
[Federal Register Volume 84, Number 46 (Friday, March 8, 2019)]
[Rules and Regulations]
[Pages 8422-8443]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-03854]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 51 and 52

[EPA-HQ-OAR-2018-0595; FRL-9990-33-OAR]
RIN 2060-AU08


Emissions Monitoring Provisions in State Implementation Plans 
Required Under the NOX SIP Call

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is revising some of 
the regulations that were originally promulgated in 1998 to implement 
the NOX SIP Call. The revisions give covered states greater 
flexibility concerning the form of the nitrogen oxides (NOX) 
emissions monitoring requirements that the states must include in their 
state implementation plans (SIPs) for certain emissions sources. Other 
revisions remove obsolete provisions and clarify the remaining 
regulations but do not substantively alter any current regulatory 
requirements.

DATES: This rule is effective as of March 8, 2019.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-HQ-OAR-2018-0595. All documents in the docket are listed on the 
http://www.regulations.gov website. Although listed in the index, some 
information is not publicly available, e.g., confidential business 
information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only in hard 
copy form. Publicly available docket materials are available 
electronically through http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: David Lifland, Clean Air Markets 
Division, Office of Atmospheric Programs, U.S. Environmental Protection 
Agency, MC 6204M, 1200 Pennsylvania Avenue NW, Washington, DC 20460; 
202-343-9151; lifland.david@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Overview of the Action
    A. Summary of Amendments and Estimated Impacts
    B. Potentially Affected Entities
    C. Statutory Authority
II. Summary of the Proposal
    A. Background
    B. Proposed Amendment to Emissions Monitoring Requirements
    C. Other Proposed Amendments
    D. Public Comment Process
III. Response to Comments
    A. Emissions Monitoring Requirements
    B. Emissions Reduction Requirements
    C. Baseline Emissions Inventory Table
    D. Post-NBTP Transition Requirements
IV. Final Action
V. Impacts of the Amendments
VI. Statutory 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
    H. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks

[[Page 8423]]

    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. Congressional Review Act
    M. Determinations Under CAA Section 307(b) and (d)

I. Overview of the Action

    This section provides an overview of the action, including a 
summary of the amendments and their estimated impacts as well as 
information concerning potentially affected entities and statutory 
authority.
    Section II provides a summary of the proposal for this action, 
including background information. In section III, EPA summarizes and 
responds to comments received on the proposal. EPA's final action is 
set forth in section IV, and section V discusses the estimated impacts 
of the amendments. Section VI addresses reviews required under various 
statutes and executive orders as well as determinations concerning 
applicable rulemaking and judicial review provisions.

A. Summary of Amendments and Estimated Impacts

    On September 27, 2018, EPA published in the Federal Register a 
proposal \1\ to amend the existing NOX SIP Call regulations 
\2\ to allow states to amend their SIPs, for NOX SIP Call 
purposes only, to establish emissions monitoring requirements for 
certain units other than requirements to monitor according to 40 CFR 
part 75. This action finalizes the amendment generally as proposed, 
with minor further revisions discussed in section IV of this document. 
Ultimately, such alternate monitoring requirements could be made 
available to sources through states' revisions to their SIPs, with 
consequent potential reductions in some units' monitoring costs. The 
group of units affected under the SIPs adopted to meet the 
NOX SIP Call comprises both existing and new electricity 
generating units (EGUs) as well as certain other existing and new 
industrial units (non-EGUs). Within this overall group, the set of 
existing units potentially affected by the amendment includes 
approximately 285 non-EGU boilers and combustion turbines and 
approximately 30 EGUs--specifically, combustion turbines that are 
considered large EGUs for NOX SIP Call purposes and that are 
not required to monitor according to part 75 under other programs such 
as the Acid Rain Program or a Cross-State Air Pollution Rule (CSAPR) 
trading program. States, not EPA, will decide whether to revise the 
monitoring requirements in their SIPs as allowed under this amendment, 
and EPA lacks complete information on the remaining monitoring 
requirements that the sources would face if a state decides to make 
such revisions, leaving considerable uncertainty regarding the amount 
of monitoring cost reductions that may occur. However, using 
information from comments and assumptions concerning the sources' 
remaining monitoring requirements, EPA estimates annual monitoring cost 
reductions from this action in the range of $1.2 million to $3.3 
million. Because this action is not expected to cause any change in 
emissions or air quality, the monitoring cost reductions will 
constitute net benefits from the action.
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    \1\ Emissions Monitoring Provisions in State Implementation 
Plans Required Under the NOX SIP Call, Proposed Rule, 83 
FR 48751 (Sept. 27, 2018).
    \2\ Finding of Significant Contribution and Rulemaking for 
Certain States in the Ozone Transport Assessment Group Region for 
Purposes of Reducing Regional Transport of Ozone (NOX SIP 
Call), 63 FR 57356 (Oct. 27, 1998) (codified in relevant part at 40 
CFR 51.121 and 51.122). Amendments to the NOX SIP Call 
regulations made between issuance and implementation are described 
in the proposal for this action, 83 FR at 48755 & nn.11-15.
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    In addition, EPA is eliminating several obsolete provisions of the 
NOX SIP Call regulations that no longer have any substantive 
effect on the regulatory requirements faced by states or sources and is 
making clarifying amendments--all of which EPA considers non-
substantive--to the remaining regulations. The additional amendments 
also include updates to several cross-references in the CSAPR 
regulations that refer to an obsolete provision of the NOX 
SIP Call regulations. The specific additional amendments discussed in 
the proposal are identified in section II.C. of this document, and the 
amendments are being finalized generally as proposed, with minor 
further revisions discussed in section IV of this document.

B. Potentially Affected Entities

    This action does not apply directly to any emissions sources but 
instead amends existing regulatory requirements applicable to the SIPs 
of Alabama, Connecticut, Delaware, Illinois, Indiana, Kentucky, 
Maryland, Massachusetts, Michigan, Missouri, New Jersey, New York, 
North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, 
Tennessee, Virginia, West Virginia, and the District of Columbia. If an 
affected jurisdiction chooses to revise its SIP in response to these 
amendments, sources in the jurisdiction could be indirectly affected if 
they are subject to emissions monitoring requirements for purposes of 
the NOX SIP Call and are not independently subject to 
comparable requirements under another program such as the Acid Rain 
Program or a CSAPR trading program. Generally, the types of sources 
that could be indirectly affected are fossil fuel-fired boilers and 
stationary combustion turbines with heat input capacities over 250 
million British thermal units per hour (mmBtu/hr) or serving 
electricity generators with capacities over 25 megawatts (MW). Sources 
meeting these criteria operate in a variety of industries, including 
but not limited to the following:

------------------------------------------------------------------------
                                        Examples of industries with
           NAICS * code                 potentially affected sources
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221112...........................  Fossil fuel-fired electric power
                                    generation.
3112.............................  Grain and oilseed milling.
3221.............................  Pulp, paper, and paperboard mills.
3241.............................  Petroleum and coal products
                                    manufacturing.
3251.............................  Basic chemical manufacturing.
3311.............................  Iron and steel mills and ferroalloy
                                    manufacturing.
6113.............................  Colleges, universities, and
                                    professional schools.
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* North American Industry Classification System.

C. Statutory Authority

    Statutory authority for this action is provided by Clean Air Act 
(CAA) sections 110 and 301, 42 U.S.C. 7410 and 7601, which also 
provided statutory authority for issuance of the existing 
NOX SIP Call regulations that EPA is amending in this 
action.\3\
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    \3\ See, e.g., 63 FR at 57366, 57479.
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II. Summary of the Proposal

    This section summarizes the proposal for this action. Section II.A. 
repeats some of the background information from the proposal. Section 
II.B. addresses the proposed amendment to the NOX SIP Call's 
emissions monitoring requirements, reiterating the proposed rationale 
and summarizing the proposal's discussion of projected impacts. 
Sections II.C. and II.D. summarize the remaining proposed amendments 
and describe the public comment process.

A. Background

    Under the CAA, EPA establishes and periodically revises national 
ambient air quality standards (NAAQS) for certain pollutants, including 
ground-level ozone, while states have primary responsibility for 
attaining the NAAQS through the adoption of emission control measures 
in their SIPs. Under CAA section 110(a)(2)(D)(i)(I), 42 U.S.C. 
7410(a)(2)(D)(i)(I), often called the ``good neighbor'' provision, each 
state is

[[Page 8424]]

required to include provisions in its SIP prohibiting emissions that 
``will . . . contribute significantly to nonattainment in, or interfere 
with maintenance by, any other State with respect to any [NAAQS].'' In 
1998, EPA issued the NOX SIP Call (the Rule) identifying 
good neighbor obligations with respect to the 1979 1-hour ozone NAAQS 
and calling for SIP revisions to address those obligations.\4\ The 
Rule's regulatory text was codified at 40 CFR 51.121, addressing the 
required SIP revisions, and 40 CFR 51.122, addressing states' periodic 
reporting requirements. As implemented, the Rule required 20 states and 
the District of Columbia \5\ to revise their SIPs to reduce their 
sources' emissions of NOX, an ozone precursor, during the 
May-September ``ozone season'' starting in 2004.
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    \4\ 63 FR 57356. As described in the proposal for this action, 
an amendment to the NOX SIP Call made before the Rule's 
implementation indefinitely stayed the additional findings of good 
neighbor obligations with respect to the 1997 8-hour ozone NAAQS 
that were included in the Rule as issued. See 83 FR at 48755.
    \5\ The Rule as implemented applies to Connecticut, Delaware, 
Illinois, Indiana, Kentucky, Maryland, Massachusetts, New Jersey, 
New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South 
Carolina, Tennessee, Virginia, and West Virginia; portions of 
Alabama, Michigan, and Missouri; and the District of Columbia. For 
simplicity, this document often refers to all the jurisdictions with 
obligations under the CAA and the NOX SIP Call, including 
the District of Columbia, as ``states.''
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    To implement the NOX SIP Call's emissions reduction 
requirements, EPA promulgated a ``budget'' for the statewide seasonal 
NOX emissions from each covered state. Each state's 
emissions budget was calculated as the state's projected 2007 pre-
control or ``baseline'' emissions inventory minus the state's required 
emissions reduction. The Rule did not mandate that states follow any 
particular approach for achieving their required emissions reductions. 
Instead, states retained wide discretion regarding which sources in 
their states to control and what control measures to employ. Each state 
was simply required to demonstrate that whatever control measures it 
chose to include in its SIP revision would be sufficient to ensure that 
projected 2007 statewide seasonal NOX emissions from its 
sources would not exceed its emissions budget.
    Besides the general flexibility given to states regarding the 
choices of sources and control measures, the NOX SIP Call 
included additional provisions designed to increase compliance 
flexibility. Most notably, the Rule allowed states to adopt interstate 
emission allowance trading programs as control measures to accomplish 
some or all of the required emissions reductions. EPA also provided a 
model rule for an EPA-administered interstate trading program--the 
NOX Budget Trading Program (NBTP)--that would meet all the 
Rule's SIP approval criteria for a trading program for two types of 
sources: Fossil fuel-fired EGU boilers and combustion turbines serving 
electricity generators with capacity ratings greater than 25 MW (large 
EGUs), and fossil fuel-fired non-EGU boilers and combustion turbines 
with heat input ratings greater than 250 mmBtu/hr (large non-EGU 
boilers and turbines).
    While generally oriented toward providing states and sources with 
compliance flexibility, the NOX SIP Call also included two 
conditional provisions that would become mandatory SIP requirements for 
large EGUs and large non-EGU boilers and turbines if states chose to 
include any emission control measures for these types of sources in 
their SIP revisions. First, under Sec.  51.121(f)(2), any control 
measures imposed on these types of sources would be required to include 
enforceable limits on the sources' seasonal NOX mass 
emissions. These limits could take several forms, including either 
limits on individual sources or collective limits on the group of all 
such sources in a state. Second, under Sec.  51.121(i)(4), these 
sources would be required to monitor and report their seasonal 
NOX mass emissions according to the provisions of 40 CFR 
part 75.\6\ One way a state could meet these two SIP requirements was 
to adopt the NBTP, because the NBTP included provisions addressing both 
requirements and was expressly designed as a potential control measure 
for these types of sources.
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    \6\ For brevity, this document generally refers to the 
monitoring, recordkeeping, and reporting requirements in 40 CFR part 
75 as ``part 75 monitoring requirements.''
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    All the jurisdictions subject to the NOX SIP Call as 
implemented ultimately chose to adopt the NBTP for large EGUs and large 
non-EGU boilers and turbines as part of their required SIP revisions. 
By adopting control measures applicable to large EGUs and large non-EGU 
boilers and turbines into their SIPs, all the affected jurisdictions 
triggered the obligations for their SIPs to include enforceable mass 
emissions limits and part 75 monitoring requirements for these types of 
sources. These requirements have remained in effect despite the 
discontinuation of the NBTP following the 2008 ozone season.\7\
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    \7\ Some states expanded NBTP applicability under their SIPs to 
include additional sources such as process heaters, cement kilns, 
and smaller EGUs. Unlike large EGUs and large non-EGU boilers and 
turbines, the additional sources are not subject to the 
NOX SIP Call's ongoing obligation under Sec.  
51.121(i)(4) for SIPs to include part 75 monitoring requirements and 
therefore are not affected by the amendments being finalized in this 
action.
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    The NBTP was implemented starting in 2003 for sources in several 
northeastern states and in 2004 for sources in most of the remaining 
NOX SIP Call states. Missouri sources joined the NBTP in 
2007, and EPA continued to administer the NBTP through the 2008 ozone 
season. Since the 2008 ozone season, EPA has replaced the NBTP with a 
series of three similar interstate emission allowance trading programs 
designed to address eastern states' good neighbor obligations with 
respect to ozone NAAQS more recent than the 1979 1-hour ozone NAAQS. 
The NBTP's three successor seasonal NOX trading programs 
were established under the Clean Air Interstate Rule (CAIR),\8\ which 
was remanded to EPA for replacement; \9\ the original CSAPR,\10\ which 
replaced CAIR; and most recently the CSAPR Update.\11\ The seasonal 
NOX trading programs established under CAIR and the original 
CSAPR were both designed to address the 1997 8-hour ozone NAAQS, while 
the trading program established under the CSAPR Update was designed to 
address the 2008 8-hour ozone NAAQS. The CAIR seasonal NOX 
trading program operated from 2009 through 2014, the original CSAPR 
seasonal NOX trading program started operating in 2015,\12\ 
and the CSAPR Update trading program started operating in 2017.
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    \8\ 70 FR 25162 (May 12, 2005) (SIP requirements); 71 FR 25328 
(Apr. 28, 2006) (parallel Federal implementation plan requirements).
    \9\ North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008), 
modified on rehearing, 550 F.3d 1176 (D.C. Cir. 2008).
    \10\ 76 FR 48208 (Aug. 8, 2011); see also 76 FR 80760 (Dec. 27, 
2011) (adding seasonal NOX emissions reduction 
requirements for sources in five states), 79 FR 71663 (Dec. 3, 2014) 
(tolling implementation dates by three years).
    \11\ 81 FR 74504 (Oct. 26, 2016). Consolidated challenges to the 
CSAPR Update are pending in Wisconsin v. EPA, No. 16-1406 (D.C. Cir. 
argued Oct. 3, 2018).
    \12\ The original CSAPR seasonal NOX trading program 
remains in effect for sources in Georgia but after 2016 has not 
applied to sources in any state subject to the NOX SIP 
Call as implemented.
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    For purposes of this action, the most important difference between 
the NBTP and its successor seasonal NOX trading programs 
concerns the types of sources participating in the various programs. As 
discussed above, the NBTP was designed to cover both large EGUs and 
large non-EGU boilers and turbines. In contrast, by default the three 
successor trading programs have covered only units considered EGUs 
under those

[[Page 8425]]

programs, which generally means all units that would be classified as 
NOX SIP Call large EGUs as well as a small subset of the 
units that would be classified as NOX SIP Call large non-EGU 
boilers and turbines.\13\ Under the CAIR seasonal NOX 
trading program, most NOX SIP Call states exercised an 
option to expand program applicability to include all their 
NOX SIP Call large non-EGU boilers and turbines, but the 
option was eliminated under the original CSAPR seasonal NOX 
trading program and no state has exercised the restored option made 
available under the CSAPR Update trading program. Consequently, at 
present most NOX SIP Call large non-EGU boilers and turbines 
do not participate in a successor trading program to the NBTP.
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    \13\ For example, under the NOX SIP Call as 
implemented, a unit qualifying as exempt from the Acid Rain Program 
under the provision for cogeneration units at 40 CFR 72.6(b)(4) 
would be classified as a non-EGU, but in some instances such a unit 
could be covered under the CAIR, original CSAPR, and CSAPR Update 
trading programs as an EGU.
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    The second relevant difference between the NBTP and its successor 
trading programs concerns the various programs' geographic areas of 
coverage. At present, EGUs in fourteen NOX SIP Call states 
participate in the CSAPR Update trading program.\14\ EGUs in the 
remaining seven NOX SIP Call jurisdictions do not currently 
participate in a successor trading program to the NBTP, although most 
such units are subject to other EPA programs with comparable part 75 
monitoring requirements.\15\
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    \14\ The CSAPR Update applies to EGUs in the NOX SIP 
Call states of Alabama, Illinois, Indiana, Kentucky, Maryland, 
Michigan, Missouri, New Jersey, New York, Ohio, Pennsylvania, 
Tennessee, Virginia, and West Virginia as well as eight additional 
states that are not subject to the NOX SIP Call as 
implemented.
    \15\ EGUs in the NOX SIP Call jurisdictions of 
Connecticut, Delaware, Massachusetts, North Carolina, Rhode Island, 
South Carolina, and the District of Columbia are not subject to the 
CSAPR Update. All NOX SIP Call EGUs in North Carolina and 
South Carolina are required to monitor NOX mass emissions 
according to part 75 under a CSAPR trading program for annual 
NOX emissions, and most NOX SIP Call EGUs in 
the remaining jurisdictions are required to monitor NOX 
emission rate and heat input rate according to part 75 under the 
Acid Rain Program.
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    In the CAIR rulemaking, EPA amended the NOX SIP Call 
regulations both to provide that the NBTP would be discontinued upon 
implementation of the CAIR seasonal NOX trading program and 
to require states to adopt replacement control measures into their SIPs 
to ensure continued achievement of the portions of their NOX 
SIP Call emissions reduction requirements that had been met through the 
NBTP.\16\ As noted above, notwithstanding the discontinuation of the 
NBTP, the NOX SIP Call's requirements for enforceable mass 
emissions limits and part 75 monitoring have continued to apply to 
large EGUs and large non-EGU boilers and turbines in all affected 
states. Since the CAIR rulemaking, EPA has worked with NOX 
SIP Call states individually to assist them in revising their SIPs to 
meet these ongoing NOX SIP Call requirements, whether 
through use of the NBTP's successor trading programs (to the extent 
those options have been available) or through other replacement control 
measures.
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    \16\ 40 CFR 51.121(r); see also 40 CFR 51.123(bb) and 
52.38(b)(10)(ii) (authorizing use of CAIR and CSAPR Update seasonal 
NOX trading programs as NBTP replacement control measures 
for large non-EGU boilers and turbines).
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    Under CAA section 107(d)(3)(E), 42 U.S.C. 7407(d)(3)(E), 
redesignation of an area to attainment of a NAAQS requires a 
determination that the improvement in air quality is due to ``permanent 
and enforceable'' emissions reductions. At least 140 EPA final actions 
redesignating areas in 20 states to attainment with an ozone NAAQS or a 
fine particulate matter (PM2.5) NAAQS--because 
NOX is a precursor to PM2.5 as well as ozone--
have relied in part on the NOX SIP Call's emissions 
reductions.\17\ In this action, to avoid any possible argument that 
amendments to the NOX SIP Call might result in a lessening 
of permanence and enforceability that could threaten continued reliance 
on the Rule's emissions reductions to support other actions, EPA is not 
substantively amending the Rule's key provisions supporting these 
attributes. These key provisions include the statewide emissions 
budgets and general enforceability and monitoring requirements as well 
as the requirements for enforceable limits on seasonal NOX 
mass emissions from large EGUs and large non-EGU boilers and 
turbines.\18\ As discussed in section II.B. of this document, EPA 
believes that under current circumstances, the amendment to allow 
states to establish alternate monitoring requirements for large EGUs 
and large non-EGU boilers and turbines does not undermine assurance 
that the Rule's required emissions reductions will continue to be 
achieved and therefore does not pose a risk to the permanence and 
enforceability of the emissions reductions.
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    \17\ See Redesignation Actions Relying on NOX SIP 
Call Emissions Reductions (August 2018), available in the docket for 
this action. EPA notes that reliance on the Rule's emissions 
reductions as permanent and enforceable for purposes of 
redesignation actions has been upheld by multiple courts of appeals. 
Sierra Club v. EPA, 774 F.3d 383, 397-99 (7th Cir. 2014); Sierra 
Club v. EPA, 793 F.3d 656, 665-68 (6th Cir. 2015).
    \18\ EPA notes that the implementation rules for both the 1997 
ozone NAAQS and the 2008 ozone NAAQS have required that the 
NOX SIP Call in general and states' emissions budgets in 
particular will continue to apply after revocation of the previous 
NAAQS and have also made clear that any modifications to control 
requirements approved into a SIP pursuant to the Rule are subject to 
anti-backsliding requirements under CAA section 110(l), 42 U.S.C. 
7410(l). See 40 CFR 51.905(f), 51.1105(e).
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B. Proposed Amendment to Emissions Monitoring Requirements

    The only substantive amendment to the NOX SIP Call 
regulations proposed for this action concerns emissions monitoring 
requirements. Under 40 CFR 51.121(i)(4) of the regulations as 
originally promulgated, where a state's SIP revision contains control 
measures for large EGUs or large non-EGU boilers and turbines, the SIP 
must also require part 75 monitoring for these types of sources. As 
discussed in section II.A. of this document, all NOX SIP 
Call states triggered this requirement by including control measures in 
their SIPs for these types of sources, and the requirement has remained 
in effect despite the discontinuation of the NBTP after the 2008 ozone 
season. For this action, EPA proposed to amend the provision at Sec.  
51.121(i)(4) to make the inclusion of part 75 monitoring requirements 
for these sources in SIPs optional rather than mandatory for 
NOX SIP Call purposes.\19\ The SIPs would still need to 
include some form of emissions monitoring requirements for these types 
of sources, consistent with the Rule's general enforceability and 
monitoring requirements at Sec.  51.121(f)(1) and (i)(1), respectively, 
but states would no longer be required to satisfy these general Rule 
requirements specifically through the adoption of part 75 monitoring 
requirements. EPA noted that finalization of this proposed amendment 
would not in itself eliminate part 75 monitoring requirements for any 
sources but would enable EPA to approve SIP submittals replacing these 
requirements for NOX SIP Call purposes with other forms of 
monitoring requirements.
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    \19\ The amendment would apply only for NOX SIP Call 
purposes and would not authorize states to create exceptions to any 
part 75 monitoring requirements that might apply to a source under a 
different legal authority.
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    In the proposal, EPA discussed the following rationale for the 
proposed amendment to emissions monitoring requirements.\20\ The 
condition that SIPs must include part 75 monitoring requirements was 
established based on

[[Page 8426]]

determinations that, first, a requirement for mass emissions limits for 
large EGUs and large non-EGU boilers and turbines was feasible and 
provided the greatest assurance that the NOX SIP Call's 
required emissions reductions would be achieved, and second, part 75 
monitoring was a feasible and cost-effective way to ensure compliance 
with the mass emissions limits for these sources.\21\ (Part 75 
monitoring requirements were also established independently as an 
essential element of the now-discontinued NBTP, which like EPA's other 
emission allowance trading programs could function only with timely 
reporting of consistent, quality-assured mass emissions data by all 
participating units.) To ensure that the NOX SIP Call's 
emissions reductions can continue to be relied on as permanent and 
enforceable for purposes of other actions, EPA did not propose to amend 
the Rule's existing requirements regarding enforceable mass emissions 
limits for these sources. However, EPA proposed the view that under 
current circumstances, allowing states to establish alternate 
monitoring requirements for large EGUs and large non-EGU boilers and 
turbines would not pose a risk to the permanence and enforceability of 
the Rule's emissions reductions.
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    \20\ 83 FR at 48757-58.
    \21\ See 63 FR at 57451-52.
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    The first relevant current circumstance EPA discussed was the 
substantial margins by which all NOX SIP Call states are now 
complying with the portions of their statewide emissions budgets 
assigned to large EGUs and large non-EGU boilers and turbines. As shown 
in Table 1 of the proposal, which is reproduced without change as Table 
1 of this document, in 2017, seasonal NOX emissions from 
sources that would have been subject to the NBTP across the region 
covered by the NOX SIP Call were approximately 200,000 tons, 
which is less than 40% of the sum of the relevant portions of the 
statewide final NOX budgets. Table 1 also shows that no 
state's reported emissions exceeded 71% of the relevant portion of its 
budget.\22\ As noted by EPA, these comparisons demonstrate that the 
Rule's required emissions reductions would continue to be achieved even 
with substantial increases in emissions from current levels. EPA also 
observed that the possibility of such large increases in emissions is 
remote because of requirements under other state and Federal 
environmental programs \23\ and changes to the fleet of affected 
sources since 2008.\24\
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    \22\ Reported 2017 emissions from Missouri sources were just 
over 70% of the relevant portion of the state's budget.
    \23\ For example, for the 11 states covered in their entirety 
under both programs--Illinois, Indiana, Kentucky, Maryland, New 
Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West 
Virginia--EGU emissions budgets under the current CSAPR Update 
seasonal NOX trading program range from 17% to 66% of the 
portions of the respective states' NOX SIP Call statewide 
budgets based on EGU emissions. Compare 40 CFR 97.810(a) (CSAPR 
Update budgets) with 65 FR 11222, 11225 (Mar. 2, 2000) (EGU-based 
portions of NOX SIP Call statewide budgets).
    \24\ For example, sources responsible for over 40% of 2008 
emissions reported under the NBTP have either ceased operation or 
switched from coal combustion to gas or oil combustion since 2008. 
See Post-2008 Changes to Units Reporting Under the NOX 
Budget Trading Program (August 2018), available in the docket for 
this action.

                     Table 1--2017 Emissions and Relevant Emissions Budget Amounts by State
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                                      NOX emissions during the 2017 ozone season (tons) from:       Portion of
                                 ----------------------------------------------------------------    statewide
                                   NBTP sources     Other NBTP      Other NBTP                       emissions
              State                also subject   large EGUs and      sources                         budget
                                    to part 75     large non-EGU    subject to     Total for all    assigned to
                                    under other     boilers and    part 75 under   NBTP sources    NBTP sources
                                     programs        turbines        NSC SIPs                         (tons)
----------------------------------------------------------------------------------------------------------------
Alabama (part)..................           7,166           1,911               0           9,077          25,497
Connecticut.....................             380              10              39             430           4,477
Delaware........................             324             511               0             835           5,227
District of Columbia............               0              20               0              20             233
Illinois........................          13,038           1,493               0          14,531          35,557
Indiana.........................          20,396           1,201             823          22,419          55,729
Kentucky........................          19,978              75               0          20,053          36,109
Maryland........................           2,422             516               0           2,939          15,466
Massachusetts...................             734             113              32             879          12,861
Michigan (part).................          14,580             205               0          14,785          31,247
Missouri (part).................           9,486               0               0           9,486          13,459
New Jersey......................           1,646             310               0           1,956          13,022
New York........................           4,062             941             611           5,614          41,385
North Carolina..................          16,352           1,689               0          18,041          34,703
Ohio............................          20,012             993               0          21,005          49,842
Pennsylvania....................          13,616             837               0          14,453          50,843
Rhode Island....................             193               0               0             193             936
South Carolina..................           5,030           1,043               0           6,074          19,678
Tennessee.......................           7,785           2,350               0          10,135          31,480
Virginia........................           7,462             589               0           8,051          21,195
West Virginia...................          18,187             276               0          18,463          29,507
                                 -------------------------------------------------------------------------------
    Total.......................         182,849          15,084           1,505         199,438         528,453
----------------------------------------------------------------------------------------------------------------
Data sources: Emissions data are from EPA's Air Markets Program Database, https://ampd.epa.gov/ampd. In a few
  cases where 2017 data are not available, the most recent available data are used instead. Budget data are from
  The NOX Budget Trading Program: 2008 Emission, Compliance, and Market Analyses (July 2009) at 14, available in
  the docket for this action.

    The second relevant current circumstance EPA discussed was that 
even with the proposed amendment, part 75 monitoring requirements would 
remain in effect for most NOX SIP Call large EGUs pursuant 
to other regulatory requirements, including the Acid Rain Program and 
the CSAPR trading programs, and these large EGUs are responsible for 
most of the collective emissions of NOX SIP Call large EGUs 
and large non-EGU boilers and turbines.

[[Page 8427]]

Table 1 shows the portions of the reported seasonal NOX 
emissions for each state reported by units that would continue to be 
subject to part 75 monitoring requirements even if the proposed 
amendments are finalized and all states choose to revise their 
SIPs.\25\ As indicated in the table, the sources that would continue to 
report under part 75 account for over 90% of the overall emissions. If 
a state chooses to revise its SIP to no longer require part 75 
monitoring for some sources, then under Sec.  51.121(f)(1) and (i)(1)--
which EPA did not propose to amend--the SIP would still have to include 
provisions requiring all large EGUs and large non-EGU boilers and 
turbines subject to control measures for purposes of the NOX 
SIP Call to submit other forms of information on their seasonal 
NOX emissions sufficient to ensure compliance with the 
control measures. EPA stated the belief that in the context of the 
substantial compliance margins discussed above, and given the continued 
availability of part 75 monitoring data from sources responsible for 
most of the relevant emissions, emissions data from the remaining 
sources submitted pursuant to other forms of monitoring requirements 
can provide sufficient assurance that the Rule's overall required 
emissions reductions will continue to be achieved.
---------------------------------------------------------------------------

    \25\ Although the Acid Rain Program does not require units to 
report NOX mass emissions specifically, NOX 
mass emissions can be calculated from other part 75 data that are 
required to be reported.
---------------------------------------------------------------------------

    In the proposal's discussion of projected impacts,\26\ EPA stated 
the expectation that the proposed amendments, if finalized, would have 
no impact on emissions or air quality because no changes would be made 
to any of the NOX SIP Call's existing regulatory 
requirements related to statewide emissions budgets or enforceable mass 
emissions limits for large EGUs and large non-EGU boilers and turbines.
---------------------------------------------------------------------------

    \26\ 83 FR at 48761-62.
---------------------------------------------------------------------------

    With respect to cost impacts, EPA expressed the expectation that, 
if the proposed amendment to monitoring requirements is finalized, at 
least some states would revise their SIPs to establish alternate 
monitoring requirements and at least some sources would experience 
reductions in monitoring costs. EPA indicated that there were 
approximately 310 existing large EGUs and large non-EGU boilers and 
turbines in NOX SIP Call states that could potentially be 
affected by the proposed amendment to monitoring requirements if all 
affected states were to revise their SIPs. The discussion also 
indicated how many of these units used each of the principal monitoring 
methodologies allowed under part 75 according to the monitoring plans 
submitted for the units. Specifically, EPA noted that approximately 90 
units used monitoring methodologies involving continuous emissions 
monitoring systems (CEMS) to measure both stack gas flow rate and the 
concentrations of certain gases in the effluent gas stream, 
approximately 140 units used methodologies involving gas concentration 
CEMS but not stack gas flow rate CEMS, and approximately 80 units used 
non-CEMS methodologies. The proposal noted that it was not possible to 
predict the amount of the monitoring cost reductions that might 
eventually result from finalization of the proposed monitoring 
amendment because states, not EPA, would decide whether to revise the 
monitoring requirements in their SIPs and because EPA lacks information 
on the remaining monitoring requirements that sources would face. 
However, EPA qualitatively discussed how alternate monitoring 
requirements could result in reduced costs for units currently using 
the various part 75 monitoring methodologies. For example, some units 
that currently use part 75 monitoring methodologies involving the use 
of stack gas flow rate CEMS might be allowed to discontinue use of 
those CEMS, some units that currently use part 75 monitoring 
methodologies involving the use of gas concentration CEMS might be 
allowed to discontinue use of those CEMS, and some units continuing to 
use one or both types of CEMS might be allowed to perform less 
extensive data reporting or less comprehensive quality-assurance 
testing. EPA expressed the expectation that units currently using non-
CEMS methodologies under part 75 would experience little or no 
reduction in monitoring costs as a result of the proposed monitoring 
amendment.

C. Other Proposed Amendments

    In addition to the proposed amendment to the NOX SIP 
Call's monitoring requirements discussed in section II.B. of this 
document, EPA proposed to make several further amendments to the Rule's 
regulatory text at 40 CFR 51.121 and 51.122 to remove obsolete 
provisions and clarify the remaining provisions. The proposed revisions 
also included updates to several cross-references in the CSAPR 
regulations at 40 CFR 52.38 that refer to an obsolete provision of the 
NOX SIP Call regulations. Although EPA proposed to remove or 
modify numerous provisions of the NOX SIP Call 
regulations,\27\ the proposal explained that the additional amendments 
were not intended to substantively alter any currently effective 
regulatory requirements. Briefly, EPA proposed to:
---------------------------------------------------------------------------

    \27\ A redline-strikeout document showing the text of 40 CFR 
51.121 and 51.122 with the amendments adopted in this action, which 
include all the proposed amendments to the NOX SIP Call 
regulations with the further revisions discussed in section IV of 
this document, is available in the docket for this action.
---------------------------------------------------------------------------

     Rescind and remove the stayed and superseded findings of 
good neighbor obligations with respect to the 1997 8-hour ozone NAAQS 
at Sec.  51.121(a)(2), remove Sec.  51.121(q) staying the now-rescinded 
findings, and remove obsolete related language in Sec.  51.121(c)(1) 
and (2);
     Clarify the expression of Phase I and existing final 
emissions reduction requirements by removing the table of required 
incremental Phase II emissions reduction amounts at Sec.  51.121(e)(3), 
adding a column of Phase I budget amounts to the existing table of 
final budget amounts in Sec.  51.121(e)(2)(i), revising the definitions 
of ``Phase I SIP submission'' and ``Phase II SIP submission'' at Sec.  
51.121(a)(3)(i) and (ii), and making related revisions at Sec.  
51.121(b)(1) introductory text and (b)(1)(i);
     Remove Sec.  51.121(e)(4), which governs the former 
compliance supplement pool;
     Remove Sec.  51.121(e)(5), which sets forth a one-time 
process for revising the emissions inventories and budgets published as 
part of the original Rule;
     Remove Sec.  51.121(g)(2)(ii), which contains an obsolete 
table of baseline emissions inventory information originally intended 
to help states prepare their required SIP revisions;
     Remove Sec.  51.121(p) and (b)(2), which authorize the use 
of the former NBTP and other potential interstate trading programs, 
respectively, as compliance options;
     Make clarifying revisions to Sec.  51.121(r)(2), which 
sets forth the post-NBTP transition requirements;
     Remove Sec.  51.121(d)(1), which contains obsolete 
deadlines for Phase I and Phase II SIP submissions, and Sec.  
51.121(d)(2), which contains obsolete or duplicative procedural 
provisions concerning the completeness and format of SIP submissions;
     Remove or update obsolete cross-references in the 
NOX SIP Call regulations at Sec. Sec.  51.121(b)(1)(i), 
(g)(2)(i) and (r)(1) and (2) and 51.122(c)(1)(ii) and in the CSAPR 
regulations at

[[Page 8428]]

Sec.  52.38(b)(8)(ii), (b)(8)(iii)(A)(2), (b)(9)(ii), and 
(b)(9)(iii)(A)(2); and
     Make clarifying editorial revisions to Sec.  51.121 
heading, (b)(1)(ii), (e)(2)(ii)(B) and (E), (f)(2)(i)(B), (f)(2)(ii), 
(h), (i)(2),(3), and (5), (l)(1) and (2), (m), (n), and (o).
    These proposed further amendments as well as EPA's supporting 
rationales are fully discussed in the proposal.\28\ The discussions in 
the proposal are incorporated herein and are not summarized further in 
this document except as necessary to respond to comments in sections 
III.B. through III.D of this document.
---------------------------------------------------------------------------

    \28\ 83 FR at 48758-61.
---------------------------------------------------------------------------

D. Public Comment Process

    In the proposal, EPA requested comment on the proposed amendment to 
revise the provision at 40 CFR 51.121(i)(4) to allow states to 
establish monitoring requirements for large EGUs and large non-EGU 
boilers and turbines in their SIPs other than part 75 monitoring 
requirements. With respect to the remaining proposed amendments, EPA 
made clear that the amendments were not intended to substantively alter 
existing regulatory requirements and consequently requested comment 
solely on whether the provisions proposed for removal as obsolete in 
fact are obsolete and on whether the proposed clarifications in fact 
achieve clarification. EPA did not reopen for comment any provisions of 
the existing NOX SIP Call regulations except the provisions 
that were proposed to be amended as discussed in the proposal \29\ and 
did not reopen or request comment on amending any other existing 
regulations. The proposal also provided information on how to request a 
public hearing. No public hearing was held because none was requested, 
and the public comment period closed on October 29, 2018.
---------------------------------------------------------------------------

    \29\ Regulatory findings and requirements that EPA did not 
propose to substantively amend include (but are not limited to) the 
findings of good neighbor obligations with respect to the 1979 1-
hour ozone NAAQS, the requirements for SIPs to contain control 
measures addressing these obligations, the final NOX 
budgets, the requirement for enforceable limits on seasonal 
NOX mass emissions for large EGUs and large non-EGU 
boilers and turbines where states have included control measures for 
these types of sources in their SIPs, the requirement for states to 
adopt replacement control measures into their SIPs to achieve the 
emissions reductions formerly projected to be achieved by the NBTP, 
and the general requirements for enforceability and for monitoring 
of the status of compliance with the control measures adopted.
---------------------------------------------------------------------------

III. Response to Comments

    Commenters on the proposal included states, source owners, industry 
associations, environmental organizations, and persons commenting as 
individuals. The comments are available in the docket for this action. 
In this section, EPA summarizes and responds to the comments regarding 
the proposed amendments, including requests for clarification. Sections 
III.A through III.D. address the proposed amendments to the 
NOX SIP Call's provisions concerning emissions monitoring 
requirements, emissions reduction requirements, the baseline emissions 
inventory table, and post-NBTP transition requirements, respectively.
    With respect to the proposed amendments not addressed in sections 
III.A. through III.D., EPA received no adverse comments or requests for 
clarification. One commenter stated no objection to or supported most 
of these amendments individually, and additional commenters expressed 
general support for all the amendments removing obsolete provisions or 
all the amendments clarifying the remaining regulations. EPA thanks the 
commenters for these comments, which are not discussed further in this 
document.
    Some commenters also submitted comments on topics other than the 
NOX SIP Call regulations. These comments are outside the 
scope of the proposal and are not discussed further in this document.

A. Emissions Monitoring Requirements

    Comment: Most commenters supported the proposed amendment to the 
NOX SIP Call's monitoring requirements. These commenters 
generally expressed the view that requirements to perform part 75 
monitoring solely for purposes of the NOX SIP Call are no 
longer necessary to ensure states' compliance with the Rule's emissions 
reduction requirements. Most of these commenters also generally 
indicated that allowing the use of alternate monitoring requirements 
would result in reduced monitoring costs for some sources.
    Response: EPA agrees with these comments' support for the proposed 
amendment to the Rule's monitoring requirements.
    Comment: Some commenters, while generally supporting the proposed 
monitoring amendment, stated that EPA should also make further 
amendments to the NOX SIP Call's monitoring provisions to 
authorize particular forms of alternate monitoring requirements. 
Specifically, two commenters requested an amendment providing that, if 
a demonstration is made that emissions from a state's large non-EGU 
boilers and turbines ``will not exceed the [emissions] budget . . . 
established'' for such sources, then those sources would be allowed to 
determine reported NOX emissions according to a methodology 
based on the use of emission factors--that is, factors approved as 
estimates of the quantity of NOX emitted per unit of fuel 
combusted--and information on fuel consumption. Another commenter 
requested an amendment to authorize methodologies involving the use of 
gas concentration CEMS installed and operated in accordance with the 
provisions of 40 CFR part 60 in addition to the monitoring methodology 
preferred by the two previously mentioned commenters. Another 
commenter, without expressing a preference for a particular form of 
alternate monitoring requirements, recommended that EPA issue model 
rule language for alternate monitoring requirements that would be 
approvable in SIP revisions.
    Most commenters supporting the proposed monitoring amendment did 
not request that EPA make further amendments to identify particular 
permissible alternate monitoring requirements or issue model rule 
language. One of these commenters specifically recommended that EPA 
defer to states' choices regarding alternate monitoring requirements to 
the maximum extent allowable.
    Response: EPA disagrees with the comments seeking further 
amendments to identify specifically permissible alternate monitoring 
requirements or issue model rule language and agrees with the comments 
supporting the monitoring amendment as proposed without such further 
amendments. Upon finalization of the proposed amendment to the 
NOX SIP Call regulations making the inclusion of part 75 
monitoring requirements in SIPs optional rather than mandatory, states 
would have the flexibility to establish their own preferred forms of 
monitoring requirements for NOX SIP Call purposes, subject 
to the existing general provisions at Sec.  51.121(i) introductory text 
and (i)(1) concerning SIP monitoring requirements--provisions that EPA 
did not propose to amend. Under the general monitoring provisions, 
which closely parallel the longstanding provisions concerning SIP 
source surveillance requirements at 40 CFR 51.210 and 51.211, each SIP 
revision must provide for monitoring the status of compliance with any 
control measures adopted to achieve the NOX SIP Call's 
emissions reduction requirements, and the monitoring must be sufficient 
to determine whether sources are in compliance with the control 
measures. Nothing in these

[[Page 8429]]

general monitoring provisions precludes the commenters' preferred forms 
of monitoring requirements where such requirements are shown to be 
sufficient to meet these criteria. Thus, the further amendments 
suggested by the commenters are unnecessary, because where a state 
agrees that the commenters' preferred forms of monitoring requirements 
are appropriate, the state may obtain approval of those requirements 
simply by submitting a SIP revision that adopts those requirements and 
demonstrating that the revision satisfies the general monitoring 
provisions and does not conflict with any other applicable CAA 
requirement.\30\ For the same reasons that EPA considers it reasonable 
under current circumstances to make part 75 monitoring optional rather 
than mandatory for NOX SIP Call purposes (as discussed in 
section II.B. of this document), EPA also considers it reasonable to 
defer to states' choices regarding alternate monitoring requirements 
for NOX SIP Call purposes to the extent consistent with the 
general monitoring provisions at Sec.  51.121(i) introductory text and 
(i)(1).
---------------------------------------------------------------------------

    \30\ EPA notes that for purposes of demonstrating that the 
replacement monitoring requirements would be sufficient to ensure 
compliance with the emissions requirements, a state generally would 
be able to cite the same types of data that EPA presented in the 
proposal to support the proposed amendment to the NOX SIP 
Call's monitoring requirements.
---------------------------------------------------------------------------

    In addition, EPA believes that inclusion of the suggested further 
amendments would not be particularly useful in providing certainty of 
the approvability of any specific state regulation implementing the 
commenters' preferred forms of monitoring requirements. Notwithstanding 
any endorsement of a particular overall monitoring approach that EPA 
might include in the regulations, given the need to satisfy the 
NOX SIP Call's general monitoring provisions just discussed, 
EPA would still need to individually review the specific alternate 
monitoring requirements in each SIP revision to support a determination 
that the monitoring is sufficient to ensure compliance with the 
NOX SIP Call's emissions reduction requirements. For 
example, EPA would need to consider whether each regulation contains 
adequate provisions to avoid gaps in required monitoring and whether a 
regulation following an emission factor approach employs emission 
factors that are designed to avoid any bias toward understatement of 
emissions. Approval of each SIP revision would also be subject to 
notice-and-comment procedures. While in theory EPA could provide 
greater certainty of the approvability of certain forms of alternate 
monitoring requirements by issuing model rule language, EPA believes 
issuance of such language in this instance is neither necessary nor 
consistent with EPA's general intent of deferring to states' 
preferences regarding alternate monitoring requirements for 
NOX SIP Call purposes.
    Comment: One commenter stated that amending the NOX SIP 
Call regulations to allow sources that currently monitor using CEMS to 
switch to alternate monitoring methods would be inconsistent with CAA 
section 110(l), 42 U.S.C. 7410(l), known as the ``anti-backsliding'' 
provision, which prohibits EPA from approving any implementation plan 
revision that would interfere with any applicable requirement under the 
CAA. The commenter stated that effective and accurate emissions 
monitoring is needed to protect against backsliding and that allowing 
sources to use monitoring approaches less effective than CEMS 
monitoring would be inconsistent with section 110(l) because it would 
deprive communities and regulators of timely or reliable emissions 
information needed to identify possible violations of emissions 
standards and to facilitate enforcement actions.
    Response: EPA disagrees with this comment. As a preliminary matter, 
EPA notes that CAA section 110(l) applies to EPA actions determining to 
approve implementation plan revisions, not other EPA actions that might 
affect the matters that are required to be addressed through such 
implementation plan revisions. Thus, this action to amend the 
NOX SIP Call regulations is not subject to section 110(l). 
At the same time, no Agency-issued regulation can negate or otherwise 
modify the Congressionally-established prohibition in section 110(l) 
against approval of implementation plan revisions that would permit 
backsliding. For this reason, notwithstanding the content of any 
amendment to the NOX SIP Call regulations finalized in this 
action, approval of any SIP submissions made in response to such an 
amendment will necessarily still be subject to anti-backsliding 
requirements under section 110(l).
    Substantively, the proposed amendment to monitoring requirements is 
not inconsistent with the purpose of section 110(l) because there is no 
reason to expect that a SIP submission seeking only to revise 
monitoring requirements for NOX SIP Call purposes would 
result in increased emissions or otherwise interfere with any other CAA 
requirement, in light of the criteria for approval of such a SIP 
submission. That is, the amendments proposed for this action make no 
changes to the NOX SIP Call's existing regulatory 
requirements related to statewide emissions budgets or enforceable mass 
emissions limits for large EGUs and large non-EGU boilers and turbines. 
As discussed in response to a previous comment, under Sec.  51.121(i) 
introductory text and (i)(1) any alternate monitoring requirements 
approved into a SIP for NOX SIP Call purposes must be 
sufficient to determine whether the state's sources are in compliance 
with the control measures adopted to meet the Rule's emissions 
requirements. Given continued implementation of SIP requirements 
governing the unchanged amounts of allowable emissions, accompanied by 
replacement monitoring requirements sufficient to ensure compliance 
with the unchanged emissions requirements, a SIP revision adopted in 
response to the proposed amendments would not be expected to result in 
increases in emissions that could interfere with other statutory or 
regulatory requirements.
    The commenter's suggestion that CEMS emissions data provided 
pursuant to NOX SIP Call requirements is necessary to 
provide emissions information to identify violations of and enforce 
other emissions standards is outside the scope of the proposal. The 
NOX SIP Call's monitoring requirements were promulgated to 
provide monitoring information sufficient to ensure compliance with the 
control measures adopted to achieve the Rule's emissions reduction 
requirements.\31\ Monitoring requirements to ensure compliance with 
other emissions requirements are generally established as part of the 
regulations that establish each specific emissions requirement or 
through monitoring-focused regulations such as the source surveillance 
regulations at 40 CFR part 51, subpart K, or the compliance assurance 
monitoring regulations at 40 CFR part 64. Any concerns about the 
adequacy of the monitoring requirements established under other 
regulations would be properly raised as comments in the actions 
promulgating those regulations or as requests for new rulemaking, not 
as comments on this action addressing monitoring requirements under the 
NOX SIP Call regulations. In the proposal for this action, 
EPA did not propose to alter any monitoring requirements under any

[[Page 8430]]

regulations other than the NOX SIP Call regulations.
---------------------------------------------------------------------------

    \31\ See 83 FR at 48757.
---------------------------------------------------------------------------

    Comment: One commenter stated that amending the NOX SIP 
Call regulations to allow sources that currently monitor using CEMS to 
switch to alternate monitoring methods would be inconsistent with CAA 
section 504(b), 42 U.S.C. 7661c(b), which authorizes EPA to prescribe 
monitoring requirements for the operating permits that certain sources 
are required to obtain pursuant to CAA title V. The commenter cited a 
portion of the provision stating that ``continuous emissions monitoring 
need not be required if alternative methods are available that provide 
sufficiently reliable and timely information for determining 
compliance'' and stated that because CEMS monitoring is the most 
reliable and timely monitoring method for determining compliance with 
NOX emissions limits, it would be unreasonable and 
inconsistent with section 504(b) for EPA to allow sources which already 
have CEMS equipment installed to use less reliable and timely 
monitoring approaches.
    Response: EPA disagrees with this comment. While CAA section 504(b) 
provides EPA with authority to prescribe monitoring requirements for 
title V operating permits, it does not require EPA to exercise that 
authority in any particular situation and hence does not impose any 
statutory requirement applicable to this action. Further, even 
accepting for purposes of argument the comment's premise that the 
conditions that would apply to an exercise of EPA's authority under 
section 504(b) should also apply to EPA's establishment of monitoring 
requirements for NOX SIP Call purposes, the proposed 
monitoring amendment is neither unreasonable nor inconsistent with 
those conditions. As noted in the comment, section 504(b) explicitly 
provides that EPA need not exercise its authority under the section so 
as to require CEMS in circumstances where alternate monitoring methods 
sufficient to determine compliance are available. In the proposal, EPA 
presented recent emissions data and expressed the view that, given the 
current substantial margins by which the sets of large EGUs and large 
non-EGU boilers and turbines in all NOX SIP Call states are 
complying with the relevant portions of the statewide emissions budgets 
as well as the fact that most of the relevant emissions will continue 
to be monitored according to part 75 under other programs, monitoring 
of the remaining emissions using non-part 75 approaches can now provide 
sufficient assurance that the Rule's required emissions reductions will 
continue to be achieved.\32\ The commenter does not challenge EPA's 
assessment. EPA's rationale for proposing the amendment closely 
parallels and is fully consistent with the conditions set forth in 
section 504(b) for the possible establishment of monitoring 
requirements other than CEMS monitoring requirements.
---------------------------------------------------------------------------

    \32\ 83 FR at 48757-58.
---------------------------------------------------------------------------

    Moreover, neither of the commenter's stated reasons for suggesting 
that it would be unreasonable or inconsistent with section 504(b) for 
EPA to allow the use of non-CEMS approaches is compelling. The first 
stated reason--that CEMS-based monitoring approaches would provide the 
most reliable and timely information for determining compliance with 
NOX emission limits--is itself inconsistent with the 
statutory text which, as just discussed, explicitly indicates the 
potential acceptability of non-CEMS monitoring approaches that provide 
sufficient reliability and timeliness of information for determining 
compliance. The second stated reason--that the sources in question 
already have CEMS equipment installed--is incorrect for some of the 
sources potentially affected by the monitoring amendment and materially 
incomplete for all of them. The set of large EGUs and large non-EGU 
boilers and turbines subject to the NOX SIP Call's ongoing 
requirements discussed in this document includes both existing and new 
units. Some new units that would need to install CEMS equipment if 
required to monitor under part 75 might not need to install some or all 
of that CEMS equipment if part 75 monitoring were not required for 
NOX SIP Call purposes. Further, as discussed in the 
proposal, even for a source that already has CEMS equipment installed, 
the source's ongoing operating costs to monitor using the installed 
CEMS equipment could be higher than the source's ongoing operating 
costs if the source were to switch to a non-CEMS monitoring 
approach.\33\ Besides the factor of whether non-CEMS monitoring 
approaches that provide sufficiently reliable and timely information 
for determining compliance are available, the text of section 504(b) 
does not specify or limit other factors that EPA may consider when 
applying its authority under the section. Thus, it is neither 
unreasonable nor inconsistent with section 504(b) for EPA to consider 
the likelihood that some sources would incur lower monitoring costs if 
allowed to use non-CEMS monitoring approaches for NOX SIP 
Call purposes.
---------------------------------------------------------------------------

    \33\ 83 FR at 48761. Several commenters also discussed the 
significance of the operating and maintenance costs that are 
incurred to comply with monitoring requirements. See comments of 
North Carolina, Alcoa, Citizens Energy, Council of Industrial Boiler 
Owners, and Virginia Manufacturers Association.
---------------------------------------------------------------------------

    Comment: One commenter summarized several provisions of CAA section 
110(a), 42 U.S.C. 7410(a), concluding with the interpretation that ``a 
bedrock requirement for any implementation plan is for emissions 
monitoring requisite to ensure attainment and maintenance of the 
NAAQS.'' The commenter further stated that the current network of 
ambient air quality monitors is ``not robust enough to adequately 
assess levels of [ozone and particulate matter] in ambient air'' and 
cited a study concerning satellite-based measurements of ambient air 
quality. The commenter concluded that ``[g]iven this level of under-
assessment of pollution problems and dramatic[ ] undercounting of 
nonattainment issues,'' the proposed amendment to allow states to 
establish alternate emissions monitoring requirements ``is wholly 
inconsistent with the Clean Air Act's requirements.''
    Response: EPA disagrees that the proposed amendment to the 
NOX SIP Call regulations would be inconsistent with the 
statutory requirements under CAA section 110(a). The comment conflates 
the statutory provision authorizing EPA to prescribe emissions 
monitoring requirements for individual sources under CAA section 
110(a)(2)(F) with the general requirement for ambient air quality 
monitoring under CAA section 110(a)(2)(B). Contrary to the commenter's 
interpretation of CAA section 110(a), the data used to determine 
whether air quality in a given area meets the ozone or PM2.5 
NAAQS are the data obtained through the ambient air quality monitoring 
network, not the data obtained through source emissions monitoring. 
Similarly, assessments of whether the emission control measures in 
effect are collectively sufficient to ensure attainment and maintenance 
of those NAAQS are made using monitored ambient air quality data or 
projected ambient air quality data (which necessarily reflect 
projected, not monitored, source emissions data). The amendments 
proposed for this action would not alter any regulatory requirements 
concerning ambient air quality monitoring, and comments on this topic 
are outside the scope of the proposal.
    As discussed in response to a previous comment, the originally 
intended purpose served by the emissions monitoring requirements under 
the NOX SIP Call was to ensure compliance with the control 
measures

[[Page 8431]]

adopted to achieve the Rule's emissions reduction requirements, not to 
ensure attainment and maintenance of the NAAQS. Amendment of the 
NOX SIP Call as proposed for this action would not alter the 
provisions at Sec.  51.121(i) introductory text and (i)(1) that set 
forth the ongoing general requirement for SIPs to include emissions 
monitoring sufficient for this purpose. The amendment would simply 
expand the options available to states for addressing the ongoing 
general requirement by eliminating the additional specific requirement 
at Sec.  51.121(i)(4) for part 75 monitoring by large EGUs and large 
non-EGU boilers and turbines. Like the NOX SIP Call's 
initial monitoring requirements, the Rule's monitoring requirements as 
amended would be fully consistent with CAA section 110(a)(2)(F), which 
authorizes EPA to prescribe emissions monitoring and reporting SIP 
requirements that may include requirements for ``correlation of such 
[emissions] reports by the State agency with any emission limitations 
or standards'' established under the CAA.
    Comment: One commenter discussed the data EPA presented in the 
proposal regarding recent emissions reported by the sources that would 
have been subject to the former NBTP. While not disputing EPA's 
assessment that the data show that the sources in all states subject to 
the NOX SIP Call are currently complying with the assigned 
portions of their respective statewide budgets by substantial margins, 
the commenter asserted that EPA's reliance on the data to support the 
proposed amendment to the Rule's monitoring requirements is misguided. 
The commenter questioned the relevance of EPA's assessment that non-
part 75 monitoring by the sources not subject to part 75 monitoring 
requirements under other programs could now provide assurance of 
continued compliance with the NOX SIP Call's emissions 
reduction requirements, suggesting that EPA should instead consider 
emissions targets more stringent than the Rule's existing budgets.
    With regard to EPA's assessment that the substantial majority of 
emissions from large EGUs and large non-EGU boilers and turbines would 
continue to be monitored according to part 75 under other programs, the 
commenter observed that in certain states, the emissions from the 
subset of large EGUs and large non-EGU boilers and turbines potentially 
affected by the proposed monitoring amendment can be significant 
relative to the emissions from the remaining large EGUs and large non-
EGU boilers and turbines that must continue to monitor their emissions 
under part 75 for other programs. Based on this observation, the 
commenter concluded that, in these states, allowing the potentially 
affected sources to monitor using non-CEMS methodologies ``will notably 
degrade the overall NOX emissions data'' from the sets of 
large EGUs and large non-EGU boilers and turbines in the states. The 
commenter also stated that the total amount of seasonal NOX 
emissions from the potentially affected sources--approximately 15,000 
tons in the 2017 ozone season--is ``not trivial,'' but is significant 
in an absolute sense regardless of its relation to the amount of 
emissions from the sources that would still be subject to part 75 
monitoring requirements under other programs. Noting that annual 
emissions of 100 tons can trigger classification of certain types of 
new or modified sources as ``major sources'' under other CAA programs, 
the commenter suggested that allowing sources that collectively produce 
15,000 tons of seasonal NOX emissions to stop using CEMS is 
comparable to excusing as many as 360 major sources from requirements 
to use NOX CEMS under other programs.
    Response: EPA continues to believe that the emissions data 
presented in the proposal provide compelling support for the proposed 
amendment to the NOX SIP Call's emissions monitoring 
requirements. EPA disagrees with the commenter's suggestion that in 
evaluating possible changes to monitoring requirements under the 
NOX SIP Call, rather than assessing whether alternate forms 
of monitoring would be sufficient to ensure compliance with the Rule's 
existing emissions reduction requirements, EPA should instead consider 
whether the alternate monitoring requirements would be sufficient to 
ensure compliance with more stringent emissions targets. As discussed 
in response to a previous comment, the Rule's monitoring requirements 
were established to provide monitoring information sufficient to ensure 
compliance with the control measures adopted to achieve the Rule's 
required emissions reductions, and monitoring requirements to ensure 
compliance with other emissions requirements are established in other 
regulations. Comments concerning whether the Rule's existing emissions 
reductions requirements are sufficiently stringent are outside the 
scope of the proposal. EPA did not propose to substantively alter any 
regulatory requirements other than the NOX SIP Call's 
monitoring requirements.
    With regard to the commenter's observations concerning the relative 
magnitudes of the respective total amounts of emissions from sources 
potentially affected by the proposed monitoring amendment and other 
sources in certain states, EPA acknowledges that emissions from the 
potentially affected sources comprise larger shares of the total 
emissions from large EGUs and large non-EGU boilers and turbines in 
some states than others but disagrees with the suggestion that this 
fact should foreclose the possibility of allowing monitoring 
flexibility for NOX SIP Call purposes. According to the 
recent emissions data presented in the proposal \34\ and reproduced in 
Table 1 in section II.B. of this document, for six of the states 
identified in the comment--Alabama, Maryland, New Jersey, New York, 
South Carolina, and Tennessee--the total amount of emissions from the 
state's potentially affected sources was from 19% to 30% of the total 
amount of emissions from the state's remaining large EGUs and large 
non-EGU boilers and turbines, and for the last identified state--
Delaware--the emissions from the state's potentially affected sources 
exceeded the emissions from the state's remaining large EGUs and large 
non-EGU boilers and turbines. However, even accepting the commenter's 
premise that allowing the potentially affected sources in these states 
to switch from CEMS methodologies to non-CEMS methodologies would 
reduce the accuracy of the total reported amounts of emissions from 
large EGUs and large non-EGU boilers and turbines, EPA believes that 
the compliance margins in these states are large enough that there 
would still be sufficient assurance that the NOX SIP Call's 
emissions reduction requirements would continue to be achieved. In each 
of these states (as well as all the other states subject to the 
NOX SIP Call), the emissions data in Table 1 indicate that, 
assuming no increase in the total emissions from the sources in the 
state that would continue to be subject to part 75 monitoring under 
other programs, the total emissions from the state's potentially 
affected sources could increase at least eightfold without causing the 
total emissions from the state's large EGUs and large non-EGU boilers 
and turbines to exceed the relevant portion of the statewide emissions 
budget.\35\ Thus, again

[[Page 8432]]

assuming no increase in the total emissions from the sources in the 
state that would continue to be subject to part 75 monitoring under 
other programs, even if the total reported emissions data for the set 
of potentially affected sources in a state in some future ozone season 
were to understate the true emissions data because of less accurate 
measurements made using non-CEMS methodologies, in order for the total 
reported emissions data to incorrectly indicate compliance for the 
state when the true emissions data would indicate non-compliance, the 
cumulative measurement errors causing understatement of the true data--
that is, the differences between the reported emissions data values and 
the true emissions data values for each source--would have to be 
several times larger than the reported data values.\36\ The commenter 
does not suggest, and EPA does not believe, that the accuracy of non-
CEMS monitoring approaches would be so poor as to allow such a scenario 
to occur. Moreover, if the commenter believes that the specific 
alternate monitoring approaches included in a particular state's SIP 
revision submitted for EPA's approval would provide insufficiently 
accurate data to ensure continued compliance with the control measures 
adopted in the state's SIP for NOX SIP Call purposes, the 
notice-and-comment process for approval of the SIP revision would 
provide an opportunity for the commenter to raise that concern.
---------------------------------------------------------------------------

    \34\ See 83 FR at 48758 (Table 1).
    \35\ The recent compliance margins for the individual 
NOX SIP Call states indicated by the data in Table 1 
range from 8.6 times to over 300 times the total reported emissions 
from the respective states' sets of potentially affected sources. 
For example, for Alabama, the data in Table 1 indicate a compliance 
margin of 16,420 tons (25,497-9,077 = 16,420), which is 8.6 times 
the reported emissions from the state's potentially affected sources 
(16,420 / 1,911 = 8.6).
    \36\ For illustrative purposes, this example assumes both that 
the collective emissions from potentially affected sources in a 
state would increase by the amount necessary to cause non-compliance 
for the state and that the alternate monitoring methodologies would 
fail to register the increase in emissions. EPA does not believe 
these assumptions have a reasonable basis and is using them only to 
respond to the commenter's concerns regarding accuracy.
---------------------------------------------------------------------------

    With regard to the commenter's observations concerning the 
significance of the total seasonal NOX emissions from the 
potentially affected sources in an absolute sense, EPA agrees that a 
15,000-ton quantity of seasonal NOX emissions is ``not [a] 
trivial'' amount but disagrees with the suggestion that this fact 
should foreclose the possibility of allowing monitoring flexibility for 
NOX SIP Call purposes. The proposed amendments would not 
alter any of the Rule's regulatory requirements concerning permissible 
amounts of emissions and would not eliminate the requirement for SIPs 
to provide for monitoring of the emissions from all large EGUs and 
large non-EGU boilers and turbines sufficient to ensure continued 
compliance with the Rule's emissions reduction requirements. Nor does 
EPA agree that allowing non-CEMS monitoring approaches to be used for 
purposes of demonstrating compliance with control measures adopted 
under the NOX SIP Call is comparable to excusing major 
sources from requirements to monitor using CEMS for other purposes. The 
amendments proposed for this action are based on EPA's assessment, 
specific to this action, that under current circumstances monitoring 
information from some sources other than part 75 monitoring information 
can now provide sufficient assurance that the NOX SIP Call's 
required emissions reductions will continue to be achieved. Where any 
source is required to monitor using CEMS for another purpose under 
regulations other than the NOX SIP Call regulations, the 
amendments proposed for this action would not affect those 
requirements.
    Comment: One commenter contended that allowing alternate monitoring 
requirements will lead to increased emissions. The commenter observed 
that EPA did not know which specific sources might ultimately be 
allowed to use alternate monitoring methods. According to the 
commenter, EPA had suggested in the proposal that the potential for 
increases in pollution resulting from alternate monitoring requirements 
is merely uncertain, because EPA would not itself relax the 
requirements but would leave that decision to the states, and the 
commenter stated it is arbitrary and capricious for EPA to rely on such 
a claim of uncertainty to avoid assessing the impacts of increased 
pollution. The commenter contended that EPA had suggested in the 
proposal that ``systemwide NOX emissions are low enough that 
if there are increases in pollution attainment and maintenance [of the 
NAAQS] might not be threatened.'' The commenter also discussed ozone 
pollution and the harms it causes to human health and the environment, 
citing several EPA documents.
    Response: EPA does not dispute the commenter's summary of the harms 
caused by ozone pollution or the correct observation that EPA does not 
know which specific sources might ultimately be allowed to use 
alternate monitoring methods (because states, not EPA, will decide 
whether to revise their SIPs). Otherwise, EPA disagrees with these 
comments. Relative to part 75 monitoring approaches, non-part 75 
monitoring approaches may be expected to provide less detailed 
monitoring data and require less rigorous quality assurance, with a 
consequently greater possibility that the total NOX 
emissions amount reported by a source for a given ozone season might 
understate or overstate the source's actual total emissions for that 
ozone season to some degree. However, there is no reason to expect any 
approved non-part 75 monitoring methodology either to be systematically 
biased toward understatement of emissions or to create any incentive 
leading to increased emissions. EPA was clear in the proposal that no 
changes to emissions or air quality are expected because no changes are 
being made to the NOX SIP Call's emissions requirements.\37\ 
The commenter effectively equates allowing alternate monitoring methods 
with relaxing emissions requirements, providing no rationale or 
evidence to support the contention that in the absence of any change in 
either emissions requirements or the general requirement to monitor 
emissions, possible changes in just the allowed methods for emissions 
monitoring under the NOX SIP Call will lead to increased 
emissions. EPA continues to believe it is reasonable to assume that 
under current circumstances where sources are already complying with 
the NOX SIP Call's emissions requirements by substantial 
margins, substitution of one monitoring method for another monitoring 
method, in the absence of any change in the Rule's emissions 
requirements, will not cause sources to change their behavior in a way 
that would affect emissions levels. Moreover, in the event that a 
particular state's SIP submission were to include a poorly designed 
alternate monitoring requirement that could lead to systematic 
understatement of emissions, the SIP approval process--including 
notice-and-comment procedures--would provide a further safeguard 
against the possibility of alternate monitoring requirements 
insufficient to ensure compliance with the Rule's emissions 
requirements. The commenter appears to incorrectly assume that the 
amendment in this action would by itself end all EPA oversight of 
monitoring requirements for NOX SIP Call purposes and fails 
to acknowledge the additional safeguard afforded by the SIP approval 
process.
---------------------------------------------------------------------------

    \37\ 83 FR at 48761.
---------------------------------------------------------------------------

    The commenter's claims regarding suggestions that EPA purportedly 
made about the supposed possibility of increased emissions misrepresent 
the proposal. Contrary to the comments, nowhere in the proposal did EPA 
indicate ``uncertainty'' as to whether the proposed amendments would 
lead to

[[Page 8433]]

increased pollution. Rather, as just discussed, EPA explicitly stated 
that the proposed amendments are expected to have no impact on 
emissions or air quality. The fact that states, rather than EPA, will 
decide whether to revise their SIPs to establish alternate monitoring 
requirements was cited in the proposal as a basis for uncertainty with 
regard to the potential amount of reductions in monitoring costs, not 
as a basis for uncertainty with regard to supposed potential increases 
in emissions.\38\ Likewise, nowhere in the proposal did EPA make any 
suggestion regarding the relationship of supposed potential increases 
in emissions to the likelihood of attainment or maintenance of any 
NAAQS. Rather, as an illustration of the magnitude of states' recent 
margins of compliance with the NOX SIP Call's emissions 
reduction requirements, EPA stated only that such compliance would 
continue to be achieved even if emissions were to increase 
substantially from current levels, and then proceeded to explain why 
such increases in emissions in fact are unlikely to occur.\39\
---------------------------------------------------------------------------

    \38\ 83 FR at 48761.
    \39\ 83 FR at 48757 & nn.38-39.
---------------------------------------------------------------------------

    Comment: One commenter suggested that the proposal did not address 
relevant differences among the states and source types that could be 
affected by the proposed monitoring amendment. The commenter stated 
that the proposal failed to identify which sources affected under the 
NOX SIP Call do not participate in any CSAPR trading 
program. Noting that several NOX SIP Call states are outside 
the region covered by the various CSAPR trading programs, the commenter 
asserted that EPA had failed to explain ``why sources in some areas 
should be allowed to monitor less and pollute more,'' and that ``EPA is 
thus effectively proposing to end continuous NOX monitoring 
for an entire geographic area without discussing the ensuing 
implications.'' Noting that the NOX SIP Call applies to both 
EGUs and non-EGUs while the CSAPR trading programs generally apply only 
to EGUs, the commenter further asserted that EPA did not ``coherently 
address the distinction between the types of sources'' (emphasis in 
original) covered by the NOX SIP Call and the CSAPR trading 
programs. Repeating the contention that allowing alternate monitoring 
methods will lead to increased emissions, the commenter suggested that 
EPA should have evaluated the impacts on regional ozone transport 
problems of allowing alternate monitoring methods for some states and 
source types but not others.
    Response: EPA disagrees with these comments. Contrary to the 
commenter's suggestion, the proposal explicitly discussed differences 
among NOX SIP Call states concerning whether each state's 
EGUs are covered by a CSAPR trading program, noting that EGUs in 
Connecticut, Delaware, Massachusetts, Rhode Island, and the District of 
Columbia do not participate in any CSAPR trading programs.\40\ 
Likewise, the commenter's assertion that the proposed monitoring 
amendment would ``end continuous NOX monitoring for an 
entire geographic region'' is directly contradicted by information in 
the proposal: First, by the explanation that most of the EGUs in the 
five non-CSAPR states will remain subject to part 75 monitoring 
requirements under the Acid Rain Program; \41\ second, by the 
explanation that most of the emissions from the set of large EGUs and 
large non-EGU boilers and turbines affected under the NOX 
SIP Call come from large EGUs that would continue to monitor their 
emissions according to part 75 under either the Acid Rain Program or a 
CSAPR trading program; \42\ and third, by the data showing 
quantitatively that out of the total set of sources subject to the 
NOX SIP Call in the five non-CSAPR states, the subset of 
sources that would continue to be subject to part 75 monitoring 
requirements under other programs has produced most of the recent 
emissions.\43\
---------------------------------------------------------------------------

    \40\ 83 FR at 48756 & nn.26-27. EPA notes that there are 
currently no large EGUs in the District of Columbia.
    \41\ 83 FR at 48756 & n.27.
    \42\ 83 FR at 48758 & n.40.
    \43\ See 83 FR at 48758 (Table 1) (also reproduced as Table 1 in 
section II.B. of this document). The sum of the emissions shown in 
Table 1 for the sources that would continue to be subject to part 75 
monitoring in the five non-CSAPR states is 1,631 tons. The sum of 
the emissions shown for the sources potentially affected by the 
proposed amendment in these states is 654 tons.
---------------------------------------------------------------------------

    Contrary to the commenter's assertion that the proposal failed to 
address the distinction between EGUs and non-EGUs, the proposal 
explicitly discussed the fact that unlike most EGUs, most non-EGUs 
affected under the NOX SIP Call do not participate in a 
CSAPR trading program or face part 75 monitoring requirements under 
other programs.\44\ The proposal also explicitly noted that although 
some of the sources potentially affected by the proposed monitoring 
amendment are large EGUs not subject to the Acid Rain Program or a 
CSAPR trading program, most of the potentially affected sources are 
large non-EGU boilers and turbines.\45\ The proposal presented recent 
state-specific emissions data broken out according to whether the 
emissions came from sources that would continue to be subject to part 
75 requirements under other programs or instead came from sources 
potentially affected by the proposed amendment.\46\ The proposal did 
not further break out the total recent emissions from potentially 
affected sources into the respective portions from EGUs and non-EGUs 
because EPA did not see any relevance in whether the NOX 
emissions that might be monitored for NOX SIP Call purposes 
using methods other than part 75 come from EGUs or from non-EGUs. The 
commenter has not suggested any reasons why further subcategorization 
of the emissions information provided in the proposal might be relevant 
to an evaluation of the proposed monitoring amendment. Nevertheless, to 
address the comment, EPA notes that large non-EGU boilers and turbines 
were collectively responsible for 14,860 tons of the total 15,084 tons 
of seasonal NOX emissions shown in Table 1 for all units 
potentially affected by the proposed monitoring amendment, or 98.5% of 
the total, while large EGUs not required to monitor according to part 
75 under the Acid Rain Program or a CSAPR trading program were 
collectively responsible for 224 tons, or 1.5% of the total.\47\
---------------------------------------------------------------------------

    \44\ 83 FR at 48751-52, 48755-56 & n.23.
    \45\ 83 FR at 48752.
    \46\ 83 FR at 48758 (Table 1).
    \47\ The potentially affected large EGUs are combustion turbines 
located in non-CSAPR states that serve generators larger than 25 MW 
and are exempt from the Acid Rain Program because they commenced 
commercial operation before November 15, 1990, and meet the 
definition of a ``simple combustion turbine'' in 40 CFR 72.2. There 
are currently 31 such units, all located in Connecticut, Delaware, 
or Massachusetts. The individual units are identified in the 
spreadsheet referenced in note 54 infra, available in the docket for 
this action.
---------------------------------------------------------------------------

    The comments suggesting that EPA should have evaluated the impacts 
on regional ozone transport problems of allowing alternate monitoring 
methods for some states and source types but not others reflect the 
commenter's unsupported assumption that allowing alternate monitoring 
methods is equivalent to relaxing emissions requirements. EPA has 
already rebutted the commenter's assumption in response to a previous 
comment. Because there is no reason to expect any increase in emissions 
from the proposed monitoring amendment, there is no reason to evaluate 
any impacts on regional ozone transport problems of any supposed 
potential increase in emissions.
    Comment: One commenter stated that EPA has not ``identif[ied] any 
need to weaken emission monitoring requirements'' (emphasis in 
original), has not identified specific complaints

[[Page 8434]]

from sources regarding the costs of operating monitoring equipment that 
has already been installed, and has not sufficiently discussed possible 
monitoring methodologies or compared their costs. The commenter also 
stated that allowing alternate monitoring requirements would unfairly 
advantage new sources over existing sources because the new sources, 
unlike existing sources, would be allowed ``to both use cheaper, less 
effective monitoring systems and to get away with emitting more 
NOX'' than existing sources.
    Response: EPA disagrees with these comments. In the proposal, EPA 
discussed the opportunity to reduce monitoring costs under the 
NOX SIP Call for some sources while continuing to ensure 
compliance with the Rule's emissions reduction requirements.\48\ By 
definition, a regulatory initiative that reduces overall costs while 
holding overall benefits constant produces positive net benefits. The 
commenter has not offered any legal basis or policy rationale 
supporting the notion that EPA should decline to pursue a regulatory 
initiative intended to produce positive net benefits simply because the 
net benefits happen to take the form of a reduction in sources' 
monitoring costs.
---------------------------------------------------------------------------

    \48\ 83 FR at 48761-62.
---------------------------------------------------------------------------

    The commenter's suggestion that EPA has presented insufficient 
evidence to support the existence of monitoring cost reduction 
opportunities is belied by the information in the proposal, which 
described the various monitoring methodologies available under part 75 
and qualitatively discussed the cost reductions that could be available 
if the sources using each of those methodologies were to switch to 
alternate monitoring methodologies.\49\ Moreover, all of the comments 
received on the proposal from source owners and industry associations, 
as well as most of the comments received from states, agreed that the 
proposed amendment would make monitoring cost reductions possible for 
sources in states that choose to revise their SIPs.\50\ The commenter 
asserted that sources had no reason to complain of monitoring costs 
because they had already installed the necessary CEMS equipment, but as 
EPA explained in response to a previous comment, this assessment is 
incorrect as to new sources, because new sources would not yet have 
installed the CEMS equipment, and materially incomplete as to all 
sources, because CEMS-related costs include not only equipment 
installation costs but also ongoing operating costs. EPA sees no reason 
why, in the absence of any contrary information, more evidence is 
needed to demonstrate the existence of opportunities for monitoring 
cost reductions than was already presented in the proposal, as further 
supported by comments.
---------------------------------------------------------------------------

    \49\ 83 FR at 48761 & nn.53-54.
    \50\ See comments from Indiana, Michigan, North Carolina, Ohio, 
South Carolina, Alcoa, Citizens Energy, Council of Industrial Boiler 
Owners, Illinois Environmental Regulatory Group, Ohio Manufacturers 
Association, Virginia Manufacturers Association, and West Virginia 
Manufacturers Association, available in the docket for this action.
---------------------------------------------------------------------------

    With respect to quantification of the potential reductions in 
monitoring costs, EPA explained in the proposal that because states, 
not EPA, would decide whether to revise the monitoring requirements in 
their SIPs and because EPA lacked complete information on the remaining 
monitoring requirements that the sources would face, it was not 
possible to predict the amount of monitoring cost reductions that could 
occur following finalization of the proposed monitoring amendment.\51\ 
EPA still lacks information on the remaining monitoring requirements 
that sources will face but received comments indicating some likelihood 
that at least six states would revise their SIPs following finalization 
of the proposed monitoring amendment. The states' comments make it 
possible to estimate a potential range of monitoring cost reductions 
that could occur if these states were to adopt some of the changes in 
monitoring requirements that EPA considers most likely. EPA's estimates 
are provided in section V of this document.
---------------------------------------------------------------------------

    \51\ 83 FR at 48761.
---------------------------------------------------------------------------

    Finally, the commenter's suggestion that the proposed monitoring 
amendment would unfairly advantage new sources over existing sources 
lacks any support. The NOX SIP Call's current requirements 
for part 75 monitoring apply to both existing and new sources, and upon 
finalization of the proposed monitoring amendment, states' flexibility 
to establish alternate monitoring requirements will likewise apply to 
both existing and new sources. Commenters have not suggested any reason 
to believe that states will choose to exercise this new flexibility in 
a manner that discriminates among their existing and new sources in 
terms of the prospective monitoring requirements established in their 
SIPs, and if the commenter is suggesting that EPA should require new 
sources to incur certain capital expenditures in the future simply 
because existing sources incurred those same capital expenditures in 
the past, EPA disagrees. Further, the commenter's assertion that the 
monitoring amendment will allow new sources to ``get away with emitting 
more NOX'' again rests on the commenter's unsupported 
assumption that allowing alternate monitoring methods is equivalent to 
relaxing emissions requirements. EPA has already rebutted the 
commenter's assumption in response to a previous comment. EPA also 
reiterates that the proposed monitoring amendment would not change any 
other emissions or monitoring requirements applicable to either 
existing or new sources under regulations other than the NOX 
SIP Call, including requirements that may be more stringent for new 
sources than existing sources.
    Comment: One commenter discussed the superiority of CEMS 
methodologies compared to non-CEMS monitoring methodologies in terms of 
the timeliness and reliability or accuracy of the emissions data 
collected, particularly with respect to NOX emissions, and 
cited various EPA documents in support. The commenter stated that EPA 
``should be enhancing the use of CEMS in emissions measurements'' 
instead of allowing monitoring flexibility. In particular, the 
commenter stated that the continued use of CEMS is necessary to ensure 
compliance with the Chesapeake Bay Total Maximum Daily Load (TMDL) for 
nitrogen established under the Clean Water Act. In support of this 
comment, the commenter summarized the role of atmospheric deposition as 
a contributor of nitrogen to Chesapeake Bay, citing studies by EPA and 
others. The commenter also noted that the plan for achieving the TMDL 
includes commitments from EPA to reduce atmospheric deposition through 
implementation of rules addressing CAA requirements, including the 
NOX SIP Call, and stated that EPA must maintain or 
strengthen air regulations in order to meet its commitments. The 
commenter stated that without accurate monitoring, states and EPA 
``will not know whether the reductions necessary to attain the Bay TMDL 
goals by 2025 are actually being met.''
    Response: EPA agrees that CEMS methodologies are often the 
preferred monitoring approaches for ensuring compliance with particular 
emissions requirements but disagrees that the acknowledged superiority 
of CEMS methodologies for some purposes should foreclose the 
possibility of allowing monitoring flexibility for NOX SIP 
Call purposes where other monitoring methods would be sufficient to 
ensure continued achievement of the Rule's emissions reduction 
requirements. Likewise, EPA does not dispute the commenter's summary 
regarding the Chesapeake Bay TMDL

[[Page 8435]]

and EPA's reliance on the NOX SIP Call's emissions 
reductions to reduce atmospheric deposition contributing nitrogen to 
the Bay but disagrees that those facts suggest that compliance with the 
Rule's emissions reduction requirements must be determined using any 
particular monitoring approach. As discussed in response to a previous 
comment, the NOX SIP Call's existing monitoring requirements 
were established to provide monitoring information sufficient to ensure 
compliance with the control measures adopted to achieve the Rule's 
required emissions reductions, and monitoring requirements to ensure 
compliance with other emissions requirements are established in other 
regulations. Comments concerning whether the NOX SIP Call's 
existing emissions reductions requirements are sufficiently stringent 
to address other environmental objectives, including achievement of the 
Chesapeake Bay TMDL, are outside the scope of the proposal. EPA did not 
propose to substantively alter any regulatory requirements other than 
the NOX SIP Call's monitoring requirements.
    Comment: One commenter supported a narrower amendment to the 
NOX SIP Call's monitoring requirements than EPA proposed. 
Specifically, the commenter supported an amendment that would allow 
states to eliminate the requirements for reporting emissions data to 
EPA under part 75 but would not allow the use of substantively 
different monitoring methodologies for collecting emissions data. The 
commenter objected to allowing sources that currently monitor emissions 
using CEMS to use other monitoring methodologies because, unlike CEMS 
methodologies, non-CEMS methodologies do not allow for accurate and 
timely determinations of compliance with or violations of short-term 
emission limits. The commenter also expressed the expectation that if 
the proposed amendment to emissions monitoring requirements is 
finalized, some states would be required to revise their SIPs to 
establish less stringent monitoring requirements because of provisions 
in state law barring the states from imposing requirements on sources 
that exceed minimum Federal requirements.
    Response: The comment expressing concern that non-CEMS 
methodologies are less useful than CEMS methodologies for determining 
compliance with emissions requirements other than the NOX 
SIP Call's emissions requirements is outside the scope of the proposal. 
As discussed in response to a previous comment, the NOX SIP 
Call's existing monitoring requirements were established to provide 
monitoring information sufficient to ensure compliance with the control 
measures adopted to achieve the Rule's required emissions reductions, 
and monitoring requirements to ensure compliance with other emissions 
requirements are established in other regulations. The NOX 
SIP Call does not require states to impose short-term emissions limits 
on their sources, and EPA did not propose to substantively alter any 
regulatory requirements other than the NOX SIP Call's 
monitoring requirements.
    The comment suggesting that some NOX SIP Call states 
would be required under state law to revise their SIPs if the proposed 
monitoring amendment is finalized has no bearing on this action. EPA's 
proper focus in this action is whether the proposed amendment to allow 
alternate monitoring requirements in SIPs is appropriate under the CAA. 
Questions of whether and how state law provisions might affect the 
decisions of individual states to adopt alternate monitoring 
requirements allowed under the amendment are outside EPA's purview.
    Comment: One commenter stated that allowing sources that currently 
monitor emissions for NOX SIP Call purposes with CEMS 
methodologies to instead monitor their emissions with non-CEMS 
methodologies would result in a loss of data resolution that would make 
it more difficult to understand the impacts of the sources' emissions 
on air quality in other states. The commenter stated that, with less 
detailed emissions data, it would be more difficult for states to work 
together to develop regionally consistent approaches for addressing 
good neighbor obligations with respect to the 2015 ozone NAAQS. The 
commenter also requested that EPA identify the specific units whose 
monitoring requirements could potentially be altered by states if the 
proposed monitoring amendment is finalized, as well as the locations of 
the units.
    Response: EPA disagrees that allowing the use of alternate 
monitoring requirements for NOX SIP Call purposes would 
materially impact the ability of states to work together to address 
their good neighbor obligations with respect to the 2015 ozone NAAQS in 
a regionally consistent manner. As discussed in section II.B. of this 
document, if the proposed amendment is finalized, over 90% of the 
emissions from the set of NOX SIP Call large EGUs and large 
non-EGU boilers and turbines would still be monitored according to part 
75 under other regulations if the relative proportions shown for 2017 
in Table 1 continue into the future. In addition, the potentially 
affected sources in states that choose to revise their SIPs would still 
need to provide emissions monitoring information for each ozone season 
sufficient for the state to demonstrate compliance with the Rule's 
emissions reduction requirements. The commenter has not explained the 
purpose for which the enhanced data resolution provided by part 75 
monitoring is desired. In any event, EPA notes that projected hourly 
emissions data for use in air quality modeling could be prepared based 
on the intra-year time patterns in the extensive historical emissions 
data reported by the sources for periods while the sources have been 
subject to part 75, because those data would remain available even if 
hourly emissions data are no longer reported in the future for some of 
these sources. As indicated in Table 1, the total amount of recent 
seasonal NOX emissions from the units that could potentially 
switch from part 75 monitoring approaches to non-part 75 monitoring 
approaches was approximately 15,000 tons during the 5-month ozone 
season, which by extrapolation suggests possible annual emissions of 
roughly 36,000 tons. By comparison, the most recent National Emissions 
Inventory (for 2014) indicates that for the set of NOX SIP 
Call states, the total amount of annual NOX emissions from 
all types of stationary sources--that is, not just the large EGUs and 
large non-EGU boilers and turbines currently subject to part 75 
monitoring requirements under the NOX SIP Call--was over 
2,000,000 tons, and the total amount of annual NOX emissions 
from all stationary and mobile sources was over 5,000,000 tons.\52\ 
Thus, the NOX SIP Call units potentially affected by the 
proposed amendment appear to be responsible for roughly 2% of the total 
stationary source emissions and less than 1% of the total stationary 
and mobile source emissions from NOX SIP Call states. Given 
the small percentages of the relevant overall emissions inventory 
represented by the large non-

[[Page 8436]]

EGU boilers and turbines potentially affected by the monitoring 
amendment proposed for this action, EPA expects that air quality 
modeling results and analyses of interstate ozone transport would not 
be materially affected by differences in the intra-year patterns of the 
projected hourly emissions data for these sources.
---------------------------------------------------------------------------

    \52\ See state_tier1_caps.xlsx, available at https://www.epa.gov/air-emissions-inventories/air-pollutant-emissions-trends-data (follow the link for State Average Annual Emissions 
Trend) and in the docket for this action. The total amount of 
stationary and mobile source emissions can be obtained from the 
spreadsheet by filtering column B to exclude all states except the 
21 NOX SIP Call jurisdictions, filtering column D to 
exclude ``prescribed fires'' and ``wildfires,'' filtering column E 
to exclude all pollutants except NOX, and then summing 
the 2014 emissions inventory amounts in column Y for all remaining 
line items shown. The total amount of stationary source emissions 
can be obtained in the same way after further filtering column D to 
exclude ``highway vehicles'' and ``off-highway.''
---------------------------------------------------------------------------

    With respect to the commenter's request for the identities and 
locations of units potentially affected by the proposed monitoring 
amendment--in other words, large non-EGU boilers and turbines as well 
as large EGUs that are subject to the NOX SIP Call but not 
the Acid Rain Program or a CSAPR trading program--EPA notes that the 
requested information is already publicly available in the database of 
reported part 75 emissions data accessible through the Agency's 
website.\53\ The database identifies each individual unit that has 
reported according to part 75 and provides the unit's state, county, 
latitude, and longitude. The database also indicates the regulatory 
programs for which the data have been reported, using the code 
``SIPNOX'' to indicate where a unit has reported seasonal 
NOX mass emissions data for purposes of the NOX 
SIP Call but not for purposes of the seasonal NOX trading 
programs established under CAIR, the original CSAPR, and the CSAPR 
Update. For the convenience of the commenter and others who might be 
similarly interested, EPA has extracted this information from the 
database into a spreadsheet which has been added to the docket for this 
action.\54\
---------------------------------------------------------------------------

    \53\ See https://ampd.epa.gov/ampd.
    \54\ See Existing Units Potentially Affected by the 
NOX SIP Call Monitoring Amendment (December 2018), 
available in the docket for this action. EPA acknowledges that the 
database does not differentiate between two sets of units for which 
the SIPNOX code is used: (1) Large EGUs and large non-EGU 
boilers and turbines that are described in Sec.  51.121(i)(4) and 
are potentially affected by the amendments in this action, and (2) 
other units that are not described in Sec.  51.121(i)(4) and 
therefore are not affected by the amendments in this action, but 
that nevertheless monitor according to part 75 for NOX 
SIP Call purposes pursuant to requirements in their states' SIPs. 
The spreadsheet in the docket includes only units in the first set.
---------------------------------------------------------------------------

B. Emissions Reduction Requirements

    Comment: One commenter stated it had no objection to the proposed 
revisions to the provisions expressing the NOX SIP Call's 
emissions reduction requirements to the extent that the revisions do 
not substantively adjust the states' budgets.
    Response: EPA thanks the commenter for this comment.
    Comment: One commenter agreed with EPA's objective of clarifying 
and simplifying the provisions describing the NOX SIP Call's 
emissions reduction requirements but offered suggestions for doing so 
in ways that differed in some respects from the proposed amendments. 
First, the commenter suggested replacing the terms ``budget'' and 
``NOX budget'' with a single term such as ``NOX 
ozone season budget'' both for consistency and to clarify that the 
budgets apply to seasonal rather than annual emissions. The commenter 
also suggested that EPA specify that the final budgets apply starting 
in 2007 and define the term ``ozone season'' in the regulations. 
Finally, the commenter suggested that all references to the Phase I 
budgets could be removed from the regulations because these budgets no 
longer have any substantive effect.
    Response: EPA agrees with most of the commenter's suggestions. In 
particular, EPA agrees that the regulations would be clarified by 
consistently using the term ``NOX ozone season budget'' 
throughout Sec.  202F;51.121, specifying that the final budgets apply 
starting in 2007, and documenting the definition used for the term 
``ozone season.'' Extending the commenter's suggestions, EPA believes 
the regulations would be further clarified by indicating that other 
emissions amounts described in the regulations are also ozone season 
emissions and documenting the definition used for the term ``nitrogen 
oxides'' or ``NOX.'' The specific changes from proposal that 
are being adopted in response to the commenter's suggestion are 
described in section IV of this document.
    Although EPA agrees with the commenter's observation that the Phase 
I budgets no longer have any substantive regulatory effect, EPA 
disagrees with the suggestion to remove all references to these budgets 
from the regulations. All but one of the states subject to the 
NOX SIP Call as implemented was required to adopt a SIP 
revision designed to comply with a Phase I budget, and some of the 
control measures adopted in those SIP revisions (such as measures to 
reduce emissions from cement kilns or stationary internal combustion 
engines) continue to be implemented as approved SIP provisions. While 
these control measures now address requirements to comply with the 
final budgets rather than the Phase I budgets, EPA considers it 
reasonable to retain the Phase I budgets in the regulations (and to 
specify their years of applicability) to document and facilitate 
understanding of both the state regulatory actions that originally 
adopted the measures and the EPA actions that approved the measures 
into the SIPs.

C. Baseline Emissions Inventory Table

    Comment: One commenter objected to the proposed removal of the 
baseline emissions inventory table in Sec.  51.121(g)(2)(ii), 
requesting that the table be retained (with any necessary updates) for 
use in implementing the provisions at Sec.  51.121(f)(2) that require 
enforceable limits on seasonal NOX mass emissions from large 
EGUs and large non-EGU boilers and turbines. The text of Sec.  
51.121(f)(2)(ii), which EPA has not proposed to substantively amend, 
contains the phrase ``the total NOX emissions projected for 
such sources by the State pursuant to paragraph (g) of this section.'' 
The commenter interprets this phrase as referring to amounts of 
emissions that the commenter believes either are or should be shown in 
the baseline emissions inventory table in Sec.  51.121(g)(2)(ii).
    Response: EPA disagrees with this comment, which appears to arise 
from a misinterpretation of the reference to ``paragraph (g)'' in Sec.  
51.121(f)(2)(ii). The various subparagraphs of Sec.  51.121(g) describe 
or implicate two different types of projected 2007 emissions amounts. 
The first type is the baseline pre-control emissions amounts projected 
by EPA to represent emissions absent the reductions required by the 
NOX SIP Call. The second type is the post-control emissions 
amounts projected by states to represent emissions following 
implementation of the control measures adopted in their SIPs. The table 
in Sec.  51.121(g)(2)(ii) that EPA proposed to delete was intended to 
contain \55\ the first type of emissions amount--specifically, the pre-
control emissions amounts projected by EPA for all sources \56\ in all 
sectors. In contrast, the phrase ``the total NOX emissions 
projected for such sources \57\ by the State pursuant to paragraph (g) 
of this section'' in Sec.  51.121(f)(2)(ii) refers to the second type 
of emissions amount--specifically, the post-control emissions amounts 
projected by states for their

[[Page 8437]]

large EGUs and large non-EGU boilers and turbines pursuant to Sec.  
51.121(g)(2)(iii) and used in the demonstrations required under Sec.  
51.121(g)(1). The fact that the phrase in Sec.  51.121(f)(2)(ii) refers 
to the second type of emissions amount is evident for two reasons: 
first, the relevant amounts are projected ``by the State'' and not by 
EPA, and second, the purpose of Sec.  51.121(f)(2)(ii) is to require 
enforceable mechanisms to ensure achievement of post-control emissions 
levels rather than pre-control emissions levels. Thus, the commenter's 
objection to the removal of the baseline emissions inventory table in 
Sec.  51.121(g)(2)(ii) is misplaced.
---------------------------------------------------------------------------

    \55\ As noted in the proposal, because of an error setting out 
the regulatory text for certain NOX SIP Call amendments 
finalized in 2000, the current table incorrectly shows the potential 
post-control emissions amounts that EPA projected for use in setting 
the states' amended statewide emissions budgets rather than the 
amended pre-control emissions amounts as intended. See 83 FR at 
48760 & n.48.
    \56\ The ``EGU'' and ``non-EGU'' columns of the table in Sec.  
51.121(g)(2)(ii)--both the original version showing EPA's 
projections of pre-control emissions and the incorrectly amended 
version showing EPA's projections of post-control emissions--include 
emissions amounts for all EGU and non-EGU point sources, not just 
large EGUs and large non-EGU boilers and turbines.
    \57\ The term ``such sources'' in Sec.  51.121(f)(2)(ii) refers 
to the large EGUs and large non-EGU boilers and turbines identified 
in Sec.  51.121(f)(2).
---------------------------------------------------------------------------

D. Post-NBTP Transition Requirements

    Comment: Without expressing any objection to the proposed 
clarifying amendments to the post-NBTP transition provision at Sec.  
51.121(r)(2), one commenter requested confirmation that EPA does not 
intend the requirements of the provision as revised to apply with 
regard to EGUs that participate in the CSAPR Update trading program 
under the regulations set forth at 40 CFR part 97, subpart EEEEE,\58\ 
pursuant to an approved SIP revision.
---------------------------------------------------------------------------

    \58\ The commenter similarly requests confirmation with regard 
to EGUs that participate in the original CSAPR seasonal 
NOX trading program under the regulations set forth at 40 
CFR part 97, subpart BBBBB, but this request is moot because there 
are no states subject to the NOX SIP Call with EGUs that 
continue to participate in the original CSAPR seasonal 
NOX trading program.
---------------------------------------------------------------------------

    Response: The proposed clarifying revisions to the NOX 
SIP Call post-NBTP transition provision at Sec.  51.121(r)(2) add a 
cross-reference to 40 CFR 52.38(b)(10)(ii), which is an existing 
provision of the CSAPR regulations governing SIP approvals. Under this 
provision of the CSAPR regulations, where a state has an approved full 
CSAPR SIP revision requiring certain units in the state to participate 
in a state seasonal NOX trading program integrated with the 
Federal CSAPR Update seasonal NOX trading program 
established under 40 CFR part 97, subpart EEEEE, the NOX SIP 
Call's post-NBTP transition requirements under Sec.  51.121(r)(2) are 
satisfied with regard to any of the state's large EGUs or large non-EGU 
boilers and turbines participating in that state trading program. As 
explained in the proposal,\59\ the addition of the cross reference in 
Sec.  51.121(r)(2) is not a substantive change because the approval of 
a full CSAPR SIP would produce this result even without a cross-
reference, but the cross-reference clarifies the NOX SIP 
Call regulations.
---------------------------------------------------------------------------

    \59\ 83 FR at 48760-61.
---------------------------------------------------------------------------

    Comment: Without expressing any objection to the proposed 
clarifying amendments to the post-NBTP transition provision at Sec.  
51.121(r)(2), one commenter requested that EPA further clarify the 
Rule's post-NBTP transition requirements by adding a new regulatory 
provision indicating that where a state does not require its large non-
EGU boilers and turbines to participate in the CSAPR Update trading 
program, the state must impose a cap on these units' collective 
seasonal NOX mass emissions equivalent to the portion of the 
statewide emissions budget assigned to the units under the NBTP. The 
commenter requested that EPA add the new provision to Sec.  
51.121(f)(2), the provision establishing the requirement for 
enforceable limits on seasonal NOX mass emissions from large 
EGUs and large non-EGU boilers and turbines.
    Response: This comment is outside the scope of the proposal. A 
requirement for a cap on the collective NOX mass emissions 
of each state's large non-EGU boilers and turbines does not appear in 
the existing regulatory text at Sec.  51.121 because, as discussed in 
the proposal and summarized in section II.A. of this document, the 
NOX SIP Call did not require states to control any specific 
types of sources or to adopt any specific types of control measures. 
Even where states chose to adopt control measures for large EGUs and 
large non-EGU boilers and turbines, thereby triggering requirements for 
enforceable limits on seasonal NOX mass emissions from those 
sources, the regulations provided several permissible alternative forms 
for such limits.\60\ Similarly, the post-NBTP provision at Sec.  
51.121(r)(2) does not prescribe what types of sources states must 
control to satisfy the post-NBTP transition requirements or what types 
of control measures states must employ, but simply requires each state 
with units affected under the NOX SIP Call that do not 
participate in a successor trading program to the NBTP to ``revise the 
SIP to adopt control measures that satisfy the same portion of the 
State's emission reduction requirements under [Sec.  51.121] as the 
State projected [the NBTP] would satisfy.'' The commenter's requested 
amendment would codify as a Federal requirement what may be the 
simplest way to satisfy the Rule's post-NBTP transition requirements, 
but it would also reduce states' flexibility by eliminating options to 
satisfy the post-NBTP transition requirements in other ways, and the 
reduction in flexibility would represent a substantive change to the 
existing regulations. EPA did not propose substantive changes to the 
post-NBTP transition provision and made clear that the only provision 
of the NOX SIP Call regulations being reopened for 
substantive comment was the provision concerning part 75 monitoring 
requirements for large EGUs and large non-EGU boilers and turbines.
---------------------------------------------------------------------------

    \60\ See 40 CFR 51.121(f)(2)(i)(A)-(C).
---------------------------------------------------------------------------

    Comment: Without expressing any objection to the proposed 
clarifying amendments to the post-NBTP transition provision at Sec.  
51.121(r)(2), two commenters requested that EPA identify in the 
regulations the portion of each state's statewide emissions budget 
assigned to the state's large non-EGU boilers and turbines by adding 
this information either as a new table or as an additional column in 
the table of statewide budgets in Sec.  51.121(e)(2)(i). The commenters 
suggested that inclusion of these amounts in the regulations could help 
states address their post-NBTP transition requirements. One of the 
commenters accompanied this comment with a request that EPA confirm 
``it is the EPA's intent that all required SIP elements for the 
NOX SIP Call are contained under Sec.  51.121.''
    Response: These comments are outside the scope of the proposal. The 
portions of the statewide emissions budgets assigned to various 
categories of sources do not appear in the existing regulatory text at 
Sec.  51.121 because, as discussed in the proposal and summarized in 
section II.A. of this document, the NOX SIP Call did not 
establish required post-control emissions amounts for any specific 
categories of sources. Instead, each state determined what portions of 
its post-control statewide emissions budget to assign to the specific 
categories of sources in the state, and the assignments were approved 
in separate SIP approval actions for each state.\61\ Adopting the 
state-determined, sector-specific assignments as Federal requirements 
at this time would be a substantive change to the existing regulations 
because it would reduce states' flexibility to revise their previous 
choices and select other ways of addressing their post-NBTP transition 
requirements. EPA did not propose substantive changes to the post-NBTP 
transition provision and made clear that the only provision of the 
NOX SIP Call regulations being reopened for

[[Page 8438]]

substantive comment was the provision concerning part 75 monitoring 
requirements for large EGUs and large non-EGU boilers and turbines.
---------------------------------------------------------------------------

    \61\ See, e.g., 67 FR 68542 (Nov. 12, 2002) (proposing to 
approve Virginia SIP provisions assigning portions of the statewide 
emissions budget to large EGUs and large non-EGU boilers and 
turbines); see also 68 FR 40520 (July 8, 2003) (finalizing 
approval).
---------------------------------------------------------------------------

    Comment: Without expressing any objection to the proposed 
clarifying revisions to the post-NBTP transition provision at Sec.  
51.121(r)(2), one commenter noted the proposed insertion of the words 
``or included'' into the phrase ``a State whose SIP . . . includes or 
included an emission trading program approved under [Sec.  51.121]'' 
and indicated that the commenter's interpretation of the revised 
language is that ``no action is necessary to affirm [the commenter's] 
obligation to maintain NOX SIP Call emissions control.'' The 
commenter requested that EPA clarify in this final action if the 
state's interpretation is not correct.
    Response: EPA considers this comment to be outside the scope of the 
proposal. As discussed in the proposal, the reason for inserting the 
words ``or included'' in Sec.  51.121(r)(2) was to eliminate any 
possible mistaken inference that a state's obligation to maintain 
NOX SIP Call emission controls might be contingent on 
whether its SIP currently includes trading program provisions and to 
reinforce that the Rule's emissions reductions are permanent and 
enforceable.\62\ EPA does not consider this to be a substantive change 
to the regulations.\63\ While the commenter contends that its request 
for clarification about the need for any further action regarding its 
SIP arises from the proposed insertion, the commenter has not explained 
how, if at all, its interpretation of the post-NBTP transition 
requirements might have been influenced by the proposed insertion, and 
there is no indication that the commenter's interpretation has changed 
from its interpretation before issuance of the proposal.\64\ Given the 
lack of any apparent connection between the proposed revision and the 
commenter's request for clarification, EPA interprets the comment as a 
request for a determination concerning the commenter's SIP that is 
outside the scope of the proposal. For this action, EPA did not propose 
to make any determinations regarding whether any further action is or 
is not necessary to address any specific state's post-NBTP transition 
requirements. Accordingly, EPA is not making any such state-specific 
determinations in this final action, either through express statements 
or otherwise.
---------------------------------------------------------------------------

    \62\ 83 FR at 48760-61.
    \63\ EPA notes that the continued applicability of the post-NBTP 
transition requirements following the replacement of the CAIR 
seasonal NOX trading program by the original CSAPR 
seasonal NOX trading program was discussed in the 
preamble for the CSAPR final rule. 76 FR at 48325.
    \64\ Like several other states, when the NBTP was discontinued, 
the commenter elected to include its large non-EGU boilers and 
turbines in the replacement seasonal NOX trading program 
established under CAIR, and EPA subsequently approved the removal of 
the NBTP from its SIP. The commenter is thus a state whose SIP 
``included'' a trading program approved under Sec.  51.121. The 
commenter clearly is not contending that, prior to this action, it 
believed the requirement to adopt control measures replacing the 
NBTP no longer applied to it because its SIP no longer ``includes'' 
the NBTP and that, now, the insertion of the words ``or included'' 
would cause it to understand the requirement once again applies, 
although such a contention would have internal logic and would be 
consistent with the purpose of the proposed clarification. The 
comment does not set forth the commenter's interpretation of Sec.  
51.121(r)(2) prior to this action, but if the commenter is 
contending that, prior to this action, it understood the requirement 
to adopt replacement control measures applied to it and that, now, 
the insertion of the words ``or included'' would cause it to believe 
the requirement no longer applies, that contention would be 
illogical. If the commenter is contending that the insertion of the 
words ``or included'' would alter its interpretation concerning the 
nature of the replacement control measures that can satisfy the 
post-NBTP transition requirements, that contention would also be 
illogical because with or without the added words, the post-NBTP 
transition provision does not address the nature of replacement 
control measures that states may or must adopt.
---------------------------------------------------------------------------

IV. Final Action

    For the reasons discussed in the proposal, as supplemented by the 
discussion in this document, EPA is finalizing amendments to the 
NOX SIP Call regulations at 40 CFR 51.121 and 51.122 and 
amendments to associated cross-references in the CSAPR regulations at 
40 CFR 52.38. In place of the current requirement for states to include 
provisions in their SIPs under which certain emissions sources must 
monitor their seasonal NOX mass emissions according to 40 
CFR part 75, the amended regulations will allow states to include 
alternate forms of monitoring requirements in their SIPs for 
NOX SIP Call purposes. Other amendments remove obsolete 
provisions and clarify the remaining regulations but do not 
substantively alter any current regulatory requirements.
    Descriptions of the individual proposed amendments are provided in 
sections II.B. and II.C. of this document and further discussion is 
provided in the proposal. EPA is finalizing the amendments generally as 
proposed with the following further revisions, all of which EPA 
considers to be non-substantive changes from the proposal:
     To improve clarity, the final regulatory text of Sec.  
51.121(i)(4) is being revised from the proposed amended text in two 
ways. First, the final revisions indicate that where a state chooses to 
require part 75 monitoring for some or all large EGUs and large non-EGU 
boilers and turbines for NOX SIP Call purposes, the ``full 
set of'' monitoring, recordkeeping, and reporting provisions in subpart 
H of part 75 must be required. The added words clarify that the 
amendments do not authorize states to create partial versions of the 
part 75 regulations that EPA would then have to administer on a state-
specific basis. Second, the final revisions remove a phrase indicating 
that the amended text does not create any exception to any part 75 
requirements that may apply to a source under another legal authority. 
The removed phrase is unnecessary because, on its face, the amended 
text merely gives states an option to require part 75 monitoring for 
NOX SIP Call purposes and does not create or authorize any 
exceptions to any requirements that may apply to any source under any 
legal authority. EPA believes the text of the final amendment is 
clearer and does not differ substantively from the text of the 
amendment as proposed.
     As discussed in EPA's response to comments in section 
III.B. of this document, the regulatory text expressing the 
NOX SIP Call's emissions reduction requirements is being 
further clarified by using more precise terminology and documenting the 
definitions that already apply for two important terms. The final 
revisions (1) use the standard term ``NOX ozone season 
budget'' consistently, (2) specify emissions ``during the ozone 
season'' where appropriate, (3) indicate the respective years of 
applicability for the Phase I and final emissions budgets, and (4) add 
definitions of the terms ``nitrogen oxides or NOX'' and 
``ozone season'' to Sec.  51.121. The term ``nitrogen oxides or 
NOX'' is defined as ``all oxides of nitrogen except nitrous 
oxide (N2O), reported on an equivalent molecular weight 
basis as nitrogen dioxide (NO2).'' The term ``ozone season'' 
is defined as ``the period from May 1 through September 30 of a year.'' 
The added definitions do not alter any regulatory requirements because 
they are substantively identical to the definitions that already 
explicitly apply for purposes of Sec.  51.122 and that have 
historically been used in practice for purposes of Sec.  51.121 as 
well.\65\ The additional revisions affect the regulatory text at Sec.  
51.121(a)(3), (b)(1)(i) and (iii), (e)(1), (e)(2)(i) and (ii), (f) 
introductory

[[Page 8439]]

text, (f)(2) introductory text, (f)(2)(i)(C), (g)(1), (g)(2)(i) and 
(iii), (i), and (j)(1).
---------------------------------------------------------------------------

    \65\ See 40 CFR 51.122(a); see also id. Sec.  51.50 (definition 
of ``nitrogen oxides'').
---------------------------------------------------------------------------

     Instead of being removed as proposed, the provision at 
Sec.  51.121(d)(2) concerning procedural requirements for SIP 
submissions is being revised to incorporate the updated procedural 
requirements for SIP submissions at 40 CFR 51.103. In the proposal,\66\ 
EPA stated the intent for the completeness and format requirements in 
Sec.  51.103 to apply to any future SIP submissions under Sec.  51.121. 
The final revision makes such applicability explicit and is consistent 
with several other provisions of Sec.  51.121 that similarly 
incorporate requirements set forth in other sections of 40 CFR part 51.
---------------------------------------------------------------------------

    \66\ 83 FR at 48761.
---------------------------------------------------------------------------

     An additional editorial revision is being made to the text 
of Sec.  51.121(k)(2). The revision clarifies the regulations by 
standardizing citation formats.
    A redline-strikeout document showing the text of 40 CFR 51.121 and 
51.122 with the amendments adopted in this action, including all the 
proposed amendments to the NOX SIP Call regulations with the 
further revisions just described, is available in the docket for this 
action.
    The amendments finalized in this action are effective immediately 
upon publication of the action in the Federal Register. This final 
action is not subject to requirements specifying a minimum period 
between publication and effectiveness under either Congressional Review 
Act (CRA) section 801(a)(3), 5 U.S.C. 801(a)(3), or Administrative 
Procedure Act (APA) section 553(d), 5 U.S.C. 553(d).
    CRA section 801(a)(3) generally prohibits a ``major rule'' from 
taking effect earlier than 60 days after the rule is published in the 
Federal Register. Generally, under CRA section 804(2), 5 U.S.C. 804(2), 
a major rule is a rule that the Office of Management and Budget (OMB) 
finds has resulted in or is likely to result in (1) an annual effect on 
the economy of $100 million or more, (2) major cost or price increases, 
or (3) other significant adverse economic effects. This action is not a 
major rule for CRA purposes.
    As discussed in section VI.M. of this document, EPA is issuing the 
amendments under CAA section 307(d). This provision does not include 
requirements governing the effective date of a rule promulgated under 
it and, accordingly, EPA has discretion in establishing the effective 
date. While APA section 553(d) generally provides that rules may not 
take effect earlier than 30 days after they are published in the 
Federal Register, CAA section 307(d)(1) clarifies that ``[t]he 
provisions of [APA] section 553 . . . shall not, except as expressly 
provided in this section, apply to actions to which this subsection 
applies.'' Thus, APA section 553(d) does not apply to the amendments. 
Nevertheless, in making this final action effective immediately upon 
publication, EPA has considered the purposes underlying APA section 
553(d). The primary purpose of the prescribed 30-day waiting period is 
to give affected parties a reasonable time to adjust their behavior and 
prepare before a final rule takes effect. The amendments made in this 
action do not impose any new regulatory requirements and therefore do 
not necessitate time for affected sources to adjust their behavior or 
otherwise prepare for implementation. Further, APA section 553(d) 
expressly allows an effective date earlier than 30 days after 
publication for a rule that ``grants or recognizes an exemption or 
relieves a restriction.'' This action relieves an existing restriction 
and allows EPA to approve SIPs with more flexible monitoring 
requirements, which in turn could lead to reduced monitoring costs for 
certain sources. Consequently, making the amendments effective 
immediately upon publication of the action is consistent with the 
purposes of APA section 553(d).

V. Impacts of the Amendments

    The only amendment being finalized in this action that 
substantively alters existing regulatory requirements is the amendment 
allowing states to revise their SIPs, for NOX SIP Call 
purposes only, to establish monitoring requirements other than part 75 
monitoring requirements. The amendments do not change any of the Rule's 
existing regulatory requirements related to statewide emissions budgets 
or enforceable mass emissions limits for large EGUs and large non-EGU 
boilers and turbines. Accordingly, EPA expects that the amendments will 
have no impact on emissions or air quality. However, EPA does expect 
that the amendment to the Rule's monitoring requirements will 
ultimately allow some sources to reduce their monitoring costs because 
of alternate monitoring requirements established in SIP revisions 
submitted and approved for their states. Because states, not EPA, will 
decide whether to revise the monitoring requirements in their SIPs and 
because EPA lacks complete information on the remaining monitoring 
requirements that the sources would face, there is considerable 
uncertainty concerning the amount of monitoring cost reductions that 
may be facilitated by this action, and EPA did not present a 
quantitative estimate of potential monitoring cost reductions in the 
proposal. For purposes of the final action, based in part on improved 
information obtained through comments, EPA has estimated a range of 
potential annual monitoring cost reductions from $1.2 million to $3.3 
million, with a midpoint estimate of $2.25 million, as further 
discussed below. Given the absence of any change in emissions or air 
quality, there would be no change in the public health and 
environmental benefits attributable to the NOX SIP Call's 
emissions reduction requirements, and the likely reductions in 
monitoring costs therefore are expected to constitute positive net 
benefits from this action.
    As of December 2018, EPA's records indicate that there are 
approximately 315 existing large EGUs and large non-EGU boilers and 
turbines in the NOX SIP Call region that could potentially 
be affected by the monitoring amendment if all states were to revise 
their SIPs.\67\ To estimate how many of these potentially affected 
existing units may ultimately face alternate monitoring requirements 
made possible by the monitoring amendment in this action, EPA is 
relying on information obtained from states' comments. Six states 
submitted comments expressing support for the proposed monitoring 
amendment.\68\ While these comments do not in any way obligate the 
states to submit SIP revisions with alternate monitoring requirements, 
and additional states that did not submit comments could also choose to 
submit SIP revisions, EPA believes that the comments provide a 
reasonable basis for assuming, solely for purposes of developing an 
estimate of this action's impacts, that the 102 existing units in these 
six states will ultimately face alternate monitoring requirements of 
some kind.\69\ According to the monitoring plans for these units, 34 
units use both gas concentration CEMS

[[Page 8440]]

and stack gas flow rate CEMS, 35 units use gas concentration CEMS but 
not stack gas flow rate CEMS, and 33 units use non-CEMS methodologies. 
For purposes of estimating potential monitoring cost reductions, EPA 
has focused on the units currently using CEMS because, as noted in the 
proposal and in section II.B. of this document, EPA expects that units 
already using non-CEMS methodologies under part 75 would experience 
little or no reduction in monitoring costs from alternate monitoring 
requirements.
---------------------------------------------------------------------------

    \67\ The spreadsheet referenced in note 54 supra identifies 317 
potentially affected existing units. As noted in section II.B. of 
this document, in the proposal for this action EPA indicated that 
there were approximately 310 potentially affected existing units. 
Several additional units started reporting emissions for 
NOX SIP Call purposes in 2018.
    \68\ The six states are Indiana, Michigan, North Carolina, Ohio, 
South Carolina, and West Virginia.
    \69\ The 102 units are the existing units identified in the 
spreadsheet referenced in note 54 supra for these six states. While 
any new units in these states that otherwise would have been 
required to use CEMS methodologies for NOX SIP Call 
purposes could also experience monitoring cost reductions, EPA 
believes it is reasonable to ignore possible new units in preparing 
this estimate due to the larger numbers of existing units.
---------------------------------------------------------------------------

    To represent the alternate monitoring requirements that the units 
currently using CEMS could face in a manner that reflects the 
substantial uncertainty on this issue, EPA has used a range of 
assumptions. Specifically, to estimate the low end of the range, EPA 
has assumed that the only change from current requirements is that the 
34 units currently using both gas concentration CEMS and stack gas flow 
rate CEMS will discontinue the use of stack gas flow rate CEMS. EPA 
considers this assumption to be reasonable for purposes of estimating 
potential monitoring cost reductions because requirements to use stack 
gas flow rate CEMS are relatively uncommon in non-part 75 monitoring 
regulations. EPA also believes the units currently using stack gas flow 
rate CEMS are more likely than other potentially affected units to 
continue to be subject to requirements to use gas concentration CEMS 
because many of these units combust solid fuel and consequently may 
have triggered emission control requirements and associated emissions 
monitoring requirements under other regulations. To estimate the high 
end of the range, EPA has assumed that in addition to the change just 
described, the 35 units currently using only gas concentration CEMS 
will switch to a non-CEMS methodology. While it is possible that some 
of these units may also face continued requirements to use gas 
concentration CEMS under other regulations, EPA believes the likelihood 
that these units, none of which combust solid fuel, would be eligible 
to use non-CEMS methodologies is greater than for the units that 
currently use both gas concentration CEMS and stack gas flow rate CEMS.
    To estimate the monitoring cost reductions associated with the 
assumed range of changes in monitoring requirements, EPA has used the 
cost estimates for the various part 75 monitoring methodologies 
contained in the information collection request (ICR) renewal prepared 
in conjunction with this action for purposes of the Paperwork Reduction 
Act, 44 U.S.C. 3501 et seq.\70\ Based on the cost estimates in the ICR 
renewal, EPA has estimated that the potential annual cost reduction 
from discontinuing the use of stack gas flow rate CEMS--including 
reductions in labor costs, non-labor operating and maintenance costs 
(including contractor costs), and annualized capital costs--is 
approximately $35,000 per unit, while the analogous potential annual 
cost reduction from discontinuing the use of gas concentration CEMS is 
approximately $60,000 per unit.\71\ Multiplying these per-unit amounts 
by the respective numbers of units yields an estimated range of 
potential annual monitoring cost reductions from $1.2 million to $3.3 
million.\72\ The midpoint of this range is a potential reduction in 
annual monitoring costs of $2.25 million.
---------------------------------------------------------------------------

    \70\ See section VI.C. infra.
    \71\ See Information Collection Request Renewal for the 
NOX SIP Call: Supporting Statement (September 2018) at 12 
(Table 6-2), available in the docket for this action. The $35,000 
estimate is the rounded difference between the sum of the amounts in 
the labor, O&M, and annualized capital cost columns on line 6(a) and 
the sum of the amounts in the same columns on line 6(b). The $60,000 
estimate is the rounded difference from the same calculation 
performed using the amounts on lines 6(b) and 6(c) instead.
    \72\ Calculation of low end of range: 34 units x $35,000 per 
unit = $1.2 million.
    Calculation of high end of range: 35 units x $60,000 per unit + 
$1.2 million = $3.3 million.
---------------------------------------------------------------------------

VI. Statutory and Executive Order Reviews

    Additional information about these statutes and executive orders 
can be found at https://www.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 not a significant regulatory action and was 
therefore not submitted to OMB for review.

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

    This action is considered an Executive Order 13771 deregulatory 
action. This final rule provides meaningful burden reduction by 
allowing states to establish lower-cost monitoring requirements in 
their SIPs for some sources as alternatives to part 75 monitoring 
requirements. Because states, not EPA, will decide whether to revise 
the monitoring requirements in their SIPs and because EPA lacks 
complete information on the remaining monitoring requirements that the 
sources would face, there is considerable uncertainty regarding the 
amount of monitoring cost reductions that may occur, but EPA has 
quantified an estimated range in section V of this document. In 
addition, the proposal's qualitative discussion of the potential 
monitoring cost reductions \73\ is summarized in section II.B. of this 
document.
---------------------------------------------------------------------------

    \73\ 83 FR at 48761-62.
---------------------------------------------------------------------------

C. Paperwork Reduction Act

    This action does not impose any new information collection burden 
under the Paperwork Reduction Act. OMB has previously approved the 
information collection activities contained in the existing regulations 
and has assigned OMB control number 2060-0445. However, to reflect the 
amendment allowing states to establish potentially lower-cost 
monitoring requirements for some sources as alternatives to the current 
part 75 monitoring requirements, EPA submitted an information 
collection request (ICR) renewal to OMB in conjunction with the 
proposal for this action. The ICR document prepared by EPA, which has 
been assigned EPA ICR number 1857.08, can be found in the docket for 
this action. None of the comments that EPA received during the public 
comment period for the proposal addressed the ICR renewal.
    Like the current ICR, the ICR renewal reflects the information 
collection burden and costs associated with part 75 monitoring 
requirements for sources that are subject to part 75 monitoring 
requirements under the SIP revisions addressing states' NOX 
SIP Call obligations and that are not subject to part 75 monitoring 
requirements under the Acid Rain Program or a CSAPR trading program. 
The ICR renewal is generally unchanged from the current ICR except that 
the renewal reflects projected decreases in the numbers of sources that 
would perform part 75 monitoring for NOX SIP Call purposes 
based on an assumption (made only for purposes of estimating 
information collection burden and costs for the ICR renewal) that, over 
the course of the 3-year renewal period, some states will revise their 
SIPs to replace part 75 monitoring requirements for some sources with 
lower-cost monitoring requirements. As under the current ICR, all 
information collected from sources under the ICR renewal will be 
treated as public information.
    Respondents/affected entities: Fossil fuel-fired boilers and 
stationary combustion turbines that have heat input capacities greater 
than 250 mmBtu/hr or serve electricity generators

[[Page 8441]]

with nameplate capacities greater than 25 MW and that are not subject 
to part 75 monitoring requirements under another program.
    Respondents' obligation to respond: Mandatory if elected by the 
state (40 CFR 51.121(i)(4) as amended).
    Estimated number of respondents: 340 (average over 2019-2021 
renewal period).
    Frequency of response: Quarterly, occasionally.
    Total estimated burden: 131,945 hours (per year). Burden is defined 
at 5 CFR 1320.3(b).
    Total estimated cost: $19,143,004 (per year), includes $8,256,087 
annualized capital or operation & maintenance costs.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9. When OMB approves 
this ICR renewal, the Agency will announce that approval in the Federal 
Register.

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, 5 U.S.C. 601-612. 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 does not directly regulate any entity, but simply allows 
states to establish potentially lower-cost monitoring requirements for 
some sources and generally streamlines existing regulations. EPA has 
therefore concluded that this action will either relieve or have no net 
regulatory burden for all affected 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 allows states to establish 
potentially lower-cost monitoring requirements for some sources and 
generally streamlines existing regulations.

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 allows states to establish potentially lower-cost 
monitoring requirements for some sources and generally streamlines 
existing regulations.

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 
allows states to establish potentially lower-cost monitoring 
requirements for some sources and generally streamlines existing 
regulations. Thus, Executive Order 13175 does not apply to this action.

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

    EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that 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 does not concern an environmental health risk or 
safety risk. This action simply allows states to establish potentially 
lower-cost monitoring requirements for some sources and generally 
streamlines existing regulations.

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

    This action is not subject to Executive Order 13211 because it is 
not a significant regulatory action under Executive Order 12866.

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

    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 allows states to establish potentially 
lower-cost monitoring requirements for some sources and generally 
streamlines existing regulations. Consistent with Executive Order 12898 
and EPA's environmental justice policies, EPA considered effects on 
low-income populations, minority populations, and indigenous peoples 
while developing the original NOX SIP Call. The process and 
results of that consideration are described in the Regulatory Impact 
Analysis for the NOX SIP Call.

L. Congressional Review Act

    This action is subject to the Congressional Review Act, and EPA 
will submit a rule report to each House of the Congress and to the 
Comptroller General of the United States. This action is not a ``major 
rule'' as defined by 5 U.S.C. 804(2).

M. Determinations Under CAA Section 307(b) and (d)

    CAA section 307(b)(1), 42 U.S.C. 7607(b)(1), indicates which United 
States Courts of Appeals 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 U.S. Court of Appeals for the District of 
Columbia Circuit (D.C. Circuit) if (i) the Agency action consists of 
``nationally applicable regulations promulgated, or final action taken, 
by the Administrator,'' or (ii) the 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.'' This 
action amends existing regulations that apply to 20 states and the 
District of Columbia, and thus the action applies to the same 21 
jurisdictions. The existing regulations were promulgated to address 
interstate transport of air pollution across the eastern half of the 
nation and the resulting emissions reductions have been relied on as a 
basis for actions redesignating areas in at least 20 states to 
attainment with one or more NAAQS.

[[Page 8442]]

The states affected under the regulations and relying on the resulting 
emissions reductions are located in multiple EPA Regions and Federal 
judicial circuits. Previous final actions promulgating and amending the 
existing regulations were nationally applicable and reviewed in the 
D.C. Circuit. For these reasons, the Administrator determines that this 
final action 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 this final action must be filed in the D.C. Circuit within 60 
days from the date this final action is published in the Federal 
Register.
    CAA section 307(d), 42 U.S.C. 7607(d), contains rulemaking and 
judicial review provisions that apply to certain EPA actions under the 
CAA including, under section 307(d)(1)(V), ``such other actions as the 
Administrator may determine.'' In accordance with section 307(d)(1)(V), 
the Administrator determines that the provisions of section 307(d) 
apply to this final action. EPA has complied with the procedural 
requirements of section 307(d) during the course of this rulemaking.

List of Subjects

40 CFR Part 51

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

40 CFR Part 52

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

    Dated: February 26, 2019.
Andrew R. Wheeler,
Acting Administrator.

    For the reasons stated in the preamble, parts 51 and 52 of chapter 
I of title 40 of the Code of Federal Regulations are amended as 
follows:

PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF 
IMPLEMENTATION PLANS

0
1. The authority citation for part 51 continues to read as follows:

    Authority: 23 U.S.C. 101; 42 U.S.C. 7401-7671q.

Subpart G--Control Strategy


Sec.  51.121  [Amended]

0
2. Section 51.121 is amended by:
0
 a. Revising the section heading;
0
 b. Removing and reserving paragraph (a)(2);
0
 c. Revising paragraph (a)(3);
0
 d. In paragraph (b)(1) introductory text, removing the text ``section, 
the'' and adding in its place the text ``section, each'';
0
 e. In paragraph (b)(1)(i), adding the words ``during the ozone 
season'' after the words ``NOX emissions'', adding the words 
``applicable NOX ozone season'' before the word ``budget'', 
and removing the text ``(except as provided in paragraph (b)(2) of this 
section),'' and adding in its place a semicolon;
0
f. In paragraph (b)(1)(ii), removing the period and adding in its place 
``; and'';
0
 g. In paragraph (b)(1)(iii), adding the words ``NOX ozone 
season'' before the word ``budget'';
0
 h. Removing and reserving paragraph (b)(2);
0
i. In paragraph (c)(1), removing the text ``With respect to the 1-hour 
ozone NAAQS:'';
0
 j. In paragraph (c)(2), removing the text ``With respect to the 1-hour 
ozone NAAQS, the portions of Missouri, Michigan, and Alabama'' and 
adding in its place the text ``The portions of Alabama, Michigan, and 
Missouri'';
0
k. Removing and reserving paragraph (d)(1);
0
 l. Revising paragraph (d)(2);
0
 m. In paragraph (e)(1), adding the words ``ozone season'' before the 
word ``budget'';
0
 n. Revising paragraph (e)(2)(i);
0
o. In paragraph (e)(2)(ii)(A), adding the words ``ozone season'' before 
the word ``budget'';
0
p. In paragraph (e)(2)(ii)(B), removing the text ``De Kalb'' and adding 
in its place the text ``DeKalb'';
0
 q. In paragraph (e)(2)(ii)(E), removing the text ``St. Genevieve,'' 
and after the text ``St. Louis City,'' adding the text ``Ste. 
Genevieve,'';
0
 r. Removing paragraphs (e)(3), (4), and (5);
0
 s. In paragraphs (f) introductory text and (f)(2) introductory text, 
adding the words ``ozone season'' before the word ``budget'';
0
 t. In paragraph (f)(2)(i)(B), removing the words ``mass 
NOX'' and adding in their place the words ``NOX 
mass'';
0
u. In paragraph (f)(2)(i)(C), removing ``paragraphs (f)(2)(i)(A) or 
(f)(2)(i)(B)'' and adding in its place ``paragraph (f)(2)(i)(A) or 
(B)'' and adding the words ``ozone season'' before the word ``budget'';
0
 v. In paragraph (f)(2)(ii), removing the text ``(b)(1) (i)'' and 
adding in its place the text ``(b)(1)(i)'';
0
w. In paragraph (g)(1), adding the words ``ozone season'' before the 
word ``budget'';
0
x. In paragraph (g)(2)(i), adding the words ``during the ozone season'' 
after the words ``mass emissions'', adding the words ``ozone season'' 
before the word ``budget'', and removing the text ``as set forth for 
the State in paragraph (g)(2)(ii) of this section,'';
0
y. Removing and reserving paragraph (g)(2)(ii);
0
 z. In paragraph (g)(2)(iii), adding the words ``during the ozone 
season'' after the words ``mass emissions'';
0
aa. In paragraph (h), removing the words ``of this part'';
0
bb. In paragraph (i) introductory text, adding the words ``ozone 
season'' before the word ``budget'';
0
 cc. In paragraphs (i)(2) and (3), removing the words ``of this part'';
0
 dd. Revising paragraphs (i)(4) and (5);
0
 ee. In paragraph (j)(1), adding the words ``ozone season'' before the 
word ``budget'';
0
 ff. In paragraph (k)(2), removing the text ``CAA'' and adding in its 
place the text ``CAA, 42 U.S.C. 7414'';
0
 gg. In paragraphs (l) and (m), removing the phrase ``of this part'' 
everywhere it appears;
0
 hh. In paragraph (n), removing the text ``Sec.  52.31(c) of this 
part'' and adding in its place the text ``40 CFR 52.31(c)'' and 
removing the text ``Sec.  52.31 of this part'' and adding in its place 
the text ``40 CFR 52.31'';
0
 ii. In paragraph (o), removing the words ``of this part'';
0
 jj. Removing and reserving paragraphs (p) and (q); and
0
 kk. Revising paragraph (r).
    The revisions read as follows:


Sec.  51.121  Findings and requirements for submission of State 
implementation plan revisions relating to emissions of nitrogen oxides.

    (a) * * *
    (3) As used in this section, these terms shall have the following 
meanings:
    Nitrogen oxides or NOX means all oxides of nitrogen except nitrous 
oxide (N2O), reported on an equivalent molecular weight 
basis as nitrogen dioxide (NO2).
    Ozone season means the period from May 1 to September 30 of a year.
    Phase I SIP submission means a SIP revision submitted by a State on 
or before October 30, 2000 in compliance with paragraph (b)(1)(ii) of 
this section to limit projected NOX emissions during the 
ozone season from sources in the

[[Page 8443]]

relevant portion or all of the State, as applicable, to no more than 
the State's Phase I NOX ozone season budget under paragraph 
(e) of this section.
    Phase II SIP submission means a SIP revision submitted by a State 
in compliance with paragraph (b)(1)(ii) of this section to limit 
projected NOX emissions during the ozone season from sources 
in the relevant portion or all of the State, as applicable, to no more 
than the State's final NOX ozone season budget under 
paragraph (e) of this section.
* * * * *
    (d) * * *
    (2) Each SIP submission under this section must comply with Sec.  
51.103 (regarding submission of plans).
    (e) * * *
    (2)(i) The State-by-State amounts of the Phase I and final 
NOX ozone season budgets, expressed in tons, are listed in 
Table 1 to this paragraph (e)(2)(i):

     Table 1 to Paragraph (e)(2)(i)--State NOX Ozone Season Budgets
------------------------------------------------------------------------
                                    Phase I NOX ozone   Final NOX ozone
                                      season budget      season budget
               State                   (2004-2006)         (2007 and
                                                          thereafter)
------------------------------------------------------------------------
Alabama...........................            124,795            119,827
Connecticut.......................             42,891             42,850
Delaware..........................             23,522             22,862
District of Columbia..............              6,658              6,657
Illinois..........................            278,146            271,091
Indiana...........................            234,625            230,381
Kentucky..........................            165,075            162,519
Maryland..........................             82,727             81,947
Massachusetts.....................             85,871             84,848
Michigan..........................            191,941            190,908
Missouri..........................  .................             61,406
New Jersey........................             95,882             96,876
New York..........................            241,981            240,322
North Carolina....................            171,332            165,306
Ohio..............................            252,282            249,541
Pennsylvania......................            268,158            257,928
Rhode Island......................              9,570              9,378
South Carolina....................            127,756            123,496
Tennessee.........................            201,163            198,286
Virginia..........................            186,689            180,521
West Virginia.....................             85,045             83,921
------------------------------------------------------------------------

* * * * *
    (i) * * *
    (4) If the revision contains measures to control fossil fuel-fired 
NOX sources serving electric generators with a nameplate 
capacity greater than 25 MWe or boilers, combustion turbines or 
combined cycle units with a maximum design heat input greater than 250 
mmBtu/hr, then the revision may require some or all such sources to 
comply with the full set of monitoring, recordkeeping, and reporting 
provisions of 40 CFR part 75, subpart H. A State requiring such 
compliance authorizes the Administrator to assist the State in 
implementing the revision by carrying out the functions of the 
Administrator under such part.
    (5) For purposes of paragraph (i)(4) of this section, the term 
``fossil fuel-fired'' has the meaning set forth in paragraph (f)(3) of 
this section.
* * * * *
    (r)(1) Notwithstanding any provisions of subparts A through I of 40 
CFR part 96 and any State's SIP to the contrary, with regard to any 
ozone season that occurs after September 30, 2008, the Administrator 
will not carry out any of the functions set forth for the Administrator 
in subparts A through I of 40 CFR part 96 or in any emissions trading 
program provisions in a State's SIP approved under this section.
    (2) Except as provided in 40 CFR 52.38(b)(10)(ii), a State whose 
SIP is approved as meeting the requirements of this section and that 
includes or included an emissions trading program approved under this 
section must revise the SIP to adopt control measures that satisfy the 
same portion of the State's NOX emissions reduction 
requirements under this section as the State projected such emissions 
trading program would satisfy.


Sec.  51.122  [Amended]

0
 3. Section 51.122 is amended by:
0
 a. In paragraph (c)(1)(ii), removing the text ``pursuant to a trading 
program approved under Sec.  51.121(p) or'';
0
 b. In paragraph (e), removing the first sentence;
0
 c. In paragraph (f), removing the paragraph heading; and
0
 d. Removing the second paragraph (g).

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

Subpart A--General Provisions


Sec.  52.38  [Amended]

0
 5. In Sec.  52.38, paragraphs (b)(8)(ii), (b)(8)(iii)(A)(2), 
(b)(9)(ii), and (b)(9)(iii)(A)(2) are amended by removing the text 
``Sec.  51.121(p)'' and adding in its place the text ``Sec.  51.121''.

[FR Doc. 2019-03854 Filed 3-7-19; 8:45 am]
 BILLING CODE 6560-50-P


