[Federal Register Volume 83, Number 132 (Tuesday, July 10, 2018)]
[Proposed Rules]
[Pages 31915-31939]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-14737]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-HQ-OAR-2018-0225; FRL-9980-53-OAR]
RIN 2060-AT92


Determination Regarding Good Neighbor Obligations for the 2008 
Ozone National Ambient Air Quality Standard

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing to determine that the Cross-State Air 
Pollution Rule Update for the 2008 ozone National Ambient Air Quality 
Standards (NAAQS) (CSAPR Update) fully addresses certain states' 
obligations under Clean Air Act (CAA) section 110(a)(2)(D)(i)(I) 
regarding interstate pollution transport for the 2008 ozone NAAQS. The 
CSAPR Update, published on October 26, 2016, promulgated Federal 
Implementation Plans (FIPs) for 22 states in the eastern U.S. In the 
final CSAPR Update, based on information available at that time, the 
EPA could not conclude that the rule fully addressed CAA section 
110(a)(2)(D)(i)(I) obligations for 21 of the 22 CSAPR Update states. 
This action proposes a determination that, based on additional 
information and analysis, the CSAPR Update fully addresses this CAA 
provision for the 2008 ozone NAAQS for all remaining CSAPR Update 
states. Specifically, EPA proposes to determine

[[Page 31916]]

that there will be no remaining nonattainment or maintenance receptors 
in the eastern U.S. in 2023. Therefore, with the CSAPR Update fully 
implemented, these states are not expected to contribute significantly 
to nonattainment in, or interfere with maintenance by, any other state 
with regard to the 2008 ozone NAAQS. In accord with this proposed 
determination, the EPA proposes to determine that it has no 
outstanding, unfulfilled obligation under CAA section 110(c)(1) to 
establish additional requirements for sources in these states to 
further reduce transported ozone pollution under CAA section 
110(a)(2)(D)(i)(I) with regard to the 2008 ozone NAAQS. As a result of 
this finding, this action proposes minor revisions to the existing 
CSAPR Update regulations to reflect that the CSAPR Update FIPs fully 
address CAA section 110(a)(2)(D)(i)(I). The proposed determination 
would apply to states currently subject to CSAPR Update FIPs as well as 
any states for which EPA has approved replacement of CSAPR Update FIPs 
with CSAPR Update SIPs.

DATES: Comments must be received on or before August 31, 2018.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2018-0225, at http://www.regulations.gov. Follow the online 
instructions for submitting comments. 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 http://www2.epa.gov/dockets/commenting-epa-dockets.
    Public hearing. The EPA will be holding one public hearing on the 
proposed Determination Regarding Good Neighbor Obligations for the 2008 
Ozone National Ambient Air Quality Standard. The hearing will be held 
to accept oral comments on the proposal. The hearing will be held on 
August 1, 2018 in Washington DC. The hearing will begin at 9:00 a.m. 
(local time) and will conclude at 6:00 p.m. (local time) or two hours 
after the last registered speaker. The hearing will be held at the 
Environmental Protection Agency, William Jefferson Clinton East 
Building, Main Floor Room 1153, 1201 Constitution Avenue NW, in 
Washington, DC 20460. Because this hearing is being held at a U.S. 
government facility, individuals planning to attend the hearing should 
be prepared to show valid picture identification to the security staff 
in order to gain access to the meeting room. No large signs will be 
allowed in the building, cameras may only be used outside of the 
building, and demonstrations will not be allowed on federal property 
for security reasons. The EPA website for the rulemaking, which 
includes the proposal and supporting materials, can be found at https://www.epa.gov/airmarkets/proposed-csapr-close-out.
    If you would like to present oral testimony at the public hearing, 
please register online at https://www.epa.gov/airmarkets/forms/public-hearing-proposed-csapr-close-out or contact Mr. Brian Fisher, U.S. 
Environmental Protection Agency, Office of Atmospheric Programs, Clean 
Air Markets Division, (MS 6204-M), 1200 Pennsylvania Avenue NW, 
Washington, DC 20460, telephone (202) 343 9633, email address is 
[email protected], no later than 2 business days prior to the public 
hearing. If using email, please provide the following information: Time 
you wish to speak (morning, afternoon, evening), name, affiliation, 
address, email address, and telephone number.

FOR FURTHER INFORMATION CONTACT: Brian Fisher, Clean Air Markets 
Division, Office of Atmospheric Programs, U.S. Environmental Protection 
Agency, MC 6204M, 1200 Pennsylvania Avenue NW, Washington, DC 20460; 
telephone number: (202) 343-9633; email address: [email protected].

SUPPLEMENTARY INFORMATION:
    Regulated entities. Entities regulated under the CSAPR Update are 
fossil fuel-fired boilers and stationary combustion turbines that serve 
generators producing electricity for sale, including combined cycle 
units and units operating as part of systems that cogenerate 
electricity and other useful energy output. Regulated categories and 
entities include:

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                                 NAICS *      Examples of potentially
            Category               code        regulated industries
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Industry.......................   221112  Fossil fuel-fired electric
                                           power generation.
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* North American Industry Classification System.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated. To 
determine whether your facility is affected by this action, you should 
carefully examine the applicability provisions in 40 CFR 97.804. If you 
have questions regarding the applicability of the CSAPR Update to a 
particular entity, consult the person listed in the FOR FURTHER 
INFORMATION CONTACT section above.
    Outline. The following outline is provided to aid in locating 
information in this preamble.

I. General Information
    States Covered by This Action
II. Background and Legal Authority
    A. Ground-Level Ozone Pollution and Public Health
    B. The EPA's Statutory Authority for This Proposed Action
    C. Good Neighbor Obligations for the 2008 Ozone NAAQS
    D. Summary of the CSAPR Update
III. Proposed Determination Regarding Good Neighbor Obligations for 
the 2008 Ozone NAAQS
    A. Analytic Approach
    B. Selection of a Future Analytic Year
    1. Attainment Dates for the 2008 Ozone NAAQS
    2. Feasibility of Control Strategies To Reduce Ozone Season 
NOX
    3. Focusing on 2023 for Analysis
    C. Air Quality Analysis
    1. Definition of Nonattainment and Maintenance Receptors
    2. Overview of Air Quality Modeling Platform
    3. Emissions Inventories
    4. Air Quality Modeling To Identify Nonattainment and 
Maintenance Receptors
    5. Pollutant Transport From Upwind States
    D. Proposed Determination
IV. Statutory Authority and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review, and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 13771: Reducing Regulations and Controlling 
Regulatory Costs
    C. Paperwork Reduction Act
    D. Regulatory Flexibility Act
    E. Unfunded Mandates Reform Act
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments

[[Page 31917]]

    H. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    I. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    J. National Technology Transfer Advancement Act
    K. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    L. Determinations Under Section 307(b)(1) and (d)

I. General Information

    Within this document ``we,'' ``us,'' or ``our'' should be 
interpreted to mean the U.S. EPA.

Where can I get a copy of this document and other related information?

    The EPA has established a docket for this action under Docket ID 
No. EPA-HQ-OAR-2018-0225 (available at http://www.regulations.gov). 
Information related to the proposed action and the public hearing is 
available at the website: https://www.epa.gov/airtransport.

States Covered by This Action

    In the CSAPR Update, 81 FR 74504 (Oct. 26, 2016), the EPA 
promulgated FIPs intended to address 22 eastern states' obligations 
under CAA section 110(a)(2)(D)(i)(I), also known as the ``good neighbor 
provision,'' with respect to the 2008 ozone NAAQS. The good neighbor 
provision requires upwind states to control their emissions that impact 
air quality problems in downwind states. Based on information available 
when the CSAPR Update was finalized, the EPA was unable to determine at 
that time that the FIPs fully addressed good neighbor obligations under 
this NAAQS for 21 of the 22 states. The EPA has subsequently proposed 
to approve a draft SIP which, if finalized, would fully address the 
good neighbor obligation for one of these states, Kentucky. In this 
action, the EPA proposes to determine that, with CSAPR Update 
implementation, the 20 remaining states' good neighbor obligations for 
the 2008 ozone NAAQS are fully addressed. In accord with this 
determination, the EPA would have no further obligation under CAA 
section 110(c) to establish requirements for power plants or any other 
emissions sources in these states to further reduce transported ozone 
pollution under CAA section 110(a)(2)(D)(i)(I) with regard to this 
NAAQS.
    The two states among the 22 CSAPR Update states that are not 
covered by this action are Tennessee and Kentucky. With respect to 
Tennessee, the EPA already determined in the final CSAPR Update that 
implementation of the state's emissions budget would fully eliminate 
the state's significant contribution to downwind nonattainment and 
interference with maintenance of the 2008 ozone NAAQS because the 
downwind air quality problems to which the state was linked were 
projected to be resolved after implementation of the CSAPR Update. 81 
FR 74540. With respect to Kentucky, the EPA has proposed in a separate 
action to approve the state's draft SIP submittal demonstrating that no 
additional emissions reductions beyond those required by the CSAPR 
Update are necessary to address the state's good neighbor obligation 
with respect to the 2008 ozone NAAQS. 83 FR 17123 (April 18, 2018). See 
Table I.A-1 for a list of states covered by this proposal.

  Table I.A-1--States Covered by This Proposed Determination Regarding
           Good Neighbor Obligations for the 2008 Ozone NAAQS
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                                  State
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Alabama.
Arkansas.
Illinois.
Indiana.
Iowa.
Kansas.
Louisiana.
Maryland.
Michigan.
Mississippi.
Missouri.
New Jersey.
New York.
Ohio.
Oklahoma.
Pennsylvania.
Texas.
Virginia.
West Virginia.
Wisconsin.
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II. Background and Legal Authority

A. Ground-Level Ozone Pollution and Public Health

    Ground-level ozone causes a variety of negative effects on human 
health, vegetation, and ecosystems. In humans, acute and chronic 
exposure to ozone is associated with premature mortality and a number 
of morbidity effects, such as asthma exacerbation. In ecosystems, ozone 
exposure causes visible foliar injury in some plants, decreases growth 
in some plants, and affects ecosystem community composition.\1\
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    \1\ For more information on the human health and welfare and 
ecosystem effects associated with ambient ozone exposure, see the 
EPA's October 2015 Regulatory Impact Analysis of the Final Revisions 
to the National Ambient Air Quality Standards for Ground-Level Ozone 
(EPA-452/R-15-007) in the docket for this rule and also found in the 
docket for the 2015 ozone NAAQS, Docket No. EPA-HQ-OAR-2013-0169-
0057.
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    In this proposed action, consistent with previous rulemakings 
described in section II.B, the EPA relies on analysis that reflects the 
regional nature of transported ground-level ozone pollution. Ground-
level ozone is not emitted directly into the air, but is a secondary 
air pollutant created by chemical reactions between nitrogen oxides 
(NOX), carbon monoxide (CO), methane (CH4), and 
non-methane volatile organic compounds (VOCs) in the presence of 
sunlight. Emissions from mobile sources, electric generating units 
(EGUs), industrial facilities, gasoline vapors, and chemical solvents 
are some of the major anthropogenic sources of ozone precursors. 
NOX emissions from the mobile source category lead all 
sectors and were more than double emissions from the second-highest 
emitting sector, and accounted from more than half of the national 
NOX emissions in 2014.\2\ The potential for ground-level 
ozone formation increases during periods with warmer temperatures and 
stagnant air masses. Therefore, ozone levels are generally higher 
during the summer months.3 4 Ground-level ozone 
concentrations and temperature are highly correlated in the eastern 
U.S., with observed ozone increases of 2-3 parts per billion (ppb) per 
degree Celsius reported.\5\
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    \2\ EPA. 2014 National Emissions Inventory (NEI) v2. Released 2/
2018 and available at https://www.epa.gov/air-emissions-inventories.
    \3\ Rasmussen, D.J. et al. (2011). Ground-level ozone-
temperature relationships in the eastern US: A monthly climatology 
for evaluating chemistry-climate models. Atmospheric Environment 47: 
142-153.
    \4\ High ozone concentrations have also been observed in cold 
months, where a few areas in the western U.S. have experienced high 
levels of local VOC and NOX emissions that have formed 
ozone when snow is on the ground and temperatures are near or below 
freezing.
    \5\ Bloomer, B.J., J.W. Stehr, C.A. Piety, R.J. Salawitch, and 
R.R. Dickerson (2009). Observed relationships of ozone air pollution 
with temperature and emissions, Geophys. Res. Lett., 36, L09803.
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    Precursor emissions can be transported downwind directly or, after 
transformation in the atmosphere, as ozone. Studies have established 
that ozone formation, atmospheric residence, and transport occur on a 
regional scale (i.e., hundreds of miles) over much of the eastern U.S. 
As a result of ozone transport, in any given location, ozone pollution 
levels are impacted by a combination of local emissions and emissions 
from upwind sources. Numerous observational studies have

[[Page 31918]]

demonstrated the transport of ozone and its precursors and the impact 
of upwind emissions on high concentrations of ozone pollution.\6\
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    \6\ Bergin, M.S. et al. (2007). Regional air quality: local and 
interstate impacts of NOX and SO2 emissions on 
ozone and fine particulate matter in the eastern United States. 
Environmental Sci & Tech. 41: 4677-4689.
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    The EPA concluded in several previous rulemakings (summarized in 
section II.B) that interstate ozone transport can be an important 
component of peak ozone concentrations during the summer ozone season 
and that NOX control strategies are effective for reducing 
regional-scale ozone transport. Model assessments have looked at 
impacts on peak ozone concentrations after potential emissions 
reduction scenarios for NOX and VOCs for NOX-
limited and VOC-limited areas. For example, Jiang and Fast concluded 
that NOX emissions reduction strategies are effective in 
lowering ozone mixing ratios in urban areas and Liao et al. showed that 
NOX reductions result in lower peak ozone concentrations in 
non-attainment areas in the Mid-Atlantic.\7\ Assessments of ozone 
conducted for the October 2015 Regulatory Impact Analysis of the Final 
Revisions to the National Ambient Air Quality Standards for Ground-
Level Ozone (EPA-452/R-15-007) also show the importance of 
NOX emissions on ozone formation. This analysis is in the 
docket for this rule and also can be found in the docket for the 2015 
ozone NAAQS regulatory impact analysis, Docket No. EPA-HQ-OAR-2013-0169 
(document ID EPA-HQ-OAR-2013-0169-0057).
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    \7\ Jiang, G.; Fast, J.D. (2004). Modeling the effects of VOC 
and NOX emission sources on ozone formation in Houston 
during the TexAQS 2000 field campaign. Atmospheric Environment 38: 
5071-5085.
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    Studies have found that NOX emissions reductions can be 
effective in reducing ozone pollution as quantified by the form of the 
2008 ozone standard, 8-hour peak concentrations. Specifically, studies 
have found that NOX emissions reductions from EGUs, mobile 
sources, and other source categories can be effective in reducing the 
upper-end of the cumulative ozone distribution in the summer on a 
regional scale.\8\ Analysis of air quality monitoring data trends shows 
reductions in summertime ozone concurrent with implementation of 
NOX reduction programs.\9\ Gilliland et al. examined the 
NOX SIP Call and presented reductions in observed versus 
modeled ozone concentrations in the eastern U.S. downwind from major 
NOX sources.\10\ The results showed significant reductions 
in ozone concentrations (10-25 percent) from observed measurements 
(CASTNET and AQS) \11\ between 2002 and 2005, linking reductions in EGU 
NOX emissions from upwind states with ozone reductions 
downwind of the major source areas.\12\ Additionally, G[eacute]go et 
al. showed that ground-level ozone concentrations were significantly 
reduced after implementation of the NOX SIP Call.\13\
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    \8\ Hidy, G.M. and Blanchard C.L. (2015). Precursor reductions 
and ground-level ozone in the Continental United States. J. of Air & 
Waste Management Assn. 65, 10.
    \9\ Simon, H. et al. (2015). Ozone trends across the United 
States over a period of decreasing NOX and VOC emissions. 
Environmental Science & Technology 49, 186-195.
    \10\ Gilliland, A.B. et al. (2008). Dynamic evaluation of 
regional air quality models: Assessing changes in O3 
stemming from changes in emissions and meteorology. Atmospheric 
Environment 42: 5110-5123.
    \11\ CASTNET is the EPA's Clean Air Status and Trends Network. 
AQS is the EPA's Air Quality System.
    \12\ Hou, Strickland & Liao. ``Contributions of regional air 
pollutant emissions to ozone and fine particulate matter-related 
mortalities in eastern U.S. urban areas''. Environmental Research, 
Feb. 2015. Available at https://ac.els-cdn.com/S0013935114004113/1-s2.0-S0013935114004113-main.pdf?_tid=78c88101-fa6e-4e75-a65c-f56746905e7d&acdnat=1525175812_0e62553b83c9ffa1105aa306a478e8bb
    \13\ G[eacute]go et al. (2007). Observation-based assessment of 
the impact of nitrogen oxides emissions reductions on O3 
air quality over the eastern United States. J. of Applied 
Meteorology and Climatology 46: 994-1008.
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    Mobile sources also account for a large share of the NOX 
emissions inventory (i.e., about 7.3 million tons per year in the 2011 
base year, which represented more than 50% of continental U.S. 
NOX emissions), and the EPA recognizes that emissions 
reductions achieved from this sector as well can reduce transported 
ozone pollution. The EPA has national programs that serve to reduce 
emissions from all contributors to the mobile source inventory (i.e., 
projected NOX emissions reductions of about 4.7 million tons 
per year between the 2011 base year and the 2023 future analytical 
year). A detailed discussion of the EPA's mobile source emissions 
reduction programs can be found at www.epa.gov/otaq.
    In light of the regional nature of ozone transport discussed 
herein, and given that NOX emissions from mobile sources are 
being addressed in separate national rules, in the CSAPR Update (as in 
previous regional ozone transport actions) the EPA relied on regional 
analysis and required regional ozone-season NOX emissions 
reductions from EGUs to address interstate transport of ozone.

B. The EPA's Statutory Authority for This Proposed Action

    The statutory authority for this proposed action is provided by the 
CAA as amended (42 U.S.C. 7401 et seq.). Specifically, sections 110 and 
301 of the CAA provide the primary statutory underpinnings for this 
rule. The most relevant portions of section 110 are subsections 
110(a)(1), 110(a)(2) (including 110(a)(2)(D)(i)(I)), and 110(c)(1).
    Section 110(a)(1) provides that states must make SIP submissions 
``within 3 years (or such shorter period as the Administrator may 
prescribe) after the promulgation of a national primary ambient air 
quality standard (or any revision thereof),'' and that these SIP 
submissions are to provide for the ``implementation, maintenance, and 
enforcement'' of such NAAQS.\14\ The statute directly imposes on states 
the duty to make these SIP submissions, and the requirement to make the 
submissions is not conditioned upon the EPA taking any action other 
than promulgating a new or revised NAAQS.\15\
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    \14\ 42 U.S.C. 7410(a)(1).
    \15\ See EPA v. EME Homer City Generation, L.P., 134 S. Ct. 
1584, 1601 (2014).
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    The EPA has historically referred to SIP submissions made for the 
purpose of satisfying the applicable requirements of CAA sections 
110(a)(1) and 110(a)(2) as ``infrastructure SIP'' submissions. Section 
110(a)(1) addresses the timing and general requirements for 
infrastructure SIP submissions, and section 110(a)(2) provides more 
details concerning the required content of these submissions. It 
includes a list of specific elements that ``[e]ach such plan'' 
submission must address.\16\ All states, regardless of whether the 
state includes areas designated as nonattainment for the relevant 
NAAQS, must have SIPs that meet the applicable requirements of section 
110(a)(2), including provisions of section 110(a)(2)(D)(i)(I) described 
later and that are the focus of this rule.
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    \16\ The EPA's general approach to infrastructure SIP 
submissions is explained in greater detail in individual notices 
acting or proposing to act on state infrastructure SIP submissions 
and in guidance. See, e.g., Memorandum from Stephen D. Page on 
Guidance on Infrastructure State Implementation Plan (SIP) Elements 
under Clean Air Act Sections 110(a)(1) and 110(a)(2) (Sept. 13, 
2013).
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    Section 110(c)(1) requires the Administrator to promulgate a FIP at 
any time within two years after the Administrator: (1) Finds that a 
state has failed to make a required SIP submission; (2) finds a SIP 
submission to be incomplete pursuant to CAA section 110(k)(1)(C); or 
(3) disapproves

[[Page 31919]]

a SIP submission, unless the state corrects the deficiency through a 
SIP revision that the Administrator approves before the FIP is 
promulgated.\17\
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    \17\ 42 U.S.C. 7410(c)(1).
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    Section 110(a)(2)(D)(i)(I), also known as the ``good neighbor 
provision,'' provides the primary basis for this action. It requires 
that each state SIP shall include provisions sufficient to ``prohibit[ 
] . . . any source or other type of emissions activity within the State 
from emitting any air pollutant in amounts which will--(I) contribute 
significantly to nonattainment in, or interfere with maintenance by, 
any other State with respect to any [NAAQS].'' \18\
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    \18\ 42 U.S.C. 7410(a)(2)(D)(i)(I).
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    The EPA has previously issued four rules interpreting and 
clarifying the requirements of section 110(a)(2)(D)(i)(I) for states in 
the eastern United States. These rules, and the associated court 
decisions addressing these rules, summarized here, provide important 
guidance regarding the requirements of section 110(a)(2)(D)(i)(I).
    The NOX SIP Call, promulgated in 1998, addressed the 
good neighbor provision for the 1979 1-hour ozone NAAQS.\19\ The rule 
required 22 states and the District of Columbia to amend their SIPs to 
reduce NOX emissions that contribute to ozone nonattainment 
in downwind states. The EPA set an ozone season NOX budget 
for each covered state, essentially a cap on ozone season 
NOX emissions in the state. Covered states were given the 
option to participate in a regional cap-and-trade program, known as the 
NOX Budget Trading Program (NBP), to achieve a large portion 
of the reductions. The United States Court of Appeals for the District 
of Columbia Circuit (D.C. Circuit) largely upheld the NOX 
SIP Call in Michigan v. EPA, 213 F.3d 663 (D.C. Cir. 2000), cert. 
denied, 532 U.S. 904 (2001).
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    \19\ 63 FR 57356 (Oct. 27, 1998). As originally promulgated, the 
NOX SIP Call also addressed good neighbor obligations 
under the 1997 8-hour ozone NAAQS, but the EPA subsequently stayed 
the rule's provisions with respect to that standard. 40 CFR 
51.121(q).
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    The EPA's next rule addressing the good neighbor provision, Clean 
Air Interstate Rule (CAIR), was promulgated in 2005 and addressed both 
the 1997 PM2.5 and 1997 ozone NAAQS.\20\ CAIR required SIP 
revisions in 28 states and the District of Columbia to reduce emissions 
of sulfur dioxide (SO2) and/or NOX--important 
precursors of regionally transported PM2.5 (SO2 
and NOX) and ozone (NOX). As in the 
NOX SIP Call, states were given the option to participate in 
regional cap-and-trade programs to achieve the reductions. When the EPA 
promulgated the final CAIR in May 2005, the EPA also issued a national 
rule, finding that states had failed to submit SIPs to address the 
requirements of CAA section 110(a)(2)(D)(i) with respect to the 1997 
PM2.5 and 1997 ozone NAAQS. Those states were required by 
the CAA to have submitted good neighbor SIPs for those standards by 
July 2000 (i.e., three years after the standards were finalized).\21\ 
These findings of failure to submit triggered a 2-year clock for the 
EPA to issue FIPs to address interstate transport,\22\ and on March 15, 
2006, the EPA promulgated FIPs to ensure that the emissions reductions 
required by CAIR would be achieved on schedule.\23\ CAIR was remanded 
to the EPA by the D.C. Circuit in North Carolina v. EPA, 531 F.3d 896 
(D.C. Cir. 2008), modified on reh'g, 550 F.3d 1176. For more 
information on the legal issues underlying CAIR and the D.C. Circuit's 
holding in North Carolina, refer to the preamble of the original 
CSAPR.\24\
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    \20\ 70 FR 25162 (May 12, 2005).
    \21\ 70 FR 21147 (May 12, 2005). See n.14 and main text, supra.
    \22\ See n.17 and main text, supra.
    \23\ 71 FR 25328 (April 28, 2006).
    \24\ 76 FR 48208, 48217 (Aug. 8, 2011).
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    In 2011, the EPA promulgated the original CSAPR to address the 
issues raised by the remand of CAIR. CSAPR addressed the two NAAQS at 
issue in CAIR and additionally addressed the good neighbor provision 
for the 2006 PM2.5 NAAQS.\25\ CSAPR required 28 states to 
reduce SO2 emissions, annual NOX emissions, and/
or ozone season NOX emissions that significantly contribute 
to other states' nonattainment or interfere with other states' 
abilities to maintain these air quality standards. To align 
implementation with the applicable attainment deadlines, the EPA 
promulgated FIPs for each of the 28 states covered by CSAPR. The FIPs 
implement regional cap-and-trade programs to achieve the necessary 
emissions reductions. Each state can submit a good neighbor SIP at any 
time that, if approved by the EPA, would replace the CSAPR FIP for that 
state.\26\ CSAPR was the subject of an adverse decision by the D.C. 
Circuit in August 2012,\27\ reversed in April 2014 by the Supreme 
Court,\28\ which largely upheld the rule, including EPA's approach to 
addressing interstate transport in CSAPR, but remanded to the D.C. 
Circuit to consider other claims not addressed by the Court. EPA v. EME 
Homer City Generation, L.P., 134 S. Ct. 1584 (2014). On remand from the 
Supreme Court, in July 2015 the D.C. Circuit affirmed the EPA's 
interpretation of various statutory provisions and the EPA's technical 
decisions. EME Homer City Generation, L.P. v. EPA, 795 F.3d 118 (2015) 
(EME Homer City II). However, the court also remanded the rule without 
vacatur for reconsideration of the EPA's emissions budgets for certain 
states, which the court found may over-control those states' emissions 
with respect to the downwind air quality problems to which the states 
were linked. Id. at 129-30, 138. For more information on the legal 
considerations of CSAPR and the court's decisions in the EME Homer City 
litigation, refer to the preamble of the CSAPR Update.\29\
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    \25\ 76 FR 48208.
    \26\ EPA has already approved SIPs fully replacing the original 
CSAPR FIPs for Alabama, 81 FR 59869 (Aug. 31, 2016), Georgia, 82 FR 
47930 (Oct. 13, 2017), and South Carolina, 82 FR 47936 (Oct. 13, 
2017).
    \27\ On August 21, 2012, the D.C. Circuit issued a decision in 
EME Homer City Generation, L.P. v. EPA, 696 F.3d 7 (D.C. Cir. 2012) 
(EME Homer I), vacating CSAPR. The EPA sought review with the D.C. 
Circuit en banc and the D.C. Circuit declined to consider the EPA's 
appeal en banc. EME Homer City Generation, L.P. v. EPA, No. 11-1302 
(D.C. Cir. January 24, 2013), ECF No. 1417012 (denying the EPA's 
motion for rehearing en banc).
    \28\ On January 23, 2013, the Supreme Court granted the EPA's 
petition for certiorari. EPA v. EME Homer City Generation, L.P., 133 
S. Ct. 2857 (2013) (granting the EPA's and other parties' petitions 
for certiorari). On April 29, 2014, the Supreme Court issued a 
decision reversing the D.C. Circuit's EME Homer City opinion.
    \29\ 81 FR 74511.
---------------------------------------------------------------------------

    In 2016, the EPA promulgated the CSAPR Update to address interstate 
transport of ozone pollution with respect to the 2008 ozone NAAQS. The 
final rule generally updated the CSAPR ozone season NOX 
emissions budgets for 22 states to achieve cost-effective 
NOX emissions reductions from EGUs within those states.\30\ 
The CSAPR Update implemented these budgets through FIPs requiring 
sources to participate in a revised CSAPR ozone season NOX 
allowance trading program. As under the original CSAPR, each state can 
submit a good neighbor SIP at any time that, if approved by the EPA, 
would replace the CSAPR Update FIP for that state.\31\ The final CSAPR 
Update also addressed the remand by the D.C. Circuit of certain states' 
original CSAPR phase 2 ozone season NOX emissions budgets in 
EME Homer City II. The CSAPR Update is subject to pending

[[Page 31920]]

legal challenges in the D.C. Circuit. Wisconsin v. EPA, No. 16-1406 
(D.C. Cir. filed Nov. 23, 2016). Further information about the CSAPR 
Update can be found in section II.D of this notice.
---------------------------------------------------------------------------

    \30\ One state, Kansas, was made newly subject to a CSAPR ozone 
season NOX requirement by the CSAPR Update. All other 
CSAPR Update states were already subject to ozone season 
NOX requirements under the original CSAPR.
    \31\ EPA has already approved a SIP fully replacing the CSAPR 
Update FIP for Alabama. 82 FR 46674 (Oct. 6, 2017).
---------------------------------------------------------------------------

    Section 301(a)(1) of the CAA also gives the Administrator the 
general authority to prescribe such regulations as are necessary to 
carry out functions under the Act.\32\ Pursuant to this section, the 
EPA has authority to clarify the applicability of CAA requirements. In 
this action, among other things, the EPA is clarifying the 
applicability of section 110(a)(2)(D)(i)(I) with respect to the 2008 
ozone NAAQS. In particular, the EPA is using its authority under 
sections 110 and 301 to make a determination that no further 
enforceable reductions in emissions of NOX are required 
under this provision with respect to the 2008 ozone NAAQS for the 
states covered by this rule. The EPA is making minor revisions to the 
existing state-specific sections of the CSAPR Update regulations for 
all states covered by that action other than Kentucky and Tennessee.
---------------------------------------------------------------------------

    \32\ 42 U.S.C. 7601(a)(1).
---------------------------------------------------------------------------

C. Good Neighbor Obligations for the 2008 Ozone NAAQS

    On March 12, 2008, the EPA promulgated a revision to the NAAQS, 
lowering both the primary and secondary standards to 75 ppb. See 
National Ambient Air Quality Standards for Ozone, Final Rule, 73 FR 
16436 (March 27, 2008). Specifically, the standards require that an 
area may not exceed 75 ppb using the 3-year average of the fourth 
highest 24-hour maximum 8-hour rolling average ozone concentration. 
These revisions of the NAAQS, in turn, triggered a 3-year deadline for 
states to submit SIP revisions addressing infrastructure requirements 
under CAA sections 110(a)(1) and 110(a)(2), including the good neighbor 
provision. Several events affected application of the good neighbor 
provision for the 2008 ozone NAAQS, including reconsideration of the 
2008 ozone NAAQS and legal developments pertaining to the EPA's 
original CSAPR, which created uncertainty surrounding the EPA's 
statutory interpretation and implementation of the good neighbor 
provision.\33\ Notwithstanding these events, EPA ultimately affirmed 
that states' good neighbor SIPs were due on March 12, 2011.
---------------------------------------------------------------------------

    \33\ These events are described in detail in section IV.A.2 of 
the CSAPR Update. 81 FR 74515.
---------------------------------------------------------------------------

    The EPA subsequently took several actions that triggered the EPA's 
obligation under CAA section 110(c) to promulgate FIPs addressing the 
good neighbor provision for several states.\34\ First, on July 13, 
2015, the EPA published a rule finding that 24 states failed to make 
complete submissions that address the requirements of section 
110(a)(2)(D)(i)(I) related to the interstate transport of pollution as 
to the 2008 ozone NAAQS. See 80 FR 39961 (effective August 12, 2015). 
The finding action triggered a 2-year deadline for the EPA to issue 
FIPs to address the good neighbor provision for these states by August 
12, 2017. The CSAPR Update finalized FIPs for 13 of these states 
(Alabama, Arkansas, Illinois, Iowa, Kansas, Michigan, Mississippi, 
Missouri, Oklahoma, Pennsylvania, Tennessee, Virginia, and West 
Virginia). The EPA also determined in the CSAPR Update that the Agency 
had fully satisfied its FIP obligation as to nine additional states 
identified in the finding of failure to submit (Florida, Georgia, 
Maine, Massachusetts, Minnesota, New Hampshire, North Carolina, South 
Carolina, and Vermont). The EPA determined that these states did not 
contribute significantly to nonattainment in, or interfere with 
maintenance by, any other state with respect to the 2008 ozone NAAQS. 
81 FR 74506.\35\ On June 15, 2016 and July 20, 2016, the EPA published 
additional rules finding that New Jersey and Maryland, respectively, 
also failed to submit transport SIPs for the 2008 ozone NAAQS. See 81 
FR 38963 (June 15, 2016) (effective July 15, 2016); 81 FR 47040 (July 
20, 2016) (Maryland, effective August 19, 2016). The finding actions 
triggered 2-year deadlines for the EPA to issue FIPs to address the 
good neighbor provision for Maryland by August 19, 2018, and New Jersey 
by July 15, 2018. The CSAPR Update finalized FIPs for these two states.
---------------------------------------------------------------------------

    \34\ This section of the preamble focuses on SIP and FIP actions 
for those states addressed in the CSAPR Update. The EPA has also 
acted on SIPs for other states not mentioned in this action. The 
memorandum, Status of 110(a)(2)(D)(i)(I) SIPs for the 2008 Ozone 
NAAQS, more fully describes the good neighbor SIP status for the 
2008 ozone NAAQS and is available in the docket for this action.
    \35\ The two remaining states addressed in the findings of 
failure to submit (California and New Mexico) were not part of the 
CSAPR Update analysis and are not addressed in this rulemaking.
---------------------------------------------------------------------------

    In addition to the previously identified finding actions, the EPA 
also finalized disapproval or partial disapproval actions for SIPs 
submitted by Indiana, Kentucky, Louisiana, New York, Ohio, Texas, and 
Wisconsin.\36\ These disapprovals triggered the EPA's obligation to 
promulgate FIPs to implement the requirements of the good neighbor 
provision for those states within 2 years of the effective date of each 
disapproval. The EPA promulgated CSAPR Update FIPs for Indiana, 
Kentucky, Louisiana, New York, Ohio, Texas, and Wisconsin.
---------------------------------------------------------------------------

    \36\ See the following actions: Indiana (81 FR 38957, June 15, 
2016); Kentucky (78 FR 14681, March 7, 2013); Louisiana (81 FR 
53308, August 12, 2016); New York (81 FR 58849, August 26, 2016); 
Ohio (81 FR 38957, June 15, 2016); Texas (81 FR 53284, August 12, 
2016); and Wisconsin (81 FR 53309, August 12, 2016).
---------------------------------------------------------------------------

    As discussed in more detail in the next section, in issuing the 
CSAPR Update, the EPA did not determine that it had entirely addressed 
the EPA's outstanding CAA obligations to implement the good neighbor 
provision with respect to the 2008 ozone NAAQS for 21 of 22 states 
covered by that rule. Accordingly, the CSAPR Update did not fully 
satisfy the EPA's obligation to address the good neighbor provision 
requirements for those states by approving SIPs, issuing FIPs, or some 
combination of those two actions. The EPA found that the CSAPR Update 
FIP fully addressed the good neighbor provision for the 2008 ozone 
NAAQS only with respect to Tennessee.
    The EPA notes that it has also already separately proposed an 
action to fully address Kentucky's good neighbor obligation for the 
2008 ozone NAAQS. 83 FR 17123 (Apr. 18, 2018). On May 23, 2017, the 
U.S. District Court for the Northern District of California issued an 
order requiring the EPA to take a final action fully addressing the 
good neighbor obligation for the 2008 ozone NAAQS for Kentucky by June 
30, 2018. See Order, Sierra Club v. Pruitt, No. 3:15-cv-04328 (N.D. 
Cal. May 23, 2017). On February 28, 2018, Kentucky submitted to the EPA 
a draft SIP addressing the remaining good neighbor obligation. On May 
10, 2018, Kentucky submitted their final SIP to EPA. The EPA proposed 
to approve the state's draft SIP, 83 FR 17123 (April 18, 2018), and 
intends to take an appropriate final action that would address this 
obligation for Kentucky consistent with the court-ordered deadline.
    As noted previously, subsequent to the promulgation of the CSAPR 
Update, the EPA approved a SIP fully replacing the FIP for Alabama. 82 
FR 46674 (October 6, 2017). In that SIP approval, the EPA found that 
the rule partially satisfies Alabama's good neighbor obligation for the 
2008 ozone NAAQS. Thus, the EPA continues to have an obligation, 
stemming from the July 13, 2015 findings notice, to fully address the 
good neighbor provision requirements for the 2008 NAAQS with respect to 
Alabama. As previously

[[Page 31921]]

noted, other states have also submitted SIPs, some of which the EPA has 
approved and some of which still remain pending. However, these states 
are not the subject of this rulemaking and these actions are therefore 
not described in detail in this section.
    Table II.C-1 summarizes the statutory deadline for the EPA to 
address its FIP obligation under CAA section 110(c) and the event that 
activated the EPA's obligation for each of the 20 remaining CSAPR 
Update states addressed in this proposed action. For more information 
regarding the actions triggering the EPA's FIP obligation and the EPA's 
action on SIPs addressing the good neighbor provision for the 2008 
ozone NAAQS, see the memorandum, Status of 110(a)(2)(D)(i)(I) SIPs for 
the 2008 Ozone NAAQS, in the docket for this action.

 Table II.C-1--Events That Activated EPA's Obligation and Statutory FIP
                                Deadlines
------------------------------------------------------------------------
                                      Type of action
                                     (Federal Register    Statutory FIP
              State                      citation,        deadline \37\
                                     publication date)
------------------------------------------------------------------------
Alabama..........................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Arkansas.........................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Illinois.........................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Indiana..........................  SIP disapproval (81         7/15/2018
                                    FR 38957, 6/15/
                                    2016).
Iowa.............................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Kansas...........................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Louisiana........................  SIP disapproval (81         9/12/2018
                                    FR 53308, 8/12/
                                    2016).
Maryland.........................  Finding of Failure          8/19/2018
                                    to Submit (81 FR
                                    47040, 7/20/2016).
Michigan.........................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Mississippi......................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Missouri.........................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
New Jersey.......................  Finding of Failure          7/15/2018
                                    to Submit (81 FR
                                    38963, 6/15/2016).
New York.........................  SIP disapproval (81         9/26/2018
                                    FR 58849, 8/12/
                                    2016).
Ohio.............................  SIP disapproval (81         7/15/2018
                                    FR 38957, 6/15/
                                    2016).
Oklahoma.........................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Pennsylvania.....................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Texas............................  SIP disapproval (81         9/12/2018
                                    FR 53284, 8/12/
                                    2016).
Virginia.........................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
West Virginia....................  Finding of Failure          8/12/2017
                                    to Submit (80 FR
                                    39961, 7/13/2015).
Wisconsin........................  Partial SIP                 9/12/2018
                                    disapproval as to
                                    prong 2 (81 FR
                                    53309, 8/12/2016).
------------------------------------------------------------------------

D. Summary of the CSAPR Update
---------------------------------------------------------------------------

    \37\ The FIP deadline is two years from the effective date of 
the SIP disapproval or Finding of Failure to Submit, which generally 
trails the publication date by 30 or 45 days.
---------------------------------------------------------------------------

    On October 16, 2016, the EPA finalized the CSAPR Update. The 
purpose of the CSAPR Update was to protect public health and welfare by 
reducing interstate pollution transport that significantly contributes 
to nonattainment, or interferes with maintenance, of the 2008 ozone 
NAAQS in the eastern U.S. As discussed in section II.C, the EPA 
finalized a FIP for each of the 22 states subject to the rule,\38\ 
either having previously found that those states failed to submit a 
complete good neighbor SIP (15 states) or having issued a final rule 
disapproving their good neighbor SIP submittals (7 states). For the 22 
states covered by the CSAPR Update, the EPA promulgated EGU ozone 
season NOX emissions budgets, implemented through a regional 
allowance trading program, to reduce interstate ozone transport for the 
2008 ozone NAAQS during the ozone season (May-September), beginning 
with the 2017 ozone season.
---------------------------------------------------------------------------

    \38\ Alabama, Arkansas, Illinois, Indiana, Iowa, Kansas, 
Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, New 
Jersey, New York, Ohio, Oklahoma, Pennsylvania, Tennessee, Texas, 
Virginia, West Virginia, and Wisconsin.
---------------------------------------------------------------------------

    The EPA aligned its analysis for the CSAPR Update (and 
implementation of the trading program) with relevant attainment dates 
for the 2008 ozone NAAQS, consistent with the D.C. Circuit's decision 
in North Carolina v. EPA.\39\ The EPA's final 2008 Ozone NAAQS SIP 
Requirements Rule established the attainment deadline of July 20, 2018 
for ozone nonattainment areas classified as Moderate.\40\ Because the 
attainment date falls during the 2018 ozone season, the 2017 ozone 
season was the last full season from which data could be used to 
determine attainment of the NAAQS by the July 20, 2018 attainment date. 
Therefore, consistent with the court's instruction in North Carolina, 
the EPA established and implemented emissions budgets starting with the 
2017 ozone season. 81 FR 74507.
---------------------------------------------------------------------------

    \39\ 531 F.3d 896, 911-12 (D.C. Cir. 2008) (holding that the EPA 
must coordinate interstate transport compliance deadlines with 
downwind attainment deadlines).
    \40\ 80 FR 12264, 12268 (Mar. 6, 2015); 40 CFR 51.1103. Ozone 
nonattainment areas are classified as either Marginal, Moderate, 
Serious, Severe, or Extreme, based on the severity of the air 
quality problem in the area. Areas with more acute air quality 
problems are required to implement more stringent control 
requirements and are provided additional time to attain the NAAQS. 
See CAA sections 181 and 182, 42 U.S.C. 7511, 7511a.
---------------------------------------------------------------------------

    To establish the CSAPR Update emissions budgets, the EPA followed a 
four-step analytic process that has been used in each of the Agency's 
regional interstate transport rulemakings. The four-step interstate 
transport framework is described in more detail in section III.A. To 
summarize, in step 1, the Agency identified downwind receptors that are 
expected to have problems attaining or maintaining the NAAQS. In step 
2, the EPA examined which upwind states contribute to the nonattainment 
or maintenance receptors identified in step 1. In step 3, the EPA 
quantified the upwind emissions that significantly contribute to 
nonattainment or interfere with maintenance. The EPA quantified 
significantly contributing emissions from upwind states by evaluating 
levels of uniform NOX control stringency, represented by an 
estimated marginal cost per ton of NOX reduced. The EPA 
applied a multi-factor test to evaluate cost, available emissions 
reductions, and downwind air quality impacts to determine the 
appropriate level of uniform NOX control stringency that 
addressed the impacts of interstate transport on downwind nonattainment 
or maintenance receptors. The EPA used

[[Page 31922]]

this multi-factor assessment to gauge the extent to which emissions 
reductions should be implemented beginning in 2017 and to ensure those 
reductions do not represent over-control. In step 4, the EPA identified 
emissions budgets for significantly contributing states that reflected 
the absence of significant contribution and provided for implementation 
of the budgets through an allowance trading program.
    The multi-factor test generated a ``knee in the curve,'' i.e., a 
point at which the cost-effectiveness of the emissions reductions is 
maximized, so named for the discernable turning point observable in a 
cost curve. See 81 FR 74550. In the CSAPR Update this was at the point 
where emissions budgets reflected a control stringency with an 
estimated marginal cost of $1,400 per ton of NOX reduced. 
This level of stringency in emissions budgets represented the level at 
which incremental EGU NOX reduction potential and 
corresponding downwind ozone air quality improvements were maximized--
relative to other cost levels evaluated--with respect to marginal cost. 
That is, the ratio of emissions reductions to marginal cost and the 
ratio of ozone improvements to marginal cost were maximized relative to 
the other emissions budget levels evaluated. The EPA found that highly 
cost-effective EGU NOX reductions were available to make 
meaningful and timely improvements in downwind ozone air quality to 
address interstate ozone transport for the 2008 ozone NAAQS for the 
2017 ozone season. 81 FR 74508. Further, the agency's evaluation showed 
that emissions budgets reflecting the $1,400 per ton cost threshold did 
not over-control upwind states' emissions relative to either the 
downwind air quality problems to which they were linked or the 1 
percent contribution threshold in step 2 that triggered their further 
evaluation in step 3. Id. at 74551-52. As a result, the EPA finalized 
EGU ozone season NOX emissions budgets developed using 
uniform control stringency represented by $1,400 per ton.
    To implement the CSAPR Update's emissions reductions, the EPA 
promulgated FIPs requiring power plants in covered states to 
participate in the CSAPR NOX Ozone Season Group 2 allowance 
trading program starting in 2017.\41\ CSAPR's trading programs and the 
EPA's prior emissions trading programs (e.g., CAIR and the 
NOX Budget Trading Program) provide a proven implementation 
framework for achieving emissions reductions. In addition to providing 
environmental certainty (i.e., a cap on emissions), these programs also 
provide regulated sources with flexibility in choosing compliance 
strategies. By using the CSAPR allowance trading programs, the EPA 
applied an implementation framework that was shaped by notice and 
comment in previous rulemakings and reflected the evolution of these 
programs in response to court decisions and practical experience gained 
by states, industry, and the EPA.
---------------------------------------------------------------------------

    \41\ The ozone season NOX allowance trading program 
created under the original CSAPR was renamed the CSAPR 
NOX Ozone Season Group 1 Trading Program and now applies 
only to sources in Georgia. In the CSAPR Update, the EPA found that 
Georgia did not contribute to interstate transport with respect to 
the 2008 ozone NAAQS, but the state has an ongoing ozone season 
NOX requirement under the original CSAPR.
---------------------------------------------------------------------------

    Based on information available at the time of its promulgation, the 
EPA was unable to conclude that the CSAPR Update fully addressed most 
of the covered states' good neighbor obligations for the 2008 ozone 
NAAQS. 81 FR 74521. Information available at the time indicated that, 
even with CSAPR Update implementation, several downwind receptors were 
expected to continue having problems attaining and maintaining this 
NAAQS and that emissions from upwind states were expected to continue 
to contribute greater than or equal to 1 percent of the NAAQS to these 
areas during the 2017 ozone season. Id. at 74551-52. Further, the EPA 
could not conclude at that time whether additional EGU and non-EGU 
reductions implemented on a longer timeframe than 2017 would be 
feasible and cost-effective to address states' good neighbor 
obligations for this NAAQS.
    As noted, the EPA premised its conclusion that the CSAPR Update may 
not fully address states' good neighbor obligations in part on the 
Agency's assessment that air quality problems would persist at downwind 
receptors in 2017 even with CSAPR Update implementation. The EPA's 
assessment of CSAPR Update implementation using the Air Quality 
Assessment Tool (AQAT) indicated that certain eastern air quality 
monitors would continue to have problems attaining and maintaining the 
2008 ozone NAAQS in 2017. 81 FR 74550-52. Specifically, projected 
nonattainment receptors remained in Connecticut, Texas, and Wisconsin, 
while projected maintenance-only receptors remained in Connecticut, 
Maryland, Michigan, New York, and Texas.\42\ See Table II.C-1 for a 
list of remaining nonattainment receptors and Table II.C-2 for a list 
of remaining maintenance-only receptors. (The EPA's approach to 
defining nonattainment and maintenance-only receptors is explained in 
section III.C.1 below.)
---------------------------------------------------------------------------

    \42\ Projected AQAT design values for the $1400/ton policy case 
are available in Tables D-6 and D-7 of the CSAPR Update ``Ozone 
Transport Policy Analysis Final Rule TSD'' (August 2016), Docket ID 
No. EPA-HQ-OAR-2015-0500-0555.

  Table II.C-2--Remaining 2017 Projected Nonattainment Receptors in the
                              Eastern U.S.
------------------------------------------------------------------------
      Monitor ID                 State                    County
------------------------------------------------------------------------
090019003.............  Connecticut............  Fairfield.
090099002.............  Connecticut............  New Haven.
480391004.............  Texas..................  Brazoria.
484392003.............  Texas..................  Tarrant.
484393009.............  Texas..................  Tarrant.
551170006.............  Wisconsin..............  Sheboygan.
------------------------------------------------------------------------


Table II.C-3--Remaining 2017 Projected Maintenance-Only Receptors in the
                              Eastern U.S.
------------------------------------------------------------------------
      Monitor ID                 State                    County
------------------------------------------------------------------------
090010017.............  Connecticut............  Fairfield.
090013007.............  Connecticut............  Fairfield.
240251001.............  Maryland...............  Harford.
260050003.............  Michigan...............  Allegan.
360850067.............  New York...............  Richmond.
361030002.............  New York...............  Suffolk.
481210034.............  Texas..................  Denton.
482010024.............  Texas..................  Harris.
482011034.............  Texas..................  Harris.
482011039.............  Texas..................  Harris.
------------------------------------------------------------------------

    The EPA's analysis also showed that 21 of the 22 CSAPR Update 
states would continue to contribute equal to or greater than 1 percent 
of the 2008 ozone NAAQS to at least one remaining nonattainment or 
maintenance receptor in 2017.\43\ Thus, for those 21 states, the EPA 
could not, based on information available in the CSAPR Update 
rulemaking, make an air quality-based conclusion that the CSAPR Update 
would fully resolve states' good neighbor obligations with respect to 
the 2008 ozone NAAQS. (For one state, Tennessee, the EPA determined 
that the CSAPR Update fully resolved its good neighbor obligation.)
---------------------------------------------------------------------------

    \43\ See EPA's Air Quality Assessment Tool from the CSAPR Update 
in the docket for this rulemaking.
---------------------------------------------------------------------------

    Further, it was not feasible for the EPA to complete an emissions 
control analysis that would otherwise be necessary to evaluate full 
elimination of each state's significant contribution to nonattainment 
or interference with maintenance and also ensure that emissions 
reductions would be achieved by 2017. 81 FR at 74522. Specifically, the 
EPA was unable to fully consider both non-EGU ozone season 
NOX

[[Page 31923]]

reductions and further EGU reductions that may have been achievable 
after 2017. Id. at 74521. The EPA did not quantify non-EGU stationary 
source emissions reductions to address interstate ozone transport for 
the 2008 ozone NAAQS in the CSAPR Update for two reasons. First, the 
EPA explained that there was greater uncertainty in the EPA's 
assessment of non-EGU NOX mitigation potential, and that 
more time would be required for states and the EPA to improve non-EGU 
point source data and pollution control assumptions before we could 
develop emissions reduction obligations based on that data. Id. at 
74542. Second, the EPA explained that we did not believe that 
significant, certain, and meaningful non-EGU NOX reductions 
were feasible for the 2017 ozone season. Id. Many commenters generally 
agreed with the EPA that non-EGU emissions reductions were not readily 
available for the 2017 ozone season but some advocated that such 
reductions should be included as appropriate in future mitigation 
actions. Id. at 74521-22. With respect to EGUs, the EPA concluded that 
additional control strategies, such as the implementation of new post-
combustion controls, would take several years to implement, which was 
beyond the 2017 ozone season targeted in the CSAPR Update. Id. at 
74541. Thus, the EPA could not make an emissions reduction-based 
conclusion that the CSAPR Update would fully resolve states' good 
neighbor obligations with respect to the 2008 ozone NAAQS because the 
reductions required by the CSAPR Update were EGU-only and because the 
EPA focused the policy analysis for the CSAPR Update on reductions 
available by the beginning of the 2017 ozone season.
    Finally, in promulgating the CSAPR Update, the EPA stated its 
belief that it was beneficial to implement, without further delay, EGU 
NOX reductions that were achievable in the near term, 
particularly before the Moderate area attainment date of 2018. 
Notwithstanding that additional reductions may be required to fully 
address the states' interstate transport obligations, the EGU 
NOX emissions reductions implemented by the final rule were 
needed for upwind states to eliminate their significant contribution to 
nonattainment or interference with maintenance of the 2008 ozone NAAQS 
and to assist downwind states with ozone nonattainment areas that are 
required to attain the standard by July 20, 2018.
    As a result of the remaining air quality problems and the 
limitations on the EPA's analysis, for all but one of the 21 states at 
issue, the EPA did not determine in the CSAPR Update that the CSAPR 
Update fully addressed those states' downwind air quality impacts under 
the good neighbor provision for the 2008 ozone NAAQS. Id. at 74521. For 
one state, Tennessee, the EPA determined in the final CSAPR Update that 
Tennessee's emissions budget fully eliminated the state's significant 
contribution to downwind nonattainment and interference with 
maintenance of the 2008 ozone NAAQS because the downwind air quality 
problems to which the state was linked were projected to be resolved 
with implementation of the CSAPR Update. Id. at 74552.

III. Proposed Determination Regarding Good Neighbor Obligations for the 
2008 Ozone NAAQS

    As described in section II.D, in the CSAPR Update the EPA 
promulgated FIPs intended to address the good neighbor provision for 
the 2008 ozone NAAQS, but could not at that time determine that those 
FIPs fully address 2008 ozone NAAQS good neighbor obligations for 21 of 
the 22 CSAPR Update states, based on information available when the 
rule was finalized. As a result, the CSAPR Update did not fully satisfy 
the EPA's obligation to issue FIPs or approve SIPs to address those 
states' good neighbor obligations for the 2008 ozone NAAQS. In this 
notice, the EPA proposes to determine that, based on additional 
information and analysis, the CSAPR Update fully addresses 20 of these 
states' good neighbor obligations for the 2008 ozone NAAQS. In 
particular, the EPA proposes to determine that there will be no 
remaining nonattainment or maintenance receptors in the eastern U.S. in 
2023. Therefore, after the CSAPR Update is implemented, these states 
are not expected to contribute significantly to nonattainment in, or 
interfere with maintenance by, any other state with regard to the 2008 
ozone NAAQS. The obligation as to the remaining state (Kentucky) is 
currently being addressed in a separate action.

A. Analytic Approach

    The Agency is evaluating its determination regarding CSAPR Update 
states' remaining good neighbor obligations for the 2008 ozone NAAQS by 
applying the same approach used in previous federal actions addressing 
regional interstate transport of ozone pollution, including the CSAPR 
Update which addressed the same NAAQS at issue in this rulemaking. Each 
of these rulemakings followed the same four-step interstate transport 
framework to quantify and implement emissions reductions necessary to 
address the interstate transport requirements of the good neighbor 
provision.\44\ These steps are summarized in the following four 
paragraphs.
---------------------------------------------------------------------------

    \44\ With respect to the 2015 ozone NAAQS, the EPA recently 
provided information to states to inform their development of SIPs 
to address CAA section 110(a)(2)(D)(i)(I). In a memorandum dated 
March 27, 2018, the Agency noted that, in developing their own 
rules, states have flexibility to follow the familiar 4-step 
transport framework (using the EPA's analytical approach or somewhat 
different analytical approaches within these steps) or alternative 
frameworks, so long as their chosen approach has adequate technical 
justification and is consistent with the requirements of the CAA.
---------------------------------------------------------------------------

    Step 1: Identify downwind air quality problems relative to the 2008 
ozone NAAQS. The EPA has historically identified downwind receptors 
with air quality problems using air quality modeling projections and, 
where appropriate, considering monitored ozone data for a future 
compliance year. In the CSAPR Update, the agency relied on modeled and 
monitored data to identify not only those receptors expected to be in 
nonattainment with the ozone NAAQS, but also those receptors that may 
have difficulty maintaining the NAAQS, notwithstanding clean monitored 
data or projected attainment.
    Step 2: Determine which upwind states are ``linked'' to these 
identified downwind air quality problems and thereby warrant further 
analysis to determine whether their emissions violate the good neighbor 
provision. In the CSAPR Update, the EPA identified such upwind states 
as those modeled to contribute to a downwind receptor at or above an 
air quality threshold equivalent to one percent of the 2008 ozone 
NAAQS.
    Step 3: For states linked to downwind air quality problems, 
identify upwind emissions on a statewide basis that significantly 
contribute to nonattainment or interfere with maintenance of a standard 
in any area. In all of the EPA's prior rulemakings addressing 
interstate ozone pollution transport, the Agency identified and 
apportioned emissions reduction responsibility among multiple upwind 
states linked to downwind air quality problems by considering feasible 
NOX control strategies and using cost-based and air quality-
based criteria to evaluate regionally uniform NOX control 
strategies that were then used to quantify the amount of a linked 
upwind state's emissions, if any, that significantly contribute to 
nonattainment or interfere with maintenance in another state.

[[Page 31924]]

    Step 4: For upwind states that are found to have emissions that 
significantly contribute to nonattainment or interfere with maintenance 
of the NAAQS downwind, implement the necessary emissions reductions 
within the state. In the CSAPR Update, the EPA implemented the 
necessary emissions reductions from upwind states found to have good 
neighbor obligations by requiring EGUs in those states to participate 
in the CSAPR NOX Ozone Season Group 2 Trading Program, which 
is very similar to the allowance trading programs used to implement the 
emissions reductions quantified in the original CSAPR and other earlier 
rules.\45\
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    \45\ Affected sources have participated in EPA-administered 
allowance trading programs under both SIPs and FIPs.
---------------------------------------------------------------------------

    Because this action is evaluating outstanding obligations that 
remain with respect to the 2008 ozone NAAQS, the EPA believes it is 
reasonable to apply the same framework used in the CSAPR Update in this 
proposed action.
    Within this four-step interstate transport framework, the EPA only 
proceeds to step four, in which it requires sources in upwind states to 
implement enforceable emissions limitations, if: (1) Downwind air 
quality problems are identified in at step 1; (2) an upwind state is 
linked to a downwind air quality problem at step 2; and (3) sources in 
the linked upwind state are identified as having emissions that 
significantly contribute to nonattainment and interfere with 
maintenance of the NAAQS considering cost- and air-quality-based 
factors. For the reasons described in the following paragraphs, the EPA 
believes this approach is a reasonable interpretation of the good 
neighbor provision.
    The good neighbor provision instructs the EPA and states to apply 
its requirements ``consistent with the provisions of'' title I of the 
CAA. The EPA is therefore interpreting the requirements of the good 
neighbor provision, and the elements of its four-step interstate 
transport framework, to apply in a manner consistent with the 
designation and planning requirements in title I that apply in downwind 
states. See North Carolina, 531 F.3d at 912 (holding that the good 
neighbor provision's reference to title I requires consideration of 
both procedural and substantive provisions in title I). The EPA notes 
that this consistency instruction follows the requirement that plans 
``contain adequate provisions prohibiting'' certain emissions in the 
good neighbor provision. The following paragraphs will therefore 
explain how the EPA's interpretation of the circumstances under which 
the good neighbor provision requires that plans ``prohibit'' emissions 
through enforceable measures is consistent with the circumstances under 
which downwind states are required to implement emissions control 
measures in nonattainment areas.
    For purposes of this analysis, the EPA notes specific aspects of 
the title I designations process and attainment planning requirements 
for the ozone NAAQS that provide particularly relevant context for 
evaluating the consistency of the EPA's approach to the good neighbor 
provision in upwind states. The EPA notes that this discussion is not 
intended to suggest that the specific requirements of designations and 
attainment planning apply to upwind states pursuant to the good 
neighbor provision, but rather to explain why the EPA's approach to 
interpreting the good neighbor approach is reasonable in light of 
relevant, comparable provisions found elsewhere in title I. In 
particular, these provisions demonstrate that the EPA's approach is 
consistent with other relevant provisions of title I with respect to 
what data is considered in the EPA's analysis and when states are 
required to implement enforceable measures.
    First, areas are initially designated attainment or nonattainment 
for the ozone NAAQS based on actual measured ozone concentrations. CAA 
section 107(d) (noting that an area shall be designated attainment 
where it ``meets'' the NAAQS and nonattainment where it ``does not 
meet'' the NAAQS). Therefore, a designation of nonattainment does not 
in the first instance depend on what specific factors have influenced 
the measured ozone concentrations or whether such levels are due to 
enforceable emissions limits. If an area measures a violation of the 
relevant ozone NAAQS, then the area is designated nonattainment. In 
cases where the ozone nonattainment area is classified as Moderate or 
higher, the responsible state is required to develop an attainment 
plan, which generally includes the application of various enforceable 
control measures to sources of emissions located in the nonattainment 
area, consistent with the requirements in Part D of title I of the 
Act.\46\ See generally CAA section 182, 42 U.S.C. 7511a. If, however, 
an area measures compliance with the ozone NAAQS, the area is 
designated attainment, and sources in that area generally are not 
subject to any new enforceable control measures under Part D.\47\
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    \46\ Areas classified as Marginal nonattainment areas are 
required to submit emissions inventories and implement a 
nonattainment new source review permitting program, but are not 
generally required to implement controls at existing sources. See 
CAA section 182(a), 42 U.S.C. 7511a(a).
    \47\ Clean Air Act section 184 contains the exception to this 
general rule: states that are part of the Ozone Transport Region are 
required to provide SIPs that include specific enforceable control 
measures, similar to those for nonattainment areas, that apply to 
the whole state, even for areas designated attainment for the ozone 
NAAQS. See generally 42 U.S.C. 7511c.
---------------------------------------------------------------------------

    Similarly, in determining the boundaries of an ozone nonattainment 
area, the CAA requires the EPA to consider whether ``nearby'' areas 
``contribute'' to ambient air quality in the area that does not meet 
the NAAQS. 42 U.S.C. 7407(d). For each monitor or group of monitors 
indicating a violation of the ozone NAAQS, the EPA assesses information 
related to five factors, including current emissions and emissions-
related data from the areas near the monitor(s), for the purpose of 
establishing the appropriate geographic boundaries for the designated 
ozone nonattainment areas. A nearby area may be included within the 
boundary of the ozone nonattainment area only after assessing area-
specific information, including an assessment of whether current 
emissions from that area contribute to the air quality problem 
identified at the violating monitor.\48\ If such a determination is 
made, sources in the nearby area are also subject to the applicable 
Part D control requirements. However, if the EPA determines that the 
nearby area does not contribute to the measured nonattainment problem, 
then the nearby area is not part of the designated nonattainment area 
and sources in that area are not subject to such nonattainment control 
requirements.
---------------------------------------------------------------------------

    \48\ See Attachment 2 to Area Designations for the 2008 Ozone 
National Ambient Air Quality Standards. Memorandum from Robert J. 
Meyers, Principal Deputy Assistant Administrator, US EPA to Regional 
Administrators. December 4, 2008. Available at https://archive.epa.gov/ozonedesignations/web/pdf/area_designations_for_the_2008_revised_ozone_naaqs.pdf.
---------------------------------------------------------------------------

    The EPA's historical approach to addressing the good neighbor 
provision via the four-step interstate transport framework, and the 
approach the EPA proposes to continue to apply here, is consistent with 
these title I requirements. That is, in steps 1 and 2 of the framework, 
the EPA evaluates whether there is a downwind air quality problem 
(either nonattainment or maintenance), and whether an upwind state 
impacts the downwind area such that it contributes to and is therefore 
``linked'' to the downwind area. The EPA's determination at step 1 of 
the good neighbor analysis that it has not

[[Page 31925]]

identified any downwind air quality problems to which an upwind state 
could contribute is analogous to the EPA's determination in the 
designation analysis that an area should be designated attainment. 
Similarly, EPA's determination at step 2 of the good neighbor analysis 
that, while it has at step 1 identified downwind air quality problems, 
an upwind state does not sufficiently impact the downwind area such 
that the state is ``linked,'' is analogous to the EPA's determination 
in the designation analysis that a nearby area does not contribute to a 
NAAQS violation in another area. Thus, under the good neighbor 
provision, the EPA determines at step 1 or 2, as appropriate, that the 
upwind state will not significantly contribute to nonattainment or 
interfere with maintenance in the downwind area. See, e.g., 81 FR 74506 
(determining that emissions from 14 states do not significantly 
contribute to nonattainment or interfere with maintenance of the 2008 
ozone NAAQS); 76 FR 48236 (finding that states whose contributions to 
downwind receptors are below the air quality threshold do not 
significantly contribute to nonattainment or interfere with maintenance 
of the relevant NAAQS). Under such circumstances, sources in the upwind 
state are not obligated to implement any control measures under the 
good neighbor provision, which is consistent with the fact that sources 
located in attainment areas generally are not required to implement the 
control measures found in Part D of the Act. Cf. EME Homer City II, 795 
F.3d at 130 (determining that CSAPR ozone-season NOX budgets 
for 10 states were invalid based on determination that modeling showed 
no future air quality problems); 81 FR 74523-24 (removing three states 
from CSAPR ozone season NOX program based on determination 
that states are not linked to any remaining air quality problems for 
the 1997 ozone NAAQS).
    The EPA acknowledges one distinction between the good neighbor and 
designation analyses: The good neighbor analysis relies on future-year 
projections of emissions to calculate ozone concentrations and upwind 
state contributions, compared to the designation analysis's use of 
current measured data. As described in more detail later, this approach 
is a reasonable interpretation of the term ``will'' in the good 
neighbor provision, see North Carolina, 531 F.3d at 913-14, and 
interpreting language specific to that provision does not create an 
impermissible inconsistency with other provisions of title I. Moreover, 
the EPA's use of future-year modeling in the good neighbor analysis to 
identify downwind air quality problems and linked states is consistent 
with its use of current measured data in the designations process. The 
EPA's future-year air quality projections consider a variety of 
factors, including current emissions data, anticipated future control 
measures, economic market influences, and meteorology. Many of these 
same factors, e.g., current control measures, economic market 
influences, and meteorology, can affect the NOX emissions 
levels and consequent measured ozone concentrations that inform the 
designations process. Like the factors that affect measured ozone 
concentrations used in the designations process, not all of the factors 
influencing the EPA's modeling projections are or can be enforceable 
limitations on emissions or ozone concentrations. However, the EPA 
believes that consideration of these factors contributes to a 
reasonable estimate of anticipated future ozone concentrations. See EME 
Homer City II, 795 F.3d at 135 (declining to invalidate EPA's modeling 
projections ``solely because there might be discrepancies between those 
predictions and the real world''); Chemical Manufacturers Association 
v. EPA, 28 F.3d 1259, 1264 (DC Cir. 1994) (``a model is meant to 
simplify reality in order to make it tractable''). Thus, the EPA 
believes that consideration of these factors in its future-year 
modeling projections used at steps 1 and 2 of the good neighbor 
analysis is reasonable and consistent with the use of measured data in 
the designation analysis.\49\
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    \49\ The EPA also notes that the consideration of projected 
actual emissions in the future analytic year--as opposed to 
allowable levels--is also consistent with the statute's instruction 
that states (or EPA in the states' stead) prohibit emissions that 
``will'' impermissibly impact downwind air quality. This term is 
reasonably interpreted to mean that the EPA should evaluate 
anticipated emissions (what sources will emit) rather than potential 
emissions (what sources could emit).
---------------------------------------------------------------------------

    The EPA notes that there is a further distinction between the 
section 107(d) designations provision and the good neighbor provision 
in that the latter provision uses different terms to describe the 
threshold for determining whether emissions in an upwind state should 
be regulated (``contribute significantly'') as compared to the standard 
for evaluating the impact of nearby areas in the designations process 
(``contribute''). Thus, at step 3 of the good neighbor analysis the EPA 
evaluates additional factors, including cost and air-quality 
considerations, to determine whether emissions from a linked upwind 
state do or would violate the good neighbor provision. Only if the EPA 
at step 3 determines that the upwind state's emissions do or would 
violate the good neighbor provision will it proceed to step 4, at which 
point emissions in the upwind state must be controlled so as to address 
the identified violation, analogous to the trigger for the application 
of Part D requirements to sources located in designated nonattainment 
areas. The EPA interprets the good neighbor provision to not require it 
or the upwind state to proceed to step 4 and implement any enforceable 
measures to ``prohibit'' emissions unless it identifies a violation of 
the provision at step 3. See, e.g., 76 FR 48262 (finding at step 3 that 
the District of Columbia is not violating the good neighbor provision, 
and therefore will not at step 4 be subject to any control requirements 
in CSAPR, because no cost-effective emissions reductions were 
identified).

B. Selection of a Future Analytic Year

    In this action, consistent with historical practice, the EPA 
focuses its analysis on a future year in light of the forward-looking 
nature of the good neighbor obligation in section 110(a)(2)(D)(i)(I). 
Specifically, the statute requires that states prohibit emissions that 
``will'' significantly contribute to nonattainment or interfere with 
maintenance of the NAAQS in any other state. The EPA reasonably 
interprets this language as permitting states and the EPA in 
implementing the good neighbor provision to prospectively evaluate 
downwind air quality problems and the need for further upwind emissions 
reductions. In the EPA's prior regional transport rulemakings, the 
Agency generally evaluated whether upwind states ``will'' significantly 
contribute to nonattainment or interfere with maintenance based on 
projections of air quality in the future year in which any emissions 
reductions would be expected to go into effect. Thus, when the EPA 
finalized the NOX SIP Call in 1998, it used the anticipated 
2007 full compliance year for its analysis, and when the EPA finalized 
CAIR in 2005, it used the years 2009 and 2010, anticipated compliance 
years for the 1997 ozone and 1997 PM2.5 NAAQS, respectively. 
63 FR 57377; 70 FR 25241. The D.C. Circuit affirmed the EPA's 
interpretation of ``will'' in CAIR, finding the EPA's consideration of 
future projected air quality (in addition to current measured data) to 
be a reasonable interpretation of an ambiguous term. North Carolina, 
531 F.3d at 913-14. The EPA applied the same approach in finalizing 
CSAPR in

[[Page 31926]]

2011 and the CSAPR Update in 2016 by evaluating air quality in 2012 and 
2017, respectively. 76 FR 48211; 81 FR 74537. Thus, consistent with 
this precedent, a key decision that informs the application of the 
interstate transport framework is selecting a future analytic year. In 
determining the appropriate future analytic year for purposes of 
assessing remaining interstate transport obligations for the 2008 ozone 
NAAQS, the EPA considered two primary factors: (1) The applicable 
attainment dates; and (2) the timing to feasibly implement new 
NOX control strategies, which are discussed in the following 
two sections. The EPA proposes to determine that these factors 
collectively support the use of 2023 as the future analytic year for 
this proposed action.
1. Attainment Dates for the 2008 Ozone NAAQS
    First, the EPA considers the downwind attainment dates for the 2008 
ozone NAAQS. In North Carolina, the D.C. Circuit held that emissions 
reductions required by the good neighbor provision should be evaluated 
considering the relevant attainment dates of downwind nonattainment 
areas impacted by interstate transport. 531 F.3d at 911-12 (holding 
that the EPA must consider downwind attainment dates when establishing 
interstate transport compliance deadlines). Many areas currently have 
attainment dates of July 20, 2018 for areas classified as Moderate, 
but, as noted earlier, the 2017 ozone season was the last full season 
from which data could be used to determine attainment of the NAAQS by 
the July 20, 2018 attainment date. Given that the 2017 ozone season has 
now passed, it is not possible to achieve additional emissions 
reductions by the Moderate area attainment date. It is therefore 
necessary to consider what subsequent attainment dates should inform 
the EPA's analysis. The next attainment dates for the 2008 ozone NAAQS 
will be July 20, 2021, for nonattainment areas classified as Serious, 
and July 20, 2027, for nonattainment areas classified as Severe.\50\ 
Because the various attainment deadlines are in July, which is in the 
middle of the ozone monitoring season for all states, data from the 
calendar year prior to the attainment date (e.g., data from 2020 for 
the 2021 attainment date and from 2026 for the 2027 attainment date) 
are the last data that can be used to demonstrate attainment with the 
NAAQS by the relevant attainment date. Therefore, the EPA considers the 
control strategies that could be implemented by 2020 and 2026 in 
assessing the 2021 and 2027 attainment dates in its subsequent 
analysis. The EPA has also considered that, in all cases, the statute 
provides that areas should attain as expeditiously as practicable.\51\
---------------------------------------------------------------------------

    \50\ While there are no areas (outside of California) that are 
currently designated as Serious or Severe for the 2008 ozone NAAQS, 
the CAA requires that the EPA reclassify to Serious any Moderate 
nonattainment areas that fail to attain by their attainment date of 
July 20, 2018. Similarly, if any area fails to attain by the Serious 
area attainment date, the CAA requires that the EPA reclassify the 
area to Severe.
    \51\ See CAA section 181(a)(1), 42 U.S.C. 7511(a)(1).
---------------------------------------------------------------------------

2. Feasibility of Control Strategies To Reduce Ozone Season 
NOX
    Second, the EPA considers the timeframes that may be required to 
implement further emissions reductions as expeditiously as practicable. 
Generally, NOX emissions levels are expected to decline in 
the future through the combination of the implementation of existing 
local, state, and federal emissions reduction programs and changing 
market conditions for generation technologies and fuels.\52\ This is an 
important consideration because the U.S. Supreme Court and the D.C. 
Circuit Court have both held that the EPA may not over-control: It may 
not require emissions reductions (at step 3 of the good neighbor 
framework) from a state that are greater than necessary to achieve 
attainment and maintenance of the NAAQS in all of the downwind areas to 
which that state is linked.\53\ In particular, in EME Homer City II, 
the D.C. Circuit determined that the CSAPR phase 2 ozone-season 
NOX budgets for ten states were invalid because EPA's 
modeling showed that the downwind air quality problems to which these 
states were linked would be resolved by 2014, when the phase 2 budgets 
were scheduled to be implemented. 795 F.3d at 129-30. Therefore, 
because new controls cannot be implemented feasibly for several years, 
and at that later point in time air quality will likely be better due 
to continued phase-in of existing regulatory programs, changing market 
conditions, and fleet turnover, it is reasonable for the EPA to 
evaluate air quality (at step 1 of the good neighbor framework) in a 
future year that is aligned with feasible control installation timing 
in order to ensure that the upwind states continue (at step 2) to be 
linked to downwind air quality problems when any potential emissions 
reductions (identified at step 3) would be implemented (at step 4) and 
to ensure that such reductions do not over-control relative to the 
identified ozone problem.
---------------------------------------------------------------------------

    \52\ Annual Energy Outlook 2018. Electricity Supply, 
Disposition, Prices, and Emissions. Reference Case. Department of 
Energy, Energy Information Administration. Available at https://www.eia.gov/outlooks/aeo/data/browser/#/?id=8-AEO2018&cases=ref2018&sourcekey=0.
    \53\ EPA v. EME Homer City Generation, L.P., 134 S. Ct. at 1600-
01; EME Homer City II, 795 F.3d at 127.
---------------------------------------------------------------------------

    The EPA's analysis of the feasibility of NOX control 
strategies reflects the time needed to plan for, install, test, and 
place into operation new EGU and non-EGU NOX reduction 
strategies regionally--i.e., across multiple states. This regional 
analytic approach is consistent with the regional nature of interstate 
ozone pollution transport as described in section II.A. The Agency 
adopted this approach for this proposal based on previous interstate 
ozone transport analyses showing that where eastern downwind ozone 
problems are identified, multiple upwind states typically are linked to 
these problems.\54\ Specifically of relevance to this action, as 
discussed in section II.C, the EPA's assessment of CSAPR Update 
implementation found that 21 states continued to contribute greater 
than or equal to 1% of the 2008 ozone NAAQS to identified downwind 
nonattainment or maintenance receptors in multiple downwind states in 
2017. Thus, to reasonably address these ozone transport problems, the 
EPA must identify and apportion emissions reduction responsibility 
across multiple upwind states. In other words, the EPA's analysis 
should necessarily be regional, rather than focused on individual 
linkages. Where such an analysis is needed for multiple states, the 
inquiry into the availability and feasibility of control options is 
necessarily considerably more complicated than for a single state or 
sector.
---------------------------------------------------------------------------

    \54\ 81 FR 74538.
---------------------------------------------------------------------------

    Further, the feasibility of new emissions controls should be 
considered with regard to multiple upwind source categories to ensure 
that the Agency properly evaluates NOX reduction potential 
and cost-effectiveness from all reasonable control measures (including 
those that are or may be available outside of the EGU sector). 
NOX emissions come from multiple anthropogenic source 
categories, such as mobile sources, electric utilities, resource 
extraction industries, and industrial and commercial facilities. As 
noted in section II.A, the EPA has historically addressed mobile source 
emissions through national rulemakings. Moreover, mobile source 
emissions are already decreasing

[[Page 31927]]

because of sector[hyphen]specific standards related to fuels, vehicle 
fuel economy, pollution controls, and repair and replacement of the 
existing fleet. Programs such as the Tier 3 vehicle emissions standards 
are already being phased in between now and 2023. That rule was 
finalized in 2014 with a phase-in schedule of 2017-2025 reflecting 
fleet turnover. Thus, another reason that in this proposed action the 
EPA has focused on stationary sources is that emissions reductions from 
those sources could likely be implemented more quickly than would 
result from any attempt to effect additional reductions from mobile 
sources beyond those described.
    Among stationary sources, EGUs in the eastern U.S. have been the 
primary subject of regulation to address interstate ozone pollution 
transport and have made significant financial investments to achieve 
emissions reductions. While the EPA continues to evaluate control 
feasibility for EGUs in its analysis, the EPA's recent analyses 
indicate that non-EGU source categories, which the EPA has not made 
subject to new regulations to address interstate ozone transport since 
the NOX SIP Call, may also be well-positioned to cost-
effectively reduce NOX relative to EGUs.\55\ Accordingly, 
the EPA's assessment of control feasibility focuses on both EGU and 
non-EGU sources.
---------------------------------------------------------------------------

    \55\ See Assessment of Non-EGU NOX Emission Controls, 
Cost of Controls, and Time for Compliance Final TSD from the CSAPR 
Update in the docket for this rulemaking.
---------------------------------------------------------------------------

a. EGUs
    First, the EPA presents its feasibility assessment of 
NOX control strategies for EGUs. In establishing the CSAPR 
Update EGU ozone season NOX emissions budgets, the Agency 
quantified the emissions reductions achievable from all NOX 
control strategies that were feasible to implement in less than one 
year and cost-effective at a marginal cost of $1,400 per ton of 
NOX removed.\56\ These EGU NOX control strategies 
were: optimizing NOX removal by existing, operational 
selective catalytic reduction (SCR) controls; turning on and optimizing 
existing idled SCR controls; installing state-of-the-art NOX 
combustion controls; and shifting generation to existing units with 
lower-NOX emissions rates within the same state. 81 FR 
74541. The Agency believes that the resulting CSAPR Update emissions 
budgets are being appropriately implemented under the CSAPR 
NOX Ozone Season Group 2 allowance trading program. 
Preliminary data for the 2017 ozone season (the first CSAPR Update 
compliance period) indicate that power plant ozone season 
NOX emissions across the 22 state CSAPR Update region were 
reduced by 77,420 tons (or 21%) from 2016 to 2017.\57\ As a result, 
total 2017 ozone season NOX emissions from covered EGUs 
across the 22 CSAPR Update states were approximately 294,478 tons,\58\ 
well below the sum of states' emissions budgets established in the 
CSAPR Update of 316,464 tons. Accordingly, for the purposes of this 
proposed determination, the EPA considers the turning on and optimizing 
of existing SCR controls and the installation of combustion controls to 
be NOX control strategies that have already been 
appropriately evaluated and implemented in the final CSAPR Update.
---------------------------------------------------------------------------

    \56\ The CSAPR Update was signed on September 7, 2016--
approximately 8 months before the beginning of the 2017 ozone season 
on May 1.
    \57\ https://ampd.epa.gov/ampd/ (Data current as of March 1, 
2018).
    \58\ Id.
---------------------------------------------------------------------------

    In the CSAPR Update, the EPA also identified one EGU NOX 
control strategy that was considered feasible to implement within one 
year but was not cost-effective at a marginal cost of $1,400 per ton of 
NOX removed: specifically, turning on existing idled 
selective non-catalytic reduction (SNCR) controls. In the CSAPR Update, 
the EPA identified a marginal cost of $3,400 per ton as the level of 
uniform control stringency that represents turning on and fully 
operating idled SNCR controls.\59\ However, the CSAPR Update finalized 
emissions budgets using $1,400 per ton control stringency, finding that 
this level of stringency represented the control level at which 
incremental EGU NOX reductions and corresponding downwind 
ozone air quality improvements were maximized with respect to marginal 
cost. In finding that use of the $1,400 control cost level was 
appropriate, the EPA established that the more stringent emissions 
budget level reflecting $3,400 per ton (representing turning on idled 
SNCR controls) yielded fewer additional emissions reductions and fewer 
air quality improvements relative to the increase in control costs. In 
other words, based on the CSAPR Update analysis, establishing emissions 
budgets at $3,400 per ton, and therefore developing budgets based on 
operation of idled SNCR controls, was not determined to be cost-
effective for addressing good neighbor provision obligations for the 
2008 ozone NAAQS. 81 FR 74550. The EPA believes that the strategy of 
turning on and fully operating idled SNCR controls was appropriately 
evaluated in the CSAPR Update with respect to addressing interstate 
ozone pollution transport for the 2008 ozone NAAQS. Accordingly, in 
this proposal the EPA is not further assessing this control strategy 
for purposes of identifying an appropriate future analytic year.
---------------------------------------------------------------------------

    \59\ See EGU NOX Mitigation Strategies Final Rule TSD 
(docket ID EPA-HQ-OAR-2015-0500-0554, available at 
www.regulations.gov and https://www.epa.gov/sites/production/files/2017-05/documents/egu_nox_mitigation_strategies_final_rule_tsd.pdf) 
(NOX Mitigation Strategies TSD).
---------------------------------------------------------------------------

    As mentioned previously, the EPA evaluated shifting generation from 
EGUs with higher NOX-emissions rates to EGUs with lower 
NOX-emissions rates as a means of reducing emissions in the 
context of the CSAPR Update. Shifting generation is a NOX 
control strategy that occurs on a time- and cost-continuum, in contrast 
to the relatively discrete price-points and installation timeframes 
that can be identified for combustion and post-combustion controls. 
Therefore, in the CSAPR Update, the EPA identified the discrete cost 
thresholds used to evaluate upwind states' good neighbor obligations 
based on its evaluation of combustion and post-combustion controls, and 
secondarily examined the amount of generation shifting that would 
result at the same cost threshold associated with the particular 
control technology. Quantifying NOX reductions from shifting 
generation anticipated at the same cost thresholds relative to the 
control technologies being considered (e.g., restarting idled SCR 
controls) helped ensure that the emissions reductions associated with 
the control strategies could be expected to occur. In other words, had 
the agency excluded consideration of generation shifting in calculating 
emissions budgets, generation shifting would have nonetheless occurred 
as a compliance strategy, but the consequence would have been a smaller 
amount of emissions reduction than what the agency knew to be 
achievable and cost[hyphen]effective at the selected cost threshold. 
Thus, although potential emissions reductions resulting from generation 
shifting were factored into the final budgets, this compliance strategy 
did not drive the EPA's identification of cost thresholds analyzed in 
the rule.
    For the same reasons, the EPA does not find it appropriate to 
evaluate generation shifting, in isolation from viable combustion or 
post-combustion control assessments, for purposes of selecting a future 
analytic year. If the EPA were to choose an earlier analytic year based 
on the ability of upwind sources to implement some level of

[[Page 31928]]

generation shifting within that timeframe, before other specific 
control technologies could be implemented, this would have the 
consequence of limiting the EPA's analysis and the amount of emissions 
reductions that would be considered cost-effective and therefore 
subject to regulation under the good neighbor provision, relative to a 
more robust analysis that considers other emissions controls available 
within defined timeframes. Further, due to continued lower cost natural 
gas prices and price projections, significant shifting from higher 
emitting coal sources to lower emitting gas sources (relative to 
historical generation levels) is occurring and expected to continue to 
occur by 2023 due to market drivers. Thus, there may be limited 
opportunity for the sources to implement further emissions reductions 
through generation shifting over the next 5 years. Given the 
indeterminate implementation timeframes for generation shifting and the 
EPA's historical consideration of this strategy as a secondary factor 
in quantifying emissions budgets, the EPA believes the most reasonable 
approach for selecting a future analytic year is to focus on the 
timeframe in which specific control technologies other than generation 
shifting can be implemented.\60\
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    \60\ Because the EPA is not in this proposal evaluating 
additional generation shifting possibilities, it does not at this 
time need to revisit the question whether it is within the EPA's 
authority or otherwise proper to consider generation shifting in 
implementing the good neighbor provision. The EPA is aware that this 
has been an issue of contention in the past, and stakeholders have 
raised serious concerns regarding this issue. See, e.g., 81 FR at 
74545 (responding to comments); CSAPR Update Rule--Response to 
Comment, at 534-50 (EPA-HQ-OAR-2015-0500-0572) (summarizing and 
responding to comments). The EPA may revisit this question in 
addressing good neighbor requirements for other NAAQS but is not 
soliciting comment at this time on this issue with regard to the 
2008 ozone NAAQS.
---------------------------------------------------------------------------

    For these reasons, for purposes of identifying an appropriate 
future analytic year, the EPA is focusing its assessment of EGUs in 
this action on controls that were deemed to be infeasible to install 
for the 2017 ozone season rather than reassessing controls previously 
analyzed for cost-effective emissions reductions in the CSAPR Update. 
In establishing the CSAPR Update emissions budgets, the EPA identified 
but did not analyze the following two EGU NOX control 
strategies in establishing the CSAPR Update emissions budgets because 
implementation by 2017 was not considered feasible: (1) Installing new 
SCR controls; and (2) installing new SNCR controls. In the CSAPR 
Update, EPA observed that EGU SCR post-combustion controls can achieve 
up to 90 percent reduction in EGU NOX emissions. In 2017, 
these controls were in widespread use by EGUs in the east. EPA also 
observed that SNCR controls can be effective at reducing NOX 
emissions and can achieve up to a 25 percent emissions reduction from 
EGUs (with sufficient reagent). In 2017, these controls were also used 
across the power sector. In the 22-state CSAPR Update region, 
approximately 62 percent of coal-fired EGU capacity is equipped with 
SCR controls and 12 percent is equipped with SNCR controls.\61\
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    \61\ National Electric Energy Data System v6 (NEEDS). EPA. 
Available at https://www.epa.gov/airmarkets/national-electric-energy-data-system-needs-v6.
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    Installing new SCR or SNCR controls for EGUs generally involves the 
following steps: conducting an engineering review of the facility; 
advertising and awarding a procurement contract; obtaining a 
construction permit; installing the control technology; testing the 
control technology; and obtaining or modifying an operating permit.\62\ 
Because installing these post-combustion controls--SCR or SNCR--involve 
the same steps and many of the same considerations, the timing of their 
feasible regional development is described together in the following 
paragraphs. However, the EPA notes differences between these control 
technologies with respect to the potential viability of achieving cost-
effective regional NOX reductions from EGUs. As described 
above, SCR controls generally achieve greater EGU NOX 
reduction efficiency (up to 90%) than SNCR controls (up to 25%). 
Resulting in part from this disparity in NOX reduction 
efficiency, when considering both control costs and NOX 
reduction potential in developing cost per ton analysis for the CSAPR 
Update, the EPA found new SCR controls to be more cost-effective at 
removing NOX. Specifically, the EPA found that new SCR 
controls could generally reduce EGU emissions for $5,000 per ton of 
NOX removed whereas new SNCR controls could generally reduce 
EGU emissions at a higher cost of $6,400 per ton of NOX 
removed.\63\ In other words, the greater NOX reduction 
efficiency for SCR controls translates into greater cost-effectiveness 
relative to SNCR controls. The general cost-effectiveness advantage is 
consistent with observed installation patterns where SCR controls (62% 
of coal-fired capacity) are more prevalent across the east relative to 
SNCR (12% of coal-fired capacity).
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    \62\ Final Report: Engineering and Economic Factors Affecting 
the Installation of Control Technologies for Multipollutant 
Strategies, EPA-600/R-02/073 (Oct. 2002), available at https://nepis.epa.gov/Adobe/PDF/P1001G0O.pdf.
    \63\ NOX Mitigation Strategies TSD.
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    For SCR, the total time associated with navigating necessary steps 
is estimated to be up to 39 months for an individual power plant 
installing SCR on more than one boiler.\64\ However, more time is 
needed when considering installation timing for new SCR controls across 
the Eastern EGU fleet addressed in this action. As described in the 
subsequent paragraphs, EPA determined that a minimum of 48 months is a 
reasonable time period to allow for the coordination of outages, 
shepherding of labor and material supply, and identification of 
retrofit projects. This timeframe would facilitate multiple power 
plants with multiple boilers to conduct all stages of post-combustion 
and combustion control project planning, installation, and operation.
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    \64\ Engineering and Economic Factors Affecting the Installation 
of Control Technologies for Multipollutant Strategies. EPA Final 
Report. Table 3-1. Available at https://archive.epa.gov/clearskies/web/pdf/multi102902.pdf.
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    Scheduled curtailment, or planned outage, for pollution control 
installation would be necessary to complete either SCR or SNCR 
projects. Given that peak demand and rule compliance would both fall in 
the ozone season, sources would likely try to schedule installation 
projects for the ``shoulder'' seasons (i.e., the spring and/or fall 
seasons), when electricity demand is lower than in the summer, reserves 
are higher, and ozone season compliance requirements are not in effect. 
If multiple units were under the same timeline to complete the retrofit 
projects as soon as feasible from an engineering perspective, this 
could lead to bottlenecks of scheduled outages as each unit attempts to 
start and finish its installation in roughly the same compressed time 
period. Thus, any compliance timeframe that would assume installation 
of new SCR or SNCR controls should encompass multiple shoulder seasons 
to accommodate scheduling of curtailment for control installation 
purposes and better accommodate the regional nature of the program.
    In addition to the coordination of scheduled curtailment, an 
appropriate compliance timeframe should accommodate the additional 
coordination of labor and material supply necessary for any fleet-wide 
mitigation efforts. The total construction labor for a SCR system 
associated with a 500-megawatt (MW) EGU is in the range of 300,000 to 
500,000 man-hours, with boilermakers accounting for

[[Page 31929]]

approximately half of this time.\65\ SNCR installations, while 
generally having shorter individual project timeframes of 10 to 13 
months from bid solicitation to startup, share similar labor and 
material resources and the timing of SNCR installation planning is 
therefore linked to the timing of SCR installation planning. In recent 
industry surveys, one of the largest shortages of union craft workers 
was for boilermakers. This shortage of skilled boilermakers is expected 
to rise due to an anticipated nine percent increase in boilermaker 
labor demand growth by 2026, coupled with expected retirements and 
comparatively low numbers of apprentices joining the workforce.\66\ The 
shortage of and demand for skilled labor, including other craft workers 
critical to pollution control installation, is pronounced in the 
manufacturing industry. The Association of Union Constructors conducted 
a survey of identified labor shortages and found that boilermakers were 
the second-most frequently reported skilled labor market with a labor 
shortage.\67\ Moreover, recovery efforts from the natural disasters of 
Hurricanes Harvey and Irma and wildfires in 2017 are expected to 
further tighten the labor supply market in manufacturing in the near 
term.\68\ The EPA determined that these tight labor market conditions 
within the relevant manufacturing sectors, combined with fleet-level 
mitigation initiatives, would likely lead to some sequencing and 
staging of labor pool usage, rather than simultaneous construction 
across all efforts. This sector-wide trend supports SCR and SNCR 
installation timeframes for a fleet-wide program that exceeds the 
demonstrated single-unit installation timeframe.
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    \65\ Id.
    \66\ Occupational Outlook Handbook. Bureau of Labor Statistics. 
Available at https://www.bls.gov/ooh/construction-and-extraction/boilermakers.htm.
    \67\ Union Craft Labor Supply Survey. The Association of Union 
Constructors. Exhibit 4-2 at page 29. Available at https://www.tauc.org/files/2017_TAUC_UNION_CRAFT_LABOR_SUPPLY_REVISEDBC_FINAL.pdf.
    \68\ Skilled Wage Growth Less Robust, Worker Shortage Still an 
Issue. Industry Week. October 23, 2017. Available at http://www.industryweek.com/talent/skilled-wage-growth-less-robust-worker-shortage-still-issue.
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    In addition to labor supply, NOX post-combustion control 
projects also require materials and equipment such as steel and cranes. 
Sheet metal workers, necessary for steel production, are also reported 
as having well above an average supply-side shortage of labor.\69\ 
This, coupled with growth in steel demand estimated at three percent in 
2018 suggests that there may be a constricted supply of steel needed 
for installation of new post-combustion controls.\70\ Similarly, cranes 
are critical for installation of SCRs, components of which must be 
lifted hundreds of feet in the air during construction. Cranes are also 
facing higher demand during this period of economic growth, with 
companies reporting a shortage in both equipment and 
manpower.71 72 The tightening markets in relevant skilled 
labor, materials, and equipment, combined with the large number of 
installations that could be required fleet-wide under a regional air 
pollution transport program, necessitates longer installation time-
tables relative to what has been historically demonstrated at the unit-
level.
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    \69\ Union Craft Labor Supply Survey. The Association of Union 
Constructors. Exhibit 4-2 at page 29. Available at https://www.tauc.org/files/2017_TAUC_UNION_CRAFT_LABOR_SUPPLY_REVISEDBC_FINAL.pdf.
    \70\ Worldsteel Short Range Outlook. October 16, 2017. Available 
at https://www.worldsteel.org/media-centre/press-releases/2017/worldsteel-Short-Range-Outlook-2017-2018.html.
    \71\ See, e.g., Seattle Has Most Cranes in the Country for 2nd 
Year in a Row--and Lead is Growing. Seattle Times. July 11, 2017. 
Available at https://www.seattletimes.com/business/real-estate/seattle-has-most-cranes-in-the-country-for-2nd-year-in-a-row-and-lead-is-growing/.
    \72\ See RLB Crane Index, January 2018 in the docket for this 
action.
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    The time lag observed between the planning phase and in-service 
date of SCR operations in certain cases also illustrates that site-
specific conditions sometimes lead to installation times of four years 
or longer. For instance, SCR projects for units at the Ottumwa power 
plant (Iowa), Columbia power plant (Wisconsin), and Oakley power plant 
(California) were all in the planning phase in 2014. By 2016, these 
projects were under construction with estimated in-service dates of 
2018.\73\ Similarly, individual SNCR projects can exceed their 
estimated 10 through 13-month construction time frame. For example, 
projects such as SNCR installation at the Jeffrey power plant (Kansas) 
were in the planning phase in 2013, but not in service until 2015.\74\ 
Completed projects, when large in scale, also illustrate how timelines 
can extend beyond the bare minimum necessary for a single unit when the 
project is part of a larger air quality initiative involving more than 
one unit at a plant. For instance, the Big Bend Power Station in 
Florida completed a multi-faceted project that involved adding SCRs to 
all four units as well as converting furnaces, over-fire air changes, 
and making windbox modifications. The time from the initial planning 
stages to completion was a decade.\75\
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    \73\ 2014 EIA Form 860. Schedule 6. Environmental Control 
Equipment.
    \74\ 2013 EIA Form 860, Schedule 6, Environmental Control 
Equipment.
    \75\ Big Bend's Multi-Unit SCR Retrofit. Power Magazine. March 
1, 2010. Available at http://www.powermag.com/big-bends-multi-unit-scr-retrofit/.
---------------------------------------------------------------------------

    While individual unit-level SCR and SNCR projects can average 39 
and 10 months, respectively, from bid to startup, a comprehensive and 
regional emissions reduction effort also requires more time to 
accommodate the labor, materials, and outage coordination for these two 
types of control strategies. Because these post-combustion control 
strategies share similar resource inputs and are part of regional 
emissions reduction programs rather than unit-specific technology 
mandates, the timeframes for one type are inherently linked to the 
other type. This means that SNCR projects cannot be put on an early 
schedule in light of their reduced construction timing without 
impacting the availability of resources for the manufacture and 
installation of SCRs and thus the potential start dates of those 
projects.
    In short, given the market and regulatory circumstances in which 
EPA evaluated this effort, our analysis shows that four years would be 
an expeditious timeframe to coordinate the planning and completion of 
any mitigation efforts necessary in this instance.
b. Non-EGU Control Technologies
    The EPA is also evaluating the feasibility of implementing 
NOX control technologies for non-EGUs in its assessment of 
an appropriate future analytic year. While the EPA did not regulate 
non-EGUs in the CSAPR Update, the rule did evaluate the feasibility of 
NOX controls on non-EGUs in the eastern United States to 
assess whether any such controls could be implemented in time for the 
2017 ozone season. The EPA noted that there was greater uncertainty in 
the assessment of non-EGU point-source NOX mitigation 
potential as compared to EGUs, and therefore explained that more time 
was required for states and the EPA to improve non-EGU point source 
data, including data on existing control efficiencies, additional 
applicable pollution control technologies, and installation times for 
those control technologies. 81 FR 74542. A significant factor 
influencing uncertainty was that the EPA lacked sufficient information 
on the capacity and experience of suppliers and major engineering 
firms' supply chains to determine if they would be able to install the 
required pollution controls for non-EGU sources

[[Page 31930]]

in time for the 2017 ozone season. Further, using the best information 
available to the EPA at that time, the EPA found that there were more 
non-EGU point sources than EGU sources and that these sources on 
average emit less NOX than EGUs. The implication was that 
there were more individual sources that could be controlled, but 
relatively fewer emissions reductions available from each source when 
compared to the number of EGUs and emissions reductions available from 
EGUs. Considering these factors, the EPA found that it was 
substantially uncertain whether significant aggregate NOX 
mitigation would be achievable from non-EGU point sources to address 
the 2008 ozone NAAQS by the 2017 ozone season. Id.
    Although the EPA determined that there were limited achievable 
emissions reductions available from non-EGUs by the 2017 ozone season, 
the EPA acknowledged that it may be appropriate to evaluate potential 
non-EGU emissions reductions achievable on a timeframe after the 2017 
ozone season to assess upwind states' full good neighbor obligation for 
the 2008 ozone NAAQS. 81 FR 74522. In particular, the EPA's preliminary 
assessment indicated that there may be emissions reductions achievable 
from non-EGUs at marginal costs lower than the costs of remaining 
NOX control strategies available for EGUs. Accordingly, in 
assessing an appropriate future analytic year, the EPA is also 
considering the potential implementation timeframes for NOX 
emissions reductions available for non-EGUs. In evaluating potential 
non-EGU emissions reductions in the CSAPR Update, the EPA included 
preliminary estimates of installation times for some non-EGU 
NOX control technologies in a technical support document 
entitled Assessment of Non-EGU NOX Emission Controls, Cost 
of Controls, and Time for Compliance Final Technical Support Document 
(henceforth, ``Final Non-EGU TSD''). These preliminary estimates were 
based on research from a variety of information sources, including:

     Typical Installation Timelines for NOX Emissions 
Control Technologies on Industrial Sources, Institute of Clean Air 
Companies, December 2006 (all sources except cement kilns and 
reciprocating internal combustion engines (RICE)); \76\
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    \76\ Institute of Clean Air Companies. Typical Installation 
Timelines for NOX Emissions Control Technologies on 
Industrial Sources, December 2006. Available at https://c.ymcdn.com/sites/icac.site-ym.com/resource/resmgr/ICAC_NOx_Control_Installatio.pdf.
---------------------------------------------------------------------------

     Cement Kilns Technical Support Document for the NOX 
FIP, US EPA, January 2001; \77\ and
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    \77\ US EPA. Cement Kilns Technical Support Document for the 
NOX FIP. January 2001. Available at https://www.regulations.gov/document?D=EPA-HQ-OAR-2015-0500-0094.
---------------------------------------------------------------------------

     Availability and Limitations of NOX Emission Control 
Resources for Natural Gas-Fired Reciprocating Engine Prime Movers 
Used in the Interstate Natural Gas Transmission Industry, Innovative 
Environmental Solutions Inc., July 2014 (prepared for the INGAA 
Foundation).\78\
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    \78\ INGAA Foundation. Availability and Limitations of 
NOX Emission Control Resources for Natural Gas-Fired 
Reciprocating Engine Prime Movers Used in the Interstate Natural Gas 
Transmission Industry, Innovative Environmental Solutions Inc., July 
2014. Available at http://www.ingaa.org/Foundation/Foundation-Reports/NOX.aspx.

The EPA's analysis in the Final Non-EGU TSD focused on potential 
control technologies within the range of costs considered in the final 
CSAPR Update for EGUs, or those controls available at a marginal cost 
of $3,400 per ton (2011 dollars) of NOX reduced or less. The 
EPA's analysis did not evaluate implementation timeframes or potential 
emissions reductions available from controls at higher cost thresholds. 
See Final Non-EGU TSD at 18. This focus excluded some emissions source 
groups with emissions reduction potential at a marginal cost greater 
than $3,400 per ton, including: industrial/commercial/institutional 
boilers using SCR and low-NOX burners (LNB); and catalytic 
cracking units, process heaters, and coke ovens using LNB and flue gas 
recirculation. However, while emissions reduction potential from these 
source groups is uncertain, the timeframe for these control 
technologies would be subject to similar considerations and limitations 
discussed in the following paragraphs.
    Among the control technologies that were evaluated in the Final 
Non-EGU TSD, the EPA identified six categories of common control 
technologies available for different non-EGU emissions source 
categories. Id. at 19. For four of the technology categories (SNCR, 
SCR, LNB, and mid-kiln firing), the EPA preliminarily estimated that 
such controls for non-EGUs could be installed in approximately 1 year 
or less in some unit-specific cases. Installation time estimates 
presented in the Final Non-EGU TSD begin with control technology bid 
evaluation (bids from vendors) and end with the startup of the control 
technology.\79\ See Final Non-EGU TSD at 20. For the other two 
technology categories (biosolid injection technology (BSI) and OXY-
firing), as well as one emissions source category (RICE), the EPA had 
no installation time estimates or uncertain installation time 
estimates. For example, the EPA found that the use of BSI is not 
widespread, and therefore the EPA does not have reliable information 
regarding the time required to install the technology on cement kilns. 
The installation timing for OXY-firing is similarly uncertain because 
the control technology is installed only at the time of a furnace 
rebuild, and such rebuilds occur at infrequent intervals of a decade or 
more.
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    \79\ In this document, we present different installation time 
estimates for SCRs for EGUs and non-EGUs. These installation times 
are not inconsistent because: (i) The EGU time estimate of 39 months 
mentioned above is based on multi-boiler installation and factors in 
a pre-vendor bid engineering study consideration; and (ii) the non-
EGU SCR installation time estimates are based on single-unit 
installation and do not factor in pre-vendor bid evaluation.
---------------------------------------------------------------------------

    For those categories for which preliminary estimates were 
available, as noted in the Final Non-EGU TSD, the single-unit 
installation time estimates provided do not account for additional 
important considerations in assessing the full amount of time needed 
for installation of NOX control measures at non-EGUs; those 
considerations include time, labor, and materials needed for 
programmatic adoption of measures and time required for installing 
controls on multiple sources in a few to several non-EGU sectors across 
the region.
    The preliminary estimates of installation time shown in the Final 
Non-EGU TSD are for installation at a single source and do not account 
for the time required for installing controls to achieve sector-wide 
compliance. When considering installation of control measures on 
sources regionally and across non-EGU sectors, the time for full 
sector-wide compliance is uncertain, but it is likely longer than the 
installation times shown for control measures as mentioned above for 
individual sources in the Final Non-EGU TSD. As discussed earlier with 
respect to EGUs, regional, sector-wide compliance could be slowed down 
by limited vendor capacity, limited available skilled labor for 
manufacturers such as boilermakers (who produce steel fabrications, 
including those for pollution control equipment), availability of raw 
materials and equipment (e.g., cranes) for control technology 
construction, and bottlenecks in delivery and installation of control 
technologies. Some of the difficulties with control technology 
installation as part of regional, sector-wide compliance at non-EGUs, 
such as availability of skilled labor and materials, could also have an 
impact on monitor installation at such sources.

[[Page 31931]]

EPA currently has insufficient information on vendor capacity and 
limited experience with suppliers of control technologies and major 
engineering firms, which results in uncertainty in the installation 
time estimates for non-EGU sectors. In summary, there is significant 
uncertainty regarding the implementation timeframes for various 
NOX control technologies for non-EGUs. While the EPA has 
developed preliminary estimates for some potential control 
technologies, these estimates do not account for additional 
considerations such as the impacts of sector- and region-wide 
compliance. For purposes of this analysis, the EPA believes that it is 
reasonable to assume that it is likely that an expeditious timeframe 
for installing sector- or region-wide controls on non-EGU sources may 
collectively require four years or more.
3. Focusing on 2023 for Analysis
    As discussed in section III.B, the EPA weighed several factors to 
identify an appropriate future analytic year for evaluating interstate 
transport obligations for the 2008 ozone NAAQS. First, the EPA 
identified the relevant attainment dates to guide the EPA's 
consideration as 2021 and 2027, respectively the Serious and Severe 
area attainment dates for the 2008 ozone NAAQS.
    Second, the EPA identified and analyzed the feasibility and timing 
needed for installing additional NOX emissions controls. As 
discussed in section III.B.2, the EPA believes it is appropriate to 
assume that planning for, installing, and commencing operation of new 
controls, regionally, for EGUs and non-EGUs would take up to 48 months, 
and possibly more in some cases, following promulgation of a final rule 
requiring appropriate emissions reductions. This period of time 
reflects, among other considerations, the time needed to regionally 
develop new post-combustion SCR projects--systems that continue to 
represent the engineering gold-standard in terms of reducing 
NOX from the U.S. power sector.
    To determine how this feasibility assessment should influence 
potential compliance timeframes, the EPA believes it is appropriate to 
consider the anticipated date of promulgation of a rule that would set 
any appropriate emissions reduction requirements, since regulated 
entities cannot be expected or required to take action to comply with a 
rule prior to its promulgation. The EPA, therefore, considered the 
timeframe in which a future rulemaking that might require such 
emissions reductions would likely be finalized.
    The EPA is subject to several statutory and court-ordered deadlines 
to issue FIPs (or, alternatively, to fully approve a SIP) to address 
the requirements of the good neighbor provision for the 2008 ozone 
NAAQS for several states. An August 12, 2017 statutory deadline has 
passed for the EPA to act with respect to 13 states.\80\ The EPA also 
has several upcoming statutory deadlines in 2018 and 2019 to address 
these requirements for eight other CSAPR Update states.\81\ The 
timeframe for the EPA's action to resolve the obligation as to five of 
those states is the subject of litigation in the United States District 
Court for the Southern District of New York. The EPA is subject to 
court-ordered deadlines to sign and disseminate a proposed action fully 
addressing the good neighbor obligations under the 2008 ozone NAAQS for 
those five states by no later than June 29, 2018, and to promulgate a 
final action addressing these requirements by December 6, 2018.\82\ As 
noted earlier, the EPA is also subject to a court-ordered deadline of 
June 30, 2018, for the EPA to address these requirements for 
Kentucky,\83\ which the EPA intends to address in a separate 
rulemaking. Considering the EPA's conclusion that four years is an 
expeditious timeframe for implementation of any of the control 
strategies considered herein, compliance is likely not feasible until 
the 2023 ozone season. In other words, 48 months from a final rule 
promulgated in December 2018 would be December 2022, after which the 
next ozone season begins in May 2023. Considering the time necessary to 
implement the controls calculated from a realistic timeframe in which 
EPA expects to promulgate a final rule requiring such controls, the EPA 
believes that such reductions on a variety of sources across the region 
are unlikely to be implemented for a full ozone season until 2023.
---------------------------------------------------------------------------

    \80\ 80 FR 39961 (finding that states failed to make complete 
submissions that address the requirements of section 
110(a)(2)(D)(i)(I) related to the interstate transport of pollution 
as to the 2008 ozone NAAQS).
    \81\ The EPA has deadlines to promulgate FIPs for Indiana (81 FR 
38957), Ohio (81 FR 38957) and New Jersey (81 FR 38963) by July 15, 
2018; for Maryland (81 FR 47040) by August 19, 2018; for Louisiana 
(81 FR 53308), Texas (81 FR 53284) and Wisconsin (81 FR 53309) by 
September 12, 2018; and for New York (81 FR 58849) by September 26, 
2018.
    \82\ Order, New York v. Pruitt, No. 1:18-cv-00406-JGK (S.D.N.Y. 
June 12, 2018).
    \83\ Order, Sierra Club v. Pruitt, No. 3:15-cv-04328 (N.D. Cal. 
May 23, 2017).
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    Finally, consistent with the court's holding in North Carolina, the 
Agency considers this timing in light of upcoming attainment dates for 
the 2008 ozone NAAQS. While 2023 is later than the next attainment date 
for nonattainment areas classified as Serious (i.e., July 20, 2021), 
for the reasons discussed above the EPA does not believe it is 
realistically possible that substantial emissions control requirements 
could be promulgated and implemented by that Serious area attainment 
date. Rather, the most expeditious timeframe in which additional 
control strategies could be implemented at both EGUs and non-EGUs is 
four years after promulgation of a final rule requiring appropriate 
emissions reductions. At the same time, the EPA does not believe that 
it should generally take longer than 2023 to install emissions controls 
on a regional basis, based on the analysis above. Therefore, there is 
no basis to postpone all emissions reductions to the next attainment 
date after 2023, which is for nonattainment areas classified as Severe 
(i.e., July 20, 2027). Accordingly, the EPA believes implementation of 
additional emissions reductions by 2023 is the earliest feasible 
timeframe that could be reasonably required of EGU and non-EGU sources 
that would be potentially subject to control requirements. Although 
this year does not precisely align with a particular attainment date, 
it reflects the year that is as expeditious as practicable for region-
wide implementation, while also taking into account the relevant 
attainment dates.
    Given the current stage of the 2008 ozone implementation cycle, the 
EPA's feasibility analysis set forth above, the relevant attainment 
dates, and the courts' holdings in North Carolina and EME Homer City 
II, the EPA believes that 2023 is the most appropriate year for all 
states covered in this action, to assess downwind air quality and to 
evaluate any remaining requirements under the good neighbor provision 
for the 2008 ozone NAAQS. The EPA is requesting comment on the use of 
2023 as a reasonable year for this assessment.

C. Air Quality Analysis

    In this section, the Agency describes the air quality modeling 
performed consistent with step 1 of the framework described in section 
III.A, to identify locations where it expects nonattainment or 
maintenance problems with respect to the 2008 ozone NAAQS in the 2023 
analytic year. This section includes information on the air quality 
modeling platform used in support of the proposed determination with a 
focus on the base year and future base case emissions inventories. The 
May 2018

[[Page 31932]]

Air Quality Modeling Technical Support Document (AQM TSD) in the docket 
for this rule contains more detailed information on the air quality 
modeling for 2023 used to support this rulemaking.
    The EPA provided an opportunity to comment on the air quality 
modeling platform and air quality modeling results that are used in 
this proposed determination when it published a Notice of Data 
Availability (82 FR 1733) on January 6, 2017, which provided the 
preliminary modeling results for the 2023 analytic year. Specifically, 
in the NODA the EPA requested comment on the data and methodologies 
related to the 2011 and 2023 emissions and the air quality modeling to 
project 2023 ozone concentrations and ozone contributions. While the 
EPA issued this NODA to provide information to states for the 70 ppb 
2015 ozone NAAQS, the modeling approaches and future year projection 
methods were also applicable for the 75 ppb 2008 ozone NAAQS. In fact, 
commenters explicitly commented on these methods with respect to the 
2008 ozone NAAQS. The EPA considered comments received on the NODA in 
the development of air quality modeling analysis used in this proposed 
determination.
    The modeling results presented here were originally released to the 
public with an accompanying memorandum on October 27, 2017.\84\
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    \84\ Memorandum from Stephen D. Page, Director, Office of Air 
Quality Planning and Standards, to Regional Air Division Directors, 
Regions 1-10, Supplemental Information on the Interstate Transport 
State Implementation Plan Submissions for the 2008 Ozone National 
Ambient Air Quality Standards under Clean Air Act Section 
110(a)(2)(D)(i)(I) (Oct. 27, 2017), available at https://www.epa.gov/airmarkets/october-2017-memo-and-supplemental-information-interstate-transport-sips-2008-ozone-naaqs.
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1. Definition of Nonattainment and Maintenance Receptors
    In this action, the EPA is continuing to apply the CSAPR Update 
approach to identifying nonattainment and maintenance receptors for the 
2008 ozone NAAQS in the 2023 analytic year. The EPA here describes the 
analytical approach pursued in the CSAPR and CSAPR update with regard 
to the good neighbor requirement for the 2008 ozone NAAQS. For 
consistency's sake, the analysis and discussion underlying and 
presented in this proposal adheres to that analytical approach. 
However, as noted previously, EPA has identified a number of potential 
flexibilities in identifying downwind air quality problems for states 
developing good neighbor SIPs for the 2015 ozone NAAQS.\85\ However, 
the EPA finds that it is reasonable to use the same methodology that 
was used to identify upwind states' good neighbor obligations under the 
CSAPR Update because this rule addresses interstate transport with 
respect to the same NAAQS and the same states as the ones at issue in 
that action.\86\
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    \85\ See supra note 43. These potential flexibilities include: 
evaluation of alternative methodologies to give independent meaning 
to the term ``interfere with maintenance under CAA section 
110(a)(2)(D)(i)(I); identification of maintenance receptors at risk 
of exceeding the NAAQS using an approach that does not rely on the 
projection of maximum design values; assessment of current and 
projected emissions reductions and whether downwind areas have 
considered and/or utilized available mechanisms for regulatory 
relief; and consideration of model performance.
    \86\ 81 FR 74533.
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    To give independent effect to both the ``contribute significantly 
to nonattainment'' and the ``interfere with maintenance'' prongs of 
section 110(a)(2)(D)(i)(I) for the 2008 ozone NAAQS, consistent with 
the D.C. Circuit's opinion in North Carolina, the EPA separately 
identified downwind areas expected to be in nonattainment of the 2008 
ozone NAAQS and downwind areas expected to have problems maintaining 
the 2008 ozone NAAQS.
    Specifically, the EPA has identified as nonattainment receptors 
those monitors that both currently measure nonattainment based on 
measured 2014-2016 design values \87\ and that the EPA projects will be 
in nonattainment for the 2008 ozone NAAQS in 2023 (i.e., are projected 
to have average design values that exceed the NAAQS).
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    \87\ The ozone design value at a particular monitoring site is 
the 3-year average of the annual 4th highest daily maximum 8-hour 
ozone concentration at that site. See 40 CFR part 50, Appendix P.
---------------------------------------------------------------------------

    The EPA has identified maintenance receptors as those receptors 
that would have difficulty maintaining the relevant NAAQS in a scenario 
that accounts for historical variability in air quality at that 
receptor. The variability in air quality was determined by evaluating 
the ``maximum'' future design value at each receptor based on a 
projection of the maximum measured design value over the relevant base-
year period. The EPA interprets the projected maximum future design 
value to be a potential future air quality outcome consistent with the 
meteorology that yielded maximum measured concentrations in the ambient 
data set analyzed for that receptor. The EPA also recognizes that 
previously experienced meteorological conditions (e.g., dominant wind 
direction, temperatures, air mass patterns) promoting ozone formation 
that led to maximum concentrations in the measured data may reoccur in 
the future. Therefore, the maximum design value gives a reasonable 
projection of future air quality at the receptor under a scenario in 
which such conditions do, in fact, reoccur. The projected maximum 
design value is used to identify downwind areas where emissions from 
upwind states could therefore interfere with the area's ability to 
maintain the NAAQS. For this proposal, the EPA assesses the magnitude 
of the maximum projected design value for 2023 at each receptor in 
relation to the 2008 ozone NAAQS. Where that value exceeds the NAAQS, 
the EPA determines that receptor to be a ``maintenance'' receptor for 
purposes of defining interference with maintenance, consistent with the 
method used in CSAPR and upheld by the D.C. Circuit in EME Homer City 
II.\88\ That is, monitoring sites with a maximum projected design value 
that exceeds the NAAQS in 2023 are considered to have a maintenance 
problem in 2023.\89\
---------------------------------------------------------------------------

    \88\ See 795 F.3d at 136.
    \89\ All nonattainment receptors also, by definition, meet EPA's 
criteria for identifying maintenance receptors--i.e., in addition to 
currently measuring nonattainment and having projected average 
design values that exceed the NAAQS, the receptors also would have 
difficulty maintaining the NAAQS accounting for variability in air 
quality at the receptor. The EPA refers to maintenance receptors 
that are not also nonattainment receptors as ``maintenance-only'' 
receptors.
---------------------------------------------------------------------------

    Maintenance-only receptors therefore include those sites where the 
projected maximum design value exceeds the NAAQS, but the projected 
average design value is at or below the NAAQS. In addition, those sites 
that are currently measuring clean data (i.e., are at or below the 2008 
ozone NAAQS), but are projected to be in nonattainment based on the 
average design value (and that, by definition, are projected to have a 
maximum design value above the standard) are also identified as 
maintenance-only receptors. Unlike nonattainment receptors, the EPA did 
not consider current clean monitored data to disqualify a receptor from 
being identified as a maintenance receptor in order to account for the 
possibility that certain areas would fail to maintain the NAAQS in the 
future, even though they may be currently attaining the NAAQS. North 
Carolina, 531 F.3d at 910-11 (finding that failure to give independent 
significance to the maintenance prong ``provides no protection for 
downwind areas that, despite EPA's predictions, still find themselves 
struggling to meet NAAQS due to upwind interference'').
    For further details regarding the EPA's identification of receptors 
in the CSAPR Update, see 81 FR 74526.

[[Page 31933]]

2. Overview of Air Quality Modeling Platform
    The EPA performed nationwide photochemical modeling for 2023 to 
identify nonattainment and maintenance receptors relevant for the 2008 
ozone NAAQS. For this proposed rule, the EPA performed air quality 
modeling for two emissions scenarios: (1) a 2011 base year; and (2) the 
2023 analytic year (i.e., a business-as-usual scenario in 2023: One 
without any additional interstate ozone transport requirements beyond 
those imposed by the CSAPR Update).
    The 2011 base year has previously been used to support the CSAPR 
Update proposal and final rule. The EPA chose to continue using 2011 as 
the base year because when EPA's analyses commenced, 2011 was the most 
recent emissions modeling platform available that included future year 
projected inventories, as are needed for transport analyses. Using 2011 
as a base year also remains appropriate from the standpoint of good 
modeling practice. The meteorological conditions during the summer of 
2011 were generally conducive for ozone formation across much of the 
U.S., particularly the eastern U.S. As described in the AQM TSD, the 
EPA's guidance for ozone attainment demonstration modeling, hereafter 
referred to as the modeling guidance, recommends modeling a time period 
with meteorology conducive to ozone formation for purposes of 
projecting future year design values.\90\ The EPA therefore believes 
that meteorological conditions and emissions during the summer of 2011 
provide an appropriate basis for projecting 2023 ozone concentrations.
---------------------------------------------------------------------------

    \90\ U.S. Environmental Protection Agency, 2014. Modeling 
Guidance for Demonstrating Attainment of Air Quality Goals for 
Ozone, PM2.5, and Regional Haze, Research Triangle Park, 
NC, available at http://www.epa.gov/ttn/scram/guidance/guide/Draft_O3-PM-RH_Modeling_Guidance-2014.pdf.
---------------------------------------------------------------------------

    For this proposal, the EPA used the Comprehensive Air Quality Model 
with Extensions (CAMx) version 6.40 \91\ to simulate pollutant 
concentrations for the 2011 base year and the 2023 future year 
scenarios. This version of CAMx was the most recent publicly available 
version of this model at the time that the EPA performed air quality 
modeling for this proposed rule. CAMx is a grid cell-based, multi-
pollutant photochemical model that simulates the formation and fate of 
ozone and fine particles in the atmosphere. The CAMx model applications 
were performed for a modeling region (i.e., modeling domain) that 
covers the contiguous 48 United States, the District of Columbia, and 
adjacent portions of Canada and Mexico using grid cells with a 
horizontal resolution of 12 km x 12 km. A map of the air quality 
modeling domain is provided in the AQM TSD.
---------------------------------------------------------------------------

    \91\ CAMx v6.40 was the most recent public release version of 
CAMx at the time the EPA updated its modeling in fall 2017. 
Comprehensive Air Quality Model with Extensions version 6.40 User's 
Guide. Ramboll Environ, December 2016, available at http://www.camx.com/.
---------------------------------------------------------------------------

    The 2011-based air quality modeling platform includes 2011 base 
year emissions, 2023 future year projections of these emissions, and 
2011 meteorology for air quality modeling with CAMx. In the remainder 
of this section, the EPA provides an overview of the 2011 and 2023 
emissions inventories and the methods for identifying nonattainment and 
maintenance receptors along with a list of 2023 baseline nonattainment 
and maintenance receptors in the U.S.
    To ensure the reliability of its modeling results, the EPA 
conducted an operational model performance evaluation of the 2011 
modeling platform by comparing the 8-hour daily maximum ozone 
concentrations predicted during the May through September ozone season 
to the corresponding measured concentrations in 2011. This evaluation 
generally followed the approach described in the modeling guidance. 
Details of the model performance evaluation are described in the AQM 
TSD. The model performance results indicate that the 8-hour daily 
maximum ozone concentrations predicted by the 2011 CAMx modeling 
platform generally reflect the corresponding magnitude of observed 8-
hour ozone concentrations on high ozone days in the 12-km U.S. modeling 
domain. These results provide confidence in the ability of the modeling 
platform to provide a reasonable projection of expected future year 
ozone concentrations and contributions.
3. Emissions Inventories
    The EPA developed emissions inventories for this rule, including 
emissions estimates for EGUs, non-EGU point sources, stationary 
nonpoint sources, onroad mobile sources, nonroad mobile sources, 
wildfires, prescribed fires, and biogenic emissions. The EPA's air 
quality modeling relies on this comprehensive set of emissions 
inventories because emissions from multiple source categories are 
needed to model ambient air quality and to facilitate comparison of 
model outputs with ambient measurements.
    To prepare the emissions inventories for air quality modeling, the 
EPA processed the emissions inventories using the Sparse Matrix 
Operator Kernel Emissions (SMOKE) Modeling System version 3.7 to 
produce the gridded, hourly, speciated, model-ready emissions for input 
to the CAMx air quality model. Additional information on the 
development of the emissions inventories and on datasets used during 
the emissions modeling process for this proposed rule is provided in 
the October 2017 Technical Support Document ``Additional Updates to 
Emissions Inventories for the Version 6.3, 2011 Emissions Modeling 
Platform for the Year 2023'' (Proposed Rule Emissions Modeling 
TSD).\92\
---------------------------------------------------------------------------

    \92\ This TSD is also available in the docket for this proposed 
rule and at https://www.epa.gov/air-emissions-modeling/additional-updates-2011-and-2023-emissions-version-63-platform-technical.
---------------------------------------------------------------------------

    The emissions inventories, methodologies, and data used for the air 
quality modeling for this proposed rule incorporate public comments 
received on the January 2017 NODA. The updates resulting from comments 
received on this NODA are documented in the Proposed Rule Emissions 
Modeling TSD. The emissions inventories for this proposed rule were the 
result of several iterations of comments on the data and methods used 
in the 2011 emissions modeling platform. The initial modeling platform 
based on the 2011 National Emissions Inventory (NEI) was released for 
public comment in November 2013 through a NODA (78 FR 70935). Future 
year inventories for 2018 were released shortly thereafter through a 
separate NODA in January 2014 (79 FR 2437). Updated inventories for 
2011 and the year 2017 were released for public comment in August 2015 
through a notice prior to the proposed CSAPR Update. 80 FR 46271. The 
comments were incorporated into inventories used for the proposal 
modeling in this action. During 2016, the comments received on the 
proposal inventories were incorporated into the final CSAPR Update 
inventories for years 2011 and 2017. 81 FR 74527. In late 2016, 
inventories for the year 2023 were developed using methods similar to 
those of the CSAPR Update, and the resulting inventories were released 
in the January 2017 NODA described above.\93\
---------------------------------------------------------------------------

    \93\ Technical support documents are available for each 
iteration of the inventories on EPA's emissions modeling website: 
https://www.epa.gov/air-emissions-modeling/2011-version-6-air-emissions-modeling-platforms.
---------------------------------------------------------------------------

    The EPA emissions data representing the year 2011 supports air 
quality modeling of a base year from which future air quality could be 
forecasted. The 2011 emissions inventories used in

[[Page 31934]]

the air quality modeling were based on the inventories released with 
the January 2017 NODA with updates incorporated as a result of comments 
on the NODA and as a result of improved data and methods that became 
available after the NODA modeling was completed. The future base case 
scenario modeled for 2023 includes a representation of changes in 
activity data and of predicted emissions reductions from on-the-books 
actions, including planned emissions control installations and 
promulgated federal measures that affect anthropogenic emissions.\94\ 
The emissions inventories for air quality modeling include sources that 
are held constant between the base and future years, such as biogenic 
emissions and emissions from agricultural, wild and prescribed 
fires.\95\ The emissions inventories used for Canada were received from 
Environment and Climate Change Canada in April 2017 and were provided 
for the years 2013 and 2025. This was the first time that future year 
projected inventories for Canada were provided directly by Environment 
and Climate Change Canada and the new inventories are thought to be an 
improvement over inventories projected by EPA. The EPA used the 
Canadian emissions inventories without adjusting the emissions to the 
represented year because the EPA lacks specific knowledge regarding 
Canadian emissions trends and because the interval of years (i.e., 12) 
was the same as that used for the U.S. modeling which relied on 2011 to 
2023 interval. For Mexico, inventory data was based on a 2023 run of 
MOVES-Mexico. For area, nonroad, and point source emissions in Mexico, 
EPA used the Inventario Nacional de Emisiones de Mexico using 2018 and 
2025 data projections to interpolate 2023 estimates.
---------------------------------------------------------------------------

    \94\ Biogenic emissions and emissions from wildfires and 
prescribed fires were held constant between 2011 and 2023 since: (1) 
These emissions are tied to the 2011 meteorological conditions; and 
(2) the focus of this rule is on the contribution from anthropogenic 
emissions to projected ozone nonattainment and maintenance.
    \95\ As recommended in the modeling guidance, the acceptability 
of model performance was judged by considering the 2011 CAMx 
performance results in light of the range of performance found in 
recent regional ozone model applications. These other modeling 
studies represent a wide range of modeling analyses that cover 
various models, model configurations, domains, years and/or 
episodes, and chemical mechanisms. Overall, the ozone model 
performance results for the 2011 CAMx simulations are within the 
range found in other recent peer-reviewed and regulatory 
applications. The model performance results, as described in the AQM 
TSD, demonstrate that the predictions from the 2011 modeling 
platform correspond to measured data in terms of the magnitude, 
temporal fluctuations, and spatial differences for 8-hour daily 
maximum ozone.
---------------------------------------------------------------------------

    The modeled annual NOX and SO2 emissions for 
EGUs for the year 2011 are based primarily on data from continuous 
emissions monitoring systems (CEMS), with other EGU pollutants 
estimated using emissions factors and annual heat input data reported 
to the EPA. For EGUs without CEMS, the EPA used data submitted to the 
NEI by the states. The modeled 2011 inventories include some updates to 
2011 EGU stack parameters and emissions made in response to comments on 
the January 2017 NODA. For more information on the details of how the 
2011 EGU emissions were developed and prepared for air quality 
modeling, see the Proposed Rule Emissions Modeling TSD.
    As summarized in the October memo, and described in detail in the 
Proposed Rule Emissions Modeling TSD, the EPA projected future 2023 
baseline EGU emissions using an approach that is consistent with the 
EGU projections that the EPA used in the CSAPR Update, specifically 
using the EGU projection methodology used to develop the ``budget-
setting base case.'' 81 FR 74543.\96\ The EGU projection begins with 
2016 reported SO2 and NOX data for units 
reporting under the Acid Rain and CSAPR programs under 40 CFR part 75. 
These were the most recent ozone season data available at the time of 
the EPA's analysis. The EPA first held these observed emissions levels 
constant for its 2023 estimates, but then made some unit-specific 
adjustments to emissions to account for upcoming retirements, post-
combustion control retrofits, coal-to-gas conversions, combustion 
controls upgrades, new units, CSAPR Update compliance, state rules, and 
Best Available Retrofit Technology (BART) requirements under the 
regional haze program of the CAA.\97\ The resulting estimated EGU 
emissions values are therefore based on the latest reported operational 
data combined with known and anticipated fleet and pollution controls 
changes. For emissions from EGUs not reporting under 40 CFR part 75, 
the EPA largely relied on unadjusted 2011 NEI data for its 2023 
assumptions.\98\ Additional details are provided in the Proposed Rule 
Emissions Modeling TSD.
---------------------------------------------------------------------------

    \96\ Also see the Ozone Transport Policy Analysis Final Rule 
Technical Support Document. EPA. August 2016. Available at https://www.epa.gov/sites/production/files/2017-05/documents/ozone_transport_policy_analysis_final_rule_tsd.pdf.
    \97\ The EPA uses the U.S. EIA Form 860 as a source for upcoming 
controls, retirements, and new units.
    \98\ Available at https://www.epa.gov/air-emissions-modeling/2011-version-63-platform.
---------------------------------------------------------------------------

    The 2011 non-EGU point source emissions in the 2011 base case 
inventory generally match those in the 2011 NEI version 2.\99\ Prior to 
air quality modeling, the emissions inventories must be processed into 
a format that is appropriate for the air quality model to use. Details 
on the development and processing of the emissions for 2011 and on the 
development of the 2023 non-EGU emissions inventories are available in 
the Proposed Rule Emissions Modeling TSD. Projection factors and 
percent reductions used in this proposal to estimate 2023 emissions 
inventories reflect comments received through the January 2017 NODA, 
along with emissions reductions due to national and local rules, 
control programs, plant closures, consent decrees and settlements. The 
Proposed Rule Emissions Modeling TSD contains details on the factors 
used and on their respective impacts on the emissions inventories.
---------------------------------------------------------------------------

    \99\ For more information on the 2011 National Emissions 
Inventory version 2, see https://www.epa.gov/air-emissions-inventories/2011-national-emissions-inventory-nei-technical-support-document.
---------------------------------------------------------------------------

    A recent and important methodological update to the emissions 
inventory implemented after the release of the January 2017 NODA is a 
revised methodology for estimating point and nonpoint 2023 emissions 
from the oil and gas sector. The projection factors used in the updated 
2023 oil and gas emissions inventory incorporate state-level factors 
based on historical growth from 2011-2015 and region-specific factors 
that represent projected growth from 2015 to 2023. The 2011-2015 state-
level factors were based on historical state oil and gas production 
data published by the U.S. Department of Energy's Energy Information 
Administration (EIA), while the 2015-2023 factors are based on 
projected oil and gas production in EIA's 2017 Annual Energy Outlook 
(AEO) Reference Case without the Clean Power Plan for the six EIA 
supply regions. The 2017 AEO was the latest available at the time the 
modeling was performed. Details on the revised methodology that the EPA 
used to project oil and gas emissions to 2023, as well as changes to 
the base year 2011 and future year 2023 emissions inventories for other 
sectors, can be found in the Proposed Rule Emissions Modeling TSD.
    The EPA developed the onroad mobile source emissions using the 
EPA's Motor Vehicle Emissions Simulator, version 2014a (MOVES2014a). 
The agency computed

[[Page 31935]]

these emissions within SMOKE by multiplying the MOVES-based emissions 
factors with the activity data appropriate to each year of modeling. 
MOVES2014a reflects projected changes to fuel usage and onroad mobile 
control programs finalized as of March 2014. Impacts of rules that were 
in effect in 2011 are reflected in the 2011 base year emissions at a 
level that corresponds to the extent to which each rule had penetrated 
the fleet and fuel supply by that year. Local control programs such as 
the California Low Emission Vehicle (LEV) III program, also implemented 
in states other than California, are included in the onroad mobile 
source emissions. Activity data for onroad mobile sources, such as the 
vehicle miles traveled in 2023, were projected for future year using 
trends identified in AEO 2016.
    The commercial marine category 3 vessel (``C3 marine'') emissions 
in the 2011 base case emissions inventory for this rule are equivalent 
to those in the 2011NEIv2 with the inclusion of updated emissions for 
California. These emissions reflect reductions associated with the 
Emissions Control Area proposal to the International Maritime 
Organization control strategy (EPA-420-F-10-041, August 2010); 
reductions of NOX, VOC, and CO emissions for new C3 engines 
that went into effect in 2011; and fuel sulfur limits that went into 
effect as early as 2010. The cumulative impacts of these rules through 
2023 are incorporated in the 2023 projected emissions for C3 marine 
sources. An update made for this modeling was to treat the larger C3 
marine sources with plume rise in the modeling, thereby putting the 
emissions into model layers higher than ground-level. This was done 
because the ships have stacks that release emissions higher than the 
20-meter threshold for the ground-level layer in the air quality model. 
The height at which the emissions are inserted into the model impacts 
how the emissions are transported within the model. The emissions from 
the smaller category 1 (C1) and category 2 (C2) vessels are still 
released into the ground-level layer of the model.
    To develop the nonroad mobile source emissions inventories other 
than C3 marine for the modeling platform, the EPA used monthly, county, 
and process level emissions output from the National Mobile Inventory 
Model (NMIM) (http://www.epa.gov/otaq/nmim.htm). The nonroad mobile 
emissions control programs include reductions to locomotives, diesel 
engines, and marine engines, along with standards for fuel sulfur 
content and evaporative emissions. A comprehensive list of control 
programs included for mobile sources is available in the Proposed Rule 
Emissions Modeling TSD.
    The emissions for stationary nonpoint sources in the 2011 base case 
emissions inventory are largely consistent with those in the 2011NEIv2. 
2023 estimates were projected using a variety of factors, including AEO 
2017 projections for 2023 and state projection factors using EIA data 
from 2011-2015. For more information on the nonpoint sources in the 
2011 base case inventory, see the Proposed Rule Emissions Modeling TSD 
and the 2011NEIv2 TSD. Based on comments from the January 2017 NODA, 
where states provided the EPA with information about projected control 
measures or changes in nonpoint source emissions, the EPA incorporated 
that information into its projections. These changes were limited and 
are discussed in the Proposed Rule Emissions Modeling TSD.
4. Air Quality Modeling To Identify Nonattainment and Maintenance 
Receptors
    The following summarizes the procedures for projecting future-year 
8-hour ozone average and maximum design values to 2023 to determine 
nonattainment and maintenance receptors. Consistent with the EPA's 
modeling guidance, the agency uses the air quality modeling results in 
a ``relative'' sense to project future concentrations. That is, the 
ratios of future year model predictions to base year model predictions 
are used to adjust ambient ozone design values up or down depending on 
the relative (percent) change in model predictions for each location. 
The modeling guidance recommends using measured ozone concentrations 
for the 5-year period centered on the base year as the air quality data 
starting point for future year projections. This average design value 
is used to dampen the effects of inter-annual variability in 
meteorology on ozone concentrations and to provide a reasonable 
projection of future air quality at the receptor under ``average'' 
conditions. Because the base year for this rule is 2011, the EPA is 
using the base period 2009-2013 ambient ozone design value data to 
project 2023 average design values in a manner consistent with the 
modeling guidance.
    The approach for projecting future ozone design values involved the 
projection of an average of up to three design value periods, which 
include the years 2009-2013 (design values for 2009-2011, 2010-2012, 
and 2011-2013). The 2009-2011, 2010-2012, and 2011-2013 design values 
are accessible at www.epa.gov/airtrends/values.html. The average of the 
three design values creates a ``5-year weighted average'' value. The 5-
year weighted average values were then projected to 2023. To project 8-
hour ozone design values, the agency used the 2011 base year and 2023 
future base-case model-predicted ozone concentrations to calculate 
relative response factors (RRFs) for the location of each monitoring 
site. The RRFs were then applied to actual monitored data, i.e., the 
2009-2013 average ozone design values (to generate the projected 
average design values) and the individual design values for 2009-2011, 
2010-2012, and 2011-2013 (to generate potential maximum design values). 
Details of this approach are provided in the Proposed Rule AQM TSD.
    The EPA considers projected design values that are greater than or 
equal to 76.0 ppb to be violating the 2008 ozone NAAQS in 2023. As 
noted previously, nonattainment receptors are those sites that have 
projected average design values greater than the 2008 ozone NAAQS and 
are also violating the NAAQS based on the most recent measured air 
quality data. Therefore, as an additional step, for those sites that 
are projected to be violating the NAAQS based on the average design 
values in 2023, the EPA examined the most recent measured design value 
data to determine if the site was currently violating the NAAQS. For 
this proposal, the agency examined ambient data for the 2014-2016 
period, which are the most recent available, certified measured design 
values at the time of this rule.
    As discussed above, maintenance-only receptors include both: (1) 
Those sites with projected average and maximum design values above the 
NAAQS that are currently measuring clean data; and (2) those sites with 
projected average design values below the level of the NAAQS, but with 
projected maximum design values of 76.0 ppb or greater.
    In projecting these future year design values, the EPA applied its 
own modeling guidance,\100\ which recommends using model predictions 
from the ``3 x 3'' array of grid cells surrounding the location of the 
monitoring site to calculate the relative response factors and identify 
future areas of nonattainment. In addition, in

[[Page 31936]]

light of comments on the January 2017 NODA and other analyses, the EPA 
also projected 2023 design values based on a modified version of this 
approach for those monitoring sites located in coastal areas. In brief, 
in the alternative approach, the EPA eliminated from the design value 
calculations those modeling data in grid cells not containing a 
monitoring site that are dominated by water (i.e., more than 50 percent 
of the land use in the grid cell is water).\101\ For each individual 
monitoring site, the EPA is providing the base period 2009-2013 average 
and maximum design values, 2023 projected average and maximum design 
values based on both the ``3 x 3'' approach and the alternative 
approach affecting coastal sites, and 2014-2016 measured design values. 
As discussed further below, under both the 3 x 3 approach and the 
alternative approach all monitoring sites in the Eastern U.S. are 
modeled to be clean for the 2008 ozone NAAQS in 2023. Thus, according 
to the EPA's findings, there will be no remaining nonattainment or 
maintenance receptors in the eastern U.S. in 2023.
---------------------------------------------------------------------------

    \100\ U.S. Environmental Protection Agency, 2014. Modeling 
Guidance for Demonstrating Attainment of Air Quality Goals for 
Ozone, PM2.5, and Regional Haze. http://www.epa.gov/ttn/scram/guidance/guide/Draft_O3-PM-RH_Modeling_Guidance-2014.pdf.
    \101\ A model grid cell is identified as a ``water'' cell if 
more than 50 percent of the grid cell is water based on the 2006 
National Land Cover Database. Grid cells that meet this criterion 
are treated as entirely over water in the Weather Research Forecast 
(WRF) modeling used to develop the 2011 meteorology for EPA's air 
quality modeling.
---------------------------------------------------------------------------

    Tables III.C-1 and III.C-2 contain the ambient 2009-2013 base 
period average and maximum 8-hour ozone design values, the 2023 
projected baseline average and maximum design values, and the ambient 
2014-2016 design values for the air quality monitors that were 
identified in the CSAPR Update as having remaining problems attaining 
or maintaining the 2008 ozone NAAQS in 2017, even with CSAPR Update 
implementation. Table III.C-1 contains data for the monitors identified 
as remaining nonattainment receptors in 2017 in the CSAPR Update and 
Table III.C-2 contains data for the monitors identified as remaining 
maintenance-only receptors in 2017 in the CSAPR Update.\102\ The design 
values for all monitoring sites in the contiguous U.S. are provided in 
the docket. According to the EPA's findings, there are no remaining 
nonattainment or maintenance receptors in the eastern U.S. in 2023.
---------------------------------------------------------------------------

    \102\ The EPA recognizes that the modeling results indicate a 
substantial projected improvement in ozone air quality (compared to 
current measured ozone levels) at several locations, including three 
monitors in Connecticut located near the sea--i.e., on the order of 
10-12 ppb.
---------------------------------------------------------------------------

    The EPA solicits public comment on the reliability of the modeling 
data, including any information which may support or not support these 
results.\103\ \104\
---------------------------------------------------------------------------

    \103\ From 40 CFR 50.15(b): ``The 8-hour primary and secondary 
ambient air quality standards are met at an ambient air quality 
monitoring site when the 3-year average of the annual fourth-highest 
daily maximum 8-hour average O3 concentration is less 
than or equal to 0.075 ppm, as determined in accordance with 
appendix P to this part.''
    \104\ From section 2.2 of appendix P to 40 CFR part 50: ``The 
computed 3-year average of the annual fourth-highest daily maximum 
8-hour average O3 concentrations shall be reported to 
three decimal places (the digits to the right of the third decimal 
place are truncated, consistent with the data handling procedures 
for the reported data).''

 Table III.C-1--Base Period, Current (2014-2016), and 2023 Projected Design Values (ppb) for Monitors Identified as Remaining Nonattainment Receptors in
                                                            2017 in the CSAPR Update 103 104
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                      2023en     2023en
                                                                             2009-2013  2009-2013               2023en     2023en      ``No       ``No
           Monitor ID                     State                County            Avg        Max    2014-2016  ``3 x 3''  ``3 x 3''   Water''    Water''
                                                                                                                  Avg        Max       Avg        Max
--------------------------------------------------------------------------------------------------------------------------------------------------------
090019003.......................  Connecticut.........  Fairfield..........       83.7         87         85       72.7       75.6       73.0       75.9
090099002.......................  Connecticut.........  New Haven..........       85.7         89         76       71.2       73.9       69.9       72.6
480391004.......................  Texas...............  Brazoria...........       88.0         89         75       74.0       74.9       74.0       74.9
484392003.......................  Texas...............  Tarrant............       87.3         90         73       72.5       74.8       72.5       74.8
484393009.......................  Texas...............  Tarrant............       86.0         86         75       70.6       70.6       70.6       70.6
551170006.......................  Wisconsin...........  Sheboygan..........       84.3         87         79       70.8       73.1       72.8       75.1
--------------------------------------------------------------------------------------------------------------------------------------------------------


 Table III.C-2--Base Period, Current (2014-2016), and 2023 Projected Design Values (ppb) for Monitors Identified as Remaining Maintenance-Only Receptors
                                                               in 2017 in the CSAPR Update
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                      2023en     2023en
                                                                             2009-2013  2009-2013               2023en     2023en      ``No       ``No
           Monitor ID                     State                County            Avg        Max    2014-2016  ``3 x 3''  ``3 x 3''   Water''    Water''
                                                                                                                  Avg        Max       Avg        Max
--------------------------------------------------------------------------------------------------------------------------------------------------------
090010017.......................  Connecticut.........  Fairfield..........       80.3         83         80       69.8       72.1       68.9       71.2
090013007.......................  Connecticut.........  Fairfield..........       84.3         89         81       71.2       75.2       71.0       75.0
240251001.......................  Maryland............  Harford............       90.0         93         73       71.4       73.8       70.9       73.3
260050003.......................  Michigan............  Allegan............       82.7         86         75       69.0       71.8       69.0       71.7
360850067.......................  New York............  Richmond...........       81.3         83         76       71.9       73.4       67.1       68.5
361030002.......................  New York............  Suffolk............       83.3         85         72       72.5       74.0       74.0       75.5
481210034.......................  Texas...............  Denton.............       84.3         87         80       69.7       72.0       69.7       72.0
482010024.......................  Texas...............  Harris.............       80.3         83         79       70.4       72.8       70.4       72.8
482011034.......................  Texas...............  Harris.............       81.0         82         73       70.8       71.6       70.8       71.6
482011039.......................  Texas...............  Harris.............       82.0         84         67       71.8       73.6       71.8       73.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

5. Pollutant Transport From Upwind States
    Although the EPA has conducted nationwide contribution modeling for 
2023, the EPA does not believe this information is necessary for 
evaluating remaining good neighbor obligations for the 2008 ozone NAAQS 
downwind because there are no ozone monitoring sites in the Eastern 
U.S. that are expected to have problems attaining or maintaining the 
2008 ozone NAAQS in 2023. Nonetheless, the results of EPA's state-by-
state ozone contribution modeling were released in a memorandum on 
March 27, 2018 and are also available in the docket for this

[[Page 31937]]

action.\105\ The EPA notes that, while the air quality modeling did 
identify potential remaining problem receptors in California in 2023, 
none of EPA's prior analysis nor its current contribution modeling have 
linked any of the CSAPR Update states in the eastern U.S. to any of 
those potential remaining problem receptors. Therefore, the EPA does 
not believe there is a need to further evaluate the contributions of 
the 20 CSAPR Update states to any downwind receptors identified in 
EPA's 2017 modeling conducted for the CSAPR Update.
---------------------------------------------------------------------------

    \105\ Information on the Interstate Transport State 
Implementation Plan Submissions for the 2015 Ozone National Ambient 
Air Quality Standards under Clean Air Act Section 
110(a)(2)(D)(i)(I). EPA Memorandum to Regional Air Division 
Directors. March 27, 2018. Available at https://www.epa.gov/sites/production/files/2018-03/documents/transport_memo_03_27_18_1.pdf.
---------------------------------------------------------------------------

D. Proposed Determination

    The EPA proposes to determine that, with CSAPR Update 
implementation, 20 eastern states' good neighbor obligations for the 
2008 ozone NAAQS are fully addressed.\106\ The states covered by this 
action are listed in table III.D-1. The EPA's proposed determination is 
based on proposed findings that: (1) 2023 is a reasonable future 
analytic year for evaluating ozone transport problems with respect to 
the 2008 ozone NAAQS; and (2) that interstate ozone transport air 
quality modeling projections for 2023 indicate that no further air 
quality problems will remain in the east in 2023.
---------------------------------------------------------------------------

    \106\ See Table III.D-1 for a list of states covered by this 
proposal. EPA has also already separately proposed to approve 
Kentucky's draft SIP submittal demonstrating that the CSAPR Update 
is a full remedy for Kentucky's good neighbor obligation for the 
2008 ozone NAAQS. 83 FR 17123 (Apr. 18, 2018).
---------------------------------------------------------------------------

    As a result, the EPA proposes to conclude that, after 
implementation of the CSAPR Update, none of the states analyzed will 
significantly contribute to nonattainment or interfere with maintenance 
of the 2008 ozone NAAQS in downwind states, and therefore that the 
CSAPR update fully addresses those states' good neighbor obligations 
with respect to that NAAQS. In accord with this determination, the EPA 
has no remaining obligation issue FIPs nor are states required to 
submit SIPs that would establish additional requirements for sources in 
these states to further reduce transported ozone pollution with regard 
to the 2008 ozone NAAQS.
    As explained in more detail in section III.B, the EPA's selection 
of 2023 as a reasonable future analytic year is supported by an 
assessment of attainment dates for the 2008 ozone NAAQS and feasibility 
for control strategies to reduce NOX in CSAPR Update states. 
The EPA's NOX control strategy feasibility assessment 
prioritizes NOX control strategies in CSAPR Update states 
that would be additional to those strategies that were already 
quantified into CSAPR Update emissions budgets. The EPA believes that 
2023 is an appropriate future analytic year, taking into consideration 
relevant attainment dates, because it is the first ozone season for 
which significant new controls to reduce NOX could be 
feasibly installed across the CSAPR Update region, and thus represents 
the timeframe that is as expeditious as practicable for upwind states 
to implement additional emissions reductions. Furthermore, as described 
in section III.C, the EPA's analysis of step 1 for the 2023 analytic 
year indicates that there are no monitoring sites in the east that are 
projected to have nonattainment or maintenance problems with respect to 
the 2008 ozone NAAQS in 2023. Together, these findings lead to EPA's 
proposed determination that--with CSAPR Update implementation--CSAPR 
Update states are not expected to significantly contribute to 
nonattainment or interfere with maintenance of the 2008 ozone NAAQS in 
downwind states in 2023.
    As a result of this proposed determination, the EPA proposes to 
find that the promulgation of the CSAPR Update for these states fully 
satisfies the requirements of the good neighbor provision for the 2008 
ozone NAAQS, and therefore also satisfies the Agency's obligation 
pursuant to CAA section 110(c) for these states. Accordingly, the EPA 
would have no remaining obligation to issue FIPs nor are the states 
required to submit SIPs that would further reduce transported ozone 
pollution, beyond the existing CSAPR Update requirements, with regard 
to the 2008 ozone NAAQS.

  Table III.D-1--States Covered by the Proposed Determination Regarding
           Good Neighbor Obligations for the 2008 Ozone NAAQS
------------------------------------------------------------------------
                               State name
-------------------------------------------------------------------------
Alabama.
Arkansas.
Illinois.
Indiana.
Iowa.
Kansas.
Louisiana.
Maryland.
Michigan.
Mississippi.
Missouri.
New Jersey.
New York.
Ohio.
Oklahoma.
Pennsylvania.
Texas.
Virginia.
West Virginia.
Wisconsin.
------------------------------------------------------------------------

    Consistent with this proposed determination, this action also 
proposes minor revisions to the existing state-specific sections of the 
CSAPR Update regulations for states other than Kentucky and Tennessee. 
The revisions will remove the current statements indicating that the 
CSAPR Update FIP for each such state only partially addresses the 
state's good neighbor obligation under CAA section 110(a)(2)(D)(i)(I) 
for the 2008 ozone NAAQS. Because states can replace the CSAPR Update 
FIPs with SIPs, these revisions will also mean that a SIP that is 
approved through notice-and-comment rulemaking to fully replace the 
CSAPR Update FIP for one of these states would also fully address the 
state's good neighbor obligation for this NAAQS. In particular, the EPA 
proposes to find that the Agency's previous approval of Alabama's CSAPR 
Update SIP fully satisfies the state's good neighbor obligation for the 
2008 ozone NAAQS. Thus, Alabama would have no obligation to submit any 
additional SIP revision addressing this obligation.
    The EPA seeks comments on this proposal, including the legal, 
technical, and policy decisions informing the EPA's proposed 
determination that the CSAPR Update fully addresses the good neighbor 
obligation with respect to the 2008 ozone NAAQS for 20 eastern states. 
Note that the EPA in this proposal is not reconsidering or reopening 
the determinations made in the CSAPR Update, which was finalized in 
2016, regarding the obligations of upwind states pursuant to the good 
neighbor provision for the 2008 ozone NAAQS. Those determinations have 
already been subject to notice and comment rulemaking processes, and 
the FIPs promulgated in that action are already being implemented. The 
analysis conducted in this action does not reconsider any analysis 
conducted or determinations made in that action.

[[Page 31938]]

Thus, the EPA is not requesting comment on any of the legal, technical, 
or policy decisions informing that the CSAPR Update.

IV. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review, and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is a significant regulatory action that was submitted 
to the Office of Management and Budget (OMB) for review. Any changes 
made in response to OMB recommendations have been documented in the 
docket.

B. Executive Order 13771: Reducing Regulations and Controlling 
Regulatory Costs

    This action is not expected to be subject to Executive Order 13771 
because this proposed rule is expected to result in no more than de 
minimis costs.

C. Paperwork Reduction Act

    This action does not impose any new information collection burden 
under the Paperwork Reduction Act. The OMB has previously approved the 
information collection activities contained in the existing regulations 
and has assigned OMB control number 2060-0667. The minor revisions to 
the FIP provisions proposed in this action would have no impact on 
monitoring, recordkeeping, and reporting requirements for affected EGUs 
in the CSAPR NOX Ozone Season Group 2 Trading Program.

D. Regulatory Flexibility Act

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the Regulatory 
Flexibility Act. In making this determination, the impact of concern is 
any significant adverse economic impact on small entities. An agency 
may certify that a rule will not have a significant economic impact on 
a substantial number of small entities if the rule relieves regulatory 
burden, has no net burden, or otherwise has a positive economic effect 
on the small entities subject to the rule. This action makes a minor 
modification to existing CSAPR Update FIPs and does not impose new 
requirements on any entity. The EPA has therefore concluded that this 
action will have no net regulatory burden for all directly regulated 
small entities.

E. Unfunded Mandates Reform Act

    This action does not contain any unfunded mandate as described in 
the Unfunded Mandates Reform Act, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. The action imposes 
no enforceable duty on any state, local, or tribal governments or the 
private sector. This action simply updates the existing CSAPR Update 
FIPs to establish that no further federal regulatory requirements are 
necessary.

F. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government. This 
action simply updates the existing CSAPR Update FIPs to establish that 
no further federal regulatory requirements are necessary.

G. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications as specified in 
Executive Order 13175. It will not have substantial direct effects on 
tribal governments, on the relationship between the federal government 
and Indian tribes, or on the distribution of power and responsibilities 
between the federal government and Indian tribes. This action simply 
updates the existing CSAPR Update FIPs to establish that no further 
federal regulatory requirements are necessary. Thus, Executive Order 
13175 does not apply to this action. Consistent with the EPA Policy on 
Consultation and Coordination with Indian Tribes, the EPA consulted 
with tribal officials while developing the CSAPR Update. A summary of 
that consultation is provided in the preamble for the CSAPR Update, 81 
FR 74584 (October 26, 2016).

H. Executive Order 13045: Protection of Children From Environmental 
Health and Safety Risks

    The EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. This action is not subject to 
Executive Order 13045 because it simply updates the existing CSAPR 
Update FIPs to establish that no further federal regulatory 
requirements are necessary.

I. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. This action simply updates the existing 
CSAPR Update FIPs to establish that no further federal regulatory 
requirements are necessary.

J. National Technology Transfer Advancement Act

    This rulemaking does not involve technical standards.

K. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    The EPA believes that this action is not subject to Executive Order 
12898 because it does not establish an environmental health or safety 
standard. This action simply updates the existing CSAPR Update FIPs to 
establish that no further federal regulatory requirements are 
necessary. Consistent with Executive Order 12898 and the EPA's 
environmental justice policies, the EPA considered effects on low-
income populations, minority populations, and indigenous peoples while 
developing the CSAPR Update. The process and results of that 
consideration are described in the preamble for the CSAPR Update, 81 FR 
74585 (October 26, 2016).

L. Determinations Under Section 307(b)(1) and (d)

    Section 307(b)(1) of the CAA indicates which Federal Courts of 
Appeal have venue for petitions of review of final actions by EPA. This 
section provides, in part, that petitions for review must be filed in 
the Court of Appeals for the District of Columbia Circuit if (i) the 
agency action consists of ``nationally applicable regulations 
promulgated, or final action taken, by the Administrator,'' or (ii) 
such action is locally or regionally applicable, but ``such action is 
based on a determination of nationwide scope or effect and if in taking 
such action the Administrator finds and publishes that such action is 
based on such a determination.''
    The EPA proposes to find that any final action related to this 
rulemaking is ``nationally applicable'' or, in the alternative, is 
based on a determination of ``nationwide scope and effect'' within the 
meaning of section 307(b)(1).

[[Page 31939]]

Through this rulemaking action, the EPA is interpreting section 110 of 
the CAA, a statutory provision that applies to all states and 
territories in the United States. In addition, the proposed rule 
addresses emissions impacts and sources located in 20 States, which are 
located in multiple EPA Regions and federal circuits. The proposed rule 
is also based on a common core of factual findings and analyses 
concerning the transport of pollutants between the different states. 
Courts have found similar actions to be nationally applicable.\107\ 
Furthermore, EPA intends this interpretation and approach to be 
consistently implemented nationwide with respect to section 
110(a)(2)(D)(i)(I) for the 2008 ozone NAAQS.
---------------------------------------------------------------------------

    \107\ See, e.g., Texas v. EPA, 2011 U.S. App. LEXIS 5654 (5th 
Cir. 2011) (finding SIP call to 13 states to be nationally 
applicable and thus transferring the case to the U.S. Court of 
Appeals for the D.C. Circuit in accordance with CAA section 
307(b)(1)); W. Va. Chamber of Commerce v. Browner, No. 98 1013, 1998 
U.S. App. LEXIS 30621, at *24 (4th Cir. 1998) (finding the 
NOX SIP Call to be nationally applicable based on ``the 
nationwide scope and interdependent nature of the problem, the large 
number of states, spanning most of the country, being regulated, the 
common core of knowledge and analysis involved in formulating the 
rule, and the common legal interpretation advanced of section 110 of 
the Clean Air Act''). Cf. Judgment, Cedar Falls Utilities v. EPA, 
No. 16-4504 (8th Cir. Feb. 22, 2017) (transferring petition to 
review CSAPR Update to D.C. Circuit).
---------------------------------------------------------------------------

    For these reasons, the Administrator proposes to determine that any 
final action related to this proposal is nationally applicable or, in 
the alternative, is based on a determination of nationwide scope and 
effect for purposes of section 307(b)(1). Thus, pursuant to section 
307(b) any petitions for review of any final actions regarding the 
rulemaking must be filed in the Court of Appeals for the District of 
Columbia Circuit within 60 days from the date any final action is 
published in the Federal Register.
    In addition, pursuant to sections 307(d)(1)(C) and 307(d)(1)(V) of 
the CAA, the Administrator proposes to determine that this action is 
subject to the provisions of section 307(d). CAA section 307(d)(1)(B) 
provides that section 307(d) applies to, among other things, ``the 
promulgation or revision of an implementation plan by the Administrator 
under CAA section 110(c).'' 42 U.S.C. 7407(d)(1)(B). Under section 
307(d)(1)(V), the provisions of section 307(d) also apply to ``such 
other actions as the Administrator may determine.'' 42 U.S.C. 
7407(d)(1)(V). The Agency has complied with procedural requirements of 
CAA section 307(d) during the course of this rulemaking.

List of Subjects in 40 CFR Part 52

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Incorporation by reference, Intergovernmental 
relations, Nitrogen oxides, Ozone, Particulate matter, Regional haze, 
Reporting and recordkeeping requirements, Sulfur dioxide.

    Dated: June 29, 2018.
E. Scott Pruitt,
Administrator.

    For the reasons stated in the preamble, part 52 of chapter I of 
title 40 of the Code of Federal Regulations is proposed to be amended 
as follows:

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.


Sec. Sec.  52.54, 52.184, 52.731, 52.789, 52.840, 52.882, 52.984, 
52.1084, 52.1186, 52.1284, 52.1326, 52.1584, 52.1684, 52.1882, 52.1930, 
52.2040, 52.2283, 52.2440, 52.2540, and 52.2587   [Amended]

0
2. In 40 CFR part 52 remove the text ``, provided that because the 
CSAPR FIP was promulgated as a partial rather than full remedy for an 
obligation of the State to address interstate air pollution, the SIP 
revision likewise will constitute a partial rather than full remedy for 
the State's obligation unless provided otherwise in the Administrator's 
approval of the SIP revision'' from the second sentence in each of the 
following paragraphs:
0
a. Section 52.54(b)(2);
0
b. Section 52.184(b);
0
c. Section 52.731(b)(2);
0
d. Section 52.789(b)(2);
0
e. Section 52.840(b)(2);
0
f. Section 52.882(b)(1);
0
g. Section 52.984(d)(2);
0
h. Section 52.1084(b)(2);
0
i. Section 52.1186(e)(2);
0
j. Section 52.1284(b);
0
k. Section 52.1326(b)(2);
0
l. Section 52.1584(e)(2);
0
m. Section 52.1684(b)(2);
0
n. Section 52.1882(b)(2);
0
o. Section 52.1930(b);
0
p. Section 52.2040(b)(2);
0
q. Section 52.2283(d)(2);
0
r. Section 52.2440(b)(2);
0
s. Section 52.2540(b)(2); and
0
t. Section 52.2587(e)(2).

[FR Doc. 2018-14737 Filed 7-9-18; 8:45 am]
 BILLING CODE 6560-50-P