Federal Register / Vol. 86, No. 156 / Tuesday, August 17, 2021 / Proposed Rules 45947 

• Is certified as not having a 

significant economic impact on a 

substantial number of small entities 

under the Regulatory Flexibility Act (5 

U.S.C. 601 et seq.); 

• Does not contain any unfunded 

mandate or significantly or uniquely 

affect small governments, as described 

in the Unfunded Mandates Reform Act 

of 1995 (Pub. L. 104–4); 

• Does not have federalism 

implications as specified in Executive 

Order 13132 (64 FR 43255, August 10, 

1999); 

• Is not an economically significant 

regulatory action based on health or 

safety risks subject to Executive Order 

13045 (62 FR 19885, April 23, 1997); 

• Is not a significant regulatory action 

subject to Executive Order 13211 (66 FR 

28355, May 22, 2001); 

• Is not subject to requirements of 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (15 U.S.C. 272 note) because 

application of those requirements would 

be inconsistent with the Clean Air Act; 

and 

• Does not provide EPA with the 

discretionary authority to address, as 

appropriate, disproportionate human 

health or environmental effects, using 

practicable and legally permissible 

methods, under Executive Order 12898 

(59 FR 7629, February 16, 1994). 

In addition, the SIP is not approved 

to apply on any Indian reservation land 

or in any other area where EPA or an 

Indian tribe has demonstrated that a 

tribe has jurisdiction. In those areas of 

Indian country, the rule does not have 

tribal implications and will not impose 

substantial direct costs on tribal 

governments or preempt tribal law as 

specified by Executive Order 13175 (65 

FR 67249, November 9, 2000). 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Carbon monoxide, 

Incorporation by reference, 

Intergovernmental relations, Lead, 

Nitrogen dioxide, Ozone, Particulate 

matter, Reporting and recordkeeping 

requirements, Sulfur oxides, Volatile 

organic compounds. 

Dated: August 11, 2021. 

Deborah Szaro, 

Acting Regional Administrator, EPA Region 

1. 

[FR Doc. 2021–17544 Filed 8–16–21; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R05–OAR–2020–0385; FRL–8826–01– 

R5] 

Air Plan Approval; Michigan; Sulfur 

Dioxide Clean Data Determination for 

St. Clair 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing to make a 

determination that the St. Clair sulfur 

dioxide (SO2) nonattainment area has 

attained the 2010 primary SO2 National 

Ambient Air Quality Standard (2010 

SO2 NAAQS). If finalized, this 

determination would suspend certain 

requirements for the nonattainment area 

for as long as the area continues to 

attain the 2010 SO2 NAAQS. 

DATES: Comments must be received on 

or before September 16, 2021. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–R05– 

OAR–2020–0385 at http://

www.regulations.gov, or via email to 

blakley.pamela@epa.gov. For comments 

submitted at Regulations.gov, follow the 

online instructions for submitting 

comments. Once submitted, comments 

cannot be edited or removed from 

Regulations.gov. For either manner of 

submission, EPA may publish any 

comment received to its public docket. 

Do not submit electronically any 

information you consider to be 

Confidential Business Information (CBI) 

or other information whose disclosure is 

restricted by statute. Multimedia 

submissions (audio, video, etc.) must be 

accompanied by a written comment. 

The written comment is considered the 

official comment and should include 

discussion of all points you wish to 

make. EPA will generally not consider 

comments or comment contents located 

outside of the primary submission (i.e., 

on the web, cloud, or other file sharing 

system). For additional submission 

methods, please contact the person 

identified in the FOR FURTHER

INFORMATION CONTACT section. For the 

full EPA public comment policy, 

information about CBI or multimedia 

submissions, and general guidance on 

making effective comments, please visit 

http://www2.epa.gov/dockets/ 

commenting-epa-dockets. 

FOR FURTHER INFORMATION CONTACT: 

Mary Portanova, Environmental 

Engineer, Control Strategies Section, Air 

Programs Branch (AR18J), 

Environmental Protection Agency, 

Region 5, 77 West Jackson Boulevard, 

Chicago, Illinois 60604, (312) 353–5954 

portanova.mary@epa.gov. The EPA 

Region 5 office 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. 

SUPPLEMENTARY INFORMATION: 

Throughout this document whenever 

‘‘we,’’ ‘‘us,’’ or ‘‘our’’ is used, we mean 

EPA. 

I. Background 

The St. Clair area was designated 

nonattainment for the 2010 SO2 NAAQS 

on July 12, 2016 (81 FR 45039), based 

on air quality modeling showing 

violations of the standard. The two SO2- 

emitting facilities in the St. Clair area 

are DTE Energy-Belle River (Belle River 

plant) and DTE Energy-St. Clair (St. 

Clair plant), which are both coal-fired 

power plants. The nonattainment area 

consists of a portion of southeastern St. 

Clair County, Michigan, located 

northeast of Detroit. The nonattainment 

area shares a border with Ontario, 

Canada along the St. Clair River. (See 

the area’s complete boundary 

description at 40 CFR 81.323). 

The Michigan Department of 

Environment, Great Lakes, and Energy 

(EGLE) was required to prepare a 

nonattainment State Implementation 

Plan (NA SIP) by March 12, 2018 to 

bring the St. Clair area into attainment 

by the attainment date of September 12, 

2021, but EGLE did not submit a 

complete NA SIP for the St. Clair area 

by the March 12, 2018 deadline. On 

September 20, 2019 (84 FR 49462), EPA 

issued a finding of failure to submit 

(FFS) a SIP required for attainment of 

the 2010 SO2 NAAQS. 

EGLE has informed EPA that DTE 

intends to close the St. Clair plant in 

2022, and use a new natural gas power 

plant, already under construction, to 

generate electric power in its place. This 

plant closure and replacement is 

expected to result in a large SO2

emission reduction for the area, but the 

expected SO2 reductions would not 

occur in time to be a timely element of 

the required 2018 NA SIP for the St. 

Clair area. Nevertheless, the September 

20, 2019 FFS resulted in the initiation 

of an 18-month clock toward imposition 

of sanctions for the state under CAA 

section 179, unless an approvable SO2

SIP is submitted and deemed complete 

by EPA. (See 40 CFR 52.31(d)(5)). In 

addition, the FFS started a two-year 

clock by which EPA is required under 

CAA section 110(c) to promulgate a 

Federal Implementation Plan (FIP) for 

the area, unless the state submits and 


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EPA approves a SIP for the area before 

that date. 

In the meantime, EGLE obtained air 

quality monitoring data in the St. Clair 

area which had not been available 

before the St. Clair area was designated 

nonattainment. On July 24, 2020, EGLE 

submitted a request that EPA make a 

determination under the Clean Air Act 

(CAA) and EPA’s Clean Data Policy, 

based on both local monitored air 

quality data and a new dispersion 

modeling analysis, that the St. Clair 

nonattainment area has attained the 

2010 SO2 NAAQS (Clean Data 

Determination). Approval of EGLE’s 

request would suspend the requirement 

for the state to submit certain planning 

elements otherwise required under CAA 

section 172(c) for a NA SIP for the St. 

Clair area, and suspend the sanctions 

and FIP clocks, for so long as the area 

continues to attain the 2010 SO2

NAAQS. EGLE would still be required 

to submit an emissions inventory (EI) 

required by CAA section 172(c)(3) and 

a nonattainment new source review 

(NNSR) program required by CAA 

section 172(c)(5), in order to avoid 

sanctions. EGLE submitted the St. Clair 

area’s EI and NNSR verification to EPA 

on June 30, 2021. 

II. Clean Data Determinations 

Following enactment of the CAA 

Amendments of 1990, EPA discussed its 

interpretation of the requirements for 

implementing the NAAQS in the 

General Preamble for the 

Implementation of title I of the CAA 

Amendments of 1990 (General 

Preamble), 57 FR 13498, 13564 (April 

16, 1992). In 1995, based on the 

interpretation of CAA sections 171, 172, 

and 182 in the General Preamble, EPA 

set forth what has become known as its 

‘‘Clean Data Policy’’ for the 1-hour 

ozone NAAQS. Under the Clean Data 

Policy, for a nonattainment area that can 

demonstrate attainment of the standard 

before implementing CAA 

nonattainment measures, EPA interprets 

the requirements of the CAA that are 

specifically designed to help an area 

achieve attainment, such as attainment 

demonstrations, implementation of 

reasonably available control measures, 

including reasonably available control 

technology (RACM/RACT), reasonable 

further progress (RFP) demonstrations, 

emissions limitations and control 

measures as necessary to provide for 

attainment, and contingency measures, 

to be suspended for so long as air 

quality continues to meet the standard. 

See the May 10, 1995 memorandum 

from John S. Seitz, Director, Office of 

Air Quality Planning and Standards, 

entitled, ‘‘Reasonable Further Progress, 

Attainment Demonstration, and Related 

Requirements for Ozone Nonattainment 

areas Meeting the Ozone National 

Ambient Air Quality Standard.’’ In an 

April 23, 2014 memorandum from Steve 

Page, Director of the EPA’s Office of Air 

Quality Planning and Standards, to the 

EPA Air Division Directors entitled, 

‘‘Guidance for 1-hr SO2 Nonattainment 

Area SIP Submissions’’ (2014 SO2

Nonattainment Area Guidance), EPA 

provides guidance and a rationale for 

the application of the Clean Data Policy 

to the 2010 1-hour primary SO2

NAAQS. 

A state may notify EPA that it believes 

a nonattainment area is attaining the 

2010 SO2 NAAQS and request a clean 

data determination under EPA’s Clean 

Data Policy. EPA will determine 

whether the area has attained the 2010 

SO2 NAAQS based on available 

information, including available air 

quality monitoring data and air quality 

dispersion modeling information for the 

affected area. If the determination of 

attainment is granted, then requirements 

for the area such as a nonattainment SIP 

submittal or reasonable further progress 

measures are suspended for so long as 

the area continues to attain the NAAQS. 

Provided the area has submitted a 

complete EI and NNSR program, 

sanctions for failing to timely submit a 

SIP are also suspended for so long as the 

area remains in attainment. 

However, the suspension of the 

obligations to submit attainment 

planning related SIPs is only 

appropriate where the area remains in 

attainment of the NAAQS. EPA is 

proposing to require EGLE to submit 

annual statements by July 1 to EPA, to 

address whether the St Clair area has 

continued to attain the 2010 SO2

NAAQS. EPA expects that these 

statements could include such 

information as available air quality 

monitoring data or an assessment of 

changes in facility emissions or 

operations and whether these changes 

warrant updated modeling. If EPA does 

not receive credible information 

indicating that the area continues to 

attain the SO2 NAAQS, EPA will 

propose to rescind the St. Clair area’s 

clean data determination, the 

finalization of which would lift the 

suspension of its attainment planning 

requirements and would reinstate the 

sanctions and FIP clocks with their 

original deadlines. 

The determination of attainment 

under the Clean Data Policy does not 

serve to alter the area’s nonattainment 

designation. Clean data determinations 

are not redesignations to attainment. For 

EPA to redesignate an area to 

attainment, the area must meet the 

requirements of CAA section 107(d)(3) 

and demonstrate maintenance as 

required by CAA section 175A. 

III. Analysis of EGLE’s Request 

EGLE’s July 24, 2020 request for a 

clean data determination included local 

monitoring data and a dispersion 

modeling analysis for the St. Clair 

nonattainment area. The 2014 SO2

Nonattainment Area Guidance states 

that when air agencies provide 

monitoring and/or modeling to support 

clean data determinations, the 

monitoring data provided by the state 

should follow EPA’s ’’SO2 NAAQS 

Designations Source-Oriented 

Monitoring Technical Assistance 

Document’’ (SO2 Monitoring TAD) and 

the modeling provided by the state 

should follow EPA’s ‘‘SO2 NAAQS 

Designations Modeling Technical 

Assistance Document’’ (SO2 Modeling 

TAD). 

The Monitoring TAD was provided by 

EPA to assist states in siting monitors to 

characterize ambient air quality 

impacted by significant SO2 sources, 

with the goal to identify peak SO2

concentrations attributable to those 

sources. Collaboration with other 

stakeholders such as affected industry 

was encouraged in the Monitoring TAD. 

The Monitoring TAD suggests that 

existing industry monitoring operations 

could be found to meet the necessary 

requirements to produce data of 

appropriate quality for comparison to 

the NAAQS. Industrial monitors should 

be appropriately sited and operated in a 

manner largely equivalent to those 

monitors operated elsewhere in the 

State and Local Air Monitoring Stations 

(SLAMS) network, meeting applicable 

criteria in 40 CFR part 58, appendices 

A, C, and E and reporting their data to 

the Air Quality Subsystem (AQS). 

EGLE’s July 24, 2020 submittal 

included three years of monitoring data 

from two industrial monitors located in 

the St. Clair nonattainment area, near 

the power plants. DTE installed the two 

SO2 monitors in the St. Clair 

nonattainment area in 2016 to evaluate 

SO2 impacts from the two facilities. The 

monitors were sited using dispersion 

modeling to help identify the locations 

of predicted maximum SO2

concentrations. Considering the monitor 

siting guidance in the Monitoring TAD, 

EPA believes that these monitors’ 

locations adequately represent the 

locations of potential maximum SO2

impacts from the two power plants. One 

monitor, known as the Remer monitor, 

is sited near the St. Clair River, between 

and slightly north of the two power 

plants, about one kilometer (km) from 

each plant. Previously modeled 


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maximum SO2 concentrations have been 

predicted at or near this location. The 

other monitor, known as the Mills 

monitor, is sited 3 km west of the Belle 

River plant, so that it can capture the 

worst-case combined impacts when 

winds are blowing from the St. Clair 

plant toward the Belle River plant. 

EPA reviewed the ambient air 

monitoring data for the 2017–2019 

period, which were the three most 

recent full calendar years of data 

available. Ambient and quality 

assurance data for these two monitoring 

sites are recorded in EPA’s AQS 

database. EGLE and EPA have reviewed 

the data and have determined that this 

data meets completeness and data 

quality indicators confirm that the data 

is suitable to be used in support of a 

clean data determination for the St. 

Clair area. 

The data cited by EGLE in its request 

show attainment of the 2010 SO2

NAAQS at both monitors for the 2017– 

2019 time period, with three-year 

average 99th percentile daily maximum 

1-hour concentrations (design values) of 

54 and 45 parts per billion (ppb), which 

are below the 2010 SO2 NAAQS of 75 

ppb. Data for 2020 indicate that the 

monitors have continued to show 

attainment. Table 1 shows the 2017– 

2020 SO2 monitoring results for the St. 

Clair area monitors. 

TABLE 1—2017–2020 MONITORED SO2 VALUES IN THE ST. CLAIR AREA

Monitor 

Annual 99th percentile (ppb) 2017–2019 

design value 

(ppb) 

2018–2020 

design value 

2017 2018 2019 2020 (ppb) 

Mills Monitor ............................................. 46 50 40 29 45 40 

Remer Monitor ......................................... 51 65 45 25 54 45 

EPA also reviewed the dispersion 

modeling analysis for the St. Clair area 

which EGLE submitted on July 24, 2020. 

The SO2 Modeling TAD outlines 

modeling approaches for SO2 NAAQS 

attainment status designations and 

states that, for the purposes of modeling 

to characterize air quality for use in SO2

designations, EPA recommends using a 

minimum of the most recent three years 

of actual emissions data and concurrent 

meteorological data to allow the 

modeling to simulate what a monitor 

would observe. 

EGLE’s analysis followed the 

Modeling TAD and modeled the 

impacts of the Belle River and St. Clair 

plants in the St. Clair nonattainment 

area. EGLE used the actual 2017–2019 

hourly SO2 emissions for the Belle River 

and St. Clair plants as measured by 

continuous emissions monitor (CEM) 

data. EGLE also characterized the 

buildings at the two plants using the 

AERMOD component BPIPPRM, to 

address building downwash. There were 

no additional nearby sources that were 

expected to produce a significant SO2

concentration gradient in the 

nonattainment area. 

To model the St. Clair nonattainment 

area, EGLE used EPA’s AERMOD model, 

version 19191, with meteorological data 

for 2017–2019 from the Oakland County 

International Airport (Pontiac), located 

75 km to the west of the St. Clair plants. 

This meteorological data set is 

considered to be representative of the 

St. Clair area. The area was modeled as 

rural, based on local land use 

characteristics. Terrain information was 

included in the modeling analysis. The 

nonattainment area is flat and mostly 

residential or agricultural. The river 

valley is not deep, although some wind 

channeling could occur. The 

geographical and topographical features 

of the area are not considered to 

significantly impact air pollution 

transport. The St. Clair modeling 

analysis used a nested receptor grid 

with resolution from 50 meters near the 

facilities to 100 meters in the central 

portion, and then 250 meters to the edge 

of the modeling domain, 10 km from the 

power plants. 

For a background concentration for 

the modeling analysis, EGLE used 

monitored SO2 data from Michigan’s 

SO2 monitor in Port Huron, located 21 

km to the north of the St. Clair plants. 

The Port Huron monitor has an SO2

design value of 67 ppb for 2017–2019. 

EGLE determined its background 

concentration using a temporally 

varying approach to characterize 

background SO2 emissions, based on the 

99th percentile monitored 

concentrations by season and hour of 

day. In this analysis, EGLE used data 

measured when winds were blowing 

from wind direction sectors which were 

chosen to avoid double-counting 

emissions from the St. Clair and Belle 

River plants and to avoid overestimating 

impacts from sources which are located 

in Canada, 3–5 km east of Port Huron 

but 15–20 km from the St. Clair area. 

The Modeling TAD provides for this 

approach. At such distances, the 

Canadian sources are not expected to 

provide a significant concentration 

gradient in the St. Clair area. The 

modeling analysis’ results match well 

with the monitored values near the St. 

Clair plants, which suggests that the 

modeling analysis is not missing 

significant additional ambient 

contributions at those locations. 

Therefore, EPA concurs with the 

background values EGLE used in its 

analysis. The background 

concentrations for the St. Clair modeling 

analysis were determined to vary from 

1.3 to 6.5 ppb, with an average value of 

2.4 ppb. 

The state’s modeling resulted in a 

three-year maximum predicted 99th 

percentile daily maximum 1-hour 

concentration of 64.4 ppb, including 

background. This design value was 

predicted at a receptor located very near 

the St. Clair plant. As the predicted 

design value is below the 2010 SO2

NAAQS of 75 ppb, the state’s modeling 

demonstrates attainment of the 2010 

SO2 NAAQS. 

EGLE’s modeling results for receptors 

placed at the two SO2 monitors’ 

locations matched well with the actual 

monitored design values. The model’s 

predicted design value at the Remer 

monitor location was 47.7 ppb, 

compared to the monitored design value 

of 45 ppb, and the model’s predicted 

design value at the Mills monitor 

location was 52.7 ppb, compared to the 

monitored design value of 54 ppb. The 

location of the maximum modeled 99th 

percentile concentration was less than 

half a kilometer from the Remer 

monitor, which lends support to EPA’s 

expectation that the Remer monitor is 

located in the area of expected 

maximum concentrations. Other areas of 

predicted high concentrations were at 

approximately the same distance to the 

northwest and west of the power plants 

as the Mills monitor, again lending 

support to EPA’s expectation that the 

Mills monitor location is also 

representative of areas of high expected 

concentrations. 

After reviewing EGLE’s July 24, 2020 

submittal, EPA proposes to find that the 

St. Clair area has attained the 2010 SO2

NAAQS and satisfies the requirements 

of the Clean Data Policy. 


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IV. What action is EPA taking? 

EPA is proposing to approve EGLE’s 

request for a Clean Data Determination 

for the St. Clair nonattainment area in 

St. Clair County, Michigan. Finalizing 

this determination would suspend the 

requirements for EGLE to submit an 

attainment demonstration and other 

associated nonattainment planning 

requirements for so long as the St. Clair 

nonattainment area continues to attain 

the 2010 SO2 NAAQS. This proposed 

action is consistent with EPA’s longheld interpretation of CAA 

requirements. 

Finalizing this action would not 

constitute a redesignation of the St. 

Clair area to attainment of the 2010 SO2

NAAQS under section 107(d)(3) of the 

CAA. The St. Clair area will remain 

designated nonattainment for the 2010 

SO2 NAAQS until such time as EPA 

determines that the area meets the CAA 

requirements for redesignation to 

attainment and takes action to 

redesignate the area. 

V. Statutory and Executive Order 

Reviews 

This action proposes to make a clean 

data determination for the St. Clair area 

for the 2010 SO2 NAAQS based on air 

quality data which would result in the 

suspension of certain Federal 

requirements and does not impose any 

additional requirements. For that 

reason, this action: 

• Is not a significant regulatory action 

subject to review by the Office of 

Management and Budget under 

Executive Orders 12866 (58 FR 51735, 

October 4, 1993) and 13563 (76 FR 3821, 

January 21, 2011); 

• Does not impose an information 

collection burden under the provisions 

of the Paperwork Reduction Act (44 

U.S.C. 3501 et seq.); 

• Is certified as not having a 

significant economic impact on a 

substantial number of small entities 

under the Regulatory Flexibility Act (5 

U.S.C. 601 et seq.); 

• Does not contain any unfunded 

mandate or significantly or uniquely 

affect small governments, as described 

in the Unfunded Mandates Reform Act 

of 1995 (Pub. L. 104–4); 

• Does not have federalism 

implications as specified in Executive 

Order 13132 (64 FR 43255, August 10, 

1999); 

• Is not an economically significant 

regulatory action based on health or 

safety risks subject to Executive Order 

13045 (62 FR 19885, April 23, 1997); 

• Is not a significant regulatory action 

subject to Executive Order 13211 (66 FR 

28355, May 22, 2001); 

• Is not subject to requirements of 

Section 12(d) of the National 

Technology Transfer and Advancement 

Act of 1995 (15 U.S.C. 272 note) because 

application of those requirements would 

be inconsistent with the CAA; and 

• Does not provide EPA with the 

discretionary authority to address, as 

appropriate, disproportionate human 

health or environmental effects, using 

practicable and legally permissible 

methods, under Executive Order 12898 

(59 FR 7629, February 16, 1994). 

In addition, the SIP is not approved 

to apply on any Indian reservation land 

or in any other area where EPA or an 

Indian tribe has demonstrated that a 

tribe has jurisdiction. In those areas of 

Indian country, the rule does not have 

tribal implications and will not impose 

substantial direct costs on tribal 

governments or preempt tribal law as 

specified by Executive Order 13175 (65 

FR 67249, November 9, 2000). 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Intergovernmental relations, 

Sulfur oxides. 

Dated: August 9, 2021. 

Cheryl Newton, 

Acting Regional Administrator, Region 5. 

[FR Doc. 2021–17546 Filed 8–16–21; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Parts 52 and 81 

[EPA–R07–OAR–2021–0391; FRL–8693–03– 

R7] 

Air Plan Approval; Missouri 

Redesignation Request and 

Associated Maintenance Plan for the 

Jefferson County 2010 SO2 1-Hour 

NAAQS Nonattainment Area; 

Reopening of Comment Period 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule; reopening of 

comment period. 

SUMMARY: On June 29, 2021, the 

Environmental Protection Agency (EPA) 

proposed a rule titled, ‘‘Air Plan 

Approval; Missouri Redesignation 

Request and Associated Maintenance 

Plan for the Jefferson County 2010 SO2

1-Hour NAAQS Nonattainment Area.’’ 

In response to stakeholder requests, the 

EPA is reopening the comment period 

for this proposed rule. 

DATES: The comment period for the 

proposed rule published on June 29, 

2021 (86 FR 34177), is reopened. 

Written comments must be received on 

or before September 16, 2021. 

ADDRESSES: You may send comments, 

identified by Docket ID No. EPA–R07– 

OAR–2021–0391 to https://

www.regulations.gov. Follow the online 

instructions for submitting comments. 

Instructions: All submissions received 

must include the Docket ID No. for this 

rulemaking. Comments received will be 

posted without change to https://

www.regulations.gov, including any 

personal information provided. For 

detailed instructions on sending 

comments and additional information 

on the rulemaking process, see the 

‘‘Written Comments’’ heading of the 

SUPPLEMENTARY INFORMATION section of 

this document. 

FOR FURTHER INFORMATION CONTACT: 

Ashley Keas, Environmental Protection 

Agency, Region 7 Office, Air Quality 

Planning Branch, 11201 Renner 

Boulevard, Lenexa, Kansas 66219 at 

(913) 551–7629, or by email at: 

keas.ashley@epa.gov. 

SUPPLEMENTARY INFORMATION: On June 

29, 2021, the EPA published in the 

Federal Register (86 FR 34177), a notice 

of proposed rulemaking, proposing to 

approve the State of Missouri’s 

December 27, 2017, request for the EPA 

to redesignate the Jefferson County, 

Missouri, 2010 1-hour sulfur dioxide 

(SO2) National Ambient Air Quality 

Standard (NAAQS) nonattainment area 

to attainment and to approve a State 

Implementation Plan (SIP) revision 

containing a maintenance plan for the 

area. The State provided supplemental 

information on: May 15, 2018; February 

7, 2019; February 25, 2019; and April 9, 

2021. In response to these submittals, on 

June 28, 2021, the EPA proposed to take 

the following actions: Approve the 

State’s plan for maintaining attainment 

of the 2010 1-hour SO2 primary 

standard in the area; and approve the 

State’s request to redesignate the 

Jefferson County SO2 nonattainment 

area to attainment for the 2010 1-hour 

SO2 primary standard. 

For more detailed information about 

this matter, please refer to the June 29, 

2021 Federal Register document. 

The notice of proposed rulemaking, as 

initially published in the Federal 

Register, provided for written comments 

to be submitted to the EPA on or before 

July 29, 2021 (a 30-day public comment 

period). Since publication, the EPA was 

made aware that the Technical Support 

Document (TSD) associated with the 

proposed rule was not included in the 

docket. The TSD was uploaded to the 

docket on July 18, 2021. Subsequently, 

the EPA received stakeholder requests 


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