[Federal Register Volume 86, Number 122 (Tuesday, June 29, 2021)]
[Proposed Rules]
[Pages 34177-34187]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-13693]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[EPA-R07-OAR-2021-0391; FRL-10025-26-Region 7]


Air Plan Approval; Missouri Redesignation Request and Associated 
Maintenance Plan for the Jefferson County 2010 SO2 1-Hour NAAQS 
Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: On December 27, 2017, the State of Missouri submitted a 
request for the Environmental Protection Agency (EPA) to redesignate 
the Jefferson County, Missouri, 2010 1-hour sulfur dioxide 
(SO<INF>2</INF>) National Ambient Air Quality Standard (NAAQS) 
nonattainment area to attainment and to approve a State Implementation 
Plan (SIP) revision containing a maintenance plan for the area. The 
State provided supplemental information on: May 15, 2018; February 7, 
2019; February 25, 2019; and April 9, 2021. In response to these 
submittals, the EPA is proposing to take the following actions: Approve 
the State's plan for maintaining attainment of the 2010 1-hour 
SO<INF>2</INF> primary standard in the area; and approve the State's 
request to redesignate the Jefferson County SO<INF>2</INF> 
nonattainment area to attainment for the 2010 1-hour SO<INF>2</INF> 
primary standard.

DATES: Comments must be received on or before July 29, 2021.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-R07-
OAR-2021-0391 to https://www.regulations.gov. Follow the online 
instructions for submitting comments.
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received will be posted without 
change to https://www.regulations.gov/, including any personal 
information provided. For detailed instructions on sending comments and 
additional information on the rulemaking process, see the ``Written 
Comments'' heading of the SUPPLEMENTARY INFORMATION section of this 
document.

FOR FURTHER INFORMATION CONTACT: Ashley Keas, Environmental Protection 
Agency, Region 7 Office, Air Quality Planning Branch, 11201 Renner 
Boulevard, Lenexa, Kansas 66219 at (913) 551-7629 or by email at 
<a href="/cdn-cgi/l/email-protection#315a5450421f5042595d5448715441501f565e47"><span class="__cf_email__" data-cfemail="a7ccc2c6d489c6d4cfcbc2dee7c2d7c689c0c8d1">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: Throughout this document ``we,'' ``us,'' and 
``our'' refer to the EPA.

Table of Contents

I. Written Comments
II. Have the requirements for approval of a SIP revision been met?
III. What is the background for the EPA's proposed actions?
IV. What are the criteria for redesignation?
V. What is the EPA's analysis of the request?
VI. What are the actions the EPA is proposing to take?
VII. Environmental Justice Concerns
VIII. Incorporation by Reference
IX. Statutory and Executive Order Reviews

I. Written Comments

    Submit your comments, identified by Docket ID No. EPA-R07-OAR-2021-
0391, at https://www.regulations.gov. Once submitted, comments cannot 
be edited or removed from regulations.gov. 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

[[Page 34178]]

additional submission methods, the full EPA public comment policy, 
information about CBI or multimedia submissions, and general guidance 
on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

II. Have the requirements for approval of a SIP revision been met?

    The State submission has met the public notice requirements for SIP 
submissions in accordance with 40 CFR 51.102. The submission also 
satisfied the completeness criteria of 40 CFR part 51, appendix V. The 
State provided public notice on the December 2017 SIP submittal from 
July 31, 2017 to September 7, 2017 and held a public hearing on August 
31, 2017. The State received and addressed nineteen combined comments 
from a total of five sources. The State revised the maintenance plan 
based on public comment prior to submitting to the EPA.
    On April 9, 2021, Missouri submitted a supplement to the SIP 
revision to the EPA consisting of an addendum to the Consent Agreement 
between Ameren and Missouri. The Consent Agreement addendum 
incorporates monitoring, reporting and recordkeeping requirements 
needed to make the emissions limits contained in the Consent Agreement 
practically enforceable. Missouri held a public hearing for this SIP 
supplement on January 28, 2021 and made the supplement available for 
public review and comment from December 28, 2020 through February 4, 
2021. Missouri received supportive comments from Ameren.
    In addition, as explained above (and in more detail in the 
technical support document which is included in the docket for this 
action), the revision meets the substantive SIP requirements of the 
CAA, including section 110 and implementing regulations.

III. What is the background for the EPA's proposed actions?

    On June 2, 2010, the EPA revised the primary SO<INF>2</INF> NAAQS, 
establishing a new 1-hour standard of 75 parts per billion (ppb).\1\ 
Under the EPA's regulations at 40 CFR part 50, the 2010 1-hour 
SO<INF>2</INF> NAAQS is met at a monitoring site when the 3-year 
average of the annual 99th percentile of daily maximum 1-hour average 
concentrations is less than or equal to 75 ppb (based on the rounding 
convention in 40 CFR part 50, appendix T).\2\ Ambient air quality 
monitoring data for the 3-year period must meet a data completeness 
requirement. A year meets data completeness requirements when all four 
quarters are complete, and a quarter is complete when at least 75 
percent of the sampling days for each quarter have complete data. A 
sampling day has complete data if 75 percent of the hourly 
concentration values, including State-flagged data affected by 
exceptional events which have been approved for exclusion by the 
Administrator, are reported.\3\
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    \1\ See 75 FR 35520.
    \2\ See 40 CFR 50.17.
    \3\ 40 CFR part 50, appendix T, section 3(b).
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    Upon promulgation of a new or revised NAAQS, the CAA requires the 
EPA to designate as nonattainment any area that does not meet (or that 
contributes to ambient air quality in a nearby area that does not meet) 
the NAAQS.\4\ On August 5, 2013, the EPA designated a portion of 
Jefferson County, Missouri, as nonattainment for the 2010 1-hour 
primary SO<INF>2</INF> NAAQS, effective October 4, 2013.\5\ The 
designation was based on 2008-2010 monitoring data in Herculaneum, 
Missouri, which monitored violations of the standard (see section III 
of this document for additional monitoring information). This action 
established an attainment date five years after the effective date for 
the areas designated as nonattainment for the 2010 SO<INF>2</INF> NAAQS 
(i.e., by October 4, 2018). The State was also required to submit a SIP 
for the Jefferson County SO<INF>2</INF> nonattainment area to the EPA 
that meets the requirements of CAA sections 110, 172(c) and 191-192 
within 18 months following the October 4, 2013, effective date of 
designation (i.e., by April 4, 2015). The State of Missouri submitted 
the ``Nonattainment Area Plan for the 2010 1-Hour Sulfur Dioxide 
National Ambient Air Quality Standard Jefferson County Sulfur Dioxide 
Nonattainment Area'' on June 5, 2015, and subsequently withdrew the 
plan on March 30, 2018, following several intervening steps discussed 
later in this section.
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    \4\ CAA section 107(d)(1)(A)(i).
    \5\ 78 FR 47191 (August 5, 2013), codified at 40 CFR 81.326.
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    On February 2, 2016, the State submitted a request asking the EPA 
to determine that the Jefferson County SO<INF>2</INF> nonattainment 
area attained the 2010 1-hour primary SO<INF>2</INF> NAAQS per the 
EPA's Clean Data Policy. The clean data policy represents the EPA's 
interpretation that certain planning-related requirements of part D of 
the Act, such as the attainment demonstration, reasonably available 
control measures (RACM), and reasonable further progress (RFP), are 
suspended for areas that are in fact attaining the NAAQS. A 
determination of attainment, or clean data determination, does not 
constitute a formal redesignation to attainment. If the EPA 
subsequently determines that an area is no longer attaining the 
standard, those requirements that were suspended by the clean data 
determination are once again due.
    On June 23, 2017, the EPA published a notice of proposed rulemaking 
to approve the State's request for a clean data determination. The 
proposal was based on 2014-2016 monitoring data--the Mott Street 
monitor design value (dv) was 23 parts per billion (ppb)--and modeling 
data (a mix of 2013-2015 actual and allowable emissions).<SUP>6 7</SUP> 
After considering public comments received, the EPA published a Notice 
of Final Rulemaking (NFRM) approving the State's request for a clean 
data determination in the Federal Register on September 13, 2017.\8\
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    \6\ See 82 FR 28605.
    \7\ The State or Local Air Monitoring Station (SLAMS) was moved 
from Main Street to Mott Street in 2011 with EPA approval. The Mott 
Street SLAMS location was selected to characterize source specific 
(both SO<INF>2</INF> and lead) emissions from the Doe Run 
Herculaneum primary lead smelter.
    \8\ See 82 FR 42945.
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    On December 27, 2017, the State submitted a request for 
redesignation of the Jefferson County SO<INF>2</INF> nonattainment area 
to attainment and a SIP revision containing a 10-year maintenance plan 
for the area. On May 15, 2018, the State submitted a clarifying letter 
that Appendix A (containing the emissions inventory for the area) and 
Appendix B (containing a Consent Agreement for certain sources in the 
area) of the SIP submittal should be considered part of the SIP 
revision request. On February 7, 2019, and February 25, 2019, the State 
submitted supplemental modeling information to the EPA. On April 9, 
2021, the State submitted an addendum to the Consent Agreement which 
contains the emissions limits and monitoring, reporting, and 
recordkeeping requirements needed to determine compliance with the 
emissions limits for the covered sources. This proposal document 
discusses the EPA's review of the redesignation request, the 
maintenance plan (including Consent Agreement and addendum), and the 
supplemental information and provides support for the EPA's proposed 
approval of the request to redesignate the area to attainment and for 
proposed approval of the 10-year maintenance plan. Additional analysis 
of the redesignation request, 10-year maintenance plan, Consent 
Agreement and addendum, and supplemental modeling information is

[[Page 34179]]

provided in a Technical Support Document (TSD) included in the docket 
to this proposed rulemaking.\9\
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    \9\ The TSD discusses the EPA's review of the CAA section 
107(d)(3)(E) redesignation criteria: (i) A determination of 
attainment; (iii) a determination that the improvement in air 
quality is due to permanent and enforceable reductions in emissions; 
and (iv) a fully approved maintenance plan as well CAA section 175A 
maintenance plan criteria: (1) Attainment inventory; (2) maintenance 
demonstration; and (3) continued monitoring. The EPA's review of the 
remaining redesignation and maintenance plan criteria are 
sufficiently addressed in the preamble language to the NPRM.
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IV. What are the criteria for redesignation?

    The CAA provides the requirements for redesignating a nonattainment 
area to attainment. Specifically, section 107(d)(3)(E) of the CAA 
allows for redesignation of a nonattainment area provided that: (1) The 
Administrator determines that the area has attained the applicable 
NAAQS; (2) the Administrator has fully approved the applicable 
implementation plan for the area under section 110(k); (3) the 
Administrator determines that the improvement in air quality is due to 
permanent and enforceable reductions in emissions resulting from 
implementation of the applicable SIP and applicable federal air 
pollutant control regulations and other permanent and enforceable 
reductions; (4) the Administrator has fully approved a maintenance plan 
for the area as meeting the requirements of section 175A; and (5) the 
State containing such area has met all requirements applicable to the 
area under section 110 and part D of the CAA.

V. What is the EPA's analysis of the request?

    The EPA's evaluation of Missouri's redesignation request and 
maintenance plan is based on consideration of the five redesignation 
criteria provided under CAA section 107(d)(3)(E) and relevant guidance. 
On April 16, 1992, the EPA provided guidance on redesignation in the 
General Preamble for the Implementation of title I of the CAA 
Amendments of 1990 and supplemented this guidance on April 28, 
1992.<SUP>10 11</SUP> The EPA has provided further guidance on 
processing redesignation requests in several guidance documents. For 
the purposes of this action, the EPA will be referencing two of these 
documents: (1) The September 4, 1992 memo ``Procedures for Processing 
Requests to Redesignate Areas to Attainment'' (Calcagni Memo); and (2) 
the EPA's April 23, 2014 memorandum ``Guidance for 1-Hour 
SO<INF>2</INF> Nonattainment Area SIP Submissions'' (2014 
SO<INF>2</INF> Guidance).\12\
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    \10\ See 57 FR 13498.
    \11\ See 57 FR 18070.
    \12\ https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf.
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Criterion (1)--The Jefferson County SO2 Nonattainment Area Has Attained 
the 2010 1-Hour SO2 NAAQS

    For redesignating a nonattainment area to attainment, the CAA 
requires the EPA to determine that the area has attained the applicable 
NAAQS (CAA section 107(d)(3)(E)(i)). The EPA determined that the area 
attained the 2010 1-hour SO<INF>2</INF> NAAQS in its September 2017 
NFRM approving the State's request for a clean data determination 
meeting the requirements of CAA section 107(d)(3)(E)(i). That 
determination was primarily based on a modeling analysis of recent 
actual emissions for sources in and around the nonattainment area. As 
described further in the TSD for this action, the Supplemental modeling 
submitted by Missouri in February 2019 to support the redesignation 
request and maintenance plan is based on a modeling demonstration of 
permanent and enforceable emissions at sources in the nonattainment 
area that similarly demonstrates the area is attaining the standard. 
Therefore, the EPA's determination that the area had achieved clean 
data is consistent with the proposed action to redesignate the area.
    Following the EPA's determination that the area had achieved clean 
data, the EPA reviewed quality assured monitoring data recorded in the 
EPA's Air Quality System (AQS) from the Mott Street monitoring station. 
The 3-year, 2018-2020 design value for the Mott Street monitor is 14 
ppb and continues to meet the 2010 1-hour SO<INF>2</INF> NAAQS, as 
shown in Table 1. If the 3-year design value violates the NAAQS prior 
to the EPA acting in response to the State's request, the EPA will not 
take final action to approve the redesignation request.\13\ As 
discussed in more detail later in this section, Missouri has committed 
to continue monitoring in this area in accordance with 40 CFR part 58.
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    \13\ See 2014 SO<INF>2</INF> Guidance, at 56.

                Table 1--2015-2020 Mott Street Monitor Data (parts per billion (ppb)); 99th Percentile (99%) and 3-Year Design Value (dv)
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                                                  2015     2016     2017     2018     2019     2020    2015-2017    2016-2018    2017-2019    2018-2020
                     Site                        99th %   99th %   99th %   99th %   99th %   99th %       dv           dv           dv           dv
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Mott Street...................................      38       13       18       12       12       17           23           14           14           14
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 Criterion (2)--Missouri Has a Fully Approved SIP Under Section 110(k); 
and Criterion (5)--Missouri Has Met All Applicable Requirements Under 
Section 110 and Part D of Title I of the CAA

    For redesignating a nonattainment area to attainment under a NAAQS, 
the CAA requires the EPA to determine that the State has met all 
applicable requirements for that NAAQS under section 110 and part D of 
title I of the CAA (CAA section 107(d)(3)(E)(v)) and that the State has 
a fully approved SIP under section 110(k) for that NAAQS for the area 
(CAA section 107(d)(3)(E)(ii)). The EPA proposes to find that Missouri 
has met all applicable SIP requirements for purposes of redesignation 
for the Jefferson County SO<INF>2</INF> nonattainment area under 
section 110 of the CAA (general SIP requirements). Additionally, the 
EPA proposes to find that the Missouri SIP satisfies the criterion that 
it meets applicable SIP requirements for purposes of redesignation 
under part D of title I of the CAA in accordance with section 
107(d)(3)(E)(v). Further, the EPA proposes to determine that the SIP is 
fully approved with respect to all requirements applicable for the 2010 
1-hour SO<INF>2</INF> NAAQS for purposes of redesignation in accordance 
with section 107(d)(3)(E)(ii). In proposing to make these 
determinations, the EPA ascertained which requirements are applicable 
to the Jefferson County SO<INF>2</INF> nonattainment area and, if 
applicable, that they are fully approved under section 110(k).

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a. The Jefferson County SO<INF>2</INF> Nonattainment Area Has Met All 
Applicable Requirements Under Section 110 and Part D of the CAA
    General SIP requirements. General SIP elements and requirements are 
delineated in section 110(a)(2) of title I, part A of the CAA. These 
requirements include, but are not limited to, the following: Submittal 
of a SIP that has been adopted by the State after reasonable public 
notice and hearing; provisions for establishment and operation of 
appropriate procedures needed to monitor ambient air quality; 
implementation of a source permit program; provisions for the 
implementation of part C requirements (Prevention of Significant 
Deterioration (PSD)) and provisions for the implementation of part D 
requirements (New Source Review (NSR) permit programs); provisions for 
air pollution modeling; and provisions for public and local agency 
participation in planning and emissions control rule development.
    Section 110(a)(2)(D) requires that SIPs contain certain measures to 
prevent sources in a State from significantly contributing to air 
quality problems in another State. To implement this provision, the EPA 
has required certain States to establish programs to address the 
interstate transport of air pollutants. The section 110(a)(2)(D) 
requirements for a State are not linked with a nonattainment area's 
designation and classification in that State. The EPA believes that the 
requirements linked with a nonattainment area's designation and 
classifications are the relevant measures to evaluate in reviewing a 
redesignation request. The transport SIP submittal requirements, where 
applicable, continue to apply to a State regardless of the designation 
of any one area in the State. Thus, the EPA does not believe that the 
CAA's interstate transport requirements should be construed to be 
applicable requirements for purposes of redesignation.
    In addition, the EPA believes other section 110 elements that are 
neither connected with nonattainment plan submissions nor linked with 
an area's attainment status are applicable requirements for purposes of 
redesignation. The area will still be subject to these requirements 
after the area is redesignated. The section 110 and part D requirements 
which are linked with an area's designation and classification are the 
relevant measures to evaluate in reviewing a redesignation request. 
This approach is consistent with the EPA's existing policy on 
applicability (i.e., for redesignations) of conformity and oxygenated 
fuels requirements, as well as with section 184 ozone transport 
requirements.\14\
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    \14\ See Reading, Pennsylvania, proposed and final rulemakings 
(61 FR 53174-53176, October 10, 1996), (62 FR 24826, May 7, 2008); 
Cleveland-Akron-Loraine, Ohio, final rulemaking (61 FR 20458, May 7, 
1996); and Tampa, Florida, final rulemaking at (60 FR 62748, 
December 7, 1995). See also the discussion on this issue in the 
Cincinnati, Ohio, redesignation (65 FR 37890, June 19, 2000), and in 
the Pittsburgh, Pennsylvania, redesignation (66 FR 50399, October 
19, 2001).
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    Title I, part D, applicable SIP requirements. Section 172(c) of the 
CAA sets forth the basic requirements of attainment plans for 
nonattainment areas that are required to submit them pursuant to 
section 172(b). Subpart 5 of part D, which includes section 191 and 192 
of the CAA, establishes requirements for SO<INF>2,</INF> nitrogen 
dioxide and lead nonattainment areas. A thorough discussion of the 
requirements contained in sections 172(c) can be found in the General 
Preamble for Implementation of Title I.\15\
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    \15\ See 57 FR 13498.
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    Section 172 and subpart 5 requirements. Section 172(c)(1) requires 
the plans for all nonattainment areas to provide for the implementation 
of all RACM as expeditiously as practicable and to provide for 
attainment of the NAAQS. The EPA interprets this requirement to impose 
a duty on all nonattainment areas to consider all available control 
measures and to adopt and implement such measures as are reasonably 
available for implementation in each area as components of the area's 
attainment demonstration. Under section 172, States with nonattainment 
areas must submit plans providing for timely attainment and meeting a 
variety of other requirements.
    The EPA's longstanding interpretation of the nonattainment planning 
requirements of section 172 is that once an area is attaining the 
NAAQS, those requirements are not ``applicable'' for purposes of CAA 
section 107(d)(3)(E)(ii) and (v) and therefore need not be approved 
into the SIP before the EPA can redesignate the area. In the 1992 
General Preamble for Implementation of Title I, the EPA set forth its 
interpretation of applicable requirements for purposes of evaluating 
redesignation requests when an area is attaining a standard.\16\ The 
EPA noted that the requirements for RFP and other measures designed to 
provide for attainment do not apply in evaluating redesignation 
requests because those nonattainment planning requirements ``have no 
meaning'' for an area that has already attained the standard.\17\ This 
interpretation was also set forth in the Calcagni Memo. The EPA's 
understanding of section 172 also forms the basis of its Clean Data 
Policy, which was articulated with regard to the 2010 1-hour 
SO<INF>2</INF> NAAQS in the EPA's 2014 SO<INF>2</INF> Guidance, and 
suspends a State's obligation to submit most of the attainment planning 
requirements that would otherwise apply, including an attainment 
demonstration and planning SIPs to provide for RFP, RACM, and 
contingency measures under section 172(c)(9). Courts have upheld the 
EPA's interpretation of section 172(c)(1) for ``reasonably available'' 
control measures and control technology as meaning only those controls 
that advance attainment, which precludes the need to require additional 
measures where an area is already attaining.\18\
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    \16\ See 57 FR 13498, 13564.
    \17\ Id.
    \18\ NRDC v. EPA, 571 F.3d 1245, 1252 (D.C. Cir. 2009); Sierra 
Club v. EPA, 294 F.3d 155, 162 (D.C. Cir. 2002); Sierra Club v. EPA, 
314 F.3d 735, 744 (5th Cir. 2002); Sierra Club v. EPA, 375 F.3d 537 
(7th Cir. 2004). But see Sierra Club v. EPA, 793 F.3d 656 (6th Cir. 
2015).
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    Therefore, because the Jefferson County SO<INF>2</INF> 
nonattainment area is currently attaining the 2010 1-hour 
SO<INF>2</INF> NAAQS, no additional measures are needed to provide for 
attainment, and section 172(c)(1) requirements for an attainment 
demonstration and RACM are not part of the ``applicable implementation 
plan'' required to have been approved prior to redesignation per CAA 
section 107(d)(3)(E)(ii) and (v). The other section 172 requirements 
that are designed to help an area achieve attainment--the section 
172(c)(2) requirement that nonattainment plans contain provisions 
promoting reasonable further progress, the requirement to submit the 
section 172(c)(9) contingency measures, and the section 172(c)(6) 
requirement for the SIP to contain control measures necessary to 
provide for attainment of the NAAQS--are also not required to be 
approved as part of the ``applicable implementation plan'' for purposes 
of satisfying CAA section 107(d)(3)(E)(ii) and (v).
    Section 172(c)(3) requires submission and approval of a 
comprehensive, accurate, and current inventory of actual emissions. The 
requirement for an emissions inventory can be satisfied by meeting the 
inventory requirements of the maintenance plan.\19\ However, when the 
State withdrew its attainment plan for the area in March 2018, it did 
not withdraw the baseline emissions inventory submitted with that plan. 
On November 23, 2018, the EPA published a notice of proposed rulemaking 
in the Federal Register proposing to approve that the State met the 
section 172(c)(3)

[[Page 34181]]

requirement to submit an emissions inventory for the Jefferson County 
SO<INF>2</INF> nonattainment area.\20\ On February 13, 2019, the EPA 
published a final rulemaking in the Federal Register approving the 
State's emissions inventory for the Jefferson County SO<INF>2</INF> 
nonattainment area.\21\
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    \19\ Calcagni Memo at 6.
    \20\ See 83 FR 59348.
    \21\ See 84 FR 3703.
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    Section 172(c)(4) requires the identification and quantification of 
allowable emissions for major new and modified stationary sources to be 
allowed in an area, and section 172(c)(5) requires source permits for 
the construction and operation of new and modified major stationary 
sources anywhere in the nonattainment area. The State has an approved 
nonattainment NSR program.\22\ Regardless, the State has demonstrated 
that the Jefferson County SO<INF>2</INF> nonattainment area will be 
able to maintain the NAAQS without part D NSR in effect. Missouri's PSD 
program will be in effect in the Jefferson County SO<INF>2</INF> 
nonattainment area upon redesignation to attainment.
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    \22\ See 80 FR 31844.
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    Section 172(c)(7) requires the SIP to meet the applicable 
provisions of section 110(a)(2). As noted above, the EPA believes the 
Missouri SIP meets the requirements of section 110(a)(2) applicable for 
purposes of redesignation.
    Section 176 conformity requirements. Section 176(c) of the CAA 
requires States to establish criteria and procedures to ensure that 
federally supported or funded projects conform to the air quality 
planning goals in the applicable SIP. The requirement to determine 
conformity applies to transportation plans, programs, and projects that 
are developed, funded, or approved under title 23 of the United States 
Code (U.S.C.) and the Federal Transit Act (transportation conformity) 
as well as to all other federally supported or funded projects (general 
conformity). State transportation conformity SIP revisions must be 
consistent with federal conformity regulations relating to 
consultation, enforcement, and enforceability that the EPA promulgated 
pursuant to its authority under the CAA.
    Missouri has an approved general conformity SIP.\23\ Moreover, the 
EPA interprets the conformity SIP requirements as not applying for 
purposes of evaluating a redesignation request under section 107(d) 
because, like other requirements listed above, State conformity rules 
are still required after redesignation and federal conformity rules 
apply where State rules have not been approved.\24\
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    \23\ See 78 FR 57267.
    \24\ See Wall v. EPA, 265 F.3d 426 (6th Cir. 2001) (upholding 
this interpretation); see also 60 FR 62748 (December 7, 1995) 
(redesignation of Tampa, Florida).
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    As noted in the 2014 SO<INF>2</INF> Guidance, transportation 
conformity is required under CAA section 176(c) to ensure that 
federally supported highway and transit project activities are 
consistent with (``conform to'') the purpose of the SIP. Transportation 
conformity applies to areas that are designated nonattainment, and 
those areas redesignated to attainment (``maintenance areas'' with 
plans developed under CAA section 175A) for transportation-related 
criteria pollutants. Due to the relatively small, and decreasing, 
amounts of sulfur in gasoline and on-road diesel fuel, the EPA's 
conformity rules provide that they do not apply to SO<INF>2</INF> 
unless either the EPA Regional Administrator or the director of the 
State air agency has found that transportation-related emissions of 
SO<INF>2</INF> as a precursor are a significant contributor to a 
PM<INF>2.5</INF> nonattainment problem, or if the SIP has established 
an approved or adequate budget for such emissions as part of the RFP, 
attainment or maintenance strategy.\25\ Neither the EPA nor Missouri 
has made such a finding for transportation related emissions of 
SO<INF>2</INF> for the Jefferson County SO<INF>2</INF> nonattainment 
area.
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    \25\ See 40 CFR 93.102(b)(1), (2)(v).
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    For these reasons, the EPA proposes to find that Missouri has 
satisfied all applicable requirements for purposes of redesignation of 
the Jefferson County SO<INF>2</INF> nonattainment area under section 
110 and part D of title I of the CAA.
b. The Jefferson County SO<INF>2</INF> Nonattainment Area Has a Fully 
Approved Applicable SIP Under Section 110(k) of the CAA
    The EPA has fully approved the applicable Missouri SIP for the 
Jefferson County SO<INF>2</INF> nonattainment area under section 110(k) 
of the CAA for all requirements applicable for purposes of 
redesignation. As indicated above, the EPA believes that the section 
110 elements that are neither connected with nonattainment plan 
submissions nor linked to an area's attainment status are not 
applicable requirements for purposes of redesignation. The EPA has 
approved all part D requirements applicable under the 2010 
SO<INF>2</INF> NAAQS, as identified above, for purposes of this 
redesignation.

Criterion (3)--The Air Quality Improvement in the Jefferson County SO2 
Nonattainment Area Is Due to Permanent and Enforceable Reductions in 
Emissions

    For redesignating a nonattainment area to attainment, the CAA 
requires the EPA to determine that the air quality improvement in the 
area is due to permanent and enforceable reductions in emissions 
resulting from implementation of the SIP, applicable federal air 
pollution control regulations, and other permanent and enforceable 
reductions (CAA section 107(d)(3)(E)(iii)). The EPA proposes to find 
that Missouri has demonstrated that the observed air quality 
improvement in the Jefferson County SO<INF>2</INF> nonattainment area 
is due to permanent and enforceable reductions in emissions. 
Specifically, the EPA considers the shutdown of the Doe Run Herculaneum 
primary lead smelter (lead smelter), identified as the key contributor 
to the SO<INF>2</INF> NAAQS violations at the Mott Street monitor, to 
be both permanent and enforceable.\26\ As stated on page 10 of the 
Calcagni Memo, ``Emission reductions from source shutdowns can be 
considered permanent and enforceable to the extent that those shutdowns 
have been reflected in the SIP and all applicable permits have been 
modified accordingly.'' The lead smelter was limited to the terms of a 
consent decree entered by Doe Run, Missouri, and the EPA in the United 
States District Court in the Eastern District of Missouri (2011 Consent 
Decree).\27\ On December 31, 2013, pursuant to the terms of the 2011 
Consent Decree, the lead smelter permanently ceased operations of the 
sintering plant. The 2011 Consent Decree also required the lead smelter 
to permanently cease smelting operations and retire the blast furnaces 
by April 30, 2014; the lead smelter ceased operation of the blast 
furnaces on December 31, 2013, concurrently with the cessation of 
operation of the sintering plant. In addition, the Consent Decree 
required Doe Run to surrender air permits for the emission units 
required to be permanently shut down by the Consent Decree. Given the 
well-established correlation of much lower SO<INF>2</INF> emissions at 
the Mott Street monitor during periods when the lead smelter has been 
shut down, the EPA

[[Page 34182]]

anticipates that the SO<INF>2</INF> NAAQS will continue to be attained. 
See Table 1 for recent monitoring data trends at this monitor.
---------------------------------------------------------------------------

    \26\ See EPA's final Technical Support Document (TSD) for the 
Jefferson County SO<INF>2</INF> Nonattainment Area, in the docket 
for EPA's initial round of 2010 SO<INF>2</INF> designations at EPA-
HQ-OAR-2012-0233-0318.
    \27\ Case No. 4:10-cv-01895-JCH on December 21, 2011.
---------------------------------------------------------------------------

    Additionally, the State entered into a Consent Agreement with 
Ameren Missouri (Ameren), included as Appendix B to the maintenance 
plan submission, limiting the SO<INF>2</INF> emissions from three 
Ameren facilities. One facility, Ameren-Rush Island Energy Center (Rush 
Island), is located within the nonattainment area boundary. The other 
two facilities, Ameren Meramec Energy Center (Meramec) and Ameren 
Labadie Energy Center (Labadie) are located outside of the 
nonattainment area boundary. The Consent Agreement emission limits are 
provided in Table 2.

                         Table 2--Ameren/Missouri Consent Agreement SO2 Emission Limits
----------------------------------------------------------------------------------------------------------------
                                                 Emission limit
                    Source                         per source                     Averaging time
                                               (pounds per hour)
----------------------------------------------------------------------------------------------------------------
Labadie......................................             40,837  24-hr block average.
Meramec......................................              7,371  24-hr block average.
Rush Island..................................             13,600  24-hr block average.
----------------------------------------------------------------------------------------------------------------

    Because it is located inside of the Jefferson County SO<INF>2</INF> 
nonattainment area, the State modeled Rush Island at a constant 
emission rate of 14,600 lbs SO<INF>2</INF>/hr for every hour of the 
year in all five years (2013-2017) of the modeling analysis. This 
modeled emission rate corresponds to the facility's enforceable 24-hour 
block average limit for hourly SO<INF>2</INF> emissions of 13,600 lbs 
SO<INF>2</INF>/hr when accounting for variability. The State modeled 
Meramec and Labadie as nearby sources in accordance with the code of 
federal regulations (CFR) 40 CFR part 51, appendix W, Guideline on Air 
Quality Models. That is, the State modeled Meramec and Labadie's 
permitted/allowable emission rate from the Consent Agreement with 
actual temporally varying heat input levels. Please see the TSD for 
details of the modeling inputs and additional discussion of the air 
quality modeling. The modeling results demonstrate attainment and 
project continued maintenance of the NAAQS, and the TSD also contains 
discussion of the EPA's review of the modeling.
    Therefore, the EPA is proposing to find that the air quality 
improvement in the Jefferson County SO<INF>2</INF> nonattainment area 
is due to permanent and enforceable reductions in emissions.

Criterion (4)--The Jefferson County SO2 Nonattainment Area Has a Fully 
Approved Maintenance Plan Pursuant to Section 175A of the CAA

    To redesignate a nonattainment area to attainment, the CAA requires 
the EPA to determine that the area has a fully approved maintenance 
plan pursuant to section 175A of the CAA (CAA section 
107(d)(3)(E)(iv)). In conjunction with its request to redesignate the 
Jefferson County SO<INF>2</INF> nonattainment area to attainment for 
the 2010 1-hour SO<INF>2</INF> NAAQS, the State submitted a SIP 
revision to provide for the maintenance of the 2010 1-hour 
SO<INF>2</INF> NAAQS for at least 10 years after the effective date of 
redesignation to attainment. The EPA is proposing to find that this 
maintenance plan for the area meets the requirements for approval under 
section 175A of the CAA.
a. What is required in a maintenance plan?
    CAA section 175A sets forth the elements of a maintenance plan for 
areas seeking redesignation from nonattainment to attainment. Under 
section 175A, the plan must demonstrate continued attainment of the 
applicable NAAQS for at least 10 years after the Administrator approves 
a redesignation request to attainment. Eight years after the 
redesignation, the State must submit a revised maintenance plan 
demonstrating that attainment will continue to be maintained for the 10 
years following the initial 10-year period. To address the possibility 
of future NAAQS violations, the maintenance plan must contain 
contingency measures as the EPA deems necessary to assure prompt 
correction of any future 2010 1-hour SO<INF>2</INF> violations. The 
Calcagni Memo provides further guidance on the content of a maintenance 
plan, explaining that a maintenance plan should address five 
requirements: The attainment emissions inventory, maintenance 
demonstration, monitoring, verification of continued attainment, and a 
contingency plan. As is discussed more fully later in this section, the 
EPA is proposing to determine that Missouri's maintenance plan includes 
all the necessary components and is thus proposing to approve it as a 
revision to the Missouri SIP.
b. Attainment Emissions Inventory
    As part of a State's maintenance plan, the air agency should 
develop an attainment inventory to identify the level of emissions in 
the affected area which is enough to attain and maintain the 
SO<INF>2</INF> NAAQS.\28\ The EPA is proposing to approve that Missouri 
has met this requirement through modeling of permanent and enforceable 
emissions limits that will result in continued attainment and 
maintenance of the NAAQS. Missouri also provided emissions inventories 
as part of the maintenance plan. Specifically, Missouri selected 2014 
as the attainment emissions inventory year for developing an emissions 
inventory for SO<INF>2</INF> in the nonattainment area through 2030. 
Please see the TSD included in the docket for this action for details 
of the base year, attainment year and future year emissions inventories 
and the EPA's review of these inventories. The TSD also details the 
EPA's review of the modeling demonstration provided by Missouri which 
forms the basis for the EPA's approval of this maintenance plan 
requirement.
---------------------------------------------------------------------------

    \28\ See 2014 SO<INF>2</INF> Guidance, at 66.
---------------------------------------------------------------------------

c. Maintenance Demonstration
    The Calcagni memo describes two ways for a State to demonstrate 
maintenance of the NAAQS for a period of at least 10 years following 
the redesignation of the area: (1) The State can show that future 
emissions of a pollutant will not exceed the level of the attainment 
inventory, or (2) the State can model to show that the future mix of 
sources and emission rates will not cause a violation of the standard. 
The memo goes on to say that areas that are required to model to 
demonstrate attainment of the standard should complete the same level 
of modeling to demonstrate that the permanent and enforceable emissions 
are enough to maintain the standard. The State performed several 
modeling iterations to demonstrate that the standard will be 
maintained. In its February 7, 2019, and February 25, 2019, 
supplemental

[[Page 34183]]

modeling, Missouri has demonstrated maintenance by modeling all sources 
inside of the nonattainment area at their permanent, enforceable, 
allowable emission rates, nearby sources at their permanent, 
enforceable, allowable emission rates (with actual operating conditions 
for 2013-2017), and other sources addressed through the use of a 
background concentration. The EPA proposes that the supplemental 
modeling provided by Missouri demonstrates the standard will be 
attained and maintained for at least 10 years following redesignation 
of the area, consistent with the second method outlined in the Calcagni 
memo by which a State may demonstrate maintenance of the NAAQS. Please 
see the TSD for details of the modeling inputs, results and the EPA's 
review of them. The EPA is proposing to approve Missouri's maintenance 
plan including the supplemental modeling and a background concentration 
revised by the EPA as meeting the maintenance demonstration 
requirement.
d. Monitoring Network
    Missouri has committed to continue operating the ``appropriate 
SO<INF>2</INF> network in the Jefferson County nonattainment area'' in 
accordance with the requirements of 40 CFR part 58, and approved annual 
monitoring network plans, to verify the attainment status of the area. 
The State committed to quality assure the data in accordance with 40 
CFR part 58 and submit the data to the EPA's air quality system (AQS). 
The maintenance plan, consistent with the State's 2019 annual ambient 
monitoring network plan, indicate that the Mott Street monitor is the 
only SLAMS or SLAMS like monitor operational in the nonattainment 
area.\29\
---------------------------------------------------------------------------

    \29\ See Missouri's 2019 Ambient Monitoring Network Plan 
contained in the docket for this action.
---------------------------------------------------------------------------

    There are also three industrial source monitors located around Rush 
Island.\30\ These monitors are required per the Consent Agreement 
between Ameren and the State.\31\ The Consent Agreement required the 
monitors to start operation by December 2015 and operate 12 consecutive 
quarters (3 years). The industrial source monitors have also been 
identified in the State's annual ambient monitoring network plans since 
2015.\32\ The Consent Agreement also requires certain responses by 
Ameren if elevated monitoring values are recorded at any of the 
industrial source monitors.
---------------------------------------------------------------------------

    \30\ The industrial monitors are not classified as SLAMS nor as 
Data Requirements Rule monitors.
    \31\ The Consent Agreement is included as Appendix B of the 
maintenance plan.
    \32\ The EPA approved the State's 2019 Ambient Monitoring 
Network Plan via letter dated January 8, 2021. Missouri's 2019 Plan 
and the EPA's approval letter are included in the docket for this 
action.
---------------------------------------------------------------------------

    The maintenance plan and Consent Agreement requires Ameren to 
operate the industrial source monitors for a minimum of 12 consecutive 
quarters. The maintenance plan and Consent Agreement do not establish 
that the monitors must be operated as SLAMS-like monitors which would 
make them subject to the discontinuation requirements of 40 CFR part 
58.\33\ However, because the EPA is proposing to approve the 
requirement to operate the industrial source monitors, and that the 
contingency measures may be triggered by data recorded by these 
industrial source monitors, as contained in the Consent Agreement, into 
the SIP, the monitors must operate until the EPA approves a revision to 
the SIP to remove the monitoring requirements.
---------------------------------------------------------------------------

    \33\ However, the EPA notes that the industrial source monitors 
are operated in accordance with an approved industrial source 
monitoring quality assurance project plan (QAPP) and quality 
management plan (QMP). The relevant QAPP and QMP documents are 
included in the docket for this action. The QMP outlines the quality 
assurance audits to be conducted by Missouri staff to ensure the 
industrial monitoring data is collected in a manner equivalent to 
SLAMS and may be used to determine NAAQS compliance. See Missouri's 
2016 Ambient Monitoring Network Plan contained in the docket for 
this action for more information.
---------------------------------------------------------------------------

    Because the industrial source monitors were not identified by the 
State as necessary to meet the requirements of the Data Requirements 
Rule (DRR) they are not subject to the requirements of 40 CFR 
51.1203(c).\34\ The 2018 annual monitoring network plan commits the 
State to ``continuing to work with Ameren to collect quality assured 
SO<INF>2</INF> ambient air quality data and meteorological data near 
the Rush Island power station to provide quantifiable and useful 
information to supplement the ongoing 1-hour SO<INF>2</INF> NAAQS 
implementation process.''
---------------------------------------------------------------------------

    \34\ The EPA promulgated the DRR August 21, 2015. The DRR 
requires air agencies to characterize air quality, either by 
monitoring or modeling, around sources that emit 2,000 tons per year 
(tpy) or more of SO<INF>2</INF>. The requirement for air quality 
characterization near a source may be avoided by adopting 
enforceable emission limits that ensure that the source will not 
emit more than 2,000 tpy of SO<INF>2</INF>. On January 15, 2016, the 
State submitted a final list identifying the sources in the State 
around which SO<INF>2</INF> air quality will be characterized. Rush 
Island was not included in the list because it is within the 
Jefferson County SO<INF>2</INF> nonattainment area. Starting in 
2016, Missouri's annual monitoring network plans state that 
monitoring around Rush Island is being conducted by agreement 
between the State and Ameren.
---------------------------------------------------------------------------

    Because there is no regulatory obligation, or commitment from 
Ameren or the State to operate the industrial source monitors as SLAMS-
like or for the duration of the maintenance period, the EPA is 
proposing to approve that the State is meeting its obligation to 
continue monitoring in the area, and verify ongoing attainment and 
maintenance, via operation of the Mott Street SLAMS monitor and that 
Missouri's maintenance plan meets the ``Monitoring Network'' 
requirement.\35\ However, as previously noted, because the EPA is 
proposing to approve the Consent Agreement into the SIP, continued 
operation of the industrial source monitors will be required until the 
EPA approves a revision to the SIP to remove the monitoring 
requirements.\36\ The available recent monitoring data from these 
industrial monitors is included in the TSD associated with this action.
---------------------------------------------------------------------------

    \35\ Any change in the operational status or location of the 
Mott Street monitor must be approved by the Regional Administrator 
in accordance with the requirements of 40 CFR part 58.
    \36\ The EPA would also need to approve the monitor changes as 
part of the State's annual monitoring network plan.
---------------------------------------------------------------------------

e. Verification of Continued Attainment
    Each air agency should ensure that it has the legal authority to 
implement and enforce all measures necessary to attain and maintain the 
2010 SO<INF>2</INF> NAAQS. The air agency's submittal should indicate 
how it will track the progress of the maintenance plan for the area 
either through air quality monitoring or modeling.\37\
---------------------------------------------------------------------------

    \37\ See 2014 SO<INF>2</INF> Guidance at 67-68.
---------------------------------------------------------------------------

    Missouri has the legal authority to enforce and implement the 
maintenance plan for the Jefferson County 2010 SO<INF>2</INF> 
nonattainment area. This includes the authority to adopt, implement, 
and enforce any subsequent emissions control contingency measures 
determined to be necessary to correct future SO<INF>2</INF> attainment 
problems.\38\ As noted, the State will track the progress of the 
maintenance plan by continuing to operate the Mott Street monitor. 
Additionally, the State committed to provide future inventory updates 
to track emissions during the 10-year maintenance period. State 
Regulation 10 CSR 10-6.110, Reporting Emission Data, Emission Fees, and 
Process Information, (which is SIP approved) requires that all 
installations with a construction or operating permit report its annual 
emissions to the State. The methods for calculating and reporting 
emissions are detailed in each installation's applicable permit. The 
data collected on emissions inventory questionnaires from permitted 
sources form the basis of the point source emissions inventory that is

[[Page 34184]]

compiled annually.\39\ In addition, in compliance with the EPA's Air 
Emissions Reporting Requirements [80 FR 8787], Missouri develops a 
comprehensive emissions inventory of point, area, and mobile sources 
every 3 years. This triennial inventory compiled by the State is 
contained in the EPA's national emissions inventory (NEI) which is made 
publicly available every 3 years. For these reasons, the EPA is 
proposing to find that Missouri's maintenance plan meets the 
``Verification of Continued Attainment'' requirement.
---------------------------------------------------------------------------

    \38\ The EPA last determined that Missouri's SIP was sufficient 
to meet the requirements of section 110(a)(2)(E)(i) of the CAA on 
March 22, 2018 (83 FR 12496).
    \39\ This information is available to the EPA or members of the 
public upon request from the State of Missouri.
---------------------------------------------------------------------------

f. Contingency Measures in the Maintenance Plan
    Section 175A of the CAA requires that a maintenance plan include 
such contingency measures as the EPA deems necessary to assure that the 
State will promptly correct a violation of the NAAQS that occurs after 
redesignation. The maintenance plan should identify the contingency 
measures to be adopted, a schedule and procedure for adoption and 
implementation, and a time limit for action by the State. A State 
should also identify specific indicators to be used to determine when 
the contingency measures need to be implemented. The maintenance plan 
must also include a requirement that a State will implement all 
measures with respect to control of the pollutant that were contained 
in the SIP before redesignation of the area to attainment in accordance 
with section 175A(d).
    The contingency plan includes a triggering mechanism to determine 
when contingency measures are needed and a process of developing and 
implementing appropriate control measures. The triggering mechanisms 
contained in the maintenance plan and Consent Agreement are based on 
monitoring data from the Mott Street monitor and the industrial source 
monitors around the Ameren Rush Island facility. The EPA finds it 
appropriate to rely on monitoring data to trigger the contingency plan 
because the Mott Street monitor is being relied upon to demonstrate 
continued maintenance in the area as discussed in the Monitoring 
Network section of this document. Additionally, the industrial source 
monitors were sited consistent with relevant EPA guidance to capture 
maximum impacts from the Rush Island plant.\40\ Because the Rush Island 
plant is the largest remaining source in the maintenance area, the EPA 
agrees that monitoring around the Rush Island plant would be the best 
indicator of any potential future air quality issues in the maintenance 
area and thereby represents a reasonable triggering mechanism for the 
State's contingency plan.
---------------------------------------------------------------------------

    \40\ See Missouri's 2015 and 2016 annual monitoring network 
plans contained in the docket for this action for more information 
about the siting of the monitors around Rush Island.
---------------------------------------------------------------------------

    The State listed two types of triggers of its contingency plan. The 
first, a ``warning level response,'' will be triggered by a 99th 
percentile of daily maximum 1-hour average SO<INF>2</INF> 
concentrations greater than 79 ppb in a single calendar year in the 
Jefferson County maintenance area. The second, an ``action level 
response,'' will be triggered if a violation of the NAAQS is recorded 
in the Jefferson County maintenance area, specifically if the 3-year 
average of annual 99th percentile daily maximum 1-hour concentrations 
is 76 ppb or higher.
    If the warning level response is triggered, a study must be 
completed to determine whether the monitored SO<INF>2</INF> value 
indicates a trend toward higher concentrations in the Jefferson County 
maintenance area. The study will evaluate whether the trend, if any, is 
likely to continue. The study shall be completed as expeditiously as 
possible, but no later than 24 months after the State has determined 
that a warning level response has been triggered. It should be noted 
that the EPA does not require a State to implement contingency measures 
when occasional exceedances are recorded.
    If the action level response is triggered and is not found to be 
due to an exceptional event as defined at 40 CFR part 50.1(j), measures 
to address the violation shall be implemented as expeditiously as 
possible, but no later than 24 months after quality assured ambient 
data that has been entered into the AQS database indicating that this 
trigger has occurred. If a new measure or control is already 
promulgated and scheduled to be implemented at the federal or State 
level, and that measure or control is determined to be enough to 
address the upward trend in ambient SO<INF>2</INF> concentrations 
within the maintenance area, additional local measures may be 
unnecessary. Furthermore, Missouri will submit to the EPA an analysis 
demonstrating the proposed action level response measures are adequate 
to return the area to attainment. Contingency measures considered will 
be based on an analysis of the cause of the elevated ambient 
SO<INF>2</INF> concentrations from the entity(ies) likely to be 
contributing to the elevated concentrations. Measures may include 
improvements to existing control devices, addition of secondary control 
devices or improvements in housekeeping and maintenance, among other 
measures. It is not possible to develop a comprehensive list of 
contingency measures that can address all possible violations until the 
cause of the elevated concentrations is known. Any contingency measures 
implemented will require a compliance plan and expeditious compliance 
timeline from the entity(ies) involved. The EPA is proposing to find 
that Missouri's maintenance plan meets the ``Contingency Measures'' 
requirement.
    In addition to the contingency plan contained in the maintenance 
plan, the Consent Agreement contains specific contingency plan triggers 
and requirements for Ameren. Specifically, the Consent Agreement 
requires that Ameren perform an air quality analysis if any elevated 
monitoring values are recorded (one occurrence of a measured 
SO<INF>2</INF> concentration that exceeds 75 ppb for one hour) at any 
of the three industrial source monitors. Ameren must submit this air 
quality analysis including the monitored information and any relevant 
operational information to Missouri within a specified time frame.
    If through discussion of the air quality analysis, it is 
established that the elevated monitoring values were attributable to 
Ameren Rush Island, Ameren would provide the State with proposed 
potential mitigation measures, SO<INF>2</INF> emissions limitations, 
and a compliance schedule.
    The EPA proposes to conclude that the maintenance plan adequately 
addresses the five basic components of a maintenance plan: The 
attainment emissions inventory, maintenance demonstration, monitoring, 
verification of continued attainment, and a contingency plan. 
Therefore, the EPA proposes to find that the maintenance plan SIP 
revision submitted by Missouri for the Jefferson County 2010 
SO<INF>2</INF> nonattainment area meets the requirements of section 
175A of the CAA and proposes to approve the plan.

VI. What are the actions the EPA is proposing to take?

    The EPA is proposing to approve the maintenance plan for the 
Jefferson County 2010 SO<INF>2</INF> 1-hour NAAQS nonattainment area 
into the Missouri SIP (as compliant with CAA section 175A). The 
maintenance plan demonstrates that the area will continue to maintain 
the 2010 1-hour SO<INF>2</INF> NAAQS and includes a process to develop 
contingency measures to remedy any future violations of the 2010

[[Page 34185]]

1-hour SO<INF>2</INF> NAAQS and procedures for evaluation of potential 
violations.
    Additionally, the EPA is proposing to determine that the Jefferson 
County 2010 SO<INF>2</INF> 1-hour NAAQS nonattainment area has met the 
criteria under CAA section 107(d)(3)(E) for redesignation from 
nonattainment to attainment for the 2010 1-hour SO<INF>2</INF> NAAQS. 
On this basis, the EPA is proposing to approve Missouri's redesignation 
request for the area. Final approval of Missouri's redesignation 
request would change the legal designation of the portion of Jefferson 
County designated nonattainment at 40 CFR part 81 to attainment for the 
2010 1-hour SO<INF>2</INF> NAAQS.

VII. Environmental Justice Concerns

    When the EPA establishes a new or revised NAAQS, the CAA requires 
the EPA to designate all areas of the U.S. as either nonattainment, 
attainment, or unclassifiable. Area designations address environmental 
justice concerns by ensuring that the public is properly informed about 
the air quality in an area. If an area is designated in nonattainment 
of the NAAQS, the CAA provides for the EPA to redesignate the area to 
attainment upon a demonstration by the state authority that air quality 
is attaining the NAAQS and will continue to maintain the NAAQS in order 
to ensure that all those residing, working, attending school, or 
otherwise present in those areas are protected, regardless of minority 
and economic status.

VIII. Incorporation by Reference

    In this document, the EPA is proposing to amend regulatory text 
that includes incorporation by reference. In accordance with the 
requirements of 1 CFR 51.5, the EPA is proposing to incorporate by 
reference the Missouri State Implementation Plan described in the 
proposed amendments to 40 CFR part 52 set forth below. The EPA has 
made, and will continue to make, these materials generally available 
through www.regulations.gov and at the EPA Region 7 Office (please 
contact the person identified in the FOR FURTHER INFORMATION CONTACT 
section of this preamble for more information).

IX. Statutory and Executive Order Reviews

    Under the Clean Air Act (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, if they meet the criteria of the CAA. Accordingly, this 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 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) and 13563 (76 FR 3821, January 21, 2011);
    <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 an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
    <bullet> Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
    <bullet> Is not subject to requirements of the National Technology 
Transfer and Advancement Act (NTTA) because this rulemaking does not 
involve technical standards; and
    <bullet> This action does not have disproportionately high and 
adverse human health or environmental effects on minority populations, 
low-income populations and/or indigenous peoples, as specified in 
Executive Order 12898 (59 FR 7629, February 16, 1994). The analysis for 
this determination is contained in Section VII of this action, 
``Environmental Justice Concerns.''
    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 
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

40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Maintenance plan, Redesignation, Sulfur oxides.

40 CFR Part 81

    Environmental protection, Air pollution control, Designations, 
Redesignation, Intergovernmental relations, Reporting and recordkeeping 
requirements, Sulfur oxides.

    Dated: June 22, 2021.
Edward H. Chu,
Acting Regional Administrator, Region 7.

    For the reasons stated in the preamble, the EPA proposes to amend 
40 CFR parts 52 and 81 as set forth below:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

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

Subpart AA--Missouri

0
2. In Sec.  52.1320:
0
a. The table in paragraph (d) is amended by adding the entry ``(34)'' 
in numerical order.
0
b. The table in paragraph (e) is amended by adding the entry ``(79)'' 
in numerical order.
    The additions read as follows:


Sec.  52.1320  Identification of plan.

* * * * *
    (d) * * *

[[Page 34186]]



                            EPA-Approved Missouri Source-Specific Permits and Orders
----------------------------------------------------------------------------------------------------------------
                                                             State
          Name of source             Order/permit No.   effective date   EPA approval date       Explanation
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
(34) Ameren Missouri.............  Consent Agreement        12/14/2020  [Date of             ...................
                                    and Addendum No.                     publication of the
                                    APCP-2015-034.                       final rule in the
                                                                         Federal Register],
                                                                         [Federal Register
                                                                         citation of the
                                                                         final rule].
----------------------------------------------------------------------------------------------------------------

    (e) * * *

                               EPA-Approved Missouri Nonregulatory SIP Provisions
----------------------------------------------------------------------------------------------------------------
   Name of nonregulatory SIP     Applicable  geographic or   State submittal    EPA approval
           revision                 nonattainment area            date              date           Explanation
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
(79) Jefferson County 1-hour    Jefferson County            12/27/17; 5/15/   [Date of          This action
 SO2 NAAQS Maintenance Plan                                  18; 2/7/19; 2/    publication of    approves the
 and Supplemental Modeling                                   25/19; and 4/9/   the final rule    Maintenance
 Analyses.                                                   21                in the Federal    Plan and the
                                                                               Register],        Supplemental
                                                                               [Federal          Modeling
                                                                               Register          Analyses for
                                                                               citation of the   the Jefferson
                                                                               final rule]       County area.
----------------------------------------------------------------------------------------------------------------

0
3. In Sec.  52.1343, add paragraph (c) to read as follows:


Sec.  52.1343  Control strategy: Sulfur dioxide.

* * * * *
    (c) Redesignation to attainment. EPA has determined, as of [date of 
publication of the final rule in the Federal Register], that the 
Jefferson County 2010 SO<INF>2</INF> nonattainment area is redesignated 
to attainment of the 2010 SO<INF>2</INF> 1-hour National Ambient Air 
Quality Standard (NAAQS) in accordance with the requirements of Clean 
Air Act (CAA) section 107(d)(3) and has approved its maintenance plan 
and supplemental modeling demonstration analyses as meeting the 
requirements of CAA section 175A.

PART 81--DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES

0
4. The authority citation for part 81 continues to read as follows:

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

Subpart C--Section 107 Attainment Status Designations

0
5. In Sec.  81.326, revise the entry ``Jefferson County, MO'' in the 
table entitled ``Missouri--2010 Sulfur Dioxide NAAQS [Primary]'' to 
read as follows:


Sec.  81.326  Missouri.

* * * * *

                   Missouri--2010 Sulfur Dioxide NAAQS
                                [Primary]
------------------------------------------------------------------------
                                               Designation
       Designated area 1        ----------------------------------------
                                       Date 2               Type
------------------------------------------------------------------------
 
                              * * * * * * *
Jefferson County, MO             [Date 30 days      Attainment.
                                  after date of
                                  publication of
                                  the final rule
                                  in the Federal
                                  Register]
    Jefferson County (part):...
        That portion within
         Jefferson County
         described by
         connecting the
         following four sets of
         UTM coordinates moving
         in a clockwise manner:
            (Herculaneum USGS
             Quadrangle)
             718360.283
             4250477.056,
             729301.869
             4250718.415,
             729704.134
             4236840.30,
             718762.547
             4236558.715.
            (Festus USGS
             Quadrangle)
             718762.547
             4236558.715,
             729704.134
             4236840.30,
             730066.171
             4223042.637,
             719124.585
             4222680.6.
            (Selma USGS
             Quadrangle)
             729704.134
             4236840.30,
             730428.209
             4236840.3,
             741047.984
             4223283.996,
             730066.171
             4223042.637.
            (Valmeyer USGS
             Quadrangle)
             729301.869
             4250718.415,
             731474.096
             4250798.868,
             730428.209
             4236840.3,
             729704.134
             4236840.30.
 
                              * * * * * * *
------------------------------------------------------------------------
\1\ Includes any Indian country in each county or area, unless otherwise
  specified. EPA is not determining the boundaries of any area of Indian
  country in this table, including any area of Indian country located in
  the larger designation area. The inclusion of any Indian country in
  the designation area is not a determination that the state has
  regulatory authority under the Clean Air Act for such Indian country.
\2\ This date is April 9, 2018, unless otherwise noted.


[[Page 34187]]

* * * * *
[FR Doc. 2021-13693 Filed 6-28-21; 8:45 am]
BILLING CODE 6560-50-P


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