Proposed Rule2025-05927
Air Plan Approval; Louisiana; Interstate Transport Requirements for the 2010 SO2 NAAQS
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
April 9, 2025
Issuing agencies
Environmental Protection Agency
Abstract
Pursuant to the Federal Clean Air Act (CAA or the Act), the Environmental Protection Agency (EPA) is proposing to approve the portion of the State Implementation Plan (SIP) submittal from the State of Louisiana demonstrating that the State satisfies the interstate transport requirements of section 110(a)(2)(D)(i)(I), also known as the "good neighbor" provision of the CAA, for the 2010 1-hour sulfur dioxide (SO<INF>2</INF>) primary National Ambient Air Quality Standard (NAAQS). The good neighbor provision requires each State's implementation plan contain adequate provisions prohibiting the interstate transport of air pollution in amounts that will contribute significantly to nonattainment, or interfere with maintenance, of a NAAQS in any other State.
Full Text
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<title>Federal Register, Volume 90 Issue 67 (Wednesday, April 9, 2025)</title>
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[Federal Register Volume 90, Number 67 (Wednesday, April 9, 2025)]
[Proposed Rules]
[Pages 15213-15218]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-05927]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 90, No. 67 / Wednesday, April 9, 2025 /
Proposed Rules
[[Page 15213]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R06-OAR-2013-0465; FRL-12681-01-Region 6]
Air Plan Approval; Louisiana; Interstate Transport Requirements
for the 2010 SO2 NAAQS
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: Pursuant to the Federal Clean Air Act (CAA or the Act), the
Environmental Protection Agency (EPA) is proposing to approve the
portion of the State Implementation Plan (SIP) submittal from the State
of Louisiana demonstrating that the State satisfies the interstate
transport requirements of section 110(a)(2)(D)(i)(I), also known as the
``good neighbor'' provision of the CAA, for the 2010 1-hour sulfur
dioxide (SO<INF>2</INF>) primary National Ambient Air Quality Standard
(NAAQS). The good neighbor provision requires each State's
implementation plan contain adequate provisions prohibiting the
interstate transport of air pollution in amounts that will contribute
significantly to nonattainment, or interfere with maintenance, of a
NAAQS in any other State.
DATES: Written comments must be received on or before May 9, 2025.
ADDRESSES: Submit your comments, identified by Docket Number EPA-R06-
OAR-2013-0465, at <a href="http://www.regulations.gov">www.regulations.gov</a>. Follow the online instructions
for submitting comments. Once submitted, comments cannot be edited or
removed from <a href="http://Regulations.gov">Regulations.gov</a>. The EPA may publish any comment received
to its public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, please contact Nevine
Salem, (214) 665-7222, <a href="/cdn-cgi/l/email-protection#9ae9fbf6fff7b4f4ffecf3f4ffdaffeafbb4fdf5ec"><span class="__cf_email__" data-cfemail="6615070a030b480803100f08032603160748010910">[email protected]</span></a>. For the full EPA public
comment policy, information about CBI or multimedia submissions, and
general guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
Docket: The index to the docket for this action is available
electronically at <a href="http://www.regulations.gov">www.regulations.gov</a>. While all documents in the
docket are listed in the index, some information may not be publicly
available due to docket file size restrictions or content (e.g., CBI).
FOR FURTHER INFORMATION CONTACT: Nevine Salem, (214) 665-7222,
<a href="/cdn-cgi/l/email-protection#b5c6d4d9d0d89bdbd0c3dcdbd0f5d0c5d49bd2dac3"><span class="__cf_email__" data-cfemail="5724363b323a793932213e39321732273679303821">[email protected]</span></a>. We encourage the public to submit comments via
<a href="https://www.regulations.gov">https://www.regulations.gov</a>. Please call or email the contact listed
above if you need alternative access to material indexed but not
provided in the docket.
SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,''
``us,'' or ``our'' is used, we mean the EPA.
I. Background
A. Infrastructure SIPs
On June 2, 2010, the EPA established a revised primary 1-hour
SO<INF>2</INF> NAAQS with a level of 75 parts per billion (ppb), based
on a 3-year average of the annual 99th percentile of daily maximum 1-
hour average concentrations.\1\ CAA section 110(a)(1) requires all
States to submit, within three years after promulgation of a new or
revised NAAQS, SIP submissions to provide for the implementation,
maintenance, and enforcement of the NAAQS.\2\ The EPA has historically
referred to these SIPs as ``infrastructure SIPs.'' Specifically,
section 110(a)(1) provides the procedural and timing requirements for
SIP submissions. Section 110(a)(2) lists specific elements that all
States must meet related to a newly established or revised NAAQS, such
as requirements for monitoring, basic program requirements, and legal
authority that are designed to assure attainment and maintenance of the
NAAQS.
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\1\ See 75 FR 35520 (June 22, 2010).
\2\ In 2012, the EPA retained the current secondary NAAQS for
SO<INF>2</INF>. Thus, the CAA section 110(a)(1) requirement to
submit an infrastructure SIP for this secondary standard was not
triggered. The secondary SO<INF>2</INF> standard is 500 ppb averaged
over three hours, not to be exceeded more than once per year. See 77
FR 20218 (April 3, 2012).
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Section 110(a)(2)(D)(i)(I) of the CAA requires a State's SIP
include provisions prohibiting any source or other type of emissions
activity in the State from emitting any air pollutant in amounts that
will contribute significantly to nonattainment, or interfere with
maintenance, of the NAAQS in any other State. EPA has long interpreted
this language to enact a ``functional prohibition'' on certain
emissions from upwind States, necessitating the EPA's independent
assessment whether those emissions will occur or have been adequately
controlled in the State where they originate.\3\ The EPA often refers
to these requirements as Prong 1 (significant contribution to
nonattainment of the NAAQS) and Prong 2 (interference with maintenance
of the NAAQS). We are addressing Prongs 1 and 2 in this action. All
other applicable infrastructure SIP requirements of the Louisiana SIP
submission are addressed in separate rulemakings.
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\3\ See Genon Rema LLC v. EPA, 722 F.3d 513, 520-24 (3d Cir.
2013); Appalachian Power Co. v. EPA, 249 F.2d 1032, 1045-47 (D.C.
Cir. 2001); see also 71 FR 25328, 25335 (April 28, 2006) (explaining
that the SIP/FIP process under section 110 and the petitioning
process for direct federal regulation under section 126 provide
independent means of effectuating the same ``functional
prohibition'' found in CAA section 110(a)(2)(D)(i)(I)).
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B. 2010 1-Hour SO2 NAAQS Designations Background
In this proposed action, the EPA has considered information from
the 2010 1-hour SO<INF>2</INF> NAAQS designations process, as discussed
in more detail in section III.C of this notice. For this reason, a
brief summary of the EPA's designations process for the 2010 1-hour
SO<INF>2</INF> NAAQS is included here.\4\
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\4\ While designations may provide useful information for
purposes of analyzing transport, the EPA notes that designations
themselves are not dispositive of whether or not upwind emissions
are impacting areas in downwind states. The EPA has consistently
taken the position that CAA section 110(a)(2)(D)(i)(I) requires
elimination of significant contribution and interference with
maintenance in other states, and this analysis is not limited to
designated nonattainment areas. Nor must designations for
nonattainment areas have first occurred before states or the EPA can
act under section 110(a)(2)(D)(i)(I). See, e.g., Clean Air
Interstate Rule, 70 FR 25162, 25265 (May 12, 2005); Cross State Air
Pollution Rule, 76 FR 48208, 48211 (Aug. 8, 2011); Final Response to
Petition from New Jersey Regarding SO<INF>2</INF> Emissions From the
Portland Generating Station, 76 FR 69052 (Nov. 7, 2011) (finding
facility in violation of the prohibitions of CAA section
110(a)(2)(D)(i)(I) with respect to the 2010 1-hour SO<INF>2</INF>
NAAQS prior to issuance of designations for that standard).
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[[Page 15214]]
After the promulgation of a new or revised NAAQS, the EPA is
required to designate areas as ``nonattainment,'' ``attainment,'' or
``unclassifiable'' pursuant to CAA section 107(d)(1)-(2). The process
for designating areas following promulgation of a new or revised NAAQS
is contained in CAA section 107(d). The EPA promulgated the 2010 1-hour
SO<INF>2</INF> NAAQS on June 2, 2010. See 75 FR 35520 (June 22, 2010).
The EPA Administrator signed the first round \5\ of designations; Round
1 \6\ for the 2010 1-hour SO<INF>2</INF> NAAQS on July 25, 2013,
designating 29 areas in 16 States as nonattainment for the 2010 1-hour
SO<INF>2</INF> NAAQS. See 78 FR 47191 (August 5, 2013). The Federal
Register notices for Round 2 designations \7\ published on July 12,
2016 (81 FR 45039) and on December 13, 2016 (81 FR 89870). Round 3
designations \8\ were published on January 9, 2018 (83 FR 1098) and
April 5, 2018 (83 FR 14597). Round 4 designations \9\ were published on
March 26, 2021 (86 FR 16055) \10\ and April 14, 2021 (86 FR 19576).\11\
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\5\ The term ``round'' in this instance refers to which ``round
of designations.''
\6\ EPA and state documents and public comments related to the
Round 1 final designations are in the docket at regulations.gov with
Docket ID No. EPA-HQ-OAR-2012-0233 and at EPA's website for
SO<INF>2</INF> designations at <a href="https://www.epa.gov/sulfur-dioxide-designations">https://www.epa.gov/sulfur-dioxide-designations</a>.
\7\ EPA and state documents and public comments related to the
Round 2 final designations are in the docket at regulations.gov with
Docket ID No. EPA-HQ-OAR-2014-0464 and at EPA's website for
SO<INF>2</INF> designations at <a href="https://www.epa.gov/sulfur-dioxide-designations">https://www.epa.gov/sulfur-dioxide-designations</a>.
\8\ EPA and state documents and public comments related to Round
3 final designations are in the docket at regulations.gov with
Docket ID No. EPA-HQ-OAR-2017-0003 and at EPA's website for
SO<INF>2</INF> designations at <a href="https://www.epa.gov/sulfur-dioxide-designations">https://www.epa.gov/sulfur-dioxide-designations</a>.
\9\ EPA and state documents and public comments related to Round
4 final designations are in the docket at regulations.gov with
Docket ID No. EPA-HQ-OAR-2020-0037 and at EPA's website for
SO<INF>2</INF> designations at <a href="https://www.epa.gov/sulfur-dioxide-designations">https://www.epa.gov/sulfur-dioxide-designations</a>.
\10\ The Round 4 2010 1-hour SO<INF>2</INF> NAAQS designations
action was signed by former EPA Administrator Andrew Wheeler on
December 21, 2020, pursuant to a court-ordered deadline of December
31, 2020. For administrative purposes only, and in compliance with
requirements of the Office of the Federal Register, former Acting
Administrator Jane Nishida re-signed the same action on March 10,
2021, for publication in the Federal Register.
\11\ On August 21, 2015 (80 FR 51052), EPA separately
promulgated air quality characterization requirements for the 2010
1-hour SO<INF>2</INF> NAAQS in the Data Requirements Rule (DRR). The
DRR requires state air agencies to characterize air quality, through
air dispersion modeling or monitoring, in areas associated with
sources that emitted in 2014 2,000 tons per year (tpy) or more of
SO<INF>2</INF>, or that have otherwise been listed under the DRR by
EPA or state air agencies. In lieu of modeling or monitoring, state
air agencies, by specified dates, could elect to impose federally
enforceable emissions limitations on those sources restricting their
annual SO<INF>2</INF> emissions to less than 2,000 tpy, or provide
documentation that the sources have been shut down. EPA used the
information generated by implementation of the DRR to help inform
Round 4 designations for the 2010 1-hour SO<INF>2</INF> NAAQS.
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For Louisiana, the EPA designated St. Bernard Parish area as
nonattainment during the initial round of SO<INF>2</INF> designations
\12\ effective October 4, 2013 based on available monitoring data. The
agency published the Data Requirements Rule (DRR) on August 21, 2015
(80 FR 51052) to provide expectations for collection of data, either
monitoring or modeling, for the remaining designations. In the DRR, the
EPA identified 16 sources in Louisiana which the State was required to
characterize air quality through modeling or monitoring or impose
federally enforceable controls. In Round 2 designations, EPA designated
De Soto Parish as attainment/unclassifiable and Calcasieu Parish as
unclassifiable effective August 12, 2016.\13\ In Round 3 designations,
the EPA designated Pointe Coupee Parish, and Rapides Parish as
attainment/unclassifiable; St. Mary Parish as unclassifiable; and
Evangeline Parish as nonattainment effective April 9, 2018.\14\ Also,
during Round 3, the EPA designated the remaining areas without DRR
sources as attainment/unclassifiable effective April 9, 2018. In Round
4, the EPA designated the remaining Parishes--East Baton Rouge, St.
Charles, St. James, and West Baton Rouge--as attainment/unclassifiable,
completing the area designations for the 2010 1-hour SO<INF>2</INF>
NAAQS in Louisiana effective April 30, 2021.
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\12\ See 78 FR 47191 (August 5, 2013).
\13\ See 81 FR 45039 (July 12, 2016).
\14\ See 83 FR 1089 (January 9, 2018).
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II. Relevant Factors Used To Evaluate 2010 1-Hour SO2 Interstate
Transport SIPs
Although SO<INF>2</INF> is emitted from a similar universe of point
and nonpoint sources as is directly emitted fine particulate matter
(PM<INF>2.5</INF>) and the precursors to ozone and PM<INF>2.5</INF>,
interstate transport of SO<INF>2</INF> is unlike the transport of
PM<INF>2.5</INF> or ozone, which disperse over a wide area and can
contribute to nonattainment or maintenance issues hundreds of miles
from precursor-emitting sources or activities. SO<INF>2</INF> emissions
usually do not undergo long-range transport in the atmosphere. The
transport of SO<INF>2</INF> relative to the 2010 1-hour SO<INF>2</INF>
NAAQS is more analogous to the transport of lead (Pb) relative to the
Pb NAAQS in that emissions of SO<INF>2</INF> typically result in 1-hour
pollutant impacts of greatest concern near the emissions source.
However, ambient 1-hour concentrations of SO<INF>2</INF> do not
decrease as quickly with distance from the source as do 3-month average
concentrations of Pb, because SO<INF>2</INF> gas is not removed by
deposition as rapidly as are Pb particles. Emitted SO<INF>2</INF> has
wider-ranging impacts than emitted Pb, but it does not have such wide-
ranging (far downwind) impacts that treatment in a manner similar to
ozone or PM<INF>2.5</INF> would be appropriate. Accordingly, the
approaches that the EPA has adopted for ozone or PM<INF>2.5</INF>
transport are too regionally focused, and the approach for Pb transport
is too tightly circumscribed to the source, to be appropriate for
assessing SO<INF>2</INF> transport. SO<INF>2</INF> transport is
therefore a unique case and necessitates an approach that lies between
these other approaches to assessing pollutant transport.
In this proposed rulemaking, and consistent with prior
SO<INF>2</INF> transport analyses, the EPA focused on a 50 kilometer
(km)-wide zone around sources of interest because the physical
properties of SO<INF>2</INF> result in relatively localized pollutant
impacts near an emission source that drop off with distance. Given the
properties of SO<INF>2</INF>, the EPA believes that significant impacts
in a downwind State are unlikely at distances greater than 50 km from a
source and thus, we are focusing our review on areas within 50 km of
the State lines. This scale of analysis is consistent with the ``urban
scale'' which is the largest appropriate spatial scale for
SO<INF>2</INF> monitors and is useful for assessing SO<INF>2</INF>
transport and trends in area-wide air quality.\15\
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\15\ For the definition of spatial scales for SO<INF>2</INF>,
see 40 CFR part 58, appendix D, section 4.4 (``Sulfur Dioxide
(SO<INF>2</INF>) Design Criteria''). For further discussion on how
the EPA applies these definitions with respect to interstate
transport of SO<INF>2</INF>, see the EPA's proposed rulemaking on
Connecticut's SO<INF>2</INF> transport SIP. See 82 FR 21351, 21352,
21354 (May 8, 2017).
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As discussed in section III, and in further detail in the Technical
Support Document (TSD) for this action, the EPA reviewed Louisiana's
SO<INF>2</INF> SIP submittal. The State's submission did not have
sufficient information to fully assess whether Louisiana was meeting
its CAA good neighbor requirements for the 2010 SO<INF>2</INF> NAAQS.
Therefore, we elected to
[[Page 15215]]
review and assess other available information regarding SO<INF>2</INF>
emissions and air quality for sources in Louisiana to assist in our own
evaluation. We independently analyzed such information to determine
whether Louisiana meets the interstate transport requirements described
in the CAA.\16\
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\16\ This proposed action is based on the information contained
in the administrative record for this action and does not prejudge
any future EPA action that may make other determinations regarding
the air quality status in Louisiana and downwind states. Any such
future action, such as area designations under any NAAQS, would be
based on separate administrative records and the EPA's analyses of
information that become available at that time. Future available
information may include, monitoring data and modeling analyses
conducted by states, air agencies, and third-party stakeholders.
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Consistent with our prior evaluations of other States'
SO<INF>2</INF> transport obligations, we conducted a weight of evidence
(WOE) analysis evaluating several sources of information, including
current air quality data from monitors as well as available emissions
and/or source modeling for sources in Louisiana and in neighboring
States within 50 km of the Louisiana border. A WOE approach can be
appropriate in instances, such as in this case, to determine whether or
not SO<INF>2</INF> emissions from Louisiana contribute to nonattainment
or maintenance issues in adjoining States. A WOE analysis that is based
strictly on available data may not be sufficient in all instances for
evaluating interstate SO<INF>2</INF> transport, and additional analysis
may be necessary. Further, the term ``WOE'' does not establish the
legal or technical meaning for what constitutes significant
contribution to nonattainment or interference with maintenance for the
2010 SO<INF>2</INF> NAAQS. Rather, the term refers to the gathering and
consideration of a wide range of information, on a case-by-case basis,
to make a determination regarding whether a statutory or regulatory
standard is met.
In other SO<INF>2</INF> transport SIP actions, the EPA has
generally been able to use a WOE analysis of available information to
reach a conclusion that there are no SO<INF>2</INF> nonattainment or
maintenance issues in the relevant areas of other States, or that no
sources in the upwind State are contributing to those issues. If the
available evidence indicated, however, that an upwind source, sources,
or emissions activities were contributing to an out-of-state
SO<INF>2</INF> nonattainment or maintenance problem, then further
analysis and a regulatory determination would be necessary concerning
what amount of those emissions, if any, constituted ``significant
contribution'' under Prong 1 or Prong 2 of the good neighbor provision.
We find that there is sufficient information to allow the EPA to
make a determination that under baseline conditions and likely future
emissions scenarios no Louisiana sources are contributing or will
contribute to any out-of-state SO<INF>2</INF> nonattainment or
maintenance concerns, therefore it is not necessary for purposes of
this action to render a determination concerning what amount of
emissions would be ``significant'' and therefore subject to prohibition
under the good neighbor provision.\17\
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\17\ Cf. Genon Rema v. EPA, 722 F.3d 513 (3d Cir. 2013)
(upholding EPA grant of CAA section 126(b) petition and
establishment of direct federal emissions control requirements on
SO<INF>2</INF> source in Pennsylvania found to be significantly
contributing to nonattainment and interfering with maintenance of
the 2010 SO<INF>2</INF> NAAQS in New Jersey).
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III. Louisiana's SIP Submission and EPA's Analysis
A. State Submission
On June 4, 2013, Louisiana submitted to the EPA a SIP revision to
address the requirements of CAA section 110(a)(1) and (2), including
section 110(a)(2)(D)(i)(I) for the 2010 SO<INF>2</INF> NAAQS. The
submittal cited Louisiana's approved Clean Air Interstate Rule SIP
revision as verification that the State met and would continue to meet
the requirements of 110(a)(2)(D)(i)(I) for the 2010 SO<INF>2</INF>
NAAQS. A copy of the submittal is in the docket for this action. Other
portions of this SIP revision were addressed in 81 FR 68322 (October 4,
2016).
The 2005 Clean Air Interstate Rule \18\ (CAIR) covered 28 eastern
States (including Louisiana) and the District of Columbia. CAIR was
designed to address interstate transport of ozone and fine particulate
matter (PM<INF>2.5</INF>) pollution. CAIR required the covered eastern
States to make reductions in SO<INF>2</INF> and nitrogen oxides
(NO<INF>X</INF>) emissions that significantly contribute to the
nonattainment or interference with the maintenance of the 1997
PM<INF>2.5</INF> and 1997 ozone NAAQS in any downwind State (70 FR
25161, May 12, 2005). CAIR addressed interstate transport for the 1997
PM<INF>2.5</INF> and 1997 ozone NAAQS but did not address interstate
transport for the 2010 SO<INF>2</INF> NAAQS. Subsequently, the D.C.
Circuit invalidated CAIR and required that the rule be revised.\19\ The
court, however, left CAIR in place in order to ``temporarily preserve
the environmental values covered by CAIR'' until the EPA could, by
rulemaking, replace CAIR consistent with the court's opinion.\20\ In
2011, the EPA promulgated the Cross-State Air Pollution Rule (CSAPR) to
replace CAIR.\21\ CSAPR addresses interstate transport for the 1997
PM<INF>2.5</INF>, 1997 ozone and 2006 PM<INF>2.5</INF> NAAQS. CSAPR
replaced CAIR beginning on January 1, 2015.\22\ Neither CAIR nor CSAPR
directly addresses interstate transport for the 2010 SO<INF>2</INF>
NAAQS. Because CAIR is no longer in place (and was only allowed to
remain temporarily in place pending its replacement at the time of
Louisiana's submission, see 76 FR 48208, 48223-24 (Aug. 8, 2011)) and
because it did not address the 2010 SO<INF>2</INF> NAAQS, Louisiana's
sole reliance on CAIR is not adequate on its own to demonstrate the
State meets the requirements of CAA section 110(a)(2)(D)(i)(I).
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\18\ May 12, 2005 (70 FR 25162).
\19\ North Carolina v. EPA, 531 F. 3d 896, 901 (D.C. Cir. 2008),
modified, 550 F. 3d 1176 (D.C. Cir. 2008).
\20\ 550 F. 3d at 1178.
\21\ 76 FR 48207 (August 8, 2011).
\22\ CSAPR has been subject to extensive litigation, and on July
28, 2015, the D.C. Circuit issued a decision generally upholding
CSAPR but remanding without vacating the CSAPR emissions budgets for
a number of states. Louisiana's ozone season NO<INF>X</INF> budgets
were not included in the remand. EME Homer City Generation v. EPA,
795 F.3d 118, 138 (D.C. Cir. 2015). On October 26, 2016, we
finalized an update to CSAPR that addresses the 1997 ozone NAAQS
portion of the remand as well as the CAA requirements addressing
interstate transport for the 2008 ozone NAAQS. 81 FR 74504 (October
26, 2016).
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Both CAIR and CSAPR focused on achieving widespread reductions in
PM<INF>2.5</INF> precursor pollutants, which include SO<INF>2</INF>.
While the programs reduced SO<INF>2</INF> emissions from power plants,
they did so with the goal of reducing PM<INF>2.5</INF> levels, not with
the goal of preventing contribution to nonattainment or interference
with maintenance of the SO<INF>2</INF> standard. Louisiana did not
provide an analysis to show how the reductions from these programs
would sufficiently address SO<INF>2</INF> to prevent prohibited
impacts. Moreover, these rules required emissions reductions through
emissions trading programs for power plants. As such, they were not
designed to ensure a particular level of emissions reduction at a
particular power plant, and did not address SO<INF>2</INF> emissions at
all from non-power plant sources or emissions activities. Thus, despite
these programs, individual power plant and non-power plant sources that
are near State borders may be able to continue to emit at uncontrolled
levels, potentially contributing to SO<INF>2</INF> nonattainment or
maintenance issues in other States. As such, these programs alone
cannot be relied upon to demonstrate prohibited
[[Page 15216]]
interstate transport of SO<INF>2</INF> emissions were prevented.
While the rationale provided by Louisiana is not an adequate basis
on its own by which the EPA can determine the approvability of the
State's submission, the EPA may elect to consider additional
information to assist in reaching a conclusion as to whether the
submission may be approved, in whole or in part, as satisfying the
Act's requirements, or does not meet the Act's requirements. Here, the
EPA may consider all relevant information, or generate new data and
analysis, to make an independent judgment in evaluating States'
compliance with the good neighbor provision, which concerns the effects
of States' emissions in other States. Therefore, the EPA considered
additional available information as described below and in more detail
in the TSD for this action, to determine if Louisiana's SIP complies
with 110(a)(2)(D)(i)(I) requirements.
B. EPA's Evaluation Methodology
For this CAA section 110(a)(2)(D)(i)(I) evaluation of the 2010
SO<INF>2</INF> NAAQS, the EPA conducted a WOE analysis for Prong 1 and
Prong 2 separately,\23\ evaluating available information such as air
quality, emission sources, modeling and emission trends in Louisiana,
and the States that border Louisiana. To identify which sources and
emissions activities in Louisiana could potentially impact downwind air
quality in other States with respect to the 2010 1-hour SO<INF>2</INF>
NAAQS, the EPA used information in the EPA's National Emissions
Inventory (NEI) \24\ and Emissions Inventory System (EIS).\25\ The NEI
is a comprehensive and detailed estimate of air emissions for criteria
pollutants, criteria pollutant precursors, and hazardous air pollutants
from air emissions sources, updated every three years using information
provided by the States and other information available to the EPA. For
analyses, we largely relied on data from the 2020 NEI, because it is
the most recently available, complete, and quality assured dataset.
However, in evaluating emissions trends, both State-wide and at the
facility level, the EPA also considered data from prior NEI reports and
EIS queries, as part of the overall WOE analysis.
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\23\ In North Carolina v. EPA, 531 F.3d at 910-911 (D.C. Cir.
2008), the D.C. Circuit explained that the regulating authority must
give Prong 2 ``independent significance'' from Prong 1 by evaluating
the impact of upwind state emissions on downwind areas that, while
currently in attainment, are at risk of future nonattainment.
\24\ EPA's NEI is available and accessible to the public at
<a href="https://www.epa.gov/air-emissions-inventories/national-emissions-inventory">https://www.epa.gov/air-emissions-inventories/national-emissions-inventory</a>.
\25\ The EIS is EPA's database used to receive and store
emissions data and generate emissions inventories. The EIS Gateway
is a web-based tool developed to provide only registered EPA, State,
local and Tribal users with access to emission inventory data for
sources in their jurisdiction.
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As shown in Table 1, the majority of SO<INF>2</INF> emissions in
Louisiana originate from point sources. In 2020, total SO<INF>2</INF>
emissions from point sources in Louisiana comprised approximately 87
percent of the total SO<INF>2</INF> emissions in the State. Non-point
sources, on road and non-road emissions sources are individually much
smaller also more dispersed throughout the State and are therefore
unlikely to contribute to high ambient concentrations when compared to
point source contributions. Further analysis \26\ shows that facilities
with reported emissions greater than 100 tons per year (tpy) represent
approximately 6 percent of the total number of Louisiana SO<INF>2</INF>
point sources but are responsible for 82,980 tons of SO<INF>2</INF> or
97 percent of the total 2020 SO<INF>2</INF> emissions.\27\ Based on
this analysis, the EPA focused our WOE analysis on SO<INF>2</INF>
emissions from Louisiana's larger point sources (i.e., point sources
emitting over 100 tpy of SO<INF>2</INF>) that are located within 50 km
of one or more State borders.
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\26\ See EPA's TSD for a more detailed discussion.
\27\ See Table 9 in the EPA's TSD.
Table 1--Summary of 2020 SO2 Emissions in Louisiana by Source Category
------------------------------------------------------------------------
Percent of
2020 total SO2
Category emissions emissions
(tpy)
------------------------------------------------------------------------
Point.......................................... 85,239 87
Nonpoint....................................... 12,537 13
On road........................................ 158 <1
Nonroad........................................ 10 <1
------------------------
SO2 Emissions Total.......................... 97,999 100
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As described in this section, the EPA proposes that an assessment
of Louisiana's satisfaction of the Prong 1 and 2 requirements under CAA
section 110(a)(2)(D)(i)(I) for the 2010 1-hour SO<INF>2</INF> NAAQS may
be reasonably based upon several factors. These factors include
evaluation of the predicted downwind impacts projected in previous
relevant modeling studies for the source and nearby areas, assessment
of Louisiana's SO<INF>2</INF> point source emissions of more than 100
tpy of SO<INF>2</INF> per facility that are located within
approximately 50 km of another State, assessment of other States' point
sources emitting more than 100 tpy of SO<INF>2</INF> located within
approximately 50 km of Louisiana, and assessment of federal regulations
and SIP-approved regulations affecting Louisiana's SO<INF>2</INF>
sources. The EPA's evaluation is informed by all available data at the
time of this rulemaking.\28\
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\28\ EPA notes that the evaluation of other states' satisfaction
of section 110(a)(2)(D)(i)(I) for the 2010 1-hour SO<INF>2</INF>
NAAQS can be informed by similar factors found in this proposed
rulemaking but may not be identical to the approach taken in this or
any future rulemaking for Louisiana, depending on available
information and state-specific circumstances.
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The EPA notes that if this information were insufficient to draw a
reasonable conclusion concerning whether Louisiana is ``significantly
contributing'' or not, then it would not be possible to propose
approval based only on this information. In other words, in general,
the absence of information concerning whether interstate transport is
occurring is not in itself sufficient justification for approving a
good neighbor SIP submission. For example, if there were inadequate
monitoring or modeling information to characterize the effects of a
large, near-border source of SO<INF>2</INF> emissions, it may be
appropriate to conduct, or ask the State to conduct, further analysis
to better characterize that source and its effects, in order to reach a
determination concerning whether the good neighbor provision is being
met. See, e.g., 88 FR 41344 (June 26, 2023) (proposing approval of
Tennessee SO<INF>2</INF> transport SIP submission based on updated
modeling conducted to better characterize emissions from the Eastman
Chemical facility). In this case, the information available to the EPA,
as analyzed in the accompanying TSD and summarized below, is fully
sufficient to conclude that Louisiana is not and will not emit
SO<INF>2</INF> pollution in violation of the good neighbor provision
for the 2010 SO<INF>2</INF> NAAQS.
1. EPA's Prong 1 Evaluation--Contribute Significantly to Nonattainment
Prong 1 of the ``good neighbor'' provision requires States' plans
to prohibit emissions that will contribute significantly to
nonattainment of the NAAQS in another State. The EPA's evaluation \29\
of whether Louisiana has met its Prong 1 transport obligations was
accomplished by considering all available information, including the
following: SO<INF>2</INF> ambient air quality in Louisiana and
neighboring States; SO<INF>2</INF> emissions trends for Louisiana and
neighboring States; potential ambient impacts of SO<INF>2</INF>
emissions from certain
[[Page 15217]]
facilities \30\ in Louisiana on neighboring States; Louisiana's SIP-
approved regulations specific to SO<INF>2</INF> emissions and permit
requirements; and other SIP-approved or federally enforceable
regulations which may reduce SO<INF>2</INF> emissions either directly
or indirectly.
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\29\ A detailed review of EPA's evaluation of emissions, air
monitoring data, other technical information, and rationale for
proposed approval of this SIP revision as meeting CAA section
110(a)(2)(D)(i)(I) for the 2010 1-hour SO<INF>2</INF> NAAQS may be
found in the TSD.
\30\ The physical properties of SO<INF>2</INF> result in
relatively localized pollutant impacts near the emissions source.
Therefore, the EPA selected a spatial scale with dimensions up to 50
km from point sources.
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Based on the EPA's analysis, we propose to determine that there are
no SO<INF>2</INF> nonattainment issues in the relevant areas in other
States bordering Louisiana, and as such the EPA proposes to determine
that Louisiana's SIP satisfies the requirements of Prong 1 of CAA
section 110(a)(2)(D)(i)(I). This proposed determination is based on the
following considerations:
<bullet> There are no monitors recording violations of the 2010 1-
hour SO<INF>2</INF> NAAQS located in Louisiana including within 50 km
of its border. Additionally, all monitors within 50 km of the Louisiana
border have design values (DV) \31\ that are below the 75 ppb
SO<INF>2</INF> NAAQS. Current DVs for Louisiana's AQS SO<INF>2</INF>
monitors within 50 km of another State's border have remained below the
2010 1-hour SO<INF>2</INF> NAAQS from 2019-2023; similarly,
SO<INF>2</INF> monitors in neighboring States (Texas, Arkansas, and
Mississippi) within 50 km of Louisiana have 2023 DVs (2021-2023) below
the 2010 1-hour SO<INF>2</INF> NAAQS;
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\31\ The design value is the 3-year average of the 99th
percentile 1-hour daily maximums at a monitor. A control strategy
should be designed to bring the value to attainment of the standard.
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<bullet> Downward SO<INF>2</INF> emissions trends in Louisiana and
its surrounding States (Texas, Arkansas, and Mississippi), when
considered together with the other factors discussed as part of EPA's
WOE analysis, further support that Louisiana's sources will not
significantly contribute to any other States' nonattainment of the 2010
1-hour SO<INF>2</INF> NAAQS;
<bullet> A source-specific analyses of every Louisiana 100 tpy
source located within 50 km of the State border indicates that the
sources do not contribute to nonattainment in other States. These
analyses draw upon available emissions data, monitoring data, air
quality modeling, control retirements, wind rose data, and other
relevant information to assess the likelihood of air quality impacts
from these sources to areas in surrounding States. A detailed
discussion of each source-specific analysis is contained in section
IV.B.1 of the TSD accompanying this action. Below we cover some of the
principal evidence that confirms that emissions from Louisiana do not
contribute to nonattainment in other States.
[cir] The closest monitor to the Nelson facilities has consistently
recorded DVs well below the standard for years 2012-2023, indicating
that these facilities are not causing exceedances in Louisiana and
would not cause exceedances in Texas.
[cir] Now retired, the monitor in the vicinity of the Reynolds
facility in Calcasieu Parish recorded DVs well below the standard from
2017-2020. Considering this historic air quality data with emissions
trends in Calcasieu Parish (largely unchanged since 2017) support a
determination that these sources are not likely to contribute to
nonattainment in Texas.
[cir] Finally, the Orange monitor, located 2 km from the border of
Louisiana in Texas, has also recorded DVs below the standard from 2019-
2023, further supporting a determination that emissions from Calcasieu
Parish sources are not contributing to nonattainment across the border
with Texas.
[cir] For the St. Bernard Parish sources, nearby monitors
(Chalmette Vista and Meraux) have consistently recorded DVs below the
NAAQS. Coupling this monitored air quality information with the fact
that these sources are 49 km from the State line supports a
determination that emissions from these sources are not contributing to
nonattainment across the border into Mississippi.
[cir] For the sources in northwestern Louisiana, low DVs at the
Shreveport monitor, coupled with predominant wind patterns that are
more likely to transport emissions from these facilities to this
monitor than to Texas, support that the northwestern Louisiana sources
of emissions are unlikely contributing to nonattainment in Texas.
Additionally, DRR modeling results for Dolet Hills Power Station and
International Paper's Mansfield Mill indicate no SO<INF>2</INF> air
quality violations in DeSoto Parish. When considered with the facts
that Dolet Hills has since shutdown and emissions from Mansfield Mill
have since decreased, the modeling results are an overestimation of
current conditions, further supporting a determination that emissions
from Mansfield Mill will not contribute to nonattainment in Texas. For
the remainder of the northwestern Louisiana sources, wind rose data and
the size and distance (18 km to 48 km) between the sources and the
nearest border support a determination that these sources will not
contribute to nonattainment of the NAAQS in Texas.
[cir] For the Baton Rouge area sources, the EPA considered DRR
modeling from Big Cajun II that predicted maximum concentrations below
the standard within Pointe Coupee Parish. Coupling these results in
combination with the fact that emissions from the sources included in
the modeling have dropped 85% since the modeling was conducted supports
a determination that Big Cajun II will not contribute to nonattainment
of the NAAQS in Mississippi. Additionally, two active monitors (Capitol
and Port Allen) downwind of Oxbow have consistently low DVs, and given
Oxbow's 46 km distance from the border, this evidence further indicates
that these Baton Rouge area sources will not contribute to
nonattainment of the standard in Texas.
[cir] For the DeRidder Paper Mill, the small magnitude of the
source's SO<INF>2</INF> emissions, the lack of other nearby sources,
and wind rose data showing the lack of winds from the east, indicate
that this source is not contributing to nonattainment of the NAAQS in
Texas.
[cir] For the Bogalusa Mill, extrapolation of PSD modeling predicts
maximum impacts from the facility well below the standard, the small
magnitude of the source's SO<INF>2</INF> emissions, lack of any other
nearby sources, and wind rose data showing the lack of winds from the
west, support the EPA's determination that this source is not
contributing to nonattainment of the standard in Mississippi.
[cir] Further there are SIP-approved and federal emissions control
regulations within Louisiana that will continue to ensure that
SO<INF>2</INF> emissions will be effectively controlled for existing
and new sources or modifications.
Based on this evaluation, as more thoroughly discussed in our TSD
for this action, the EPA proposes to find that sources within Louisiana
will not significantly contribute to nonattainment of the 2010 1-hour
SO<INF>2</INF> NAAQS in any other State.
2. EPA's Prong 2 Evaluation--Interference With Maintenance
Prong 2 of the ``good neighbor'' provision requires State plans to
prohibit emissions that will interfere with maintenance of a NAAQS in
another State. The EPA's evaluation of whether Louisiana has met its
Prong 2 transport obligations was accomplished by considering all
available information, with a focus on current air quality data,
SO<INF>2</INF> emissions trends for Louisiana and neighboring States,
and how existing and future sources of SO<INF>2</INF> are addressed
through existing SIP-approved and federally enforceable regulations.
This evaluation builds upon the analysis
[[Page 15218]]
conducted for significant contribution to nonattainment (Prong 1),
which evaluated SO<INF>2</INF> ambient air quality in Louisiana and
neighboring States and potential ambient impacts of SO<INF>2</INF>
emissions from certain facilities in Louisiana on neighboring States.
Based on the EPA's analysis, we propose to find that SO<INF>2</INF>
levels in neighboring States near the Louisiana border do not indicate
an inability to maintain the SO<INF>2</INF> NAAQS that could be
attributed in part to sources in Louisiana, and as such the EPA
proposes to determine that Louisiana's SIP satisfies the requirements
of Prong 2 of CAA section 110(a)(2)(D)(i)(I). This determination is
based on the following considerations:
<bullet> Current 2021-2023 DVs for SO<INF>2</INF> monitors in
Louisiana within 50 km of another State's border and in neighboring
States (Texas, Arkansas, and Mississippi) within 50 km of Louisiana's
border are below the standard, indicating that these areas are all
currently in attainment of the 2010 1-hour SO<INF>2</INF> NAAQS;
<bullet> State-wide emissions trends in Louisiana and surrounding
States indicate generally declining SO<INF>2</INF> emissions and
consequently ambient air concentrations in the relevant areas;
<bullet> Source-specific analyses show that facility-level
emissions are decreasing as a result of emissions unit shutdowns and
control technology installation, indicating that emissions are not
anticipated to increase relative to baseline emissions;
<bullet> Current Louisiana statutes, SIP-approved measures, and
federal emissions control programs control SO<INF>2</INF> emissions
from certain sources within Louisiana; and
<bullet> Louisiana's SIP-approved PSD, major New Source Review
(NSR) regulations and minor source NSR permit programs address future
new and modified SO<INF>2</INF> sources above major and minor
permitting thresholds with the intent of ensuring that the
SO<INF>2</INF> NAAQS will not be exceeded as a result of new facility
construction or existing facility modification within the State or in
surrounding States.
Based on this evaluation, as more thoroughly discussed in our TSD
for this action, the EPA proposes to find that sources within Louisiana
will not interfere with maintenance of the 2010 1-hour SO<INF>2</INF>
NAAQS in any other State.
IV. Proposed Action
The EPA is proposing to approve the Prong 1 and Prong 2 portions of
the infrastructure SIP submission submitted by the State of Louisiana
on June 4, 2013, addressing interstate transport for the 2010 1-hour
SO<INF>2</INF> NAAQS. Based on the EPA's WOE analysis and as more
thoroughly discussed in the TSD, the EPA proposes to determine that
emissions from Louisiana will not contribute significantly to
nonattainment in, or interfere with maintenance of, any other State
with respect to the 2010 SO<INF>2</INF> NAAQS. We therefore propose to
find that Louisiana's SIP contains adequate provisions consistent with
CAA section 110(a)(2)(D)(i)(I).
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 Act and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, the 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 action:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Orders 12866 (58
FR 51735, October 4, 1993);
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> 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.);
<bullet> 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);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a State program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> 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 Clean Air Act.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where the EPA or an Indian Tribe
has demonstrated that a Tribe has jurisdiction. In those areas of
Indian country, the proposed rule does not have Tribal implications and
will not impose substantial direct costs on Tribal governments or
preempt Tribal law as specified by Executive Order 13175 (65 FR 67249,
November 9, 2000).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Sulfur dioxide, Reporting and
recordkeeping requirements.
Authority: 42 U.S.C. 7401 et seq.
Dated: March 21, 2025.
Walter Mason,
Regional Administrator, Region 6.
[FR Doc. 2025-05927 Filed 4-8-25; 8:45 am]
BILLING CODE 6560-50-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.