Document ID: EPA-R05-OAR-2021-0536-0040
Agency: epa
Document Type: Rule
Title: Final Approval of the Detroit, Michigan SO2 Federal Implementation Plan
Posted Date: 2022-10-12T04:00Z

[Federal Register Volume 87, Number 196 (Wednesday, October 12, 2022)]
[Rules and Regulations]
[Pages 61514-61531]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-21662]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R05-OAR-2021-0536; FRL-9802-02-R5]

Approval and Promulgation of Air Quality Implementation Plans; 
Michigan; Federal Implementation Plan for the Detroit Sulfur Dioxide 
Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is promulgating a 
Federal Implementation Plan (FIP) for attaining the 2010 sulfur dioxide 
(SO2) primary national ambient air quality standard (NAAQS) 
for the Detroit SO2 nonattainment area. The FIP includes an 
attainment demonstration and other elements required under the Clean 
Air Act (CAA). In addition to an attainment demonstration, the FIP 
addresses the requirement for meeting reasonable further progress (RFP) 
toward attainment of the NAAQS, reasonably available control measures 
and reasonably available control technology (RACM/RACT), enforceable 
emission limitations and control measures to provide for NAAQS 
attainment, and contingency measures. This action supplements a prior 
action which found that Michigan had satisfied emission inventory and 
nonattainment new source review (NSR) requirements for this area but 
had not met requirements for the elements addressed in the FIP. The FIP 
provides for attainment of the 2010 primary SO2 NAAQS in the 
Detroit SO2 nonattainment area and meets the other 
applicable requirements under the CAA.

DATES: This final rule is effective on November 14, 2022.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-R05-OAR-2021-0536. All documents in the docket are listed on 
the www.regulations.gov website. Although listed in the index, some 
information is not publicly available, i.e., Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only in hard 
copy form. Publicly available docket materials are available either 
through www.regulations.gov or at the Environmental Protection Agency, 
Region 5, Air and Radiation Division, 77

[[Page 61515]]

West Jackson Boulevard, Chicago, Illinois 60604. This facility is open 
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding Federal 
holidays and facility closures due to COVID-19. We recommend that you 
telephone Abigail Teener, Environmental Engineer, at (312) 353-7314 
before visiting the Region 5 office.

FOR FURTHER INFORMATION CONTACT: Abigail Teener, Environmental 
Engineer, Attainment Planning and Maintenance Section, Air Programs 
Branch (AR18J), Environmental Protection Agency, Region 5, 77 West 
Jackson Boulevard, Chicago, Illinois 60604, telephone number: (312) 
353-7314, email address: [email protected].

SUPPLEMENTARY INFORMATION:

I. Background Information

    Following the promulgation in 2010 of a 1-hour primary 
SO2 NAAQS, on August 5, 2013, EPA designated the Detroit 
area within the State of Michigan as nonattainment for this NAAQS, in 
conjunction with designating multiple areas in other states as 
nonattainment (78 FR 47191).
    For a number of nonattainment areas, including the Detroit area, 
EPA published an action on March 18, 2016, effective April 18, 2016, 
finding that Michigan and other pertinent states had failed to submit 
the required SO2 nonattainment plan by the submittal 
deadline (81 FR 14736). This finding initiated a deadline under CAA 
section 179(a) for the potential imposition of 2-to-1 NSR offset and 
Federal highway funding sanctions. Additionally, under CAA section 
110(c), the finding triggered a requirement that EPA promulgate a FIP 
within two years of the finding unless, by that time, (a) the state had 
made the necessary complete submittal, and (b) EPA had approved the 
submittal as meeting applicable requirements.
    Michigan submitted the Detroit SO2 attainment plan on 
May 31, 2016, and submitted associated final enforceable measures on 
June 30, 2016. Michigan's submission of a complete attainment plan 
terminated the deadlines for imposing the 2-to-1 NSR offset sanctions 
and Federal highway funds sanctions, pursuant to 40 CFR 52.31(d)(5), 
but it did not terminate EPA's FIP obligation. On March 19, 2021, EPA 
partially approved and partially disapproved Michigan's SO2 
plan as submitted in 2016 (86 FR 14827). EPA approved the base-year 
emissions inventory and affirmed that the NSR requirements for the area 
had previously been met on December 16, 2013 (78 FR 76064). EPA also 
approved the enforceable control measures for two facilities. At that 
time, EPA disapproved the attainment demonstration, as well as the 
requirements for meeting RFP toward attainment of the NAAQS, RACM/RACT, 
and contingency measures. Additionally, EPA disapproved the plan's 
control measures for two facilities as insufficient to demonstrate 
attainment. These disapprovals triggered new sanctions clocks under CAA 
section 179(a).
    As Michigan has not submitted an approvable plan for the Detroit 
nonattainment area, EPA published a notice of proposed rulemaking on 
June 1, 2022, proposing a FIP for the Detroit nonattainment area (87 FR 
33095). EPA proposed limits and associated requirements for U.S. Steel 
(Ecorse and Zug Island), EES Coke, Cleveland-Cliffs Steel Corporation 
(formerly AK or Severstal Steel), and Dearborn Industrial Generation 
(DIG). EPA also proposed to include in its analysis the Carmeuse Lime 
emission limits specified in Permit to Install 193-14A and the DTE 
Energy (DTE) Trenton Channel emission limits specified in Permit to 
Install 125-11C, which had already been incorporated into Michigan's 
SIP.
    EPA proposed to conclude that the FIP meets the requirements set 
forth in the CAA to provide for the Detroit area to attain the 
SO2 NAAQS. Finally, EPA proposed to conclude that the FIP 
satisfies the other applicable requirements for nonattainment areas, 
including requirements for RACM/RACT, RFP, and contingency measures. 
The proposal supplemented the previous action in which EPA concluded 
that Michigan had met the requirements for a suitable emissions 
inventory and nonattainment NSR program.

II. Public Comments

    The comment period on the proposed action described above closed on 
July 18, 2022. EPA held a virtual public hearing on June 16, 2022. The 
transcript of the public hearing is available in the docket for this 
action. EPA received 14 written comments, seven of which were 
supportive and seven of which were adverse. EPA also received verbal 
comments from four individuals at the public hearing, all of which were 
adverse or partially adverse comments. The adverse comments are 
summarized below along with EPA's responses.
    Comment: The commenters contend that EPA's modeling demonstration 
has not correctly accounted for all the SO2 sources in the 
area as well as short-term spikes in emissions. In particular, the 
commenters suggest that EPA did not sufficiently account for the 
Marathon Refinery emissions, as they were calculated using maximum heat 
input multiplied by emissions factors. The commenters stated that 
emission factors, particularly AP-42 emission factors, are intended to 
calculate average emission levels and are not appropriate for 
calculating modeling inputs to address the short-term SO2 
NAAQS. The commenters recommend EPA use another method for calculating 
Marathon Refinery emissions, such as continuous emissions monitoring, 
stack testing, vendor guarantees and stack testing data from similar 
facilities, material balance calculations, or optical remote sensing.
    Response: Section 8.2.2.b of EPA's Guideline on Air Quality Models 
(appendix W to 40 CFR part 51) (appendix W) requires regulatory 
modeling of inert pollutants such as SO2 to use the emission 
input data given in Table 8-1 of appendix W. For stationary point 
sources subject to SIP emission limit evaluation for compliance with 
short-term standards such as the 1-hour SO2 NAAQS, the 
modeled emission rate is required to be based on the maximum allowable 
emission limit or federally enforceable permit limit, on actual or 
design capacity of the point source (whichever is greater) or federally 
enforceable permit conditions, and on continuous operation for all 
hours of each time period under consideration.
    As stated in the technical support document (included in the docket 
for this action), Marathon Refinery's emission units were modeled based 
on maximum uncontrolled emissions--a rate that is higher, and 
consequently more conservative in avoiding underestimation of 
emissions, than would be a limited emission rate. The maximum 
uncontrolled emission rates for Marathon Refinery were determined based 
on the maximum heat input of each modeled point source and emission 
factors derived from the hydrogen sulfide (H2S) and total 
reduced sulfur (TRS) concentration of the refinery fuel gas combusted 
in each emission unit. The H2S/TRS concentration of the fuel 
gas is a representative source-specific concentration that was used to 
determine a source-specific emission factor as opposed to an AP-42 
emission factor that may be determined based on average emissions 
across different facilities.
    Additionally, the commenters recommend different methods for 
estimating short-term emissions instead of using the source-specific 
emission factor used in the modeling, including continuous emissions 
monitoring, stack

[[Page 61516]]

testing, vendor guarantees and stack testing data from similar 
facilities, material balance calculations, or optical remote sensing. 
All of these methods would be suitable for determining actual 
emissions. However, EPA's modeling instead accounts for maximum 
uncontrolled emissions, which are higher and more conservative than 
actual emissions, based on each emission unit's maximum capacity and 
combusted fuel gas. Therefore, EPA believes it has appropriately 
modeled the emissions for Marathon Refinery.
    Comment: Five commenters commented on the background concentration 
used in the model. Three commenters believe that the background 
concentration used in EPA's modeling analysis may be underestimated. To 
avoid double-counting concentrations associated with sources explicitly 
modeled in the demonstration, EPA's background concentration 
calculation was derived by removing wind directions between 40 and 205 
degrees, which the commenters contend is overly broad and eliminates 
the highest concentrations that come from the easterly winds. In 
particular, a commenter states that Michigan's original background 
concentration calculation approach excluded wind directions between 40 
and 180 degrees, and then Michigan later changed its approach, which 
EPA adopted, to removing wind directions between 40 and 205 degrees 
without adequate justification. A commenter suggests that sources in 
Ohio, western Pennsylvania, Indiana, Kentucky, Illinois, eastern 
Michigan, and Canada, some of which are relatively close and emit much 
more SO2 than the background sources that EPA considers, 
should be included in the background concentration. The commenter 
states that although SO2 concentrations decline with 
distance, they can still remain significant with respect to the 
difference between the maximum modeled concentration and the NAAQS.
    One commenter contends that the FIP does not adequately justify the 
approach for the Detroit SO2 nonattainment area given the 
large number of SO2 sources. Additionally, the commenter 
points out that EPA based its approach for calculating background 
concentrations on EPA guidance for calculating NOX 
background concentrations, which may not be appropriate for 
SO2.
    The commenters also state that the uncertainty of the background 
estimate was not provided, and the fact that the approach depends on 
the meteorological and monitoring data used, the definition of the wind 
sector, the wind sector width, and year and seasons considered adds to 
this uncertainty. The commenters also state that the error is higher at 
lower concentrations, which should be considered. The commenters note 
that an accurate background concentration calculation is critical given 
that the maximum modeled concentration is very close to the NAAQS.
    Additionally, one commenter alleges that the meteorological data at 
the Allen Park site is not representative due to trees near the site 
that shelter the tower because they exceed its height. The commenter 
states that the wind directions at Allen Park diverge from other 
Michigan sites and recommend that EPA use airport data instead.
    The commenters recommend that EPA perform trajectory analyses to 
eliminate the possibility that concentrations at the endpoints of the 
exclusion are due to extreme meteorology instead of stationary sources, 
analyze different exclusion ranges, and make conservative assumptions 
to minimize modeling uncertainties. One commenter recommends that EPA 
model background estimates using the largest sources within 500 
kilometers, use other monitoring sites, which may include using sites 
classified as ``source'' or ``population'' instead of ``background'' 
and/or deploying additional monitoring sites, and use a meaningful 
margin of error to account for model uncertainty in the background 
concentration analysis.
    However, two commenters contend that the background concentration 
that EPA used was overly conservative and reflects an overestimate of 
background concentrations, as the maximum background concentration used 
in the model (11.9 parts per billion (ppb)) occurs around the 33-degree 
wind direction, which is directly over a source that was explicitly 
modeled in the demonstration and near other sources. One commenter 
points out that the Trinity monitor, which is upstream of these 
sources, recorded a concentration of 0.7 ppb for the same hour that was 
used for the maximum background concentration.
    Response: Sections 8.3.1.a and 8.3.3 of appendix W discusses that 
background air quality should not include the ambient impacts of the 
project source under consideration. Appendix W further states that 
nearby sources that cause a significant concentration gradient in the 
vicinity of the source(s) under consideration for emissions should not 
be included in the background monitoring data and should be explicitly 
modeled. The portion of the background attributable to natural sources, 
other unidentified sources near the project, and regional transport 
from distant sources, both domestic and international, can be 
represented by air quality monitoring data. Per Table 8-1 of appendix 
W, these other sources include both minor sources and distant major 
sources. Section 8.3.2.b of appendix W states that EPA recommends the 
use of data from the monitor closest to and upwind of the project area. 
Section 8.3.2.c of appendix W also discusses that there are cases in 
which the current design value may not be appropriate for use as a 
background concentration, including situations with a modifying source 
where the existing facility is determined to impact the ambient 
monitor. In these cases, the background concentration can be determined 
by excluding values when the source in question is impacting the 
monitor.
    In the case of the analysis for the Detroit SO2 
nonattainment area, monitor values from the Allen Park monitor (AQS 26-
163-0001) that occurred when the wind directions were between 40 and 
205 degrees were removed from the calculations for the background 
concentration. The Allen Park monitor is on the western boundary of the 
Detroit SO2 nonattainment area and is upwind of the 
explicitly modeled sources in the analysis due to predominant 
southwesterly winds. The directions between 40 and 205 were chosen as 
concentrations from these directions would be double counting the 
impacts from the explicitly modeled sources within the analysis. This 
excludes all modeled sources to the northeast (U.S. Steel, EES Coke, 
Carmeuse Lime, Marathon Refinery, Cleveland-Cliffs Steel Corporation, 
and DIG) and modeled sources to the south (DTE Trenton Channel and DTE 
Monroe). Examining the meteorological data collected from the Allen 
Park monitor, the highest concentrations measured at the monitor occur 
when the winds are from the northeast, which suggests that the monitor 
is being impacted by SO2 emission sources from the Detroit 
area that are already included in the modeling analysis. Section 
8.3.2.c.i of appendix W discusses that a 90-degree sector downwind of 
the source(s) may be used to determine the area of impact. In the case 
of the Detroit nonattainment area, EPA did not exclude 45 degrees to 
the west of the northernmost sources. EPA did exclude 45 degrees west 
of the southern source that is farther from the monitor and for which 
there would be more plume spread by the time SO2 reaches the 
Allen Park monitor.

[[Page 61517]]

    SO2 is a localized, source-oriented pollutant, as 
described in section III of EPA's final rule revising the 
SO2 NAAQS (75 FR 35520) and section 4.2.3.3 of appendix W. 
Section 8.3.3.d of appendix W states that portions of the background 
attributable to all other sources (e.g., natural sources, minor and 
distant major sources) should be accounted for through use of ambient 
monitoring data and determined by the procedures found in section 8.3.2 
in keeping with eliminating or reducing the source-oriented impacts 
from nearby sources to avoid potential double-counting of modeled and 
monitored contributions. As section 8.3.3.d of appendix W describes, 
background concentrations inherently account for the impacts of minor 
and distant major sources with the use of appropriate monitoring data. 
Due to the localized nature of SO2, impacts from localized 
sources are accounted for by either explicitly modeling these as nearby 
sources in the modeling analysis or through ambient air monitoring 
data. As localized sources were explicitly modeled as nearby sources in 
the analysis, and the referred guidance above was followed, EPA 
disagrees with the commenter that sources outside of the nonattainment 
area should be explicitly included in the background concentration as 
these would already be accounted for in the background concentration.
    EPA disagrees with the commenter that the FIP does not adequately 
justify the approach for the Detroit SO2 nonattainment area 
given the large number of SO2 sources and that the 
background calculations relied on EPA guidance. Section 8.1 of EPA's 
SO2 NAAQS Designations Modeling Technical Assistance Document (TAD), 
which was most recently updated in August 2016, discusses how the 
methodology for calculating NOX background concentrations 
applies to SO2. The TAD explains that the same methodology 
for NOX is applicable to SO2 designations 
modeling based on use of the 99th percentile by hour of day and season 
for background concentration excluding periods when the dominant 
source(s) are influencing the monitored concentration.\1\
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    \1\ See TAD, page 30. The TAD can be found at https://www.epa.gov/so2-pollution/technical-assistance-documents-implementing-2010-sulfur-dioxide-standard.
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    EPA agrees that an accurate background concentration is critical. 
EPA has accurately calculated background concentrations from the hourly 
monitoring data collected at the Allen Park ambient air monitoring 
station based on guidance from EPA's TAD and appendix W. An uncertainty 
analysis for background estimates is not required for regulatory air 
dispersion modeling analyses and therefore, was not provided in the 
technical support document for this action.
    EPA disagrees that the meteorological data at the Allen Park site 
is not representative and that meteorological data from the airport 
should be used instead. The Allen Park monitoring site is an NCore 
monitoring site for the state of Michigan that also collects 
meteorological data. When comparing the wind roses of the Detroit 
Metropolitan Wayne County Airport (DTW) 2016-2020 wind data and the 
Allen Park 2018-2020 wind data, the wind roses are very similar in wind 
direction frequency and wind speed classes. One difference between the 
two sites is the prevalence of winds from the south/southwest (SSW), in 
which DTW experiences more frequent SSW winds than the Allen Park site. 
However, the sites experience similar easterly winds. As such, the 
trees near the Allen Park monitoring site are not causing the wind 
directions to diverge from the airport site; therefore, the wind 
measurements from the DTW airport should not be used instead. EPA also 
verified with Michigan that all monitors and meteorological instruments 
at the Allen Park monitoring site meet EPA's siting criteria. This 
monitoring site is subject to EPA audits and siting criteria are 
frequently checked and confirmed.
    EPA disagrees that trajectory analyses need to be performed and 
that different exclusion ranges need to be examined. Pollution roses 
from the Allen Park monitor were examined by Michigan in the 
development of the background concentration. Pollution roses consider 
hourly meteorological conditions and ranges of wind directions in which 
SO2 concentrations impact the monitor site. As was 
demonstrated by Michigan, the range of exclusion used in the FIP 
modeling analysis is acceptable as the pollution rose demonstrates that 
the Allen Park monitor was impacted by explicitly modeled nearby 
sources in this wind direction range. Therefore, trajectory analyses 
are not required for this analysis.
    EPA disagrees with the commenter that modeled background estimates 
should be used to determine the background concentrations for the 
modeling analysis. Section 8.3.2.b of appendix W states that in most 
cases, EPA recommends using data from the monitor closest to and upwind 
of the project area. If several monitors are available, preference 
should be given to the monitor with characteristics that are most 
similar to the project area. The Allen Park monitor was chosen as a 
representative monitor for background concentrations for the Detroit 
nonattinment area due its location within the SO2 
nonattainment boundary and prevailing southwest winds that make the 
monitor upwind of Detroit.
    EPA disagrees that the background concentrations are overly 
conservative; as explained above, EPA has followed relevant EPA 
guidance in determining background concentrations. EPA did exclude 
SO2 concentrations from northeast of the Allen Park monitor 
based on data from the SO2 pollution roses for the Allen 
Park monitor. These excluded impacts from explicitly modeled nearby 
sources in the modeling analysis to prevent double-counting impacts. 
EPA did not exclude 45 degrees to the west of the northernmost sources 
for the background concentration as plume spread from these sources 
would not have as great of an impact as more distant emission sources. 
Therefore, the exclusion range sufficiently excludes nearby sources in 
the area.
    Comment: Four commenters commented on EPA's usage of rural 
dispersion coefficients as part of the modeling analysis. EPA used 
rural dispersion coefficients to characterize three tall stacks in the 
modeling analysis to better correlate the modeled concentrations with 
modeling concentrations at two monitors in the Detroit nonattainment 
area. The commenters state that the heat island effect can cause higher 
concentrations during the night, which is shown with the urban 
coefficient option. The commenters recommend additional analysis to 
determine whether the SO2 temporal distribution at the 
monitors can be extrapolated to the area of maximum SO2 
concentration near DTE Trenton Channel.
    The commenters raise concern that the use of a rural dispersion 
coefficient for stacks at EES Coke, DTE Monroe, DTE River Rouge, and 
DTE Trenton Channel leads to significantly lowered predicted 
concentrations. The commenters claim that EPA did not properly document 
its model performance evaluation to support the claim that applying a 
rural dispersion coefficient to the listed sources was the most 
appropriate way to run the model. The commenters state that if EPA had 
properly applied an urban dispersion coefficient to the sources, the 
area could not model attainment.
    Response: EPA agrees that the urban heat island effect can in some 
cases cause higher concentrations during the night. However, as was 
demonstrated in

[[Page 61518]]

the document entitled ``Analysis of Michigan Dispersion Coefficient 
Use'' and the technical support document, both included in the docket 
for this action, this was not the case when examining monitoring data 
in the Detroit nonattainment area for the Southwest High School and 
West Windsor monitors. Monitoring data from these monitors demonstrated 
that peak monitored impacts occurred during the daytime (between 12:00 
p.m.-3:00 p.m.) instead of at night. As described in the AERMOD 
Implementation Guide,\2\ plumes from tall buoyant stacks, transported 
over the urban boundary layer at night, may be unaffected by the urban 
enhanced dispersion and may require special consideration on a case-by-
case basis. The urban dispersion option in AERMOD only applies to 
nighttime and morning transition hours. Nighttime hours would normally 
be stable if not for the urban heat island effect, and the morning 
transition hours right after sunrise, when the atmosphere would 
transition from stable to convective conditions in a rural setting, 
might be more convective in urban conditions. Both monitored data at 
the Southwest High School and West Windsor sites, as well as modeled 
concentrations using the rural option for these stacks, showed peak 
concentrations outside of the nighttime and morning transition hours, 
which indicate the rural dispersion option is more appropriate for this 
set of stacks in this analysis.
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    \2\ See AERMOD Implementation Guide, pages 19-20, which can be 
found at https://gaftp.epa.gov/Air/aqmg/SCRAM/models/preferred/aermod/aermod_implementation_guide.pdf.
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    EPA disagrees with the commenters that EPA did not properly 
document the model performance evaluation. Section 7.2.1.1.e of 
appendix W states that model users should consult with the appropriate 
reviewing authority and the latest version of the AERMOD Implementation 
Guide when evaluating this situation. Further, Section 5.1 of the 
AERMOD Implementation Guide states that a more thorough case-specific 
justification will be needed to support excluding elevated sources from 
application of the urban option.\3\ As these guidance documents state, 
a case-specific justification needs to be provided to support the 
exclusion of these stacks from the urban option, and the case-specific 
justification was provided within the technical support document as 
well as the document ``Analysis of Michigan Dispersion Coefficient 
Use,'' which are both in the docket for this action. These documents 
demonstrated that the application of the urban option to the tall 
stacks at EES Coke, DTE Monroe, DTE River Rouge, and DTE Trenton 
Channel resulted in anomalously high concentrations due to plume height 
limitations in the model. As such, additional analysis is also not 
warranted to determine if the temporal distribution can be extrapolated 
to the DTE Trenton facility.
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    \3\ See the AERMOD Implementation Guide, page 20, which can be 
found at https://gaftp.epa.gov/Air/aqmg/SCRAM/models/preferred/aermod/aermod_implementation_guide.pdf.
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    Comment: The commenter raises concern that the 50 kilometer 
distance from the nonattainment area is an inadequate cutoff for 
including major point sources. The commenter states that there are a 
number of large sources just beyond this distance that are not included 
in the background concentration.
    Response: EPA disagrees that the 50 kilometer distance from the 
nonattainment area is an inadequate cutoff for including major point 
sources. EPA used the maximum distance (50 kilometers) from the 
nonattainment area in its modeling analysis. Section 4.1.c of appendix 
W explains that due to the steady-state assumption, Gaussian plume 
models are generally considered applicable to distances less than 50 
kilometers, beyond which, modeled predictions of plume impact are 
likely conservative. As such, AERMOD is not recommended for use in far-
field (greater than 50 kilometers) dispersion applications. Since 
SO2 is a source-oriented pollutant and not considered a 
regional pollutant for regulatory purposes, it is not appropriate to 
model beyond 50 kilometers. In this case, EPA explicitly modeled DTE 
Monroe, a source outside of the nonattainment area, in addition to the 
sources within the nonattainment area as a conservative measure. Please 
also refer to the responses above regarding background concentrations, 
specifically the response to comments about sources beyond 50 
kilometers being included in the modeling analysis and background 
concentration.
    Comment: The commenter states that EPA's modeling lacks 
transparency and detail, as EPA did not provide sufficient maps and 
tabular data, SO2 levels throughout the nonattainment area, 
and information pertaining to understanding spatial and temporal 
exposure variation, locations of impacts, critical meteorological 
factors, culpable sources, background levels, etc.
    Response: EPA's modeling analysis is available in the technical 
support document, which is included in the docket for this action. In 
the technical support document, EPA provided maps of the areas of 
maximum concentration, as well as the modeling parameters used in the 
area of analysis, including background concentrations. As the focus of 
this action is to demonstrate attainment of the NAAQS, and the 
technical support document demonstrates that the areas of maximum 
concentration are below the NAAQS, EPA did not provide maps of 
SO2 concentrations throughout the nonattainment area. 
However, EPA's modeling files are available to the public upon request. 
The maximum modeled concentration, including background concentrations, 
was 73.6 ppb and occurred approximately 4 kilometers to the northwest 
of DTE Trenton Channel's facility. Other modeled concentrations that 
were less than the maximum modeled design value at receptors in the 
nonattainment area were 71.5 ppb to the northeast of Cleveland-Cliffs 
Steel Corporation and DIG, 73.2 ppb on the northern fenceline of Zug 
Island (when U.S. Steel's Zug Island sources are in operation), and 
68.7 ppb to the northeast of Carmeuse Lime.
    Comment: EPA received three comments regarding the FIP's margin of 
safety and the health effects of SO2, particularly for 
children in Detroit. The commenters state that the FIP does not provide 
an uncertainty analysis. The commenters contend that as the maximum 
modeled concentration is so close to the NAAQS (73.4 ppb compared to 75 
ppb), the FIP does not provide any margin of safety. The commenters 
state that the model cannot be considered conservative due to likely 
background concentration underprediction, the use of rural dispersion 
coefficients, and longer-term average emission rates. The commenters 
recommend that EPA either validate the model using the monitoring data 
from the SO2 monitoring sites in the Detroit nonattainment 
area or set limits that produce modeled SO2 concentrations 
well below the NAAQS.
    The commenters argue that the NAAQS itself is not protective, as a 
health study of children in Detroit shows that 1-hour maximum 
SO2 exposures were associated with increased odds of 
respiratory symptoms, even though the levels of SO2 that the 
children were exposed to were generally below the NAAQS. One commenter 
states that children in Detroit have breathing issues due to pollution 
that cause them to miss school and cited a study that shows Southwest 
Detroit has some of the worst air pollution in the country. The 
commenters note that Detroit communities experience asthma rates that 
are 1.5-3 times the national average along with low rates of asthma

[[Page 61519]]

controller utilization due to health care access, poverty, and 
caregiver issues.
    Response: As described further in comment responses below, under 
section 109 of the CAA, EPA sets primary, or health-based, NAAQS for 
all criteria pollutants to provide requisite protection of public 
health, including the health of at-risk populations, with an adequate 
margin of safety. The health effects information provided by the 
commenters, which was addressed in EPA's promulgation of the 2010 
SO2 NAAQS, is not in dispute in this rulemaking, and EPA in 
this action is not reopening the NAAQS itself which was established to 
protect public health with an adequate margin of safety. This 
rulemaking instead addresses the requirements needed for the Detroit 
area to meet the NAAQS. However, EPA is aware of the demographic data 
for the Detroit nonattainment area, and that the Detroit nonattainment 
area includes communities that are pollution-burdened and underserved, 
and environmental justice concerns are addressed in comment responses 
below.
    EPA disagrees that the model cannot be considered conservative. In 
its modeling analysis, EPA used the maximum uncontrolled or maximum 
allowable emission rates for all sources in the Detroit nonattainment 
area. In reality, it is extremely unlikely that all sources would be 
operating at maximum emission rates simultaneously. Additionally, EPA's 
method of background concentration calculation, use of rural dispersion 
coefficients, and reliance on longer-term average emission rates follow 
EPA guidance and are appropriate for demonstrating attainment of the 
NAAQS, as explained in comment responses above and below.
    Comment: Three commenters state that a taller combined stack at 
U.S. Steel will not significantly decrease SO2 
concentrations that affect public health in residential areas downwind 
of the facility.
    Response: While EPA acknowledges that combining and raising the 
U.S. Steel Boilerhouse 2 stack will only decrease near-field 
SO2 concentrations where current ambient concentrations 
threaten the NAAQS, EPA is requiring this stack construction in 
combination with new limits at U.S. Steel, a facility that has not 
previously had hourly SO2 limits. Both of these control 
mechanisms are needed to ensure that the SO2 concentrations 
in the Detroit area, including those in residential areas downwind of 
the facility, stay permanently below the NAAQS and result in protection 
of public health with an adequate margin of safety.
    Comment: The commenters contend that long-term average limits alone 
do not provide for attainment of the one-hour SO2 NAAQS, as 
30-day average limits allow sources to operate at higher levels before 
and after shutdowns and remove incentives for sources to avoid 
malfunctions. The commenters believe that a long-term average limit 
should have supplemental limits governing the magnitude and frequency 
of short-term periods of emissions above the emission rate at which the 
longer-term average limit is set. Additionally, the commenters contend 
that EPA's use of national average adjustment factors for the DIG and 
Cleveland-Cliffs Steel Corporation 24-hour average limits is not 
justified.
    Response: EPA disagrees with the commenter's statement that longer-
term average limits alone do not provide for attainment of the 1-hour 
SO2 NAAQS. EPA believes as a general matter that properly 
set, longer-term average limits are comparably effective in providing 
for attainment of the 1-hour SO2 standard as are 1-hour 
limits. On April 23, 2014, EPA issued recommended guidance for meeting 
the statutory requirements in SO2 nonattainment plans, in a 
document entitled, ``Guidance for 1-Hour SO2 Nonattainment 
Area SIP Submissions'' (2014 SO2 Guidance).\4\ EPA's 2014 
SO2 Guidance sets forth in detail the reasoning supporting 
its conclusion that the distribution of emissions that can be expected 
in compliance with a properly set longer-term average limit is likely 
to yield overall air quality protection that is as good as a 
corresponding hourly emissions limit set at a level that provides for 
attainment. EPA's 2014 SO2 Guidance specifically addressed 
this issue as it pertains to requirements for attainment demonstrations 
for SO2 nonattainment areas under the 2010 NAAQS, especially 
with regard to the use of appropriately set comparably stringent 
limitations based on averaging times as long as 30 days. EPA found that 
a longer-term average limit which is comparably stringent to a short-
term average limit is likely to yield comparable air quality; and that 
the net effect of allowing emissions variability over time but 
requiring a lower average emission level is that the resulting worst-
case air quality is likely to be comparable to the worst-case air 
quality resulting from the corresponding higher short-term emission 
limit without variability. See 2014 SO2 Guidance.
---------------------------------------------------------------------------

    \4\ See https://www.epa.gov/sites/production/files/2016-06/documents/20140423guidance_nonattainment_sip.pdf.
---------------------------------------------------------------------------

    Any accounting of whether a 30-day average limit provides for 
attainment must consider factors reducing the likelihood of hourly 
exceedances as well as factors creating a risk of additional 
exceedances. To facilitate this analysis, EPA used the concept of a 
critical emission value (CEV) for the SO2-emitting 
facilities which are being addressed in a nonattainment plan. The CEV 
is the continuous 1-hour emission rate which is expected to provide for 
the average annual 99th percentile maximum daily 1-hour concentration 
to be at or below 75 ppb, which in a typical year means that fewer than 
four days have maximum hourly ambient SO2 concentrations 
exceeding 75 ppb. See 2014 SO2 Guidance. EPA recognizes that 
a 30-day limit can allow occasions in which emissions exceed the CEV, 
and such occasions yield the possibility of hourly exceedances 
occurring that would not be expected if emissions were always at the 
CEV. At the same time, the establishment of the 30-day average limit at 
a level below the CEV means that emissions must routinely be lower than 
they would be required to be with a 1-hour emission limit at the CEV.
    The proposed FIP provides an illustrative example of the effect 
that application of a limit with an averaging time longer than one hour 
can have on air quality.\5\ This example illustrates both (1) the 
possibility of elevated emissions (emissions above the CEV) causing 
exceedances not expected with emissions at or below the CEV and (2) the 
possibility that the requirement for routinely lower emissions would 
result in avoiding exceedances that would be expected with emissions at 
the CEV. In this example, moving from a 1-hour limit to a 30-day 
average limit results in one day that exceeds 75 ppb that would 
otherwise be below 75 ppb, one day that is below 75 ppb that would 
otherwise be above 75 ppb, and one day that is below 75 ppb that would 
otherwise be at 75 ppb. In net, the 99th percentile of the 30-day 
average limit scenario is lower than that of the 1-hour limit scenario, 
with a design value of 67.5 ppb rather than 75 ppb. Stated more 
generally, this example illustrates several points: (1) The variations 
in emissions that are accounted for with a longer-term average limit 
can yield higher concentrations on some days and lower concentrations 
on other days, as determined by the factors influencing dispersion on 
each day, (2) one must

[[Page 61520]]

account for both possibilities, and (3) accounting for both effects can 
yield the conclusion that a properly set longer-term average limit can 
provide as good or better air quality than allowing constant emissions 
at a higher level. As noted in the proposed FIP, and as described in 
appendix B of the 2014 SO2 guidance, EPA expects that an 
emission profile with a comparably stringent 30-day average limit is 
likely to have a net effect of having a lower number of exceedances and 
better air quality than an emissions profile with maximum allowable 
emissions under a 1-hour emission limit at the critical emission value. 
Thus, EPA continues to assert that appropriately set 30-day emission 
limits can be protective of the 1-hour SO2 standard.
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    \5\ For the full discussion of the hypothetical example, see the 
proposed FIP, June 1, 2022 (87 FR 33095) at page 33100 at https://www.regulations.gov, Docket ID Number EPA-R05-OAR-2021-0536.
---------------------------------------------------------------------------

    The long-term average limits included in the FIP are for a period 
of 30 days for DTE Trenton Channel and 24 hours for DIG and Cleveland-
Cliffs Steel Corporation. As stated above, EPA posits that limits based 
on periods of as long as 30 days (720 hours), determined in accordance 
with EPA's April 2014 guidance, can, in many cases, be reasonably 
considered to provide for attainment of the 2010 SO2 NAAQS. 
Since 30 days for DTE Trenton Channel and 24 hours for DIG and 
Cleveland-Cliffs Steel Corporation are equal to or well within, 
respectively, the period of 30 days, EPA has concluded that a limit 
based on a period of 30 days for DTE Trenton Channel and limits based 
on a period of 24 hours for DIG and Cleveland-Cliffs Steel Corporation 
determined in accordance with EPA's April 2014 guidance can be 
reasonably considered to provide for attainment. While the longer-term 
averaging limits allow occasions in which emissions may be higher than 
the level that would be allowed with the 1-hour limit, the limits 
compensate by requiring average emissions to be adequately lower than 
the level that would otherwise have been required by a 1-hour average 
limit.
    As noted by the commenters, EPA's April 2014 guidance addresses the 
use of supplemental short-term limits. While supplemental limits can 
further strengthen the justification for the use of longer-term limits, 
they are not necessary to provide for attainment of the 2010 
SO2 NAAQS. In this case, as discussed further below, DTE 
Trenton Channel has been permanently shut down during the comment 
period for this action, and DIG and Cleveland-Cliffs Steel Corporation 
are not the primary contributors to the areas of maximum modeled 
concentrations. Therefore, EPA is not considering supplemental limits 
for DTE Trenton Channel, DIG, or Cleveland-Cliffs at this time.
    Regarding the adjustment factors used for the daily DIG and 
Cleveland-Cliffs limits, EPA believes that the appendix D ratios are 
acceptable adjustment factors in this specific situation for use in 
calculating a long-term average emission limit when hourly 
SO2 emissions data are not available for use in calculating 
source-specific emission ratios. Although these daily limits are 
included in the FIP, EPA is not relying on emission reductions from 
either DIG or Cleveland-Cliffs Steel Corporation to demonstrate 
attainment of the 2010 SO2 NAAQS. Rather, EPA has included 
these limits in the FIP to ensure that SO2 concentrations in 
the Detroit area stay permanently below the NAAQS. Since these sources 
are not the controlling sources with respect to the attainment 
demonstration, reliance on the default adjustment factors to account 
for the emissions variability provides a suitable estimate in this 
instance where no other data is available.
    For the reasons stated above and in the proposed rule, EPA 
concludes that the use of long-term average emission limits for DTE 
Trenton Channel, DIG, and Cleveland-Cliffs Steel Corporation is 
consistent with recommendations discussed in EPA's April 2014 guidance 
and adequately protects against violations of the 1-hour SO2 
NAAQS.
    Comment: The commenters disagree with EPA's interpretation of RACT 
for SO2 as the control technology necessary to achieve the 
NAAQS and point out that RACT has been defined for other pollutants as 
the lowest emission limit that is reasonably available considering 
technological and economic feasibility. The commenters contend that the 
U.S. Steel emission limits do not achieve a reduction in 
SO2, as the maximum allowable annual emissions, assuming 
maximum operation for every hour in a year, are higher than U.S. 
Steel's past annual emissions. The commenters believe that EPA should 
consider alternatives to the requirement for combining and raising the 
U.S. Steel Boilerhouse 2 stacks as well as complete a RACT analysis 
considering technological and economic feasibility for U.S. Steel, DIG, 
Cleveland-Cliffs, and EES Coke.
    Response: Section 172 (c)(1) of the CAA provides that ``such plan 
shall provide for the implementation of all reasonably available 
control measures as expeditiously as practicable (including such 
reductions in emissions from existing sources in the area as may be 
obtained through the adoption, at a minimum, of reasonably available 
control technology) and shall provide for attainment of the national 
primary ambient air quality standards.'' EPA has long defined RACT for 
SO2 as that control technology which will achieve the NAAQS 
within statutory timeframes. See State Implementation Plans; General 
Preamble for the Implementation of Title I of the Clean Air Act 
Amendments of 1990; Proposed Rule, 57 FR 13498, 13547 (April 16, 1992) 
(General Preamble); see also, SO2 Guideline Document, U.S. 
Environmental Protection Agency, Office of Air Quality Planning and 
Standards, Research Triangle Park, NC 27711, EPA-452/R-94-008, February 
1994 (SO2 Guideline), at 6-39. For most criteria pollutants, 
RACT is control technology that is reasonably available considering 
technological and economic feasibility. The definition of RACT for 
SO2 is that control technology which is necessary to achieve 
the NAAQS (40 CFR 51.100(o)). Since SO2 RACT is already 
defined as the technology necessary to achieve the SO2 
NAAQS, control technology which failed to achieve the NAAQS would fail 
to be SO2 RACT. EPA intends to continue defining RACT for 
SO2 as that control technology which will achieve the NAAQS, 
as it has in numerous SIP actions since promulgating the 2010 NAAQS. 
Here, the emission limits in the FIP and previously approved into the 
SIP provide for such NAAQS attainment, as demonstrated by the modeling. 
Consequently, under EPA's longstanding approach to SO2 RACT, 
the CAA section 172(c)(1) RACM/RACT requirement is met. CAA section 
172(c)(6) also requires plans to include enforceable emission limits 
and control measures as may be necessary or appropriate to provide for 
attainment. The emission limits and associated requirements included as 
part of the FIP analysis show attainment of the 2010 SO2 
NAAQS of 75 ppb, as the modeling analysis, which is detailed in the 
technical support document for this action, shows a maximum 
concentration of 73.6 ppb. Thus, further controls are not necessary to 
satisfy the requirement for RACT.\6\
---------------------------------------------------------------------------

    \6\ See SO2 Guideline Document, U.S. Environmental 
Protection Agency, Office of Air Quality Planning and Standards, 
Research Triangle Park, N.C. 27711, EPA-452/R-94-008, February 1994. 
See also EPA's 2014 SO2 Nonattainment Guidance; General 
Preamble for the Implementation of Title I of the Clean Air Act 
Amendments of 1990 at 57 FR 13498 (April 16, 1992).
---------------------------------------------------------------------------

    As determined through air dispersion modeling, emission limits and 
associated requirements at the U.S. Steel, EES Coke, DIG, Cleveland-
Cliffs Steel Corporation, DTE Trenton

[[Page 61521]]

Channel, and Carmeuse Lime facilities are needed to reach attainment in 
the Detroit area. While EPA recognizes the commenters' concern that the 
annual maximum emissions allowed under the U.S. Steel limits set forth 
in the FIP are larger than actual emissions in previous years, EPA 
believes that setting limits at U.S. Steel, a facility that has not 
previously had hourly SO2 emission limits, is critically 
important to ensuring that SO2 concentrations in the Detroit 
area stay permanently below the NAAQS.
    Comment: The commenters point out that the FIP does not require 
monitoring, recordkeeping, or reporting from U.S. Steel No. 2 Baghouse 
or DIG Flares 1 and 2.
    Response: EPA notes that U.S. Steel No. 2 Baghouse was mistakenly 
omitted from 40 CFR 52.1189(b)(3)(ii) in the proposed regulatory text 
and EPA has updated 40 CFR 52.1189(b)(3)(ii) to include U.S. Steel No. 
2 Baghouse. Recordkeeping and reporting for U.S. Steel No. 2 Baghouse 
are required under 40 CFR 52.1189(b)(5)(ii) and 40 CFR 
52.1189(b)(6)(ii), respectively. Regarding compliance for DIG Flares 1 
and 2, EPA has added the requirement to 40 CFR 52.1189(e)(2) that the 
owner or operator verify compliance with the limit for Boilers 1, 2, 3 
and Flares 1 and 2 (combined) by following the procedures and 
methodologies contained in the document entitled ``Protocol for 
Demonstrating Continuous Compliance with the Emission Limitations of 
ROP MI-ROP-N6631-2004'' as set forth in its operating permit (Permit 
MI-ROP-N6631-2012a, modified June 28, 2016).
    Comment: EPA received seven comments regarding emissions monitoring 
requirements. The commenters believe that the FIP should require all 
units, particularly at U.S. Steel and DIG, to install a Continuous 
Emission Monitoring System (CEMS) on all units to monitor 
SO2 emissions directly, which the commenters state would be 
a much more accurate and transparent way to monitor emissions than what 
the proposed FIP requires. The commenters state that it is unclear as 
to why the FIP would require CEMS to be installed at U.S. Steel 
Boilerhouse 2 but not at U.S. Steel Boilerhouse 1 and why the FIP would 
require CEMS for the Cleveland-Cliffs Steel Corporation blast furnaces 
but not the U.S. Steel blast furnaces. The commenters also state that 
it is unclear as to why a Predictive Emissions Monitoring System (PEMS) 
is allowed in lieu of CEMS to monitor DIG emissions. A commenter states 
that CEMS are available and commonly used and that it is particularly 
important that SO2 emissions are monitored closely as the 
maximum modeled SO2 concentration is very close to the 
NAAQS. The commenters recommend that EPA require CEMS to be installed 
at each U.S. Steel and DIG unit, and that EPA explain the choice of 
monitoring technique if CEMS is not deemed appropriate, considering 
regulatory needs, monitoring technology costs, and relative benefits of 
the monitoring technique.
    Response: With regard to DIG units, the FIP requires compliance as 
set forth in its operating permit (Permit MI-ROP-N6631-2012a, modified 
June 28, 2016). As described in the response above regarding DIG Flares 
1 and 2 compliance, EPA added additional compliance language to 40 CFR 
52.1189(e)(2). These compliance mechanisms are currently in place and 
work to sufficiently monitor hourly SO2 emissions at the DIG 
facility; therefore, EPA is not requiring CEMS on the DIG units at this 
time.
    With regard to U.S. Steel units, the FIP requires CEMS on 
Boilerhouse 2, the highest-emitting unit at the facility, as part of 
the new stack construction. For the remaining U.S. Steel units, the FIP 
requires the owner or operator to calculate hourly SO2 
emissions using all raw material sulfur charged into each affected 
emission unit and assumes 100 percent conversion of total sulfur to 
SO2 to be conservative. Aside from the U.S. Steel 
boilerhouses, blast furnaces, and the associated furnace flares, the 
other emission limits for other U.S. Steel units are very small (all 
less than 5 pounds per hour (lbs/hr) and only one over 1 lbs/hr). Many 
large SO2 sources, such as blast furnace stoves, blast 
furnace flares, and (reheat) furnaces, combust blast furnace gas and/or 
coke oven gas. These gases are considered fuel for those units. EPA 
believes that frequent fuel sampling will provide sufficiently accurate 
measurement of SO2 emissions. Fuel sampling has historically 
been used to determine emissions, and EPA believes this method is 
acceptable here. The FIP requires the owner or operator of each 
applicable U.S. Steel unit to submit a Compliance Assurance Plan (CAP) 
for the unit that specifies calculation methodology, procedures, and 
inputs used in these calculations. EPA expects that the procedures 
shall include a fuel sampling schedule at a frequency that captures any 
variation in fuel sulfur content. Additionally, while Boilerhouse 1 is 
not currently operating, U.S. Steel has committed not to combust coke 
oven gas at Boilerhouse 1 upon restart, which is reflected in the 
Boilerhouse 1 limit set forth in the FIP. EPA concludes that the 
required CAPs, as well as the quarterly requirement to submit 
calculated hourly SO2 emissions to EPA, are sufficient for 
determining compliance with the emission limits set forth in the FIP. 
However, the requirement of CAPs does not preclude future requirements 
or installation of CEMS on these units.
    Comment: The commenters believe that the requirement that U.S. 
Steel submit a CAP for units that do not require CEMS detailing the 
calculation methodology, procedures, and inputs that will be used for 
monitoring SO2 emissions is insufficient. The commenters 
believe that U.S. Steel's CAPs should undergo public notice and 
comment, but point out that this is not possible as the plans are 
required to be submitted after the effective date of the FIP. 
Additionally, the commenters pointed out that the FIP does not allow 
EPA the authority to review, modify, or reject a CAP, and that the CAP 
does not require continuous monitoring.
    Response: EPA disagrees with the commenters' position that the 
requirement for U.S. Steel to submit CAPs is insufficient. The public 
is not an approving authority for CAPs, and therefore, there is no 
requirement that the owner or operator submit the CAPs for public 
review and approval. However, for transparency and ease in 
accessibility, EPA will post the CAPs to the Detroit SO2 FIP 
website at https://www.epa.gov/mi/detroit-so2-federal-implementation-plan. Although the FIP does not require EPA's explicit approval of 
CAPs, EPA has authority to enforce the requirement to submit CAPs that 
meet the requirements set forth in the FIP. Failure to submit a CAP or 
submission of a CAP that does not meet the requirements set forth in 
the FIP would be a violation of the FIP. The owner or operator of the 
U.S. Steel facility is required to maintain records of hourly emissions 
calculated in accordance with the CAP under 40 CFR 52.1189(b)(5)(ii) 
and to report these hourly mass balance calculations, as well as excess 
emissions, quarterly, and no later than the 30th day following each 
quarter under 40 CFR 52.1189(b)(6)(ii) and 40 CFR 52.1189(b)(6)(iv), 
respectively.
    Comment: EPA received three comments about idled units at U.S. 
Steel. The commenters contend that although the FIP requires that a CAP 
be submitted for each idled U.S. Steel unit under 40 CFR 52.1189(b)(4), 
the FIP does not require U.S. Steel to comply with emission limits or 
monitoring requirements for idled units. One commenter states that the 
community is very concerned with the reopening of

[[Page 61522]]

U.S. Steel and believes the FIP should include limits for idled units.
    Response: The FIP includes limits for all units, regardless of 
operating status. The idled units referenced in 40 CFR 52.1189(b)(4) 
each have limits under 40 CFR 52.1189(b)(1)(i). Additionally, emissions 
from these units are required to be monitored and reported under 40 CFR 
52.1189(b)(3)(ii) and 40 CFR 52.1189(b)(6)(ii), respectively.
    Comment: EPA received three comments about contingency measures in 
the FIP. The commenters disagree with EPA's interpretation of 
contingency measures for SO2 to mean that the State, or EPA 
in the case of a FIP, has a comprehensive enforcement program. The 
commenters suggest that under CAA section 172(c)(9), contingency 
measures must take effect without further action by the State or EPA, 
which would exclude enforcement actions because an enforcement action 
is further action. Additionally, the commenters state that enforcement 
actions are not ``measures'' as defined in CAA section 110(a)(2), and 
that a comprehensive enforcement program is already required separately 
under CAA section 110(a)(2). The commenters also note that enforcement 
actions are not reviewable under the Administrative Procedure Act 
(APA), so citizens are not able to enforce EPA's proposed contingency 
measures, and that EPA's reliance on enforcement actions is contrary to 
the history of the CAA due to their discretionary nature.
    Additionally, the commenters allege that authority to enforce the 
FIP does not equate to a comprehensive enforcement program, which the 
commenters suggest would mean having a schedule for determining whether 
violations occurred and a binding mechanism requiring EPA to take 
action if they did occur. The commenters suggest that a comprehensive 
enforcement program could not be called aggressive unless it went 
beyond the basic enforcement requirements, for example, increasing the 
basic mandatory penalty scheme.
    The commenters also point out that contingency measures are 
intended to address situations that cause an area to fail to attain 
despite a valid attainment demonstration and that there is no specific 
measure in the proposed FIP that would be activated in the case that 
EPA's analysis that the FIP will bring the Detroit area into attainment 
is incorrect. The commenters contend that it is more likely that 
violations of the 1-hour standard will occur with longer-term average 
limits in the FIP due to short-term spikes in emissions at sources that 
are still complying with their long-term average limits. The commenters 
state that the fact that EPA does not require a new SIP submittal for 
determining whether an area has attained the standard, even though 
modeling parameters such as source characteristics and background 
concentrations could have changed, is an additional issue if 
contingency measures do not address failures to attain despite valid 
attainment demonstrations.
    The commenters state that EPA failed to include contingency 
measures in the FIP regulatory text and recommend that EPA incorporate 
alternative contingency measures into the FIP, such as switching to 
low-sulfur fuel, limiting operation until the SIP is revised, limits 
that automatically scale to adjust for background concentrations, and 
supplementary short-term limits for longer-term average limits. The 
commenters state that these suggested contingency measures could be 
promulgated as rules to take effect without further action from EPA. 
The commenters disagree that the contingency measures language as 
written in CAA section 172(c)(9) does not apply to SO2 plans 
and was directed at other pollutants such as ozone, as Congress added 
specific contingency measures language in the ozone provisions but did 
not change the general contingency measures provisions in CAA section 
172(c)(9). The commenters argue that without implementing alternative 
contingency measures, EPA fails to make a good-faith effort to comply 
with the terms of the September 30, 2020, consent decree to promulgate 
a FIP that complies with the CAA.
    Response: EPA disagrees with the commenter that the contingency 
measures are inadequate. Section 172(c)(9) of the CAA defines 
contingency measures as such measures in a nonattainment plan that are 
to be implemented in the event that an area fails to make RFP, or fails 
to attain the NAAQS, by the applicable attainment date. Contingency 
measures are to become effective without further action by the State or 
EPA, where the area has failed to (1) achieve RFP or, (2) attain the 
NAAQS by the statutory attainment date for the affected area. These 
control measures are to consist of other available control measures 
that are not included in the control strategy for the attainment plan 
SIP for the affected area.
    However, EPA has long interpreted the contingency measures 
requirement for SO2 in light of the fact that SO2 
presents special considerations. See, General Preamble at 13547; see 
also, SO2 Guideline at 6-40--6-41, 2014 Guidance at 41-42. 
EPA interprets the contingency measure provisions as primarily directed 
at NAAQS implementation which can be undertaken on an areawide basis, 
such as for ozone or particulate matter. EPA's policy for 
SO2 is different because, first, for some of the other 
criteria pollutants, the analytical tools for quantifying the 
relationship between reductions in precursor emissions and resulting 
air quality improvements remain subject to significant uncertainties, 
in contrast with procedures for directly-emitted pollutants such as 
SO2. Second, emissions estimates and attainment analyses for 
other criteria pollutants can be strongly influenced by overly 
optimistic assumptions about control efficiency and rates of compliance 
for many small sources. This is not the case for SO2.
    In contrast, the control efficiencies for SO2 control 
measures are well understood and are far less prone to uncertainty. 
Since SO2 control measures are by definition based on what 
is directly and quantifiably necessary to attain the SO2 
NAAQS, it would be unlikely for an area to implement the necessary 
emission controls yet fail to attain the NAAQS. Therefore, for 
SO2 programs, EPA has long explained that ``contingency 
measures'' can mean that the air agency has a comprehensive program to 
identify sources of violations of the SO2 NAAQS and to 
undertake an aggressive follow-up for compliance and enforcement, 
including expedited procedures for establishing enforceable consent 
agreements pending the adoption of a revised SIP. EPA believes that 
this approach continues to be valid for the implementation of 
contingency measures to address the 2010 SO2 NAAQS, and 
consequently reiterated its view in the preamble to the final 2010 
NAAQS and has followed it in several actions on SIPs implementing the 
2010 NAAQS. See, e.g., Primary National Ambient Air Quality Standard 
for Sulfur Dioxide; Final Rule, 75 FR 35520, 35576 (June 22, 2010); 
Approval and Promulgation of Air Quality Implementation Plans; 
Pennsylvania; Attainment Plan for the Warren County, Pennsylvania 
Nonattainment Area for the 2010 Sulfur Dioxide Primary National Ambient 
Air Quality Standard; Final Rule, 83 FR 51629, 51632-33; Approval and 
Promulgation of Air Quality Implementation Plans; Pennsylvania; 
Attainment Plan for the Beaver, Pennsylvania Nonattainment Area for the 
2010 Sulfur Dioxide Primary National Ambient Air Quality Standard; 
Final Rule, 84 FR 51988,

[[Page 61523]]

51994-95. EPA therefore concludes that EPA's comprehensive enforcement 
program, as discussed below, satisfies the SO2 contingency 
measure requirement.
    The commenters listed several options for specific contingency 
measures. EPA acknowledges that one or more of these options may be 
appropriate in a specific situation, and for a specific source, if the 
area fails to achieve RFP or fails to attain the NAAQS by the statutory 
attainment date. However, in this situation, as Detroit is a 
multisource area with several emission units per facility, requiring 
one or more of these measures also may not be appropriate depending on 
the cause of the potential violation, which would need to be evaluated 
at the time of occurrence. For example, triggering a fuel-switch at one 
facility may not bring the area into attainment if the issue is caused 
by another facility violating its limit. Similarly, limiting operation 
of one facility may be appropriate if EPA determines that the subject 
facility is the cause of the problem, but requiring additional measures 
at other facilities may not be warranted where the cause of the NAAQS 
violation was non-compliance by a different facility and where the 
NAAQS violation can be most efficiently remedied by bringing that 
source into compliance with its established emission limits. Likewise, 
limiting operations at all SO2 facilities in the area may 
not appropriately address the issue due to the localized nature of 
SO2 emissions and direct link to a specific facility. 
Changing the limits at all facilities from a longer-term limit to a 
shorter-term limit similarly may appropriately address the problem, but 
this action also may not, and EPA would evaluate appropriate measures 
if and when an issue arises. These are illustrative examples, and while 
not exhaustive, highlight the need for EPA to be able to respond 
appropriately in a particular scenario due to the localized nature of 
SO2 impacts. In any case where the Detroit area fails to 
achieve RFP or attain the NAAQS, EPA would consider all viable 
solutions to address the actual issue at a specific facility or 
facilities and take appropriate responsive action.
    In accordance with longstanding policy, EPA deems investigation and 
enforcement authority for aggressive follow-up for ensuring source 
compliance an appropriate and expeditious solution to any potential 
violations.
    As noted in the proposed rule, EPA's 2014 SO2 guidance 
describes special features of SO2 planning that influence 
the suitability of alternative means of addressing the requirement in 
CAA section 172(c)(9) for contingency measures including a 
comprehensive enforcement program. EPA has a comprehensive enforcement 
program as specified in section 113(a) of the CAA. Under this program, 
EPA is authorized to take enforcement actions to ensure compliance with 
the CAA and the rules and regulations promulgated under the CAA. Such 
actions include the issuance of an administrative order requiring 
compliance with the applicable implementation plan; the issuance of an 
administrative order requiring the payment of a civil penalty for past 
violations; and the commencement of a civil judicial action. Orders 
issued under CAA section 113(a) require subject entities to comply with 
the requirements set forth in the order as expeditiously as 
practicable, but in no event longer than one year after the date the 
order was issued. Issuance of any such order does not prohibit EPA from 
assessing any penalties. Under CAA section 113(b), civil judicial 
enforcement may require assessment of penalties of up to $109,024 per 
day for each violation.\7\ Additionally, under CAA section 113(c), any 
person who knowingly violates any requirement or prohibition of an 
implementation plan may be subject to criminal enforcement, with 
penalties including fines and imprisonment.
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    \7\ Pursuant to the Civil Monetary Penalty Adjustment Rule, 87 
FR 1676 (Jan. 12, 2022), codified at 40 CFR 19.4.
---------------------------------------------------------------------------

    EPA's enforcement program is capable of prompt action to remedy 
compliance issues. Additionally, enforcement in communities with 
environmental justice concerns is a priority for EPA. EPA's steps to 
advance environmental justice through enforcement include increasing 
the number of facility inspections in overburdened communities, 
resolving noncompliance through remedies with tangible benefits, and 
increasing engagement with communities about enforcement cases that 
most directly impact them.\8\ EPA also notes that under CAA section 
304, citizens may also commence civil enforcement actions against any 
person who is in violation of an emission standard. See 42 U.S.C. 
7604(a)(1), (f). Therefore, EPA believes that EPA's enforcement program 
by itself suffices to meet CAA section 172(c)(9) requirements for 
SO2 as interpreted in the 1992 General Preamble, the 
SO2 Guideline, the 2010 SO2 NAAQS promulgation, 
the 2014 SO2 guidance, and in numerous subsequent SIP 
actions. Finally, EPA disagrees with the assertion that without 
implementing alternative contingency measures, EPA fails to make a 
good-faith effort to comply with the terms of the September 30, 2020, 
consent decree to take final action to promulgate a FIP. The consent 
decree properly imposes only a September 30, 2022, deadline for EPA to 
sign a notice of final rulemaking to approve a revised SIP submission, 
to promulgate a FIP, or to approve in part a revised SIP submission and 
promulgate a partial FIP for the Detroit area addressing the elements 
of CAA sections 172(c) and 192, but does not (as it could not) impose 
any requirements for how EPA might meet the statutory elements.
---------------------------------------------------------------------------

    \8\ See https://www.epa.gov/sites/default/files/2021-04/documents/strengtheningenforcementincommunitieswithejconcerns.pdf.
---------------------------------------------------------------------------

    Comment: EPA received eight comments about environmental justice. 
The commenters contend that while EPA recognized that communities are 
located in the Detroit nonattainment area with environmental justice 
concerns, EPA did not conduct a meaningful analysis or adequately use 
its discretionary authority to consider environmental justice in 
development of the FIP. The commenters state that EPA did not follow 
Executive Order 12898, which directs EPA to achieve environmental 
justice to the greatest extent practicable and permitted by law. The 
commenters contend that EPA should have considered alternatives to its 
proposed plan and how the FIP could provide the most benefit to Detroit 
populations given the history of industrial pollution and nonattainment 
for multiple pollutants and the environmental justice communities in 
the Detroit nonattainment area, which are demonstrated by EPA's 
EJScreen as well as other screening tools such as the draft Climate and 
Economic Justice Screening Tool and the Michigan EJ screen map. The 
commenters also believe that EPA should consider actions that can be 
taken to acknowledge and address the impacts of the delay in bringing 
the Detroit area into attainment, and ensure that any future 
nonattainment is addressed promptly, as well as more fully acknowledge 
the burden that Detroit community members of different populations have 
faced due to nonattainment. One commenter points out that EPA's 
conclusion that the FIP will decrease pollution levels, which will be 
beneficial to the environmental justice populations in Detroit, does 
not address the fact that it will not be more beneficial to 
environmental justice populations than others in the area nor 
acknowledge the harm that previous emissions in the area have caused 
the

[[Page 61524]]

community. The commenters believe that EPA only took steps to 
promulgate a FIP as a result of a consent decree arising from a 2021 
civil action, as EPA's deadline to promulgate a FIP was April 18, 2018, 
so the commenters request that EPA explain the delay in promulgating a 
FIP.
    The commenters recommend that EPA's environmental justice analysis 
address the presence of vulnerable populations in the nonattainment 
area and include an analysis of the FIP's impact on these vulnerable 
populations, such as individuals with asthma, particularly with respect 
to long-term average emission limits. The commenters note that the 
presence of asthma in Detroit is extremely high as compared to the rest 
of the state and point to studies showing that vulnerable populations 
may experience health effects associated with SO2 
concentrations below the NAAQS. The commenters state that affected 
populations of the nonattainment area need assurance on plans for 
access to healthcare, asthma treatment, and air filtration. The 
commenters also request a more detailed description of aggressive 
enforcement measures EPA will use and recommend that EPA require all 
sources to install CEMS.
    Response: While EPA appreciates the commenters' concerns and the 
issues facing communities in the greater Detroit area, in general EPA 
disagrees with the commenters' characterization of EPA's consideration 
of environmental justice as it regards this action. EPA is aware of the 
demographic data for the Detroit nonattainment area, and that the 
Detroit nonattainment area includes communities that are pollution-
burdened and underserved. In part for this reason, EPA conducted 
outreach beyond its obligations of notice-and-comment rulemaking as 
discussed in the response to comments on EPA's outreach and comment 
process below.
    Under section 109 of the CAA, EPA sets primary, or health-based, 
NAAQS for all criteria pollutants to provide requisite protection of 
public health, including the health of at-risk populations, with an 
adequate margin of safety. In EPA's June 22, 2010, rulemaking 
strengthening the SO2 NAAQS to the level of 75 ppb, EPA 
provided a detailed rationale for the Administrator's determination 
that the 2010 SO2 NAAQS would be protective of public health 
(75 FR 35520). This rationale included explicit consideration of 
protection for people, including children, with asthma. Specifically, 
the standard was based on direct evidence of SO2-related 
effects in controlled human exposure studies of exercising individuals 
with asthma, as well as epidemiologic evidence of associations between 
SO2 concentrations in ambient air and respiratory-related 
emergency department visits and hospitalizations.
    Commenters reference Executive Order 12898 (59 FR 7629, February 
16, 1994), which directs Federal agencies, to the greatest extent 
practicable and permitted by law, to identify and address 
disproportionately high and adverse human health or environmental 
effects of their actions on minority and low-income populations. 
Executive Order 12898 is addressed in the executive order section of 
this action. With regard to environmental justice considerations, to 
identify environmental burdens and susceptible populations in 
communities in the Detroit nonattainment area, EPA performed a 
screening-level analysis using EPA's EJ screening and mapping tool 
(``EJScreen'').\9\ EPA prepared two EJScreen reports covering buffer 
areas of 1- and 6-mile diameters around U.S. Steel, which is the main 
facility impacted by the FIP. Our screening-level analysis of the area 
strongly suggests that communities within the selected buffer areas 
bear a high overall pollution burden as indicated by high percentile 
values for particulate matter and other environmental indicators, as 
well as high percentiles of low income and people of color. 
Specifically, the 6-mile buffer included in the docket of this 
rulemaking showed that the percentage of low-income individuals is 
almost twice the U.S. average. These results highlight commenters' 
concerns of the pollution burdens that Detroit community members of 
different populations have faced.
---------------------------------------------------------------------------

    \9\ See documentation on EPA's Environmental Justice Screening 
and Mapping Tool at https://www.epa.gov/ejscreen.
---------------------------------------------------------------------------

    Considering these results, EPA further considered emission 
reductions expected from the FIP and forthcoming emission reduction 
measures that may help to mitigate existing pollution issues in the 
area. As explained in the proposal, the proposed FIP regulatory 
language includes new SO2 emission limits throughout the 
U.S. Steel facility. Additionally, the FIP includes several new 
requirements for U.S. Steel's Boilerhouse 2, including the requirement 
to combine and raise its stacks to increase dispersion away from the 
area, new limits, and installation of a new CEMS. Further, EPA included 
the DTE Trenton Channel permit as part of the FIP analysis, which was 
scheduled to retire 10 11 at the time the proposed FIP was 
published and has since shut down as of June 19, 2022. Hence, the FIP 
analysis included the permitted (Permit to Install 125-11C) enforceable 
SO2 limit of 5,907 lbs/hr on a 30-day average basis 
applicable to DTE Trenton Channel as a precautionary measure. Actual 
emissions at DTE Trenton Channel in recent years were 3,114, 3,754, and 
885 tons per year (tpy) in 2018, 2019 and 2020, respectively. In Wayne 
County (the partial county containing in the Detroit SO2 
Nonattainment area), these reductions would account for 25.2, 31.9 and 
14.8 percent of SO2 emissions in 2018, 2019 and 2020, 
respectively. While EPA recognizes the importance of assessing impacts 
of our actions on potentially overburdened communities, we believe that 
the promulgation of the FIP will not adversely affect disproportionally 
impacted populations in the Detroit nonattainment area. The purpose of 
the FIP is to ensure attainment and maintenance of the NAAQS, so 
promulgation of this FIP is expected to have a positive impact on the 
Detroit nonattainment area as a whole, for all populations in the 
Detroit nonattainment area.
---------------------------------------------------------------------------

    \10\ See https://earthjustice.org/news/press/2022/coal-plants-retiring-with-millions-of-dollars-flowing-to-environmental-justice-communities.
    \11\ See https://earthjustice.org/sites/default/files/files/267-1_-_sierra_club_-_dte_separate_agreement.pdf.
---------------------------------------------------------------------------

    With regard to the delay in bringing the area into attainment, 
Michigan and EPA have faced several obstacles during the attainment 
planning process, beginning with the invalidation of Michigan 
Administrative Code (MAC) 336.1430 (``Rule 430'') by the Michigan Court 
of Claims on October 4, 2017. The court held that, because Rule 430 
contained enforceable limits for U.S. Steel and the limits applied to a 
single facility, Rule 430 failed the ``general applicability'' 
requirement of Michigan's Administrative Procedures Act, Michigan 
Compiled Laws (MCL) 24.201 et seq. The court expressly declined to 
advise how the State could properly impose emission limits on the 
source at issue via other means but noted elsewhere in the decision 
that the state and other sources ``agreed to revise pertinent DEQ 
permits.'' Since the time of the designation, Michigan and EPA have 
been working on an approvable attainment plan and emission reductions 
in the area. In addition, to the extent that the State prefers to 
proceed via generally applicable state regulations rather than permits, 
EPA expects that Michigan will draft future rules to avoid the concerns 
raised by the

[[Page 61525]]

court which resulted in invalid SO2 limits to avoid this 
issue going forward.
    In 2016, Michigan submitted an SO2 attainment plan for 
the Detroit nonattainment area, which included limits for DTE Trenton 
Channel, DTE River Rouge, Carmeuse Lime, and U.S. Steel. While EPA was 
unable to approve the 2016 attainment plan as a whole, EPA did approve 
the limits for DTE Trenton Channel and Carmeuse Lime into Michigan's 
SIP on March 19, 2021. The compliance dates for DTE Trenton Channel and 
Carmeuse Lime permits were January 1, 2017, and October 1, 2018, 
respectively, and both facilities have been in compliance since their 
respective dates. In March 2020, a more stringent interim limit for DTE 
River Rouge became effective, and in May 2021 the facility shut down.
    Although the FIP is based on maximum allowable or uncontrolled 
emissions, EPA also completed a model run using actual emissions from 
2015-2017, which was used in EPA's January 28, 2022, action to 
determine whether the area attained the standard by the attainment date 
(87 FR 4501). The modeling was based on guidelines from appendix W of 
40 CFR part 51 and EPA's TAD that contained an assessment of the air 
quality impacts from the following sources: U.S. Steel Ecorse, U.S. 
Steel Zug Island, EES Coke, DTE River Rouge, DTE Trenton Channel, 
Carmeuse Lime, DTE Monroe, Cleveland-Cliffs Steel Corporation, DIG, and 
Marathon Refinery. The modeling demonstration included actual emissions 
for DTE River Rouge, Trenton Channel, and U.S. Steel, the source that 
was determined to have the most significant contribution to the maximum 
NAAQS violations in the area. EPA found that the areas with modeled 
SO2 concentrations above the NAAQS were on and surrounding 
Zug Island in areas that are not residential, while all the monitors in 
the Detroit nonattainment area showed values below the NAAQS. The 
updated FIP analysis modeled attainment of the NAAQS in the Detroit 
nonattainment area after inclusion of the new U.S. Steel emission 
limits proposed in this FIP and the emission reduction measures that 
have already occurred since the finding of failure to attain, including 
the previously approved DTE Trenton Channel and Carmeuse Lime emission 
limits and the shutdown of DTE River Rouge. The implementation of the 
FIP makes these reductions, as well as the existing emission limits at 
EES Coke, Cleveland-Cliffs Steel Corporation, and DIG, permanent and 
enforceable and provides protection for future attainment. Further, as 
previously discussed, these reductions will be even greater with the 
shutdown of DTE Trenton Channel.
    With regard to the enforcement measures that EPA will use, as 
stated in the proposed rule, options include the issuance of an 
administrative order requiring compliance with the applicable 
implementation plan; the issuance of an administrative order requiring 
the payment of a civil penalty for past violations; and the 
commencement of a civil judicial action. These options are explained 
further in the response to the comment above regarding contingency 
measures. While the FIP does not require CEMS on all units, as 
explained in the response to comments about CEMS above, EPA is 
confident that the FIP provides adequate means of determining whether a 
violation has occurred in order to take appropriate enforcement action.
    Comment: EPA received four comments on EPA's outreach and comment 
process. The commenters contend that the timeline between the proposed 
rule publication date and the public hearing and public hearing 
registration deadline was not sufficient and should have been closer to 
30 or 45 days, similar to other EPA comment periods. The commenters 
state that while EPA is facing a tight deadline to finalize the FIP, 
the tight timeline is due, in part, to EPA's delay in responding to 
Michigan's SIP.
    The commenters also state that while EPA held a meeting with 
various Detroit environmental organizations and community groups in 
March 2022, the FIP was not the main focus of the meeting and a more 
robust approach to community outreach was needed, particularly due to 
the high levels of limited English proficiency (LEP) persons living in 
the area. The commenters give examples of ways that EPA could have 
improved its public outreach, including holding a community meeting 
before the proposed FIP was published, working with community groups in 
the area to distribute information, and providing handouts about the 
FIP surrounding the public hearing. One commenter believes that EPA 
should engage with the public as soon as new NAAQS are set and EPA 
knows which areas area likely to fall into nonattainment about the 
causes and impacts of the nonattainment designation and solutions being 
sought, as well as after each delay to explain why the delay occurred 
and how it will be avoided in the future.
    Additionally, the commenters state that EPA only provided notice of 
the hearing in the proposed rule published in the Federal Register and 
did not provide notice that was sufficiently accessible on widely 
disseminated platforms or reach out directly to the community. In 
particular, the commenters note that the proposed rule was published in 
English with no translation services available and that translation 
services were not made available for the public hearing, which is of 
particular concern due to the Spanish and Arabic speaking communities 
in and surrounding the nonattainment area. The commenters note that 
while EPA did solicit requests for translation services in the proposed 
rule, this solicitation did not give LEP persons meaningful access to 
translation services as it was published in an English-only document 
with a tight deadline for submitting requests. Therefore, the 
commenters suggest that EPA should have proactively provided Arabic and 
Spanish translation services at the public hearing.
    The commenters contend that EPA did not meet its obligations under 
Executive Order 13166 and EPA's FY 2022-2026 Strategic Plan and has 
subjected individuals to discrimination by failing to proactively reach 
out to LEP persons in and around the nonattainment area due to the high 
percentages of LEP persons in the area, as shown in EJScreen analyses 
completed by both commenters and EPA. Additionally, the commenters 
mention the Informal Resolution Agreement that EPA entered with 
Michigan, under which Michigan developed an LEP Plan. The commenters 
believe that EPA should have followed the guidelines set forward in 
this plan, which include providing solicitations for translation 
services in other languages besides English and developing a strategy 
to best engage with LEP individuals. The commenters note that while EPA 
has since translated a fact sheet into Arabic and Spanish, these fact 
sheets were not available at the beginning of the comment period and 
EPA did not release a plan on how to ensure the documents would reach 
LEP persons.
    Response: EPA appreciates the commenters' suggestions on how EPA 
can improve its outreach and comment process and will consider, as 
appropriate, in future actions the suggestions to extend the time 
between proposal publication and public hearing, engage earlier with 
the public, and reach out to LEP communities before the comment period. 
However, EPA would like to highlight the additional outreach efforts 
that EPA made surrounding the FIP proposal publication beyond its 
obligations of notice-and-comment rulemaking.

[[Page 61526]]

    As the commenters note, EPA held a meeting with representatives 
from the City of Detroit, Michigan Environmental Council, Great Lakes 
Environmental Law Center (GLELC), Southwest Detroit Environmental 
Vision, and the Ecology Center regarding the FIP, including a 
presentation by EPA and a roundtable discussion with these 
stakeholders. EPA disagrees that the FIP was not the main topic of the 
meeting and has posted the presentation and attendance list to the 
docket for this action. Specifically, after outlining a summary of the 
FIP proposal, EPA requested feedback on structuring future engagement 
with stakeholders in Detroit.
    In addition to communicating directly with stakeholders, EPA issued 
a press release on the day the proposed FIP was published in the 
Federal Register.\12\ The press release noted that EPA would be 
accepting public comments on the proposed FIP. EPA also created a 
website for the FIP containing a summary of the rule, as well as 
information about how to register for the public hearing or submit 
written comments. The FIP was also highlighted on EPA's Region 5 web 
page.
---------------------------------------------------------------------------

    \12\ https://www.epa.gov/newsreleases/epa-opens-public-comment-period-proposed-federal-plan-reduce-sulfur-dioxide-air.
---------------------------------------------------------------------------

    With regard to translation services for the public hearing, EPA 
solicited requests in both the Federal Register document as well as on 
the registration web page for the public hearing. EPA proactively 
arranged for interpretation services to be available at the public 
hearing in case the services were requested by registered attendees; 
however, no registered attendees requested these services or any other 
translation services.
    During the public comment period, EPA received a request from GLELC 
to delay the public hearing, as GLELC stated that EPA had not provided 
adequate outreach to LEP communities. Per the email exchange posted in 
the docket for this action, EPA was unable to delay the public hearing, 
but did what was possible during the comment period to address this 
request. As the commenters note, EPA created a fact sheet, which 
included information about how to submit written comments, during the 
comment period and translated it into Spanish and Arabic. EPA posted 
the fact sheets in the docket for this action, on the FIP web page, and 
on the general Spanish and Arabic EPA web pages. EPA appreciates the 
suggestions on how to reach out to LEP communities more proactively for 
future rulemakings.
    Comment: Two commenters argue that EPA should develop maps and 
other analyses that represent SO2 exposure within and 
outside of the nonattainment area in conjunction with maps illustrating 
cumulative impacts of social, economic, and physical environmental 
factors to show how SO2 concentrations add to cumulative 
pollution impacts and to evaluate environmental justice concerns.
    Response: The focus of this action is to ensure attainment of the 
SO2 NAAQS within the nonattainment area. EPA has no 
information suggesting that SO2 concentrations outside of 
the nonattainment area boundary are above the SO2 NAAQS, and 
EPA does not believe that exposure maps within and beyond the 
nonattainment are pertinent to demonstrating how the control measures 
and emissions limits in the FIP provide for attainment of the 
SO2 NAAQS in the Detroit area.
    Comment: The FIP includes two separate limits for U.S. Steel 
Boilerhouse 2 based on two different operating scenarios. Two 
commenters note that the FIP incorrectly states that Boilerhouse 2 is 
the only U.S. Steel unit operating under the scenario in which 
Boilerhouse 2 has a limit of 750.00 lbs/hr. The commenters point out 
that the modeling analysis for this scenario includes operation of the 
U.S. Steel Ecorse sources, which include the Hot Strip Mill, No. 2 
Baghouse, Main Plant Boiler No. 8, and Main Plant Boiler No. 9, in 
addition to Boilerhouse 2.
    Response: EPA notes that the U.S. Steel Ecorse sources were 
included in the modeling analysis for the scenario in which Boilerhouse 
2 has a limit of 750 lbs/hr and were incorrectly excluded from the 
scenario in the proposed rule. EPA has updated 40 CFR 52.1189(b)(1)(ii) 
accordingly. The limits for the U.S. Steel Ecorse sources are shown in 
Table 1 below.

                    Table 1--U.S. Steel Ecorse Limits
------------------------------------------------------------------------
                                                           SO2 emission
                          Unit                            limit (lbs/hr)
 
------------------------------------------------------------------------
Hot Strip Mill--Slab Reheat Furnace 1...................            0.31
Hot Strip Mill--Slab Reheat Furnace 2...................            0.31
Hot Strip Mill--Slab Reheat Furnace 3...................            0.31
Hot Strip Mill--Slab Reheat Furnace 4...................            0.31
Hot Strip Mill--Slab Reheat Furnace 5...................            0.31
No. 2 Baghouse..........................................            3.30
Main Plant Boiler No. 8.................................            0.07
Main Plant Boiler No. 9.................................            0.07
------------------------------------------------------------------------

    Comment: The proposed FIP includes a requirement for the owner or 
operator of the U.S. Steel facility to combine and raise all five 
stacks from each corresponding boiler at U.S. Steel Boilerhouse 2 into 
a single larger stack. Two commenters state that all five Boilerhouse 2 
boilers are not currently in operation. The commenters request that 
only stacks from the operating boilers be required to be included in 
the combined stack in order to reduce capital, operating, and 
maintenance costs. The commenters assert that if a boiler begins 
operation at a later date, it can be included in the stack at that 
time.
    Response: EPA agrees that not requiring any idled boiler stacks to 
be added to the combined Boilerhouse 2 stack, so long as no 
SO2 is emitted from Boilerhouse 2 except from the new stack 
after the new stack construction is required to be completed, would not 
affect attainment of the NAAQS in the Detroit area. Therefore, EPA is 
not explicitly requiring that all Boilerhouse 2 boilers be added to the 
combined stack, and EPA has updated 40 CFR 52.1189(b)(2)(i) 
accordingly. As set forth in 40 CFR 52.1189(b)(2)(ii), beginning two 
years after the effective date of the FIP, no owner or operator shall 
emit SO2 from Boilerhouse 2, except from the stack point at 
least 170 feet above ground level.
    Comment: EPA received two comments about the U.S. Steel Boilerhouse 
2 stack construction timeline. The commenters contend that the two 
years allotted for construction of the stack is not sufficient, as 
construction cannot begin until Michigan issues the construction 
permit. The commenters state that at least 15 months are needed to 
procure materials and complete stack construction, which would leave 9 
months for Michigan to issue the permit. The commenters allege that the 
timeline is aggressive, given that the completion is dependent on 
Michigan acting quickly to issue the permit.
    Response: EPA disagrees that the U.S. Steel Boilerhouse 2 stack 
construction timeline is insufficient. The construction permit process 
was considered as part of this timeline. Michigan is aware of the 
construction timeline, and the construction permit for the Boilerhouse 
2 stack construction is a high priority for the State. Additionally, 
Michigan is statutorily required to process permit applications within 
240 days if public comment is required and 180 days if public comment 
is not required.\13\ This

[[Page 61527]]

comment did not provide any new information on the project timeline, so 
therefore, EPA is not extending the timeline for the Boilerhouse 2 
stack construction.
---------------------------------------------------------------------------

    \13\ See correspondence between EPA and Michigan included in the 
docket for this action.
---------------------------------------------------------------------------

    Comment: The commenter states that the community would like to know 
if they will be notified if facilities reopen, how they would be 
affected if facilities have ownership changes, what kind of assurance 
there is that Michigan will not permit new sources in the area, and 
EPA's future commitment to the Detroit area.
    Response: The focus of this action is to ensure attainment of the 
SO2 NAAQS in the Detroit area. The requirements of the FIP 
will continue to apply regardless of any facility ownership change. If 
there are changes to the Michigan SIP, which includes the emission 
limits and requirements set forth in the FIP, those changes will be 
subject to public notice and comment.
    Comment: The commenter requests that EPA explain how it will 
guarantee that the FIP will attain and maintain the SO2 
NAAQS in light of the June 30, 2022, West Virginia v. EPA Supreme Court 
ruling regarding EPA's ability to regulate carbon emissions.
    Response: The attainment planning requirements that the FIP 
addresses are set forth in the CAA, and the June 30, 2022, Supreme 
Court ruling does not affect this action. This action regulates 
SO2 emissions, which the CAA explicitly requires, and does 
not regulate carbon emissions as such or impose limits on greenhouse 
gas emissions.
    Comment: The commenter states that industry should be held 
accountable for the pollution that it emits, and that industry and 
government do not provide sufficiently transparent air quality data.
    Response: This nonattainment plan provides emission limits and 
requirements for facilities in the Detroit area and is protective of 
the SO2 NAAQS. A variety of air quality data sources are 
available for the Detroit area, including but not limited to design 
value reports,\14\ ECHO,\15\ and AirNow.\16\
---------------------------------------------------------------------------

    \14\ See https://www.epa.gov/air-trends/air-quality-design-
values#:~:text=A%20design%20value%20is%20a,50Exit%20Exit%20EPA%20webs
ite.
    \15\ See https://echo.epa.gov/resources/echo-data/about-the-data.
    \16\ See https://gispub.epa.gov/airnow.
---------------------------------------------------------------------------

    Comment: The commenter requests that EPA minimize the cost and time 
required to implement the FIP, as the commenter states that a facility 
that is not economically viable is less likely to comply with limits.
    Response: The FIP includes limits and associated requirements 
needed to meet the NAAQS in the Detroit area. Compliance with the 
requirements of the FIP is not optional and is not dependent on a 
facility's economic viability. As discussed further above in the 
response to comments regarding continency measures, EPA has a 
comprehensive enforcement program as specified in section 113 of the 
CAA. Under this program, EPA is authorized to take any action it deems 
necessary or proper for the effective enforcement of the CAA and the 
rules and regulations promulgated under the CAA, including the 
requirements set forth in the FIP.
    Comment: The commenter states that alleged deficiencies in the 
model cannot be addressed by assuming DTE Trenton Channel will be shut 
down, as there are several model receptors with concentrations that 
exceed 70 ppb.
    Response: EPA's FIP modeling analysis does not assume the shutdown 
of DTE Trenton Channel. Instead, the FIP analysis includes the 
permitted (Permit to Install 125-11C) enforceable SO2 limit 
of 5,907 lbs/hr on a 30-day average basis as a precautionary measure. 
As described above, particularly in the response to comments regarding 
background concentrations and dispersion coefficients, EPA concludes 
that its modeling analysis sufficiently demonstrates attainment of the 
SO2 NAAQS of 75 ppb, even assuming continued operation of 
DTE Trenton Channel (which will not in fact operate).
    Comment: The commenter points out that the emission rate used for 
DTE Trenton Channel in the model is higher than the emission rate 
specified in the proposed FIP (7,834 lbs/hr versus 7,661 lbs/hr).
    Response: EPA notes the discrepancy between the DTE Trenton Channel 
emission rates in the proposed FIP and in the model. As no other 
changes were made to the model, EPA did not remodel based on this error 
alone, since the error resulted in a more conservative design value. 
EPA believes that this discrepancy has minimal impact on the maximum 
modeled concentration, and as it results in an overestimate, it does 
not have any negative impact on human health.

III. What action is EPA taking?

    EPA is promulgating a FIP for attaining the 2010 SO2 
NAAQS for the Detroit area and for meeting other nonattainment area 
planning requirements. In accordance with section 172 of the CAA, this 
FIP includes an attainment demonstration for the Detroit area and 
addresses requirements for RFP, RACT/RACM, enforceable emission 
limitations and control measures, and contingency measures. EPA has 
previously concluded that Michigan has addressed the requirements for 
emissions inventories for the Detroit area and nonattainment area NSR.
    The FIP is based on the Carmeuse Lime emission limits specified in 
Permit to Install 193-14A, the DTE Trenton Channel emission limits 
specified in Permit to Install 125-11C, and the U.S. Steel, EES Coke, 
Cleveland-Cliffs Steel Corporation, and DIG emission limits specified 
in the regulatory language of this FIP. The Carmeuse Lime and DTE 
Trenton Channel permits have already been approved into Michigan's SIP 
that is incorporated into 40 CFR part 52, so EPA is not re-
incorporating them into 40 CFR part 52 here.
    EPA made changes to the regulatory text that was included in the 
proposed FIP under 40 CFR 52.1189 paragraphs (b)(1)(ii), (b)(2)(i), 
(b)(3)(ii), and (e)(2) due to public comments received. These changes 
include updating the list of sources that may operate under the 
scenario in which U.S. Steel Boilerhouse 2 has a limit of 750.00 lbs/hr 
to include U.S. Steel Ecorse sources, as included in EPA's modeling 
analysis; not explicitly requiring all Boilerhouse 2 boiler stacks to 
be merged and raised, so long as no SO2 is emitted except 
from the new stack beginning two years after the effective date of the 
FIP; adding U.S. Steel No. 2 Baghouse to the list of units subject to 
monitoring requirements, which previously was incorrectly omitted; and 
adding language regarding compliance for DIG Flares 1 and 2. 
Additionally, EPA corrected a citation error in the proposed regulatory 
text under CFR 52.1189(b)(3)(iii).
    This FIP satisfies EPA's duty to promulgate a FIP for the area 
under CAA section 110(c) that resulted from the previous finding of 
failure to submit. However, it does not affect the sanctions clock 
started under CAA section 179 resulting from EPA's partial disapproval 
of the prior SIP, which would be terminated by an EPA rulemaking 
approving a revised SIP. See 40 CFR 52.31.

IV. Statutory and Executive Order Reviews

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

    This action is exempt from review by the Office of Management and 
Budget (OMB), as it is not a rule of general applicability. This action 
specifically regulates four facilities in Detroit, Michigan.

[[Page 61528]]

B. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. 
Under the Paperwork Reduction Act, a ``collection of information'' is 
defined as a requirement for ``answers to . . . identical reporting or 
recordkeeping requirements imposed on ten or more persons . . .'' 44 
U.S.C. 3502(3)(A). Because the FIP applies to just four facilities, the 
Paperwork Reduction Act does not apply. See 5 CFR 1320(c).
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid Office of Management and Budget (OMB) control number. 
The OMB control numbers for our regulations in 40 CFR are listed in 40 
CFR part 9.

C. Regulatory Flexibility Act

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. This action 
adds additional controls to certain sources. None of these sources are 
owned by small entities, and therefore are not small entities.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. The action imposes no enforceable duty on any state, 
local or tribal governments or the private sector.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

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

    This action does not have tribal implications, as specified in 
Executive Order 13175. It will not have substantial direct effects on 
tribal governments. Thus, Executive Order 13175 does not apply to this 
action.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because EPA does not believe the environmental health or safety risks 
addressed by this action present a disproportionate risk to children. 
To the extent this action will limit SO2 emissions, the rule 
will have a beneficial effect on children's health by reducing air 
pollution.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not subject to Executive Order 13211 (66 FR 28355, 
May 22, 2001), because it is not a significant regulatory action under 
Executive Order 12866.

I. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards.

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

    EPA believes that this action does not have disproportionately high 
and adverse human health or environmental effects on minority 
populations, low-income populations and/or indigenous peoples, as 
specified in Executive Order 12898 (59 FR 7629, February 16, 1994).
    This final rule will improve local air quality by reducing 
SO2 emissions in a part of the Detroit metropolitan area 
that includes a higher proportion of minority and low-income 
populations compared to the State or US averages. Socioeconomic 
indicators such as low income, unemployment rate and percentage of 
people of color \17\ were all at levels at least two times that of the 
state-wide averages (in some cases two to five times higher), within 
one to six miles from facilities affected by this action (see EJScreen 
analyses provided in the docket for this action). These populations, as 
well as all affected populations in this area, will stand to benefit 
from the increased level of environmental protection with the 
implementation of this rule.
---------------------------------------------------------------------------

    \17\ See https://www.epa.gov/ejscreen/overview-demographic-indicators-ejscreen for the definition of each demographic 
indicator.
---------------------------------------------------------------------------

K. Determination Under Section 307(d)

    Pursuant to CAA section 307(d)(1)(B), this action is subject to the 
requirements of CAA section 307(d), as it promulgates a FIP under CAA 
section 110(c).

L. Congressional Review Act (CRA)

    This rule is exempt from the CRA because it is a rule of particular 
applicability.

M. Judicial Review

    Under section 307(b)(1) of the CAA, petitions for judicial review 
of this action must be filed in the United States Court of Appeals for 
the appropriate circuit by December 12, 2022. Filing a petition for 
reconsideration by the Administrator of this final rule does not affect 
the finality of this action for the purposes of judicial review, does 
not extend the time within which a petition for judicial review may be 
filed, and shall not postpone the effectiveness of such rule or action. 
This action may not be challenged later in proceedings to enforce its 
requirements. See CAA section 307(b)(2).

List of Subjects in 40 CFR Part 52

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

Michael Regan,
Administrator.

    For the reasons stated in the preamble, 40 CFR part 52 is amended 
as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

0
2. Add Sec.  52.1189 to subpart X to read as follows:

Sec.  52.1189   Control strategy: Sulfur dioxide (SO2).

    (a) The plan submitted by the State on May 31, 2016 to attain the 
2010 1-hour primary sulfur dioxide (SO2) national

[[Page 61529]]

ambient air quality standard for the Detroit SO2 
nonattainment area does not meet the requirements of Clean Air Act 
(CAA) section 172 with respect to SO2 emissions from the 
U.S. Steel (Ecorse and Zug Island), EES Coke, Cleveland-Cliffs Steel 
Corporation (formerly AK or Severstal Steel), and Dearborn Industrial 
Generation (DIG) facilities in the Detroit, Michigan area. These 
requirements for these four facilities are satisfied by paragraphs 
(b)through(e) of this section, respectively.
    (b) This section addresses and satisfies CAA section 172 
requirements for the Detroit SO2 nonattainment area by 
specifying the necessary emission limits and other control measures 
applicable to the U.S. Steel Ecorse and Zug Island facilities. This 
section applies to the owner(s) and operator(s) of the facilities 
located at 1 Quality Drive and 1300 Zug Island Road in Detroit, 
Michigan. The requirements in this section for the Hot Strip Mill Slab 
Reheat Furnaces 1-5, No. 2 Baghouse, Main Plant Boiler No. 8, and Main 
Plant Boiler No. 9 apply to the owner and operator of the U.S. Steel 
Ecorse facility, and the requirements in this section for Boilerhouse 
1, Boilerhouse 2, A1 Blast Furnace, B2 Blast Furnace, D4 Blast Furnace, 
A/B Blast Furnace Flares, and D Furnace Flare apply to the owner and 
operator of the U.S. Steel Zug Island facility.
    (1) SO2 emission limits. (i) Beginning on the effective 
date of the FIP, no owner or operator shall emit SO2 from 
the following units in excess of the following limits:

                     Table 1 to Paragraph (b)(1)(i)
------------------------------------------------------------------------
                                                           SO2 emission
                          Unit                             limit  (lbs/
                                                                hr)
------------------------------------------------------------------------
Boilerhouse 1 (all stacks combined).....................           55.00
Hot Strip Mill--Slab Reheat Furnace 1...................            0.31
Hot Strip Mill--Slab Reheat Furnace 2...................            0.31
Hot Strip Mill--Slab Reheat Furnace 3...................            0.31
Hot Strip Mill--Slab Reheat Furnace 4...................            0.31
Hot Strip Mill--Slab Reheat Furnace 5...................            0.31
No. 2 Baghouse..........................................            3.30
Main Plant Boiler No. 8.................................            0.07
Main Plant Boiler No. 9.................................            0.07
A1 Blast Furnace........................................            0.00
B2 Blast Furnace........................................           40.18
D4 Blast Furnace........................................           40.18
A/B Blast Furnace Flares................................           60.19
D Furnace Flare.........................................           60.19
------------------------------------------------------------------------

    (ii) Beginning two years after the effective date of the FIP, no 
owner or operator shall emit SO2 from Boilerhouse 2 in 
excess of the following limits:
    (A) Boilerhouse 2 shall emit less than 750.00 lbs/hr unless 
Boilerhouse 1, A1 Blast Furnace, B2 Blast Furnace, D4 Blast Furnace, A/
B Blast Furnace Flares, or D Furnace Flare is operating, in which case 
it shall emit less than 81.00 lbs/hr.
    (B) [Reserved]
    (2) Stack restrictions and permit requirements. (i) The owner or 
operator shall construct a stack for Boilerhouse 2. The stack emission 
point must be at least 170 feet above ground level. The owner or 
operator shall submit a construction permit application for the stack 
to the State of Michigan within 90 days of the effective date of the 
FIP. Where any compliance obligation under this section requires any 
other state or local permits or approvals, the owner or operator shall 
submit timely and complete applications and take all other actions 
necessary to obtain all such permits or approvals.
    (ii) Beginning two years after the effective date of the FIP, no 
owner or operator shall emit SO2 from Boilerhouse 2, except 
from the stack emission point at least 170 feet above ground level.
    (3) Monitoring requirements. (i) Not later than two years after the 
effective date of the FIP, the owner or operator shall install and 
continuously operate an SO2 continuous emission monitoring 
system (CEMS) to measure SO2 emissions from Boilerhouse 2 in 
conformance with 40 CFR part 60, appendix F procedure 1.
    (ii) The owner or operator shall determine SO2 emissions 
from Boilerhouse 1, Hot Strip Mill Slab Reheat Furnaces 1-5, No. 2 
Baghouse, Main Plant Boiler No. 8, Main Plan Boiler No. 9, A1 Blast 
Furnace, B2 Blast Furnace, D4 Blast Furnace, A/B Blast Furnace Flares, 
and D Furnace Flare using mass balance calculations as described in 
paragraph (b)(4) of this section.
    (iii) Within 180 days of the installation of the CEMS specified in 
paragraph (b)(3)(i) of this section, the owner or operator shall 
perform an initial compliance test for SO2 emissions from 
Boilerhouse 2 while the boilerhouse is operating in accordance with the 
applicable emission limit during the period of testing identified in 
paragraph (b)(1)(ii) of this section. The initial compliance test shall 
be performed using EPA Test Method 6 at 40 CFR part 60, appendix A-4.
    (4) Compliance assurance plan. To determine compliance with the 
limits in paragraph (b)(1)(i) of this section, the owner or operator 
shall calculate hourly SO2 emissions using all raw material 
sulfur charged into each affected emission unit and assume 100 percent 
conversion of total sulfur to SO2. The owner or operator 
shall implement a compliance assurance plan (CAP) for all units except 
Boilerhouse 2 and any idled units that shall specify the calculation 
methodology, procedures, and inputs used in these calculations and 
submit the plan to EPA within 30 days after the effective date of the 
FIP. The owner or operator must submit a list of idled units to EPA 
within 30 days of the effective date of the FIP. The owner or operator 
must submit a CAP for any idled units prior to resuming operations.
    (5) Recordkeeping. The owner/operator shall maintain the following 
records continuously for five years beginning on the effective date of 
the FIP:
    (i) All records of production for each affected emission unit.
    (ii) All records of hourly emissions calculated in accordance with 
the CAP.
    (iii) In accordance with paragraphs (b)(3) of this section, all 
CEMS data, including the date, place, and time of sampling or 
measurement; parameters sampled or measured; and results.
    (iv) Records of quality assurance and quality control activities 
for emission monitoring systems including, but not limited to, any 
records required by 40 CFR part 60, appendix F Procedure 1.
    (v) Records of all major maintenance activities performed on 
emission units, air pollution control equipment, CEMS, and other 
production measurement devices.
    (vi) Any other records required by the Quality Assurance 
Requirements for Gas Continuous Emission Monitoring Systems Used for 
Compliance Determination rule at 40 CFR part 60, appendix F Procedure 1 
or the National Emission Standards for Hazardous Air Pollutants for 
Integrated Iron and Steel Manufacturing Facilities rule at 40 CFR part 
63, subpart FFFFF.
    (6) Reporting. Beginning on the effective date of the FIP, all 
reports under this section shall be submitted quarterly to Compliance 
Tracker, Air Enforcement and Compliance Assurance Branch, U.S. 
Environmental Protection Agency, Region 5, Mail Code AE-17J, 77 W. 
Jackson Blvd., Chicago, IL 60604-3590.
    (i) The owner or operator shall submit a CAP in accordance with 
paragraph (b)(4) of this section within 30 days of the effective date 
of the FIP.
    (ii) The owner or operator shall report CEMS data and hourly mass 
balance calculations quarterly in accordance

[[Page 61530]]

with CEMS requirements in paragraph (b)(3) of this section and the CAP 
requirements set forth in paragraph (b)(4) of this section no later 
than the 30th day following the end of each calendar quarter.
    (iii) The owner or operator shall report the results of the initial 
compliance test for the Boilerhouse 2 stack within 60 days of 
conducting the test.
    (iv) The owner or operator shall submit quarterly excess emissions 
reports for all units identified in paragraphs (b)(1)(i) and (ii) of 
this section no later than the 30th day following the end of each 
calendar quarter. Excess emissions means emissions that exceed the 
emission limits specified in paragraph (b)(1) of this section. The 
reports shall include the magnitude, date(s), and duration of each 
period of excess emissions, specific identification of each period of 
excess emissions that occurs during all periods of operation including 
startups, shutdowns, and malfunctions of the unit, the nature and cause 
of any malfunction (if known), and the corrective action taken, or 
preventative measures adopted.
    (v) The owner or operator of each unit shall submit quarterly CEMS 
performance reports, to include dates and duration of each period 
during which the CEMS was inoperative (except for zero and span 
adjustments and calibration checks), reason(s) why the CEMS was 
inoperative and steps taken to prevent recurrence, and any CEMS repairs 
or adjustments no later than the 30th day following the end of each 
calendar quarter.
    (vi) The owner or operator shall also submit results of any CEMS 
performance tests required by 40 CFR part 60, appendix F, Procedure 1 
(e.g., Relative Accuracy Test Audits, Relative Accuracy Audits, and 
Cylinder Gas Audits) no later than 30 days after the test is performed.
    (vii) When no excess emissions have occurred or the CEMS has not 
been inoperative, repaired, or adjusted during the reporting period, 
such information shall be stated in the quarterly reports required by 
paragraphs (b)(6) of this section.
    (c) This section addresses and satisfies CAA section 172 
requirements for the Detroit SO2 nonattainment area by 
specifying the necessary emission limits and other control measures 
applicable to the EES Coke facility. This section applies to the owner 
and operator of the facility located at 1400 Zug Island Road in 
Detroit, Michigan.
    (1) SO2 emission limits. Beginning on the effective date 
of the FIP, no owner or operator shall emit SO2 from the 
Underfire Combustion Stack EUCoke-Battery in excess of 544.6 lbs/hr, as 
a 3-hour average, and 2071 tons per year, on a 12-month rolling basis 
as determined at the end of each calendar month, and 0.702 pounds per 
1000 standard cubic feet of coke oven gas, as a 1-hour average.
    (2) Monitoring requirements. The owner or operator shall maintain 
and operate in a satisfactory manner a device to monitor and record the 
SO2 emissions from the Underfire Combustion Stack EUCoke-
Battery on a continuous basis. The owner or operator shall use 
Continuous Emission Rate Monitoring (CERM) data for determining 
compliance with the hourly limit in paragraph (c)(1) of this section. 
The owner or operator shall operate the CERM system in conformance with 
40 CFR part 60, appendix F.
    (d) This section addresses and satisfies CAA section 172 
requirements for the Detroit SO2 nonattainment area by 
specifying the necessary emission limits and other control measures 
applicable to the Cleveland-Cliffs Steel Corporation (formerly AK or 
Severstal Steel) facility. This section applies to the owner and 
operator of the facility located at 4001 Miller Road in Dearborn, 
Michigan.
    (1) SO2 emission limits. Beginning on the effective date 
of the FIP, no owner or operator shall emit SO2 from the 
following units in excess of the following limits:

                       Table 2 to Paragraph (d)(1)
------------------------------------------------------------------------
                                  SO2 emission limit     Time period/
              Unit                                    operating scenario
------------------------------------------------------------------------
``B'' Blast Furnace Baghouse      71.9 lbs/hr.......  Calendar day
 Stack.                                                average.
``B'' Blast Furnace Stove Stack.  38.75 lbs/hr......  Calendar day
                                                       average.
``B'' Blast Furnace Baghouse and  77.8 lbs/hr.......  Calendar day
 Stove Stacks (combined).                              average.
``B'' Blast Furnace Baghouse and  340 tons per year.  12-month rolling
 Stove Stacks (combined).                              time period as
                                                       determined at the
                                                       end of each
                                                       calendar month.
``C'' Blast Furnace Baghouse      179.65 lbs/hr.....  Calendar day
 Stack.                                                average.
``C'' Blast Furnace Stove Stack.  193.6 lbs/hr......  Calendar day
                                                       average.
``C'' Blast Furnace Baghouse and  271.4 lbs/hr......  Calendar day
 Stove Stacks (combined).                              average.
``C'' Blast Furnace Baghouse and  1188 tons per year  12-month rolling
 Stove Stacks (combined).                              time period as
                                                       determined at the
                                                       end of each
                                                       calendar month.
------------------------------------------------------------------------

    (2) Monitoring requirements. The owner or operator shall maintain 
and operate in a satisfactory manner a device to monitor and record the 
SO2 emissions and flow from ``B'' Blast Furnace and ``C'' 
Blast Furnace Baghouse and Stove Stacks on a continuous basis. The 
owner or operator shall use CERM data for determining compliance with 
the hourly limits in paragraph (d)(1) of this section. The owner or 
operator shall operate the CERM system in conformance with 40 CFR part 
60, appendix F.
    (e) This section addresses and satisfies CAA section 172 
requirements for the Detroit SO2 nonattainment area by 
specifying the necessary emission limits and other control measures 
applicable to the Dearborn Industrial Generation (DIG) facility. This 
section applies to the owner and operator of the facility located at 
2400 Miller Road in Dearborn, Michigan.
    (1) SO2 emission limits. (i) Beginning on the effective 
date of the FIP, no owner or operator shall emit SO2 from 
the following units in excess of the following limits:

[[Page 61531]]

                     Table 3 to Paragraph (e)(1)(i)
------------------------------------------------------------------------
                                  SO2 emission limit     Time period/
              Unit                                    operating scenario
------------------------------------------------------------------------
Boilers 1, 2, and 3 (combined)..  420 lbs/hr........  Daily average.
Boilers 1, 2, and 3 (combined)..  1839.6 tons per     12-month rolling
                                   year.               time period.
Boilers 1, 2, and 3 and Flares 1  840 lbs/hr........  Daily average.
 and 2 (combined).
Boilers 1, 2, and 3 and Flares 1  2947.7 tons per     12-month rolling
 and 2 (combined).                 year.               time period as
                                                       determined at the
                                                       end of each
                                                       calendar month.
------------------------------------------------------------------------

    (ii) [Reserved]
    (2) Monitoring requirements. (i) The owner or operator shall 
maintain and operate in a satisfactory manner a device to monitor and 
record the SO2 emissions from Boilers 1, 2, and 3 on a 
continuous basis. Installation and operation of each CEMS shall meet 
the timelines, requirements and reporting detailed in 40 CFR part 60, 
appendix F. If the owner or operator chooses to use a Predictive 
Emissions Monitoring System (PEMS) in lieu of a CEMS to monitor 
SO2 emissions, the permittee shall follow the protocol 
delineated in Performance Specification 16 in appendix B of 40 CFR part 
60.
    (ii) The owner or operator shall verify compliance with the 
emission limits for Boilers 1, 2 and 3 and Flares 1 and 2 (combined) by 
following the procedures and methodologies contained in the document 
entitled ``Protocol for Demonstrating Continuous Compliance with the 
Emission Limitations of ROP MI-ROP-N6631-2004'' dated May 31, 2011, or 
subsequent revisions to this document approved by EPA.

[FR Doc. 2022-21662 Filed 10-11-22; 8:45 am]
BILLING CODE 6560-50-P