Interstate Transport Prongs 1 and 2 for the 2010 Sulfur Dioxide (SO2, 31645-31659 [2021-12501]
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Proposed Rules
Federal Register
Vol. 86, No. 113
Tuesday, June 15, 2021
This section of the FEDERAL REGISTER
contains notices to the public of the proposed
issuance of rules and regulations. The
purpose of these notices is to give interested
persons an opportunity to participate in the
rule making prior to the adoption of the final
rules.
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Part 52
[EPA–R07–OAR–2021–0365; FRL–10024–
81–Region 7]
Interstate Transport Prongs 1 and 2 for
the 2010 Sulfur Dioxide (SO2) Standard
for Kansas and Nebraska
Environmental Protection
Agency (EPA).
ACTION: Proposed rule.
AGENCY:
The Environmental Protection
Agency (EPA) is proposing to approve
State Implementation Plan (SIP)
submissions from Kansas and Nebraska
addressing the Clean Air Act (CAA or
Act) interstate transport SIP
requirements for the 2010 Sulfur
Dioxide (SO2) National Ambient Air
Quality Standards (NAAQS). These
submissions address the requirement
that each SIP contain adequate
provisions prohibiting air emissions that
will have certain adverse air quality
effects in other states. The EPA is
proposing to approve portions of these
infrastructure SIPs for the
aforementioned states as containing
adequate provisions to ensure that air
emissions in the states will not
significantly contribute to
nonattainment or interfere with
maintenance of the 2010 SO2 NAAQS in
any other state.
DATES: Comments must be received on
or before July 15, 2021.
ADDRESSES: The EPA has established a
docket for this action under Docket ID
No. EPA–R07–OAR–2021–0365. All
documents in the docket are listed on
the https://www.regulations.gov
website. Although listed in the index,
some information may not be publicly
available, i.e., Confidential Business
Information or other information whose
disclosure is restricted by statute.
Certain other material, such as
copyrighted material, is not placed on
the internet and will be publicly
available only in hard copy form.
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SUMMARY:
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Publicly available docket materials are
available either electronically through
www.regulations.gov or in hard copy at
the Atmospheric Programs Section, Air
Quality Planning Branch, Air and
Radiation Division, U.S. Environmental
Protection Agency, Region 7, 11201
Renner Boulevard, Lenexa, Kansas
66219. The EPA requests that if at all
possible, you contact the person listed
in the FOR FURTHER INFORMATION
CONTACT section to schedule your
inspection. The Regional Office’s
official hours of business are Monday
through Friday 8:30 a.m. to 4:30 p.m.,
excluding federal holidays.
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
keas.ashley@epa.gov.
SUPPLEMENTARY INFORMATION:
Throughout this document ‘‘we,’’ ‘‘us,’’
and ‘‘our’’ refer to the EPA.
Table of Contents
I. Written Comments
II. Background
A. Infrastructure SIPs
B. 2010 1-Hour SO2 NAAQS Designations
III. Relevant Factors To Evaluate 2010 SO2
Interstate Transport SIPs
IV. States’ Submissions and the EPA’s
Analysis
A. Kansas
1. State’s Analysis
2. The EPA’s Prong 1 Evaluation
3. The EPA’s Prong 2 Evaluation
B. Nebraska
1. State’s Analysis
2. The EPA’s Prong 1 Evaluation
3. The EPA’s Prong 2 Evaluation
V. Requirements for Approval of a SIP
Revision
VI. Proposed Action
VII. Statutory and Executive Order Reviews
I. Written Comments
Submit your comments, identified by
Docket ID No. EPA–R07–OAR–2021–
0365 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.
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The written comment is considered the
official comment and should include
discussion of all points you wish to
make. The EPA will generally not
consider comments or comment
contents located outside of the primary
submission (i.e. on the web, cloud, or
other file sharing system). For
additional submission methods, 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. Background
A. Infrastructure SIPs
On June 2, 2010, the EPA established
a new primary 1-hour SO2 NAAQS of 75
parts per billion (ppb), based on a threeyear average of the annual 99th
percentile of 1-hour daily maximum
concentrations.1 The CAA requires
states to submit, within three years after
promulgation of a new or revised
NAAQS, SIPs meeting the applicable
‘‘infrastructure’’ elements of sections
110(a)(1) and (2). One of these
applicable infrastructure elements, CAA
section 110(a)(2)(D)(i), requires SIPs to
contain ‘‘good neighbor’’ provisions to
prohibit certain adverse air quality
effects on neighboring states due to
interstate transport of pollution.
Section 110(a)(2)(D)(i) includes four
distinct components, commonly
referred to as ‘‘prongs,’’ that must be
addressed in infrastructure SIP
submissions. The first two prongs,
which are codified in section
110(a)(2)(D)(i)(I), require SIPs to contain
adequate provisions that prohibit any
source or other type of emissions
activity in one state from contributing
significantly to nonattainment of the
NAAQS in another state (prong 1) and
from interfering with maintenance of
the NAAQS in another state (prong 2).
The third and fourth prongs, which are
codified in section 110(a)(2)(D)(i)(II),
require SIPs to contain adequate
provisions that prohibit emissions
activity in one state from interfering
with measures required to prevent
significant deterioration of air quality in
another state (prong 3) or from
interfering with measures to protect
visibility in another state (prong 4).
1 75
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FR 35520 (June 22, 2010).
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In this action, the EPA is proposing to
approve the prong 1 and prong 2
portions of infrastructure SIP
submissions submitted by Kansas on
April 7, 2020, and Nebraska on October
27, 2020, as demonstrating that the SIP
contains adequate provisions to ensure
that air emissions from sources in these
states will not significantly contribute to
nonattainment or interfere with
maintenance of the 2010 SO2 NAAQS in
any other state or each other. All other
applicable infrastructure SIP
requirements for these SIP submissions
are addressed in separate rulemakings.
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B. 2010 1-Hour SO2 NAAQS
Designations
In this action, the EPA has considered
information from the 2010 1-hour SO2
NAAQS designations process, as
discussed in more detail in Section IV
of this document. For this reason, a brief
summary of the EPA’s designations
process for the 2010 1-hour SO2 NAAQS
is included here.2 All technical support
documents referenced throughout this
document are also included in the
docket for this action.
After the EPA establishes a new or
revised NAAQS, the 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
the 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, the EPA has the
authority to extend the deadline for
completing designations by up to one
year.
The EPA Administrator signed the
first round of designations (‘‘round 1’’) 3
2 While designations may provide useful
information for purposes of analyzing transport, the
EPA notes that designations themselves are not
dispositive of whether or not upwind emissions are
impacting areas in downwind states. The EPA has
consistently taken the position that CAA section
110(a)(2)(D) requires elimination of significant
contribution and interference with maintenance in
other states, and this analysis is not limited to
designated nonattainment areas. Nor must
designations for nonattainment areas have first
occurred before states or the EPA can act under
section 110(a)(2)(D). See e.g., Clean Air Interstate
Rule, 70 FR 25162, 25265 (May 12, 2005); CrossState Air Pollution Rule, 76 FR 48208, 48211 (Aug.
8, 2011); Final Response to Petition from New
Jersey Regarding SO2 Emissions From the Portland
Generating Station, 76 FR 69052 (Nov. 7, 2011)
(finding facility in violation of the prohibitions of
CAA section 110(a)(2)(D)(i)(I) with respect to the
2010 1-hour SO2 NAAQS prior to issuance of
designations for that standard).
3 The term ‘‘round’’ in this instance refers to
which ‘‘round of designations.’’
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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). The EPA
Administrator signed Federal Register
documents for round 2 designations 4 on
June 30, 2016 (81 FR 45039 (July 12,
2016)), and on November 29, 2016 (81
FR 89870 (December 13, 2016)), round
3 designations 5 on December 21, 2017
(83 FR 1098 (January 9, 2018)), and
round 4 designations 6 on December 21,
2020 (86 FR 16055 (March 26, 2021))
and on April 8, 2021 (86 FR 19576
(April 14, 2021)).7
At the time of this proposed action,
there are no nonattainment areas for the
2010 1-hour SO2 NAAQS in Kansas or
Nebraska. There are two areas
designated as unclassifiable, one in
Kansas and one in Nebraska, the
remaining areas in these states are
designated as attainment/unclassifiable.
III. Relevant Factors To Evaluate 2010
SO2 Interstate Transport SIPs
Although SO2 is emitted from a
similar universe of point and nonpoint
sources, interstate transport of SO2 is
unlike the transport of fine particulate
matter (PM2.5) or ozone, in that SO2 is
not a regional pollutant and does not
commonly contribute to widespread
nonattainment over a large (and often
multi-state) area. The transport of SO2 is
more analogous to the transport of lead
(Pb) because its physical properties
result in localized pollutant impacts
very near the emissions source.
However, ambient concentrations of SO2
do not decrease as quickly with distance
from the source as Pb because of the
physical properties and typical release
heights of SO2. Emissions of SO2 travel
farther and have wider ranging impacts
4 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 the EPA’s website for
SO2 designations at https://www.epa.gov/sulfurdioxide-designations.
5 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 the EPA’s website for
SO2 designations at https://www.epa.gov/sulfurdioxide-designations.
6 EPA and state documents and public comments
related to round 4 final designations are in the
docket at regulations.gov with Docket ID No. EPA–
HQ–OAR–2020–0037 and at the EPA’s website for
SO2 designations at https://www.epa.gov/sulfurdioxide-designations.
7 The Round 4 2010 SO NAAQS designations
2
action was signed by then EPA Administrator,
Andrew Wheeler, on December 21, 2020, pursuant
to a court-ordered deadline of December 31, 2020.
For administrative purposes only, and in
compliance with requirements of the Office of the
Federal Register, Acting Administrator Jane Nishida
re-signed the same action on March 10, 2021 for
publication in the Federal Register.
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than emissions of Pb but do not travel
far enough to be treated in a manner
similar to ozone or PM2.5. The
approaches that the EPA has adopted for
ozone or PM2.5 transport are too
regionally focused and the approach for
Pb transport is too tightly circumscribed
to the source. SO2 transport is therefore
a unique case and requires a different
approach.
Given the physical properties of SO2,
the EPA selected the ‘‘urban scale’’—a
spatial scale with dimensions from 4 to
50 kilometers (km) from point sources—
given the usefulness of that range in
assessing trends in both area-wide air
quality and the effectiveness of largescale pollution control strategies at such
point sources.8 The EPA’s selection of
this transport distance for SO2 is based
upon 40 CFR part 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
the 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. As such, the EPA utilized an
assessment up to 50 km from point
sources in order to assess trends in areawide air quality that might impact
downwind states.
As discussed in Section IV of this
proposed action, the EPA first reviewed
each state’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. The EPA then
conducted a weight of evidence
analysis, including review of each
state’s submission and other available
information, including air quality,
emission sources and emission trends
within the state and in bordering states
to which it could potentially contribute
or interfere.9
8 For the definition of spatial scales for SO ,
2
please see 40 CFR part 58, appendix D, section 4.4
(‘‘Sulfur Dioxide (SO2) Design Criteria’’). For further
discussion on how the EPA is applying these
definitions with respect to interstate transport of
SO2, see the EPA’s proposal on Connecticut’s SO2
transport SIP. 82 FR 21351, 21352, 21354 (May 8,
2017).
9 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 any of the subject state’s
air quality status. Any such future actions, such as
area designations under any NAAQS, will be based
on their own administrative records and the EPA’s
analyses of information that becomes available at
those times. Future available information may
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IV. States’ Submissions and EPA’s
Analysis
state. Table 1 shows emission trends for
the states addressed in this document
along with their neighboring states.10
Table 2 shows ambient air monitoring
data for monitors located within 50 km
of the borders of either Kansas or
Nebraska. Table 3 shows emissions
In this section, we provide an
overview of each state’s 2010 SO2
transport analysis, as well as the EPA’s
evaluation of prongs 1 and 2 for each
trends for sources in Kansas and
Nebraska emitting over 100 tons per
year (tpy) located within 50 km of the
border with another state. Tables 1, 2
and 3 will be referenced as part of the
EPA’s analysis for each state.
TABLE 1—STATEWIDE SO2 EMISSION TRENDS
[In tons per year]
State
2000
Colorado ...................................................
Iowa ..........................................................
Kansas .....................................................
Missouri ....................................................
Nebraska ..................................................
Oklahoma .................................................
South Dakota ...........................................
Wyoming ..................................................
2005
115,122
265,005
148,416
401,287
86,894
145,862
41,120
141,439
2010
80,468
222,419
199,006
425,167
121,785
169,464
28,579
122,453
60,459
142,738
80,267
321,059
77,898
136,348
16,202
91,022
2015
SO2
reduction,
2000–2019
(%)
2019
28,860
84,932
36,828
158,998
63,237
99,095
11,975
53,335
17,045
64,294
24,855
110,888
51,886
45,996
5,093
42,191
85
76
83
72
40
68
88
70
TABLE 2—SO2 MONITOR VALUES WITHIN 50 km OF THE NEBRASKA OR KANSAS BORDER
Site ID
Distance to
Kansas border
(km) *
(nearest state listed
for monitors in
Kansas)
Distance to
Nebraska border
(km) *
(nearest state listed
for monitors in
Nebraska)
461270001
202090021
310550053
310550019
310550057
290950034
400710604
400470555
305 .........................
2 (Missouri) ............
147 .........................
138 .........................
146 .........................
3 .............................
33 ...........................
54 ...........................
10 ...........................
114 .........................
0.5 (Iowa) ...............
4.5 (Iowa) ...............
1.5 (Iowa) ...............
118 .........................
367 .........................
387 .........................
State/area
South Dakota/Sioux City .................................................................
Kansas/Wyandotte County ..............................................................
Nebraska/Omaha ............................................................................
Nebraska/Omaha ............................................................................
Nebraska/Omaha ............................................................................
Missouri/Jackson County ................................................................
Oklahoma/Ponca City .....................................................................
Oklahoma/Enid ................................................................................
2017–2019
design value
(ppb) 11
3
6
41
24
34
10
28
48
* All distances throughout this document are approximations.
TABLE 3—SO2 EMISSION TRENDS FOR KANSAS AND NEBRASKA SOURCES WITHIN 50 km OF A STATE BORDER
State/county
Kansas/Johnson ........
Kansas/Linn ...............
Kansas/Douglas ........
Kansas/Wyandotte ....
Nebraska/Otoe ..........
Nebraska/Douglas .....
Nebraska/Cass ..........
Nebraska/Dodge ........
Nebraska/Kimball ......
Nebraska/Scotts Bluff
Nebraska/Douglas .....
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EIS facility
ID
Facility name
AGC Flat Glass ........................
Evergy—La Cygne ...................
Evergy—Lawrence ...................
Kansas City BPU—Nearman ...
Nebraska City Station ..............
North Omaha Station ...............
Ash Grove Cement Company ..
Lon D Wright Power Plant .......
Clean Harbors Environmental
Services.
Western Sugar Cooperative .....
Douglas County Recycling
Landfill.
include, and is not limited to, monitoring data and
modeling analyses conducted pursuant to the EPA’s
SO2 Data Requirements Rule (80 FR 51052, August
21, 2015) and information submitted to the EPA by
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Distance to
nearest state
(km)
SO2 emissions (tons)
2011
2017
% change
2019
2011–2019
4538011
5367811
4827111
4633811
7303711
6732411
7287311
7766111
7768011
18, Missouri ........
3, Missouri ..........
44, Missouri ........
0.5, Missouri .......
0.3, Iowa .............
0.3, Iowa .............
24, Iowa ..............
33, Iowa ..............
17, Colorado .......
243.83
17,872.15
2,792.76
5,989.47
17,334.65
14,069.34
1,067.12
1,399.76
0.62
154.51
12,639.08
1,845.46
5,332.61
16,134.40
11,244.90
1,250.77
2,231.52
222.81
157.42
619.07
295.11
904.01
15,950.20
7,896.85
694.12
926.23
221.36
133.06
719.98
471.72
1,203.00
10,386.51
5,792.82
681.44
985.08
205.93
¥45.43
¥95.97
¥83.11
¥79.91
¥40.08
¥58.83
¥36.14
¥29.63
12 33114.1
7767911
7699311
35, Wyoming ......
25, Iowa ..............
151.66
111.98
149.08
102.53
176.80
131.04
144.71
164.59
¥4.58
46.98
states, air agencies, and third party stakeholders
such as citizen groups and industry representatives.
10 This emissions trends information was derived
from the EPA’s web page https://www.epa.gov/air-
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A. Kansas
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1. State’s Analysis
In its SIP submittal, Kansas conducted
a weight of evidence analysis to
examine whether SO2 emissions from
Kansas adversely affect attainment or
maintenance of the 2010 SO2 NAAQS in
downwind states.13 Kansas evaluated
potential air quality impacts on areas
outside the state through an assessment
of whether SO2 emissions from sources
located within 50 km of Kansas’ borders
may have associated interstate transport
impacts. The State’s analysis included
SO2 emissions information in the state,
with specific focus on sources and
counties located within 50 km of
Kansas’ borders. Of the 11 facilities in
Kansas with SO2 emissions greater than
100 tpy, only four facilities are located
within 50 km of Kansas’ borders: AGC
Flat Glass (18 km from Missouri),
Evergy—La Cygne (3 km from Missouri),
Evergy—Lawrence (44 km from
Missouri), and Kansas City BPU—
Nearman (0.6 km from Missouri).
Kansas provided an in-depth analysis
for these four facilities by assessing
current permitted emissions rates and
existing control technologies. Kansas
also evaluated an additional six
facilities with SO2 emissions greater
than 10 tpy but less than 100 tpy,
located within 50 km of Kansas’
borders. Kansas also reviewed
meteorological conditions
representative of SO2 sources near the
state’s border, and the distances from
identified SO2 sources in Kansas to the
nearest area that is not attaining the
NAAQS or may have trouble
maintaining the NAAQS in another
state. Kansas also reviewed statewide
emissions and ambient air monitoring
trends. Finally, Kansas reviewed mobile
source emissions data from highway
and off-highway vehicles and
population data in all of the Kansas
counties which border other states.
Based on this weight of evidence
analysis, Kansas concluded that
emissions from sources within the state
will not contribute to nonattainment or
interfere with maintenance of the 2010
SO2 NAAQS in neighboring states.
2. The EPA’s Prong 1 Evaluation
The EPA proposes to find that Kansas’
SIP meets the interstate transport
11 Data retrieved from the EPA’s https://
www.epa.gov/air-trends/air-quality-designvalues#report.
12 The EPA notes that emissions for Clean Harbors
Environmental Services decreased by 7.5% from
2014 to 2019.
13 See Kansas’ SO interstate transport SIP as
2
submitted in January 2020 in the docket for this
action.
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requirements of CAA section
110(a)(2)(D)(i)(I), prong 1 for the 2010
SO2 NAAQS, as discussed below. To
support our proposal, we completed a
weight of evidence analysis which
considers an evaluation of ambient air
quality data and of available
information for certain emission sources
near the Kansas border, as well as
available modeling results for sources in
Kansas or neighboring states within 50
km of Kansas’ borders. Based on that
analysis, we propose to find that Kansas
will not significantly contribute to
nonattainment of the 2010 SO2 NAAQS
in any other state.
To assess ambient air quality, the EPA
reviewed monitoring data in Kansas and
neighboring states to see whether there
were any monitoring sites, particularly
near the Kansas border, with elevated
SO2 concentrations that might warrant
further investigation with respect to
interstate transport of SO2 from
emission sources in Kansas to a
neighboring state near any given
monitor. We reviewed 2017–2019 SO2
design value concentrations at monitors
with data sufficient to produce valid 1hour SO2 design values for Kansas and
neighboring states.14 In Table 2, we have
included all monitors in each
neighboring state and in Kansas within
50 km of the Kansas border. As shown,
there are no violating design values in
Kansas or neighboring states within 50
km of the state border. In Kansas’
analysis, the state reviewed its potential
impact on the existing 2010 SO2
nonattainment area in Jackson County,
Missouri, which is the only designated
nonattainment area within 50 km of
Kansas’ borders.
The data presented in Table 2 shows
that Kansas has one SO2 monitor within
50 km of its borders, in Wyandotte
County. The 2017–2019 design value for
this monitor is 6 ppb, or 8% of the 75
ppb level of the NAAQS. Two monitors
in neighboring states are located within
50 km of the Kansas border, and these
monitors recorded SO2 design values
ranging between 13% and 37% of the
level of the 2010 SO2 NAAQS. Thus,
these air quality data do not, by
themselves, indicate any particular
location that would warrant further
investigation with respect to SO2
emission sources that might
significantly contribute to
nonattainment in the bordering states.
However, because the monitoring
network is not necessarily designed 15 to
14 Id.
15 State monitoring networks must meet the
minimum monitoring requirements contained in
appendix D to 40 CFR part 58. Specifically, section
4.4 of appendix D outlines the minimum
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find all locations of high SO2
concentrations, this observation
indicates an absence of evidence of
impact at these locations but is not
sufficient evidence by itself of an
absence of impact at all locations in the
neighboring states. We have therefore
considered additional evidence to
support our conclusion that Kansas will
not significantly contribute to
nonattainment of the 2010 SO2 NAAQS
in any other state.
In the next step of our weight of
evidence analysis, the EPA evaluated
available modeling results for sources in
Kansas and in the adjacent states that
are within 50 km of the Kansas border.
The purpose for evaluating modeling for
sources in Kansas within 50 km of the
Kansas border is to determine whether
these sources are, either on their own or
in conjunction with other sources near
the border, impacting a violation of the
2010 1-hour SO2 NAAQS in another
state. The purpose of evaluating
modeling results in adjacent states
within 50 km of the Kansas border is to
ascertain whether there are any modeled
violations in neighboring states to
which sources in Kansas could
potentially be contributing.
Table 4 provides a summary of the
modeling results for two sources in
Kansas which have available modeling
information and are located within 50
km of another state: Evergy—La Cygne
Generating Station (La Cygne) and the
Board of Public Utilities Nearman Creek
Station (Nearman). The modeling
analyses resulted in no modeled
violations of the 2010 1-hour SO2
NAAQS within the modeling domain
for each facility. The emission trends for
these facilities are also provided in
Table 3, and the EPA has verified that
the most recent annual emissions are
below the annual emissions from the
years modeled at each modeled source.
The modeling submitted by Kansas in
September 2015 for La Cygne was based
on allowable emissions and resulted in
a maximum impact of 52.6 ppb or 70%
of the level of the NAAQS.16 Kansas
monitoring requirements for SO2 monitoring based
on population weighted emissions. Monitors sited
to meet the minimum monitoring requirements are
sited for a number of reasons (e.g. measuring a
source’s maximum contribution, measuring
background concentrations, monitoring population
exposure, etc.) and may not necessarily capture
maximum impacts from specific sources. However,
data from these monitors may still provide useful
evidence in the context of interstate transport.
16 See the EPA’s Technical Support Document for
its Intended Round 2 Designations for the 2010 SO2
NAAQS for Kansas available at: https://
www.epa.gov/sites/production/files/2016-03/
documents/ks-epa-tsd-r2.pdf and the EPA’s
Technical Support Document for its Final Round 2
Designations for the 2010 SO2 NAAQS for Kansas
available at: https://www.epa.gov/sites/production/
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indicated in its SIP that Evergy La
Cygne is comprised of two coal-fired
boilers, one of which is equipped with
a wet lime scrubber with a 95%
efficiency for controlling SO2
emissions.17 The emissions limits
associated with these controls were
modeled by Kansas and resulted in a
concentration gradient within the
domain that does not lead the EPA to
believe that there would be substantial
impacts beyond the modeling domain.
There are no SO2 sources in Missouri
within 50 km of La Cygne around which
the EPA would expect elevated
concentrations to which La Cygne could
contribute.
For Nearman, the EPA evaluated two
sets of available modeling results. The
first, depicted in Table 4, includes
modeling submitted by the State of
Kansas.18 That modeling was based on
actual emissions from 2012–2014 and
resulted in a maximum impact of 49.2
ppb, or 66% of the level of the NAAQS.
The second set of modeling results was
submitted by the State of Missouri and
was the basis of the clean data
determination for the Jackson County,
Missouri 1-hour SO2 nonattainment
area. That modeling, depicted in Table
5 as associated with nearby sources in
Missouri, included actual emissions for
Nearman from 2016–2018.19 This
modeling demonstrates that there are no
violations in the designated Jackson
County nonattainment area to which
Kansas sources could contribute. Kansas
explicitly reviewed the Jackson County,
Missouri, 2010 1-hour SO2
nonattainment area, as part of its
analysis and concluded that Kansas
sources do not contribute to violations
in the area as it is no longer
experiencing violations of the NAAQS.
Further, the EPA previously determined
that the Jackson County, Missouri
nonattainment area has attained the
standard and thereby the EPA agrees
with Kansas’ conclusion that there are
no violations in this area to which
Kansas sources could contribute.20
Additionally, as shown in Table 2, the
monitor in the Jackson County, Missouri
nonattainment area is currently
31649
monitoring concentrations well below
the level of the standard. Kansas
indicated in its SIP that BPU–Nearman
is comprised of two units, one of which
is equipped with a circulating dry
scrubber for SO2 control.21 BPU–
Nearman is also subject to the acid gas
emissions limit of the Mercury and Air
Toxics Standard (MATS) and opts to
meet this limit by complying with the
SO2 emissions limits spelled out in 40
CFR part 63, subpart UUUUU. Based on
the downward trend in emissions since
the modeled time period, specifically
emissions from BPU–Nearman have
decreased by approximately 80% from
2011 to 2019, the EPA finds the
available modeling to be a conservative
estimate of current actual air quality and
an indicator that the Jackson County,
Missouri area is not likely to experience
issues maintaining the standard in the
future. Additionally, it is unlikely that
the emissions from these facilities could
increase in the future to such a degree
as to significantly contribute to
nonattainment in any other state.
TABLE 4—KANSAS SOURCES WITH MODELING DATA LOCATED WITHIN 50 km OF ANOTHER STATE
2020
emissions
(tons) *
Distance from
source to
Kansas border
(km)
Kansas
source
County
La Cygne ....
Linn ............
725
2.8
Nearman .....
Wyandotte ..
1,211
0.77
Other facilities included
in modeling
None .........................................
Numerous facilities located in
Jackson County, Missouri.
Modeled 99th percentile
1-hour SO2 maximum
concentration
(ppb)
52.60 (based on allowable emissions).
49.24 (based on 2012–2014 actual emissions for all sources).
Model grid extends into
another state?
No.
Yes (into Jackson and Platte
County, Missouri).
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* Emissions data throughout this document were obtained using the EPA’s Emissions Inventory System (EIS) Gateway.
Table 5 provides a summary of the
available modeling results for sources
with annual emissions of greater than
100 tons per year based on the latest
available emissions inventory in
neighboring states which are located
within 50 km of Kansas: Evergy
Hawthorn Generating Station
(Hawthorn), Audubon Materials
(Audubon), and Empire Asbury in
Missouri, and Continental Carbon Black
Production Facility in Ponca City,
Oklahoma. As stated above, we consider
the air quality near these sources in our
analysis because, as a result of the
localized nature of SO2 as a pollutant,
it is near these sources that sources in
Kansas are more likely to contribute to
a violation of the standard.
For Hawthorn and Audubon, the EPA
similarly evaluated the modeling results
of the clean data determination
modeling for the Jackson County,
Missouri 1-hour SO2 nonattainment
area, in which actual emissions for
Hawthorn and Audubon were explicitly
included. This modeling demonstrates
that there are no violations in the
designated Jackson County
nonattainment area to which Kansas
sources could contribute.22
The modeling submitted by Missouri
for the Empire Asbury facility was based
on actual emissions and resulted in a
maximum impact of 39 ppb, or 52% of
the level of the NAAQS.23 The Empire
Asbury facility, located 2.5 km from the
Kansas border, reported zero emissions
in 2020 and officially retired in March
files/2016-07/documents/r7_ks_final_designation_
tsd_06302016.pdf.
17 Pursuant to La Cygne’s operating permit No. O–
11952 issued on May 14, 2018, units 1 and 2 are
subject to an emissions limit of 0.10 pounds per
Million British Thermal Units (lb/MMBtu) on a 30day rolling average.
18 See the EPA’s Technical Support Document for
its Intended Round 2 Designations for the 2010 SO2
NAAQS for Kansas available at: https://
www.epa.gov/sites/production/files/2016-03/
documents/ks-epa-tsd-r2.pdf and the EPA’s
Technical Support Document for its Final Round 2
Designations for the 2010 SO2 NAAQS for Kansas
available at: https://www.epa.gov/sites/production/
files/2016-07/documents/r7_ks_final_designation_
tsd_06302016.pdf.
19 For more details on the modeling
demonstration for Nearman and the nearby sources
(i.e. sources in nearby Missouri) included in the
modeling, see Determination of Attainment for the
Jackson County, Missouri 1-Hour SO2 NAAQS and
Redesignation of the Wyandotte County, Kansas
Unclassifiable Area to Attainment/Unclassifiable,
85 FR 41193, July 9, 2020.
20 See Id.
21 Pursuant to Nearman’s operating permit No. O–
14125, Unit 001 is subject to an annual SO2
emission limit of 3 lb/MMBtu [K.A.R. 28–19–31(c)
and 40 CFR 60.45(g)(2)]; 0.8 lb/MMBtu derived
from liquid fossil fuel [NSPS Subpart D40 CFR
60.43(a)(2)]; 1.2 lb/MMBtu derived from solid fossil
fuel [NSPS Subpart D40 CFR 60.43(a)(1)].
22 See Determination of Attainment for the
Jackson County, Missouri 1-Hour SO2 NAAQS and
Redesignation of the Wyandotte County, Kansas
Unclassifiable Area to Attainment/Unclassifiable,
85 FR 41193, July 9, 2020.
23 See the EPA’s Technical Support Document for
its Intended Round 3 Designations for the 2010 SO2
NAAQS for Missouri available at: https://
www.epa.gov/sites/production/files/2017-08/
documents/22_mo_so2_rd3-final.pdf and the EPA’s
Technical Support Document for its Final Round 3
Designations for the 2010 SO2 NAAQS for Missouri
available at: https://www.epa.gov/sites/production/
files/2017-12/documents/22-mo-so2-rd3-final.pdf.
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decreased from 5,893 tons in 2014 (the
highest year in the modeled period) to
2,995 tons in 2019. Additionally, the
Continental Carbon facility is located 37
km from the Kansas border and there are
no sources in Kansas within 50 km of
the Continental Carbon facility. The
most recent available annual emissions
for each source are also provided in
Table 5, and the EPA has verified that
2020.24 Additionally, there are no
Kansas sources located within 50 km of
the Empire Asbury facility. The
modeling submitted by Oklahoma for
the Continental Carbon facility in Kay,
Oklahoma was based on actual
emissions and resulted in a maximum
impact of 65.1 ppb, or 87% of the level
of the NAAQS.25 However, the
emissions for this facility have
the most recent annual emissions are
below the annual emissions from the
years modeled at each modeled source.
For these reasons, the EPA finds there
are no areas with modeled violations
within 50 km of the Kansas border to
which Kansas sources could be
contributing.
TABLE 5—OTHER STATES’ SOURCES WITH MODELING DATA LOCATED WITHIN 50 km OF KANSAS
2019
emissions
(tons)
Distance from
source to
Kansas border
(km)
Source
County
Evergy Hawthorn ....
Jackson, Missouri ..
∧ 929
9.7
Audubon Materials,
LLC Sugar Creek
Plant.
Empire Asbury ........
Jackson, Missouri ..
229
15
Jasper/Barton
Counties, Missouri.
Kay, Oklahoma ......
∧0
2.5
2,995
37
Continental Carbon
Black Production
Facility—Ponca
City Plant.
Modeled 99th percentile
1-hour SO2 maximum
concentration
(ppb)
Other facilities included
in modeling
Nearman (Wyandotte County,
Kansas); other sources <100
tons per year.
Nearman (Wyandotte County,
Kansas); other sources <100
tons per year of SO2.
Other Missouri sources <100
tons per year of SO2.
Oklahoma Gas & Electric, Sooner Generating Station (Noble
County, Oklahoma), Phillips
66 Company—Ponca City Refinery (Kay County, Oklahoma), 2 other Kay County,
Oklahoma sources <100 tons
per year of SO2.
43.47 (based on 2016–
2018 actual emissions
for all sources).
43.47 (based on 2016–
2018 actual emissions
for all sources).
39.0 (based on 2012–
2014 actual emissions
for all sources).
65.1 (based on 2012–
2014 actual emissions
for all sources).
Model grid extends into
another state?
No.
No.
Yes (into Crawford and
Cherokee Counties in
Kansas).
No.
∧ Based on 2020 emissions.
The EPA proposes to find that the
modeling results summarized in Tables
4 and 5, which provide evidence that air
quality near certain larger sources in
other states is attaining the NAAQS,
when weighed along with the other
factors in this document, support the
EPA’s proposed conclusion that sources
in Kansas will not significantly
contribute to nonattainment of the 2010
1-hour SO2 NAAQS in any other state.
The next step in our weight of
evidence analysis is to assess certain
other sources near the border for which
we do not have available modeling or
monitoring data. As noted in Section III
of this document, the EPA finds that it
is appropriate to examine the impacts of
emissions from stationary sources in
Kansas in distances ranging from 0 km
to 50 km from the facility, based on the
‘‘urban scale’’ definition contained in
appendix D to 40 CFR part 58, section
4.4. Kansas assessed point sources up to
50 km from state borders to evaluate
trends and SO2 concentrations in areawide air quality. The list of sources
emitting 100 tpy 26 or more of SO2
within 50 km from state borders without
available modeling data, is shown in
Table 6.
TABLE 6—KANSAS SO2 SOURCES WITH NO AVAILABLE MODELING DATA NEAR NEIGHBORING STATES
Kansas source
2019 SO2
emissions
(tons)
Facility ID
AGC Flat Glass .................................
Evergy Lawrence ..............................
4538011
4827111
Distance to
Kansas border
(km)
133.1
∧ 225.5
19
44
Distance to nearest neighboring
state SO2 source
(km)
50 (Evergy Hawthorn) ......................
55 (Evergy Iatan) .............................
Neighboring
state source
2019
emissions
(tons) ∧
∧ 929
∧ 812
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∧ Based on 2020 emissions.
Table 6 shows the distance from the
sources listed therein to the nearest outof-state source emitting above 100 tpy of
SO2, because elevated levels of SO2, to
which SO2 emitted in Kansas may have
a downwind impact, are most likely to
be found near such sources. As shown
in Table 6, the distance between the
sources in Kansas and the nearest
24 In a letter dated December 3, 2019, from Liberty
Utilities to the State of Missouri, Liberty Utilities
requested that all air permits for the Empire Asbury
facility become void on the permanent retirement
date of March 1, 2020. This letter is included in the
docket for this action.
25 See the EPA’s Technical Support Document for
its Intended Round 3 Designations for the 2010 SO2
NAAQS for Oklahoma available at: https://
www.epa.gov/sites/production/files/2017-12/
documents/33-ok-so2-rd3-final.pdf and the EPA’s
Technical Support Document for its Final Round 3
Designations for the 2010 SO2 NAAQS for
Oklahoma available at: https://www.epa.gov/sites/
production/files/2017-12/documents/33-ok-so2-rd3final.pdf.
26 Kansas limited its analysis to Kansas sources of
SO2 emitting at least 100 tpy. We agree with Kansas’
choice to limit its analysis in this way, because in
the absence of special factors, for example the
presence of a nearby larger source, a high
concentration of smaller sources in an area, or
unusual physical factors, Kansas sources emitting
less than 100 tpy can appropriately be presumed to
not be causing or contributing to SO2
concentrations above the NAAQS.
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sources emitting over 100 tpy in
Missouri is greater than or equal to 50
km. Additionally, Kansas evaluated the
current operations and control
equipment at the AGC Flat Glass and
Evergy Lawrence facilities. In its SIP,
Kansas indicated that the AGC Flat
Glass facility operates a glass melting
furnace which is equipped with dry
sorbent injection for control of SO2.27
The Evergy Lawrence facility is
comprised of two units which are both
equipped with high-efficiency scrubbers
for SO2 control.28 Kansas evaluated
available meteorological data to
determine the wind patterns near AGC
Flat Glass and Evergy Lawrence. Kansas
included wind roses for the Olathe
Johnson County airport that depict the
predominant wind pattern in the area as
being from the South-Southwest
blowing emissions from AGC Flat Glass
away from Missouri.29 Kansas included
wind roses for the Lawrence Municipal
airport that depict the predominant
wind pattern in the area as being from
the South-Southeast blowing emissions
from Evergy Lawrence away from the
Jackson County nonattainment area.30
Given the large distance between the
cross-state sources, the localized nature
of SO2, and the wind rose analysis
provided by Kansas, the EPA agrees it
is unlikely that emissions from AGC
Flat Glass or Evergy Lawrence in Kansas
could interact with emissions from
Evergy Hawthorn or Evergy Iatan in
Missouri in such a way as to cause a
violation of the NAAQS in Missouri.
Additionally, based on the distance
from the Kansas sources to the border
and the overall wind patterns in the
area, the EPA finds it unlikely that the
sources in Kansas could on their own
cause a violation in Missouri.
The EPA also reviewed the location of
sources for which modeling information
was not available in neighboring states
emitting more than 100 tpy of SO2 and
located within 50 km of the Kansas
border, as shown in Table 7. This is
because elevated levels of SO2, to which
SO2 emitted in Kansas may have a
downwind impact, are most likely to be
found near such sources.
TABLE 7—NEIGHBORING STATE SO2 SOURCES WITH NO AVAILABLE MODELING DATA NEAR KANSAS *
Source
Facility ID
Evergy Iatan Generating Station (Missouri) ....................
Exide Technologies Canon Hollow (Missouri) ................
2019 SO2
emissions
(tons)
Distance to
Kansas border
(km)
∧ 811.6
158.5
6795111
331492
0.7
7.1
Distance to nearest Kansas
SO2 source
(km)
39 (Kansas City BPU-Nearman) .......
106 (Kansas City BPU-Nearman) .....
Kansas source
2020 emissions
(tons)
1,211
1,211
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* We have not included sources that are duplicative of those in Table 6.
∧ Based on 2020 emissions.
As shown in Table 7, the shortest
distance between any pair of these
sources is 39 km (between Evergy Iatan
in Missouri and Nearman in Kansas).
The available modeling data for the
Nearman facility, referenced in Tables 4
and 5, indicates that Nearman does not
significantly contribute to violations in
nearby areas in Missouri as there are no
modeled violations in Missouri. Kansas
evaluated available meteorological data
to determine the wind patterns near
Nearman. Kansas included wind roses
for the Kansas City downtown airport
that depict the predominant wind
pattern in the area around Nearman as
being from the South-Southwest
blowing emissions from Nearman away
from the Jackson County nonattainment
area.31 Additionally, based on the
distance between cross-state sources as
well as the overall wind patterns in the
area as referenced by Kansas, the EPA
agrees that it is unlikely that emissions
from Nearman could interact with
emissions from Every Iatan or Exide
Technologies in such a way as to cause
a violation in Missouri.
Kansas also evaluated two sources
located within 50 km of its borders that
emitted above 80 tpy but below 100 tpy.
The CRNF-Coffeyville and CRRM-
Refinery facilities are each located 5 km
from the Kansas border with Oklahoma.
CRNF-Coffeyville emitted 83 tons of SO2
in 2018. CRRM-Refinery emitted 93 tons
of SO2 in 2018. There are no sources in
Oklahoma within 50 km of these
sources such that their emissions could
interact to impact a violation of the
NAAQS. Kansas also included wind
roses for the Coffeyville Municipal
airport that depict the predominant
wind pattern in the area as being from
the South blowing emissions from the
Kansas sources away from Oklahoma
and further into Kansas.32 Given the
localized nature of SO2 and the overall
wind pattern in the area as referenced
by Kansas, the EPA agrees it is unlikely
that the CRNF-Coffeyville and CRRMRefinery facilities could on their own
cause or contribute to a violation in the
nearby State of Oklahoma.
This information together with the
localized range of potential 1-hour SO2
impacts indicates that there are no
additional locations in neighboring
states that would warrant further
investigation with respect to Kansas SO2
emission sources that might contribute
to problems with attainment of the 2010
SO2 NAAQS.
Kansas also included information on
mobile source emissions and population
in its border counties. Kansas indicated
that SO2 emissions from mobile sources
are controlled through federally
mandated fuel standards which limit
sulfur concentrations at the refinery
level. Kansas notes that mobile
emissions are disbursed in small
quantities over large geographic areas
leading to greater dispersion before
crossing state borders. Additionally,
Kansas expects further reductions in
SO2 emissions from this sector as the
EPA continues to regulate emissions
from mobile sources along with regular
fleet turnover to cleaner vehicles. The
EPA agrees that because emissions from
non-point sources in other source
categories such as mobile emissions are
more dispersed throughout the State,
emissions from other source categories
such as mobile sources are less likely to
cause high ambient concentrations
when compared to a point source on a
ton-for-ton basis.
In conclusion, for interstate transport
prong 1, we reviewed ambient SO2
monitoring data and available
information for SO2 emission sources
within 50 km of the Kansas border, as
well as available modeling results for
27 Pursuant to AGC’s operating permit No. O–
10871, unit EU–001 is subject to an SO2 emission
limit of 2.2 lb of SO2 per ton of glass produced on
a 30-day rolling average, and 262.8 tons of SO2
emissions per rolling consecutive 12-month period.
28 Pursuant to Evergy Lawrence’s operating
permit No. O–11856 issued on February 14, 2018,
units 4 and 5 are subject to an emissions limit of
0.15 lb/MMBtu on a 30-day rolling average.
29 See Chapter 3 of Kansas’ SO Transport SIP
2
Submittal included in the docket for this action for
the wind rose graphics referenced by Kansas.
30 See id.
31 See Id.
32 See Id.
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sources in Kansas and in adjacent states
within 50 km of the Kansas border.
Based on this analysis, we propose to
determine that Kansas will not
significantly contribute to
nonattainment of the 2010 SO2 NAAQS
in any other state, per the requirements
of CAA section 110(a)(2)(D)(i)(I).
3. The EPA’s Prong 2 Evaluation
In its prong 2 analysis, Kansas
reviewed potential SO2 impacts on
designated maintenance areas. The EPA
interprets CAA section 110(a)(2)(D)(i)(I)
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, rather than
only former nonattainment, and thus
current maintenance, areas. Kansas also
performed a prong 2 analysis based on
the EPA’s interpretation, noting that
monitors located near Kansas in
neighboring states showed very low
levels of SO2, emissions in Kansas and
neighboring states have decreased
indicating they should not be
considered to have maintenance issues
for this NAAQS. Kansas also referenced
federal regulations which have resulted
in and will continue to result in SO2
emissions decreases in Kansas and
neighboring states.
The EPA has reviewed Kansas’
analysis and other available information
on SO2 air quality, including federally
enforceable regulations and emission
trends to evaluate the state’s conclusion
that Kansas will not interfere with
maintenance of the 2010 SO2 NAAQS in
downwind states. This evaluation
builds on the analysis regarding
significant contribution to
nonattainment (prong 1), which
evaluated monitored ambient
concentrations of SO2 in Kansas and
neighboring states, available modeling
results, and the large distances between
cross-state SO2 sources, the EPA is
proposing to find that SO2 levels in
neighboring states near the Kansas
border do not indicate any inability to
maintain the SO2 NAAQS that could be
attributed in part to sources in Kansas.
As shown in Table 1, the statewide SO2
emissions from Kansas and neighboring
states have decreased substantially over
time, per our review of the EPA’s
emissions trends data.33 From 2000 to
2019, total statewide SO2 emissions
decreased by the following proportions:
Colorado (85% decrease), Kansas (83%
decrease), Missouri (72% decrease),
Nebraska (40% decrease), and
33 Additional emissions trends data are available
at: https://www.epa.gov/air-emissions-inventories/
air-pollutant-emissions-trends-data.
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Oklahoma (68% decrease). This trend of
decreasing SO2 emissions does not by
itself demonstrate that areas in Kansas
and neighboring states will not have
issues maintaining the 2010 SO2
NAAQS. However, as a piece of this
weight of evidence analysis for prong 2,
it provides further indication (when
considered alongside low monitor
values in neighboring states as depicted
in Table 2) that such maintenance issues
are unlikely. This is because the
geographic scope of these reductions
and their large sizes strongly suggest
that they are not transient effects from
reversible causes, and thus these
reductions suggest that there is very low
likelihood that a strong upward trend in
emissions will occur that might cause
areas presently in attainment to violate
the NAAQS. These reductions have
been caused by regulatory requirements
in Kansas and the downwind states and
by economic factors, such as low natural
gas prices and the increasing supply of
renewable energy, that are not likely to
be reversed.34
Kansas also identified EPA programs
which, either directly or indirectly, have
significantly reduced SO2 emissions in
Kansas. These programs include: The
Acid Rain program; the Cross-State Air
Pollution Rule (CSAPR); Prevention of
Significant Deterioration (PSD)/New
Source Review (NSR) Permitting
Programs; Heavy-Duty Diesel Rule;
Mercury and Air Toxic Standards Rule
(MATS); 35 Regional Haze; 36 Nonroad
Diesel Rule; and the EPA’s Tier 2 Motor
Vehicle Emissions Standards and
Gasoline Sulfur Control Requirements
Rule. The EPA agrees that the federal
regulations identified by Kansas have
helped to reduce SO2 emissions from
various sources in Kansas in addition to
other federal regulations as detailed
here. The EPA’s Acid Rain Program set
a permanent cap on the total amount of
SO2 that may be emitted by electric
generating units (EGUs) in the
contiguous United States.37 CSAPR
requires significant reductions in SO2
emissions from power plants in the
eastern half of the United States,
including Kansas and neighboring
states.38 MATS requires reductions of
emissions of heavy metals which, as a
co-benefit, reduce emissions of SO2, and
establishes alternative numeric emission
standards, including SO2 (as an
34 Kansas provided information on emission
reductions and control equipment for certain
sources in its SIP and the EPA summarized this
information in its prong 1 analysis.
35 See 77 FR 9304.
36 See 64 FR 35714.
37 See 40 CFR parts 72 through 78.
38 See 40 CFR part 97. See also 76 FR 48208.
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alternate to hydrochloric acid).39 The
EPA’s Nonroad Diesel Rule will reduce
sulfur levels from about 3,000 parts per
million (ppm) to 15 ppm when fully
implemented.40 The EPA’s Heavy-Duty
Engine and Vehicle Standards and
Highway Diesel Fuel Sulfur Control
Requirements (Heavy-Duty Diesel Rule)
required refiners to start producing
diesel fuel for use in highway vehicles
with a sulfur content of no more than
15 ppm as of June 1, 2006.41 NSPS for
various source categories, including but
not limited to Industrial-CommercialInstitutional Steam Generating Units; 42
Sulfuric Acid Plants; 43 Stationary Gas
and Combustion Turbines; 44 Portland
Cement Manufacturing; 45 Electric
Utility Steam Generating Units
(Boilers); 46 and Onshore Natural Gas
Processing,47 establish standards which
reduce SO2 emissions.
In addition, the EPA’s Tier 3 Motor
Vehicle Emission and Fuel Standards
Rule 48 also reduce SO2 emissions by
establishing gasoline sulfur standards
that reduce SO2 emissions from certain
types of mobile sources. The EPA finds
that these federal measures have and
continue to lower SO2 emissions,
which, in turn, are expected to continue
to support the EPA’s proposed
conclusion that SO2 emissions from
Kansas will not contribute significantly
to nonattainment or interfere with
maintenance of the 2010 1-hour SO2
NAAQS in another state.
As noted in Kansas’ submission, any
future large sources of SO2 emissions
will be addressed by Kansas’ SIPapproved Prevention of Significant
Deterioration (PSD) program.49 Future
minor sources of SO2 emissions will be
addressed by Kansas’ minor new source
review permit program.50 The
permitting regulations contained within
these programs should help ensure that
39 See 40 CFR parts 60 and 63. See also 77 FR
9304.
40 See 40 CFR parts 9, 69, 80, 86, 89, 94, 1039,
1048, 1051, 1065, and 1068. See also 69 FR 38958.
41 See 40 CFR parts 69, 80, and 86. See also 66
FR 5002.
42 See 40 40 CFR part 60, subpart Da and 40 CFR
part 63. See also 77 FR 9304.
43 See 40 CFR part 60, subparts A, D, E, F, G and
H. See also 36 FR 24876.
44 See 40 CFR part 60, subparts GG and KKKK.
See also 71 FR 38482 and 44 FR 52792
45 See 40 CFR parts 60 and 63. See also 75 FR
54970.
46 See 40 CFR part 60, subpart Da and 40 CFR part
63. See also 77 FR 9304.
47 See 40 CFR part 60, subpart LLL. See also 77
FR 49490.
48 See 40 CFR parts 79, 80, 85, 86, 600, 1036,
1037, 1039, 1042, 1048, 1054, 1065, and 1066. See
also 79 FR 23414.
49 See EPA’s final action of the PSD portions of
Kansas’ SIP, at 80 FR 32017, June 4, 2015.
50 Id.
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ambient concentrations of SO2 in
neighboring states are not exceeded as a
result of new facility construction or
modification occurring in Kansas.
As previously mentioned, Kansas
evaluated its potential impacts to the
Jackson County, Missouri
nonattainment area located near the
Kansas border. As discussed in the
EPA’s prong 1 analysis, the modeling for
the Jackson County area’s clean data
determination included sources in
Kansas and did not show substantial
impacts from Kansas sources to the
Missouri area. Additionally, the EPA
has determined the area attained the
NAAQS through a clean data
determination with the monitor in the
area still showing values well below the
level of the standard. For these reasons,
the EPA finds that emissions from
Kansas do not interfere with
maintenance of the NAAQS in the
Jackson County area as the area is not
exhibiting difficulties in maintaining
the standard.
In conclusion, for interstate transport
prong 2, we reviewed additional
information about SO2 air quality and
emission trends and Kansas’ permitting
regulations, as well as the technical
information considered for interstate
transport prong 1. We find that the
combination of low ambient
concentrations of SO2 in Kansas and
neighboring states, the available
modeling results, the large distances
between cross-state SO2 sources, the
downward trend in SO2 emissions from
Kansas and neighboring states, and state
measures that prevent new facility
construction or modification in Kansas
from causing SO2 exceedances in
downwind states, indicates no
interference with maintenance of the
2010 SO2 NAAQS in other states.
Accordingly, we propose to determine
that Kansas SO2 emission sources will
not interfere with maintenance of the
2010 SO2 NAAQS in any other state, per
the requirements of CAA section
110(a)(2)(D)(i)(I).
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B. Nebraska
1. State’s Analysis
In its SIP, Nebraska conducted a
weight of evidence analysis to examine
whether SO2 emissions from Nebraska
adversely affect attainment or
maintenance of the 2010 SO2 NAAQS in
downwind states.51 Nebraska evaluated
potential air quality impacts on areas
outside the state through an assessment
of whether SO2 emissions from sources
located within 50 km of Nebraska’s
51 See Nebraska’s SO interstate transport SIP as
2
submitted in October 2020 in the docket for this
action.
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borders may have associated interstate
transport impacts. The State’s analysis
included SO2 emissions information in
the state, with specific focus on sources
and counties located within 50 km of
Nebraska’s borders. For the seven
sources which emitted greater than 100
tons per year of SO2 located within 50
km of Nebraska’s borders, Nebraska
provided an in-depth analysis by
assessing current permitted emissions
rates and existing control technologies.
Nebraska also reviewed meteorological
conditions representative of SO2 sources
near the state’s border, and the distances
from identified SO2 sources in Nebraska
to the nearest area that is not attaining
the NAAQS or may have trouble
maintaining the NAAQS in another
state. Nebraska also reviewed statewide
emissions and ambient air monitoring
trends. Based on this weight of evidence
analysis, Nebraska concluded that
emissions within the state will not
contribute to nonattainment or interfere
with maintenance of the 2010 SO2
NAAQS in neighboring states. Nebraska
also noted that SO2 emissions within
the state have been steadily decreasing
over time, specifically noting a 49.7%
decrease in point source emissions
between 2006 and 2019. With regard to
the interference with maintenance
requirement, Nebraska discussed the
low monitored ambient concentrations
of SO2 in neighboring states in the
period up to and including 2019. Based
on this weight of evidence analysis,
Nebraska concluded that emissions
within the state will not significantly
contribute to nonattainment or interfere
with maintenance of the 2010 SO2
NAAQS in neighboring states.
2. The EPA’s Prong 1 Evaluation
The EPA proposes to find that
Nebraska’s SIP meets the interstate
transport requirements of CAA section
110(a)(2)(D)(i)(I), prong 1 for the 2010
SO2 NAAQS, as discussed below. To
support our proposal, we completed a
weight of evidence analysis which
considers an evaluation of ambient air
quality data and of available
information for certain emission sources
near the Nebraska border, as well as
available modeling results for sources in
Nebraska or neighboring states within
50 km of Nebraska’s borders. Based on
that analysis, we propose to find that
Nebraska will not significantly
contribute to nonattainment of the 2010
SO2 NAAQS in any other state.
To assess ambient air quality, the EPA
reviewed monitoring data in Nebraska
and neighboring states to see whether
there were any monitoring sites,
particularly near the Nebraska border,
with elevated SO2 concentrations that
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31653
might warrant further investigation with
respect to interstate transport of SO2
from emission sources in Nebraska to a
neighboring state near any given
monitor. We reviewed 2017–2019 SO2
design value concentrations at monitors
with data sufficient to produce valid 1hour SO2 design values for Nebraska
and neighboring states.52 In Table 2, we
have included all monitors in each
neighboring state and in Nebraska
within 50 km of the Nebraska border. As
shown, there are no violating design
values at monitors in Nebraska or
neighboring states within 50 km of the
state border. One area bordering
Nebraska—Woodbury County, Iowa—
has been designated unclassifiable.
Later in this section, the EPA discusses
modeling available for Woodbury
County, Iowa (See Table 10). There are
no other areas designated as
unclassifiable located within 50 km of
Nebraska’s borders. For these reasons
and for reasons discussed later in this
section, the EPA is proposing to find
that emissions from Nebraska will not
contribute significantly to
nonattainment in any other state.
The data presented in Table 2 show
that there are three Nebraska monitors
located within 50 km of a neighboring
state’s border, and these monitors
indicate design values between 32% to
55% of the NAAQS. One SO2 monitor
was installed in Nebraska as a sourceoriented monitor (AQS Site ID:
310550057) and was sited to
characterize the Omaha Public Power
District’s (OPPD) North Omaha Station
(North Omaha), which is located in
Douglas County, Nebraska and is within
50 km of the Nebraska border with Iowa.
The EPA designated Douglas County as
attainment/unclassifiable as part of the
Round 4 designations for the 2010 1hour NAAQS.53 Table 8 provides the 3year design value used to characterize
the impacts from North Omaha. The
2017–2019 design value is 34 ppb,
which is 45% of the 2010 SO2 NAAQS
and provides evidence that there is not
an air quality problem around the North
Omaha facility. Therefore, it is unlikely
that the North Omaha facility could
significantly contribute to
nonattainment of the 2010 1-hour SO2
NAAQS in the nearby State of Iowa. In
its SIP, Nebraska noted that the North
Omaha facility currently operates two
coal-fired units, using low-sulfur coal;
52 Id.
53 See TSD Chapter 2: Final Round 4 Area
Designations for the 2010 1-Hour SO2 Primary
National Ambient Air Quality Standard for Areas
without Violating Monitors, at https://
www.epa.gov/sites/production/files/2020-12/
documents/02-rd4_so2d_tsd_for_areas_without_
violating_monitors.pdf.
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located in Omaha (as shown in Table 2)
between the North Omaha facility and
the Walter Scott Jr. facility in Iowa that
similarly support the claim that the
North Omaha facility is not causing or
contributing to violations of the NAAQS
in Iowa.54 The North Omaha facility was
also included in a modeling
these units are to be converted to
natural gas by 2023. Three coal-fired
units were retired in 2016 which
resulted in a significant SO2 emissions
decrease in that year. The emissions
trends for this source are shown in
Table 3. Nebraska also referenced the
low design values at the monitors
demonstration for a nearby Iowa source.
That modeling is discussed later in this
section and provides further evidence
that there are no violations in Iowa to
which the North Omaha facility could
contribute.
TABLE 8—NEBRASKA SOURCES WITH A SOURCE-ORIENTED MONITOR WITHIN 50 KM OF ANOTHER STATE
Nebraska source
County
2020
emissions
(tons)
OPPD North Omaha .................................
Douglas ..............................
5,447
There is one monitor in a neighboring
state located within 50 km of the
Nebraska border, in Sioux City, South
Dakota, and this monitor recorded an
SO2 design value of 3 ppb, or 4% of the
2010 SO2 NAAQS. Thus, these air
quality data do not, by themselves,
indicate any particular location that
would warrant further investigation
with respect to SO2 emission sources
that might significantly contribute to
nonattainment in the bordering states.
However, because the monitoring
network is not necessarily designed 55 to
find all locations of high SO2
concentrations, this observation
indicates an absence of evidence of
impact at these locations but is not
sufficient evidence by itself of an
absence of impact at all locations in the
neighboring states. We have therefore
also conducted a source-oriented
analysis.
In the next step of our weight of
evidence analysis, the EPA evaluated
available modeling results for sources in
Nebraska and in the adjacent states that
Distance from
source to
Nebraska/Iowa
border
(km)
0.3
are within 50 km of the Nebraska
border. The purpose of evaluating
modeling for sources in Nebraska within
50 km of the Nebraska border is to
determine whether these sources are,
either on their own or in conjunction
with other sources near the border,
impacting a violation of the 2010 1-hour
SO2 NAAQS in another state. The
purpose of evaluating modeling results
in adjacent states within 50 km of the
Nebraska border is to ascertain whether
there are any modeled violations in
neighboring states to which sources in
Nebraska could potentially be
contributing.
Table 9 provides a summary of the
modeling results for one source in
Nebraska for which we have available
modeling information and is located
within 50 km of another state: Omaha
Public Power District’s (OPPD) Nebraska
City Station (Nebraska City).56 The
modeling analysis for Nebraska City
resulted in no modeled violations of the
2010 1-hour SO2 NAAQS within the
modeling domain. The emissions trends
Site ID
2017–2019
monitor 3-year
design value
(ppb)
310550057
34
for this source are included in Table 3.
The most recent available annual
emissions at Nebraska City are also
provided in Table 9, and the EPA has
verified that the most recent annual
emissions are below the annual
emissions from the years modeled for
Nebraska City. The nearest source in a
neighboring state emitting greater than
100 tpy is the Walter Scott Jr., Energy
Center, located 66 km North of Nebraska
City. In its SIP, Nebraska indicated that
Nebraska City is comprised of two coalfired units, one of which (Unit 2) is
fitted with a dry flue gas desulfurization
(scrubber) system to control SO2
emissions. Emissions at Nebraska City
have decreased approximately 36%
from 2014. Based on the large distance
between cross-state sources, the
localized nature of SO2, and the
available modeling information, the
EPA agrees that Nebraska City is not
likely contributing to violations in Iowa
as there are no modeled air quality
violations in Iowa.
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TABLE 9—NEBRASKA SOURCE WITH MODELING DATA LOCATED WITHIN 50 KM OF ANOTHER STATE
Nebraska source
County
OPPD Nebraska City .....
Otoe ............
2020
emissions
(tons)
11,480
54 For locations of monitors in relation to the
sources in Nebraska and Iowa, please see map on
page 21 of Nebraska’s SIP as contained in the
docket for this action.
55 State monitoring networks must meet the
minimum monitoring requirements contained in
appendix D to 40 CFR part 58. Specifically, section
4.4 of appendix D outlines the minimum
monitoring requirements for SO2 monitoring based
on population weighted emissions. Monitors sited
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Distance from
source to
Nebraska border
(km)
0.62
Other
facilities
included in
modeling
None ...........
Modeled 99th
percentile 1-hour SO2
maximum concentration
(ppb)
32.7 (based on 2012–
2014 actual emissions).
to meet the minimum monitoring requirements are
sited for a number of reasons (e.g., measuring a
source’s maximum contribution, measuring
background concentrations, monitoring population
exposure, etc.) and may not necessarily capture
maximum impacts from specific sources. However,
data from these monitors may still provide useful
evidence in the context of interstate transport.
56 See the EPA’s Technical Support Document for
its Intended Round 2 Designations for the 2010 SO2
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Model grid extends into
another state?
Yes (Fremont County,
Iowa).
NAAQS for Nebraska available at: https://
www.epa.gov/sites/production/files/2016-03/
documents/ne-epa-tsd-r2.pdf and the EPA’s
Technical Support Document for its Final Round 2
Designations for the 2010 SO2 NAAQS for Nebraska
available at: https://www.epa.gov/sites/production/
files/2016-07/documents/r7_ne_final_designation_
tsd_06302016.pdf.
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Table 10 provides a summary of the
available modeling results for the
modeled sources in neighboring states
which are located within 50 km of
Nebraska: Mid-American Energy—
George Neal North (George Neal North),
Mid-American Energy George Neal
South (George Neal South) and MidAmerican Energy Walter Scott Jr. Energy
Center (Walter Scott Jr.) in Iowa. The
Round 2 1-hour SO2 designations
modeling for Woodbury County, Iowa
explicitly included George Neal North
and George Neal South and no other
SO2 sources in the area, and included
portions of Nebraska in the modeling
domain.57 In 2016, the EPA designated
Woodbury County, Iowa as
unclassifiable, because even though the
modeling demonstrated attainment for
the area, some emission rates used in
the modeling analysis, specifically the
emission rates for MidAmerican Energy
Company’s George Neal North Units 1
and 2 were not yet federally enforceable
at the time of the final Round 2
designations (in June 2016). In
September 2016, Iowa rescinded the
permits for George Neal North Units 1
and 2 as they were permanently
retired.58 Therefore, the EPA can
consider the Round 2 modeling
demonstration for the purpose of
evaluating potential transport as the
emissions rates assumed in the
modeling have since become federally
enforceable.59 The North Omaha Station
is located over 100 km from the George
Neal facilities in Iowa. Specifically,
there are no sources of SO2 emitting
over 10 tpy in Nebraska located within
50 km of George Neal North and George
Neal South, providing further evidence
that Nebraska emissions are not causing
or contributing to violations in
Woodbury County, Iowa.
The modeling submitted by Iowa for
Walter Scott Jr. in Pottawattamie County
based on a set of hybrid (i.e., a mix of
allowable and 2012–2014 actual)
emissions for Walter Scott Jr. and the
OPPD North Omaha Station located in
Nebraska resulted in a maximum impact
of 51.1 ppb, or 68% of the level of the
NAAQS.60 The modeling demonstrates
maximum impacts below the level of
the NAAQS and thereby provides
evidence that Nebraska emissions are
not causing or contributing to violations
in the area of Pottawattamie County,
Iowa around Walter Scott Jr. As
depicted in Figure 19 of the EPA’s
Technical Support Document for its
Intended Round 3 Designations for the
2010 SO2 NAAQS for Iowa, the
maximum modeled impact is located to
the Southeast of the Walter Scott Jr.
facility.61 The North Omaha Station is
located approximately 19 km from the
Walter Scott Jr. facility. As previously
mentioned, Nebraska also referenced the
low design values at the monitors
located in Omaha (as shown in Table 2)
between the North Omaha facility and
the Walter Scott Jr. facility in Iowa that
similarly support the claim that the
North Omaha facility is not causing or
contributing to violations of the NAAQS
in Iowa.62 Based on the distance
between cross-state sources, the
localized nature of SO2 and the
available modeling and monitoring
information for the area, the EPA agrees
that the North Omaha Station is not
likely to cause or contribute to
violations in Iowa as there are no air
quality violations in the nearby area in
Iowa.
The most recent available annual
emissions of these identified sources in
nearby states are also provided in Table
10, and the EPA has verified that the
most recent annual emissions are below
the annual emissions from the years
modeled at each source.63
TABLE 10—OTHER STATES’ SOURCES WITH MODELING DATA LOCATED WITHIN 50 KM OF NEBRASKA
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Other state source
2020
emissions
(tons)
County
Distance from
source to
Nebraska border
(km)
Modeled 99th
percentile 1-hour
SO2 maximum
concentration
(ppb)
Other facilities
included in
modeling
George Neal North
Woodbury, Iowa .....
1,660
0.2
George Neal South
(Iowa).
74.3 (Allowable
Emissions).
George Neal South
Woodbury, Iowa .....
1,203
0.8
George Neal North
(Iowa).
74.3 (Allowable
Emissions).
Walter Scott Jr. .......
Pottawattamie, Iowa
5,960
0.1
OPPD North
Omaha (Nebraska).
51.1 (Hybrid of Actual and Allowable Emissions
for 2012–2014).
Model grid extends
into another state?
Yes (Dakota and
Thurston Counties, Nebraska).
Yes (Dakota and
Thurston Counties, Nebraska).
Yes (Douglas and
Sarpy Counties,
Nebraska).
The EPA proposes to find that the
modeling results summarized in Tables
9 and 10, which provide evidence that
air quality near certain larger sources in
other states is attaining the NAAQS,
when weighed along with the other
factors in this document, support the
EPA’s proposed conclusion that sources
in Nebraska will not significantly
57 See the EPA’s Technical Support Document for
its Intended Round 2 Designations for the 2010 SO2
NAAQS for Iowa available at: https://www.epa.gov/
sites/production/files/2016-03/documents/ia-epatsd-r2.pdf and the EPA’s Technical Support
Document for its Final Round 2 Designations for the
2010 SO2 NAAQS for Iowa available at: https://
www.epa.gov/sites/production/files/2016-07/
documents/r7_ia_final_designation_tsd_
06302016.pdf.
58 See docket document containing letter from
MidAmerican Energy dated April 18, 2016,
requesting the permits for George Neal North Units
1 and 2 be rescinded and Iowa’s response letter
dated September 9, 2016, indicating the permits for
these units were revoked.
59 The modeling for the George Neal facilities
resulted in a maximum impact near the level of the
NAAQS; however, because this modeling was based
on maximum allowable emissions prior to the
shutdown of Units 1 and 2 and included a
background concentration, the EPA finds this to be
a conservative estimate of actual air quality in the
Woodbury County area not an indication of
potential air quality issues to which Nebraska
sources could contribute.
60 See the EPA’s Technical Support Document for
its Intended Round 3 Designations for the 2010 SO2
NAAQS for Iowa available at: https://www.epa.gov/
sites/production/files/2017-08/documents/14_ia_
so2_rd3-final.pdf and the EPA’s Technical Support
Document for its Final Round 3 Designations for the
2010 SO2 NAAQS for Iowa available at: https://
www.epa.gov/sites/production/files/2017-12/
documents/14-ia-so2-rd3-final.pdf.
61 See Id.
62 For locations of monitors in relation to the
sources in Nebraska and Iowa, please see map on
page 21 of Nebraska’s SIP as contained in the
docket for this action.
63 Nebraska also included emissions trends for
certain sources in neighboring states in Table 5 of
its SIP which depicts the downward trend in
emissions at these sources as well. See Nebraska’s
SIP submittal included in the docket for this action.
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is appropriate to examine the impacts of
emissions from stationary sources in
Nebraska in distances ranging from 0
km to 50 km from the facility, based on
the ‘‘urban scale’’ definition contained
in appendix D to 40 CFR part 58, section
4.4. Nebraska assessed point sources up
contribute to nonattainment of the 2010
1-hour SO2 NAAQS in any other state.
The next step in our weight of
evidence analysis, is to assess certain
other sources near the border for which
we do not have available modeling or
monitoring data. As noted in section III
of this document, the EPA finds that it
to 50 km from neighboring state borders
to evaluate trends and SO2
concentrations in area-wide air quality
The list of sources emitting 100 tpy 64 or
more of SO2 within 50 km from state
borders without available modeling data
is shown in Table 11.
TABLE 11—NEBRASKA SO2 SOURCES WITHOUT AVAILABLE MODELING DATA NEAR NEIGHBORING STATES
Nebraska source
2019 SO2
emissions
(tons)
Facility ID
Distance to
Nebraska
border
(km)
Clean Harbors Environmental
Services, Inc.
Western Sugar Cooperative ..
7768011
205.9
15
7767911
144.7
35
Ash Grove Cement Co ..........
7287311
681.4
24
Douglas Co Recycling Landfill.
Lon D Wright Power Plant ....
7699311
164.6
25
7766111
∧587.9
33
Distance to nearest neighboring state
SO2 source
(km)
95 (HollyFrontier Cheyenne Refinery, Wyoming).
107 (Basin Electric Power Cooperative—
Laramie River Station, Wyoming).
33 (MidAmerican Energy Co.—Walter Scott
Jr., Iowa).
41 (MidAmerican Energy Co.—Walter Scott
Jr., Iowa).
59 (MidAmerican Energy Co.—Walter Scott
Jr., Iowa).
Neighboring
state source
2019
emissions
(tons)
174.7
∧5261
∧5960
∧5960
∧5960
∧ Based on 2020 emissions.
TABLE 12—NEIGHBORING STATE SO2 SOURCES NEAR NEBRASKA *
Source
2019 SO2
emissions
(tons)
Facility ID
Exide Technologies Canon Hollow
(Missouri).
8230311
Distance to
Nebraska
border
(km)
158.5
7.2
Distance to nearest Nebraska
SO2 source
(km)
80 (OPPD Nebraska City Station) ...
Nebraska
source 2020
emissions
(tons)
11,480
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* Table 12 does not include sources duplicative of Table 11.
As shown, there are two Nebraska
sources (Ash Grove Cement Company
and Douglas County Recycling Landfill)
located within 50 kilometers of a crossstate source, MidAmerican Energy Co.—
Walter Scott Jr., located in the State of
Iowa. As previously discussed and
shown in Table 10, modeling submitted
to the EPA by the State of Iowa for the
Pottawattomie County area, containing
Walter Scott Jr., indicates that the
highest predicted 99th percentile daily
maximum 1-hour concentration within
the modeling domain is 51.1 ppb.
Additionally, as shown in Table 8, the
most recent 3-year design value for
Douglas County, Nebraska, containing
the North Omaha Station is 34 ppb.
Nebraska evaluated available
meteorological data to determine the
wind patterns near Ash Grove Cement
Company and Douglas County
Recycling Landfill. For the Ash Grove
Cement Company, Nebraska included a
wind rose for the Plattsmouth airport
that depicts the predominant wind
pattern in the area as being in a
Southeast-Northwest pattern which
would blow emissions away from the
Walter Scott Jr. facility in Iowa.65 For
the Douglas County Recycling Landfill,
Nebraska included a wind rose for the
Omaha/Eppley airport that depicts the
predominant wind pattern in the area as
being in a South-Southeast and NorthNorthwest wind pattern which would
keep emissions from Douglas County
Recycling Landfill in Nebraska.66
Nebraska also referenced the low design
values at the monitors located in Omaha
(as shown in Table 2) between the
Douglas County Recycling Landfill and
the Walter Scott Jr. facility in Iowa that
similarly support the claim that the
Douglas County Recycling Landfill is
not causing or contributing to violations
of the NAAQS in Iowa. Based on the
respective distances from Ash Grove
Cement Company and Douglas County
Recycling Landfill to the Nebraska
border, the localized nature of SO2, and
the general wind patterns in the area as
referenced by Nebraska, the EPA agrees
that it is unlikely these Nebraska
sources could on their own cause or
contribute to a violation in the
neighboring State of Iowa.
For the remaining three Nebraska
sources listed in Table 11, there are no
cross-state sources located within 50 km
of the Nebraska source meaning it is
unlikely there is an air quality problem
in the neighboring state to which the
Nebraska sources could contribute.
Additionally, based on the distance
from each Nebraska source to the border
along with the localized nature of SO2,
the EPA finds it unlikely that these
sources could on their own cause or
contribute to a violation in any other
state. As shown in Table 12, Exide
Technologies in Missouri is located 7
64 Nebraska limited its analysis to Nebraska
sources of SO2 emitting at least 100 tpy. We agree
with Nebraska’s choice to limit its analysis in this
way, because in the absence of special factors, for
example the presence of a nearby larger source, a
high concentration of small sources in an area, or
unusual physical factors, Nebraska sources emitting
less than 100 tpy can appropriately be presumed to
not be causing or contributing to SO2
concentrations above the NAAQS.
65 See page 24 of Nebraska’s SO Transport SIP
2
Submittal included in the docket for this action for
the wind rose referenced by Nebraska.
66 See page 32 of Nebraska’s SO Transport SIP
2
Submittal included in the docket for this action for
the wind rose referenced by Nebraska.
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km from the Nebraska border; however,
there are no Nebraska sources within 50
km which could contribute to a
potential air quality problem in
Missouri near the Exide facility.
In conclusion, for interstate transport
prong 1, we reviewed ambient SO2
monitoring data and SO2 emissions
information as well as available
modeling information for sources both
within Nebraska and in neighboring
states within 50 km of Nebraska’s
borders. Based on this analysis, we
propose to determine that Nebraska will
not significantly contribute to
nonattainment of the 2010 SO2 NAAQS
in any other state, per the requirements
of CAA section 110(a)(2)(D)(i)(I).
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3. The EPA’s Prong 2 Evaluation
In its prong 2 analysis, Nebraska
reviewed potential SO2 impacts on
designated maintenance areas. The EPA
interprets CAA section 110(a)(2)(D)(i)(I)
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, rather than
only former nonattainment, and thus
current maintenance, areas. Nebraska
also performed a prong 2 analysis based
on the EPA’s interpretation, noting that
monitors located near Nebraska in
neighboring states showed very low
levels of SO2 and emissions in Nebraska
and neighboring states have decreased,
indicating they should not be
considered to have maintenance issues
for this NAAQS.
The EPA has reviewed Nebraska’s
analysis and other available information
on SO2 air quality and emission trends
to evaluate the state’s conclusion that
Nebraska will not interfere with
maintenance of the 2010 SO2 NAAQS in
downwind states. This evaluation
builds on the analysis regarding
significant contribution to
nonattainment (prong 1), which
evaluated monitored ambient
concentrations of SO2 in Nebraska and
neighboring states, available modeling
results, the distances between crossstate SO2 sources, and other factors. The
EPA is proposing to find that SO2 levels
in neighboring states near the Nebraska
border do not indicate any inability to
maintain the SO2 NAAQS that could be
attributed in part to sources in
Nebraska.
As shown in Table 1, the statewide
SO2 emissions from Nebraska and
neighboring states have decreased
substantially over time, per our review
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of the EPA’s emissions trends data.67
From 2000 to 2019, total statewide SO2
emissions decreased by the following
proportions: Colorado (85% decrease),
Iowa (76% decrease), Kansas (83%
decrease), Missouri (72% decrease),
Nebraska (40% decrease), South Dakota
(88% decrease) and Wyoming (70%
decrease). This trend of decreasing SO2
emissions does not by itself demonstrate
that areas in Nebraska and neighboring
states will not have issues maintaining
the 2010 SO2 NAAQS. However, as a
piece of this weight of evidence analysis
for prong 2, it provides further
indication (when considered alongside
low monitor values in neighboring
states as depicted in Table 2) that such
maintenance issues are unlikely. This is
because the geographic scope of these
reductions and their large sizes strongly
suggest that they are not transient effects
from reversible causes, and thus these
reductions suggest that there is very low
likelihood that a strong upward trend in
emissions will occur that might cause
areas presently in attainment to violate
the NAAQS. These reductions have
been caused by regulatory requirements
in Nebraska and the downwind states
and by economic factors, such as low
natural gas prices and the increasing
supply of renewable energy, that are not
likely to be reversed.68
The EPA also evaluated federal
regulations which have helped to
reduce SO2 emissions from various
sources in Nebraska and neighboring
states. The EPA’s Acid Rain Program set
a permanent cap on the total amount of
SO2 that may be emitted by EGUs in the
contiguous United States.69 CSAPR
requires significant reductions in SO2
emissions from power plants in the
eastern half of the United States,
including Nebraska and neighboring
states.70 MATS requires reductions of
emissions of heavy metals which, as a
co-benefit, reduce emissions of SO2, and
establishes alternative numeric emission
standards, including SO2 (as an
alternate to hydrochloric acid).71 The
EPA’s Nonroad Diesel Rule will reduce
sulfur levels from about 3,000 parts per
million (ppm) to 15 ppm when fully
implemented.72 The EPA’s Heavy-Duty
Engine and Vehicle Standards and
67 Additional emissions trends data are available
at: https://www.epa.gov/air-emissions-inventories/
air-pollutant-emissions-trends-data.
68 Nebraska provided information on emission
reductions and control equipment for certain
sources in its SIP and the EPA summarized this
information in its prong 1 analysis.
69 See 40 CFR parts 72 through 78.
70 See 40 CFR part 97. See also 76 FR 48208.
71 See 40 CFR parts 60 and 63. See also 77 FR
9304.
72 See 40 CFR parts 9, 69, 80, 86, 89, 94, 1039,
1048, 1051, 1065, and 1068. See also 69 FR 38958.
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31657
Highway Diesel Fuel Sulfur Control
Requirements (Heavy-Duty Diesel Rule)
required refiners to start producing
diesel fuel for use in highway vehicles
with a sulfur content of no more than
15 ppm as of June 1, 2006.73 NSPS for
various source categories, including but
not limited to Industrial-CommercialInstitutional Steam Generating Units; 74
Sulfuric Acid Plants; 75 Stationary Gas
and Combustion Turbines; 76 Portland
Cement Manufacturing; 77 Electric
Utility Steam Generating Units
(Boilers); 78 and Onshore Natural Gas
Processing,79 establish standards which
reduce SO2 emissions.
In addition, the EPA’s Tier 3 Motor
Vehicle Emission and Fuel Standards
Rule 80 also reduce SO2 emissions by
establishing gasoline sulfur standards
that reduce SO2 emissions from certain
types of mobile sources. The EPA finds
that these federal measures have and
continue to lower SO2 emissions,
which, in turn, are expected to continue
to support the EPA’s proposed
conclusion that SO2 emissions from
Nebraska will not contribute
significantly to nonattainment or
interfere with maintenance of the 2010
1-hour SO2 NAAQS in another state.
As noted in Nebraska’s submission,
any future large sources of SO2
emissions will be addressed by
Nebraska’s SIP-approved PSD
program.81 Future minor sources of SO2
emissions will be addressed by
Nebraska’s minor new source review
permit program.82 The permitting
regulations contained within these
programs should help ensure that
ambient concentrations of SO2 in
neighboring states are not exceeded as a
result of new facility construction or
modification occurring in Nebraska.
In conclusion, for interstate transport
prong 2, we reviewed additional
information about SO2 air quality and
emission trends, federal regulations, and
Nebraska’s permitting regulations, as
well as the technical information
73 See 40 CFR parts 69, 80, and 86. See also 66
FR 5002.
74 See 40 CFR part 60, subpart Da and 40 CFR part
63. See also 77 FR 9304.
75 See 40 CFR part 60, subparts A, D, E, F, G and
H. See also 36 FR 24876.
76 See 40 CFR part 60, subparts GG and KKKK.
See also 71 FR 38482 and 44 FR 52792.
77 See 40 CFR parts 60 and 63. See also 75 FR
54970.
78 See 40 CFR part 60, subpart Da and 40 CFR part
63. See also 77 FR 9304.
79 See 40 CFR part 60, subpart LLL. See also 77
FR 49490.
80 See 40 CFR parts 79, 80, 85, 86, 600, 1036,
1037, 1039, 1042, 1048, 1054, 1065, and 1066. See
also 79 FR 23414.
81 See EPA’s final action of the PSD portions of
Nebraska’s SIP, at 83 FR 14179, April 2, 2018.
82 Id.
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considered for interstate transport prong
1. We find that the combination of low
ambient concentrations of SO2 in
Nebraska and neighboring states,
available modeling results, the distances
between cross-state SO2 sources, the
downward trend in SO2 emissions from
Nebraska and surrounding states, and
state measures that prevent new facility
construction or modification in
Nebraska from causing SO2 exceedances
in downwind states, indicates no
interference with maintenance of the
2010 SO2 NAAQS from Nebraska in
other states. Accordingly, we propose to
determine that Nebraska SO2 emission
sources will not interfere with
maintenance of the 2010 SO2 NAAQS in
any other state, per the requirements of
CAA section 110(a)(2)(D)(i)(I).
V. Requirements for Approval of a SIP
Revision
The State submissions have met the
public notice requirements for SIP
submissions in accordance with 40 CFR
51.102. The submissions also satisfied
the completeness criteria of 40 CFR part
51, appendix V. Kansas provided public
notice on its SIP revision from January
16, 2020, to February 17, 2020, and
received no comments. Nebraska
provided public notice on its SIP
revision from September 14, 2020, to
October 16, 2020, and received no
comments. In addition, the revision
meets the substantive SIP requirements
of the CAA, including section 110 and
implementing regulations.
VI. Proposed Action
The EPA is proposing to approve the
following submittals as meeting the
interstate transport requirements of
CAA section 110(a)(2)(D)(i)(I) for the
2010 SO2 NAAQS: Kansas’ April 7, 2020
submittal and Nebraska’s October 27,
2020 submittal. The EPA is proposing
this approval based on our review of the
information and analysis provided by
each state, as well as additional relevant
information, which indicates that instate air emissions will not contribute
significantly to nonattainment or
interfere with maintenance of the 2010
SO2 NAAQS in any other state. This
action is being taken under section 110
of the CAA.
VII. Statutory and Executive Order
Reviews
Under the Clean Air Act, the
Administrator is required to approve a
SIP submission that complies with the
provisions of the Act and applicable
federal regulations. 42 U.S.C. 7410(k);
40 CFR 52.02(a). Thus, in reviewing SIP
submissions, the EPA’s role is to
approve state choices, provided that
they meet the criteria of the CAA.
Accordingly, these proposed actions
merely approve state law as meeting
federal requirements and do not impose
additional requirements beyond those
imposed by state law. For that reason,
these proposed actions:
• Are not significant regulatory
actions subject to review by the Office
of Management and Budget under
Executive Order 12866 (58 FR 51735,
October 4, 1993);
• Do not impose an information
collection burden under the provisions
of the Paperwork Reduction Act (44
U.S.C. 3501 et seq.);
• Are 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.);
• Do 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);
• Do not have Federalism
implications as specified in Executive
Order 13132 (64 FR 43255, August 10,
1999);
• Are not economically significant
regulatory actions based on health or
safety risks subject to Executive Order
13045 (62 FR 19885, April 23, 1997);
• Are not significant regulatory
actions subject to Executive Order
13211 (66 FR 28355, May 22, 2001);
• Are not subject to requirements of
section 12(d) of the National
Technology Transfer and Advancement
Act of 1995 (15 U.S.C. 272 note) because
this action does not involve technical
standards; and
• Do not provide the EPA with the
discretionary authority to address, as
appropriate, disproportionate human
health or environmental effects, using
practicable and legally permissible
methods, under Executive Order 12898
(59 FR 7629, February 16, 1994).
In addition, these SIPs are 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 in 40 CFR Part 52
Environmental protection, Air
pollution control, Incorporation by
reference, Intergovernmental relations,
Nitrogen dioxide, Particulate matter,
Reporting and recordkeeping
requirements, Sulfur dioxide, Volatile
organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: June 8, 2021.
Edward H. Chu,
Acting Regional Administrator, Region 7.
For the reasons stated in the
preamble, the EPA proposes to amend
40 CFR part 52 as set forth below:
PART 52—APPROVAL AND
PROMULGATION OF
IMPLEMENTATION PLANS
1. The authority citation for part 52
continues to read as follows:
■
Authority: 42 U.S.C. 7401 et seq.
Subpart R—Kansas
2. In § 52.870, the table in paragraph
(e) is amended by adding the entry
‘‘(46)’’ in numerical order to read as
follows:
■
§ 52.870
*
Identification of plan.
*
*
(e) * * *
*
*
khammond on DSKJM1Z7X2PROD with PROPOSALS
EPA-APPROVED KANSAS NONREGULATORY PROVISIONS
Name of nonregulatory SIP provision
*
*
(46) Section 110(a)(2)(D)(i)(I)—significant contribution
to nonattainment (prong 1), and interfering with
maintenance of the NAAQs (prong 2) (Interstate
Transport) Infrastructure Requirements for the
2010 SO2 NAAQS.
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Applicable
geographic or
nonattainment
area
State
submittal
date
*
Statewide .............
*
4/7/2020
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EPA approval date
Explanation
*
*
*
[Date of publication of final rule in [EPA–R07–OAR–2021–0365; FRL–
the Federal Register], [Federal
10024–81–Region 7]. This action
addresses the following CAA eleRegister citation of the final rule].
ments: 110(a)(2)(D)(i)(I)—prongs
1 and 2.
Sfmt 4702
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Federal Register / Vol. 86, No. 113 / Tuesday, June 15, 2021 / Proposed Rules
Subpart CC—Nebraska
3. In § 52.1420, the table in paragraph
(e) is amended by adding the entry
■
‘‘(37)’’ in numerical order to read as
follows:
§ 52.1420
*
Identification of plan.
*
*
(e) * * *
*
*
EPA-APPROVED NEBRASKA NONREGULATORY PROVISIONS
Applicable geographic or nonattainment area
State
submittal
date
*
*
(37) Section 110(a)(2)(D)(i)(I)—significant contribution
to nonattainment (prong 1), and interfering with
maintenance of the NAAQs (prong 2) (Interstate
Transport) Infrastructure Requirements for the
2010 SO2 NAAQS.
*
Statewide .............
*
10/27/2020
[FR Doc. 2021–12501 Filed 6–14–21; 8:45 am]
searching for ‘‘FTR Case 2020–302–1.
Select the link ‘‘Comment Now’’ that
corresponds with ‘‘FTR Case 2020–302–
1.’’ Follow the instructions provided on
the screen. Please include your name,
company name (if any), and ‘‘FTR Case
2020–302–1’’ on your attached
document. If your comment cannot be
submitted using https://
www.regulations.gov, call or email the
points of contact in the FOR FURTHER
INFORMATION CONTACT section of this
document for alternate instructions.
Instructions: Please submit comments
only and cite FTR Case 2020–302–1, in
all correspondence related to this case.
Comments received generally will be
posted without change to https://
www.regulations.gov, including any
personal and/or business confidential
information provided. To confirm
receipt of your comment(s), please
check www.regulations.gov,
approximately two to three days after
submission to verify posting.
FOR FURTHER INFORMATION CONTACT: Mr.
Rodney (Rick) Miller, Program Analyst,
Office of Government-wide Policy, at
202–501–3822 or rodney.miller@gsa.gov
for clarification of content. For
information pertaining to status or
publication schedules, contact the
Regulatory Secretariat Division at 202–
501–4755 or GSARegSec@gsa.gov.
Please cite ‘‘FTR Case 2020–302–1.’’
SUPPLEMENTARY INFORMATION:
Name of nonregulatory SIP provision
BILLING CODE 6560–50–P
GENERAL SERVICES
ADMINISTRATION
41 CFR Parts 300–3, 302–2, 302–3,
302–12, 302–15, and 302–17
[FTR Case 2020–302–1; Docket No. 2020–
0019, Sequence 1]
RIN 3090–AK31
Federal Travel Regulation; Taxes on
Relocation Expenses, Withholding Tax
Allowance (WTA) and Relocation
Income Tax Allowance (RITA)
Eligibility
Office of Government-wide
Policy (OGP), General Services
Administration (GSA).
ACTION: Proposed rule.
AGENCY:
The General Services
Administration (GSA), in consultation
with the Secretary of the Treasury, is
proposing to amend the Federal Travel
Regulation (FTR) to authorize
Withholding Tax Allowance (WTA) and
Relocation Income Tax Allowance
(RITA) to all individuals who receive
relocation allowances paid by the
Federal Government. This amendment
is in accordance with legislative
changes to GSA’s statutory authority for
taxes on reimbursements for travel,
transportation, and relocation expenses
as enacted in the National Defense
Authorization Act for Fiscal Year 2020.
DATES: Interested parties should submit
written comments to the Regulatory
Secretariat at one of the addresses
shown below on or before August 16,
2021 to be considered in the formation
of the final rule.
ADDRESSES: Submit comments in
response to FTR Case 2020–302–1:
Regulations.gov: https://
www.regulations.gov. Submit comments
via the Federal eRulemaking portal by
khammond on DSKJM1Z7X2PROD with PROPOSALS
SUMMARY:
VerDate Sep<11>2014
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EPA approval date
*
*
*
[Date of publication of final rule in [EPA–R07–OAR–2021–0365; FRL–
the Federal Register], [Federal
10024–81–Region 7]. This action
Register citation of the final rule].
addresses the following CAA elements: 110(a)(2)(D)(i)(I)—prongs
1 and 2.
I. Background
Federal agencies authorize relocation
entitlements to those listed at FTR
§ 302–1.1 and those assigned under the
Government Employees Training Act
(GETA) (5 U.S.C. Chapter 41).
Public Law (Pub. L.) 115–97, known
as the ‘‘Tax Cuts and Jobs Act of 2017,’’
suspended qualified moving expense
deductions along with the exclusion for
employer reimbursements and
payments of moving expenses effective
January 1, 2018, for tax years 2018
through 2025, therefore making almost
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Fmt 4702
Explanation
Sfmt 4702
all relocation entitlements subject to
additional tax liability.
To assist with the additional tax
liability, agencies are authorized to pay
WTA and RITA to cover ‘‘substantially
all’’ of the increased tax liability
resulting from receipt of the relocation
expense reimbursements either paid
directly or indirectly. However, in the
version of 5 U.S.C. 5724b immediately
preceding the passage of Section 1114 of
the ‘‘National Defense Authorization
Act for Fiscal Year 2020’’ (Pub. L. 116–
92) (‘‘the Act’’), WTA and RITA were
available only to employees
‘‘transferred’’ in the interest of the
Government from one official station or
agency to another for permanent duty.
Previously, new appointees
(including political appointees), Senior
Executive Service (SES) employees
performing a ‘‘last move home’’,
employees returning from an overseas
assignment for the purpose of separating
from Government service, and those
assigned under GETA were not eligible
for WTA and RITA as such individuals
were not ‘‘transferred’’ in the interest of
the Government from one official station
or agency to another for permanent
duty. The suspension of qualified
moving expense deductions in Public
Law 115–97 substantially increased the
tax liability of these individuals, which
could not be reimbursed through WTA
or RITA.
However, Section 1114 of the Act
amended 5 U.S.C. 5724b to expand
eligibility for WTA and RITA beyond
‘‘transferred’’ employees to include all
individuals whose travel,
transportation, or relocation expenses
are reimbursed or furnished in kind
pursuant to subchapter 57 or chapter 41
of title 5, U.S.C. These individuals
include, among others, those not
previously eligible for WTA and RITA,
e.g., new appointees (including political
appointees), employees returning from
an overseas assignment for the purpose
of separation from Government service,
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]]>Agencies
[Federal Register Volume 86, Number 113 (Tuesday, June 15, 2021)]
[Proposed Rules]
[Pages 31645-31659]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-12501]
========================================================================
Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
========================================================================
Federal Register / Vol. 86, No. 113 / Tuesday, June 15, 2021 /
Proposed Rules
[[Page 31645]]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R07-OAR-2021-0365; FRL-10024-81-Region 7]
Interstate Transport Prongs 1 and 2 for the 2010 Sulfur Dioxide
(SO2) Standard for Kansas and Nebraska
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve State Implementation Plan (SIP) submissions from Kansas and
Nebraska addressing the Clean Air Act (CAA or Act) interstate transport
SIP requirements for the 2010 Sulfur Dioxide (SO2) National
Ambient Air Quality Standards (NAAQS). These submissions address the
requirement that each SIP contain adequate provisions prohibiting air
emissions that will have certain adverse air quality effects in other
states. The EPA is proposing to approve portions of these
infrastructure SIPs for the aforementioned states as containing
adequate provisions to ensure that air emissions in the states will not
significantly contribute to nonattainment or interfere with maintenance
of the 2010 SO2 NAAQS in any other state.
DATES: Comments must be received on or before July 15, 2021.
ADDRESSES: The EPA has established a docket for this action under
Docket ID No. EPA-R07-OAR-2021-0365. All documents in the docket are
listed on the https://www.regulations.gov website. Although listed in
the index, some information may not be publicly available, i.e.,
Confidential Business Information or other information whose disclosure
is restricted by statute. Certain other material, such as copyrighted
material, is not placed on the internet and will be publicly available
only in hard copy form. Publicly available docket materials are
available either electronically through www.regulations.gov or in hard
copy at the Atmospheric Programs Section, Air Quality Planning Branch,
Air and Radiation Division, U.S. Environmental Protection Agency,
Region 7, 11201 Renner Boulevard, Lenexa, Kansas 66219. The EPA
requests that if at all possible, you contact the person listed in the
FOR FURTHER INFORMATION CONTACT section to schedule your inspection.
The Regional Office's official hours of business are Monday through
Friday 8:30 a.m. to 4:30 p.m., excluding federal holidays.
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
[email protected].
SUPPLEMENTARY INFORMATION: Throughout this document ``we,'' ``us,'' and
``our'' refer to the EPA.
Table of Contents
I. Written Comments
II. Background
A. Infrastructure SIPs
B. 2010 1-Hour SO2 NAAQS Designations
III. Relevant Factors To Evaluate 2010 SO2 Interstate
Transport SIPs
IV. States' Submissions and the EPA's Analysis
A. Kansas
1. State's Analysis
2. The EPA's Prong 1 Evaluation
3. The EPA's Prong 2 Evaluation
B. Nebraska
1. State's Analysis
2. The EPA's Prong 1 Evaluation
3. The EPA's Prong 2 Evaluation
V. Requirements for Approval of a SIP Revision
VI. Proposed Action
VII. Statutory and Executive Order Reviews
I. Written Comments
Submit your comments, identified by Docket ID No. EPA-R07-OAR-2021-
0365 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 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. Background
A. Infrastructure SIPs
On June 2, 2010, the EPA established a new primary 1-hour
SO2 NAAQS of 75 parts per billion (ppb), based on a three-
year average of the annual 99th percentile of 1-hour daily maximum
concentrations.\1\ The CAA requires states to submit, within three
years after promulgation of a new or revised NAAQS, SIPs meeting the
applicable ``infrastructure'' elements of sections 110(a)(1) and (2).
One of these applicable infrastructure elements, CAA section
110(a)(2)(D)(i), requires SIPs to contain ``good neighbor'' provisions
to prohibit certain adverse air quality effects on neighboring states
due to interstate transport of pollution.
---------------------------------------------------------------------------
\1\ 75 FR 35520 (June 22, 2010).
---------------------------------------------------------------------------
Section 110(a)(2)(D)(i) includes four distinct components, commonly
referred to as ``prongs,'' that must be addressed in infrastructure SIP
submissions. The first two prongs, which are codified in section
110(a)(2)(D)(i)(I), require SIPs to contain adequate provisions that
prohibit any source or other type of emissions activity in one state
from contributing significantly to nonattainment of the NAAQS in
another state (prong 1) and from interfering with maintenance of the
NAAQS in another state (prong 2). The third and fourth prongs, which
are codified in section 110(a)(2)(D)(i)(II), require SIPs to contain
adequate provisions that prohibit emissions activity in one state from
interfering with measures required to prevent significant deterioration
of air quality in another state (prong 3) or from interfering with
measures to protect visibility in another state (prong 4).
[[Page 31646]]
In this action, the EPA is proposing to approve the prong 1 and
prong 2 portions of infrastructure SIP submissions submitted by Kansas
on April 7, 2020, and Nebraska on October 27, 2020, as demonstrating
that the SIP contains adequate provisions to ensure that air emissions
from sources in these states will not significantly contribute to
nonattainment or interfere with maintenance of the 2010 SO2
NAAQS in any other state or each other. All other applicable
infrastructure SIP requirements for these SIP submissions are addressed
in separate rulemakings.
B. 2010 1-Hour SO2 NAAQS Designations
In this action, the EPA has considered information from the 2010 1-
hour SO2 NAAQS designations process, as discussed in more
detail in Section IV of this document. For this reason, a brief summary
of the EPA's designations process for the 2010 1-hour SO2
NAAQS is included here.\2\ All technical support documents referenced
throughout this document are also included in the docket for this
action.
---------------------------------------------------------------------------
\2\ While designations may provide useful information for
purposes of analyzing transport, the EPA notes that designations
themselves are not dispositive of whether or not upwind emissions
are impacting areas in downwind states. The EPA has consistently
taken the position that CAA section 110(a)(2)(D) requires
elimination of significant contribution and interference with
maintenance in other states, and this analysis is not limited to
designated nonattainment areas. Nor must designations for
nonattainment areas have first occurred before states or the EPA can
act under section 110(a)(2)(D). See e.g., Clean Air Interstate Rule,
70 FR 25162, 25265 (May 12, 2005); Cross-State Air Pollution Rule,
76 FR 48208, 48211 (Aug. 8, 2011); Final Response to Petition from
New Jersey Regarding SO2 Emissions From the Portland
Generating Station, 76 FR 69052 (Nov. 7, 2011) (finding facility in
violation of the prohibitions of CAA section 110(a)(2)(D)(i)(I) with
respect to the 2010 1-hour SO2 NAAQS prior to issuance of
designations for that standard).
---------------------------------------------------------------------------
After the EPA establishes a new or revised NAAQS, the 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 the 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, the EPA has the authority to extend the deadline for
completing designations by up to one year.
The EPA Administrator signed the first round of designations
(``round 1'') \3\ 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). The EPA
Administrator signed Federal Register documents for round 2
designations \4\ on June 30, 2016 (81 FR 45039 (July 12, 2016)), and on
November 29, 2016 (81 FR 89870 (December 13, 2016)), round 3
designations \5\ on December 21, 2017 (83 FR 1098 (January 9, 2018)),
and round 4 designations \6\ on December 21, 2020 (86 FR 16055 (March
26, 2021)) and on April 8, 2021 (86 FR 19576 (April 14, 2021)).\7\
---------------------------------------------------------------------------
\3\ The term ``round'' in this instance refers to which ``round
of designations.''
\4\ 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 the EPA's website for
SO2 designations at https://www.epa.gov/sulfur-dioxide-designations.
\5\ 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 the EPA's website for
SO2 designations at https://www.epa.gov/sulfur-dioxide-designations.
\6\ EPA and state documents and public comments related to round
4 final designations are in the docket at regulations.gov with
Docket ID No. EPA-HQ-OAR-2020-0037 and at the EPA's website for
SO2 designations at https://www.epa.gov/sulfur-dioxide-designations.
\7\ The Round 4 2010 SO2 NAAQS designations action
was signed by then EPA Administrator, Andrew Wheeler, on December
21, 2020, pursuant to a court-ordered deadline of December 31, 2020.
For administrative purposes only, and in compliance with
requirements of the Office of the Federal Register, Acting
Administrator Jane Nishida re-signed the same action on March 10,
2021 for publication in the Federal Register.
---------------------------------------------------------------------------
At the time of this proposed action, there are no nonattainment
areas for the 2010 1-hour SO2 NAAQS in Kansas or Nebraska.
There are two areas designated as unclassifiable, one in Kansas and one
in Nebraska, the remaining areas in these states are designated as
attainment/unclassifiable.
III. Relevant Factors To Evaluate 2010 SO2 Interstate Transport SIPs
Although SO2 is emitted from a similar universe of point
and nonpoint sources, interstate transport of SO2 is unlike
the transport of fine particulate matter (PM2.5) or ozone,
in that SO2 is not a regional pollutant and does not
commonly contribute to widespread nonattainment over a large (and often
multi-state) area. The transport of SO2 is more analogous to
the transport of lead (Pb) because its physical properties result in
localized pollutant impacts very near the emissions source. However,
ambient concentrations of SO2 do not decrease as quickly
with distance from the source as Pb because of the physical properties
and typical release heights of SO2. Emissions of
SO2 travel farther and have wider ranging impacts than
emissions of Pb but do not travel far enough to be treated in a manner
similar to ozone or PM2.5. The approaches that the EPA has
adopted for ozone or PM2.5 transport are too regionally
focused and the approach for Pb transport is too tightly circumscribed
to the source. SO2 transport is therefore a unique case and
requires a different approach.
Given the physical properties of SO2, the EPA selected
the ``urban scale''--a spatial scale with dimensions from 4 to 50
kilometers (km) from point sources--given the usefulness of that range
in assessing trends in both area-wide air quality and the effectiveness
of large-scale pollution control strategies at such point sources.\8\
The EPA's selection of this transport distance for SO2 is
based upon 40 CFR part 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
the 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. As such, the EPA utilized an assessment up to 50 km
from point sources in order to assess trends in area-wide air quality
that might impact downwind states.
---------------------------------------------------------------------------
\8\ For the definition of spatial scales for SO2,
please see 40 CFR part 58, appendix D, section 4.4 (``Sulfur Dioxide
(SO2) Design Criteria''). For further discussion on how
the EPA is applying these definitions with respect to interstate
transport of SO2, see the EPA's proposal on Connecticut's
SO2 transport SIP. 82 FR 21351, 21352, 21354 (May 8,
2017).
---------------------------------------------------------------------------
As discussed in Section IV of this proposed action, the EPA first
reviewed each state'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. The EPA
then conducted a weight of evidence analysis, including review of each
state's submission and other available information, including air
quality, emission sources and emission trends within the state and in
bordering states to which it could potentially contribute or
interfere.\9\
---------------------------------------------------------------------------
\9\ 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 any of the subject state's air quality
status. Any such future actions, such as area designations under any
NAAQS, will be based on their own administrative records and the
EPA's analyses of information that becomes available at those times.
Future available information may include, and is not limited to,
monitoring data and modeling analyses conducted pursuant to the
EPA's SO2 Data Requirements Rule (80 FR 51052, August 21,
2015) and information submitted to the EPA by states, air agencies,
and third party stakeholders such as citizen groups and industry
representatives.
---------------------------------------------------------------------------
[[Page 31647]]
IV. States' Submissions and EPA's Analysis
In this section, we provide an overview of each state's 2010
SO2 transport analysis, as well as the EPA's evaluation of
prongs 1 and 2 for each state. Table 1 shows emission trends for the
states addressed in this document along with their neighboring
states.\10\ Table 2 shows ambient air monitoring data for monitors
located within 50 km of the borders of either Kansas or Nebraska. Table
3 shows emissions trends for sources in Kansas and Nebraska emitting
over 100 tons per year (tpy) located within 50 km of the border with
another state. Tables 1, 2 and 3 will be referenced as part of the
EPA's analysis for each state.
---------------------------------------------------------------------------
\10\ This emissions trends information was derived from the
EPA's web page https://www.epa.gov/air-emissions-inventories/air-pollutant-emissions-trends-data.
Table 1--Statewide SO2 Emission Trends
[In tons per year]
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2 reduction,
State 2000 2005 2010 2015 2019 2000-2019 (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Colorado................................................ 115,122 80,468 60,459 28,860 17,045 85
Iowa.................................................... 265,005 222,419 142,738 84,932 64,294 76
Kansas.................................................. 148,416 199,006 80,267 36,828 24,855 83
Missouri................................................ 401,287 425,167 321,059 158,998 110,888 72
Nebraska................................................ 86,894 121,785 77,898 63,237 51,886 40
Oklahoma................................................ 145,862 169,464 136,348 99,095 45,996 68
South Dakota............................................ 41,120 28,579 16,202 11,975 5,093 88
Wyoming................................................. 141,439 122,453 91,022 53,335 42,191 70
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 2--SO2 Monitor Values Within 50 km of the Nebraska or Kansas Border
----------------------------------------------------------------------------------------------------------------
Distance to Kansas Distance to Nebraska
border (km) * (nearest border (km) * (nearest 2017-2019
State/area Site ID state listed for state listed for design value
monitors in Kansas) monitors in Nebraska) (ppb) \11\
----------------------------------------------------------------------------------------------------------------
South Dakota/Sioux City..... 461270001 305..................... 10...................... 3
Kansas/Wyandotte County..... 202090021 2 (Missouri)............ 114..................... 6
Nebraska/Omaha.............. 310550053 147..................... 0.5 (Iowa).............. 41
Nebraska/Omaha.............. 310550019 138..................... 4.5 (Iowa).............. 24
Nebraska/Omaha.............. 310550057 146..................... 1.5 (Iowa).............. 34
Missouri/Jackson County..... 290950034 3....................... 118..................... 10
Oklahoma/Ponca City......... 400710604 33...................... 367..................... 28
Oklahoma/Enid............... 400470555 54...................... 387..................... 48
----------------------------------------------------------------------------------------------------------------
* All distances throughout this document are approximations.
Table 3--SO2 Emission Trends for Kansas and Nebraska Sources Within 50 km of a State Border
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2 emissions (tons) % change
State/county Facility name EIS Distance to nearest ----------------------------------------------------------------
facility ID state (km) 2011 2014 2017 2019 2011-2019
--------------------------------------------------------------------------------------------------------------------------------------------------------
Kansas/Johnson................. AGC Flat Glass.... 4538011 18, Missouri......... 243.83 154.51 157.42 133.06 -45.43
Kansas/Linn.................... Evergy--La Cygne.. 5367811 3, Missouri.......... 17,872.15 12,639.08 619.07 719.98 -95.97
Kansas/Douglas................. Evergy--Lawrence.. 4827111 44, Missouri......... 2,792.76 1,845.46 295.11 471.72 -83.11
Kansas/Wyandotte............... Kansas City BPU-- 4633811 0.5, Missouri........ 5,989.47 5,332.61 904.01 1,203.00 -79.91
Nearman.
Nebraska/Otoe.................. Nebraska City 7303711 0.3, Iowa............ 17,334.65 16,134.40 15,950.20 10,386.51 -40.08
Station.
Nebraska/Douglas............... North Omaha 6732411 0.3, Iowa............ 14,069.34 11,244.90 7,896.85 5,792.82 -58.83
Station.
Nebraska/Cass.................. Ash Grove Cement 7287311 24, Iowa............. 1,067.12 1,250.77 694.12 681.44 -36.14
Company.
Nebraska/Dodge................. Lon D Wright Power 7766111 33, Iowa............. 1,399.76 2,231.52 926.23 985.08 -29.63
Plant.
Nebraska/Kimball............... Clean Harbors 7768011 17, Colorado......... 0.62 222.81 221.36 205.93 \12\
Environmental 33114.1
Services.
Nebraska/Scotts Bluff.......... Western Sugar 7767911 35, Wyoming.......... 151.66 149.08 176.80 144.71 -4.58
Cooperative.
Nebraska/Douglas............... Douglas County 7699311 25, Iowa............. 111.98 102.53 131.04 164.59 46.98
Recycling
Landfill.
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 31648]]
A. Kansas
---------------------------------------------------------------------------
\11\ Data retrieved from the EPA's https://www.epa.gov/air-trends/air-quality-design-values#report.
---------------------------------------------------------------------------
1. State's Analysis
---------------------------------------------------------------------------
\12\ The EPA notes that emissions for Clean Harbors
Environmental Services decreased by 7.5% from 2014 to 2019.
---------------------------------------------------------------------------
In its SIP submittal, Kansas conducted a weight of evidence
analysis to examine whether SO2 emissions from Kansas
adversely affect attainment or maintenance of the 2010 SO2
NAAQS in downwind states.\13\ Kansas evaluated potential air quality
impacts on areas outside the state through an assessment of whether
SO2 emissions from sources located within 50 km of Kansas'
borders may have associated interstate transport impacts. The State's
analysis included SO2 emissions information in the state,
with specific focus on sources and counties located within 50 km of
Kansas' borders. Of the 11 facilities in Kansas with SO2
emissions greater than 100 tpy, only four facilities are located within
50 km of Kansas' borders: AGC Flat Glass (18 km from Missouri),
Evergy--La Cygne (3 km from Missouri), Evergy--Lawrence (44 km from
Missouri), and Kansas City BPU--Nearman (0.6 km from Missouri). Kansas
provided an in-depth analysis for these four facilities by assessing
current permitted emissions rates and existing control technologies.
Kansas also evaluated an additional six facilities with SO2
emissions greater than 10 tpy but less than 100 tpy, located within 50
km of Kansas' borders. Kansas also reviewed meteorological conditions
representative of SO2 sources near the state's border, and
the distances from identified SO2 sources in Kansas to the
nearest area that is not attaining the NAAQS or may have trouble
maintaining the NAAQS in another state. Kansas also reviewed statewide
emissions and ambient air monitoring trends. Finally, Kansas reviewed
mobile source emissions data from highway and off-highway vehicles and
population data in all of the Kansas counties which border other
states. Based on this weight of evidence analysis, Kansas concluded
that emissions from sources within the state will not contribute to
nonattainment or interfere with maintenance of the 2010 SO2
NAAQS in neighboring states.
---------------------------------------------------------------------------
\13\ See Kansas' SO2 interstate transport SIP as
submitted in January 2020 in the docket for this action.
---------------------------------------------------------------------------
2. The EPA's Prong 1 Evaluation
The EPA proposes to find that Kansas' SIP meets the interstate
transport requirements of CAA section 110(a)(2)(D)(i)(I), prong 1 for
the 2010 SO2 NAAQS, as discussed below. To support our
proposal, we completed a weight of evidence analysis which considers an
evaluation of ambient air quality data and of available information for
certain emission sources near the Kansas border, as well as available
modeling results for sources in Kansas or neighboring states within 50
km of Kansas' borders. Based on that analysis, we propose to find that
Kansas will not significantly contribute to nonattainment of the 2010
SO2 NAAQS in any other state.
To assess ambient air quality, the EPA reviewed monitoring data in
Kansas and neighboring states to see whether there were any monitoring
sites, particularly near the Kansas border, with elevated
SO2 concentrations that might warrant further investigation
with respect to interstate transport of SO2 from emission
sources in Kansas to a neighboring state near any given monitor. We
reviewed 2017-2019 SO2 design value concentrations at
monitors with data sufficient to produce valid 1-hour SO2
design values for Kansas and neighboring states.\14\ In Table 2, we
have included all monitors in each neighboring state and in Kansas
within 50 km of the Kansas border. As shown, there are no violating
design values in Kansas or neighboring states within 50 km of the state
border. In Kansas' analysis, the state reviewed its potential impact on
the existing 2010 SO2 nonattainment area in Jackson County,
Missouri, which is the only designated nonattainment area within 50 km
of Kansas' borders.
---------------------------------------------------------------------------
\14\ Id.
---------------------------------------------------------------------------
The data presented in Table 2 shows that Kansas has one
SO2 monitor within 50 km of its borders, in Wyandotte
County. The 2017-2019 design value for this monitor is 6 ppb, or 8% of
the 75 ppb level of the NAAQS. Two monitors in neighboring states are
located within 50 km of the Kansas border, and these monitors recorded
SO2 design values ranging between 13% and 37% of the level
of the 2010 SO2 NAAQS. Thus, these air quality data do not,
by themselves, indicate any particular location that would warrant
further investigation with respect to SO2 emission sources
that might significantly contribute to nonattainment in the bordering
states. However, because the monitoring network is not necessarily
designed \15\ to find all locations of high SO2
concentrations, this observation indicates an absence of evidence of
impact at these locations but is not sufficient evidence by itself of
an absence of impact at all locations in the neighboring states. We
have therefore considered additional evidence to support our conclusion
that Kansas will not significantly contribute to nonattainment of the
2010 SO2 NAAQS in any other state.
---------------------------------------------------------------------------
\15\ State monitoring networks must meet the minimum monitoring
requirements contained in appendix D to 40 CFR part 58.
Specifically, section 4.4 of appendix D outlines the minimum
monitoring requirements for SO2 monitoring based on
population weighted emissions. Monitors sited to meet the minimum
monitoring requirements are sited for a number of reasons (e.g.
measuring a source's maximum contribution, measuring background
concentrations, monitoring population exposure, etc.) and may not
necessarily capture maximum impacts from specific sources. However,
data from these monitors may still provide useful evidence in the
context of interstate transport.
---------------------------------------------------------------------------
In the next step of our weight of evidence analysis, the EPA
evaluated available modeling results for sources in Kansas and in the
adjacent states that are within 50 km of the Kansas border. The purpose
for evaluating modeling for sources in Kansas within 50 km of the
Kansas border is to determine whether these sources are, either on
their own or in conjunction with other sources near the border,
impacting a violation of the 2010 1-hour SO2 NAAQS in
another state. The purpose of evaluating modeling results in adjacent
states within 50 km of the Kansas border is to ascertain whether there
are any modeled violations in neighboring states to which sources in
Kansas could potentially be contributing.
Table 4 provides a summary of the modeling results for two sources
in Kansas which have available modeling information and are located
within 50 km of another state: Evergy--La Cygne Generating Station (La
Cygne) and the Board of Public Utilities Nearman Creek Station
(Nearman). The modeling analyses resulted in no modeled violations of
the 2010 1-hour SO2 NAAQS within the modeling domain for
each facility. The emission trends for these facilities are also
provided in Table 3, and the EPA has verified that the most recent
annual emissions are below the annual emissions from the years modeled
at each modeled source. The modeling submitted by Kansas in September
2015 for La Cygne was based on allowable emissions and resulted in a
maximum impact of 52.6 ppb or 70% of the level of the NAAQS.\16\ Kansas
[[Page 31649]]
indicated in its SIP that Evergy La Cygne is comprised of two coal-
fired boilers, one of which is equipped with a wet lime scrubber with a
95% efficiency for controlling SO2 emissions.\17\ The
emissions limits associated with these controls were modeled by Kansas
and resulted in a concentration gradient within the domain that does
not lead the EPA to believe that there would be substantial impacts
beyond the modeling domain. There are no SO2 sources in
Missouri within 50 km of La Cygne around which the EPA would expect
elevated concentrations to which La Cygne could contribute.
---------------------------------------------------------------------------
\16\ See the EPA's Technical Support Document for its Intended
Round 2 Designations for the 2010 SO2 NAAQS for Kansas
available at: https://www.epa.gov/sites/production/files/2016-03/documents/ks-epa-tsd-r2.pdf and the EPA's Technical Support Document
for its Final Round 2 Designations for the 2010 SO2 NAAQS
for Kansas available at: https://www.epa.gov/sites/production/files/2016-07/documents/r7_ks_final_designation_tsd_06302016.pdf.
\17\ Pursuant to La Cygne's operating permit No. O-11952 issued
on May 14, 2018, units 1 and 2 are subject to an emissions limit of
0.10 pounds per Million British Thermal Units (lb/MMBtu) on a 30-day
rolling average.
---------------------------------------------------------------------------
For Nearman, the EPA evaluated two sets of available modeling
results. The first, depicted in Table 4, includes modeling submitted by
the State of Kansas.\18\ That modeling was based on actual emissions
from 2012-2014 and resulted in a maximum impact of 49.2 ppb, or 66% of
the level of the NAAQS. The second set of modeling results was
submitted by the State of Missouri and was the basis of the clean data
determination for the Jackson County, Missouri 1-hour SO2
nonattainment area. That modeling, depicted in Table 5 as associated
with nearby sources in Missouri, included actual emissions for Nearman
from 2016-2018.\19\ This modeling demonstrates that there are no
violations in the designated Jackson County nonattainment area to which
Kansas sources could contribute. Kansas explicitly reviewed the Jackson
County, Missouri, 2010 1-hour SO2 nonattainment area, as
part of its analysis and concluded that Kansas sources do not
contribute to violations in the area as it is no longer experiencing
violations of the NAAQS. Further, the EPA previously determined that
the Jackson County, Missouri nonattainment area has attained the
standard and thereby the EPA agrees with Kansas' conclusion that there
are no violations in this area to which Kansas sources could
contribute.\20\ Additionally, as shown in Table 2, the monitor in the
Jackson County, Missouri nonattainment area is currently monitoring
concentrations well below the level of the standard. Kansas indicated
in its SIP that BPU-Nearman is comprised of two units, one of which is
equipped with a circulating dry scrubber for SO2
control.\21\ BPU-Nearman is also subject to the acid gas emissions
limit of the Mercury and Air Toxics Standard (MATS) and opts to meet
this limit by complying with the SO2 emissions limits
spelled out in 40 CFR part 63, subpart UUUUU. Based on the downward
trend in emissions since the modeled time period, specifically
emissions from BPU-Nearman have decreased by approximately 80% from
2011 to 2019, the EPA finds the available modeling to be a conservative
estimate of current actual air quality and an indicator that the
Jackson County, Missouri area is not likely to experience issues
maintaining the standard in the future. Additionally, it is unlikely
that the emissions from these facilities could increase in the future
to such a degree as to significantly contribute to nonattainment in any
other state.
---------------------------------------------------------------------------
\18\ See the EPA's Technical Support Document for its Intended
Round 2 Designations for the 2010 SO2 NAAQS for Kansas
available at: https://www.epa.gov/sites/production/files/2016-03/documents/ks-epa-tsd-r2.pdf and the EPA's Technical Support Document
for its Final Round 2 Designations for the 2010 SO2 NAAQS
for Kansas available at: https://www.epa.gov/sites/production/files/2016-07/documents/r7_ks_final_designation_tsd_06302016.pdf.
\19\ For more details on the modeling demonstration for Nearman
and the nearby sources (i.e. sources in nearby Missouri) included in
the modeling, see Determination of Attainment for the Jackson
County, Missouri 1-Hour SO2 NAAQS and Redesignation of
the Wyandotte County, Kansas Unclassifiable Area to Attainment/
Unclassifiable, 85 FR 41193, July 9, 2020.
\20\ See Id.
\21\ Pursuant to Nearman's operating permit No. O-14125, Unit
001 is subject to an annual SO2 emission limit of 3 lb/
MMBtu [K.A.R. 28-19-31(c) and 40 CFR 60.45(g)(2)]; 0.8 lb/MMBtu
derived from liquid fossil fuel [NSPS Subpart D40 CFR 60.43(a)(2)];
1.2 lb/MMBtu derived from solid fossil fuel [NSPS Subpart D40 CFR
60.43(a)(1)].
Table 4--Kansas Sources With Modeling Data Located Within 50 km of Another State
----------------------------------------------------------------------------------------------------------------
Modeled 99th
Distance from percentile 1-
2020 source to Other facilities hour SO2 maximum Model grid
Kansas source County emissions Kansas border included in concentration extends into
(tons) * (km) modeling (ppb) another state?
----------------------------------------------------------------------------------------------------------------
La Cygne...... Linn.......... 725 2.8 None............ 52.60 (based on No.
allowable
emissions).
Nearman....... Wyandotte..... 1,211 0.77 Numerous 49.24 (based on Yes (into
facilities 2012-2014 Jackson and
located in actual Platte County,
Jackson County, emissions for Missouri).
Missouri. all sources).
----------------------------------------------------------------------------------------------------------------
* Emissions data throughout this document were obtained using the EPA's Emissions Inventory System (EIS)
Gateway.
Table 5 provides a summary of the available modeling results for
sources with annual emissions of greater than 100 tons per year based
on the latest available emissions inventory in neighboring states which
are located within 50 km of Kansas: Evergy Hawthorn Generating Station
(Hawthorn), Audubon Materials (Audubon), and Empire Asbury in Missouri,
and Continental Carbon Black Production Facility in Ponca City,
Oklahoma. As stated above, we consider the air quality near these
sources in our analysis because, as a result of the localized nature of
SO2 as a pollutant, it is near these sources that sources in
Kansas are more likely to contribute to a violation of the standard.
For Hawthorn and Audubon, the EPA similarly evaluated the modeling
results of the clean data determination modeling for the Jackson
County, Missouri 1-hour SO2 nonattainment area, in which
actual emissions for Hawthorn and Audubon were explicitly included.
This modeling demonstrates that there are no violations in the
designated Jackson County nonattainment area to which Kansas sources
could contribute.\22\
---------------------------------------------------------------------------
\22\ See Determination of Attainment for the Jackson County,
Missouri 1-Hour SO2 NAAQS and Redesignation of the
Wyandotte County, Kansas Unclassifiable Area to Attainment/
Unclassifiable, 85 FR 41193, July 9, 2020.
---------------------------------------------------------------------------
The modeling submitted by Missouri for the Empire Asbury facility
was based on actual emissions and resulted in a maximum impact of 39
ppb, or 52% of the level of the NAAQS.\23\ The Empire Asbury facility,
located 2.5 km from the Kansas border, reported zero emissions in 2020
and officially retired in March
[[Page 31650]]
2020.\24\ Additionally, there are no Kansas sources located within 50
km of the Empire Asbury facility. The modeling submitted by Oklahoma
for the Continental Carbon facility in Kay, Oklahoma was based on
actual emissions and resulted in a maximum impact of 65.1 ppb, or 87%
of the level of the NAAQS.\25\ However, the emissions for this facility
have decreased from 5,893 tons in 2014 (the highest year in the modeled
period) to 2,995 tons in 2019. Additionally, the Continental Carbon
facility is located 37 km from the Kansas border and there are no
sources in Kansas within 50 km of the Continental Carbon facility. The
most recent available annual emissions for each source are also
provided in Table 5, and the EPA has verified that the most recent
annual emissions are below the annual emissions from the years modeled
at each modeled source. For these reasons, the EPA finds there are no
areas with modeled violations within 50 km of the Kansas border to
which Kansas sources could be contributing.
---------------------------------------------------------------------------
\23\ See the EPA's Technical Support Document for its Intended
Round 3 Designations for the 2010 SO2 NAAQS for Missouri
available at: https://www.epa.gov/sites/production/files/2017-08/documents/22_mo_so2_rd3-final.pdf and the EPA's Technical Support
Document for its Final Round 3 Designations for the 2010
SO2 NAAQS for Missouri available at: https://www.epa.gov/sites/production/files/2017-12/documents/22-mo-so2-rd3-final.pdf.
\24\ In a letter dated December 3, 2019, from Liberty Utilities
to the State of Missouri, Liberty Utilities requested that all air
permits for the Empire Asbury facility become void on the permanent
retirement date of March 1, 2020. This letter is included in the
docket for this action.
\25\ See the EPA's Technical Support Document for its Intended
Round 3 Designations for the 2010 SO2 NAAQS for Oklahoma
available at: https://www.epa.gov/sites/production/files/2017-12/documents/33-ok-so2-rd3-final.pdf and the EPA's Technical Support
Document for its Final Round 3 Designations for the 2010
SO2 NAAQS for Oklahoma available at: https://www.epa.gov/sites/production/files/2017-12/documents/33-ok-so2-rd3-final.pdf.
Table 5--Other States' Sources With Modeling Data Located Within 50 km of Kansas
--------------------------------------------------------------------------------------------------------------------------------------------------------
Distance from Modeled 99th
2019 source to Other facilities percentile 1-hour Model grid extends
Source County emissions Kansas border included in SO2 maximum into another state?
(tons) (km) modeling concentration (ppb)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Evergy Hawthorn................... Jackson, Missouri.... [caret] 929 9.7 Nearman (Wyandotte 43.47 (based on 2016- No.
County, Kansas); 2018 actual
other sources <100 emissions for all
tons per year. sources).
Audubon Materials, LLC Sugar Creek Jackson, Missouri.... 229 15 Nearman (Wyandotte 43.47 (based on 2016- No.
Plant. County, Kansas); 2018 actual
other sources <100 emissions for all
tons per year of sources).
SO2.
Empire Asbury..................... Jasper/Barton [caret] 0 2.5 Other Missouri 39.0 (based on 2012- Yes (into Crawford
Counties, Missouri. sources <100 tons 2014 actual and Cherokee
per year of SO2. emissions for all Counties in
sources). Kansas).
Continental Carbon Black Kay, Oklahoma........ 2,995 37 Oklahoma Gas & 65.1 (based on 2012- No.
Production Facility--Ponca City Electric, Sooner 2014 actual
Plant. Generating Station emissions for all
(Noble County, sources).
Oklahoma), Phillips
66 Company--Ponca
City Refinery (Kay
County, Oklahoma),
2 other Kay County,
Oklahoma sources
<100 tons per year
of SO2.
--------------------------------------------------------------------------------------------------------------------------------------------------------
[caret] Based on 2020 emissions.
The EPA proposes to find that the modeling results summarized in
Tables 4 and 5, which provide evidence that air quality near certain
larger sources in other states is attaining the NAAQS, when weighed
along with the other factors in this document, support the EPA's
proposed conclusion that sources in Kansas will not significantly
contribute to nonattainment of the 2010 1-hour SO2 NAAQS in
any other state.
The next step in our weight of evidence analysis is to assess
certain other sources near the border for which we do not have
available modeling or monitoring data. As noted in Section III of this
document, the EPA finds that it is appropriate to examine the impacts
of emissions from stationary sources in Kansas in distances ranging
from 0 km to 50 km from the facility, based on the ``urban scale''
definition contained in appendix D to 40 CFR part 58, section 4.4.
Kansas assessed point sources up to 50 km from state borders to
evaluate trends and SO2 concentrations in area-wide air
quality. The list of sources emitting 100 tpy \26\ or more of
SO2 within 50 km from state borders without available
modeling data, is shown in Table 6.
---------------------------------------------------------------------------
\26\ Kansas limited its analysis to Kansas sources of
SO2 emitting at least 100 tpy. We agree with Kansas'
choice to limit its analysis in this way, because in the absence of
special factors, for example the presence of a nearby larger source,
a high concentration of smaller sources in an area, or unusual
physical factors, Kansas sources emitting less than 100 tpy can
appropriately be presumed to not be causing or contributing to
SO2 concentrations above the NAAQS.
Table 6--Kansas SO2 Sources With No Available Modeling Data Near Neighboring States
----------------------------------------------------------------------------------------------------------------
Neighboring
Distance to state source
2019 SO2 Distance to nearest 2019
Kansas source Facility ID emissions Kansas border neighboring emissions
(tons) (km) state SO2 source (tons) [caret]
(km)
----------------------------------------------------------------------------------------------------------------
AGC Flat Glass................ 4538011 133.1 19 50 (Evergy [caret] 929
Hawthorn).
Evergy Lawrence............... 4827111 [caret] 225.5 44 55 (Evergy [caret] 812
Iatan).
----------------------------------------------------------------------------------------------------------------
[caret] Based on 2020 emissions.
Table 6 shows the distance from the sources listed therein to the
nearest out-of-state source emitting above 100 tpy of SO2,
because elevated levels of SO2, to which SO2
emitted in Kansas may have a downwind impact, are most likely to be
found near such sources. As shown in Table 6, the distance between the
sources in Kansas and the nearest
[[Page 31651]]
sources emitting over 100 tpy in Missouri is greater than or equal to
50 km. Additionally, Kansas evaluated the current operations and
control equipment at the AGC Flat Glass and Evergy Lawrence facilities.
In its SIP, Kansas indicated that the AGC Flat Glass facility operates
a glass melting furnace which is equipped with dry sorbent injection
for control of SO2.\27\ The Evergy Lawrence facility is
comprised of two units which are both equipped with high-efficiency
scrubbers for SO2 control.\28\ Kansas evaluated available
meteorological data to determine the wind patterns near AGC Flat Glass
and Evergy Lawrence. Kansas included wind roses for the Olathe Johnson
County airport that depict the predominant wind pattern in the area as
being from the South-Southwest blowing emissions from AGC Flat Glass
away from Missouri.\29\ Kansas included wind roses for the Lawrence
Municipal airport that depict the predominant wind pattern in the area
as being from the South-Southeast blowing emissions from Evergy
Lawrence away from the Jackson County nonattainment area.\30\
---------------------------------------------------------------------------
\27\ Pursuant to AGC's operating permit No. O-10871, unit EU-001
is subject to an SO2 emission limit of 2.2 lb of
SO2 per ton of glass produced on a 30-day rolling
average, and 262.8 tons of SO2 emissions per rolling
consecutive 12-month period.
\28\ Pursuant to Evergy Lawrence's operating permit No. O-11856
issued on February 14, 2018, units 4 and 5 are subject to an
emissions limit of 0.15 lb/MMBtu on a 30-day rolling average.
\29\ See Chapter 3 of Kansas' SO2 Transport SIP
Submittal included in the docket for this action for the wind rose
graphics referenced by Kansas.
\30\ See id.
---------------------------------------------------------------------------
Given the large distance between the cross-state sources, the
localized nature of SO2, and the wind rose analysis provided
by Kansas, the EPA agrees it is unlikely that emissions from AGC Flat
Glass or Evergy Lawrence in Kansas could interact with emissions from
Evergy Hawthorn or Evergy Iatan in Missouri in such a way as to cause a
violation of the NAAQS in Missouri. Additionally, based on the distance
from the Kansas sources to the border and the overall wind patterns in
the area, the EPA finds it unlikely that the sources in Kansas could on
their own cause a violation in Missouri.
The EPA also reviewed the location of sources for which modeling
information was not available in neighboring states emitting more than
100 tpy of SO2 and located within 50 km of the Kansas
border, as shown in Table 7. This is because elevated levels of
SO2, to which SO2 emitted in Kansas may have a
downwind impact, are most likely to be found near such sources.
Table 7--Neighboring State SO2 Sources With No Available Modeling Data Near Kansas *
----------------------------------------------------------------------------------------------------------------
Distance to
2019 SO2 Distance to nearest Kansas Kansas source
Source Facility ID emissions Kansas border SO2 source (km) 2020 emissions
(tons) (km) (tons)
----------------------------------------------------------------------------------------------------------------
Evergy Iatan Generating 6795111 [caret] 811.6 0.7 39 (Kansas City 1,211
Station (Missouri). BPU-Nearman).
Exide Technologies Canon 331492 158.5 7.1 106 (Kansas City 1,211
Hollow (Missouri). BPU-Nearman).
----------------------------------------------------------------------------------------------------------------
* We have not included sources that are duplicative of those in Table 6.
[caret] Based on 2020 emissions.
As shown in Table 7, the shortest distance between any pair of
these sources is 39 km (between Evergy Iatan in Missouri and Nearman in
Kansas). The available modeling data for the Nearman facility,
referenced in Tables 4 and 5, indicates that Nearman does not
significantly contribute to violations in nearby areas in Missouri as
there are no modeled violations in Missouri. Kansas evaluated available
meteorological data to determine the wind patterns near Nearman. Kansas
included wind roses for the Kansas City downtown airport that depict
the predominant wind pattern in the area around Nearman as being from
the South-Southwest blowing emissions from Nearman away from the
Jackson County nonattainment area.\31\ Additionally, based on the
distance between cross-state sources as well as the overall wind
patterns in the area as referenced by Kansas, the EPA agrees that it is
unlikely that emissions from Nearman could interact with emissions from
Every Iatan or Exide Technologies in such a way as to cause a violation
in Missouri.
---------------------------------------------------------------------------
\31\ See Id.
---------------------------------------------------------------------------
Kansas also evaluated two sources located within 50 km of its
borders that emitted above 80 tpy but below 100 tpy. The CRNF-
Coffeyville and CRRM-Refinery facilities are each located 5 km from the
Kansas border with Oklahoma. CRNF-Coffeyville emitted 83 tons of
SO2 in 2018. CRRM-Refinery emitted 93 tons of SO2
in 2018. There are no sources in Oklahoma within 50 km of these sources
such that their emissions could interact to impact a violation of the
NAAQS. Kansas also included wind roses for the Coffeyville Municipal
airport that depict the predominant wind pattern in the area as being
from the South blowing emissions from the Kansas sources away from
Oklahoma and further into Kansas.\32\ Given the localized nature of
SO2 and the overall wind pattern in the area as referenced
by Kansas, the EPA agrees it is unlikely that the CRNF-Coffeyville and
CRRM-Refinery facilities could on their own cause or contribute to a
violation in the nearby State of Oklahoma.
---------------------------------------------------------------------------
\32\ See Id.
---------------------------------------------------------------------------
This information together with the localized range of potential 1-
hour SO2 impacts indicates that there are no additional
locations in neighboring states that would warrant further
investigation with respect to Kansas SO2 emission sources
that might contribute to problems with attainment of the 2010
SO2 NAAQS.
Kansas also included information on mobile source emissions and
population in its border counties. Kansas indicated that SO2
emissions from mobile sources are controlled through federally mandated
fuel standards which limit sulfur concentrations at the refinery level.
Kansas notes that mobile emissions are disbursed in small quantities
over large geographic areas leading to greater dispersion before
crossing state borders. Additionally, Kansas expects further reductions
in SO2 emissions from this sector as the EPA continues to
regulate emissions from mobile sources along with regular fleet
turnover to cleaner vehicles. The EPA agrees that because emissions
from non-point sources in other source categories such as mobile
emissions are more dispersed throughout the State, emissions from other
source categories such as mobile sources are less likely to cause high
ambient concentrations when compared to a point source on a ton-for-ton
basis.
In conclusion, for interstate transport prong 1, we reviewed
ambient SO2 monitoring data and available information for
SO2 emission sources within 50 km of the Kansas border, as
well as available modeling results for
[[Page 31652]]
sources in Kansas and in adjacent states within 50 km of the Kansas
border. Based on this analysis, we propose to determine that Kansas
will not significantly contribute to nonattainment of the 2010
SO2 NAAQS in any other state, per the requirements of CAA
section 110(a)(2)(D)(i)(I).
3. The EPA's Prong 2 Evaluation
In its prong 2 analysis, Kansas reviewed potential SO2
impacts on designated maintenance areas. The EPA interprets CAA section
110(a)(2)(D)(i)(I) 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,
rather than only former nonattainment, and thus current maintenance,
areas. Kansas also performed a prong 2 analysis based on the EPA's
interpretation, noting that monitors located near Kansas in neighboring
states showed very low levels of SO2, emissions in Kansas
and neighboring states have decreased indicating they should not be
considered to have maintenance issues for this NAAQS. Kansas also
referenced federal regulations which have resulted in and will continue
to result in SO2 emissions decreases in Kansas and
neighboring states.
The EPA has reviewed Kansas' analysis and other available
information on SO2 air quality, including federally
enforceable regulations and emission trends to evaluate the state's
conclusion that Kansas will not interfere with maintenance of the 2010
SO2 NAAQS in downwind states. This evaluation builds on the
analysis regarding significant contribution to nonattainment (prong 1),
which evaluated monitored ambient concentrations of SO2 in
Kansas and neighboring states, available modeling results, and the
large distances between cross-state SO2 sources, the EPA is
proposing to find that SO2 levels in neighboring states near
the Kansas border do not indicate any inability to maintain the
SO2 NAAQS that could be attributed in part to sources in
Kansas. As shown in Table 1, the statewide SO2 emissions
from Kansas and neighboring states have decreased substantially over
time, per our review of the EPA's emissions trends data.\33\ From 2000
to 2019, total statewide SO2 emissions decreased by the
following proportions: Colorado (85% decrease), Kansas (83% decrease),
Missouri (72% decrease), Nebraska (40% decrease), and Oklahoma (68%
decrease). This trend of decreasing SO2 emissions does not
by itself demonstrate that areas in Kansas and neighboring states will
not have issues maintaining the 2010 SO2 NAAQS. However, as
a piece of this weight of evidence analysis for prong 2, it provides
further indication (when considered alongside low monitor values in
neighboring states as depicted in Table 2) that such maintenance issues
are unlikely. This is because the geographic scope of these reductions
and their large sizes strongly suggest that they are not transient
effects from reversible causes, and thus these reductions suggest that
there is very low likelihood that a strong upward trend in emissions
will occur that might cause areas presently in attainment to violate
the NAAQS. These reductions have been caused by regulatory requirements
in Kansas and the downwind states and by economic factors, such as low
natural gas prices and the increasing supply of renewable energy, that
are not likely to be reversed.\34\
---------------------------------------------------------------------------
\33\ Additional emissions trends data are available at: https://www.epa.gov/air-emissions-inventories/air-pollutant-emissions-trends-data.
\34\ Kansas provided information on emission reductions and
control equipment for certain sources in its SIP and the EPA
summarized this information in its prong 1 analysis.
---------------------------------------------------------------------------
Kansas also identified EPA programs which, either directly or
indirectly, have significantly reduced SO2 emissions in
Kansas. These programs include: The Acid Rain program; the Cross-State
Air Pollution Rule (CSAPR); Prevention of Significant Deterioration
(PSD)/New Source Review (NSR) Permitting Programs; Heavy-Duty Diesel
Rule; Mercury and Air Toxic Standards Rule (MATS); \35\ Regional Haze;
\36\ Nonroad Diesel Rule; and the EPA's Tier 2 Motor Vehicle Emissions
Standards and Gasoline Sulfur Control Requirements Rule. The EPA agrees
that the federal regulations identified by Kansas have helped to reduce
SO2 emissions from various sources in Kansas in addition to
other federal regulations as detailed here. The EPA's Acid Rain Program
set a permanent cap on the total amount of SO2 that may be
emitted by electric generating units (EGUs) in the contiguous United
States.\37\ CSAPR requires significant reductions in SO2
emissions from power plants in the eastern half of the United States,
including Kansas and neighboring states.\38\ MATS requires reductions
of emissions of heavy metals which, as a co-benefit, reduce emissions
of SO2, and establishes alternative numeric emission
standards, including SO2 (as an alternate to hydrochloric
acid).\39\ The EPA's Nonroad Diesel Rule will reduce sulfur levels from
about 3,000 parts per million (ppm) to 15 ppm when fully
implemented.\40\ The EPA's Heavy-Duty Engine and Vehicle Standards and
Highway Diesel Fuel Sulfur Control Requirements (Heavy-Duty Diesel
Rule) required refiners to start producing diesel fuel for use in
highway vehicles with a sulfur content of no more than 15 ppm as of
June 1, 2006.\41\ NSPS for various source categories, including but not
limited to Industrial-Commercial-Institutional Steam Generating Units;
\42\ Sulfuric Acid Plants; \43\ Stationary Gas and Combustion Turbines;
\44\ Portland Cement Manufacturing; \45\ Electric Utility Steam
Generating Units (Boilers); \46\ and Onshore Natural Gas
Processing,\47\ establish standards which reduce SO2
emissions.
---------------------------------------------------------------------------
\35\ See 77 FR 9304.
\36\ See 64 FR 35714.
\37\ See 40 CFR parts 72 through 78.
\38\ See 40 CFR part 97. See also 76 FR 48208.
\39\ See 40 CFR parts 60 and 63. See also 77 FR 9304.
\40\ See 40 CFR parts 9, 69, 80, 86, 89, 94, 1039, 1048, 1051,
1065, and 1068. See also 69 FR 38958.
\41\ See 40 CFR parts 69, 80, and 86. See also 66 FR 5002.
\42\ See 40 40 CFR part 60, subpart Da and 40 CFR part 63. See
also 77 FR 9304.
\43\ See 40 CFR part 60, subparts A, D, E, F, G and H. See also
36 FR 24876.
\44\ See 40 CFR part 60, subparts GG and KKKK. See also 71 FR
38482 and 44 FR 52792
\45\ See 40 CFR parts 60 and 63. See also 75 FR 54970.
\46\ See 40 CFR part 60, subpart Da and 40 CFR part 63. See also
77 FR 9304.
\47\ See 40 CFR part 60, subpart LLL. See also 77 FR 49490.
---------------------------------------------------------------------------
In addition, the EPA's Tier 3 Motor Vehicle Emission and Fuel
Standards Rule \48\ also reduce SO2 emissions by
establishing gasoline sulfur standards that reduce SO2
emissions from certain types of mobile sources. The EPA finds that
these federal measures have and continue to lower SO2
emissions, which, in turn, are expected to continue to support the
EPA's proposed conclusion that SO2 emissions from Kansas
will not contribute significantly to nonattainment or interfere with
maintenance of the 2010 1-hour SO2 NAAQS in another state.
---------------------------------------------------------------------------
\48\ See 40 CFR parts 79, 80, 85, 86, 600, 1036, 1037, 1039,
1042, 1048, 1054, 1065, and 1066. See also 79 FR 23414.
---------------------------------------------------------------------------
As noted in Kansas' submission, any future large sources of
SO2 emissions will be addressed by Kansas' SIP-approved
Prevention of Significant Deterioration (PSD) program.\49\ Future minor
sources of SO2 emissions will be addressed by Kansas' minor
new source review permit program.\50\ The permitting regulations
contained within these programs should help ensure that
[[Page 31653]]
ambient concentrations of SO2 in neighboring states are not
exceeded as a result of new facility construction or modification
occurring in Kansas.
---------------------------------------------------------------------------
\49\ See EPA's final action of the PSD portions of Kansas' SIP,
at 80 FR 32017, June 4, 2015.
\50\ Id.
---------------------------------------------------------------------------
As previously mentioned, Kansas evaluated its potential impacts to
the Jackson County, Missouri nonattainment area located near the Kansas
border. As discussed in the EPA's prong 1 analysis, the modeling for
the Jackson County area's clean data determination included sources in
Kansas and did not show substantial impacts from Kansas sources to the
Missouri area. Additionally, the EPA has determined the area attained
the NAAQS through a clean data determination with the monitor in the
area still showing values well below the level of the standard. For
these reasons, the EPA finds that emissions from Kansas do not
interfere with maintenance of the NAAQS in the Jackson County area as
the area is not exhibiting difficulties in maintaining the standard.
In conclusion, for interstate transport prong 2, we reviewed
additional information about SO2 air quality and emission
trends and Kansas' permitting regulations, as well as the technical
information considered for interstate transport prong 1. We find that
the combination of low ambient concentrations of SO2 in
Kansas and neighboring states, the available modeling results, the
large distances between cross-state SO2 sources, the
downward trend in SO2 emissions from Kansas and neighboring
states, and state measures that prevent new facility construction or
modification in Kansas from causing SO2 exceedances in
downwind states, indicates no interference with maintenance of the 2010
SO2 NAAQS in other states. Accordingly, we propose to
determine that Kansas SO2 emission sources will not
interfere with maintenance of the 2010 SO2 NAAQS in any
other state, per the requirements of CAA section 110(a)(2)(D)(i)(I).
B. Nebraska
1. State's Analysis
In its SIP, Nebraska conducted a weight of evidence analysis to
examine whether SO2 emissions from Nebraska adversely affect
attainment or maintenance of the 2010 SO2 NAAQS in downwind
states.\51\ Nebraska evaluated potential air quality impacts on areas
outside the state through an assessment of whether SO2
emissions from sources located within 50 km of Nebraska's borders may
have associated interstate transport impacts. The State's analysis
included SO2 emissions information in the state, with
specific focus on sources and counties located within 50 km of
Nebraska's borders. For the seven sources which emitted greater than
100 tons per year of SO2 located within 50 km of Nebraska's
borders, Nebraska provided an in-depth analysis by assessing current
permitted emissions rates and existing control technologies. Nebraska
also reviewed meteorological conditions representative of
SO2 sources near the state's border, and the distances from
identified SO2 sources in Nebraska to the nearest area that
is not attaining the NAAQS or may have trouble maintaining the NAAQS in
another state. Nebraska also reviewed statewide emissions and ambient
air monitoring trends. Based on this weight of evidence analysis,
Nebraska concluded that emissions within the state will not contribute
to nonattainment or interfere with maintenance of the 2010
SO2 NAAQS in neighboring states. Nebraska also noted that
SO2 emissions within the state have been steadily decreasing
over time, specifically noting a 49.7% decrease in point source
emissions between 2006 and 2019. With regard to the interference with
maintenance requirement, Nebraska discussed the low monitored ambient
concentrations of SO2 in neighboring states in the period up
to and including 2019. Based on this weight of evidence analysis,
Nebraska concluded that emissions within the state will not
significantly contribute to nonattainment or interfere with maintenance
of the 2010 SO2 NAAQS in neighboring states.
---------------------------------------------------------------------------
\51\ See Nebraska's SO2 interstate transport SIP as
submitted in October 2020 in the docket for this action.
---------------------------------------------------------------------------
2. The EPA's Prong 1 Evaluation
The EPA proposes to find that Nebraska's SIP meets the interstate
transport requirements of CAA section 110(a)(2)(D)(i)(I), prong 1 for
the 2010 SO2 NAAQS, as discussed below. To support our
proposal, we completed a weight of evidence analysis which considers an
evaluation of ambient air quality data and of available information for
certain emission sources near the Nebraska border, as well as available
modeling results for sources in Nebraska or neighboring states within
50 km of Nebraska's borders. Based on that analysis, we propose to find
that Nebraska will not significantly contribute to nonattainment of the
2010 SO2 NAAQS in any other state.
To assess ambient air quality, the EPA reviewed monitoring data in
Nebraska and neighboring states to see whether there were any
monitoring sites, particularly near the Nebraska border, with elevated
SO2 concentrations that might warrant further investigation
with respect to interstate transport of SO2 from emission
sources in Nebraska to a neighboring state near any given monitor. We
reviewed 2017-2019 SO2 design value concentrations at
monitors with data sufficient to produce valid 1-hour SO2
design values for Nebraska and neighboring states.\52\ In Table 2, we
have included all monitors in each neighboring state and in Nebraska
within 50 km of the Nebraska border. As shown, there are no violating
design values at monitors in Nebraska or neighboring states within 50
km of the state border. One area bordering Nebraska--Woodbury County,
Iowa--has been designated unclassifiable. Later in this section, the
EPA discusses modeling available for Woodbury County, Iowa (See Table
10). There are no other areas designated as unclassifiable located
within 50 km of Nebraska's borders. For these reasons and for reasons
discussed later in this section, the EPA is proposing to find that
emissions from Nebraska will not contribute significantly to
nonattainment in any other state.
---------------------------------------------------------------------------
\52\ Id.
---------------------------------------------------------------------------
The data presented in Table 2 show that there are three Nebraska
monitors located within 50 km of a neighboring state's border, and
these monitors indicate design values between 32% to 55% of the NAAQS.
One SO2 monitor was installed in Nebraska as a source-
oriented monitor (AQS Site ID: 310550057) and was sited to characterize
the Omaha Public Power District's (OPPD) North Omaha Station (North
Omaha), which is located in Douglas County, Nebraska and is within 50
km of the Nebraska border with Iowa. The EPA designated Douglas County
as attainment/unclassifiable as part of the Round 4 designations for
the 2010 1-hour NAAQS.\53\ Table 8 provides the 3-year design value
used to characterize the impacts from North Omaha. The 2017-2019 design
value is 34 ppb, which is 45% of the 2010 SO2 NAAQS and
provides evidence that there is not an air quality problem around the
North Omaha facility. Therefore, it is unlikely that the North Omaha
facility could significantly contribute to nonattainment of the 2010 1-
hour SO2 NAAQS in the nearby State of Iowa. In its SIP,
Nebraska noted that the North Omaha facility currently operates two
coal-fired units, using low-sulfur coal;
[[Page 31654]]
these units are to be converted to natural gas by 2023. Three coal-
fired units were retired in 2016 which resulted in a significant
SO2 emissions decrease in that year. The emissions trends
for this source are shown in Table 3. Nebraska also referenced the low
design values at the monitors located in Omaha (as shown in Table 2)
between the North Omaha facility and the Walter Scott Jr. facility in
Iowa that similarly support the claim that the North Omaha facility is
not causing or contributing to violations of the NAAQS in Iowa.\54\ The
North Omaha facility was also included in a modeling demonstration for
a nearby Iowa source. That modeling is discussed later in this section
and provides further evidence that there are no violations in Iowa to
which the North Omaha facility could contribute.
---------------------------------------------------------------------------
\53\ See TSD Chapter 2: Final Round 4 Area Designations for the
2010 1-Hour SO2 Primary National Ambient Air Quality
Standard for Areas without Violating Monitors, at https://www.epa.gov/sites/production/files/2020-12/documents/02-rd4_so2d_tsd_for_areas_without_violating_monitors.pdf.
\54\ For locations of monitors in relation to the sources in
Nebraska and Iowa, please see map on page 21 of Nebraska's SIP as
contained in the docket for this action.
Table 8--Nebraska Sources With a Source-Oriented Monitor Within 50 km of Another State
--------------------------------------------------------------------------------------------------------------------------------------------------------
Distance from 2017-2019
2020 emissions source to monitor 3-year
Nebraska source County (tons) Nebraska/Iowa Site ID design value
border (km) (ppb)
--------------------------------------------------------------------------------------------------------------------------------------------------------
OPPD North Omaha................................ Douglas........................... 5,447 0.3 310550057 34
--------------------------------------------------------------------------------------------------------------------------------------------------------
There is one monitor in a neighboring state located within 50 km of
the Nebraska border, in Sioux City, South Dakota, and this monitor
recorded an SO2 design value of 3 ppb, or 4% of the 2010
SO2 NAAQS. Thus, these air quality data do not, by
themselves, indicate any particular location that would warrant further
investigation with respect to SO2 emission sources that
might significantly contribute to nonattainment in the bordering
states. However, because the monitoring network is not necessarily
designed \55\ to find all locations of high SO2
concentrations, this observation indicates an absence of evidence of
impact at these locations but is not sufficient evidence by itself of
an absence of impact at all locations in the neighboring states. We
have therefore also conducted a source-oriented analysis.
---------------------------------------------------------------------------
\55\ State monitoring networks must meet the minimum monitoring
requirements contained in appendix D to 40 CFR part 58.
Specifically, section 4.4 of appendix D outlines the minimum
monitoring requirements for SO2 monitoring based on
population weighted emissions. Monitors sited to meet the minimum
monitoring requirements are sited for a number of reasons (e.g.,
measuring a source's maximum contribution, measuring background
concentrations, monitoring population exposure, etc.) and may not
necessarily capture maximum impacts from specific sources. However,
data from these monitors may still provide useful evidence in the
context of interstate transport.
---------------------------------------------------------------------------
In the next step of our weight of evidence analysis, the EPA
evaluated available modeling results for sources in Nebraska and in the
adjacent states that are within 50 km of the Nebraska border. The
purpose of evaluating modeling for sources in Nebraska within 50 km of
the Nebraska border is to determine whether these sources are, either
on their own or in conjunction with other sources near the border,
impacting a violation of the 2010 1-hour SO2 NAAQS in
another state. The purpose of evaluating modeling results in adjacent
states within 50 km of the Nebraska border is to ascertain whether
there are any modeled violations in neighboring states to which sources
in Nebraska could potentially be contributing.
Table 9 provides a summary of the modeling results for one source
in Nebraska for which we have available modeling information and is
located within 50 km of another state: Omaha Public Power District's
(OPPD) Nebraska City Station (Nebraska City).\56\ The modeling analysis
for Nebraska City resulted in no modeled violations of the 2010 1-hour
SO2 NAAQS within the modeling domain. The emissions trends
for this source are included in Table 3. The most recent available
annual emissions at Nebraska City are also provided in Table 9, and the
EPA has verified that the most recent annual emissions are below the
annual emissions from the years modeled for Nebraska City. The nearest
source in a neighboring state emitting greater than 100 tpy is the
Walter Scott Jr., Energy Center, located 66 km North of Nebraska City.
In its SIP, Nebraska indicated that Nebraska City is comprised of two
coal-fired units, one of which (Unit 2) is fitted with a dry flue gas
desulfurization (scrubber) system to control SO2 emissions.
Emissions at Nebraska City have decreased approximately 36% from 2014.
Based on the large distance between cross-state sources, the localized
nature of SO2, and the available modeling information, the
EPA agrees that Nebraska City is not likely contributing to violations
in Iowa as there are no modeled air quality violations in Iowa.
---------------------------------------------------------------------------
\56\ See the EPA's Technical Support Document for its Intended
Round 2 Designations for the 2010 SO2 NAAQS for Nebraska
available at: https://www.epa.gov/sites/production/files/2016-03/documents/ne-epa-tsd-r2.pdf and the EPA's Technical Support Document
for its Final Round 2 Designations for the 2010 SO2 NAAQS
for Nebraska available at: https://www.epa.gov/sites/production/files/2016-07/documents/r7_ne_final_designation_tsd_06302016.pdf.
Table 9--Nebraska Source With Modeling Data Located Within 50 km of Another State
--------------------------------------------------------------------------------------------------------------------------------------------------------
Distance from Modeled 99th
2020 source to Other facilities percentile 1-hour Model grid extends
Nebraska source County emissions Nebraska border included in modeling SO2 maximum into another state?
(tons) (km) concentration (ppb)
--------------------------------------------------------------------------------------------------------------------------------------------------------
OPPD Nebraska City............... Otoe................. 11,480 0.62 None................. 32.7 (based on 2012- Yes (Fremont
2014 actual County, Iowa).
emissions).
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 31655]]
Table 10 provides a summary of the available modeling results for
the modeled sources in neighboring states which are located within 50
km of Nebraska: Mid-American Energy--George Neal North (George Neal
North), Mid-American Energy George Neal South (George Neal South) and
Mid-American Energy Walter Scott Jr. Energy Center (Walter Scott Jr.)
in Iowa. The Round 2 1-hour SO2 designations modeling for
Woodbury County, Iowa explicitly included George Neal North and George
Neal South and no other SO2 sources in the area, and
included portions of Nebraska in the modeling domain.\57\ In 2016, the
EPA designated Woodbury County, Iowa as unclassifiable, because even
though the modeling demonstrated attainment for the area, some emission
rates used in the modeling analysis, specifically the emission rates
for MidAmerican Energy Company's George Neal North Units 1 and 2 were
not yet federally enforceable at the time of the final Round 2
designations (in June 2016). In September 2016, Iowa rescinded the
permits for George Neal North Units 1 and 2 as they were permanently
retired.\58\ Therefore, the EPA can consider the Round 2 modeling
demonstration for the purpose of evaluating potential transport as the
emissions rates assumed in the modeling have since become federally
enforceable.\59\ The North Omaha Station is located over 100 km from
the George Neal facilities in Iowa. Specifically, there are no sources
of SO2 emitting over 10 tpy in Nebraska located within 50 km
of George Neal North and George Neal South, providing further evidence
that Nebraska emissions are not causing or contributing to violations
in Woodbury County, Iowa.
---------------------------------------------------------------------------
\57\ See the EPA's Technical Support Document for its Intended
Round 2 Designations for the 2010 SO2 NAAQS for Iowa
available at: https://www.epa.gov/sites/production/files/2016-03/documents/ia-epa-tsd-r2.pdf and the EPA's Technical Support Document
for its Final Round 2 Designations for the 2010 SO2 NAAQS
for Iowa available at: https://www.epa.gov/sites/production/files/2016-07/documents/r7_ia_final_designation_tsd_06302016.pdf.
\58\ See docket document containing letter from MidAmerican
Energy dated April 18, 2016, requesting the permits for George Neal
North Units 1 and 2 be rescinded and Iowa's response letter dated
September 9, 2016, indicating the permits for these units were
revoked.
\59\ The modeling for the George Neal facilities resulted in a
maximum impact near the level of the NAAQS; however, because this
modeling was based on maximum allowable emissions prior to the
shutdown of Units 1 and 2 and included a background concentration,
the EPA finds this to be a conservative estimate of actual air
quality in the Woodbury County area not an indication of potential
air quality issues to which Nebraska sources could contribute.
---------------------------------------------------------------------------
The modeling submitted by Iowa for Walter Scott Jr. in
Pottawattamie County based on a set of hybrid (i.e., a mix of allowable
and 2012-2014 actual) emissions for Walter Scott Jr. and the OPPD North
Omaha Station located in Nebraska resulted in a maximum impact of 51.1
ppb, or 68% of the level of the NAAQS.\60\ The modeling demonstrates
maximum impacts below the level of the NAAQS and thereby provides
evidence that Nebraska emissions are not causing or contributing to
violations in the area of Pottawattamie County, Iowa around Walter
Scott Jr. As depicted in Figure 19 of the EPA's Technical Support
Document for its Intended Round 3 Designations for the 2010
SO2 NAAQS for Iowa, the maximum modeled impact is located to
the Southeast of the Walter Scott Jr. facility.\61\ The North Omaha
Station is located approximately 19 km from the Walter Scott Jr.
facility. As previously mentioned, Nebraska also referenced the low
design values at the monitors located in Omaha (as shown in Table 2)
between the North Omaha facility and the Walter Scott Jr. facility in
Iowa that similarly support the claim that the North Omaha facility is
not causing or contributing to violations of the NAAQS in Iowa.\62\
Based on the distance between cross-state sources, the localized nature
of SO2 and the available modeling and monitoring information
for the area, the EPA agrees that the North Omaha Station is not likely
to cause or contribute to violations in Iowa as there are no air
quality violations in the nearby area in Iowa.
---------------------------------------------------------------------------
\60\ See the EPA's Technical Support Document for its Intended
Round 3 Designations for the 2010 SO2 NAAQS for Iowa
available at: https://www.epa.gov/sites/production/files/2017-08/documents/14_ia_so2_rd3-final.pdf and the EPA's Technical Support
Document for its Final Round 3 Designations for the 2010
SO2 NAAQS for Iowa available at: https://www.epa.gov/sites/production/files/2017-12/documents/14-ia-so2-rd3-final.pdf.
\61\ See Id.
\62\ For locations of monitors in relation to the sources in
Nebraska and Iowa, please see map on page 21 of Nebraska's SIP as
contained in the docket for this action.
---------------------------------------------------------------------------
The most recent available annual emissions of these identified
sources in nearby states are also provided in Table 10, and the EPA has
verified that the most recent annual emissions are below the annual
emissions from the years modeled at each source.\63\
---------------------------------------------------------------------------
\63\ Nebraska also included emissions trends for certain sources
in neighboring states in Table 5 of its SIP which depicts the
downward trend in emissions at these sources as well. See Nebraska's
SIP submittal included in the docket for this action.
Table 10--Other States' Sources With Modeling Data Located Within 50 km of Nebraska
--------------------------------------------------------------------------------------------------------------------------------------------------------
Distance from Modeled 99th
2020 source to Other facilities percentile 1-hour Model grid extends
Other state source County emissions Nebraska border included in SO2 maximum into another state?
(tons) (km) modeling concentration (ppb)
--------------------------------------------------------------------------------------------------------------------------------------------------------
George Neal North................ Woodbury, Iowa...... 1,660 0.2 George Neal South 74.3 (Allowable Yes (Dakota and
(Iowa). Emissions). Thurston Counties,
Nebraska).
George Neal South................ Woodbury, Iowa...... 1,203 0.8 George Neal North 74.3 (Allowable Yes (Dakota and
(Iowa). Emissions). Thurston Counties,
Nebraska).
Walter Scott Jr.................. Pottawattamie, Iowa. 5,960 0.1 OPPD North Omaha 51.1 (Hybrid of Yes (Douglas and
(Nebraska). Actual and Sarpy Counties,
Allowable Emissions Nebraska).
for 2012-2014).
--------------------------------------------------------------------------------------------------------------------------------------------------------
The EPA proposes to find that the modeling results summarized in
Tables 9 and 10, which provide evidence that air quality near certain
larger sources in other states is attaining the NAAQS, when weighed
along with the other factors in this document, support the EPA's
proposed conclusion that sources in Nebraska will not significantly
[[Page 31656]]
contribute to nonattainment of the 2010 1-hour SO2 NAAQS in
any other state.
The next step in our weight of evidence analysis, is to assess
certain other sources near the border for which we do not have
available modeling or monitoring data. As noted in section III of this
document, the EPA finds that it is appropriate to examine the impacts
of emissions from stationary sources in Nebraska in distances ranging
from 0 km to 50 km from the facility, based on the ``urban scale''
definition contained in appendix D to 40 CFR part 58, section 4.4.
Nebraska assessed point sources up to 50 km from neighboring state
borders to evaluate trends and SO2 concentrations in area-
wide air quality The list of sources emitting 100 tpy \64\ or more of
SO2 within 50 km from state borders without available
modeling data is shown in Table 11.
---------------------------------------------------------------------------
\64\ Nebraska limited its analysis to Nebraska sources of
SO2 emitting at least 100 tpy. We agree with Nebraska's
choice to limit its analysis in this way, because in the absence of
special factors, for example the presence of a nearby larger source,
a high concentration of small sources in an area, or unusual
physical factors, Nebraska sources emitting less than 100 tpy can
appropriately be presumed to not be causing or contributing to
SO2 concentrations above the NAAQS.
Table 11--Nebraska SO2 Sources Without Available Modeling Data Near Neighboring States
----------------------------------------------------------------------------------------------------------------
Distance to Neighboring
2019 SO2 Distance to nearest state source
Nebraska source Facility ID emissions Nebraska neighboring 2019
(tons) border (km) state SO2 emissions
source (km) (tons)
----------------------------------------------------------------------------------------------------------------
Clean Harbors Environmental 7768011 205.9 15 95 174.7
Services, Inc. (HollyFrontier
Cheyenne
Refinery,
Wyoming).
Western Sugar Cooperative..... 7767911 144.7 35 107 (Basin [caret]5261
Electric Power
Cooperative--La
ramie River
Station,
Wyoming).
Ash Grove Cement Co........... 7287311 681.4 24 33 (MidAmerican [caret]5960
Energy Co.--
Walter Scott
Jr., Iowa).
Douglas Co Recycling Landfill. 7699311 164.6 25 41 (MidAmerican [caret]5960
Energy Co.--
Walter Scott
Jr., Iowa).
Lon D Wright Power Plant...... 7766111 [caret]587.9 33 59 (MidAmerican [caret]5960
Energy Co.--
Walter Scott
Jr., Iowa).
----------------------------------------------------------------------------------------------------------------
[caret] Based on 2020 emissions.
Table 12--Neighboring State SO2 Sources Near Nebraska *
----------------------------------------------------------------------------------------------------------------
Distance to Nebraska
2019 SO2 Distance to nearest Nebraska source 2020
Source Facility ID emissions Nebraska SO2 source (km) emissions
(tons) border (km) (tons)
----------------------------------------------------------------------------------------------------------------
Exide Technologies Canon 8230311 158.5 7.2 80 (OPPD 11,480
Hollow (Missouri). Nebraska City
Station).
----------------------------------------------------------------------------------------------------------------
* Table 12 does not include sources duplicative of Table 11.
As shown, there are two Nebraska sources (Ash Grove Cement Company
and Douglas County Recycling Landfill) located within 50 kilometers of
a cross-state source, MidAmerican Energy Co.--Walter Scott Jr., located
in the State of Iowa. As previously discussed and shown in Table 10,
modeling submitted to the EPA by the State of Iowa for the
Pottawattomie County area, containing Walter Scott Jr., indicates that
the highest predicted 99th percentile daily maximum 1-hour
concentration within the modeling domain is 51.1 ppb. Additionally, as
shown in Table 8, the most recent 3-year design value for Douglas
County, Nebraska, containing the North Omaha Station is 34 ppb.
Nebraska evaluated available meteorological data to determine the
wind patterns near Ash Grove Cement Company and Douglas County
Recycling Landfill. For the Ash Grove Cement Company, Nebraska included
a wind rose for the Plattsmouth airport that depicts the predominant
wind pattern in the area as being in a Southeast-Northwest pattern
which would blow emissions away from the Walter Scott Jr. facility in
Iowa.\65\ For the Douglas County Recycling Landfill, Nebraska included
a wind rose for the Omaha/Eppley airport that depicts the predominant
wind pattern in the area as being in a South-Southeast and North-
Northwest wind pattern which would keep emissions from Douglas County
Recycling Landfill in Nebraska.\66\ Nebraska also referenced the low
design values at the monitors located in Omaha (as shown in Table 2)
between the Douglas County Recycling Landfill and the Walter Scott Jr.
facility in Iowa that similarly support the claim that the Douglas
County Recycling Landfill is not causing or contributing to violations
of the NAAQS in Iowa. Based on the respective distances from Ash Grove
Cement Company and Douglas County Recycling Landfill to the Nebraska
border, the localized nature of SO2, and the general wind
patterns in the area as referenced by Nebraska, the EPA agrees that it
is unlikely these Nebraska sources could on their own cause or
contribute to a violation in the neighboring State of Iowa.
---------------------------------------------------------------------------
\65\ See page 24 of Nebraska's SO2 Transport SIP
Submittal included in the docket for this action for the wind rose
referenced by Nebraska.
\66\ See page 32 of Nebraska's SO2 Transport SIP
Submittal included in the docket for this action for the wind rose
referenced by Nebraska.
---------------------------------------------------------------------------
For the remaining three Nebraska sources listed in Table 11, there
are no cross-state sources located within 50 km of the Nebraska source
meaning it is unlikely there is an air quality problem in the
neighboring state to which the Nebraska sources could contribute.
Additionally, based on the distance from each Nebraska source to the
border along with the localized nature of SO2, the EPA finds
it unlikely that these sources could on their own cause or contribute
to a violation in any other state. As shown in Table 12, Exide
Technologies in Missouri is located 7
[[Page 31657]]
km from the Nebraska border; however, there are no Nebraska sources
within 50 km which could contribute to a potential air quality problem
in Missouri near the Exide facility.
In conclusion, for interstate transport prong 1, we reviewed
ambient SO2 monitoring data and SO2 emissions
information as well as available modeling information for sources both
within Nebraska and in neighboring states within 50 km of Nebraska's
borders. Based on this analysis, we propose to determine that Nebraska
will not significantly contribute to nonattainment of the 2010
SO2 NAAQS in any other state, per the requirements of CAA
section 110(a)(2)(D)(i)(I).
3. The EPA's Prong 2 Evaluation
In its prong 2 analysis, Nebraska reviewed potential SO2
impacts on designated maintenance areas. The EPA interprets CAA section
110(a)(2)(D)(i)(I) 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,
rather than only former nonattainment, and thus current maintenance,
areas. Nebraska also performed a prong 2 analysis based on the EPA's
interpretation, noting that monitors located near Nebraska in
neighboring states showed very low levels of SO2 and
emissions in Nebraska and neighboring states have decreased, indicating
they should not be considered to have maintenance issues for this
NAAQS.
The EPA has reviewed Nebraska's analysis and other available
information on SO2 air quality and emission trends to
evaluate the state's conclusion that Nebraska will not interfere with
maintenance of the 2010 SO2 NAAQS in downwind states. This
evaluation builds on the analysis regarding significant contribution to
nonattainment (prong 1), which evaluated monitored ambient
concentrations of SO2 in Nebraska and neighboring states,
available modeling results, the distances between cross-state
SO2 sources, and other factors. The EPA is proposing to find
that SO2 levels in neighboring states near the Nebraska
border do not indicate any inability to maintain the SO2
NAAQS that could be attributed in part to sources in Nebraska.
As shown in Table 1, the statewide SO2 emissions from
Nebraska and neighboring states have decreased substantially over time,
per our review of the EPA's emissions trends data.\67\ From 2000 to
2019, total statewide SO2 emissions decreased by the
following proportions: Colorado (85% decrease), Iowa (76% decrease),
Kansas (83% decrease), Missouri (72% decrease), Nebraska (40%
decrease), South Dakota (88% decrease) and Wyoming (70% decrease). This
trend of decreasing SO2 emissions does not by itself
demonstrate that areas in Nebraska and neighboring states will not have
issues maintaining the 2010 SO2 NAAQS. However, as a piece
of this weight of evidence analysis for prong 2, it provides further
indication (when considered alongside low monitor values in neighboring
states as depicted in Table 2) that such maintenance issues are
unlikely. This is because the geographic scope of these reductions and
their large sizes strongly suggest that they are not transient effects
from reversible causes, and thus these reductions suggest that there is
very low likelihood that a strong upward trend in emissions will occur
that might cause areas presently in attainment to violate the NAAQS.
These reductions have been caused by regulatory requirements in
Nebraska and the downwind states and by economic factors, such as low
natural gas prices and the increasing supply of renewable energy, that
are not likely to be reversed.\68\
---------------------------------------------------------------------------
\67\ Additional emissions trends data are available at: https://www.epa.gov/air-emissions-inventories/air-pollutant-emissions-trends-data.
\68\ Nebraska provided information on emission reductions and
control equipment for certain sources in its SIP and the EPA
summarized this information in its prong 1 analysis.
---------------------------------------------------------------------------
The EPA also evaluated federal regulations which have helped to
reduce SO2 emissions from various sources in Nebraska and
neighboring states. The EPA's Acid Rain Program set a permanent cap on
the total amount of SO2 that may be emitted by EGUs in the
contiguous United States.\69\ CSAPR requires significant reductions in
SO2 emissions from power plants in the eastern half of the
United States, including Nebraska and neighboring states.\70\ MATS
requires reductions of emissions of heavy metals which, as a co-
benefit, reduce emissions of SO2, and establishes
alternative numeric emission standards, including SO2 (as an
alternate to hydrochloric acid).\71\ The EPA's Nonroad Diesel Rule will
reduce sulfur levels from about 3,000 parts per million (ppm) to 15 ppm
when fully implemented.\72\ The EPA's Heavy-Duty Engine and Vehicle
Standards and Highway Diesel Fuel Sulfur Control Requirements (Heavy-
Duty Diesel Rule) required refiners to start producing diesel fuel for
use in highway vehicles with a sulfur content of no more than 15 ppm as
of June 1, 2006.\73\ NSPS for various source categories, including but
not limited to Industrial-Commercial-Institutional Steam Generating
Units; \74\ Sulfuric Acid Plants; \75\ Stationary Gas and Combustion
Turbines; \76\ Portland Cement Manufacturing; \77\ Electric Utility
Steam Generating Units (Boilers); \78\ and Onshore Natural Gas
Processing,\79\ establish standards which reduce SO2
emissions.
---------------------------------------------------------------------------
\69\ See 40 CFR parts 72 through 78.
\70\ See 40 CFR part 97. See also 76 FR 48208.
\71\ See 40 CFR parts 60 and 63. See also 77 FR 9304.
\72\ See 40 CFR parts 9, 69, 80, 86, 89, 94, 1039, 1048, 1051,
1065, and 1068. See also 69 FR 38958.
\73\ See 40 CFR parts 69, 80, and 86. See also 66 FR 5002.
\74\ See 40 CFR part 60, subpart Da and 40 CFR part 63. See also
77 FR 9304.
\75\ See 40 CFR part 60, subparts A, D, E, F, G and H. See also
36 FR 24876.
\76\ See 40 CFR part 60, subparts GG and KKKK. See also 71 FR
38482 and 44 FR 52792.
\77\ See 40 CFR parts 60 and 63. See also 75 FR 54970.
\78\ See 40 CFR part 60, subpart Da and 40 CFR part 63. See also
77 FR 9304.
\79\ See 40 CFR part 60, subpart LLL. See also 77 FR 49490.
---------------------------------------------------------------------------
In addition, the EPA's Tier 3 Motor Vehicle Emission and Fuel
Standards Rule \80\ also reduce SO2 emissions by
establishing gasoline sulfur standards that reduce SO2
emissions from certain types of mobile sources. The EPA finds that
these federal measures have and continue to lower SO2
emissions, which, in turn, are expected to continue to support the
EPA's proposed conclusion that SO2 emissions from Nebraska
will not contribute significantly to nonattainment or interfere with
maintenance of the 2010 1-hour SO2 NAAQS in another state.
---------------------------------------------------------------------------
\80\ See 40 CFR parts 79, 80, 85, 86, 600, 1036, 1037, 1039,
1042, 1048, 1054, 1065, and 1066. See also 79 FR 23414.
---------------------------------------------------------------------------
As noted in Nebraska's submission, any future large sources of
SO2 emissions will be addressed by Nebraska's SIP-approved
PSD program.\81\ Future minor sources of SO2 emissions will
be addressed by Nebraska's minor new source review permit program.\82\
The permitting regulations contained within these programs should help
ensure that ambient concentrations of SO2 in neighboring
states are not exceeded as a result of new facility construction or
modification occurring in Nebraska.
---------------------------------------------------------------------------
\81\ See EPA's final action of the PSD portions of Nebraska's
SIP, at 83 FR 14179, April 2, 2018.
\82\ Id.
---------------------------------------------------------------------------
In conclusion, for interstate transport prong 2, we reviewed
additional information about SO2 air quality and emission
trends, federal regulations, and Nebraska's permitting regulations, as
well as the technical information
[[Page 31658]]
considered for interstate transport prong 1. We find that the
combination of low ambient concentrations of SO2 in Nebraska
and neighboring states, available modeling results, the distances
between cross-state SO2 sources, the downward trend in
SO2 emissions from Nebraska and surrounding states, and
state measures that prevent new facility construction or modification
in Nebraska from causing SO2 exceedances in downwind states,
indicates no interference with maintenance of the 2010 SO2
NAAQS from Nebraska in other states. Accordingly, we propose to
determine that Nebraska SO2 emission sources will not
interfere with maintenance of the 2010 SO2 NAAQS in any
other state, per the requirements of CAA section 110(a)(2)(D)(i)(I).
V. Requirements for Approval of a SIP Revision
The State submissions have met the public notice requirements for
SIP submissions in accordance with 40 CFR 51.102. The submissions also
satisfied the completeness criteria of 40 CFR part 51, appendix V.
Kansas provided public notice on its SIP revision from January 16,
2020, to February 17, 2020, and received no comments. Nebraska provided
public notice on its SIP revision from September 14, 2020, to October
16, 2020, and received no comments. In addition, the revision meets the
substantive SIP requirements of the CAA, including section 110 and
implementing regulations.
VI. Proposed Action
The EPA is proposing to approve the following submittals as meeting
the interstate transport requirements of CAA section 110(a)(2)(D)(i)(I)
for the 2010 SO2 NAAQS: Kansas' April 7, 2020 submittal and
Nebraska's October 27, 2020 submittal. The EPA is proposing this
approval based on our review of the information and analysis provided
by each state, as well as additional relevant information, which
indicates that in-state air emissions will not contribute significantly
to nonattainment or interfere with maintenance of the 2010
SO2 NAAQS in any other state. This action is being taken
under section 110 of the CAA.
VII. Statutory and Executive Order Reviews
Under the Clean Air Act, the Administrator is required to approve a
SIP submission that complies with the provisions of the Act and
applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a).
Thus, in reviewing SIP submissions, the EPA's role is to approve state
choices, provided that they meet the criteria of the CAA. Accordingly,
these proposed actions merely approve state law as meeting federal
requirements and do not impose additional requirements beyond those
imposed by state law. For that reason, these proposed actions:
Are not significant regulatory actions subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993);
Do not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
Are 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.);
Do 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);
Do not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
Are not economically significant regulatory actions based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
Are not significant regulatory actions subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
Are not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because this action does not involve technical standards; and
Do not provide the EPA with the discretionary authority to
address, as appropriate, disproportionate human health or environmental
effects, using practicable and legally permissible methods, under
Executive Order 12898 (59 FR 7629, February 16, 1994).
In addition, these SIPs are 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 in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Particulate
matter, Reporting and recordkeeping requirements, Sulfur dioxide,
Volatile organic compounds.
Authority: 42 U.S.C. 7401 et seq.
Dated: June 8, 2021.
Edward H. Chu,
Acting Regional Administrator, Region 7.
For the reasons stated in the preamble, the EPA proposes to amend
40 CFR part 52 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 R--Kansas
0
2. In Sec. 52.870, the table in paragraph (e) is amended by adding the
entry ``(46)'' in numerical order to read as follows:
Sec. 52.870 Identification of plan.
* * * * *
(e) * * *
EPA-Approved Kansas Nonregulatory Provisions
----------------------------------------------------------------------------------------------------------------
State
Name of nonregulatory SIP Applicable geographic submittal EPA approval date Explanation
provision or nonattainment area date
----------------------------------------------------------------------------------------------------------------
* * * * * * *
(46) Section 110(a)(2)(D)(i)(I)-- Statewide............... 4/7/2020 [Date of [EPA-R07-OAR-2021-
significant contribution to publication of 0365; FRL-10024-
nonattainment (prong 1), and final rule in the 81-Region 7].
interfering with maintenance of Federal This action
the NAAQs (prong 2) (Interstate Register], addresses the
Transport) Infrastructure [Federal Register following CAA
Requirements for the 2010 SO2 citation of the elements:
NAAQS. final rule]. 110(a)(2)(D)(i)(I
)--prongs 1 and
2.
----------------------------------------------------------------------------------------------------------------
[[Page 31659]]
Subpart CC--Nebraska
0
3. In Sec. 52.1420, the table in paragraph (e) is amended by adding
the entry ``(37)'' in numerical order to read as follows:
Sec. 52.1420 Identification of plan.
* * * * *
(e) * * *
EPA-Approved Nebraska Nonregulatory Provisions
----------------------------------------------------------------------------------------------------------------
State
Name of nonregulatory SIP Applicable geographic or submittal EPA approval date Explanation
provision nonattainment area date
----------------------------------------------------------------------------------------------------------------
* * * * * * *
(37) Section 110(a)(2)(D)(i)(I)-- Statewide............... 10/27/2020 [Date of [EPA-R07-OAR-2021-
significant contribution to publication of 0365; FRL-10024-
nonattainment (prong 1), and final rule in the 81-Region 7].
interfering with maintenance of Federal This action
the NAAQs (prong 2) (Interstate Register], addresses the
Transport) Infrastructure [Federal Register following CAA
Requirements for the 2010 SO2 citation of the elements:
NAAQS. final rule]. 110(a)(2)(D)(i)(I
)--prongs 1 and
2.
----------------------------------------------------------------------------------------------------------------
[FR Doc. 2021-12501 Filed 6-14-21; 8:45 am]
BILLING CODE 6560-50-P
