[Federal Register Volume 84, Number 250 (Tuesday, December 31, 2019)]
[Proposed Rules]
[Pages 72278-72289]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-28236]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R04-OAR-2018-0792; FRL-10003-83-Region 4]


Air Plan Approval; Alabama; 2010 1-Hour SO2 NAAQS Transport 
Infrastructure

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve Alabama's August 20, 2018, State Implementation Plan (SIP) 
submission pertaining to the ``good neighbor'' provision of the Clean 
Air Act (CAA or Act) for the 2010 1-hour sulfur dioxide 
(SO2) National Ambient Air Quality Standard (NAAQS). The 
good neighbor provision requires each state's implementation plan to 
address the interstate transport of air pollution in amounts that 
contribute significantly to nonattainment, or interfere with 
maintenance, of a NAAQS in any other state. In this action, EPA is 
proposing to determine that Alabama will not contribute significantly 
to nonattainment or interfere with maintenance of the 2010 1-hour 
SO2 NAAQS in any other state. Therefore, EPA is proposing to 
approve the August 20, 2018, SIP revision as meeting the requirements 
of the good neighbor provision for the 2010 1-hour SO2 
NAAQS.

DATES: Written comments must be received on or before January 30, 2020.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2018-0792 at http://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from Regulations.gov. 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. 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, the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit http://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Michele Notarianni, Air Regulatory 
Management Section, Air Planning and Implementation Branch, Air and 
Radiation Division, U.S. Environmental Protection Agency, Region 4, 61 
Forsyth Street SW, Atlanta, Georgia 30303-8960. Ms. Notarianni can be 
reached via phone number (404) 562-9031 or via electronic mail at 
notarianni.michele@epa.gov.

SUPPLEMENTARY INFORMATION:

I. Background

A. Infrastructure SIPs

    On June 2, 2010, EPA promulgated a revised primary SO2 
NAAQS with a level of 75 parts per billion (ppb), based on a 3-year 
average of the annual 99th percentile of 1-hour daily maximum 
concentrations. See 75 FR 35520 (June 22, 2010). Whenever EPA 
promulgates a new or revised NAAQS, CAA section 110(a)(1) requires 
states to make SIP

[[Page 72279]]

submissions to provide for the implementation, maintenance, and 
enforcement of the NAAQS. This particular type of SIP submission is 
commonly referred to as an ``infrastructure SIP.'' These submissions 
must meet the various requirements of CAA section 110(a)(2), as 
applicable.
    Section 110(a)(2)(D)(i)(I) of the CAA requires SIPs to include 
provisions prohibiting any source or other type of emissions activity 
in one state from emitting any air pollutant in amounts that will 
contribute significantly to nonattainment, or interfere with 
maintenance, of the NAAQS in another state. The two clauses of this 
section are referred to as prong 1 (significant contribution to 
nonattainment) and prong 2 (interference with maintenance of the 
NAAQS).
    In a letter dated August 20, 2018,\1\ the Alabama Department of 
Environmental Management (ADEM) submitted a revision to the Alabama SIP 
only addressing prongs 1 and 2 of CAA section 110(a)(2)(D)(i)(I) for 
the 2010 1-hour SO2 NAAQS.\2\ EPA is proposing to approve 
ADEM's August 20, 2018, SIP submission because the State demonstrated 
that Alabama will not contribute significantly to nonattainment, or 
interfere with maintenance, of the 2010 1-hour SO2 NAAQS in 
any other state. All other elements related to the infrastructure 
requirements of section 110(a)(2) for the 2010 1-hour SO2 
NAAQS for Alabama have been addressed in separate rulemakings.\3\
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    \1\ EPA received ADEM's August 20, 2018, SIP submission on 
August 27, 2018.
    \2\ On April 23, 2013, and October 24, 2017, ADEM submitted SIP 
revisions addressing all infrastructure elements with respect to the 
2010 1-hour SO2 NAAQS with the exception of prongs 1 and 
2 of CAA section 110(a)(2)(D)(i)(I).
    \3\ EPA acted on all other infrastructure elements for the 2010 
1-hour SO2 NAAQS in Alabama's April 23, 2013, and October 
24, 2017, SIP revisions on January 12, 2017 (82 FR 3637), October 
12, 2017 (82 FR 47393), and July 6, 2018 (83 FR 31454).
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B. 2010 1-Hour SO2 NAAQS Designations Background

    In this action, EPA has considered information from the 2010 1-hour 
SO2 NAAQS designations process, as discussed in more detail 
in section III.C of this notice. For this reason, a brief summary of 
EPA's designations process for the 2010 1-hour SO2 NAAQS is 
included here.\4\
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    \4\ While designations may provide useful information for 
purposes of analyzing transport, particularly for a more source-
specific pollutant such as SO2, EPA notes that 
designations themselves are not dispositive of whether or not upwind 
emissions are impacting areas in downwind states. EPA has 
consistently taken the position that as to impacts, CAA section 
110(a)(2)(D) refers only to prevention of ``nonattainment'' in other 
states, not to prevention of nonattainment in designated 
nonattainment areas or any similar formulation requiring that 
designations for downwind nonattainment areas must first have 
occurred. See e.g., Clean Air Interstate Rule, 70 FR 25162, 25265 
(May 12, 2005); Cross-State Air Pollution Rule, 76 FR 48208, 48211 
(August 8, 2011); Final Response to Petition from New Jersey 
Regarding SO2 Emissions From the Portland Generating 
Station, 76 FR 69052 (November 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 SO2 NAAQS prior to issuance of 
designations for that standard).
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    After the promulgation of a new or revised NAAQS, EPA is required 
to designate areas as ``nonattainment,'' ``attainment,'' or 
``unclassifiable'' pursuant to section 107(d)(1) of the CAA. The 
process for designating areas following promulgation of a new or 
revised NAAQS is contained in section 107(d) of the CAA. The CAA 
requires EPA to complete the initial designations process within two 
years of promulgating a new or revised standard. If the Administrator 
has insufficient information to make these designations by that 
deadline, EPA has the authority to extend the deadline for completing 
designations by up to one year.
    EPA promulgated the 2010 1-hour SO2 NAAQS on June 2, 
2010. See 75 FR 35520 (June 22, 2010). EPA completed the first round of 
designations (``round 1'') \5\ for the 2010 1-hour SO2 NAAQS 
on July 25, 2013, designating 29 areas in 16 states as nonattainment 
for the 2010 1-hour SO2 NAAQS. See 78 FR 47191 (August 5, 
2013). EPA signed Federal Register notices of promulgation for round 2 
designations \6\ on June 30, 2016 (81 FR 45039 (July 12, 2016)) and on 
November 29, 2016 (81 FR 89870 (December 13, 2016)), and round 3 
designations \7\ on December 21, 2017 (83 FR 1098 (January 9, 
2018)).\8\
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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 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 
SO2 designations at https://www.epa.gov/sulfur-dioxide-designations.
    \7\ 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 
SO2 designations at https://www.epa.gov/sulfur-dioxide-designations.
    \8\ Consent Decree, Sierra Club v. McCarthy, Case No. 3:13-cv-
3953-SI (N.D. Cal. Mar. 2, 2015). This consent decree requires EPA 
to sign for publication in the Federal Register notices of the 
Agency's promulgation of area designations for the 2010 1-hour 
SO2 NAAQS by three specific deadlines: July 2, 2016 
(``round 2''); December 31, 2017 (``round 3''); and December 31, 
2020 (``round 4'').
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    On August 21, 2015 (80 FR 51052), EPA separately promulgated air 
quality characterization requirements for the 2010 1-hour 
SO2 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 2,000 tons per year (tpy) or more of SO2, 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 SO2 
emissions to less than 2,000 tpy, or provide documentation that the 
sources have been shut down. EPA expected that the information 
generated by implementation of the DRR would help inform designations 
for the 2010 1-hour SO2 NAAQS that must be completed by 
December 31, 2020 (``round 4'').
    For Alabama, EPA designated all counties as attainment/
unclassifiable or unclassifiable in round 3 except for a portion of 
Shelby County around the Lhoist North America of Alabama--Montevallo 
Plant (LNA--Montevallo) that is currently conducting monitoring to 
inform round 4 designations.\9\ There are no nonattainment areas in 
Alabama for the 2010 1-hour SO2 NAAQS based on rounds 1, 2, 
and 3 of EPA's designations process.\10\
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    \9\ See Technical Support Document: Chapter 3 Final Round 3 Area 
Designations for the 2010 1-Hour SO2 Primary National Ambient Air 
Quality Standard for Alabama at https://www.epa.gov/sites/production/files/2017-12/documents/03-al-so2-rd3-final.pdf.
    \10\ On August 5, 2013 (78 FR 47191) and effective October 4, 
2013, EPA designated 29 areas in 16 states as nonattainment for the 
2010 1-hour SO2 NAAQS based on violating monitors using 
air quality data for the years 2009-2011, but did not, at that time, 
designate other areas in the country. On July 12, 2016 (81 FR 
45039), effective September 12, 2016, and December 13, 2016 (81 FR 
89870), effective January 12, 2017, EPA published a final rule 
establishing air quality designations for 65 areas in 24 states for 
the 2010 SO2 NAAQS including seven nonattainment areas, 
41 attainment/unclassifiable areas, and 17 unclassifiable areas. On 
January 9, 2018 (83 FR 1098) effective April 9, 2018, EPA designated 
six areas as nonattainment; 23 areas designated unclassifiable; and 
the rest of the areas covered by this round in all states, 
territories, and tribal lands were designated attainment/
unclassifiable. No areas in Alabama were designated as nonattainment 
in these actions. See https://www.epa.gov/sulfur-dioxide-designations/sulfur-dioxide-designations-regulatory-actions.
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II. Relevant Factors Used To Evaluate the 2010 1-Hour SO2 
Interstate Transport SIPs

    Although SO2 is emitted from a similar universe of point 
and nonpoint sources as is directly emitted fine particulate matter 
(PM2.5) and the precursors to ozone and PM2.5, 
interstate transport of SO2 is unlike the transport of 
PM2.5 or ozone because SO2 emissions

[[Page 72280]]

sources usually do not have long range SO2 impacts. The 
transport of SO2 relative to the 2010 1-hour SO2 
NAAQS is more analogous to the transport of lead (Pb) relative to the 
Pb NAAQS in that emissions of SO2 typically result in 1-hour 
pollutant impacts of possible concern only near the emissions source. 
However, ambient 1-hour concentrations of SO2 do not 
decrease as quickly with distance from the source as do 3-month average 
concentrations of Pb, because SO2 gas is not removed by 
deposition as rapidly as are Pb particles and because SO2 
typically has a higher emissions release height than Pb. Emitted 
SO2 has wider ranging impacts than emitted Pb, but it does 
not have such wide-ranging impacts that treatment in a manner similar 
to ozone or PM2.5 would be appropriate. Accordingly, while 
the approaches that the EPA has adopted for ozone or PM2.5 
transport are too regionally focused, the approach for Pb transport is 
too tightly circumscribed to the source. SO2 transport is 
therefore a unique case and requires a different approach.
    In SO2 transport analyses, EPA focuses on a 50 km-wide 
zone because the physical properties of SO2 result in 
relatively localized pollutant impacts near an emissions source that 
drop off with distance. Given the properties of SO2, EPA 
selected a spatial scale with dimensions from four to 50 kilometers 
(km) from point sources--the ``urban scale''--to assess trends in area-
wide air quality that might impact downwind states.\11\ As discussed 
further in section III.B, EPA selected the urban scale as appropriate 
for assessing trends in both area-wide air quality and the 
effectiveness of large-scale pollution control strategies at 
SO2 point sources. EPA's selection of this transport 
distance for SO2 is consistent with 40 CFR 58, Appendix D, 
Section 4.4.4(4) ``Urban scale,'' which states that measurements in 
this scale would be used to estimate SO2 concentrations over 
large portions of an urban area with dimensions from four to 50 km. The 
American Meteorological Society/Environmental Protection Agency 
Regulatory Model (AERMOD) is EPA's preferred modeling platform for 
regulatory purposes for near-field dispersion of emissions for 
distances up to 50 km. See Appendix W of 40 CFR part 51. Thus, EPA 
applied the 50-km threshold as a reasonable distance to evaluate 
emission source impacts into neighboring states and to assess air 
quality monitors within 50 km of the State's border, which is discussed 
further in section III.C.
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    \11\ For the definition of spatial scales for SO2, 
see 40 CFR part 58, Appendix D, section 4.4 (``Sulfur Dioxide 
(SO2) Design Criteria''). For further discussion on how 
EPA applies these definitions with respect to interstate transport 
of SO2, see EPA's proposed rulemaking on Connecticut's 
SO2 transport SIP. See 82 FR 21351, 21352, 21354 (May 8, 
2017).
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    As discussed in sections III.C and III.D, EPA first reviewed 
Alabama's analysis to assess how the State evaluated the transport of 
SO2 to other states, the types of information used in the 
analysis, and the conclusions drawn by the State. EPA then conducted a 
weight of evidence analysis based on a review of the State's submission 
and other available information, including SO2 air quality 
and available source modeling for other states' sources within 50 km of 
the Alabama border.\12\
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    \12\ This proposed approval action is based on the information 
contained in the administrative record for this action and does not 
prejudge any other future EPA action that may make other 
determinations regarding Alabama's air quality status. Any such 
future actions, such as area designations under any NAAQS, will be 
based on their own administrative records and EPA's analyses of 
information that become available at those times. Future available 
information may include, and is not limited to, monitoring data and 
modeling analyses conducted pursuant to the DRR and information 
submitted to EPA by states, air agencies, and third-party 
stakeholders such as citizen groups and industry representatives.
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III. Alabama's SIP Submission and EPA's Analysis

A. State Submission

    Through a letter dated August 20, 2018, ADEM submitted a revision 
to the Alabama SIP addressing prongs 1 and 2 of CAA section 
110(a)(2)(D)(i)(I) for the 2010 1-hour SO2 NAAQS.\13\ 
Alabama conducted a weight of evidence analysis to examine whether 
SO2 emissions from the State adversely affect attainment or 
maintenance of the 2010 1-hour SO2 NAAQS in downwind states.
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    \13\ On September 5, 2019, September 20, 2019, September 25, 
2019, December 2, 2019, and December 6, 2019, ADEM provided 
supplemental information pertaining to Escambia Operating Company--
Big Escambia Creek Plant's (Big Escambia's) DRR modeling that 
addresses and resolves the issues with the original modeling for 
this source performed under the DRR (collectively, the ``Big 
Escambia Supplement''). See Section III.C.1.b. for more information. 
Big Escambia is located in Escambia County, Alabama.
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    ADEM based its conclusions for prongs 1 and 2 on attaining 2015-
2017 SO2 design values (DVs) \14\ in Alabama and adjacent 
states; the lack of 2010 1-hour SO2 NAAQS nonattainment 
areas in Alabama or within close proximity to Alabama; the existence of 
DRR modeling for Alabama SO2 sources; and established 
federal and State control measures which address SO2 
emissions. EPA's evaluation of Alabama's August 20, 2018, SIP 
submission is detailed in sections III.B, C, and D.
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    \14\ A ``Design Value'' is a statistic that describes the air 
quality status of a given location relative to the level of the 
NAAQS. The DV for the primary 2010 1-hour SO2 NAAQS is 
the 3-year average of annual 99th percentile daily maximum 1-hour 
values for a monitoring site. For example, the 2017 DV is calculated 
based on the three-year average from 2015-2017. The interpretation 
of the primary 2010 1-hour SO2 NAAQS including the data 
handling conventions and calculations necessary for determining 
compliance with the NAAQS can be found in Appendix T to 40 CFR part 
50.
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B. EPA's Evaluation Methodology

    EPA believes that a reasonable starting point for determining which 
sources and emissions activities in Alabama are likely to impact 
downwind air quality in other states with respect to the 2010 1-hour 
SO2 NAAQS is by using information in EPA's National 
Emissions Inventory (NEI).\15\ 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, 
that is updated every three years using information provided by the 
states and other information available to EPA. EPA evaluated data from 
the 2014 NEI (version 2), the most recently available, complete, and 
quality assured dataset of the NEI.
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    \15\ EPA's NEI is available at https://www.epa.gov/air-emissions-inventories/national-emissions-inventory.
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    As shown in Table 1, the majority of SO2 emissions in 
Alabama originate from point sources.\16\ In 2014, the total 
SO2 emissions from point sources in Alabama comprised 
approximately 96 percent of the total SO2 emissions in the 
State. Further analysis of these data show that SO2 
emissions from fuel combustion from point sources make up approximately 
74 percent of the total SO2 emissions in the State. Because 
emissions from the other listed source categories are more dispersed 
throughout the State, those categories are less likely to cause high 
ambient concentrations when compared to a point source on a ton-for-ton 
basis. Based on EPA's analysis of the 2014 NEI, EPA believes that it is 
appropriate to focus the analysis on SO2 emissions from 
Alabama's larger point sources (i.e., emitting over 100 tpy of 
SO2 in 2017), which are located within the ``urban scale,'' 
i.e., within 50 km of one or more state borders.
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    \16\ Alabama's point sources listed in Table 1, for the purposes 
of this action, are comprised of all of the ``Fuel Combustion'' 
categories and ``Industrial Processes (All Categories),'' with the 
exception of residential fuel consumption. Residential fuel 
combustion is considered a nonpoint source and, thus, residential 
fuel combustion data is not included in the point source fuel 
combustion data and related calculations.

[[Page 72281]]



 Table 1--Summary of 2014 NEI (Version 2) SO2 Data for Alabama by Source
                                  Types
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                                                            Percent of
                Category                     Emissions       total SO2
                                               (tpy)         emissions
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Fuel Combustion: Electric Generating          119,922.45              60
 Units (EGUs) (All Fuel Types)..........
Fuel Combustion: Industrial Boilers/           27,658.08              14
 Internal Combustion Engines (All Fuel
 Types).................................
Fuel Combustion: Commercial/                       13.58               0
 Institutional (All Fuel Types).........
Fuel Combustion: Residential (All Fuel             84.40               0
 Types).................................
Industrial Processes (All Categories)...       43,805.93              22
Mobile Sources (All Categories).........        1,528.60               1
Fires (All Types).......................        7,585.65               4
Waste Disposal..........................          814.84               0
Solvent Processes.......................            0.62               0
Miscellaneous (Non-Industrial, Gas                  3.67               0
 Stations)..............................
                                         -------------------------------
    SO2 Emissions Total.................      201,417.82             100
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    As explained in Section II, because the physical properties of 
SO2 result in relatively localized pollutant impacts near an 
emissions source that drop off with distance, in SO2 
transport analyses, EPA focuses on a 50 km-wide zone. Thus, EPA focused 
its evaluation on Alabama's point sources of SO2 emissions 
located within approximately 50 km of another state and their potential 
impact on neighboring states.
    As discussed in section I.B., EPA's current implementation strategy 
for the 2010 1-hour SO2 NAAQS includes the flexibility to 
characterize air quality for stationary sources subject to the DRR via 
either data collected at ambient air quality monitors sited to capture 
the points of maximum concentration, or air dispersion modeling 
(hereinafter referred to as ``DRR monitors'' or ``DRR modeling,'' 
respectively). EPA's assessment of SO2 emissions from 
Alabama's point sources located within approximately 50 km of another 
state and their potential impacts on neighboring states (see sections 
III.C.1. and II.C.2 of this notice) and SO2 air quality data 
at monitors within 50 km of the Alabama border (see section III.C.3. of 
this notice) is informed by all available data at the time of this 
proposed rulemaking.\17\
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    \17\ EPA notes that the evaluation of other states' satisfaction 
of section 110(a)(2)(D)(i)(I) for the 2010 1-hour SO2 
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 Alabama, depending on available 
information and state-specific circumstances.
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    As described in Section III, EPA proposes to conclude that an 
assessment of Alabama's satisfaction of the prong 1 and 2 requirements 
under section 110(a)(2)(D)(i)(I) of the CAA for the 2010 1-hour 
SO2 NAAQS may be reasonably based upon evaluating the 
downwind impacts via modeling and an assessment of SO2 
emissions from Alabama's point sources emitting more than 100 tpy of 
SO2 (including fuel combustion sources) that are located 
within approximately 50 km of another state and upon any regulations 
intended to address Alabama's SO2 point sources.

C. EPA's Prong 1 Evaluation--Significant Contribution to Nonattainment

    Prong 1 of the good neighbor provision requires states' plans to 
prohibit emissions that will contribute significantly to nonattainment 
of a NAAQS in another state. ADEM states in its submission that Alabama 
does not contribute significantly to nonattainment of the 2010 1-hour 
SO2 NAAQS in another state based on the information provided 
therein. To evaluate Alabama's satisfaction of prong 1, EPA assessed 
Alabama's SIP submission with respect to the following factors: (1) 
Potential ambient air quality impacts of SO2 emissions from 
certain facilities in Alabama on neighboring states based on available 
air dispersion modeling results; (2) SO2 emissions from 
Alabama sources; (3) SO2 ambient air quality for Alabama and 
neighboring states; (4) SIP-approved Alabama regulations that address 
SO2 emissions; and (5) federal regulations that reduce 
SO2 emissions at Alabama sources. A detailed discussion of 
Alabama's SIP submission with respect to each of these factors follows. 
EPA proposes that these factors, taken together, support the Agency's 
proposed determination that Alabama will not contribute significantly 
to nonattainment of the 2010 1-hour SO2 NAAQS in another 
state. EPA's proposed conclusion is based, in part, on the fact that 
adjacent states with modeled DRR sources located within 50 km of the 
Alabama border do not have areas that are violating or that model 
violations of the 2010 1-hour SO2 NAAQS and the fact that 
the valid SO2 2016-2018 DVs for monitors in adjacent states 
show attainment of the 2010 1-hour SO2 NAAQS.\18\ Also, 2017 
SO2 emissions for Alabama's non-DRR sources emitting over 
100 tons of SO2 within 50 km of another state are at 
distances or emit levels of SO2 that make it unlikely that 
these SO2 emissions could interact with SO2 
emissions from the neighboring states' sources in such a way as to 
contribute significantly to nonattainment in these neighboring states. 
In addition, the downward trends in statewide SO2 emissions, 
combined with federal and SIP-approved State regulations affecting 
SO2 emissions from Alabama's sources, further support EPA's 
proposed conclusion.
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    \18\ The Floyd County, Georgia monitor (AQS ID: 13-115-0003) 
does not have a valid DV for the 2015-2017 and 2016-2018 time 
periods. This monitor has valid DVs for the 2010-2012 through 2014-
2016 time periods which declined over this period and are all below 
the level of the 2010 1-hour SO2 NAAQS.
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1. SO2 Designations Air Dispersion Modeling
a. State Submission

[[Page 72282]]

    In its August 20, 2018, SIP submission, ADEM referenced a January 
14, 2016, letter \19\ that the State submitted to EPA identifying the 
facilities in Alabama with SO2 emissions subject to the 
DRR.\20\ ADEM explained that the DRR modeling data is contained in 
EPA's technical support document (TSD) for the SO2 round 3 
area designations.\21\
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    \19\ Alabama's January 14, 2016, letter is available on 
www.regulations.gov at Docket ID No. EPA-HQ-OAR-2017-0003.
    \20\ In 2017, Alabama provided recommendations and submitted air 
dispersion modeling for the 2010 1-hour SO2 NAAQS for the 
DRR sources in the State which elected to comply with the DRR using 
modeling. The remainder of Alabama's DRR sources established 
federally-enforceable limits, shut down, or the State installed and 
began operation of new, approved SO2 monitors to 
characterize SO2 air quality around the source. See 
https://www.epa.gov/so2-pollution/so2-data-requirements-rule-january-13-2017-state-submittals-alabama.
    \21\ See Technical Support Document: Chapter 3 Final Round 3 
Area Designations for the 2010 1-Hour SO2 Primary National Ambient 
Air Quality Standard for Alabama at https://www.epa.gov/sites/production/files/2017-12/documents/03-al-so2-rd3-final.pdf. See also 
Technical Support Document: Chapter 3 Proposed Round 3 Area 
Designations for the 2010 1-Hour SO2 Primary National Ambient Air 
Quality Standard for Alabama at https://www.epa.gov/sites/production/files/2017-08/documents/3_al_so2_rd3-final.pdf.
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b. EPA Analysis
    EPA evaluated available DRR modeling data for sources in Alabama 
within 50 km of another state, including the Big Escambia Supplement, 
and available DRR modeling data for sources in the adjacent states of 
Florida, Georgia, Mississippi, and Tennessee that are within 50 km of 
the Alabama border.\22\ The purpose of evaluating DRR modeling results 
in adjacent states within 50 km of the Alabama border is to ascertain 
whether any nearby sources in Alabama are impacting a violation of the 
2010 1-hour SO2 NAAQS in another state.
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    \22\ As discussed in section I.B., Alabama used air dispersion 
modeling to characterize air quality in the vicinity of certain 
SO2 emitting sources to identify the maximum 1-hour 
SO2 concentrations in ambient air which informed EPA's 
round 3 SO2 designations. EPA's preferred modeling 
platform for regulatory purposes is AERMOD (Appendix W of 40 CFR 
part 51). In these DRR modeling analyses using AERMOD, the impacts 
of the actual emissions for one or more of the recent 3-year periods 
(e.g., 2012-2014, 2013-2015, 2014-2016) were considered, and in some 
cases, the modeling was of currently effective limits on allowable 
emissions in lieu of or as a supplement to modeling of actual 
emissions. The available air dispersion modeling of certain 
SO2 sources can support transport related conclusions 
about whether sources in one state are potentially contributing 
significantly to nonattainment or interfering with maintenance of 
the 2010 1-hour SO2 standard in other states. While 
AERMOD was not designed specifically to address interstate 
transport, the 50-km distance that EPA recommends for use with 
AERMOD aligns with the concept that there are localized pollutant 
impacts of SO2 near an emissions source that drop off 
with distance. Thus, EPA believes that the use of AERMOD provides a 
reliable indication of air quality for transport purposes.
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    Of the 15 sources in Alabama initially subject to the DRR, 10 
sources conducted dispersion modeling.\23\ Six of the 10 modeled 
sources are within 50 km of another state: Akzo Nobel Functional 
Chemicals--Lemoyne Site (AkzoNobel); Alabama Power Company--James M. 
Barry Electric Generating Plant (Plant Barry); Ascend Performance 
Materials--Decatur Plant (Ascend); Big Escambia; PowerSouth Energy 
Cooperative--Charles R. Lowman Power Plant (Lowman); and Continental 
Carbon Company--Phenix City Plant (Continental Carbon).\24\ With 
respect to Continental Carbon, EPA previously determined that the 
modeling and supporting information provided to meet DRR requirements 
was acceptable.\25\ With respect to the modeling and other information 
submitted by the State for the remaining five modeled Alabama sources 
within 50 km of another state (i.e., AkzoNobel, Ascend, Big Escambia, 
Lowman, and Plant Barry), EPA previously determined that the Agency 
does not have sufficient information to demonstrate whether the areas 
around these sources meet or do not meet the 2010 1-hour SO2 
NAAQS or contribute to an area that does not meet the standard, and 
thus designated these areas as unclassifiable.\26\ Although EPA does 
not have any indications that there are violations of the 2010 1-hour 
SO2 NAAQS in these areas, the Agency assessed AkzoNobel, 
Ascend, Lowman, and Plant Barry in section III.C.2.b. of this proposed 
action with respect to interstate transport for the 2010 1-hour 
SO2 NAAQS. Regarding Big Escambia, ADEM provided 
supplemental information in September and December of 2019 that 
addresses the issues with the original modeling for this source 
performed under the DRR for the purposes of evaluating interstate 
transport of SO2 from Alabama into Florida.\27\ EPA's TSD 
for Big Escambia summarizes the issues with the original DRR modeling 
and how ADEM has now addressed these issues for the purpose of 
evaluating potential ambient air impacts in the neighboring state of 
Florida.\28\ Table 2 provides a summary of the 99th percentile daily 
maximum 1-hour average concentrations estimated by the modeling for Big 
Escambia and Continental Carbon, which are based on actual emissions 
for Big Escambia and potential to emit (PTE) emissions for Continental 
Carbon. Alabama's modeling analyses for Big Escambia and Continental 
Carbon indicate that the maximum impacts did not exceed the level of 
the 2010 1-hour SO2 NAAQS in neighboring states. Based on 
the modeling results indicating that the maximum impacts did not exceed 
the level of the 2010 1-hour SO2 NAAQS in neighboring 
states, no further analysis is necessary for assessing the potential 
impacts of the interstate transport of SO2 emissions from 
these facilities.
---------------------------------------------------------------------------

    \23\ Of the remaining five sources in Alabama initially subject 
to the DRR which did not opt to conduct dispersion modeling, three 
sources accepted federally-enforceable permit limits to exempt out 
of the DRR requirements, one source provided documentation that the 
facility shut down, and one source installed a monitor. The three 
sources that accepted federally-enforceable permit limits to exempt 
out of the DRR requirements are: Alabama Power--Gadsden Electric 
Generating Plant; Alabama Power--Greene County Electric Generating 
Plant; and Tennessee Valley Authority (TVA)--Colbert Fossil Plant. 
Alabama's one DRR source which shut down is the TVA--Widows Creek 
Fossil Plant. As mentioned in Section I.B., LNA--Montevallo 
installed a monitor to inform round 4 designations. See Docket ID 
No. EPA-HQ-OAR-2017-0003.
    \24\ The Mobile County area includes two DRR sources: AkzoNobel 
and Plant Barry. Due to the close proximity of AkzoNobel and Plant 
Barry to each other, a combined air dispersion modeling analysis was 
conducted for both facilities pursuant to the DRR.
    \25\ See https://www.epa.gov/sites/production/files/2017-08/documents/3_al_so2_rd3-final.pdf.
    \26\ See EPA's initial and final TSDs for Alabama at: https://www.epa.gov/sites/production/files/2017-08/documents/3_al_so2_rd3-final.pdf and https://www.epa.gov/sites/production/files/2017-12/documents/03-al-so2-rd3-final.pdf.
    \27\ ADEM submitted the Big Escambia Supplement to EPA in 
separate correspondence dated September 5, 2019, September 20, 2019, 
September 25, 2019, December 2, 2019, and December 6, 2019, and it 
is included in the docket for this proposed action, with the 
exception of certain files due to their nature and size and 
incompatibility with the Federal Docket Management System. These 
files are available at the EPA Region 4 office for review. To 
request these files, please contact the person listed in this notice 
under the section titled FOR FURTHER INFORMATION CONTACT.
    \28\ EPA's TSD addressing Big Escambia for this proposed 
rulemaking is located in the docket.

[[Page 72283]]



                               Table 2--Alabama Sources With Valid \29\ DRR Modeling Located Within 50 km of Another State
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                 Modeled 99th
                                                                                                               percentile daily
                                                              Approximate distance                            maximum 1-hour SO2
             DRR source                      County              from source to         Other facilities       concentration in      Model grid extends
                                                               adjacent State (km)    included in modeling   nearest neighboring    into another State?
                                                                                                                 state (ppb)
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
Big Escambia.......................  Escambia..............  8 (FL)................  Escambia Operating     58.8 ppb (FL) (based   Yes, into FL (the
                                                                                      Company-Flomaton       on 2013-2015 actual    northern portion of
                                                                                      (AL) and Breitburn     emissions for the      Escambia County,
                                                                                      Operating, L.P. (FL).  thermal oxidizer at    FL).
                                                                                                             Big Escambia and
                                                                                                             allowable/PTE
                                                                                                             emissions for the
                                                                                                             remaining units at
                                                                                                             Big Escambia and the
                                                                                                             nearby sources).
Continental Carbon.................  Russell...............  1 (GA)................  IIG MinWool LLC (AL).  38.9 (GA) (based on    Yes, into GA (the
                                                                                                             PTE emissions).        southwestern portion
                                                                                                                                    of Muscogee County
                                                                                                                                    and the northwestern
                                                                                                                                    portion of
                                                                                                                                    Chattahoochee
                                                                                                                                    County).
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Table 3 provides a summary of the modeling results for the four DRR 
sources in neighboring states which are located within 50 km of Alabama 
and which elected to provide air dispersion modeling under the DRR: 
Gulf Power Company--Crist Electric Generating Station (Crist) in 
Florida; Georgia Power--Plant Bowen (Plant Bowen) and Georgia Power--
Plant Wansley (Plant Wansley) in Georgia; and Mississippi Power 
Company's Victor J. Daniel Steam Electric Generating Plant (Plant 
Daniel) in Mississippi. The modeling results for all four sources 
indicated that the maximum impacts did not exceed the level of the 2010 
1-hour SO2 NAAQS.\30\
---------------------------------------------------------------------------

    \29\ As used in the heading for this table, the term ``valid'' 
means valid for the purpose of evaluating impacts for interstate 
transport of the 2010 1-hour SO2 NAAQS from Alabama in 
neighboring states.
    \30\ Although the modeling grids for Crist, Plant Bowen, and 
Plant Wansley do not extend into Alabama, EPA finds that the model 
results for these sources which show that the maximum impacts did 
not exceed the level of the 2010 1-hour SO2 NAAQS 
indicate that there is not a transport issue in the areas modeled 
for which there is data.

                                    Table 3--Other States' Sources With DRR Modeling Located Within 50 km of Alabama
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                Modeled 99th
                                                                     Approximate                              percentile daily
                                                                    distance from       Other facilities       maximum 1-hour    Model grid extends into
              DRR source                     County (state)           source to       included in modeling           SO2             another state?
                                                                   Alabama border                               concentration
                                                                        (km)                                       (ppb) *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Crist.................................  Escambia (FL)...........                17  Yes--International Paper              33.8  No.
                                                                                     Pensacola Facility.
Plant Bowen...........................  Bartow (GA).............                46  No......................              57.6  No.
Plant Wansley.........................  Heard (GA)..............                24  Yes--Georgia Power--                    15  No.
                                                                                     Plant Yates; Municipal
                                                                                     Electric Authority of
                                                                                     Georgia; Chattahoochee
                                                                                     Energy Facility; and
                                                                                     Wansley Combined-Cycle
                                                                                     Generating Plant.
Plant Daniel..........................  Jackson (MS)............                14  None....................              56.5  Yes--into AL (a portion
                                                                                                                                 of extreme southwest AL
                                                                                                                                 west of Mobile County,
                                                                                                                                 AL).
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The modeled 99th percentile daily maximum 1-hour SO2 concentrations are based on: 2012-2014 actual SO2 emissions for Crist and Plant Daniel; 2012-2014
  actual SO2 emissions for Plant Wansley; PTE for the other sources included in Plant Wansley's modeling; and 2014-2016 actual SO2 emissions for Plant
  Bowen.

    EPA believes that the modeling results in Tables 2 and 3, weighed 
along with other factors in this notice, support EPA's proposed 
conclusion that sources in Alabama will not contribute significantly to 
nonattainment of the 2010 1-hour SO2 NAAQS in any other 
state.
2. SO2 Emissions Analysis
a. State Submission
    With respect to emissions trends, ADEM states that significant 
SO2 emissions reductions have resulted from the 
implementation of several federal programs in Alabama. These federal 
programs are identified in section III.C.5 of this notice.
b. EPA Analysis
    EPA reviewed statewide and EGU SO2 emissions in Alabama 
from the NEI for the years 2005, 2008, 2011, and 2014 to examine any 
trends in SO2 emissions over this period. As shown in Table 
4, Alabama's statewide SO2 emissions have declined by 66 
percent from 592,670 tons in 2002 to 201,418 tons in 2014. Alabama EGU 
SO2 emissions decreased by 74 percent from 461,634 tons in 
2005 to 119,976 tons in 2014.

[[Page 72284]]



                               Table 4--Alabama SO2 Emissions (tons) From the NEI
----------------------------------------------------------------------------------------------------------------
                                                                     2008 NEI        2011 NEI        2014 NEI
                                                     2005 NEI       (Version 3)     (Version 2)     (Version 2)
----------------------------------------------------------------------------------------------------------------
Total SO2 Emissions.............................         592,670         443,810         278,364         201,418
SO2 Emissions from EGUs.........................         461,634         362,671         179,849         119,976
----------------------------------------------------------------------------------------------------------------

    As discussed in section III.B., EPA also finds that it is 
appropriate to examine the impacts of SO2 emissions from 
stationary sources emitting greater than 100 tons of SO2 in 
Alabama at distances ranging from zero km to 50 km from a neighboring 
state's border. Therefore, in addition to those sources addressed in 
section III.C.1.b. of this notice, EPA also assessed the potential 
impacts of SO2 emissions from stationary sources not subject 
to the DRR that emitted over 100 tons of SO2 in 2017 and are 
located in Alabama within 50 km from the border.\31\ EPA assessed this 
information to evaluate whether the SO2 emissions from these 
sources could interact with SO2 emissions from the nearest 
source in a neighboring state in such a way as to impact a violation of 
the 2010 1-hour SO2 NAAQS in that state. Table 5 lists 
sources in Alabama not subject to the DRR that emitted greater than 100 
tpy of SO2 in 2017 within 50 km of the State's border.
---------------------------------------------------------------------------

    \31\ 2017 emissions are the latest available data for these 
sources in Alabama.
---------------------------------------------------------------------------

    Currently, EPA does not have monitoring or modeling data suggesting 
that Florida, Georgia, North Carolina, and Tennessee are impacted by 
SO2 emissions from the 14 Alabama sources not subject to the 
DRR listed in Table 5. Of these 14 Alabama sources, 10 are located over 
50 km from the nearest source in another state emitting over 100 tons 
of SO2. EPA believes that the distances greater than 50 km 
between sources make it unlikely that SO2 emissions from the 
10 Alabama sources could interact with SO2 emissions from 
the neighboring states' nearest sources in Table 5 in such a way as to 
contribute significantly to nonattainment in Florida, Georgia, 
Mississippi, and Tennessee.

                           Table 5--Alabama Non-DRR SO2 Sources Emitting Greater Than 100 tpy in 2017 Near Neighboring States
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                Approximate
                                                              Approximate                                       distance to    Nearest neighboring state
                                          2017 Annual SO2     distance to                                         nearest         non-DRR SO2 source &
             Alabama source              emissions (tons)   Alabama  border    Closest  neighboring  state      neighboring      2017  emissions (>100
                                                                 (km)                                        state SO2 source          tons SO2)
                                                                                                                    (km)
--------------------------------------------------------------------------------------------------------------------------------------------------------
American Midstream Chatom, LLC.........               948                 5  Mississippi...................                44  Petro Harvester Operating
                                                                                                                                Company LLC--South
                                                                                                                                Cypress Creek (Petro-
                                                                                                                                Cypress Creek) (128
                                                                                                                                tons).
Evonik Corporation.....................               225                25  Mississippi...................                41  Plant Daniel (204 tons).
ExxonMobil Production Company..........               157                19  Mississippi...................                37  Plant Daniel (204 tons).
Georgia-Pacific (Penington)............             1,236                37  Mississippi...................                70  Petro-Cypress Creek (128
                                                                                                                                tons).
Georgia-Pacific Brewton LLC............               103                 8  Florida.......................                16  Breitburn Operating LP
                                                                                                                                (1,491 tons).
Georgia-Pacific Cedar Springs LLC......               512                <5  Georgia.......................                96  Georgia Power Company--
                                                                                                                                Plant Mitchell (633 tons
                                                                                                                                in 2015).
Hilcorp Energy Company.................               126                33  Mississippi...................                60  Plant Daniel (204 tons).
MeadWestvaco Mahrt Mill................               222                <5  Georgia.......................                85  C-E Minerals Plants 1, 2,
                                                                                                                                and 6 (292 tons).
Mineral Manufacturing Corporation......               182                 5  Georgia.......................               109  C-E Minerals Plants 1, 2,
                                                                                                                                and 6 (292 tons).
Nucor Steel Decatur LLC................               110                39  Tennessee.....................               102  Steel Dynamics Columbus
                                                                                                                                (457 tons).
Rock-Tenn Mill Company, LLC............               250                38  Mississippi...................                90  Petro-Cypress Creek (128
                                                                                                                                tons).
SSAB Alabama Inc.......................               381                39  Mississippi...................                70  Plant Daniel (204 tons).
Tennessee Alloys Corporation...........               671                <5  Tennessee and Georgia.........                93  Resolute Forest Products--
                                                                          9                                                     Calhoun Operations (TN)--
                                                                                                                                (218 tons).
Union Oil of California--Chunchula Gas              * 105                29  Mississippi...................                60  Plant Daniel (204 tons).
 Plant.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* (2016 Emissions).

    There are four Alabama sources not subject to the DRR that are 
located at or less than 50 km from the nearest source in another state 
which emit greater than 100 tons of SO2: American Midstream 
Chatom, LLC; Evonik Corporation; ExxonMobil Production Company; and 
Georgia-Pacific Brewton LLC. EPA believes that the relatively low 
SO2 emissions of each of these four Alabama sources combined 
with the emissions from the nearest sources emitting greater than 100 
tons of SO2 in neighboring states make it unlikely that the 
SO2 emissions from these four Alabama

[[Page 72285]]

sources could interact with SO2 emissions from the 
neighboring states' sources in such a way as to contribute 
significantly to nonattainment in the neighboring states of Florida, 
Georgia, Mississippi, and Tennessee.
    In addition, EPA evaluated 2017 SO2 emissions data for 
four of the five DRR sources for which EPA could not rely on existing 
DRR modeling to assess their impacts for interstate transport for the 
2010 1-hour SO2 NAAQS on other states: AkzoNobel, Ascend, 
Lowman, and Plant Barry. Table 6 provides annual 2017 SO2 
emissions data along with the distances to the closest neighboring 
state's sources emitting over 100 tpy of SO2.\32\ Table 7 
shows the SO2 emissions trends for these sources from 2012-
2017 (and 2018 if data is available).\33\
---------------------------------------------------------------------------

    \32\ Table 6 SO2 emissions are from EPA's Air Markets 
Program Data (AMPD) accessible at: https://ampd.epa.gov/ampd/. EPA's 
AMPD is an application that provides both current and historical 
data collected as part of EPA's emissions trading programs.
    \33\ Table 7 SO2 emissions for Lowman and Plant Barry 
are from EPA's AMPD.

                                   Table 6--Alabama DRR SO2 Sources Without Valid DRR Modeling Near Neighboring States
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                               Approximate
                                             2017 Annual                                                       distance to    Nearest neighboring state
                                            SO2 emissions    Approximate                                         nearest     SO2 source & 2017 Emissions
              Alabama source                   (tons)        distance to      Closest  neighboring  state      neighboring         (>100 Tons SO2)
                                                            Alabama (km)                                        state SO2
                                                                                                               source (km)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ascend...................................           1,628              40  Tennessee.......................             123  Packaging Corp. of America
                                                                                                                              (616 tons).
Lowman...................................           1,110              51  Mississippi.....................              73  Petro-Cypress Creek (128
                                                                                                                              tons).
Plant Barry..............................           4,218              40  Mississippi.....................              74  Plant Daniel (204 tons).
AkzoNobel................................           2,201              39  Mississippi.....................              71  Plant Daniel (204 tons).
--------------------------------------------------------------------------------------------------------------------------------------------------------


                        Table 7--Alabama DRR SO2 Sources Emitting Greater Than 100 tpy Near Neighboring States--Emissions Trends
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Alabama source                    2012            2013            2014            2015            2016            2017            2018
--------------------------------------------------------------------------------------------------------------------------------------------------------
AkzoNobel...............................           3,293           2,752           2,320           3,587           3,646           2,201           N/A *
Ascend..................................           2,182           2,595           2,839           2,594           2,179           1,628           N/A *
Lowman..................................           3,619           3,893           4,546           2,506           1,241           1,110             808
Plant Barry.............................          10,731          13,448          10,690           8,688           5,421           4,218           5,257
--------------------------------------------------------------------------------------------------------------------------------------------------------
* 2018 emissions not yet available for AkzoNobel and Ascend from EPA's Emissions Inventory System (EIS).

    Table 6 shows that the distances between the four Alabama DRR 
sources without valid DRR modeling and the nearest state's source 
emitting over 100 tpy of SO2 exceed 50 km. EPA believes that 
the distances greater than 50 km between sources make it unlikely that 
SO2 emissions from the four Alabama DRR sources could 
interact with SO2 emissions from the neighboring states' 
nearest sources in Table 6 in such a way as to contribute significantly 
to nonattainment in Mississippi and Tennessee. Table 7 shows that 2017 
SO2 emissions have declined below 2012 levels for Ascend and 
Akzo Nobel) and that 2018 SO2 emissions have declined below 
2012 levels for Lowman and Plant Barry.
    EPA also considered whether any changes in controls or operations 
had occurred at AkzoNobel, Ascend, Lowman, and Plant Barry. AkzoNobel 
entered into a consent decree with EPA that has reduced SO2 
emissions.\34\ According to June 6, 2019, and December 2, 2019, emails 
from ADEM to EPA, Ascend ceased operating Boiler 5, Boiler 6 is set to 
cease operations in 2020, and Cokers 1 and 2 are set to cease 
operations in 2021.\35\ At Loman, three coal-fired boilers are set to 
be shut down in 2020. Plant Barry has retired Unit 3, and Units 1 and 2 
are restricted to burn only natural gas as of January 1, 2017.
---------------------------------------------------------------------------

    \34\ The consent decree, entered on November 21, 2019, is 
available at: https://www.justice.gov/enrd/consent-decree/file/1201231/download. A press release is available at: https://www.epa.gov/newsreleases/settlement-reached-nouryon-functional-chemicals-llc-fka-akzo-nobel-functional-chemicals.
    \35\ ADEM's June 6, 2019, and December 2, 2019, emails are 
included in the docket for this action at www.regulations.gov at 
Docket ID No. EPA-R04-OAR-2018-0792.
---------------------------------------------------------------------------

    EPA also evaluated data in EPA's Air Quality System (AQS) \36\ from 
the SO2 monitors in the surrounding areas of AkzoNobel, 
Ascend, Lowman, and Plant Barry. The only monitor within 50 km of these 
sources is located in Mobile County, Alabama (AQS ID: 01-097-0003) and 
is approximately 23 km from AkzoNobel. The 2018 DV for this monitor is 
11 ppb.
---------------------------------------------------------------------------

    \36\ EPA's AQS contains ambient air pollution data collected by 
EPA, state, local, and tribal air pollution control agencies. This 
data is available at https://www.epa.gov/air-trends/air-quality-design-values.
---------------------------------------------------------------------------

    Based on the declining SO2 emissions trends in Alabama 
shown in Table 4, and the Agency's analysis of the Alabama sources and 
respective data in Tables 5, 6, and 7, EPA believes that Alabama's 
potential for contributing significantly to nonattainment in a nearby 
state is reduced substantially.
3. SO2 Ambient Air Quality
a. State Submission
    In its August 20, 2018, SIP submission, ADEM indicated that there 
is one SO2 monitor located in the State with complete 
data.\37\ This monitor (AQS ID: 01-073-1003) is located in Jefferson 
County, Alabama, and has a 2015-2017 DV of 13 ppb. The monitor is well 
over 50 km from the State's border. ADEM also asserts that there are no 
monitors located in Florida, Georgia, Louisiana, Mississippi, or 
Tennessee that are violating the 2010 1-hour SO2 NAAQS for 
the 2015-2017 monitoring period based on the DVs in EPA's AQS for these 
monitors.
---------------------------------------------------------------------------

    \37\ At the time of SIP submission, the Jefferson County, 
Alabama, monitor (AQS ID: 01-073-1003) was the only monitor with a 
valid DV for the 2015-2017 time period.
---------------------------------------------------------------------------

b. EPA Analysis
    EPA reviewed monitoring data for AQS monitors in Alabama within 50 
km

[[Page 72286]]

of another state and for AQS monitors within 50 km of Alabama in 
adjacent states using relevant data from EPA's AQS DV reports. The 2010 
1-hour SO2 standard is violated at an ambient air quality 
monitoring site (or in the case of dispersion modeling, at an ambient 
air quality receptor location) when the 3-year average of the annual 
99th percentile of the daily maximum 1-hour average concentrations 
exceeds 75 ppb, as determined in accordance with Appendix T of 40 CFR 
part 50. The only AQS monitors in Alabama within 50 km of another state 
are the Mobile County monitor (AQS ID: 01-097-0003), and the Sumter 
County monitor (AQS ID: 01-119-0003). The Mobile County monitor is 
approximately 30 km from Mississippi and 45 km from Florida, and the 
Sumter County monitor is approximately 13 km from Mississippi. The 
Mobile County monitor began operation on January 1, 2016. The monitor 
has a complete, quality-assured 2016-2018 DV of 11 ppb, which is 85 
percent below the level of the 2010 1-hour SO2 NAAQS. The 
Sumter County monitor began operation on January 1, 2018. Since the 
monitor has not operated for three years, it has not yet collected a 
valid DV. During 2018, the Sumter County monitor recorded a 99th 
percentile daily maximum 1-hour SO2 concentration of 
approximately 4 ppb. Neither the Mobile County nor Sumter County 
monitor has measured any daily exceedances of the 2010 1-hour 
SO2 NAAQS during their respective years of operation.
    Table 8 shows that there are three AQS monitors in the adjacent 
states of Florida (Escambia County monitor), Georgia (Floyd County 
monitor), and Mississippi (Jackson County monitor) which are located 
within 50 km of the Alabama border. Currently, there are no AQS 
monitors with complete, valid data indicating a violation of the 2010 
1-hour SO2 NAAQS located within 50 km of Alabama in the 
states of Florida, Georgia, and Mississippi. Further, the DVs from 
these monitors show a general downward trend in SO2 
concentrations and that the DVs from 2012-2018 have remained below the 
standard, with the exception of the Floyd County monitor in Georgia 
which did not have a valid DV for 2015-2017 and 2016-2018.\38\
---------------------------------------------------------------------------

    \38\ The Floyd County, Georgia monitor (AQS ID: 13-115-0003) was 
relocated in January 2017 to the opposite side of the International 
Paper-Rome facility to characterize the area of expected maximum 1-
hour SO2 concentration near the source under the DRR. The 
relocated monitor (AQS ID: 13-115-0006) is shown in Table 9 of this 
notice and does not have a valid 2016-2018 DV due to the relocation.

                                             Table 8--2010 1-Hour SO2 DVs (ppb) for AQS Monitors Located in Adjacent States Within 50 km of Alabama
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                                                                     Approximate
                                                                                                                                                                                     distance to
                   State                                 County                AQS ID      2010-2012    2011-2013    2012-2014    2013-2015    2014-2016    2015-2017    2016-2018      state
                                                                                                                                                                                     border (km)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Florida....................................  Escambia.....................   12-033-0004           27           22           25           24           16            8            6           23
Georgia....................................  Floyd........................   13-115-0003           74           67           46           35           42         * ND         * ND           12
Mississippi................................  Jackson......................   28-059-0006           27           23           27           28           21           12            6           13
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* ND indicates no data due to relocation of the Floyd County, Georgia monitor to serve as a DRR monitor (AQS ID: 13-115-0006) listed in Table 8.

    EPA notes that the 2014-2016 DV for the Floyd County, Georgia AQS 
monitor (AQS ID: 13-115-0003) of 42 ppb is 44 percent below the level 
of the 2010 1-hour SO2 NAAQS. None of the monitors listed in 
Table 8 has measured any daily exceedances of the 2010 1-hour 
SO2 NAAQS during 2017 or 2018. Thus, based on this 
assessment, EPA believes that these data support EPA's proposed 
conclusion that Alabama will not contribute significantly to 
nonattainment of the 2010 1-hour SO2 NAAQS in any other 
state.
    EPA also evaluated monitoring data provided to date for AQS 
monitors located in states adjacent to Alabama within 50 km of the 
State's border that were established to characterize the air quality 
around specific sources subject to EPA's DRR to inform the Agency's 
future round 4 designations for the 2010 1-hour SO2 NAAQS in 
lieu of modeling (hereinafter referred to as ``DRR monitors''). There 
is only one DRR monitor--located in Floyd County, Georgia (AQS ID: 13-
115-0006)--that is within 50 km of the Alabama border. Although this 
monitor does not have three or more years of complete data to establish 
DVs, EPA evaluated the available, annual 99th percentile SO2 
concentration data for 2017 and 2018 (see Table 9). The Floyd County 
DRR monitor was sited in the vicinity of the International Paper--Rome 
facility, a DRR source.

    Table 9--Annual 99th Percentile of 1-Hour Daily Maximum SO2 Concentrations (ppb) for Round 4 DRR Monitors
                               Located in Adjacent States Within 50 km of Alabama
----------------------------------------------------------------------------------------------------------------
                                                                     2017 99th       2018 99th      Approximate
        County (state)               Round 4          AQS ID        percentile      percentile      distance to
                                monitored source                   concentration   concentration   Alabama (km)
----------------------------------------------------------------------------------------------------------------
Floyd (GA)....................  International        13-115-0006              22              15              12
                                 Paper--Rome.
----------------------------------------------------------------------------------------------------------------

    Though the annual 99th percentile daily maximum 1-hour 
SO2 concentrations shown in Table 9 are not directly 
comparable to a DV for the 2010 1-hour SO2 NAAQS, which is 
in the form of the 3-year average of the 99th percentile of daily 
maximum 1-hour values, EPA notes that the highest annual 99th 
percentile daily maximum 1-hour values observed at the Floyd County DRR 
monitor in 2017 and 2018 were 22 ppb and 15 ppb, respectively. The 
Floyd County DRR monitor has not measured any daily exceedances of the 
2010 1-hour SO2 NAAQS during 2017 or 2018. After careful 
review of the State's assessment and all available monitoring data, EPA 
believes that the AQS monitoring data assessed support EPA's proposed 
conclusion that Alabama will not contribute significantly to 2010 1-
hour SO2 violations in the neighboring states.

[[Page 72287]]

4. SIP-Approved Regulations Addressing SO2 Emissions
a. State Submission
    Alabama's August 20, 2018, SIP submission identifies SIP-approved 
measures which help ensure that SO2 emissions in the State 
will not contribute significantly to nonattainment of the 2010 1-hour 
SO2 NAAQS in any other state. Specifically, ADEM lists the 
following SIP-approved Alabama regulations which establish emission 
limits and other control measures for SO2: ADEM 
Administrative Code Chapter 335-3-5--Control of Sulfur Compound 
Emissions and Rules 335-3-14-.01--General Provisions; 335-3-14-.02--
Permit Procedure; 335-3-14-.03--Standards for Granting Permits; 335-3-
14-.04--Air Permits Authorizing Construction in Clean Air Areas 
(Prevention of Significant Deterioration (PSD)); and 335-3-14-.05--Air 
Permits Authorizing Construction in or Near Nonattainment Areas.
b. EPA Analysis
    EPA believes that Alabama's SIP-approved measures summarized in 
III.C.4.a. of this notice, which establish emissions limits, permitting 
requirements, and other control measures for SO2, 
effectively address emissions of SO2 from sources in the 
State. For the purposes of ensuring that SO2 emissions at 
new major sources or major modifications at existing major sources in 
Alabama do not contribute significantly to nonattainment or interfere 
with maintenance of the 2010 1-hour SO2 NAAQS, the State has 
a SIP-approved major source new source review (NSR) program. Alabama's 
SIP-approved nonattainment NSR regulation, Rule 335-3-14-.05, applies 
to the construction of any new major stationary source or major 
modification at an existing major stationary source in an area 
designated as nonattainment. Alabama's SIP-approved prevention of 
significant deterioration (PSD) regulation, Rule 335-3-14-.04, applies 
to the construction of any new major stationary source or any major 
modification at an existing major stationary source in an area 
designated as attainment or unclassifiable or not yet designated. Rules 
335-3-14-.01--General Provisions, 335-3-14-.02--Permit Procedure, and 
335-3-14-.03--Standards for Granting Permits govern the preconstruction 
permitting of modifications to and construction of minor stationary 
sources. These major and minor NSR rules ensure that SO2 
emissions due to major modifications at existing major stationary 
sources, modifications at minor stationary sources, and the 
construction of new major and minor sources in Alabama will not 
contribute significantly to nonattainment of the 2010 1-hour 
SO2 NAAQS in neighboring states.
5. Federal Regulations Addressing SO2 Emissions in Alabama
a. State Submission
    ADEM identified EPA programs which, either directly or indirectly, 
have significantly reduced SO2 emissions in Alabama. These 
programs include: 2007 Heavy-Duty Highway Rule; Acid Rain Program; 
Cross-State Air Pollution Rule; National Emission Standards for 
Hazardous Air Pollutants; New Source Performance Standards; Nonroad 
Diesel Rule; and Tier 1 and 2 Mobile Source Rules.
b. EPA Analysis
    In addition to the list of federal regulations identified in 
section III.C.5.a. of this notice which contribute to SO2 
reductions in Alabama, EPA notes that some facilities in the State are 
also subject to the federal requirements contained in EPA's Mercury Air 
Toxic Standards (MATS). These regulations reduce acid gases, which also 
result in reductions of SO2 emissions. EPA believes that the 
federal control measures for SO2 which Alabama lists in the 
State's SIP submission, along with MATS, may lower SO2 
emissions, which, in turn, are expected to continue to support EPA's 
proposed conclusion that SO2 emissions from Alabama will not 
contribute significantly to nonattainment of the 2010 1-hour 
SO2 NAAQS in another state.
6. Conclusion
    EPA proposes to determine that Alabama's August 20, 2018, SIP 
submission satisfies the requirements of prong 1 of CAA section 
110(a)(2)(D)(i)(I). This proposed determination is based on the 
following considerations: Current air quality data for AQS 
SO2 monitors located in the states of Florida, Georgia, and 
Mississippi that are within 50 km of Alabama's border are well below 
the 2010 1-hour SO2 NAAQS; modeling for the two Alabama DRR 
sources whose modeling grids extend into a portion of other states 
indicate that the maximum impacts did not exceed the level of the 2010 
1-hour SO2 NAAQS in neighboring states; modeling for four 
DRR sources in the surrounding states of Florida, Georgia, and 
Mississippi located within 50 km of Alabama indicate that the areas 
around these sources do not violate the 2010 1-hour SO2 
NAAQS; declining statewide and EGU SO2 emissions from 2005 
to 2014 in Alabama suggest that the State's potential for contributing 
significantly to nonattainment of the 2010 1-hour SO2 NAAQS 
is reduced substantially; SO2 emissions from Alabama sources 
not subject to the DRR and which emitted over 100 tons of 
SO2 in 2017 are not likely interacting with SO2 
emissions from the nearest sources in bordering states in such a way as 
to contribute significantly to nonattainment in the surrounding states 
of Florida, Georgia, Mississippi, and Tennessee; Alabama DRR sources 
without valid DRR modeling are located over 50 km from the nearest 
state's SO2 source and their SO2 emissions show 
an overall general downward trend; and the implementation of current 
Alabama SIP-approved measures and federal emissions control programs 
help to further reduce and control SO2 emissions from 
sources within Alabama. Further, EPA has no information indicating that 
Alabama sources will contribute significantly to nonattainment of the 
2010 1-hour SO2 NAAQS in another state.
    Based on the analysis provided by Alabama in its SIP submission and 
EPA's analysis of the factors described in section III.C, EPA proposes 
to find that sources within Alabama will not contribute significantly 
to nonattainment of the 2010 1-hour SO2 NAAQS in any other 
state.

D. EPA's Prong 2 Evaluation--Interference With Maintenance of the NAAQS

    Prong 2 of the good neighbor provision requires state plans to 
prohibit emissions that will interfere with maintenance of a NAAQS in 
another state.
1. State Submission
    In its August 20, 2018, SIP submission, ADEM relied upon the 
information provided for prong 1 to demonstrate that emissions within 
Alabama will not interfere with maintenance of the 2010 1-hour 
SO2 NAAQS in any neighboring state. Further, ADEM notes that 
there are no monitors located in the surrounding states of Florida, 
Georgia, Louisiana, Mississippi, and Tennessee that are violating the 
2010 1-hour SO2 NAAQS for the 2015-2017 monitoring period. 
ADEM also highlighted the State's PSD regulation (335-3-14-.04) and 
states that this regulation ``will continue to apply to any future, 
large sources in Alabama, further ensuring that maintenance efforts in 
neighboring states are addressed.''

[[Page 72288]]

2. EPA Analysis
    In North Carolina v. EPA, the United States Court of Appeals for 
the District of Columbia Circuit (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. North Carolina v. EPA, 531 F.3d 896, 910-11 (D.C. 
Cir. 2008). EPA interprets prong 2 to require an evaluation of the 
potential impact of a state's emissions on areas that are currently 
measuring clean data, but that may have issues maintaining that air 
quality. Therefore, in addition to the analysis presented by Alabama, 
EPA has also reviewed additional information on SO2 air 
quality and emission trends to evaluate the State's conclusion that 
Alabama will not interfere with maintenance of the 2010 1-hour 
SO2 NAAQS in downwind states. This evaluation builds on the 
analysis regarding significant contribution to nonattainment (prong 1).
    For the prong 2 analysis, EPA evaluated the data discussed in 
section III.C. of this notice for prong 1, with a specific focus on 
evaluating emissions trends in Alabama, analyzing air quality data, and 
assessing how future sources of SO2 are addressed through 
existing SIP-approved and federal regulations. Given the continuing 
trend of decreasing statewide SO2 emissions from sources 
within Alabama, and the fact that all areas in other states within 50 
km of the Alabama border have DVs attaining the 2010 1-hour 
SO2 NAAQS, EPA believes that evaluating whether these 
decreases in emissions can be maintained over time is a reasonable 
criterion to ensure that sources within Alabama do not interfere with 
its neighboring states' ability to maintain the 2010 1-hour 
SO2 NAAQS.
    With respect to air quality data trends, the valid 2016-2018 DVs 
for AQS SO2 monitors both in Alabama within 50 km of another 
state's border and in adjacent states within 50 km of Alabama's border 
are below the 2010 1-hour SO2 NAAQS.\39\ Further, modeling 
results for DRR sources in the State within 50 km of Alabama's border 
did not exceed the level of the 2010 1-hour SO2 NAAQS in 
neighboring states and modeling results for DRR sources in neighboring 
states within 50 km of Alabama's border show maximum impacts did not 
exceed the level of the 2010 1-hour SO2 NAAQS. Thus, these 
modeling results demonstrate that Alabama's largest point sources of 
SO2 are not expected to interfere with maintenance of the 
2010 1-hour SO2 NAAQS in another state.
---------------------------------------------------------------------------

    \39\ As noted in Section III.C.3.b, the Floyd County, Georgia 
monitor (AQS ID: 13-115-0003) does not have a valid 2016-2018 DV as 
this monitor was relocated in January 2017 to the opposite side of 
the International Paper-Rome facility to characterize the area of 
expected maximum 1-hour SO2 concentration near the source 
under the DRR.
---------------------------------------------------------------------------

    As discussed in sections III.C.4 and III.C.5, EPA believes that 
federal and SIP-approved State regulations that both directly and 
indirectly reduce emissions of SO2 in Alabama help ensure 
that the State does not interfere with maintenance of the NAAQS in 
another state. SO2 emissions from future major modifications 
and new major sources will be addressed by Alabama's SIP-approved major 
NSR regulations described in section III.C.4. In addition, ADEM Rules 
335-3-14-.01--General Provisions, 335-3-14-.02--Permit Procedure, and 
335-3-14-.03--Standards for Granting Permits govern the preconstruction 
permitting of modifications to and construction of minor stationary 
sources. These major and minor source permitting regulations are 
designed to ensure that emissions from these activities will not 
interfere with maintenance of the 2010 1-hour SO2 NAAQS in 
the State or in any other state.
3. Conclusion
    EPA proposes to determine that Alabama's August 20, 2018, SIP 
submission satisfies the requirements of prong 2 of CAA section 
110(a)(2)(D)(i)(I). This determination is based on the following 
considerations: Statewide and EGU SO2 emissions from 2005 to 
2014 in Alabama have declined significantly (66 and 74 percent, 
respectively); current Alabama SIP-approved measures and federal 
emissions control programs adequately control SO2 emissions 
from sources within Alabama; Alabama's SIP-approved PSD and minor 
source NSR permit programs will address future large and small 
SO2 sources; current air quality data for AQS SO2 
monitors in Florida, Georgia, and Mississippi within 50 km of Alabama's 
border have DVs well below the 2010 1-hour SO2 NAAQS; and 
modeling for DRR sources in Alabama indicate that the maximum impacts 
did not exceed the level of the 2010 1-hour SO2 NAAQS in 
neighboring states; modeling for DRR sources within 50 km of Alabama's 
border located in the states of Florida, Georgia, and Mississippi 
demonstrate that Alabama's largest point sources of SO2 will 
not interfere with maintenance of the 2010 1-hour SO2 NAAQS 
in another state. Based on the analysis provided by Alabama in its SIP 
submission and EPA's analysis of the factors described in section III.C 
of this notice, EPA proposes to find that emission sources within 
Alabama will not interfere with maintenance of the 2010 1-hour 
SO2 NAAQS in any other state.

IV. Proposed Action

    In light of the above analysis, EPA is proposing to approve 
Alabama's August 20, 2018, SIP submission as demonstrating that 
emissions from Alabama will not contribute significantly to 
nonattainment or interfere with maintenance of the 2010 1-hour 
SO2 NAAQS in another state.

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. See 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, EPA's role is to approve state choices, 
provided that they meet the criteria of the CAA. This proposed action 
merely proposes to approve state law as meeting federal requirements 
and does not impose additional requirements beyond those imposed by 
state law. For that reason, this proposed action:
     Is not a significant regulatory action subject to review 
by the Office of Management and Budget under Executive Orders 12866 (58 
FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 2011);
     Is not an Executive Order 13771 (82 FR 9339, February 2, 
2017) regulatory action because SIP approvals are exempted under 
Executive Order 12866;
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the 
National

[[Page 72289]]

Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) 
because application of those requirements would be inconsistent with 
the CAA; and
     Does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    The SIP is not approved to apply on any Indian reservation land or 
in any other area where 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 as specified by Executive Order 
13175 (65 FR 67249, November 9, 2000), nor will it impose substantial 
direct costs on tribal governments or preempt tribal law.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Particulate matter, Reporting 
and recordkeeping requirements, Sulfur oxides.

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

    Dated: December 17, 2019.
Blake M. Ashbee,
Acting Regional Administrator, Region 4.
[FR Doc. 2019-28236 Filed 12-30-19; 8:45 am]
BILLING CODE 6560-50-P


