existing Renewable Portfolio Standard (RPS) and the proposed Clean and
Renewable Energy Standard (CARES), and by capping and reducing
emissions through the Regional Greenhouse Gas Initiative
(RGGI).87 88 Maryland's RPS requires Maryland electric
utilities to purchase increasingly large proportions of Maryland's
electricity from renewable energy sources like solar, wind, hydropower,
and qualifying biomass, with a current RPS goal of 50% clean
electricity by 2030 and 100% clean electricity by 2040. Maryland states
that these goals rely on both renewable energy and additional zero- and
low-carbon electricity sources to meet that goal where most cost-
effective, including Maryland solar power beyond current RPS
requirements, new efficient CHP systems in Maryland buildings, new
nuclear power, and natural gas or qualifying biomass power plants with
carbon capture and storage. Maryland further states that, although RGGI
is designed to reduce carbon dioxide emissions, other benefits in terms
of NOX and SO2 are realized through energy
efficiency promotion, CHP deployment, and additional deployment of
renewable energy sources, including offshore wind power and community
solar generation.\89\ Maryland therefore concludes that it is meeting
Ask 6.
---------------------------------------------------------------------------

    \84\ See Appendix 7, ``MANE-VU Regional Haze Consultation Report
(July 27, 2018),'' of the MD Regional Haze SIP for the Second
Implementation Period 2018-2028 (February 8, 2022).
    \85\ See docket document, ``MDE The 2030 Greenhouse Gas
Emissions Reduction Act (GGRA) Plan (February 19, 2021)''.
    \86\ mde.maryland.gov/programs/air/ClimateChange/Pages/Greenhouse-Gas-Emissions-Reduction-Act-(GGRA)-Plan.aspx.
    \87\ www.rggi.org/.
    \88\ www.rggiprojectseries.org/.
    \89\ See Section 2.5.6 of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

2. The EPA's Evaluation of Maryland's Response to the Six MANE-VU Asks
and Compliance With Sec.  51.308(f)(2)(i)
    The EPA is proposing to find that Maryland has satisfied the
requirements of 40 CFR 51.308(f)(2)(i) related to evaluating sources
and determining the emission reduction measures that are necessary to
make reasonable progress by considering the four statutory factors. We
are proposing to find that Maryland has satisfied the four-factor
analysis requirement through its analysis and actions to address MANE-
VU Ask 2 and Ask 5. We also propose to find that Maryland reasonably
concluded that it satisfied all six Asks.
    As explained above, Maryland relied on MANE-VU's technical analyses
and framework (i.e., the Asks) to select sources and form the basis of
its long-term strategy. MANE-VU conducted an inventory analysis to
identify the source sectors that produced the greatest amount of
SO2 and NOX emissions in 2011; inventory data
were also projected to 2018. Based on this analysis, MANE-VU identified
the top-emitting sectors for each of the two pollutants, which for
SO2 include coal-fired EGUs, industrial boilers, oil-fired
EGUs, and oil-fired area sources including residential, commercial, and
industrial sources. Major-emitting sources of NOX include
on-road vehicles, non-road vehicles, and EGUs.\90\ The RPO's
documentation explains that ``[EGUs] emitting SO2 and
NOX and industrial point sources emitting SO2
were found to be sectors with high emissions that warranted further
scrutiny. Mobile sources were not considered in this analysis because
any ask concerning mobile sources would be made to EPA and not during
the intra-RPO and inter-RPO consultation process among the states and
tribes.'' \91\ EPA proposes to find that Maryland reasonably evaluated
the two pollutants--SO2 and NOX--that currently
drive visibility impairment within the MANE-VU region and that it
adequately explained and supported its decision to focus on these two

pollutants through its reliance on the MANE-VU technical analyses cited
in its submission.
---------------------------------------------------------------------------

    \90\ See Appendix 3 ``MANE-VU Updated Q/d*C Contribution
Assessment (MANE-VU, April 2016).
    \91\ See docket documents, ``MANE-VU Inter-Regional Ask Final 8-
25-2017 (August 25, 2017)'' and MANE-VU Intra-Regional Ask Final 8-
25-2017 (August 25, 2017).
---------------------------------------------------------------------------

    Section 51.308(f)(2)(i) requires states to evaluate and determine
the emission reduction measures that are necessary to make reasonable
progress by applying the four statutory factors to sources in a control
analysis. As explained previously, the MANE-VU Asks are a mix of
measures for sectors and groups of sources identified as reasonable for
states to address in their regional haze plans. While MANE-VU
formulated the Asks to be ``reasonable emission reduction strategies''
to control emissions of visibility impairing pollutants,\92\ EPA
believes that Maryland's responses to two of the Asks, in particular,
engage with the requirement that states determine the emission
reduction measures that are necessary to make reasonable progress
through consideration of the four factors. As laid out in further
detail below, the EPA is proposing to find that MANE-VU's four-factor
analysis conducted to support the emission reduction measures in Ask 3
(ultra-low sulfur fuel oil Ask), in conjunction with Maryland's
supplemental analysis and explanation of how it has complied with Ask 2
(perform four-factor analyses for sources with potential for >=3.0
Mm-1 impacts) satisfy the requirement of 40 CFR
51.308(f)(2)(i). The emission reduction measures that are necessary to
make reasonable progress must be included in the long-term strategy,
i.e., in Maryland's SIP. 40 CFR 51.308(f)(2).
---------------------------------------------------------------------------

    \92\ Id.
---------------------------------------------------------------------------

    Maryland asserted that it satisfies Ask 1 because it has SIP-
approved regulations applicable to EGU boilers that include annual
emission limits for both NOX\93\ \94\ and
SO2,\95\ and require the most effective use of emission
control technologies on a year-round basis. Maryland also claimed
additional SIP-approved SO2 emission reductions as a result
of the consent order for the Anne Arundel County and Baltimore County
SO2 nonattainment area for the 2010 SO2
NAAQS.\96\ As a reminder, MANE-VU Ask 1 requests that states ``ensure
the most effective use of control technologies on a year-round basis to
consistently minimize emissions of haze precursors, or obtain
equivalent alternative emission reductions'' at EGUs ``with a nameplate
capacity larger than or equal to 25 MW with already installed
NOX and/or SO2 controls''.\97\ Therefore, EPA
finds it reasonable to conclude that Maryland has satisfied Ask 1.
---------------------------------------------------------------------------

    \93\ See COMAR 26.11.27, ``Emission Limitations for Power
Plants'', also at www.epa.gov/sips-md/maryland-sip-emission-limitations-power-plants.
    \94\ See COMAR 26.11.40, ``NOX Ozone Season Emission
Caps for Non-trading Large NOX Units'' also at
www.epa.gov/sips-md/maryland-sip-nox-ozone-season-emission-caps-non-trading-large-nox-units.
    \95\ See COMAR 26.11.27, ``Emission Limitations for Power
Plants'', also at www.epa.gov/sips-md/maryland-sip-emission-limitations-power-plants.
    \96\ See 87 FR 66086, November 2, 2022, and docket documents
``MDE SO2 2010 NAAQS SIP for Baltimore and Anne Arundel
NA (January 31, 2020)'', and ``MDE SO2 2010 NAAQS SIP for
Baltimore and Anne Arundel NA (January 31, 2020)--Appendix B--
Consent Orders, Permits, and Plan Approvals''.
    \97\ See Appendix 7, ``MANE-VU Regional Haze Consultation Report
(July 27, 2018),'' of the MD Regional Haze SIP for the Second
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    Ask 2 addresses the sources MANE-VU determined have the potential
for larger than, or equal to, 3.0 Mm-1 visibility impact at
any MANE-VU Class I area; the Ask requests MANE-VU states to conduct
four-factor analyses for the specified sources within their borders.
This Ask explicitly engages with the statutory and regulatory
requirement to determine reasonable progress based on the four factors;
MANE-VU considered it ``reasonable to have the greatest contributors to
visibility impairment conduct a four-factor analysis that would
determine whether emission control measures should be pursued and what
would be reasonable for each source.'' \98\
---------------------------------------------------------------------------

    \98\ See Appendix 7, ``MANE-VU Regional Haze Consultation Report
(July 27, 2018),'' of the MD Regional Haze SIP for the Second
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    As an initial matter, EPA does not necessarily agree that 3.0
Mm-1 visibility impact is a reasonable threshold for source
selection. The RHR recognizes that, due to the nature of regional haze
visibility impairment, numerous and sometimes relatively small sources
may need to be selected and evaluated for control measures in order to
make reasonable progress. See 2021 Clarifications Memo at 4.\99\ As
explained in the 2021 Clarifications Memo, while states have discretion
to choose any source selection threshold that is reasonable, ``[a]
state that relies on a visibility (or proxy for visibility impact)
threshold to select sources for four-factor analysis should set the
threshold at a level that captures a meaningful portion of the state's
total contribution to visibility impairment to Class I areas.'' 2021
Memo at 3.\100\ In this case, the 3.0 Mm-1 threshold
identified only two sources in Maryland (and only 22 across the entire
MANE-VU region), indicating that they may be unreasonably high.
Maryland selected all sources identified by MANE-VU as being above
MANE-VU's 3.0 Mm-1 threshold for four-factor analysis.
---------------------------------------------------------------------------

    \99\ See docket document, ``EPA 2021 Regional Haze
Clarifications Memo (July 8, 2021)''.
    \100\ Id.
---------------------------------------------------------------------------

    MANE-VU identified one unit at the Herbert A. Wagner Generating
Facility,\101\ a coal-fired EGU, and two units at Verso Luke Paper
Company,\102\ a large industrial source, as having a greater than 3.0
Mm-1 visibility impact and thus meeting the threshold for
four-factor analyses. Maryland's SIP submittal indicates that it sent a
letter requesting a four-factor analysis to Herbert A. Wagner
Facility's owner/operator,\103\ who subsequently announced that it
would eliminate the use of coal at the facility. This was codified into
a consent order between Maryland and the owner/operator to cease coal
combustion at the facility by January 1, 2026.\104\ Maryland has
requested that the entire consent order be incorporated into Maryland's
SIP and made federally enforceable upon EPA's approval; \105\ EPA
intends to incorporate this consent order into the Maryland SIP by
reference as a source-specific requirement upon final approval of this
proposed rulemaking. Maryland's subsequent four-factor analysis for the
facility concluded that no further control was necessary. Regarding the
Verso Luke Paper industrial source, Maryland stated that this facility
ceased operations, shut down and surrendered their existing air permits
as of May 7, 2020.\106\ Informed in part by this development, EPA found
that the area was monitoring air quality consistent with achieving the
2010 1-Hour SO2 Primary NAAQS. See 87 FR 66086, November 2,
2022. Maryland therefore concluded that no further action was necessary
for this facility. Given that no other sources in Maryland met the 3.0
Mm-1 threshold for visibility impacts in MANE-VU's
analysis,\107\ Maryland concluded that it had met the requirements for
Ask 2.
---------------------------------------------------------------------------

    \101\ H.A. Wagner Unit 3.
    \102\ Luke Paper Unit 001-0011-3-0018 & Unit 001-0011-3-0019.
    \103\ Raven Power Fort Smallwood, LLC.
    \104\ See Appendix 19, ``Herbert A. Wagner Generating Station
Consent Order''.
    \105\ See Section 2.5.2 of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).
    \106\ See docket documents, ``Verso Luke Paper--Luke MD Title V
Permit Termination (May 7, 2020)'' and ``Verso Luke Paper--Verso
Luke Close Out Letter (May 8, 2020)''.
    \107\ See Appendix 4, ``2016 MANE VU Source Contribution
Modeling Report: CALPUFF Modeling of Large Electrical Generating
Units and Industrial Sources (April 4, 2017)''.
---------------------------------------------------------------------------

    The EPA proposes to find that Maryland reasonably determined it has
satisfied Ask 2. As explained above, we

do not necessarily agree that a 3.0 Mm-1 threshold for
selecting sources for four-factor analysis results in a set of sources
the evaluation of which has the potential to meaningfully reduce the
state's contribution to visibility impairment. MANE-VU's threshold
identified only two sources in Maryland for four-factor analysis.
However, in this instance we propose to find that Maryland's additional
information and explanation indicates that the state has in fact
examined a reasonable set of sources; Maryland chose to address 12 of
the 13 sources identified by FLMs, including 10 that went beyond the
MANE-VU source selection process, and reasonably concluded that four-
factor analyses for its top-impacting sources are not necessary because
the outcome would be that no further emission reductions would be
reasonable. EPA is basing this proposed finding on the state's
examination of its largest operating EGU and ICI sources, at the time
of SIP submission, and on the emissions from and controls that apply to
those sources, as well as on Maryland's existing SIP-approved
NOX and SO2 rules that effectively control
emissions from the largest contributing stationary-source sectors.
Maryland's submittal includes additional information on and analysis of
13 Maryland facilities, which was provided in response a National Park
Service (NPS) analysis that identified these facilities as contributing
to ``80% of the Q/d total'' visibility impact at downwind NPS Class I
Federal areas based on 2014 emissions data and requested that states
``review and consider these sources for inclusion in their long term
strategies''.\108\ \109\ Maryland provided the NPS with additional
information on these 13 facilities, including facility descriptions,
current control devices/technologies for NOX,
SO2, and PM, current monitoring devices, regulations/consent
orders/permit conditions that limit emissions, and analysis and
documentation of historical emissions to demonstrate control strategy
effectiveness.
---------------------------------------------------------------------------

    \108\ See Section 2.6.1 and Table 2-12 of the MD Regional Haze
SIP for the Second Implementation Period 2018-2028 (February 8,
2022).
    \109\ See docket document, ``NPS Letter--MANE-VU draft Statement
on source screening (April 12, 2018)''.
---------------------------------------------------------------------------

    Maryland also examined the 13 facilities identified by NPS as a
percent of their total Q/d contribution. This included Luke Paper
Company, which comprised 54.71% of the Q/d total; Maryland stated that
this facility ceased operations, shut down and surrendered their
existing air permits as of May 7, 2020.\110\ When combined with Brandon
Shores Generating Station, H.A. Wagner Generating Station, Chalk Point
Generating Station, C.P. Crane Generating Station, and Naval Support
Facility Indian Head, all of which have closed, will close by 2026, or
have switched or will switch fuels, and Morgantown Generating Station,
which is considered by Maryland as effectively controlled through SCR,
these facilities comprised 75.57% of the Q/d total. When adding the two
municipal solid waste combustor facilities identified by the NPS
(Wheelabrator and Montgomery County RRF) both of which are considered
by Maryland as well-controlled, these facilities comprise 82.22% of the
Q/d total. Finally, Maryland also provided additional information on
the remaining three sources identified by the NPS (Holcim Cement,
Lehigh Cement, and the AES Warrior Run EGU).\111\ Therefore, EPA finds
it reasonable to conclude that Maryland has satisfied Ask 2.
---------------------------------------------------------------------------

    \110\ See docket documents, ``Verso Luke Paper--Luke MD Title V
Permit Termination (May 7, 2020)'' and ``Verso Luke Paper--Verso
Luke Close Out Letter (May 8, 2020)''.
    \111\ See Section 2.6.1 and Table 2-13 of the MD Regional Haze
SIP for the Second Implementation Period 2018-2028 (February 8,
2022).
---------------------------------------------------------------------------

    Ask 3, which addresses the sulfur content of heating oil used in
MANE-VU states, is based on a four-factor analysis for the heating oil
sulfur reduction regulations contained in that Ask; \112\ specifically,
for the control strategy of reducing the sulfur content of distillate
oil to 15 ppm. The analysis started with an assessment of the costs of
retrofitting refineries to produce 15 ppm heating oil in sufficient
quantities to support implementation of the standard, as well as the
impacts of requiring a reduction in sulfur content on consumer prices.
The analysis noted that, as a result of previous EPA rulemakings to
reduce the sulfur content of on-road and non-road-fuels to 15 ppm,
technologies are currently available to achieve sulfur reductions and
many refiners are already meeting this standard, meaning that the
capital investments for further reductions in the sulfur content of
heating oil are expected to be relatively low compared to costs
incurred in the past. The analysis also examined, by way of example,
the impacts of New York's existing 15 ppm sulfur requirements on
heating oil prices and concluded that the cost associated with reducing
sulfur was relatively small in terms of the absolute price of heating
oil compared to the magnitude of volatility in crude oil prices. It
also noted that the slight price premium is compensated by cost savings
due to the benefits of lower-sulfur fuels in terms of equipment life
and maintenance and fuel stability. Consideration of the time necessary
for compliance with a 15 ppm sulfur standard was accomplished through a
discussion of the amount of time refiners had needed to comply with the
EPA's on-road and non-road fuel 15 ppm requirement, and the
implications existing refinery capacity and distribution infrastructure
may have for compliance times with a 15 ppm heating oil standard. The
analysis concluded that with phased-in timing for states that have not
yet adopted a 15 ppm heating oil standard there ``appears to be
sufficient time to allow refiners to add any additional heating oil
capacity that may be required.'' \113\ The analysis further noted the
beneficial energy and non-air quality environmental impacts of a 15 ppm
sulfur heating oil requirement and that reducing sulfur content may
also have a salutary impact on the remaining useful life of residential
furnaces and boilers.\114\
---------------------------------------------------------------------------

    \112\ See docket document, ``2016 Updates to the Assessment of
Reasonable Progress for Regional Haze in MANE-VU Class I Areas
(January 31, 2016)'' at 8-4.
    \113\ Id. see 8-7.
    \114\ Id. see 8-8.
---------------------------------------------------------------------------

    EPA proposes to find that Maryland reasonably relied on MANE-VU's
four-factor analysis for a low-sulfur fuel oil regulation, which
engaged with each of the statutory factors and explained how the
information supported a conclusion that a 15 ppm sulfur fuel oil
standard is reasonable; as a reminder, MANE-VU Ask 3 requests that, for
``each MANE-VU state that has not yet fully adopted an ultra-low fuel
oil standard as requested by MANE-VU in 2007'', to ``pursue this
standard as expeditiously as possible and before 2028, depending on
supply availability''. Maryland's ultra-low sulfur fuel oil regulations
\115\ are consistent with Ask 3. EPA therefore proposes to find that
Maryland reasonably determined that it has satisfied Ask 3.
---------------------------------------------------------------------------

    \115\ See COMAR <IP_ADDRESS>, ``Specifications for No. 1 and No.
2 Fuel Oil (ASTM D-396)''.
---------------------------------------------------------------------------

    Maryland concluded that no additional updates were needed to meet
Ask 4, which requests that MANE-VU states pursue updating permits,
enforceable agreements, and/or rules to lock-in lower emission rates
for sources larger than 250 MMBtu per hour that have switched to lower
emitting fuels. As explained above, Maryland has asserted that EGUs and
other large point emission sources that have switched operations to
lower emitting fuels are already locked into the lower emission rates
for NOX, SO2, and PM by permits,

enforceable agreements and/or rules. In addition, modified units in
Maryland are required to amend their permits through the New Source
Review (NSR) process if they plan to switch back to coal or a fuel that
will increase emissions. A change in fuel, unless already allowed in
the permit, would be a modification,\116\ and Maryland's regulations
require that an application to modify the permit be submitted prior to
a change in fuel.\117\ As a reminder, MANE-VU Ask 4 requests that
states ``pursue updating permits, enforceable agreements, and/or rules
to lock-in lower emission rates for SO2, NOX, and
PM'' at ``EGUs and other large point emission sources larger than 250
MMBTU per hour heat input that have switched to lower emitting fuels''.
Ask 4 also states that ``the permit, enforceable agreement, and/or rule
can allow for suspension of the lower emission rate during natural gas
curtailment''. EPA proposes to find that Maryland reasonably determined
it has satisfied Ask 4. This is because the permitting and regulatory
requirements outlined above, including the fact that sources that have
switched fuel are generally required to revise their permits to reflect
the change, and because the state rules make any proposed reversion
difficult by requiring permitting and other control analyses, including
NSR.
---------------------------------------------------------------------------

    \116\ See COMAR <IP_ADDRESS>, defining ``Modify'' or
``Modification'' to mean ``any physical change in, or change in the
operation of, a source or installation which causes a change in the
quantity, nature or characteristics of emissions from the source or
installation. However, this term excludes routine maintenance and
routine repair, and increases in the hours of operation or in the
production rate, unless these increases would be prohibited under
any permit or approval conditions adopted by the Department.''
    \117\ See COMAR <IP_ADDRESS>., ``General Provisions'', which
states that ``A permit to construct and an approval from the
Department is required before construction or modification of a
source''.
---------------------------------------------------------------------------

    Ask 5 addresses NOX emissions from peaking combustion
turbines \118\ that have the potential to operate on high electric
demand days (HEDD).\119\ Maryland conducted a four-factor analysis to
evaluate potential control options for HEDD units. For one potentially
technically feasible control option, Selective Catalytic Reduction
(SCR), Maryland estimated compliance costs as ranging from $6 million
to $15.7 million per unit.\120\ These cost estimates are similar to
those found in EPA's Combustion Turbine NOX Control
Technology Memo published in January 2022.\121\ Due to the relatively
low level of reported annual NOX emissions from these units
within the state (i.e., less than 10 tons of NOX emitted per
unit per year), Maryland concluded that SCR was not an economically
feasible control option due to the high cost of control. Maryland also
evaluated the cost of water/steam injection as a potentially
technically feasible control option, but found that the cost of control
($87,906.95 per ton of NOX removed) was not economically
feasible.\122\ As a reminder, MANE-VU Ask 5 requests that MANE-VU
states, ``where emission rules have not been adopted, control
NOX emissions for peaking combustion turbines that have the
potential to operate on high electric demand days'' by either: ``(a)
Striving to meet NOX emissions standards of no greater than
22 ppm at 15% O2 for natural gas and 42 ppm at 15%
O2 for fuel oil but at a minimum meet NOX
emission standards of no greater than 42 ppm at 15% O2 for
natural gas and 96 ppm at 15% O2 for fuel oil'', or ``(b)
Performing a four-factor analysis for reasonable installation of or
upgrade to emission controls'', or ``(c) Obtaining equivalent emission
reductions on high electric demand days.'' \123\ Because Maryland
evaluated multiple technically feasible controls, the high cost of
controls, and the relatively low level of reported annual
NOX emissions from peaking combustion turbines with the
potential to operate on HEDD days, EPA proposes to find that Maryland
reasonably concluded that it has satisfied Ask 5.
---------------------------------------------------------------------------

    \118\ Peaking combustion turbine is defined for the purpose of
this Ask as a turbine capable of generating 15 megawatts or more,
that commenced operation prior to May 1, 2007, is used to generate
electricity all or part of which is delivered to electric power
distribution grid for commercial sale and that operated less than or
equal to an average of 1,752 hours (or 20%) per year during 2014 to
2016.
    \119\ High electric demand days are days when higher than usual
electrical demands bring additional generation units online, many of
which are infrequently operated and may have significantly higher
emissions rates of the generation fleet.
    \120\ See Section 2.5.5 of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).
    \121\ See docket document, ``EPA Combustion Turbine
NOX Control Technology Memo (January 2022)''.
    \122\ See Section 2.5.5 of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).
    \123\ See Appendix 7, ``MANE-VU Regional Haze Consultation
Report (July 27, 2018),'' of the MD Regional Haze SIP for the Second
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    Finally, regarding Ask 6, Maryland explains the greenhouse gas
initiatives and clean energy requirements within the state, including
promulgation of the state's 2030 Greenhouse Gas Reduction Act (GGRA)
Plan, RPS, and participation in RGGI. As a reminder, MANE-VU Ask 6, the
last Ask, requests that ``each State should consider and report in
their SIP measures or programs to: (a) decrease energy demand through
the use of energy efficiency, and (b) increase the use within their
state of Combined Heat and Power (CHP) and other clean Distributed
Generation technologies including fuel cells, wind, and solar''.\124\
The EPA is therefore proposing to find that Maryland has satisfied Ask
6's request to consider and report in its SIP measures or programs
related to energy efficiency, cogeneration, and other clean distributed
generation technologies.
---------------------------------------------------------------------------

    \124\ See Appendix 7, ``MANE-VU Regional Haze Consultation
Report (July 27, 2018),'' of the MD Regional Haze SIP for the Second
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    In sum, the EPA is proposing to find that--based on Maryland's
participation in the MANE-VU planning process, how it has addressed
each of the Asks, its supplemental information and explanation
regarding NOX sources and emissions, and the EPA's
additional assessment of Maryland's emissions and point sources--
Maryland has complied with the requirements of 40 CFR 51.308(f)(2)(i).
Specifically, MANE-VU Asks 2 and 3 engage with the requirement that
states evaluate and determine the emission reduction measures that are
necessary to make reasonable progress by considering the four statutory
factors. EPA is proposing to find Maryland's approach to Ask 2
reasonable because it demonstrated that the sources with the greatest
modeled impacts on visibility either have federally-enforceable shut
downs, have reduced their emissions so significantly that it is clear a
four-factor analysis would not yield further reasonable emission
reductions, or are subject to stringent emission control measures.
Maryland's SIP-approved control measures, emissions inventory \125\ and
information provided in response to comments \126\ demonstrate that the
sources of SO2 and NOX within the state that
would be expected to contribute to visibility impairment have small
emissions of NOX and SO2, are well controlled, or
both. Maryland's sulfur in fuel limits sets stringent limits for sulfur
content and SO2 emissions for non-solid fuels.\127\
Therefore, it is reasonable to assume that selecting additional sources
from MANE-VU's or FLMs' lists for four-factor analysis would not have
resulted in additional emission

reduction measures being determined to be necessary to make reasonable
progress for the second implementation period.
---------------------------------------------------------------------------

    \125\ See Appendix 1, ``Selection of States for MANE-VU Regional
Haze Consultation (2018)--Final''.
    \126\ See Appendix 20, ``Public Hearing Notices, Comments, and
Responses--Regional Haze Second Implementation Period Plan (2018-
2028)''.
    \127\ See COMAR <IP_ADDRESS>, ``Specifications for No. 1 and No.
2 Fuel Oil (ASTM D-396)''.
---------------------------------------------------------------------------

    Additionally, MANE-VU conducted a four-factor analysis to support
Ask 3, which requests that states pursue ultra-low sulfur fuel oil
standards to address SO2 emissions. Maryland has done so.
This also contributes to satisfying the requirements that states
determine the emission reduction measures that are necessary to make
reasonable progress by considering the four factors, and that their
long-term strategies include the enforceable emission limitations,
compliance schedules, and other measures necessary to make reasonable
progress. To the extent that MANE-VU and Maryland regard the measures
in Asks 1 and 4 through 6 as being part of the region's strategy for
making reasonable progress, we propose to find it reasonable for
Maryland to address these Asks by pointing to existing measures that
satisfy each.
3. Additional Long-Term Strategy Requirements
    The consultation requirements of 40 CFR 51.308(f)(2)(ii) provides
that states must consult with other states that are reasonably
anticipated to contribute to visibility impairment in a Class I area to
develop coordinate emission management strategies containing the
emission reductions measures that are necessary to make reasonable
progress. Section 51.308(f)(2)(ii)(A) and (B) require states to
consider the emission reduction measures identified by other states as
necessary for reasonable progress and to include agreed upon measures
in their SIPs, respectively. Section 51.308(f)(2)(ii)(C) speaks to what
happens if states cannot agree on what measures are necessary to make
reasonable progress.
    Maryland participated in and provided documentation of the MANE-VU
intra- and inter-RPO consultation processes and addressed the MANE-VU
Asks by providing information on the measures it has in place that
satisfy each Ask.128 129 MANE-VU also documented
disagreements that occurred during consultation. MANE-VU noted in their
Consultation Report that upwind states expressed concern regarding the
analyses the RPO utilized for the selection of states for the
consultation. MANE-VU agreed that these tools, as all models, have
their limitations, but nonetheless deemed them appropriate.
Additionally, there were several comments regarding the choice of the
2011 modeling base year. MANE-VU agreed that the choice of base year is
critical to the outcome of the study. MANE-VU acknowledged that there
were newer versions of the emission inventories and the need to use the
best available inventory for each analysis. However, MANE-VU disagreed
that the choice of these inventories was not appropriate for the
analysis. Upwind states also suggested that MANE-VU states adopt the
2021 timeline for regional haze SIP submissions for the second planning
period. MANE-VU agreed with the reasons the comments provided, such as
collaboration with data and planning efforts. However, MANE-VU
disagreed that the 2018 timeline would prohibit collaboration.
Additionally, upwind states noted that they would not be able to
address the MANE-VU Asks until they finalize their SIPs. MANE-VU
believed the assumption of the implementation of the Asks from upwind
states in its 2028 control case modeling was reasonable.
---------------------------------------------------------------------------

    \128\ See Appendix 5, ``Inter-RPO Consultation Briefing Book'';
Appendix 7, ``MANE-VU Regional Haze Consultation Report''; Appendix
9, ``National Park Service Letter to MANE-VU (April 2018)''; and
Appendix 17, ``Additional MANE-VU documentation for establishing 3.0
Mm-1 Threshold''.
    \129\ See Appendix 14, ``FLM Consultation Initiation Letter
(April 2019)''; Appendix 15, ``National Park Service Correspondence
with Maryland''; Appendix 16, ``US Forest Service Consultation
Response Letter''; and Appendix 20, ``Public Hearing Notices,
Comments, and Responses--Regional Haze Second Implementation Period
Plan (2018-2028)''.
---------------------------------------------------------------------------

    In sum, Maryland participated in the MANE-VU intra- and inter-RPO
consultation and satisfied the MANE-VU Asks, satisfying 40 CFR
51.308(f)(2)(ii)(A) and (B). Maryland satisfied 40 CFR
51.308(f)(2)(ii)(C) by participating in MANE-VU's consultation process,
which documented the disagreements between the upwind states and MANE-
VU and explained MANE-VU's reasoning on each of the disputed issues.
Based on the entirety of MANE-VU's intra- and inter-RPO consultation
and both MANE-VU's and Maryland's responses to states' comments on the
SIP submission and various technical analyses therein, we propose to
determine that Maryland has satisfied the consultation requirements of
40 CFR 51.308(f)(2)(ii).
    The documentation requirement of 40 CFR 51.308(f)(2)(iii) provides
that states may meet their obligations to document the technical bases
on which they are relying to determine the emission reductions measures
that are necessary to make reasonable progress through an RPO, as long
as the process has been ``approved by all State participants.'' As
explained above, Maryland chose to rely on MANE-VU's technical
information, modeling, and analysis to support development of its long-
term strategy. The MANE-VU technical analyses on which Maryland relied
are listed in the state's SIP submission and include source
contribution assessments, information on each of the four factors and
visibility modeling information for certain EGUs, and evaluations of
emission reduction strategies for specific source categories. Maryland
also provided supplemental information to further demonstrate the
technical bases and emission information on which it relied on to
determine the emission reductions measures that are necessary to make
reasonable progress. Based on the documentation provided by the state,
we propose to find Maryland satisfies the documentation requirements of
40 CFR 51.308(f)(2)(iii).
    Section 51.308(f)(2)(iii) also requires that the emissions
information considered to determine the measures that are necessary to
make reasonable progress include information on emissions for the most
recent year for which the state has submitted triennial emissions data
to the EPA (or a more recent year), with a 12-month exemption period
for newly submitted data. Maryland's SIP submission included 2017 NEI
emission data for NOX, SO2, PM, and
NH3 and 2017 Air Markets Program Data (AMPD) emissions for
NOX and SO2. Maryland's SIP submission also
included 2019 AMPD for NOX and SO2.\130\ Based on
Maryland's consideration and analysis of the 2017 and 2019 emission
data in their SIP submittal and supplemental documentation, the EPA
proposes to find that Maryland has satisfied the emissions information
requirement in 40 CFR 51.308(f)(2)(iii).
---------------------------------------------------------------------------

    \130\ See Section 2.21 of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    We also propose to find that Maryland reasonably considered the
five additional factors in 40 CFR 51.308(f)(2)(iv) in developing its
long-term strategy. Pursuant to 40 CFR 51.308(f)(2)(iv)(A), Maryland
noted that existing and ongoing state and Federal emission control
programs that contribute to emission reductions through 2028 would
impact emissions of visibility impairing pollutants from point and
nonpoint sources in the second implementation period. Maryland included
in their SIP comprehensive lists of control measures with their
effective dates, pollutants addressed, and corresponding Code of
Maryland Regulations provisions.\131\
---------------------------------------------------------------------------

    \131\ See Section 2.8.1 of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).

---------------------------------------------------------------------------

    Maryland's consideration of measures to mitigate the impacts of
construction activities as required by 40 CFR 51.308(f)(2)(iv)(B)
includes, in section 2.8.2 of its SIP submission, a list of measures
that Maryland has implemented to mitigate the impacts from such
activities. Maryland has implemented standards that reduce fugitive
dust emissions from construction,\132\ rules to address exhaust
emissions,133 134 135 including rules to limit the idling of
vehicles and equipment and rules to reduce allowable smoke from on-road
diesel engines,\136\ and general conformity rules.137 138
---------------------------------------------------------------------------

    \132\ COMAR <IP_ADDRESS>. ``Particulate Matter'', subsection D;
State Effective Date November 11, 2002 (29:22 Md. R. 1724) (68 FR
46487).
    \133\ COMAR 11.14. ``MOTOR VEHICLE ADMINISTRATION--VEHICLE
INSPECTIONS'', .01, .06, and .08.
    \134\ COMAR. 11.21.02. ``Diesel Vehicle Emissions Control
Program''; State Effective Date July 10, 2000 (27:13 Md. R. 1212).
    \135\ Md. Code, Transp. Sec.  23-401 through 23-404.
    \136\ Md. Code, Transp. Sec.  21-1101.
    \137\ The authority to address General Conformity is set forth
in Section 176(c) of the Clean Air Act and the requirements to
demonstrate conformity are found in the EPA's implementing
regulation (40 CFR part 93, subpart B--Determining Conformity of
General Federal Actions to State or Federal Implementation Plans).
    \138\ COMAR 26.11.26. ``Conformity''; State Effective Date June
5, 1995 (22:11 Md. R. 825).
---------------------------------------------------------------------------

    Pursuant to 40 CFR 51.308(f)(2)(iv)(C), source retirements and
replacement schedules are addressed in section 2.8.3 of Maryland's
submission. Source retirements and replacements were considered in
developing the 2028 emission projections, with on the books/on the way
retirements and replacements included in the 2028 projections. The EGU
point sources included in the inventories used in the MANE-VU
contribution assessment and that were subsequently retired are
identified in Table 2-14.\139\ No non-EGU point source retirements in
Maryland were considered when developing the 2028 emissions
projections.
---------------------------------------------------------------------------

    \139\ See ``Table 2-14: Units Retired in the Regional Haze
Inventories'' of the MD Regional Haze SIP for the Second
Implementation Period 2018--2028 (February 8, 2022).
---------------------------------------------------------------------------

    In considering smoke management as required in 40 CFR
51.308(f)(2)(iv)(D), Maryland explained, in section 2.8.4 of its
submission, that emissions from agricultural and prescribed burning for
forestry smoke management within the state are low; PM2.5
statewide emissions from prescribed fires were 1,349.18 tons (4.13% of
Maryland's overall PM2.5 emissions inventory) and emissions
from agricultural burning were 1.5 tons (<1% of Maryland's overall
PM2.5 emissions inventory). Maryland therefore concludes
that it is unlikely that fires in Maryland for agricultural or forestry
management cause impacts on visibility in the MANE-VU and nearby Class
I areas, including Shenandoah, Dolly Sods, Otter Creek, and James River
Face. Maryland states that Smoke Management Plans is a required element
of a SIP only if it is required to make reasonable progress, and that
although Maryland does not need an official Smoke Management Plan, it
has the legal authority to manage burning through a formal permitting
system if necessary.
    Maryland considered the anticipated net effect of projected changes
in emissions as required by 40 CFR 51.308(f)(2)(iv)(E) by discussing,
in section 2.8.5 of its submission, the photochemical modeling for the
2018-2028 period it conducted in collaboration with MANE-VU. The two
modeling cases run were a 2028 base case, which considered only on-the-
books controls, and a 2028 control case that considered implementation
of the MANE-VU Ask. Maryland presented the differences between the base
and control cases on the 20% most impaired and 20% clearest days for
each MANE-VU Class I area.\140\
---------------------------------------------------------------------------

    \140\ See Figures 2-7 through 2-10 of the MD Regional Haze SIP
for the Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    Because Maryland has reasonably considered each of the five
additional factors the EPA proposes to find that Maryland has satisfied
the requirements of 40 CFR 51.308(f)(2)(iv).

F. Reasonable Progress Goals

    Section 51.308(f)(3) contains the requirements pertaining to RPGs
for each Class I area. Section 51.308(f)(3)(i) requires a state in
which a Class I area is located to establish RPGs--one each for the
most impaired and clearest days--reflecting the visibility conditions
that will be achieved at the end of the implementation period as a
result of the emission limitations, compliance schedules and other
measures required under paragraph (f)(2) to be in states' long-term
strategies, as well as implementation of other CAA requirements. The
long-term strategies as reflected by the RPGs must provide for an
improvement in visibility on the most impaired days relative to the
baseline period and ensure no degradation on the clearest days relative
to the baseline period. Section 51.308(f)(3)(ii) applies in
circumstances in which a Class I area's RPG for the most impaired days
represents a slower rate of visibility improvement than the uniform
rate of progress calculated under 40 CFR 51.308(f)(1)(vi). Under 40 CFR
51.308(f)(3)(ii)(A), if the state in which a mandatory Class I area is
located establishes an RPG for the most impaired days that provides for
a slower rate of visibility improvement than the URP, the state must
demonstrate that there are no additional emission reduction measures
for anthropogenic sources or groups of sources in the state that would
be reasonable to include in its long-term strategy. Section
51.308(f)(3)(ii)(B) requires that if a state contains sources that are
reasonably anticipated to contribute to visibility impairment in a
Class I area in another state, and the RPG for the most impaired days
in that Class I area is above the URP, the upwind state must provide
the same demonstration. Because Maryland has no Class I areas within
its borders, it is subject only to 40 CFR 51.308(f)(3)(ii)(B).
    Under 40 CFR 51.308(f)(3)(ii)(B), a state that contains sources
that are reasonably anticipated to contribute to visibility impairment
in a Class I area in another state for which a demonstration by the
other state is required under 40 CFR 51.308(f)(3)(ii)(B) must
demonstrate that there are no additional emission reduction measures
that would be reasonable to include in its long-term strategy.
Maryland's SIP submittal included MANE-VU's glidepath checks for nearby
downwind Class I areas,141 142 which show that the RPG for
the 20 percent most anthropogenically impaired days for the affected
downwind Class I areas (Acadia, Brigantine, Great Gulf, Lye Brook,
Moosehorn, Dolly Sods and Shenandoah) are not above the URP glidepath,
and that the RPG for the 20 percent clearest days shows no degradation.
In addition, the modeled MANE-VU 2028 visibility projections at nearby
Class I areas \143\ show that the base case 2028 projections for the
most impaired days at these areas are below the respective 2028 points
on the URPs. Therefore, we propose it is reasonable to assume that the
demonstration requirement under 40 CFR 51.308(f)(3)(ii)(B) as it
pertains to these areas will not be triggered.
---------------------------------------------------------------------------

    \141\ See docket document, ``TD MANE-VU 2000-19 RH METRICS
COMPARISON PLOTS 12-19-20.xlsx''.
    \142\ See docket document, ``TD MANE-VU 2000-19 RHII & III
Metrics Trends Plots 12-19-20.xlsx''.
    \143\ See docket document, ``MANE-VU Trends 2004-17 Report 2nd
SIP Metrics--December 2018 Update--Final''.
---------------------------------------------------------------------------

    The EPA proposes to determine that Maryland has satisfied the
applicable requirements of 40 CFR 51.308(f)(3) relating to RPGs.

G. Monitoring Strategy and Other Implementation Plan Requirements

    Section 51.308(f)(6) specifies that each comprehensive revision of
a state's regional haze SIP must contain or provide for certain
elements, including monitoring strategies, emissions inventories, and
any reporting, recordkeeping and other measures needed to assess and
report on visibility. A main requirement of this subsection is for
states with Class I areas to submit monitoring strategies for
measuring, characterizing, and reporting on visibility impairment.
Compliance with this requirement may be met through participation in
the Interagency Monitoring of Protected Visual Environments (IMPROVE)
network.
    Section 51.308(f)(6)(i) requires SIPs to provide for the
establishment of any additional monitoring sites or equipment needed to
assess whether reasonable progress goals to address regional haze for
all mandatory Class I Federal areas within the state are being
achieved. Section 51.308(f)(6)(ii) requires SIPs to provide for
procedures by which monitoring data and other information are used in
determining the contribution of emissions from within the state to
regional haze visibility impairment at mandatory Class I Federal areas
both within and outside the state. Because Maryland does not have any
Class I Federal areas located within its borders, Section
51.308(f)(6)(i) and (ii) do not apply.
    Section 51.308(f)(6)(iii) requires states with no Class I areas to
include procedures by which monitoring data and other information are
used in determining the contribution of emissions from within the State
to regional haze visibility impairment at Class I areas in other
states. States with Class I areas must establish a monitoring program
and report data to EPA that is representative of visibility at the
Class I Federal areas. The IMPROVE network meets this requirement.
Maryland stated that, as a participant in MANE-VU, it reviewed
information about the chemical composition of baseline monitoring data
at Class I Federal areas in and near MANE-VU in order to understand the
sources of haze causing pollutants. Maryland commits to continuing
support of ongoing visibility monitoring in Class I Federal areas,
agrees that the IMPROVE network is an appropriate monitoring network to
track regional haze progress, and commits to working with neighboring
states and FLMs to meet the goals of the IMPROVE program. Maryland also
commits to using monitoring data and procedures consistent with US EPA
guidance to review progress and trends in visibility at Class I Federal
areas that may be affected by emissions from Maryland, both for
comprehensive periodic revisions of this implementation plan and for
periodic reports describing progress towards the reasonable progress
goals for those areas.\144\
---------------------------------------------------------------------------

    \144\ See Section 2.16 of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    Section 51.308(f)(6)(iv) requires the SIP to provide for the
reporting of all visibility monitoring data to the Administrator at
least annually for each Class I area in the state. As noted above,
Maryland does not have any Class I Federal areas located within its
borders, therefore this requirement does not apply.
    Section 51.308(f)(6)(v) requires SIPs to provide for a statewide
inventory of emissions of pollutants that are reasonably anticipated to
cause or contribute to visibility impairment, including emissions for
the most recent year for which data are available and estimates of
future projected emissions. It also requires a commitment to update the
inventory periodically. Maryland provides for emissions inventories and
estimates for future projected emissions by participating in the MANE-
VU RPO and complying with EPA's Air Emissions Reporting Rule (AERR). In
40 CFR part 51, subpart A, the AERR requires states to submit updated
emissions inventories for criteria pollutants to EPA's Emissions
Inventory System (EIS) every three years. The emission inventory data
is used to develop the NEI, which provides for, among other things, a
triennial state-wide inventory of pollutants that are reasonably
anticipated to cause or contribute to visibility impairment.
    Section 2.21 of Maryland's submission includes tables of NEI data.
The source categories of the emissions inventories included are: (1)
point sources, (2) nonpoint sources, (3) non-road mobile sources, and
(4) on-road mobile sources. The point source category is further
divided into AMPD point sources and non-AMPD point sources.\145\
Maryland included NEI emissions inventories for the following years:
2002 (one of the regional haze program baseline years), 2008, 2011,
2014, and 2017; and for the following pollutants: SO2,
NOX, PM10, PM2.5, VOCs, and
NH3. Maryland also provided a summary of SO2 and
NOX emissions for AMPD sources for the years of 2016, 2017,
2018, and 2019.
---------------------------------------------------------------------------

    \145\ AMPD sources are facilities that participate in EPA's
emission trading programs. The majority of AMPD sources are electric
generating units (EGUs).
---------------------------------------------------------------------------

    Section 51.308(f)(6)(v) also requires states to include estimates
of future projected emissions and include a commitment to update the
inventory periodically. Maryland relied on the MANE-VU 2028 emissions
projections for MANE-VU states. MANE-VU completed two 2028 projected
emissions modeling cases--a 2028 base case that considers only on-the-
books controls and a 2028 control case that considers implementation of
the MANE-VU Asks.\146\
---------------------------------------------------------------------------

    \146\ See Appendix 11 ``Ozone Transport Commission/Mid-Atlantic
Northeastern Visibility Union 2011 Based Modeling Platform Support
Document--October 2018 Update (October 2018)''.
---------------------------------------------------------------------------

    EPA proposes to find that Maryland has met the requirements of 40
CFR 51.308(f)(6) as described above, including through its continued
participation in the IMPROVE network and the MANE-VU RPO and its on-
going compliance with the AERR, and that no further elements are
necessary at this time for Maryland to assess and report on visibility
pursuant to 40 CFR 51.308(f)(6)(vi).

H. Requirements for Periodic Reports Describing Progress Towards the
Reasonable Progress Goals

    Section 51.308(f)(5) requires that periodic comprehensive revisions
of states' regional haze plans also address the progress report
requirements of 40 CFR 51.308(g)(1) through (5). The purpose of these
requirements is to evaluate progress towards the applicable RPGs for
each Class I area within the state and each Class I area outside the
state that may be affected by emissions from within that state. Section
51.308(g)(1) and (2) apply to all states and require a description of
the status of implementation of all measures included in a state's
first implementation period regional haze plan and a summary of the
emission reductions achieved through implementation of those measures.
Section 51.308(g)(3) applies only to states with Class I areas within
their borders and requires such states to assess current visibility
conditions, changes in visibility relative to baseline (2000-2004)
visibility conditions, and changes in visibility conditions relative to
the period addressed in the first implementation period progress
report. Section 51.308(g)(4) applies to all states and requires an
analysis tracking changes in emissions of pollutants contributing to
visibility impairment from all sources and sectors since the period
addressed by the first implementation period progress report. This
provision further specifies the year

or years through which the analysis must extend depending on the type
of source and the platform through which its emission information is
reported. Finally, 40 CFR 51.308(g)(5), which also applies to all
states, requires an assessment of any significant changes in
anthropogenic emissions within or outside the state have occurred since
the period addressed by the first implementation period progress
report, including whether such changes were anticipated and whether
they have limited or impeded expected progress towards reducing
emissions and improving visibility.
    Maryland's submission describes the status of measures of the long-
term strategy from the first implementation period. As a member of
MANE-VU, Maryland considered the MANE-VU Asks and adopted corresponding
measures into its long-term strategy for the first implementation
period. The MANE-VU Asks were: (1) Timely implementation of Best
Available Retrofit Technology (BART) requirements; (2) EGU controls
including Controls at 167 Key Sources that most affect MANE-VU Class I
areas; (3) Low sulfur fuel oil strategy; and (4) Continued evaluation
of other control measures. Maryland met all the identified reasonable
measures requested during the first implementation period. During the
first planning period for regional haze, programs that were put in
place focused on reducing sulfur dioxide (SO2) emissions.
The reductions achieved led to vast improvements in visibility at the
MANE-VU Federal Class I Areas due to reduced sulfates formed from
SO2 emissions. Maryland describes in Section 2.18 of its
submittal control measures put in place during the first implementation
period to help reduce the emissions of visibility-impairing pollutants,
including NOX and SO2. This includes the Maryland
Healthy Air Act (HAA), which covered Maryland emission sources named in
MANE-VU's ``167 Stacks''; the HAA was implemented in 2010 and further
tightened SO2 emission control requirements in 2013,
resulting in significant reductions in visibility-impairing pollutants
throughout the state that exceeded MANE-VU target goals. Maryland also
described its implementation of low sulfur fuel oil standards for the
state, and the status of the remaining emissions sources in the state
subject to BART requirements, which included emission reductions for
Portland cement plants to satisfy Reasonably Available Control
Technology (RACT) requirements for ozone.\147\
---------------------------------------------------------------------------

    \147\ COMAR 26.11.30--Control of Portland Cement Manufacturing
Plants. Effective date: July 20, 2015 (42:Md. R. 884).
www.dsd.state.md.us/comar/SubtitleSearch.aspx?search=26.11.30.*
Approved by EPA March 28, 2018, 83 FR 13192
---------------------------------------------------------------------------

    EPA proposes to find that Maryland has met the requirements of 40
CFR 51.308(g)(1) and (2) because its SIP submission describes the
measures included in the long-term strategy from the first
implementation period, as well as the status of their implementation
and the emission reductions achieved through such implementation.
    Section 51.308(g)(3) requires states to assess Reasonable Progress
Goals, including current visibility conditions and changes, for any
Class I areas within the state. As described above, Maryland does not
have any Class I areas within its borders, therefore 40 CFR
51.308(g)(3) does not apply.
    Pursuant to 40 CFR 51.308(g)(4), in Section 2.21 of their
submittal, Maryland provided a summary of emissions of NOX,
SO2, PM10, PM2.5, VOCs, and
NH3 from all sources and activities, including from point,
nonpoint, non-road mobile, and on-road mobile sources, for the time
period from 2002 to 2017. Maryland also included AMPD data for
SO2 and NOX emissions for 2016, 2017, 2018, and
2019 in their submission.
    The reductions achieved through Maryland emission control measures
are seen in the emissions inventory. Based on Maryland's SIP submittal,
NOX emissions have continuously declined in Maryland from
2002 through 2017, especially in the point, nonroad and onroad mobile
sectors. During that period, onroad sources contributed almost half of
the emissions at 47%, followed by point sources at 27%. Nonroad sources
contributed 13% and area sources contributed 13%. Table 2-20 of
Maryland's SIP submittal also shows additional NOX emissions
data from 2016 to 2019 for Maryland's point sources that report to
EPA's AMPD. NOX emissions are expected to continue to
decrease as fleet turnover occurs and the older more polluting vehicles
and equipment are replaced by newer, cleaner ones.\148\
---------------------------------------------------------------------------

    \148\ See Section 2.21.1 and Table 2-20 of the MD Regional Haze
SIP for the Second Implementation Period 2018--2028 (February 8,
2022)
---------------------------------------------------------------------------

    Emissions of SO2 have shown a significant decline in
Maryland from 2002 to 2017 across multiple sectors; see Section 2.21.3
and Table 2-28 of Maryland's SIP submittal.\149\ Reductions in point
emissions are primarily due to the acid rain program, Maryland power
plant consent decrees and regulations including the Maryland Health Air
Act, and Federal and State low sulfur fuel regulations. Additionally,
some of these decreases may be attributable to the MANE-VU low sulfur
fuel strategy and the 90% or greater reduction in SO2
emissions at 167 EGU stacks, both inside and outside of MANE-VU,
requested in the ``Non-MANE-VU Ask'' for states within MANE-VU for the
first regional haze planning period.\150\
---------------------------------------------------------------------------

    \149\ See Section 2.21.3 and Table 2-28 of the MD Regional Haze
SIP for the Second Implementation Period 2018-2028 (February 8,
2022).
    \150\ See ``Statement of the Mid-Atlantic/Northeast Visibility
Union (MANE-VU) Concerning a Course of Action within MANE-VU Toward
Assuring Reasonable Progress'' in the docket.
---------------------------------------------------------------------------

    Emissions of PM10 have steadily decreased in Maryland
from 2002 to 2017, particularly in the point and nonroad sectors; see
Section 2.21.2 and Table 2-25 of Maryland's SIP submittal.\151\ The
variations in the onroad sector are likely due to changes in emission
inventory calculation methodologies, which resulted in higher
particulate matter estimates in the other years than in 2002. The large
variation in emissions in the nonpoint category is likely due to
changes in calculation methodologies for residential wood burning and
fugitive dust categories, which have varied significantly.
---------------------------------------------------------------------------

    \151\ See Section 2.21.2 and Table 2-25 of the MD Regional Haze
SIP for the Second Implementation Period 2018-2028 (February 8,
2022).
---------------------------------------------------------------------------

    Emissions of ammonia (NH3) have shown declines in
Maryland from 2002 to 2017; see Section 2.21.4 and Table 2-33 of
Maryland's SIP submittal.\152\ Ammonia decreases were achieved in the
onroad sector due to Federal new engine standards for vehicles and
equipment. Nonpoint increases and decreases from 2002 to 2014 are due
to reporting, grouping and methodology changes. While ammonia emissions
grew slightly between the 2002 and 2008 emission inventories, ammonia
emissions have decreased from 2011 to 2017.
---------------------------------------------------------------------------

    \152\ See Section 2.21.4 and Table 2-33 of the MD Regional Haze
SIP for the Second Implementation Period 2018-2028 (February 8,
2022).
---------------------------------------------------------------------------

    The EPA is proposing to find that Maryland has satisfied the
requirements of 40 CFR 51.308(g)(4) by providing emissions information
for NOX, SO2, PM10, PM2.5,
VOCs, and NH3 broken down by type of source.
    Maryland uses the emissions trend data in the SIP submission \153\
and supporting MANE-VU information \154\ provided to support the
assessment that

anthropogenic haze-causing pollutant emissions in Maryland have
decreased during the reporting period and that changes in emissions
have not limited or impeded progress in reducing pollutant emissions
and improving visibility, Maryland 2017 emission inventories for
NOX, SO2, PM10, PM2.5,
VOCs, and NH3 were lower than their 2014 emission
inventories for those same pollutants emissions.\155\ The EPA is
proposing to find that Maryland has met the requirements of 40 CFR
51.308(g)(5).
---------------------------------------------------------------------------

    \153\ See Section 2.21 of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).
    \154\ See docket document, ``MANE-VU Trends 2004-17 Report 2nd
SIP Metrics - December 2018 Update--Final''.
    \155\ See Section 2.16 of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

I. Requirements for State and Federal Land Manager Coordination

    Section 169A(d) of the Clean Air Act requires states to consult
with FLMs before holding the public hearing on a proposed regional haze
SIP, and to include a summary of the FLMs' conclusions and
recommendations in the notice to the public. In addition, 40 CFR
51.308(i)(2)'s FLM consultation provision requires a state to provide
FLMs with an opportunity for consultation that is early enough in the
state's policy analyses of its emission reduction obligation so that
information and recommendations provided by the FLMs' can meaningfully
inform the state's decisions on its long-term strategy. If the
consultation has taken place at least 120 days before a public hearing
or public comment period, the opportunity for consultation will be
deemed early enough, Regardless, the opportunity for consultation must
be provided at least sixty days before a public hearing or public
comment period at the state level. Section 51.308(i)(2) also provides
two substantive topics on which FLMs must be provided an opportunity to
discuss with states: assessment of visibility impairment in any Class I
area and recommendations on the development and implementation of
strategies to address visibility impairment. Section 51.308(i)(3)
requires states, in developing their implementation plans, to include a
description of how they addressed FLMs' comments.
    The states in the MANE-VU RPO conducted FLM consultation early in
the planning process concurrent with the state-to-state consultation
that formed the basis of the RPO's decision making process. As part of
the consultation, the FLMs were given the opportunity to review and
comment on the technical documents developed by MANE-VU. The FLMs were
invited to attend the intra- and inter-RPO consultations calls among
states and at least one FLM representative was documented to have
attended seven intra-RPO meetings and all inter-RPO meetings. Maryland
participated in these consultation meetings and calls.\156\
---------------------------------------------------------------------------

    \156\ See Appendix 7, ``MANE-VU Regional Haze Consultation
Report (July 27, 2018),'' of the MD Regional Haze SIP for the Second
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    As part of this early engagement with the FLMs, on April 12, 2018,
the NPS sent letters to the MANE-VU states requesting that they
consider specific individual sources in their long-term
strategies.\157\ NPS used an analysis of emissions divided by distance
(Q/d) to estimate the impact of MANE-VU facilities. To select the
facilities, NPS first summed 2014 NEI NOX, PM10,
SO2, and SO4 emissions and divided by the
distance to a specified NPS mandatory Class I Federal area. NPS summed
the Q/d values across all MANE-VU states relative to Acadia, Mammoth
Cave and Shenandoah National Parks, ranked the Q/d values relative to
each Class I area, created a running total, and identified those
facilities contributing to 80% of the total impact at each NPS Class I
area. NPS applied a similar process to facilities in Maine relative to
Acadia National Park. NPS merged the resulting lists of facilities and
sorted them by their states. NPS suggested that a state consider those
facilities comprising 80% of the Q/d total, not to exceed the 25 top
ranked facilities. The NPS identified 12 facilities in Maryland in this
letter.\158\ Maryland included the NPS initial letter in their proposed
SIP. In a subsequent letter dated October 22, 2018, NPS identified 13
facilities for which more control information was desired.\159\
Maryland detailed the emission controls and updates to these facilities
in its SIP submittal to address the NPS's request for more
information.\160\
---------------------------------------------------------------------------

    \157\ See Appendix 7, ``MANE-VU Regional Haze Consultation
Report (July 27, 2018),'' and Appendix 9, ``National Park Service
Letter to MANE-VU (April 2018)'' of the MD Regional Haze SIP for the
Second Implementation Period 2018-2028 (February 8, 2022).
    \158\ See Appendix 7, ``MANE-VU Regional Haze Consultation
Report (July 27, 2018),'' of the MD Regional Haze SIP for the Second
Implementation Period 2018-2028 (February 8, 2022).
    \159\ See Appendix 15, ``National Park Service Correspondence
with Maryland'', of the MD Regional Haze SIP for the Second
Implementation Period 2018-2028 (February 8, 2022).
    \160\ See Section 2.6 and Appendix 20 of the MD Regional Haze
SIP for the Second Implementation Period 2018-2028 (February 8,
2022).
---------------------------------------------------------------------------

    On September 2, 2021, Maryland submitted a draft Regional Haze SIP
to the U.S. Forest Service, the U.S. Fish and Wildlife Service, and the
National Park Service for a 60-day review and comment period pursuant
to 40 CFR 51.308(i)(2).\161\ Maryland received comments from the Forest
Service on October 28, 2021, and from the National Park Service on
October 29, 2021. Maryland responded to the FLM comments and included
the responses in Appendix 20 of their submission to EPA, in accordance
with 40 CFR 51.308(i)(3). Notices of the proposed SIP, availability and
the public hearing were published on MDE's website and in the Maryland
Register, and interested parties were emailed the notice, along with
air quality contacts from other states, air quality regional
organizations and the EPA. A public hearing on the proposed SIP
revision was held on January 4, 2022. Written comments relevant to the
proposal were accepted until the close of business January 4, 2022.
---------------------------------------------------------------------------

    \161\ See Appendix 14, Appendix 15, Appendix 16, and Appendix 20
of the MD Regional Haze SIP for the Second Implementation Period
2018-2028 (February 8, 2022), and docket documents, ``National Park
Service Comments''; ``State of Maryland Mail--Forest Service'';
``USFS MD RH SIP Comment Letter''; ``USFS MD RH SIP Comment
Enclosure''
---------------------------------------------------------------------------

    For the reasons stated above, the EPA proposes to find that
Maryland has satisfied the requirements under 40 CFR 51.308(i) to
consult with the FLMs on its regional haze SIP for the second
implementation period.
    Maryland's February 8, 2022 SIP submission includes a commitment to
revise and submit a regional haze SIP by July 31, 2028, and every ten
years thereafter. The state's commitment includes submitting periodic
progress reports in accordance with 40 CFR 51.308(f) and a commitment
to evaluate progress towards the reasonable progress goal for each
mandatory Class I Federal area located within the state and in each
mandatory Class I Federal area located outside the state that may be
affected by emissions from within the state in accordance with 40 CFR
51.308(g).\162\
---------------------------------------------------------------------------

    \162\ See Section 2.17, ``Progress Report Requirements'', of the
MD Regional Haze SIP for the Second Implementation Period 2018-2028
(February 8, 2022).
---------------------------------------------------------------------------

V. Proposed Action

    EPA is proposing to approve Maryland's February 8, 2022 SIP
submission, as satisfying the regional haze requirements for the second
implementation period contained in 40 CFR 51.308(f).

VI. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP
submission

that complies with the provisions of the CAA and applicable Federal
regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP
submissions, EPA's role is to approve state choices, provided that they
meet the criteria of the CAA. Accordingly, this action merely proposes
to approve state law as meeting Federal requirements and does not
impose additional requirements beyond those imposed by state law. For
that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Orders
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21,
2011);
     Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA; and
    Executive Order 12898 (Federal Actions to Address Environmental
Justice in Minority Populations and Low-Income Populations, 59 FR 7629,
February 16, 1994) directs Federal agencies to identify and address
``disproportionately high and adverse human health or environmental
effects'' of their actions on minority populations and low-income
populations to the greatest extent practicable and permitted by law.
EPA defines environmental justice (EJ) as ``the fair treatment and
meaningful involvement of all people regardless of race, color,
national origin, or income with respect to the development,
implementation, and enforcement of environmental laws, regulations, and
policies.'' EPA further defines the term fair treatment to mean that
``no group of people should bear a disproportionate burden of
environmental harms and risks, including those resulting from the
negative environmental consequences of industrial, governmental, and
commercial operations or programs and policies.'' The Maryland
Department of the Environment did not evaluate environmental justice
considerations as part of its SIP submittal; the CAA and applicable
implementing regulations neither prohibit nor require such an
evaluation. EPA did not perform an EJ analysis and did not consider EJ
in this action. Due to the nature of the action being taken here, this
action is expected to have a neutral to positive impact on the air
quality of the affected area. Consideration of EJ is not required as
part of this action, and there is no information in the record
inconsistent with the stated goal of E.O. 12898 of achieving
environmental justice for people of color, low-income populations, and
Indigenous peoples.
    In addition, this proposed rulemaking action, pertaining to
Maryland regional haze SIP submission for the second planning period,
is not approved to apply on any Indian reservation land or in any other
area where the EPA or an Indian tribe has demonstrated that a tribe has
jurisdiction. In those areas of Indian country, the rule does not have
tribal implications and will not impose substantial direct costs on
tribal governments or preempt tribal law as specified by Executive
Order 13175 (65 FR 67249, November 9, 2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
Reference, Nitrogen dioxide, Ozone, Particulate matter, Sulfur oxides.

Adam Ortiz,
Regional Administrator, Region III.
[FR Doc. 2023-18278 Filed 8-24-23; 8:45 am]
BILLING CODE 6560-50-P


[Federal Register: May 19, 2010 (Volume 75, Number 96)]
[Proposed Rules]
[Page 27969-27972]
[DOCID:fr19my10-17]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0481; Directorate Identifier 2009-NM-192-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Model 737-100 and -
200 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to adopt a new airworthiness directive (AD) for
certain Model 737-100 and -200 series airplanes. This proposed AD would
require repetitive inspections for cracking and damaged fasteners of
certain fuselage frames and stub beams, and corrective actions if
necessary. For certain airplanes, this proposed AD would also require
repetitive inspections for cracking of the inboard chord fastener hole
of the frame at body station 639, stringer S-16, and corrective actions
if necessary. For certain airplanes, this proposed AD would also
require an inspection to determine the edge margin of the lower chord.
For airplanes with a certain short edge margin, this proposed AD
requires repetitive inspections for cracking, and corrective actions if
necessary; replacing the lower chord terminates the repetitive
inspections. This proposed AD requires an eventual preventive
modification. For certain airplanes, doing the modification or a repair
would terminate the repetitive inspections for the repaired or modified
frame only. For airplanes on which the modification or repair is done
at certain body stations, this proposed AD would require repetitive
inspections for cracking of certain frame webs and inner and outer
chords, and corrective actions if necessary. For certain other
airplanes, this proposed AD requires a modification which includes
reinforcing the body frame inner chords, replacing the stub beam upper
chords and attach angles, and reinforcing the stub beam web. This
proposed AD results from reports of fatigue cracks at certain frame
sections, in addition to stub beam cracking, caused by high flight
cycle stresses from both pressurization and maneuver load. We are
proposing this AD to detect and correct fatigue cracking of certain
fuselage frames and stub beams, and possible severed frames, which
could result in reduced structural integrity of the frames. This
reduced structural integrity can increase loading in the fuselage skin,
which will accelerate skin crack growth and result in rapid
decompression of the fuselage.

DATES: We must receive comments on this proposed AD by July 6, 2010.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the instructions for submitting comments.
     Fax:<PHONE_NUMBER>.
     Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1, fax<PHONE_NUMBER>; e-mail<EMAIL_ADDRESS>
Internet  https://www.myboeingfleet.com. You may review copies of the
referenced service information at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information
on the availability of this material at the FAA, call<PHONE_NUMBER>.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office (telephone<PHONE_NUMBER>) is in the
ADDRESSES section. Comments will be available in the AD docket shortly
after receipt.

FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425)
917-6447; fax<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2010-0481;
Directorate Identifier 2009-NM-192-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.

Discussion

    We have received reports of fatigue cracks found at certain frame
sections, in addition to stub beam cracking, caused by high flight
cycle stresses from both pressurization and maneuver load. Numerous
cracks were found in the shear ties, webs, and inboard and outboard
chords of the overwing body frames and stub beams between body stations
559 and 639. Cracks were also found in the webs, attach angles, and the
upper and lower chords of the stub beams. There were reports of sheared
fasteners in the overwing body frames and stub beams in the same
location.
    Fatigue cracking of certain fuselage frames and stub beams, if not
detected and corrected, and possible severed frames, could result in
reduced structural integrity of the frames. This reduced structural
integrity can increase loading in the fuselage skin, which will
accelerate skin crack growth and result in rapid decompression of the
fuselage.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 737-53-1061, Revision 4,
including Addendum, dated July 16, 1992. For airplanes on which a
repair (Part III) or preventive modification (Part II) has not been
done, the service bulletin describes procedures for

repetitive detailed inspections for cracks and damaged fasteners in the
circumferential frame and the stub beam at body stations 559, 578, 597,
616, and 639, and corrective actions if necessary. For Group 1-3
airplanes, the service bulletin describes procedures for repetitive
eddy current inspections for cracking of the inboard chord fastener
hole of the frame at body station 639, stringer S-16, and corrective
actions if necessary. For airplanes on which certain stub beam lower
chords were installed, the service bulletin describes procedures for an
inspection to determine if a short edge margin exists in the lower
chord and, for airplanes with a certain short edge margin, repetitive
inspections for cracking and corrective actions if necessary. For
airplanes on which either circumferential frame at body station 597 was
changed as given in Boeing Service Bulletin 737-53-1061, Revision 1,
dated December 16, 1983; Revision 2, dated April 18, 1986; or Revision
3, dated June 15, 1989; the service bulletin describes procedures for
repetitive detailed inspections for cracking of the frame.
    This service bulletin also describes a preventive modification,
which would eliminate the need for the repetitive inspections. For
airplanes on which the modification or repair is done at body stations
616 and 639, the service bulletin describes procedures for repetitive
detailed inspections for cracking of the body station 616 and 639 frame
webs and inner and outer chords, near stringer S-16, and corrective
actions if necessary.
    The corrective actions include doing a repair for any cracking and
damaged fasteners that are within the limits specified, replacing a
cracked component by installation of a preventive modification if the
cracks are outside the limits, and contacting Boeing for instructions
if cracks or damaged fasteners cannot be repaired in accordance with
the specified procedures or if the upper chord was replaced at a
certain location.
    For Group 1-3 airplanes, the service bulletin describes procedures
for a modification, which includes reinforcing the body frame inner
chords, replacing the stub beam upper chords and attach angles, and
reinforcing the stub beam web at body stations 597, 616, and 639.

Related Rulemaking

    We are in the process of issuing an AD that refers to Boeing Alert
Service Bulletin 737-53A1254, Revision 1, dated July 9, 2009, and is
related to this proposed AD. That service information applies to Model
737-200, -300, -400, and -500 series airplanes. During review of that
service information it was determined that the same unsafe condition
exists on earlier Boeing Model 737-100 and -200 series airplanes
identified in Boeing Service Bulletin 737-53-1061, Revision 4, dated
July 16, 1992, referred to in this proposed AD as the appropriate
source of service information for accomplishing the actions.

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.
This proposed AD would require accomplishing the actions specified in
the service information described previously, except as discussed under
``Differences Between the Proposed AD and the Service Information.''

Differences Between the Proposed AD and the Service Information

    Although the Accomplishment Instructions of Boeing Service Bulletin
737-53-1061, Revision 4, dated July 16, 1992, include a modification
for Group 4 airplanes (Model 737-200C airplanes), the applicability of
this proposed AD does not include those airplanes. This proposed AD is
applicable to passenger airplanes only.
    The service bulletin also specifies to contact the manufacturer for
instructions on repairing cracks, but this proposed AD would require
repairing cracks in one of the following ways:
     Using a method that we approve; or
     Using data that meet the certification basis of the
airplane, and that have been approved by the Boeing Commercial
Airplanes Organization Delegation Authorization (ODA) that we have
authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD would affect 45 airplanes of U.S.
registry.
    We estimate that it would take about 4 work-hours per product to
comply with the proposed inspections. The average labor rate is $85 per
work-hour. Based on these figures, we estimate the cost of this
proposed inspection to the U.S. operators to be $15,300, or $340 per
product, per inspection cycle.
    We estimate that it would take about 288 work-hours per product to
comply with the proposed modification (for Group 1-3 airplanes). The
average labor rate is $85 per work-hour. Required parts would cost
about $58,742 per product. Based on these figures, we estimate the cost
of this proposed modification to the U.S. operators to be $83,222 per
product.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. ``Subtitle VII: Aviation
Programs,'' describes in more detail the scope of the Agency's
authority.
    We are issuing this rulemaking under the authority described in
``Subtitle VII, Part A, Subpart III, Section 44701: General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.

Regulatory Findings

    We determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not
have a substantial direct effect 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.
    For the reasons discussed above, I certify this proposed
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order
12866,
    2. Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979), and
    3. Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
    You can find our regulatory evaluation and the estimated costs of
compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new AD:

The Boeing Company: Docket No. FAA-2010-0481; Directorate Identifier
2009-NM-192-AD.

Comments Due Date

    (a) We must receive comments by July 6, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 737-100 and -200
series airplanes, certificated in any category; line numbers 1
through 848 inclusive.

Subject

    (d) Air Transport Association (ATA) of America Code 53:
Fuselage.

Unsafe Condition

    (e) This AD results from reports of fatigue cracks at certain
frame sections, in addition to stub beam cracking, caused by high
flight cycle stresses from both pressurization and maneuver load.
The Federal Aviation Administration is issuing this AD to detect and
correct fatigue cracking of certain fuselage frames and stub beams,
and possible severed frames, which could result in reduced
structural integrity of the frames. This reduced structural
integrity can increase loading in the fuselage skin, which will
accelerate skin crack growth and result in rapid decompression of
the fuselage.

Compliance

    (f) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.

Inspections

    (g) For airplanes on which a repair (Part III of the
Accomplishment Instructions of Boeing Service Bulletin 737-53-1061)
or preventive modification (Part II of the Accomplishment
Instructions of Boeing Service Bulletin 737-53-1061) has not been
done in accordance with Boeing Service Bulletin 737-53-1061 as of
the effective date of this AD: Before the accumulation of 15,000
total flight cycles or within 3,000 flight cycles after the
effective date of this AD, whichever occurs later, do the
inspections required by paragraphs (g)(1) and (g)(2) of this AD, in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 737-53-1061, Revision 4, dated July 16, 1992. Repeat the
inspection at the time specified, until the terminating action
required by paragraph (l) of this AD is done.
    (1) Do a detailed inspection (Part I of the Accomplishment
Instructions of Boeing Service Bulletin 737-53-1061) for cracks and
damaged fasteners of the fuselage frames and stub beams. If no crack
or damaged fastener is found, repeat the inspection thereafter at
intervals not to exceed 4,500 flight cycles.
    (2) Do an eddy current inspection (Part IV of the Accomplishment
Instructions of Boeing Service Bulletin 737-53-1061) for cracking of
the inboard chord fastener hole of the frame at body station 639,
stringer S-16. If no crack is found, repeat the inspection
thereafter at intervals not to exceed 15,000 flight cycles.

    Note 1:  Access and restoration instructions, as detailed in the
Accomplishment Instructions of Boeing Service Bulletin 737-53-1061,
Revision 4, dated July 16, 1992, are not required by this AD.
Operators may do those actions in accordance with their maintenance
practices.

    (h) For airplanes on which the body station 597 frame was
changed as of the effective date of this AD, in accordance with the
Accomplishment Instructions of Boeing Service Bulletin 737-53-1061,
dated May 28, 1982; Revision 1, dated December 16, 1983; Revision 2,
dated April 18, 1986; or Revision 3, dated June 15, 1989: Within
3,000 flight cycles after the effective date of this AD, do a
detailed inspection for cracking of the frame, in accordance with
the Accomplishment Instructions of Boeing Service Bulletin 737-53-
1061, Revision 4, dated July 16, 1992. Repeat the detailed
inspection thereafter at intervals not to exceed 4,500 flight
cycles. Installation of new radius fillers in accordance with the
Accomplishment Instructions of Boeing Service Bulletin 737-53-1061,
Revision 4, dated July 16, 1992, terminates the inspections required
by this paragraph.
    (i) For airplanes on which a stub beam lower chord with \1/4\-
inch diameter fasteners at body station 597 is installed as of the
effective date of this AD, in accordance with the Accomplishment
Instructions of Boeing Service Bulletin 737-53-1061, Revision 1,
dated December 16, 1983; Revision 2, dated April 18, 1986; or
Revision 3, dated June 15, 1989: Within 3,000 flight cycles after
the effective date of this AD, do a detailed inspection for short
edge margins. If the short edge margin is determined to be less than
1.5D (diameter), before further flight, do a detailed inspection for
cracking of the stub beam lower chords, in accordance with Boeing
Service Bulletin 737-53-1061, Revision 4, dated July 16, 1992.
Repeat the detailed inspection thereafter at intervals not to exceed
4,500 flight cycles, if the edge margin is less than 1.5D. If the
edge margin is greater than or equal to 1.5D, no further action is
required by this paragraph. Replacing the lower chord in accordance
with Boeing Service Bulletin 737-53-1061, Revision 4, dated July 16,
1992, terminates the repetitive inspections specified in this
paragraph.

Corrective Actions

    (j) Except as required by paragraph (k) of this AD, if any crack
or damaged fastener is found during any inspection required by this
AD, before further flight, repair if cracking and damaged fasteners
are within the specified limits, or do a preventive modification if
cracking or damaged fasteners are outside the specified limits, in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 737-53-1061, Revision 4, dated July 16, 1992.

Exception to Service Information

    (k) Where Boeing Service Bulletin 737-53-1061, Revision 4, dated
July 16, 1992, specifies to contact Boeing for repair instructions:
Before further flight, repair using a method approved in accordance
with the procedures specified in paragraph (n) of this AD.

Terminating Action (Preventive Modification) for Certain Inspections

    (l) Before the accumulation of 75,000 total flight cycles: Do
the preventive modification in accordance with Part II, or repair in
accordance with Part III, of the Accomplishment Instructions of
Boeing Service Bulletin 737-53-1061, Revision 4, dated July 16,
1992. The modification or repair terminates the repetitive
inspection requirements of this AD for the repaired or modified
frame only, except as required by paragraph (m) of this AD.

Post-Modification or Repair Inspections

    (m) For airplanes on which a repair or modification at body
station 616 or 639 is done: Within 24,000 flight cycles after doing
the repair or modification, or within 3,000 flight cycles after the
effective date of this AD, whichever occurs later, do a detailed
inspection for cracking of the BS 616 and 639 frame webs, inner
chord, and outer chord near stringer S-16, in accordance with Boeing
Service Bulletin 737-53-1061, Revision 4, dated July 16, 1992.
    (1) If no cracking is found, repeat the inspection thereafter at
intervals not to exceed 4,500 flight cycles.
    (2) If any cracking is found, before further flight, repair the
cracking using a method approved in accordance with the procedures
specified in paragraph (n) of this AD.

Alternative Methods of Compliance (AMOCs)

    (n)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, has the authority to approve AMOCs for this AD, if requested
using the procedures found in 14 CFR 39.19. Send information to
ATTN: Wayne Lockett, Aerospace Engineer, Airframe Branch, ANM-120S,
FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW.,
Renton, Washington 98057-3356; telephone<PHONE_NUMBER>; fax (425)
917-6590. Or, e-mail information to 9-ANM-Seattle-ACO-AMOC-
<EMAIL_ADDRESS>    (2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
Before using any approved AMOC on any airplane to which the AMOC
applies, notify your principal maintenance inspector (PMI) or
principal avionics inspector (PAI), as appropriate, or lacking a
principal inspector, your local Flight Standards District Office.
The AMOC approval letter must specifically reference this AD.
    (3) An AMOC that provides an acceptable level of safety may be
used for any repair required by this AD, if it is approved by the

Boeing Commercial Airplanes Organization Delegation Authorization
(ODA) that has been authorized by the Manager, Seattle ACO, to make
those findings. For a repair method to be approved, the repair must
meet the certification basis of the airplane.

    Issued in Renton, Washington, on May 5, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2010-11905 Filed 5-18-10; 8:45 am]
BILLING CODE 4910-13-P