13022 Federal Register / Vol. 89, No. 35 / Wednesday, February 21, 2024 / Proposed Rules 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R03–OAR–2024–0047; FRL–9920–01– 

R3] 

Air Plan Disapproval; Pennsylvania; 

Reasonably Available Control 

Technology Case-by-Case Permits for 

Keystone, Conemaugh and Homer City 

Generating Facilities for the 1997 and 

2008 Ozone National Ambient Air 

Quality Standards 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Proposed rule. 

SUMMARY: The Environmental Protection 

Agency (EPA) is proposing to 

disapprove state implementation plan 

(SIP) revisions submitted by the 

Pennsylvania Department of 

Environmental Protection (PADEP) on 

behalf of the Commonwealth of 

Pennsylvania (Pennsylvania). PADEP 

submitted SIP revisions for the 

Keystone, Conemaugh and Homer City 

electric generating facilities on May 26, 

2022 to address certain reasonably 

available control technique (RACT) 

requirements for the 1997 and 2008 

ozone national ambient air quality 

standards (NAAQS). EPA is proposing 

to disapprove the May 26, 2022 SIP 

revisions for these facilities as the SIPs 

contain problematic provisions and fail 

to justify the selection of permit limits 

as RACT consistent with applicable 

requirements and case law. This action 

is being taken under the Clean Air Act 

(CAA). 

DATES: Written comments must be 

received on or before March 22, 2024. 

ADDRESSES: Submit your comments, 

identified by Docket ID No. EPA–R03– 

OAR–2024–0047 at https://

www.regulations.gov, or via email to 

gordon.mike@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 

https://www.epa.gov/dockets/ 

commenting-epa-dockets. 

FOR FURTHER INFORMATION CONTACT: 

Sean Silverman, Planning & 

Implementation Branch (3AD30), Air & 

Radiation Division, U.S. Environmental 

Protection Agency, Region III, 1600 John 

F. Kennedy Boulevard, Philadelphia, 

Pennsylvania 19103. The telephone 

number is (215) 814–5511. Mr. 

Silverman can also be reached via 

electronic mail at silverman.sean@

epa.gov. 

SUPPLEMENTARY INFORMATION: 

I. Background 

The RACT requirements in CAA 

section 182(b)(2) apply to all ozone 

nonattainment areas classified as 

Moderate or higher (i.e. Serious, Severe, 

or Extreme). Section 184(b)(1)(B) of the 

CAA also applies RACT to all areas 

located within ozone transport regions. 

The entire Commonwealth of 

Pennsylvania is part of the Ozone 

Transport Region (OTR) established by 

section 184 of the CAA and therefore 

subject statewide to RACT 

requirements. 

On May 16, 2016, Pennsylvania 

submitted a SIP revision intended to 

satisfy CAA sections 182(b)(2)(C), 182(f), 

and 184 for the 1997 and 2008 8-hour 

ozone NAAQS for all major sources of 

nitrogen oxides (NOX) and volatile 

organic compounds (VOCs) in 

Pennsylvania not subject to control 

techniques guidelines (CTGs), with a 

few exceptions not relevant to this 

action. On May 9, 2019, EPA published 

a final action fully approving certain 

provisions and conditionally approving 

other portions of Pennsylvania’s May 

16, 2016, SIP submission to implement 

RACT for the 1997 and 2008 Ozone 

NAAQS (hereafter the ‘‘RACT II rule’’). 

84 FR 20274 (May 9, 2019). Specifically, 

EPA’s action fully approved sections 

121.1, 129.96, 129.97, and 129.100 of 

Title 25 of the Pennsylvania Code (25 

Pa. Code) as meeting certain aspects of 

major stationary source RACT in CAA 

sections 172, 182, and 184 for the 1997 

and 2008 ozone NAAQS, and 

conditionally approved 25 Pa. Code 

sections 129.98 and 129.99 following a 

commitment provided by Pennsylvania 

to submit additional SIP revisions to 

address the deficiencies identified by 

EPA in the May 16, 2016 SIP revision. 

Id. at 20290. 

On August 27, 2020, the Third Circuit 

held unlawful and vacated EPA’s 

approval of certain SIP provisions 

challenged by the Sierra Club. Sierra 

Club v. EPA, 972 F.3d 290 (3rd Cir. 

2020) (‘‘Sierra Club’’). The case related 

to EPA’s approval of only that portion 

of the RACT II rule applicable to coalfired electricity generating units (EGUs) 

equipped with selective catalytic 

reduction (SCR) for control of NOX. 

Specifically at issue was EPA’s approval 

of the presumptive RACT NOX limit for 

these EGUs of 0.12 pounds of NOX per 

Million British Thermal Units (MMBtu) 

of heat input (lbs/MMBtu) when the 

inlet temperature to the SCR was 600 

degrees Fahrenheit or above, found at 25 

Pa. Code 129.97(g)(1)(viii); the 

application of the less stringent NOX

limits of 25 Pa Code 129.97(g)(1)(vi) to 

EGUs with SCR when the inlet 

temperature to the SCR was below 600 

degrees Fahrenheit; and the failure of 

the RACT II rule at 25 Pa. Code 

129.100(d) to specifically require these 

EGUs to keep temperature data for the 

inlet temperature to the SCRs and report 

that data to PADEP. 

The Court explained that, while 

RACT does not require the lowest 

achievable emissions limit, 

Pennsylvania’s adoption of a limit 

derived from the average historical NOX

emissions of the units at these EGUs, 

without more, was insufficient. The 

record showed that certain units within 

Pennsylvania were capable of achieving 

significantly lower rates of NOX

emissions. The Court found that EPA 

did not sufficiently explain why a lower 

standard was infeasible. Sierra Club, 

972 F.3d at 299–303. Second, the Court 

held that Pennsylvania’s standard acted 

as a loophole because it permitted 

unlimited operations without the use of 

SCR controls if exhaust gas temperature 

was kept below what the Court 

considered an arbitrary temperature 

threshold of 600 degrees Fahrenheit. Id. 

at 303–07. Third, the Court held that 

Pennsylvania’s reporting requirements 

were not enforceable. Id. at 307–09. 

Consequently, the Court vacated 

EPA’s approval of this portion of the 

2016 SIP and ordered EPA either to 

approve a revised, compliant SIP or 

promulgate a FIP within two years (i.e., 

by August 27, 2022). Sierra Club at 309. 

The Court stated that the new 

standard—SIP or FIP—‘‘must be 

technology forcing, in accord with 

[EPA’s] RACT standard, and lack the 

gaping loophole found in the [2016 

SIP’s] enforcement regime.’’ Id. On 

August 16, 2022, EPA took final action 


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1See ‘‘Conemaugh RACT II Review Memo’’ p. 2, 

‘‘Homer City RACT II Review Memo’’ p. 3 and 

‘‘Keystone RACT II Review Memo’’ p. 2, available 

in the docket of this action. 

2The Bruce Mansfield EGUs ceased all operations 

prior to April 1, 2021 and therefore did not submit 

a RACT permit application. 

3See 51 Pa.B. 5834, September 11, 2021 

(Keystone); 51 Pa.B. 6259, October 2, 2021 

(Conemaugh); 51 Pa.B. 6558, October 16, 2021 

(Homer City); 51 Pa.B. 6930, November 6, 2021 

(Montour); Allegheny County Health Department 

Public Notices, December 2, 2021 (Cheswick). 4See document dated October 26, 2022 from EPA 

Region III to Acting Secretary Ramez Ziadeh of 

PADEP available in the docket of this action. 

5See document dated April 15, 2022 from 

Allegheny County to Lee Bahl of GenOn Holdings 

LLC available in the docket of this action. 

6See https://www.pjm.com/planning/servicerequests/gen-deactivations. 

7All three Response to Comments (RTC) 

documents are in the docket for this matter. The 

Conemaugh Response to Comments (Con RTC) and 

Keystone Response to Comments (Key RTC) are 

both dated May 12, 2022. The Homer City Response 

to Comments (HC RTC) in the official SIP 

submission is marked ‘‘Draft’’ and does not contain 

a date. 

8See, e.g., Conemaugh Response to Comments, p. 

2: ‘‘incorporates the provisions and requirements 

contained in the amended RACT II approval for the 

facility, which are intended to satisfy the [CAA] 

RACT requirements for the 1997 and 2008 . . . 

ozone [NAAQS].’’ 

to disapprove the vacated portions of 

the May 19, 2020 approval. 87 FR 

50257. EPA published its proposed FIP 

on May 25, 2022. 87 FR 31798. EPA 

issued a FIP on August 31, 2022. 87 FR 

53381. 

Following the Court’s decision, 

PADEP required that by April 1, 2021, 

each source within a facility which had 

been subject to the presumptive 0.12 lb/ 

MMBtu limit submit a permit 

application in accordance with 25 Pa. 

Code 129.99 setting forth a RACT 

analysis for each unit at the facility.1 On 

or about April 1, 2021, Conemaugh, 

Homer City, Keystone, and Montour 

submitted permit applications to PADEP 

with RACT analyses.2 PADEP found the 

permit applications to be technically 

deficient and therefore issued technical 

deficiency letters to each of these 

sources seeking additional information. 

Although the sources submitted 

additional information, PADEP decided 

that it would do its own case-by-case 

RACT analysis for each EGU at each 

facility and propose new RACT limits 

for each EGU in amended title V 

permits. Once these permits became 

final, PADEP intended to submit each 

permit to EPA as a SIP revision to meet 

the RACT requirement for each source. 

EPA also continued to regularly discuss 

with PADEP their efforts to develop 

case-by-case RACT/title V permits for 

these sources. 

From September 11, 2021, through 

November 6, 2021, PADEP serially 

issued draft RACT/title V permits for 

four sources, while Allegheny County 

issued a draft RACT/title V permit for 

Cheswick in December 2021.3 EPA 

submitted timely comments on each 

draft permit. Many of the concerns and 

issues identified in EPA’s first set of 

comments (which was on the Keystone 

permit) appeared again in the draft 

permits for the other sources. EPA’s 

comments raised significant concerns 

over the approvability of each permit 

because each remained inconsistent 

with the court’s decision, and PADEP 

did not address those concerns with 

each subsequent draft permit it 

published for comment. On May 26, 

2022, PADEP submitted case-by-case 

RACT determinations to EPA as a 

revision to the Pennsylvania SIP which 

still contained the approvability issues 

EPA had flagged in its comments, for 

Keystone, Conemaugh, and Homer City. 

PADEP submitted a case-by-case RACT 

determination for Montour as a revision 

to the Pennsylvania SIP on June 9, 2022, 

but subsequently formally withdrew it.4

In addition, the Cheswick facility 

permanently ceased operations and 

surrendered all of its air permits to the 

Allegheny County Health Department.5

The Homer City facility also ceased all 

coal-burning operations on July 1, 

2023.6 Prior to July 1st, only Unit 3 at 

Homer City was operating. However, 

because Homer City has not formally 

surrendered its CAA permits, which 

would demonstrate that the shutdown is 

permanent, and because PADEP has not 

withdrawn the SIP submission with 

regard to Homer City, EPA will continue 

to consider the approvability of the 

RACT NOX limits for Homer City. 

EPA notes that the May 2022 permits 

for Keystone and Conemaugh also 

contain case-by-case RACT limits for 

certain gas or oil-fired auxiliary boilers 

at these facilities. However, EPA is not 

taking action at this time on the case-bycase RACT limits in these permits for 

two auxiliary boilers at Keystone 

(Source IDs 037 and 038) and the two 

at Conemaugh (Source IDs 039 and 041). 

These auxiliary boilers were not subject 

to the presumptive RACT limit in 25 Pa. 

Code 129.97(g)(1)(viii) for which EPA 

issued a final disapproval in August 

2022. 

II. Summary of the Case-by-Case Permit 

SIP Revisions 

EPA notes that the RACT limits in 

PADEP’s May 2022 SIP submittal 

addressed RACT limits for the large 

Electric Generating Units (EGUs) at 

Conemaugh, Keystone, and Homer City 

for only the 1997 and 2008 ozone 

NAAQS. These source-specific limits 

were established pursuant to 25 Pa. 

Code 129.99, which was conditionally 

approved by EPA in March 2019. 

Section 129.99 of 25 Pa. Code allows a 

source to apply for an alternative RACT 

limit (a.k.a. ‘‘case-by-case’’ RACT limit) 

to the otherwise default (a.k.a. 

‘‘presumptive’’) RACT limits where 

appropriate. In response to comments,7

PADEP affirmed that the RACT limits 

for the EGUs at these three sources do 

not address the 2015 ozone NAAQS.8

Summary of Pennsylvania’s Process for 

Setting Limits 

PADEP developed the NOX limits for 

each of the EGUs at each facility using 

a similar methodology, which included 

using similar years of data. Table 1 in 

this document summarizes the three 

NOX emission rates applicable to each 

unit at each facility as proposed by 

Pennsylvania for public comment, and 

the final limits in the permits submitted 

by PADEP for approval as SIP revisions. 

TABLE 1—PROPOSED RATES AND FINAL RATES IN 2022 PA SIP SUBMISSION

Facility Unit Capacity 

Proposed limits Submitted as SIP revision (final) 

SCR on 

lb/MMBtu 

daily avg. 

All 

conditions 

lb/MMBtu 

daily avg. 

All 

conditions 

lb/hr 

30-day avg. 

SCR on 

lb/MMBtu 

daily avg. 

All 

conditions 

lb/MMBtu 

daily avg. 

All 

conditions 

lb/hr 

30-day avg. 

Conemaugh .................................... 1 ....... 8,280 0.070 0.27 700 0.070 0.27 700 

2 ....... 8,280 0.070 0.27 700 0.070 0.27 700 

Keystone ......................................... 1 ....... 8,717 0.080 0.30 800 0.080 0.30 770 

2 ....... 8,717 0.080 0.30 800 0.080 0.30 770 

Homer City ...................................... 1 ....... 6,792 0.080 0.45 550 0.080 0.45 600 

2 ....... 6,792 0.080 0.45 550 0.080 0.45 600 

3 ....... 7,260 0.070 0.27 510 0.070 0.27 560 


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9All three technical evaluation memos (TEMs) 

are in the docket for this matter. The Homer City 

technical evaluation memo (HC TEM) is dated 

October 14, 2021. The Conemaugh technical 

evaluation memo (Con TEM) is dated September 28, 

2021. The Keystone technical evaluation memo 

(Key TEM) is dated August 25, 2021. 

10Potential controls evaluated included: 

Precombustion Controls (Switching to Natural Gas, 

Switching from high to low emitting or zero 

emitting units), Combustion Controls (Partial or full 

oxy firing, Oxygen enhanced combustion, LNB 

installation, LNB Optimization, LNB Upgrade, Flue 

Gas Recirculation (FGR), Separated overfired air, 

Rotating opposed fire air) Post Combustion Controls 

(Additional SCR, SCR Optimization, Economizer 

Bypass during low load, startup, and shutdown to 

allow SCR operation, V-temp economizer during 

low load, startup, and shutdown to allow SCR 

operation, Flue gas reheat during low load, startup, 

and shutdown to allow SCR operation, Dry sorbent 

injection prior to SCR during low load conditions 

to allow SCR operation, addition of Selective NonCatalytic Reduction (SNCR), SNCR Optimization, 

Return of partially operating SCR and SNCR 

systems to full operation) Station Wide 

Improvements (Installation/improvement of digital 

process controls on equipment to minimize NOX

emissions and detect equipment in need to 

maintenance, Improved/increased equipment 

cleaning and maintenance practices). See Con TEM 

p. 4–19; Key TEM, pp 3–17; HC TEM pp. 3–21. 

11Note that Key TEM p. 3, Con TEM p. 3 and HC 

TEM p. 4, state that the years reviewed are 2017– 

2020, but Key RTC p. 8, Con RTC p. 9 and HC RTC 

p. 7 state years reviewed were 2016–2020. 

12For Keystone, the months examined were May 

2017 and April 2018. Key TEM pp. 3–6. For Homer 

City, the months were June 2019 (unit 1), July of 

2019 and 2020 (unit 2), and December 2017, July 

2019, September 16, 2019 and Dec. 4, 2019 (unit 3). 

HC TEM, pp. 4–14. For Conemaugh, dates 

examined included May 2017, September 5, 2019, 

and April 4, 2020. Con TEM pp. 3–8. 

13Con TEM, pp. 3–8; Key TEM, pp. 3–7; HC TEM, 

pp. 4–13. 

14The other factors PADEP cites are varying 

loads, operating load, catalyst condition, exhaust 

temperature and velocity, moisture level, initial 

NOX levels in the exhaust, and other unnamed 

factors. HC TEM, p. 13. 

A technical evaluation memo (TEM) 

accompanying each draft permit issued 

for public comment provided an initial 

explanation for PADEP’s methodology 

for determining the proposed RACT 

level of controls for each facility.9 For 

each unit at each facility, PADEP states 

that it followed a ‘‘top-down’’ approach 

to determine NOX emissions limits, 

which included searching for and 

identifying the ‘‘best methodology, 

technique, technology, or other means 

for reducing NOX while factoring 

environmental, energy and economic 

considerations into the analysis.’’ Con 

TEM, p. 2; Key TEM, p. 2; HC TEM, p. 

2. This included identifying the controls 

installed on coal-fired units in some 

other states. PADEP then used the EPA 

Control Cost Manual (sixth edition), 

June 12, 2019, and sometimes vendor’s 

quotes, to determine whether control 

options PADEP identified as technically 

feasible were also cost effective. Con 

TEM, pp. 2–3; Key TEM, p. 2; HC TEM, 

p. 3. PADEP performed some type of 

analysis for multiple NOX control 

technologies 10 for each facility before 

‘‘determin[ing] that no additional 

controls are cost effective.’’ Con TEM at 

3. See, e.g., Con TEM pp. 3–19. In lieu 

of new controls, PADEP determined that 

for each of the three facilities, changes 

to the way the facilities operated their 

SCRs and changes to how they ‘‘tuned’’ 

the boilers were the only technically 

available and cost-effective controls for 

reducing NOX emissions. Con TEM, pp. 

2–3; Key TEM, pp. 2–3; HC TEM, pp. 

2–3. This approach resulted in PADEP 

adopting three separate but related 

limits for each EGU at each of the three 

facilities. The proposed and final rates 

are in Table 1 of this document. The 

method that PADEP used to arrive at 

each of the three rates is summarized 

below. 

Selection of SCR-on lb/MMBtu Daily 

Average Rates 

To determine the ‘‘SCR-on’’ limit 

representing RACT for when the SCRs 

are operating, PADEP ‘‘analyzed daily 

NOX emissions rates from EPA’s Clean 

Air Markets Division (CAMD) database 

at varying operating load conditions’’ 

for most of the units at each facility. Con 

TEM, p. 3; HC TEM pp. 4–13; Key TEM 

p. 3. PADEP examined data for each 

facility ranging from 2016 to 2020, 

depending on the facility.11 For certain 

months within the 2016–2020 time 

frame, PADEP states that it analyzed the 

percentage of daily heat input and 

corresponding percentage of daily 

reagent injection for a unit or units at 

each facility to ascertain how heat input 

and reagent input affected daily NOX

emissions, and to determine the lowest 

emission limit each unit could 

technically and economically achieve 

with the SCRs. PADEP’s analysis 

included examining the percentage of 

maximum heat rate input for the unit for 

each day of certain months and the 

corresponding percentage of maximum 

ammonia (the reagent used) input 

observed per day for the same month. 

Con TEM, p. 4; Key TEM, pp. 3–8; HC 

TEM pp. 4–13. From this data, PADEP 

identified a ‘‘load’’ or heat input level 

at which it seemed that Conemaugh 

stopped injecting ammonia into the flue 

gas stream, see Con. TEM, p. 6, but did 

not identify loads or heat inputs at 

which Homer City’s or Keystone’s units 

stopped injecting ammonia. See HC 

TEM pp. 4–13, Key TEM pp. 3–8. 

PADEP also presented NOX emission 

rate data for certain months for each 

source during various ozone seasons, 

and for some periods outside of ozone 

seasons.12 For each facility, PADEP 

found that the automated controls that 

run the SCRs seemed to be set at an 

emissions ‘‘set point,’’ expressed as 

pounds of NOX per million Btus of heat 

input (lb NOX/MMBtu), and that these 

set points varied over time.13 For 

Conemaugh, PADEP concluded that 

‘‘additional emission reductions would 

be achieved if the operator operated the 

SCR with a lower emissions setpoint 

while the SCR is running.’’ Con. TEM, 

p. 6. For Keystone, PADEP stated 

‘‘[b]oth units at Keystone seem to be 

able to achieve a NOX rate of 0.060 lb/ 

MMBtu on a daily average basis,’’ but 

cited ‘‘varying load conditions and other 

factors’’ as affecting SCR performance 

and therefore proposed (and finalized) a 

daily average SCR-on rate of 0.08 lb/ 

MMBtu for both. Key TEM, p. 6. PADEP 

does not provide further information on 

what these other factors are or what 

impact they and load conditions would 

have that lead to the selection of the 

0.08 lb/MMBtu limit. For Homer City 

units 1 and 2, PADEP’s analysis 

concluded that the facility seemed to be 

targeting a NOX emission rate of 0.10 lb/ 

MMBtu when the SCRs were operating, 

but identified ‘‘rare’’ periods where the 

units achieved rates below 0.05 lb/ 

MMBtu. HC TEM, p. 5. However, 

PADEP concluded that ‘‘[d]espite the 

fact that emissions under 0.10 lb/ 

MMBtu are possible under at least some 

operating conditions, accounting for 

other operating condition requires a 

limit above the minimum achievable.’’ 

HC TEM, p. 8. PADEP therefore 

proposed (and finalized) a 0.080 lb/ 

MMBtu daily average operating rate for 

Units 1 and 2 when the SCR is 

operating. For Unit 3, PADEP found that 

it was also targeting a NOX emission rate 

of 0.10 lb/MMBtu, but during July 2019 

was able to consistently achieve NOX

rates between 0.08 and 0.09 lb/MMBtu 

despite daily load swings. HC TEM, p. 

9–10. PADEP identified two other 

instances where Unit 3 was capable of 

achieving NOX rates lower than 0.08, 

but did not identify the lowest 

achievable SCR-on rate before 

determining that other factors require a 

limit above the lowest achievable NOX

rate.14 Without identifying the lowest 

achievable NOX emission rate or 

explaining how the other factors affect 

that rate, PADEP proposed (and 

finalized) a rate of 0.07 lb/MMBtu when 

the SCR is operating. HC TEM, pp. 12– 

13. 

Certain changes made to PADEP’s 

proposed rates for each source in 

response to comments received are 

discussed in EPA’s analysis of the final 

rates. 


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15The Conemaugh TEM does not show the results 

of the full analysis of the 2017–2020 data. For 

example, Figure 6 in the Con TEM shows only 

ozone season operating load versus 30-day rolling 

average NOX emissions on a lb/hr basis for the 2017 

ozone season. Con TEM, p. 6. 

Selection of All Conditions lb/MMBtu 

Daily Average Rate 

The lb/MMBtu limits in the ‘‘All 

Conditions lb/MMBtu Daily Average’’ 

columns of Table 1 in this document, 

represent the daily average NOX limits 

that PADEP determined each unit at 

each facility could achieve solely 

through the operation of its existing 

low-NOX burners with overfire air, so 

long as the sources ‘‘tuned’’ their boilers 

to optimize the reduction of NOX rather 

than to obtain the highest heat output. 

PADEP describes boiler tuning as 

making a number of adjustments to the 

boiler operating parameters that affect 

the generation of NOX in the boiler fire 

box, including excess air levels, 

secondary air biasing, fuel/auxiliary air 

damper adjustments, burner tilt, fuel 

flow biasing, and changes to primary air 

flows. See, e.g., Con. TEM, pp. 14–15. 

As stated in the technical evaluation 

memo for Conemaugh, ‘‘[g]enerally 

boiler’s regular inspection, preventive 

maintenance, tuning, practicing during 

shutdown and upset conditions to 

prevent excess emissions, inspections 

and testing of Over Fire Air (OFA) 

components, and adjusted of burner 

angle to minimize NOX emissions 

results in lowering NOX emissions by 5– 

15% or at an average of 10. %. [sic]’’ 

Con. TEM, p. 15. For each of the EGU 

boilers (units) at each of the facilities, 

PADEP determined that the boiler 

burners had not been tuned to minimize 

NOX emissions, but rather had been 

tuned to maximize output. Key TEM, p. 

13; HC TEM, p. 15; Con TEM, pp. 14– 

15. For each facility, PADEP concluded 

that tuning the boilers to minimize NOX

emissions could result in lowering NOX

emissions by 5% to 15%, so PADEP 

elected to apply an average NOX

reduction of 10% when setting the ‘‘All 

Conditions lb/MMBtu Daily Average’’ 

rate. Id. 

Selection of All Conditions 30-Day 

Rolling Average lb/hr Rate 

Regarding the 30-day rolling average 

pounds of NOX/hour limits in the 

column in Table 1 labeled ‘‘All 

Conditions lb/hr 30-day Average,’’ there 

is some ambiguity in how PADEP 

arrived at the final rates for Keystone 

and Conemaugh. In the Keystone RTC, 

PADEP states the 30-day lb/hr limit was 

‘‘derived from the emission level at 0.08 

lb/MMBTU at full load . . . with an 

additional small margin to account for 

the fact that it is impossible to 

completely avoid all periods of 

operation when complying with the 

0.080 lb/MMBtu is technically 

infeasible.’’ Key RTC, p. 10. Similar 

language stating that the 30-day lb/hr 

rate was derived from the daily SCR-on 

rates is also in Con RTC p. 11 and HC 

RTC p. 9. PADEP’s explanation for how 

the 30-day lb/hr limits were derived in 

the Technical Evaluation Memos is 

more ambiguous and does not explicitly 

state the 30-day lb/hr rate is derived 

from the daily SCR-on lb/MMBtu rate. A 

description of what PADEP did in the 

Technical Evaluation Memos is outlined 

below. 

PADEP seems to have generally 

performed a similar analysis of similar 

years of data for all three facilities, but 

used a different method to set the 30- 

day lb/hr rates for Conemaugh and 

Homer City than for Keystone. For each 

source at each facility, PADEP says it 

analyzed ‘‘mass-based NOX emission 

rate in pounds per hour on a 30 

operational day rolling average basis 

using EPA’s CAMD database at all 

operating conditions for [the units] from 

2017–2020. Mass based emission rate on 

a 30 operational day rolling average 

basis is dependent on number of hours 

a unit is operated, on average, at high 

load vs low load for the past 30-days 

[sic].’’ 15 Con TEM p. 15; see also Key 

TEM pp. 13–14, HC TEM pp. 17–19. 

Following this analysis for each 

facility, for Conemaugh and Homer City 

PADEP used the SCR-on lb/MMBtu rate 

for each unit at each facility, then 

multiplied that SCR-on rate by each 

unit’s maximum MMBtu per hour rating 

to arrive at the number of pounds per 

hour that each unit would emit if they 

ran at their full heat input rating while 

complying with that unit’s SCR-on lb/ 

MMBtu rate. For example, the technical 

review memo for Conemaugh explains 

that: 

‘‘Each of Conemaugh’s units emits about 

580 lb NOX per hour assuming an emission 

level of .070 lb/MMBtu and 100% load. The 

impact to the environment should never 

exceed this level on a long-term basis. The 

Department is proposing a limit of 700 lb/hr 

limit on a 30 operational day rolling basis 

which accounts for all operating scenarios 

including situations during which the SCR is 

not able to operate. The compliance buffer 

also accounts for the fact that both units at 

Conemaugh operate as much as 10% over 

their rated capacity.’’ (Con TEM, p.15). 

For Conemaugh, PADEP concluded 

that Units 1 and 2 were operating 

between 55% and 100% load during 

this time and both were able to achieve 

at or below 625 lb/hr on a 30-operating 

day basis. PADEP found that during this 

time period both units operated at 

around a 0.075 lb/MMBtu NOX

emissions rate, with occasional higher 

spikes in rate. Based on this data, 

PADEP concluded: 

‘‘Given that the Department believes that 

NOX rates below .07 are readily achievable 

with the SCR in operation, and the fact that 

both units were able to achieve a 30-day 

rolling NOX rate of under 625 lb/hr despite 

operating at a rate between .075 and .1, DEP 

believes that Conemaugh Generating Station 

can achieve a NOX rate of 700 lb/hr on a 30- 

day rolling basis. Even if the facility were to 

operate at low load for a significant time 

during a 30-day averaging period—generating 

significantly more mass emissions than 

operation at higher loads with SCR, emission 

rates at high load should be significantly 

below 700 lb/hr allowing the facility to 

‘‘make up’’ for higher emissions during times 

of low load, assuming the facility operates to 

the NOX rate of .045–.05 lb/MMBtu it is 

usually capable of meeting when the SCR is 

operating.’’ Con TEM, pp. 16–17. 

Thus, for Conemaugh, PADEP proposed 

and finalized an all conditions 30-day 

rolling average lb/hr limit of 700 lb/hr. 

For Homer City, PADEP used the 

proposed SCR-on daily average NOX

limit of 0.08 lb/MMBtu for Units 1 and 

2, multiplied by the maximum MMBtu 

per hour for each of these units, to 

arrive at a 30-day rolling average limit 

of 550 lb of NOX per hour for each unit. 

For Unit 3, PADEP used the proposed 

SCR-on lb/hr daily average limit of 0.07 

lb/MMBtu multiplied by the maximum 

heat input for Unit 3 to arrive at a 

rolling 30-day average limit of 510 lbs 

of NOX per hour. HC TEM, p. 17. In 

response to a comment from Homer 

City, PADEP raised the 30-day rolling 

average lb/hr limits to 600 lb/hr for 

Units 1 and 2 and 560 lb/hr for unit 3. 

For Keystone, PADEP appears to have 

arrived at its proposed and final 30-day 

rolling average lb/hr limit through a 

different method. PADEP’s TEM states 

that PADEP analyzed the mass-based 

NOX emission rate pounds per hour on 

a 30-day rolling average at all operating 

conditions for Units 1 and 2 from 2017– 

2020. Key TEM, p. 13. The TEM then 

provides Figure 5, which graphs the 30- 

day rolling NOX rates for Units 1 and 2, 

but only for the 2017 ozone season. Key 

TEM. P. 14. From Figure 5, the TEM 

concludes that both units were able to 

achieve at or below 800 lbs/hr on a 30- 

day rolling average basis, continuously. 

Key TEM, p.14. The TEM then asserts 

that based on the CAMD data, ‘‘DEP 

believes that by managing combination 

of hours of operations when a unit is 

operating at loads supporting SCR and 

at lower loads with [low NOX burners], 

Unit 1 and Unit 2 can achieve 800 lbs/ 

hr on a 30-day operating day rolling 

average basis despite the changes in 

utilization of the boiler.’’ Id. From this, 


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16Nearly identical statements are in Key RTC p. 

6 and HC RTC p. 6. 

17 In Key RTC p. 10 PADEP states the 30-day lb/ 

hr limit was ‘‘derived from the emission level at 

0.08 lb/MMBTU at full load . . . with an additional 

small margin . . .’’ Similar language stating that the 

30-day lb/hr rate was derived from the daily SCRon rates is also in Con RTC p. 11 and HC RTC p. 

9. PADEP’s explanation for how the 30-day lb/hr 

limits were derived in Key TEM pp. 13–14, Con 

TEMP pp. 15–17 and HC TEM pp. 17–19 is more 

ambiguous and doesn’t explicitly state the 30-day 

lb/hr rate is derived from the daily SCR-on lb/ 

MMBtu rate as noted under the ‘‘Selection of All 

Conditions 30-day Rolling Average lbs/hr Rate’’ 

heading in section II. 

18PJM is the Pennsylvania-New Jersey-Maryland 

Interconnection, a regional transmission 

organization operating in the midatlantic states. 19COMAR is the Code of Maryland Regulations. 

PADEP concluded that the 800 lb/hr 30- 

day rolling average limit under all 

operating conditions is RACT. Id. 

However, in response to comments, this 

limit was changed to 770 lbs/hr for both 

units. Key RTC pp. 6. 

In the response to comments 

document for Conemaugh, PADEP 

explained that the 30-day rolling 

average lbs/hr all conditions rate ‘‘. . . 

is the glue that holds the three emission 

limits together and ensures that the 

emission reductions from the two 

Conemaugh Generating Station units are 

maximized . . . This emission limit 

applies at all times and in all 

circumstances, without exception.’’ Con 

RTC, p. 6. 16 PADEP further asserts that 

the SCR-on lb/MMBtu daily average rate 

minimizes the emissions that occur 

when operating with the SCR, while 

also claiming that the 30-day rolling 

average lb/hr all conditions rate 

minimizes ‘‘both the amount of time 

that the units can be operated when the 

SCR is technically unavailable, as well 

as forces the load (and therefore mass 

emission rate) to the lowest rate possible 

when it is not being operated due to 

technical unavailability.’’ See, e.g. Con 

RTC, p. 6. The RTC further explains that 

‘‘[a]t any load above approximately 

30%–40%, operation without control by 

the SCR results in emissions greater 

than 700 lbs/hr. As the load climbs, the 

emissions per hour climb 

proportionately.’’ Id. PADEP asserts that 

the 700 lb/hr rolling 30-day average 

limit ‘‘ensures that the operator will 

maximize operating hours with the SCR 

and minimize heat input (and total mass 

emissions) when operation of the SCR is 

technically infeasible.’’ Id. 

III. EPA’s Evaluation of the RACT 

Permit Limits in the SIP Submittals 

EPA’s review of the RACT permit 

limits in each of the three case-by-case 

RACT permits submitted as SIP 

revisions by PADEP has identified 

several issues appearing in each permit 

which preclude approval of the SIP 

submissions as satisfying RACT 

requirements. In summary, EPA has 

determined that there are issues 

regarding the enforceability of the SCRon permit limits, Director’s discretion 

issues related to the SCR-on limits, and 

an inadequate justification for why the 

SCR-on limits meet the definition of 

RACT for each source. Moreover, 

because some of the 30-day rolling 

hourly average pound per hour mass 

limits appear to be derived from the 

daily lb/MMBtu SCR-on limits, the 

failure of the SCR-on limit to meet the 

criteria for RACT calls into question 

whether the 30-day limits are RACT.17

Also, EPA cannot verify from PADEP’s 

submitted SIPs whether these 30-day 

rolling average pound per hour mass 

limits actually act as a constraint on 

operation of the EGUs without operation 

of the SCRs in a way that represents 

RACT. In addition, PADEP has added a 

‘‘compliance margin’’ buffer to the 30- 

day rolling average pound per hour 

limits without an adequate explanation 

of why that buffer is necessary to make 

the limits technologically or 

economically feasible. Each of these 

issues is discussed below. As a result, 

EPA is proposing to disapprove this SIP 

revision. 

Lack of Enforceability of the ‘‘SCR-On’’ 

Limits for Each EGU at Each Facility 

Neither the permits nor the 

background information submitted with 

the SIP set forth clear, objective criteria 

for determining when emissions from 

each EGU are subject to the SCR-on lb/ 

MMBtu daily average limit(s). As such, 

it is not possible in all circumstances for 

EPA or the public to determine whether 

this limit applies, and therefore whether 

the sources are in noncompliance with 

that limit. As a result, EPA is proposing 

to disapprove the PADEP SIP revision 

on this basis. 

Each permit includes language stating 

the NOX emissions are limited at a 

certain level, but that certain emissions 

are excluded when evaluating whether 

the limitations are met. Specifically, the 

permits contain exclusions for: 

‘‘. . . emissions during start-up, and shutdown; operation pursuant to emergency 

generation required by PJM, including any 

necessary testing for such emergency 

operations; and during periods in which 

compliance with this emission limit would 

require operation of any equipment in a 

manner inconsistent with technological 

limitations, good engineering and 

maintenance practices, and/or good air 

pollution control practices for minimizing 

emissions.’’ See, e.g., Conemaugh final 

permit, Section E, Restrictions, #001, p. 176. 

Keystone Final Permit, p. 169, and Homer 

City Final Permit p. 134.18

EPA has determined that the 

exclusion during ‘‘Operation pursuant 

to emergency generation required by 

PJM’’ is problematic. This condition is 

not defined in the permit for Homer City 

but is defined in the final permits for 

Conemaugh (p. 176) and Keystone 

(p.169), stating that ‘‘the emissions limit 

remains in effect unless the permittee 

demonstrates that compliance with the 

[applicable emission limitation] is 

technically infeasible.’’ There are no 

bounds or explanation in the permit 

regarding what would equate to 

technical infeasibility, nor is there 

information on whom the permittee 

would demonstrate this infeasibility to 

or how EPA or the public could 

determine whether such an adequate 

demonstration was made. In response to 

comments, PADEP stated: 

‘‘the Conemaugh Station permit includes a 

process where emissions can be requested for 

exclusion from calculation of the 0.070 lb/ 

MMBtu emission limit if the owner/operator 

makes a demonstration of technical 

infeasibility to the Department’s satisfaction. 

The general factors that may lead to technical 

infeasibility are included in the Conemaugh 

Station permit, and mirror SIP-approved 

RACT regulations in neighboring states. In 

fact, the list of general factors in 

Conemaugh’s permit is more limited than the 

factors listed in regulations promulgated by 

one commentator. See COMAR 26.11.38.04 

section 4.’’ 19 Con RTC, p. 3. 

EPA did not find the suggested list of 

‘‘general factors’’ which may lead to a 

determination of technical infeasibility. 

EPA also notes that this type of posthoc determination allowing the director 

to grant exemptions from a SIPapproved emission limit during periods 

of startup, shutdown or other periods is 

the type of director’s discretion 

prohibited by the CAA, for the reasons 

set forth in EPA’s 2015 startup, 

shutdown and malfunction (SSM) SIP 

Action. 80 FR at 33840, 33917 (June 12, 

2015). As stated in the 2015 SSM SIP 

Action, ‘‘SIP provisions cannot contain 

director’s discretion to alter SIP 

requirements, including those that allow 

for variances or outright exemptions for 

emissions during SSM events.’’ 80 FR at 

33917. In the case of the permits 

submitted as part of Pennsylvania’s 

2022 SIP revision, each contains 

language that allows the director to 

decide whether or not emissions from a 

source during any hour should be 

counted towards the more stringent 

SCR-on emission limits of 0.07–0.08 lb/ 

MMBTU or to the less stringent 

emission limits of 0.27–0.45 lb/ 

MMBTU. Although the rates would not 

change, the director would be making a 


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20See the final document at 82 FR 24546 (May 

30, 2017) approving the NOX limits for Maryland’s 

EGUs as SIP strengthening measures, and the final 

document at 84 FR 5004 (February 20, 2019) 

approving Maryland’s RACT regulations for 

controlling VOC major sources for the 2008 ozone 

NAAQS, which notes that Maryland will address 

major sources of NOX in another SIP. None of the 

VOC regulations approved included the language in 

COMAR 26.11.38.04. 

21Conemaugh final permit, p. 177. The final 

unredacted permits for all three facilities also state 

that the monthly reports should include the hourly 

load levels, heat input, ammonia injection rates, 

NOX rates, total NOX emissions, the SCR emission 

set point, SCR inlet and outlet temperature, and 

clearly indicate any days which the SCR-on lb/ 

MMBtu emission limit is exceeded. For days 

exceeding the SCR-on lb/MMBtu limit, the above 

information must be provided on an hourly basis 

and the permittee must give a detailed explanation 

for why they exceeded their emission limit. 

Conemaugh permit, p. 176, Keystone permit pp. 

170–171, Homer City permit p. 137. 

22 ‘‘State Implementation Plans: Response to 

Petition for Rulemaking; Restatement and Update of 

EPA’s SSM Policy Applicable to SIPs; Findings of 

Substantial Inadequacy; and SIP Calls To Amend 

Provisions Applying to Excess Emissions During 

Periods of Startup, Shutdown and Malfunction’’ 80 

FR 33840, section XI.D. 

23 Ibid. P 33913. 

24 Ibid. p. 33914. 

25EPA also notes an inconsistency in how PADEP 

discusses the data that was considered in 

developing the limits at issue in this SIP revision. 

In the RTCs, PADEP references data from 2016– 

2020. (Key RTC p. 8, Con RTC p. 9, and HC RTC 

p. 7). However, in the TEMs, PADEP references data 

from 2017–2020. 

decision as to whether certain emissions 

should be exempted from the more 

stringent SCR-on lb/MMBtu 24-hour 

average rate. This is the type of 

unilateral, ad hoc (or post hoc) decision 

by the director which could negate the 

possibility of enforcement of an 

otherwise enforceable SIP emission 

limit by EPA or the public and which 

is barred by EPA as first established in 

the 1999 SSM Guidance. 1999 SSM SIP 

guidance at 3, 80 FR 33840 at 33917. 

In addition, pursuant to EPA’s 

responsibilities under sections 

110(k)(3), 110(l) and 193 of the CAA, the 

Agency cannot approve a SIP provision 

that automatically preauthorizes the 

state to unilaterally revise the SIP 

emission limit (in this case by making 

determinations that it did not apply at 

certain times) without meeting the 

applicable procedural and substantive 

statutory requirements for SIP revisions. 

80 FR at 33918. As stated in EPA’s 2015 

SSM SIP Action, ‘‘[i]t is a fundamental 

tenet of the CAA that states cannot 

unilaterally change SIP provisions, 

including the emission limitations 

within SIP provisions, without the 

EPA’s approval of the change through 

the appropriate process.’’ Id. 

In the quoted response to comments 

on this issue, PADEP claims that the list 

of general factors in the permits (which 

EPA could not locate) are more limited 

than factors listed in Maryland’s 

regulations. EPA notes that it has not 

approved the cited Maryland regulation, 

COMAR 26.11.38.04, as RACT for EGUs, 

so the cited example does not carry any 

weight in EPA’s analysis of this SIP 

revision.20 PADEP claims that the list of 

general factors (which again, EPA could 

not locate) ‘‘mirror SIP-approved RACT 

regulations in neighboring states,’’ but 

PADEP does not identify these other 

SIP-approved RACT regulations and 

EPA is not aware of what PADEP may 

be referencing. Without knowing which 

SIP-approved RACT regulations PADEP 

is referring to, EPA cannot judge the 

relevance of this argument. 

The exclusion for ‘‘periods in which 

compliance with this emission limit 

would require operation of any 

equipment in a manner inconsistent 

with technological limitations, good 

engineering practices, and/or good air 

pollution control practices . . .’’ is also 

problematic. No permit provides 

additional definitions or instruction on 

how this provision should be 

interpreted or applied. Similar to other 

provisions at issue here, this lack of 

definition makes this exemption 

provision difficult or impossible to 

enforce. 

Although the permits require that the 

sources keep certain data and submit a 

monthly report to PADEP, it is in the 

sources’ discretion to identify in these 

monthly reports ‘‘whether or not they 

believe they are subject to the [SCR-on] 

lb NOX/MMBtu limit’’ and ‘‘clearly 

document how [they] determined 

whether or not they believe they are 

subject to the [SCR-on] lb NOX/MMBtu 

hourly limit.’’ 21 But this does not 

explain how PADEP will determine 

whether certain hours of NOX emissions 

from the sources should be counted 

towards the SCR-on daily average lb/ 

MMBtu limits for each source, or the 

circumstances under which these 

emissions would be excluded from the 

limit. It is even more difficult to 

understand how EPA or the public 

would discern which hours of emissions 

should be counted towards the SCR-on 

limit. If it is unknown which hours of 

emissions count, it is impossible to 

determine whether a source complied 

with the SCR-on limit. In other words, 

without clear and objective criteria for 

excluding these emissions, neither EPA 

nor the public could determine whether 

the sources were complying with the 

SCR-on limit at each source. Although 

this situation is somewhat different than 

the situation faced by the Third Circuit 

in the Sierra Club appeal (lack of 

adequate recordkeeping), the lack of 

objective criteria for determining 

compliance in this situation leads to the 

same problem identified by that court, 

which is that there is no way for 

interested members of the public or EPA 

to conduct oversight. Sierra Club at 307. 

Pennsylvania’s Inadequate Justification 

of Certain Limits as RACT 

EPA understands the PADEP’s 

submission to argue that RACT for these 

facilities is comprised of: (1) a low daily 

SCR-on lb/MMBtu limit with exclusions 

as outlined in the prior section; (2) a 

much higher all conditions daily lb/ 

MMBtu limit that provides a 

permissible emissions level under all 

operating conditions including when 

the SCR is not operating; and (3) the 30- 

day rolling average all conditions lb/hr 

limit, which is intended to provide 

some restriction on the extent to which 

the source could claim exclusions from 

the SCR-on rate. EPA has identified 

issues with each of these limits as 

discussed in the subsections below. EPA 

does allow for the possibility that 

different or alternative emissions limits 

(AELs) can apply during different 

modes of operation in the manner that 

PADEP has done here for the three 

different limits described.22 However, 

EPA has stated that those AELs ‘‘must 

be clearly stated components of the 

emission limitation, must meet the 

applicable level of control required for 

the type of SIP provision (e.g., be RACT 

for sources located in nonattainment 

areas) and must be legally and 

practicably enforceable.’’ 23

Accordingly, here EPA must evaluate 

whether this combination of limits 

satisfies the OTR RACT requirement. 

PADEP did not provide any justification 

for why these limits appropriately 

function as alternative emission limits. 

In the 2015 SSM SIP Action, EPA 

recommended states consider seven 

criteria when developing alternative 

emission limits.24 These recommended 

criteria assure the alternative emission 

limitations meet basic CAA 

requirements. PADEP did not explain 

why the alternative emission limitations 

included in this SIP revision meet CAA 

requirements, including RACT, and EPA 

cannot approve alternative emission 

limitations without such a showing. 

Further, PADEP developed the 

emissions limits for the Keystone, 

Conemaugh and Homer City Facilities 

by reviewing only operating data and 

emissions rates from a limited number 

of years.25 PADEP claims that using 

emissions and operating data from a 

limited set of relatively recent years is 

justified because these years reflect 

what is currently possible due to aging 


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26 In response to a comment submitted on 

Conemaugh, PADEP replied that during the 2018 

ozone season, with a few exceptions, Conemaugh’s 

unit 2 was consistently able to achieve daily 

emission levels in the .055–.07 lb NOX/MMBtu 

range. Con. RTC, p. 7. 

equipment and changes in operating 

patterns, including the impact of 

changes made to the catalyst in the SCR 

system in order to meet the 

requirements of the 2011 Mercury Air 

Toxics Standard (MATS) (Key RTC p. 8, 

Con RTC p. 9, and HC RTC p. 7). 

However, PADEP presented no data or 

analysis showing that aging equipment, 

particularly the SCR control systems, 

have deteriorated such that data from 

earlier years are unreliable. PADEP’s 

submittals have also not justified a rate 

selection methodology that relies on a 

limited set of years, nor have they 

explained why the selected years 

represent the lowest rate that can now 

be achieved when accounting for such 

changes. Stated differently, the RACT 

limits (regardless of averaging time) 

must reflect levels that represent 

periods of good emissions control, not 

business as usual (e.g., a 5-year average 

of past results) or higher-emitting 

periods. 

Selection of the SCR-On lb/MMBtu Daily 

Average Emission Rates 

PADEP’s own data and analysis calls 

into question whether the final SCR-on 

daily average lb/MMBtu rates for 

Conemaugh (0.070 lb/MMBtu), 

Keystone (0.080 lb/MMBtu) and Homer 

City (0.080 lb/MMBtu for Units 1 and 2, 

and 0.070 lb/MMBtu for Unit 3) are 

RACT. Based on PADEP’s SIP 

submission, EPA cannot determine 

whether the SCR-on rates for any of the 

three facilities are the lowest rates that 

can be achieved considering 

technological and economic feasibility. 

Although PADEP makes a general 

determination that optimization of the 

existing SCRs at each facility is RACT, 

the data PADEP provided in its SIP 

submission do not support a claim that 

these rates are the lowest achievable 

rates that can reasonably be obtained at 

each unit when the SCRs are operating, 

considering technological and economic 

feasibility. In addition, PADEP then 

applies an upward adjustment to these 

rates to account for factors, such as lag 

time, changes in boiler operating 

patterns, and aging of equipment, that 

PADEP states it has already accounted 

for by using data from 2017 to 2020 in 

their analyses for setting the RACT 

limits. As such, there should be no 

needed upward adjustment to account 

for these factors. Also, PADEP 

consistently applies a compliance 

margin to its rates without explaining 

what the margin is, in many cases, or 

why such a margin is needed to make 

the selected limit technologically or 

economically feasible. 

Conemaugh 

For Conemaugh, PADEP asserts that it 

examined CAMD emissions and other 

data for Units 1 and 2 for the years 

2017–2020, but because both units are 

similar, assumed that data from unit 1 

applied to unit 2 and therefore only 

discussed unit 1 data.26 Con TEM, pp. 

3–4. Figure 1 in the TEM is a graph 

showing percentage of heat input, NOX

emission rates and percentage of 

ammonia injection rates during May 

2017. From this graph, PADEP 

determined that Conemaugh Unit 1 

maintained a NOX emission rate of 

0.045 lb/MMBtu from May 5th through 

May 18th, which PADEP attributed to 

an ammonia injection control system 

operating at a set point of 0.045 lb/ 

MMBtu. Con TEM, p. 4. From May 19th 

through the end of May 2017, PADEP 

observed that the ‘‘relative difference 

between the ammonia injection rates 

and heat input rates have increased,’’ 

leading to a steady NOX emission rate 

around 0.08 lb/MMBtu. Id. PADEP then 

notes that following May 2017, unit 1 

only operated with varying set points 

between 0.065 and 0.08 lb/MMBtu 

throughout the 2017 and 2018 ozone 

seasons. Con TEM, p. 5. PADEP further 

observed that NOX rates increased 

significantly in 2019 and provided a 

graph (Figure 2) which PADEP asserts 

shows that during this month, 

Conemaugh ceased injecting ammonia 

for NOX control at around 50% heat 

input, and even when operating at 

100% of heat input, the NOX emission 

rates stayed around 0.1 lb/MMBtu. 

PADEP concluded that ‘‘this strongly 

suggests that additional emission 

reductions would be achieved if the 

operator operated the SCR with a lower 

emission set point while the SCR is 

running.’’ Con TEM, p. 6. In addition, 

PADEP identified an April 2020 

example when the SCR was not 

operating despite the boiler operating at 

loads ‘‘clearly supporting’’ SCR 

operation, with NOX emissions close to 

0.3 lb/MMBtu during this time. Con 

TEM, p. 7. From this PADEP concluded 

that ‘‘[s]imply choosing not to operate 

the SCR is not indicative of the control 

level achievable by the system.’’ Id. 

Based on this data, PADEP then selected 

an SCR-on rate of 0.07 lb/MMBtu for 

Conemaugh. Id. The only explanation 

given for this specific rate is that it 

‘‘includes a factor to provide an 

appropriate compliance margin, 

fluctuations in load, any lag in the 

control system as well as to account for 

other factors in the facility’s future 

operations.’’ Con TEM, p. 8. 

The response to comments (RTC) 

document for Conemaugh adds 

discussion of a 2017 study performed on 

unit 1 in May 2017 that suggested that 

running the SCR with a set point of 0.04 

lb/MMBtu caused a spike in mercury 

emissions, and also discusses a 2016 

study at the end of ozone season on unit 

2 that suggested running the SCR at a 

0.050 lb/MMBtu set point also caused 

an increase in mercury emissions. RTC, 

pp. 6–8. Based on further analysis, 

PADEP concluded that ‘‘a setpoint of 

0.06 lb NOX/MMBtu . . . is achievable 

by [Conemaugh].’’ RTC p. 8. However, 

the RTC states, without explanation, 

that PADEP is choosing to keep the 0.07 

lb NOX/MMBtu daily average emission 

rate. RTC p. 8. 

EPA finds that PADEP’s explanation 

of why this limit meets the definition of 

RACT is inadequate. Having concluded 

in the RTC that a 0.06 setpoint is 

achievable at Conemaugh, PADEP 

provides no explanation as to why it 

selected 0.07 lb/MMBtu as the daily 

average SCR-on rate. Nor is there any 

explanation of why a compliance 

margin is necessary, what compliance 

margin was applied in this instance, 

how fluctuations in load or lag in the 

control system affect the lowest 

achievable emissions rate, and how or 

why the rate must be adjusted to 

account for future operations. In the 

absence of an explanation of how 

PADEP selected the specific 0.07 lb/ 

MMBtu rate and how any of these other 

factors affect the technical and 

economic feasibility of the lowest rate 

identified, EPA cannot support PADEP’s 

conclusion that the 0.07 lb/MMBtu 

daily average rate is RACT for when 

Conemaugh’s SCRs are operating. 

Keystone 

Like Conemaugh, PADEP’s analysis 

for Keystone’s SCR-on daily average rate 

of 0.08 lb/MMBtu does not adequately 

explain why this rate represents the 

lowest emission limit that Keystone’s 

two units are capable of meeting based 

on technological and economic 

feasibility. In the TEM for Keystone, 

PADEP explains that it analyzed EPA’s 

CAMD data for Keystone Units 1 and 2 

from 2017–2020. Key TEM, p. 3. The 

TEM then includes a graph (Figure 1) 

showing certain daily operating 

statistics for unit 2 for the month of May 

2017, from which PADEP concludes 

that unit 2 was able to maintain a NOX

emission rate below 0.06 while the SCR 

was operating. TEM, p. 4. The TEM then 

shows a graph (Figure 2) plotting certain 


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27The final unredacted permit does not mention 

this setpoint study. Instead, Section E, Source 

Group Restrictions, subsection VI, Work Practice 

Requirements, condition #012 requires that 

Keystone submit a technical evaluation to PADEP 

on the possibility of heating the flue gas prior to the 

SCR inlet to allow SCR operation at low load levels. 

Keystone final permit, p. 172. This condition does 

not appear in the redacted final permit submitted 

for inclusion into the SIP. 

daily operating parameters for unit 1 

during May 2017. TEM, p. 5. From 

Figure 2, PADEP concludes that unit 1 

was able to achieve a 0.05 lb/MMBtu 

rate for ten days, but this rate increased 

to 0.09 lb/MMBtu for the rest of the 

month because the operator elected to 

inject less ammonia into the SCR system 

even though the heat input remained 

almost constant at levels supporting 

SCR operation. Key TEM, p. 5. From 

this and other data, PADEP concludes 

that both Keystone units can achieve an 

SCR-on rate of 0.06 lb/MMBtu on a 

daily average basis. 

The Keystone response to comments 

contains a long discussion of a study 

Keystone submitted at some point in 

time purporting to show the effects of 

trying to operate the SCRs at a NOx 

emission rate setpoint of 0.05 to 0.06 lb/ 

MMBtu during May 2017. Keystone 

RTC, p. 26. The RTC notes that when 

Unit 2 attempted to operate at 0.055 lb/ 

MMBtu for two months in 2017, 

pressure drop across the air preheater 

increased to a level requiring 

measures—in this case raising the SCR 

setpoint to 0.08 lb/MMBtu—to reduce 

the pressure drop. Id. at 27. The same 

study found that operating unit 1’s SCR 

at a 0.05 lb/MMBtu setpoint for only 15 

days resulted in SCR catalyst fouling 

which prevented the SCR from 

operating under 0.08 to 0.09 lb/MMBtu 

rates for the rest of the test period. Id. 

The Keystone RTC then discusses at 

length the meaning of the study and 

information submitted by another 

source and the effect of different SCR set 

points on pressure drop, catalyst 

fouling, and the ability to meet certain 

NOX emission rates. Key RTC, pp. 27– 

30. PADEP concluded from these 

studies that Keystone should conduct a 

future setpoint study to determine that 

optimal emission levels from the SCR 

are achieved, but that based on the 

current evidence, the SCR controls 

setpoint should be changed from 0.06 to 

0.07 lb NOX/MMBtu.27 Key RTC, p. 32. 

However, PADEP set a NOX emission 

rate of 0.08 lb/MMBtu because ‘‘varying 

load conditions and other factors can 

and do affect SCR performance and 

resulting NOX emission rates.’’ TEM, p. 

6. 

EPA acknowledges that catalyst 

fouling and other similar factors may 

affect the feasibility of SCR to achieve 

low rates. However, similar to EPA’s 

review of the Conemaugh limit, in the 

absence of an explanation of how any of 

these other factors affect the technical 

and economic feasibility of the lowest 

rate identified, EPA cannot support 

PADEP’s conclusion that the 0.08 lb/ 

MMBtu daily average rate represents 

RACT. 

Homer City 

Similar to EPA’s assessment of the 

rates for Conemaugh and Keystone, 

PADEP does not provide adequate 

justification for Homer City’s final SCRon daily average rates of 0.08 lb/MMBtu 

for units 1 and 2 and 0.07 lb/MMBtu for 

unit 3 are the lowest emission limit that 

these sources can meet based on 

technological and economic feasibility. 

The TEM for Homer City explains that 

PADEP evaluated data from 2017–2020 

for all three units. PADEP notes that the 

unit 1 and 2 SCRs were upgraded in 

2018, and ‘‘NOX emission rates 

significantly improved,’’ TEM, p. 6, but 

fails to explain why, in light of this, 

PADEP thought consideration of 2017 

data was appropriate. For units 1 and 2, 

PADEP notes that during 2019 and 2020 

the SCRs were operated to generally 

keep NOX emission rates at 0.10 lb/ 

MMBtu, but also identified periods of 

time when the NOX emission rate for 

unit 2 went as low as 0.05 lb/MMBtu 

because more ammonia was being 

injected. TEM, p. 5. The TEM states that 

other instances of between 0.05 and 0.10 

lb/MMBtu were identified. TEM, p. 5. 

Looking at additional data following the 

upgrade, PADEP suggested that ‘‘had 

July of 2020’s ammonia injection rates 

matched that of July 2019, significantly 

[sic] emissions reductions could have 

been achieved during that timeframe.’’ 

TEM p. 6. The TEM then states that 

‘‘[d]espite the evidence presented,’’ 

other factors such as load, exhaust 

temperature, etc., and other unspecified 

factors ‘‘can and do affect SCR 

performance’’ and require an operating 

limit above the never specified 

achievable minimum. TEM, p. 8. PADEP 

then selected an SCR-on rate of 0.08 lb/ 

MMBtu as a daily average for units 1 

and 2 but provided no analysis or 

explanation why 0.08 lb/MMBtu is the 

lowest rate that these units could meet 

based on technological and economic 

feasibility. See TEM, pp. 4–9. The TEM 

also states that the rate includes an 

unspecified factor to include a 

compliance margin, account for load 

fluctuations, control system lags, and 

projected future changes in operations. 

TEM, p. 9. In the RTC, PADEP seems to 

apply the ‘‘findings’’ from Keystone’s 

attempt to operate the SCRs with a low 

0.05 lb/MMBtu setpoint that such a 

setting leads to fouling of the air 

preheater, high pressure drops, and SCR 

catalyst fouling before determining that 

an emission rate of 0.08 lb/MMBtu will 

not cause these problems at Homer City. 

RTC, p. 11. 

For unit 3, the TEM states that there 

is evidence that unit 3 can meet a NOX

emission rate between 0.08 and 0.09 lb/ 

MMBtu, but limited evidence that it can 

meet a lower limit under certain 

circumstances. TEM, p.10. Citing the 

same factors affecting SCR performance 

as it cited for units 1 and 2, PADEP then 

concludes a value above the minimum 

SCR rate is needed, but without 

explanation sets the SCR-on daily 

average rate at 0.07 lb/MMBtu. TEM, p. 

13. In their response to comments 

document, PADEP seems to rely upon 

Keystone’s study of operating the SCRs 

at a low set point to support their 

selection of the SCR-on limits for all the 

units. However, there is no discussion 

of why the Keystone study can be 

applied to Homer City, particularly 

given that Homer City seems to use an 

economizer bypass to keep the SCRs 

operating at lower temperatures than 

might be possible at Keystone. 

Selection of the All Conditions 30-Day 

Rolling Average lb/hr Rate 

The PADEP permits allow significant 

emissions to be excluded from the daily 

lb/MMBtu SCR-on rate under a variety 

of conditions, and it is necessary to 

evaluate whether the alternative 

emissions limits applicable during these 

excluded conditions constitute RACT. 

Although the PADEP permits contain a 

daily lb/MMBtu no-SCR rate, PADEP 

suggests that the 30-day rolling average 

lb/hr rate is ‘‘the glue’’ that holds the 

emissions limits together, and EPA 

acknowledges that it is a critical 

component to the RACT justification 

because it establishes the practical 

limitation on the extent to which the 

source can operate without SCRs over 

an extended period of time. 

Accordingly, EPA must evaluate 

whether PADEP’s 30-day rolling average 

limit satisfies the RACT requirement. 

EPA’s assessment is that PADEP fails to 

clearly demonstrate that the All 

Conditions 30-day rolling average lb/hr 

rate necessitates that these facilities 

operate their SCRs to achieve the lowest 

emission rate that is technologically and 

economically feasible, which is required 

to meet the definitions of RACT. 

PADEP asserts that the 30-day rate 

represents RACT because ‘‘[a]t any load 

above approximately 30%–40%, 

operation without control by the SCR 

results in emissions greater than 700 

lbs/hr.’’ See, e.g., Con RTC p. 6. This 

suggests that the SCR would be 


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13030 Federal Register / Vol. 89, No. 35 / Wednesday, February 21, 2024 / Proposed Rules 

necessary at higher loads, but it does not 

address the question of whether it meets 

the RACT requirements when the 

facilities could run at 30–40% without 

using SCR. The EPA believes that it is 

possible that the sources could operate 

at low loads while simultaneously 

meeting the daily All Conditions lb/ 

MMBtu rate and the 30-day lb/hr rate, 

thereby creating a permissible way to 

avoid operating the SCR for long periods 

of time. This resembles the 600-degree 

temperature SCR ‘‘loophole,’’ which the 

Third Circuit was highly critical of, that 

allowed facilities to operate just below 

the temperature threshold at night when 

demand was low and to avoid running 

the SCR. Sierra Club, 306. The 30-day 

lb/hr all conditions rate does not appear 

to resolve this issue. 

Furthermore, PADEP’s justification 

for the All Conditions 30-day lb/hr rates 

leave many specifics about the 

justification of the selected rates 

unanswered. Each of PADEP’s technical 

evaluation memos have similar language 

stating ‘‘[PADEP] evaluated and 

analyzed mass-based NOX emission rate 

in pounds per hour on a 30-day rolling 

average basis from EPA’s Clean Air 

Markets Division (CAMD) database at all 

operating conditions . . . from 2017– 

2020.’’ PADEP then presents a set of 

graphs for each unit depicting the 30- 

day average rolling NOX emissions (lb/ 

hr) overlaid with percentage of 

maximum heat input (MMBtu). The 

time frames explored in these graphs is 

summarized in table 2 of this document. 

TABLE 2—TIME FRAMES FOR 30-DAY AVERAGE DATA PROVIDED BY PADEP 

Location in technical evaluation memo Facility Unit Time frame 

pg. 16, figure 6 ........................................ Conemaugh ....................... 1 May 2017–September 2017. 

pg. 16, figure 6 ........................................ Conemaugh ....................... 2 May 2017–September 2017. 

pg. 14, figure 5 ........................................ Keystone ............................ 1 May 2017–September 2017. 

pg. 14, figure 5 ........................................ Keystone ............................ 2 May 2017–September 2017. 

pg 18, Figure 11 ...................................... Homer City ........................ 1 January 2019–December 2021. 

pg 18, Figure 11 ...................................... Homer City ........................ 2 January 2019–December 2021. 

pg 18, Figure 11 ...................................... Homer City ........................ 3 January 2019–September 2020 (approximate). 

None of these graphs displays data for 

the full 2017–2020 timeframe PADEP 

evaluated and analyzed. Only the 

graphs from Homer City units display 

data for more than a single year. 

PADEP’s analysis then consists of a 

qualitative description of the 30-day lbs/ 

hr average the units were able to achieve 

in the time frames in table 2 of this 

document, but lacks data or description 

of what 30-day lb/hr all conditions rates 

were observed outside of those time 

frames. Without additional information 

about the 30-day average lb/hr rates 

achieved during the four years PADEP 

analyzed, EPA cannot determine 

whether the lb/hr limit selected for each 

unit represent an average of these years 

of data, which the Sierra Club court 

found problematic, or the lowest 

emissions in lb/hr which these sources 

achieved in this time frame, considering 

technological and economic feasibility. 

PADEP may or may not have 

reviewed a complete set of data from 

2017–2020, but the analysis of this was 

not included in the technical evaluation 

memos or the response to comment 

documents. As such, EPA could not 

determine whether or this 30-day all 

conditions lb/hr rate ‘‘. . . ensures that 

the operator will maximize operating 

hours with the SCR and minimize heat 

input (and total mass emissions) when 

operation of the SCR is technically 

infeasible.’’ 

Additionally, the compliance buffer 

added to the 30-day lb/hr all conditions 

rate does not appear to be sufficiently 

justified. PADEP states in its Technical 

Evaluation Memo for Conemaugh 

‘‘[e]ach of Conemaugh’s units emits 

about 580 lb NOX per hour assuming an 

emission level of .070 lb/MMBtu and 

100% load. The impact to the 

environment should never exceed this 

level on a long-term basis.’’ Con TEM p. 

15. It would appear PADEP arrived at 

this number simply by multiplying the 

daily SCR-on (lb/MMBtu) Rate by each 

boiler’s rated capacity (MMBtu/hr). 

Similar statements were made in the 

memos for Keystone and Homer City. 

See table 3 of this document, for this 

calculation for each boiler at Keystone, 

Conemaugh and Homer City. The table 

also compares this to the permit limits 

contained in PADEP’s 2022 SIP 

Submission, as well as a simple 

calculation of the percent increase in 

those limits (a compliance buffer added 

by PADEP). However, no explanation is 

given for why compliance buffers of 10– 

21% are needed, or why certain units 

should receive more than double the 

buffer of others. 

TABLE 3—COMPLIANCE BUFFERS FOR PADEP’S 30-DAY ALL CONDITIONS lb/hr RATES

Facility Unit 

Rated 

capacity 

(MMBtu/hr) 

Permit 

limit daily 

SCR-on 

(lb/MMBtu) 

Calculated at 

capacity 

(lb/hr) 

Permit limit 

30-day avg. 

(lb/hr) 

Compliance 

buffer 

(%) 

Conemaugh .............................................. 1 8,280 0.070 580 700 21 

2 8,280 0.070 580 700 21 

Keystone .................................................. 1 8,717 0.080 697 770 10 

2 8,717 0.080 697 770 10 

Homer City ............................................... 1 6,792 0.080 543 600 10 

2 6,792 0.080 543 600 10 

3 7,260 0.070 508 560 10 


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Federal Register / Vol. 89, No. 35 / Wednesday, February 21, 2024 / Proposed Rules 13031 

EPA Approval Would Not Be Consistent 

With CAA Section 110(l) 

Section 110(l) of the CAA prohibits 

the Administrator from approving any 

SIP revision ‘‘. . . if the revision would 

interfere with any applicable 

requirement concerning attainment and 

reasonable further progress (as defined 

in section 7501 of this title), or any 

other applicable requirement of this 

chapter.’’ For over 15 years, EPA has 

interpreted section 110(l) as permitting 

approval of a SIP revision as long as 

‘‘emissions in the air are not increased,’’ 

thereby preserving ‘‘status quo air 

quality.’’ Ky. Res. Council, Inc. v. EPA, 

467 F.3d 986, 991 (6th Cir. 2006); see 

also Indiana v. EPA, 796 F.3d 803, 806 

(7th Cir. 2015); Ala. Env’t Council v. 

EPA, 711 F.3d 1277, 1292–93 (11th Cir. 

2013); Galveston-Houston Ass’n for 

Smog Prevention v. EPA, 289 F. App’x 

745, 754 (5th Cir. 2008). This turns on 

EPA’s interpreting ‘‘interfere’’ as 

meaning ‘‘to hinder or make worse.’’ Ky. 

Res. Council, 467 F. 3d at 995. The court 

in a recent Third Circuit decision 

confirmed that a 110(l) analysis is not a 

one-size-fits-all provision and the 

variables that must be analyzed depend 

on the particular interference the SIP 

revision poses. Center for Biological 

Diversity v. EPA, 75 F.4th 174, 181 (3rd 

Cir. 2023). Here, with the information 

available to EPA, EPA could not 

determine that approval of the SIP 

revisions at issue would not result in 

interference. Therefore, EPA approval of 

these SIP revisions would not be 

consistent with section 110(l). 

IV. Proposed Action 

EPA’s review of these materials 

indicates that Pennsylvania’s May 2016 

SIP Submittals for Keystone, 

Conemaugh and Homer City Generating 

facilities: (1) do not adequately support 

Pennsylvania’s justification for the 

selection of RACT limits for the large 

EGU boilers; (2) lack enforceable 

objective clear criteria for determining 

when emissions from each EGU are 

subject to the SCR-on 24-hour average 

limit; and (3) contain unbounded 

director’s discretion provisions. For 

these, and other reasons described 

above, EPA is proposing to disapprove 

Pennsylvania’s May 26, 2022 SIP 

revisions. EPA is soliciting public 

comments on the issues discussed in 

this document. These comments will be 

considered before taking final action. 

V. Statutory and Executive Order 

Reviews 

Additional information about these 

statutes and Executive Orders can be 

found at https://www.epa.gov/lawsregulations/laws-and-executive-orders. 

A. Executive Order 12866: Regulatory 

Planning and Review and Executive 

Order 13563: Improving Regulation and 

Regulatory Review 

This action is not a ‘‘significant 

regulatory action’’ as defined by 

Executive Order 12866 and was 

therefore not submitted to the Office of 

Management and Budget for review. 

B. Paperwork Reduction Act (PRA) 

This proposed action does not impose 

an information collection burden under 

the PRA because it does not contain any 

information collection activities. 

C. Regulatory Flexibility Act (RFA) 

I certify that this action will not have 

a significant economic impact on a 

substantial number of small entities 

under the RFA. This action merely 

proposes to disapprove a SIP 

submission as not meeting the CAA. 

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. This action does not apply 

on any Indian reservation land, any 

other area where the EPA or an Indian 

tribe has demonstrated that a tribe has 

jurisdiction, or non-reservation areas of 

Indian country. Thus, Executive Order 

13175 does not apply to this action. 

G. Executive Order 13045: Protection of 

Children From Environmental Health 

Risks and Safety Risks 

The EPA interprets Executive Order 

13045 as applying only to those 

regulatory actions that concern 

environmental health or safety risks that 

the EPA has reason to believe may 

disproportionately affect children, per 

the definition of ‘‘covered regulatory 

action’’ in section 2–202 of the 

Executive Order. This action is not 

subject to Executive Order 13045 

because it merely proposes to 

disapprove a SIP submission as not 

meeting the CAA. 

H. Executive Order 13211, Actions That 

Significantly Affect Energy Supply, 

Distribution or Use 

This action is not subject to Executive 

Order 13211, because it is not a 

significant regulatory action under 

Executive Order 12866. 

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 

Executive Order 12898 (Federal 

Actions to Address Environmental 

Justice in Minority Populations and 

Low-Income Populations, 59 FR 7629, 

February 16, 1994) directs Federal 

agencies to identify and address 

‘‘disproportionately high and adverse 

human health or environmental effects’’ 

of their actions on minority populations 

and low-income populations to the 

greatest extent practicable and 

permitted by law. EPA defines 

environmental justice (EJ) as ‘‘the fair 

treatment and meaningful involvement 

of all people regardless of race, color, 

national origin, or income with respect 

to the development, implementation, 

and enforcement of environmental laws, 

regulations, and policies.’’ EPA further 

defines the term fair treatment to mean 

that ‘‘no group of people should bear a 

disproportionate burden of 

environmental harms and risks, 

including those resulting from the 

negative environmental consequences of 

industrial, governmental, and 

commercial operations or programs and 

policies.’’ 

Under the CAA, the Administrator is 

required to approve a SIP submission 

that complies with the provisions of the 

Act and applicable Federal regulations. 

42 U.S.C. 7410(k); 40 CFR 52.02(a). 

Thus, in reviewing SIP submissions, the 

EPA’s role is to review state choices, 

and approve those choices if they meet 

the minimum criteria of the Act. 

Accordingly, this proposed action 

disapproves state law as meeting 

Federal requirements and does not 

impose additional requirements beyond 

those imposed by state law. 

The air agency did not evaluate 

environmental justice considerations as 


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13032 Federal Register / Vol. 89, No. 35 / Wednesday, February 21, 2024 / Proposed Rules 

part of its SIP submittal; the CAA and 

applicable implementing regulations 

neither prohibit nor require such an 

evaluation. EPA did not perform an EJ 

analysis and did not consider EJ in this 

action. Due to the nature of the action 

being taken here, this action is expected 

to have a neutral to positive impact on 

the air quality of the affected area. 

Consideration of EJ is not required as 

part of this action, and there is no 

information in the record inconsistent 

with the stated goal of E.O. 12898 of 

achieving environmental justice for 

people of color, low-income 

populations, and Indigenous peoples. 

This action merely proposes to 

disapprove a SIP submission as not 

meeting the CAA. 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Incorporation by 

reference, Intergovernmental relations, 

Nitrogen dioxide, Ozone, Reporting and 

recordkeeping requirements, Volatile 

organic compounds. 

Adam Ortiz, 

Regional Administrator, Region III. 

[FR Doc. 2024–03528 Filed 2–20–24; 8:45 am] 

BILLING CODE 6560–50–P 


khammond on DSKJM1Z7X2PROD with PROPOSALS