intention to amend the definition of ``regulated NSR 
pollutant,'' EPA is not proposing action to approve the terminology 
``particulate matter emissions'' into the Mississippi SIP for the 
condensable provision in the definition of ``regulated NSR pollutant.'' 
EPA is, however, proposing to approve into the Mississippi SIP at APC-
S-5 the remaining condensable requirement at 40 CFR 51.166(b)(49)(vi), 
which requires that condensable emissions be accounted for in 
applicability determinations and in establishing emissions limitations 
for PM2.5 and PM10. Regarding the grandfathering 
provision, MDEQ's May 12, 2012 SIP revision included new language at 
APC-S-5(2.7) that excluded the provision for PM2.5 (at 40 
CFR 52.21(i)(1)(xi)) from the PSD program regulations in accordance 
with the repeal of the PM2.5 grandfathering provision.
    EPA's NSR PM2.5 Rule identifies NOX as a 
presumed PM2.5 precursor in all attainment and 
unclassifiable areas unless the state demonstrates to the 
Administrator's satisfaction or EPA demonstrates that emissions of 
NOX from sources in a specific area are not a significant 
contributor to that area's ambient PM2.5 concentrations. 
Mississippi's May 12, 2011, SIP submittal included a technical

[[Page 43038]]

demonstration proposing that NOX sources in Mississippi do 
not significantly contribute to PM2.5 ambient air 
concentrations in the state. As stated in Mississippi's May 12, 2011, 
SIP revision, NOX will be considered as a precursor to 
PM2.5 in Mississippi until such time as EPA takes action on 
the state's technical NOX insignificance demonstration or 
upon plan disapproval. Currently, EPA is considering Mississippi's 
NOX insignificance demonstration and will take action on 
this portion of the May 12, 2011, SIP submission in a separate 
rulemaking. Therefore, as part of MDEQ's May 12, 2011, revision to IBR 
the federal regulations at 40 CFR 51.166 and 52.21, EPA is proposing at 
this time to approve into the Mississippi SIP that NOX is a 
presumed PM2.5 precursor. Lastly, Mississippi's May 12, 
2011, SIP revision also requests that EPA remove from the SIP the 
exclusion language at APC-S-5(2.7) regarding the NSR PM2.5 
Rule provisions. In Mississippi's December 9, 2010 Greenhouse Gas 
Tailoring Rule final SIP revision, MDEQ added specific language at APC-
S-5(2.7) excluding from the IBR of 40 CFR 52.21 the PSD NSR 
PM2.5 Rule provisions promulgated in the May 16, 2008 rule 
and stated they would submit a separate rulemaking to address those PSD 
requirements. Mississippi's May 12, 2011, SIP submittal, the subject of 
today's proposed rulemaking, addresses the PSD NSR PM2.5 
Rule provisions that were excluded at APC-S-5(2.7). Therefore the 
exclusion language for the NSR PM2.5 Rule provisions at APC-
S-5(2.7) is no longer necessary and EPA is today proposing to remove it 
from the Mississippi SIP. EPA is proposing to approve the NSR 
PM2.5 requirements mentioned above into the Mississippi SIP 
because EPA has made the preliminary determination that this change is 
consistent with federal regulations promulgated in the NSR 
PM2.5 Rule and section 110 of the CAA.

B. PM2.5 PSD Increment-SILs-SMC Rule

    MDEQ's May 12, 2011, SIP revision IBR the following provisions into 
the Mississippi SIP at regulation APC-S-5 as promulgated in the October 
20, 2010, PM2.5 PSD Increment-SILs-SMC Rule: (1) PSD 
increments for PM2.5 annual and 24-hour NAAQS pursuant to 
section 166(a) of the CAA; (2) SILs used as a screening tool (used by a 
major source subject to PSD) to evaluate the impact a proposed major 
source or modification may have on the NAAQS or PSD increment; and (3) 
SMC also used as a screening tool to determine the level of data 
gathering required of a major source in support of its PSD permit 
application for PM2.5 emissions.
    Specifically, Mississippi's May 12, 2011, SIP revision IBR into the 
Mississippi SIP (at APC-S-5) the PM2.5 PSD increments 
(established in the tables at 40 CFR 51.166(c)(1) and (p)(4); the 
amendments to the ``major source baseline date'' (at 40 CFR 
51.166(b)(14)(i)(c)) and 52.21(b)(14)(i)(c)); the ``minor source 
baseline date'' and establishment of the ``trigger date'' (40 CFR 
51.166(b)(14)(ii)(c) and 52.21(b)(14)(ii)(c)); and the definition of 
``baseline area'' (at 40 CFR 51.166(b)(15)(i) and (ii) and 
52.21(b)(15)(i) and (ii)). These changes, which are associated with the 
implementation or consumption of the PSD increments for the 
PM2.5 NAAQS, are needed to implement the state's NSR program 
for the PM2.5 NAAQS consistent with the federal NSR 
regulations. Also, Mississippi's SIP revision adds the SMC of 4 
[micro]g/m\3\ for PM2.5 NAAQS to the existing monitoring 
exemption at 40 CFR 51.166(i)(5)(i)(c) and 52.21(i)(5)(i)(c). In 
today's action, EPA is proposing to approve Mississippi's May 12, 2011, 
SIP revision to address PM2.5 PSD increments.
    Regarding the SILs and SMC established in the October 20, 2010, 
PM2.5 PSD Increment-SILs-SMC Rule, the Sierra Club has 
challenged EPA's authority to implement SILs and SMC. In a brief filed 
in the D.C. Circuit on April 6, 2012, EPA described the Agency's 
authority under the CAA to promulgate and implement the SMCs and SILs 
de minimis thresholds. With respect to the SMCs submitted by 
Mississippi in the May 12, 2011, SIP revision, EPA is proposing to 
approve these promulgated thresholds into the Mississippi SIP as EPA 
believes the SMC are a valid exercise of the Agency's de minimis 
authority. Furthermore Mississippi's May 12, 2011, SIP revision is 
consistent with EPA's current promulgated provisions in the October 20, 
2011, rule. However, EPA notes that future Court action may require 
subsequent rule revisions and SIP revisions from Mississippi.
    The May 12, 2012, SIP revision submitted by Mississippi to IBR the 
new PSD requirements for PM2.5 pursuant to the 
PM2.5 PSD Increment-SILs-SMC Rule also includes the new 
regulatory text at 40 CFR 51.166(k)(2) and 52.21(k)(2), concerning the 
implementation of SILs for PM2.5. EPA stated in the preamble 
to the October 20, 2010 final rule that we do not consider the SILs to 
be a mandatory SIP element, but regard them as discretionary on the 
part of regulating authority for use in the PSD permitting process. 
Nevertheless, the PM2.5 SILs are currently the subject of 
litigation before the U.S. Court of Appeals. (Sierra Club v. EPA, Case 
No 10-1413 D.C. Circuit). In response to that litigation, EPA has 
requested that the Court remand and vacate the regulatory text in EPA's 
PSD regulations at paragraph (k)(2) so that EPA can make necessary 
rulemaking revisions to that text. In light of EPA's request for remand 
and vacatur and our acknowledgement of the need to revise the 
regulatory text presently contained at paragraph (k)(2) of sections 
51.166 and 52.21, we do not believe that it is appropriate at this time 
to approve that portion of the State's SIP revision that contains the 
affected regulatory text in the State's PSD regulations, at APC-S-5. 
Instead, we are taking no action at this time with regard to that 
specific provision contained in the SIP revision. EPA will take action 
on the SILs portion of Mississippi's May 12, 2011, SIP revision in a 
separate rulemaking once the issue regarding the court case has been 
resolved.
    The aforementioned amendments to Mississippi's SIP provide the 
framework for implementation of PM2.5 NAAQS in the states 
NSR permitting. Based on review and consideration of Mississippi's May 
12, 2011, SIP revision, EPA has made the preliminary determination to 
approve the aforementioned PSD permitting provisions promulgated in the 
NSR PM2.5 Rule and PM2.5 PSD Increment-SILs-SMC 
Rule into the Mississippi SIP to implement the NSR program for the 
PM2.5 NAAQS.

V. Proposed Action

    EPA is proposing to approve portions of Mississippi's May 12, 2011, 
SIP revision adopting federal regulations amended in the May 16, 2008, 
NSR PM2.5 Rule and the October 20, 2010, PM2.5 
PSD Increment-SILs-SMC rule into the Mississippi SIP with the exception 
of the SIL thresholds and the provision regarding the applicability of 
the term ``particulate matter emissions.'' EPA has made the preliminary 
determination that this SIP revision, with regard to the aforementioned 
proposed actions, is approvable because it is consistent with section 
110 of the CAA and EPA regulations regarding NSR permitting.

VI. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the Act and applicable 
federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions,

[[Page 43039]]

EPA's role is to approve state choices, provided that they meet the 
criteria of the CAA. Accordingly, this proposed action merely approves 
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 F43255, 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 proposed rule 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, Intergovernmental 
relations, Nitrogen oxides, Ozone, Particulate matter, Reporting and 
recordkeeping requirements.

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

    Dated: July 12, 2012.
A. Stanley Meiburg,
Acting Regional Administrator, Region 4.
[FR Doc. 2012-17893 Filed 7-20-12; 8:45 am]
BILLING CODE 6560-50-P