
[Federal Register Volume 88, Number 155 (Monday, August 14, 2023)]
[Proposed Rules]
[Pages 54975-54982]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-16578]


=======================================================================
-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2023-0272; FRL-11237-01-R8]


Air Plan Approval and Disapproval; Colorado; Serious Attainment 
Plan Elements and Related Revisions for the 2008 8-Hour Ozone Standard 
for the Denver Metro/North Front Range Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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

SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve and disapprove portions of a state implementation plan (SIP) 
revision submitted by the State of Colorado to meet Clean Air Act (CAA) 
requirements for the 2008 8-hour ozone national ambient air quality 
standards (NAAQS) in the Denver Metro/North Front Range nonattainment 
area (DMNFR Area). Specifically, the EPA is proposing approval of the 
submitted enhanced monitoring SIP element as meeting applicable Serious 
area requirements for the 2008 8-hour ozone NAAQS, and is proposing 
disapproval of the contingency measure element and certain reasonably 
available control technology (RACT) SIP submittals. The EPA is taking 
this action pursuant to the CAA.

DATES: Written comments must be received on or before September 13, 
2023.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2023-0272, to the Federal Rulemaking Portal: https://www.regulations.gov. Follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or removed from 
www.regulations.gov. The 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. The 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, the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit https://www2.epa.gov/dockets/commenting-epa-dockets.
    Docket: All documents in the docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available electronically in 
www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Abby Fulton, Air and Radiation 
Division, EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver, 
Colorado, 80202-1129, telephone number: (303) 312-6563, email address: 
[email protected].

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,'' 
``us,'' or ``our'' is used, we mean the EPA.

I. What action is the EPA taking?

    As explained below, the EPA is proposing various actions on 
Colorado's proposed SIP revisions that were submitted respectively on 
March 22, 2021, and May 20, 2022. Specifically, we are proposing to 
approve the submitted enhanced monitoring SIP element as meeting 
applicable Serious area requirements for the 2008 8-hour ozone NAAQS. 
We are proposing disapproval of the contingency measures and the 
categorical RACT rules for refinery fueled process heaters as well as 
landfill or biogas fired reciprocating internal combustion engines 
(RICE) and the State's RACT determination for the Golden Aluminum 
facility.
    The basis for our proposed action is discussed in this proposed 
rulemaking.

II. Background

    On March 12, 2008, the EPA revised both the primary and secondary 
NAAQS for ozone to a level of 0.075 parts per million (ppm) (based on 
the annual fourth-highest daily maximum 8-hour average concentration, 
averaged over three years), to provide increased protection of public 
health and the environment.\1\ The 2008 ozone NAAQS retains the same 
general form and averaging time as the 0.08 ppm NAAQS set in 1997, but 
is set at a more protective level. Specifically, the 2008 8-hour ozone 
NAAQS is attained when the 3-year average of the annual fourth-highest 
daily maximum 8-hour average ambient air quality ozone concentrations 
is less than or equal to 0.075 ppm.\2\ Effective July 20, 2012, the EPA 
designated as nonattainment any area that was violating the 2008 8-hour 
ozone NAAQS based on the three most recent years (2008-2010) of air 
monitoring data.\3\ With that rulemaking, the DMNFR Area was designated 
nonattainment and classified as Marginal.\4\ Ozone nonattainment areas 
are classified based on the severity of their ozone levels, as 
determined using the area's design value. The design value is the 3-
year average of the annual fourth highest daily maximum 8-hour average 
ozone concentration at a monitoring site.\5\ Areas designated as 
nonattainment at the Marginal classification level were required to 
attain the 2008 8-hour ozone NAAQS no later than July 20, 2015, based 
on 2012-2014 monitoring data.\6\
---------------------------------------------------------------------------

    \1\ Final rule, National Ambient Air Quality Standards for 
Ozone, 73 FR 16436 (March 27, 2008). The EPA has since further 
strengthened the ozone NAAQS, but the 2008 8-hour standard remains 
in effect. See Final Rule, National Ambient Air Quality Standards 
for Ozone, 80 FR 65292 (Oct. 26, 2015).
    \2\ 40 CFR 50.15(b).
    \3\ Final rule, Air Quality Designations for the 2008 Ozone 
National Ambient Air Quality Standards, 77 FR 30088 (May 21, 2012).
    \4\ Id. at 30110. The nonattainment area includes Adams, 
Arapahoe, Boulder, Broomfield, Denver, Douglas and Jefferson 
Counties, and portions of Larimer and Weld Counties. See 40 CFR 
81.306.
    \5\ 40 CFR part 50, appendix I.
    \6\ 40 CFR 51.903.
---------------------------------------------------------------------------

    On May 4, 2016, the EPA published its determination that the DMNFR 
Area, among other areas, had failed to attain the 2008 8-hour ozone 
NAAQS by the attainment deadline, and that it was accordingly 
reclassified to Moderate ozone nonattainment status.\7\ Colorado 
submitted SIP revisions to the EPA on May 31, 2017 to meet the DMNFR 
Area's requirements under the Moderate classification.\8\ The EPA took 
final action on July 3, 2018, approving the majority of the May 31, 
2017 submittal, but deferring action on portions of the

[[Page 54976]]

submitted Regulation Number 7 (Reg. 7) RACT rules.\9\ On February 24, 
2021, the EPA took final action approving additional measures as 
addressing Colorado's RACT SIP obligations for Moderate ozone 
nonattainment areas.\10\ Areas that were designated as Moderate 
nonattainment were required to attain the 2008 8-hour ozone NAAQS no 
later than July 20, 2018, based on 2015-2017 monitoring data.\11\
---------------------------------------------------------------------------

    \7\ Final rule, Determinations of Attainment by the Attainment 
Date, Extensions of the Attainment Date, and Reclassification of 
Several Areas for the 2008 Ozone National Ambient Air Quality 
Standards, 81 FR 26697 (May 4, 2016).
    \8\ CAA section 182, 42 U.S.C. 7511a, outlines SIP requirements 
applicable to ozone nonattainment areas in each classification 
category. Areas reclassified as Moderate under the 2008 8-hour ozone 
NAAQS had a submittal deadline of January 1, 2017 for these SIP 
revisions (81 FR 26699).
    \9\ Final rule, Approval and Promulgation of State 
Implementation Plan Revisions; Colorado; Attainment demonstration 
for the 2008 8-Hour Ozone Standard for the Denver Metro/North Front 
Range Nonattainment Area, and Approval of Related Revisions (83 FR 
31068).
    \10\ Final rule, Approval and Promulgation of Implementation 
Plans; Colorado; Revisions to Regulation Number 7 and RACT 
Requirements for 2008 8-Hour Ozone Standard for the Denver Metro/
North Front Range Nonattainment Area, 86 FR 11125.
    \11\ See 40 CFR 51.903.
---------------------------------------------------------------------------

    On December 26, 2019, the EPA published its determination that the 
DMNFR Area, among other areas, had failed to attain the 2008 8-hour 
ozone NAAQS by the attainment deadline for Moderate areas, and that it 
was accordingly reclassified as Serious.\12\ Colorado submitted SIP 
revisions to the EPA on May 13, 2020, March 22, 2021, and May 20, 2022 
to meet the DMNFR Area's requirements under the Serious classification. 
The EPA took final action on the majority of these revisions on 
November 5, 2021,\13\ and May 9, 2023.\14\
---------------------------------------------------------------------------

    \12\ Final rule, Finding of Failure to Attain and 
Reclassification of Denver Area for the 2008 Ozone National Ambient 
Air Quality Standard, 84 FR 70897 (Dec. 26, 2019); see 40 CFR 
81.306.
    \13\ Final rule, Approval and Promulgation of Implementation 
Plans; Colorado; Revisions to Regulation Number 7; Aerospace, Oil 
and Gas, and Other RACT Requirements for the 2008 8-Hour Ozone 
Standard for the Denver Metro/North Front Range Nonattainment Area, 
86 FR 61071 (Nov. 5, 2021).
    \14\ Final rule, Air Plan Approval, Conditional Approval, 
Limited Approval and Limited Disapproval; Colorado; Serious 
Attainment Plan Elements and Related Revisions for the 2008 8-Hour 
Ozone Standard for the Denver Metro/North Front Range Nonattainment 
Area (88 FR 29827).
---------------------------------------------------------------------------

    The submittals that we are now proposing to act on include those 
revisions that we have not previously acted on that are addressing RACT 
for certain major sources of volatile organic compounds (VOC) or 
nitrogen oxides (NOX) as well as certain elements from the 
State's Serious ozone attainment plan.

III. Summary of the State's SIP Submittals

March 22, 2021 Submittal

    This submittal contains the State's Serious Ozone Attainment Plan 
(OAP) and revisions to Reg. 7 to include RACT requirements in 
Colorado's ozone SIP that apply a major source threshold of 50 tons per 
year (tpy) for sources of VOC and/or NOX.\15\ The Reg. 7 
revisions include expansion of categorical requirements to reduce VOC 
emissions related to wood surface coatings in part C, section I.O.; 
adding NOX emission limits for turbines, boilers, and 
landfill or biogas engines in part E, section II.; and adding 
categorical requirements to reduce VOC emissions related to foam 
manufacturing in part E, section V. The Reg. 7 revisions also include 
typographical, grammatical, and formatting corrections. We previously 
acted on all parts of this SIP submittal \16\ except for limited 
portions of Reg. 7 and parts of the OAP including the enhanced 
monitoring, contingency measures, attainment demonstration, and RACM 
elements. Here, we are proposing action on enhanced monitoring, 
contingency measures, the remaining outstanding Reg. 7 revisions,\17\ 
and RACT for landfill and biogas engines at Golden Aluminum. The EPA is 
not reopening previous actions where the Agency acted on other parts of 
this SIP submittal.
---------------------------------------------------------------------------

    \15\ See CAA sections 182(c) and 182(f).
    \16\ Final rule, Air Plan Approval, Conditional Approval, 
Limited Approval and Limited Disapproval; Colorado; Serious 
Attainment Plan Elements and Related Revisions for the 2008 8-Hour 
Ozone Standard for the Denver Metro/North Front Range Nonattainment 
Area, 88 FR 29827 (May 9, 2023).
    \17\ By letter dated July 5, 2023, the state withdrew its 
previous submission of an attainment demonstration and RACM for the 
Serious area SIP. Accordingly, the EPA does not have these items 
before it to act on, and we are therefore not proposing any action 
with respect to these two Serious area SIP elements.
---------------------------------------------------------------------------

May 20, 2022 Submittal

    This submittal contains amendments to Reg. 7 that establish 
categorical RACT requirements for major sources of NOX and 
certain control techniques guidelines (CTG)-covered sources in the 
DMNFR Area. Specifically, on July 16, 2021, Colorado's Air Quality 
Control Commission (AQCC) adopted RACT requirements in Part C, section 
I. for miscellaneous metal parts coatings and Part E, section II. RACT 
requirements for process heaters at major sources of NOX 
emissions, along with various typographical, grammatical, and 
formatting corrections.
    We previously acted on all parts of this SIP submittal \18\ except 
for revisions in Reg. 7, Part E, section II.A.4. concerning categorical 
RACT rules for refinery fuel gas process heaters, which we are now 
proposing to act on. The EPA is not reopening previous actions where 
the Agency acted on other parts of this SIP submittal.
---------------------------------------------------------------------------

    \18\ Id.
---------------------------------------------------------------------------

IV. Procedural Requirements

    The CAA requires that states meet certain procedural requirements 
before submitting SIP revisions to the EPA, including the requirement 
that states adopt SIP revisions after reasonable notice and public 
hearing.\19\ For the March 22, 2021 submittal, the AQCC provided notice 
in the Colorado Register (CR) on October 10, 2020,\20\ and held a 
public hearing on the revisions on December 16, 2020. The Commission 
adopted the revisions on December 18, 2020. The revisions became state-
effective on February 14, 2021.
---------------------------------------------------------------------------

    \19\ CAA section 110(a)(2), 42 U.S.C. 7410(a)(2).
    \20\ 43 CR 19.
---------------------------------------------------------------------------

    For the May 20, 2022 submittal, the AQCC provided notice in the 
Colorado Register on May 10, 2021,\21\ and held a public hearing on the 
revisions on July 16, 2021. The Commission adopted the revisions on 
July 16, 2021. The revisions became state-effective on September 14, 
2021.
---------------------------------------------------------------------------

    \21\ 44 CR 9.
---------------------------------------------------------------------------

V. The EPA's Evaluation of Colorado's Submittals

2008 Ozone Serious SIP Submittal

    CAA section 182 outlines SIP requirements applicable to ozone 
nonattainment areas in each classification category. A Serious area 
classification triggers requirements for state submittals described in 
CAA section 182(c) and further clarified in the EPA's regulations 
implementing the 2008 8-hour ozone NAAQS.\22\ Examples of these 
requirements include an attainment demonstration, reasonable further 
progress (RFP), an enhanced inspection and maintenance program, RACT, 
and RACM.
---------------------------------------------------------------------------

    \22\ See 40 CFR part 51, subpart AA.
---------------------------------------------------------------------------

    Colorado submitted SIP revisions to the EPA on March 22, 2021, to 
meet the requirements of a Serious area classification for the DMNFR 
Area.
    The following subsections A through C discuss in turn each part of 
this SIP submittal that we are proposing to act on.

A. Enhanced Monitoring

1. Background
    Section 182(c)(1) of the CAA requires that SIPs for all ozone 
nonattainment areas classified as Serious or higher ``contain measures 
to improve the ambient monitoring'' of ozone, NOX, and VOC. 
This subsection also requires the EPA to promulgate regulations for 
enhanced monitoring of these pollutants. As highlighted in the 2008 
Ozone SIP Requirements Rule (SRR), the EPA's monitoring regulations, 
including

[[Page 54977]]

the enhanced monitoring network for ozone referred to as the 
Photochemical Assessment Monitoring Stations (PAMS) network, are in 40 
CFR part 58.\23\
---------------------------------------------------------------------------

    \23\ The 2008 ozone SIP requirements rule addresses PAMS-related 
requirements. See 80 FR 12264 at 12291 (March 6, 2015).
---------------------------------------------------------------------------

    In 2006, the EPA significantly revised and reorganized 40 CFR part 
58.\24\ As revised, 40 CFR part 58 no longer requires that SIPs contain 
a demonstration of compliance with monitoring regulations. Instead, 
compliance with the EPA's monitoring regulations is established through 
the Agency's review of required annual monitoring network plans.\25\ 
The 2008 Ozone SRR made no changes to these requirements. The 2015 
ozone SRR noted that the PAMS provisions in 40 CFR part 58 had been 
revised, with the intent ``to provide a more spatially dispersed 
monitoring network, reduce potential redundancy and improve data value 
while providing monitoring agencies flexibility in collecting 
additional information needed to understand their specific ozone 
issues.'' \26\ These revisions did not alter the 40 CFR part 58 
approach under which compliance with monitoring regulations is 
established by EPA review of annual monitoring network plans.
---------------------------------------------------------------------------

    \24\ 71 FR 61236 (Oct. 17, 2006).
    \25\ 40 CFR 58.2(b) now provides that, ``The requirements 
pertaining to provisions for an air quality surveillance system in 
the SIP are contained in this part.''
    \26\ 83 FR 62998, 63008 (Dec. 06, 2018).
---------------------------------------------------------------------------

2. Evaluation
    Colorado's March 21, 2021 SIP submittal contained a section 
addressing the enhanced monitoring requirement of CAA 182(c)(1) by 
reference to existing provisions that the EPA previously approved into 
the SIP.\27\ On September 23, 1993, the EPA approved revisions to 
Colorado's SIP for air quality monitoring, consistent with the 
requirements of 40 CFR part 58, as part 58 was written at that 
time.\28\ The revisions addressed air quality surveillance network 
design, network description, station designations, air quality 
monitoring criteria, data reporting, annual review of the State's 
monitoring network, prevention of significant deterioration monitoring, 
and public notification. The monitoring provisions are located in 
Colorado's Air Quality Monitoring SIP \29\ and provide for the 
continued implementation, maintenance, and enforcement of the State air 
pollution control program for meeting the NAAQS. Additionally, the OAP 
SIP chapter 2 provides an overview of PAMS requirements and describes 
how the State is complying with the requirements. This includes the 
development and implementation of an Enhanced Monitoring Plan (EMP) 
detailing enhanced ozone and ozone precursor monitoring activities to 
be performed. The EMP was sent to the EPA on October 2, 2019, after a 
30-day comment period,\30\ and is included as a Technical Support 
Document attached to the Serious OAP. The OAP also explains that the 
State operates an air quality monitoring network of State/Local Air 
Monitoring Systems (SLAMS) monitors in accordance with EPA 
regulations.\31\ Furthermore, the EPA approved Colorado's most recent 
annual monitoring network plan, which includes a description of the 
State's PAMS, on August 3, 2022.\32\
---------------------------------------------------------------------------

    \27\ See p. 2-1 of the OAP.
    \28\ 58 FR 49434.
    \29\ Contained within the docket for this action.
    \30\ See ``State of Colorado Enhanced Monitoring Plan for 
Ozone'', CDPHE, Air Pollution Control Division (Oct. 1, 2019), 
contained within the March 22, 2021 submittal, available in the 
docket. https://www.colorado.gov/airquality/tech_doc_repository.aspx#network_plan.
    \31\ P. 2-8 of the OAP.
    \32\ Letter from Monica Morales, EPA, to Michael Ogletree, 
CDPHE, available in the docket for this action.
---------------------------------------------------------------------------

    Colorado collected 2006-2019 ozone monitoring data in accordance 
with monitoring requirements in 40 CFR part 58 as well as with the 
EPA's ``Quality Assurance Handbook for Air Pollution Measurement 
Systems, Vol. II--Ambient Air Quality Monitoring Program''; \33\ the 
APCD Quality Management Plan; \34\ the APCD Quality Assurance Project 
Plan; \35\ and Colorado's monitoring network plan.\36\
---------------------------------------------------------------------------

    \33\ QA Handbook for Air Pollution Measurement Systems: ``Volume 
II: Ambient Air Quality Monitoring Program'' (EPA-454/B-13-003, May 
2013) (available in the docket). The current version of the Handbook 
is available at https://www3.epa.gov/ttn/amtic/files/ambient/pm25/qa/FinalHandbookDocument1_17.pdf (EPA-454/B-17-001, Jan. 2017).
    \34\ Colorado Department of Public Health and Environment, 
Quality Management Plan (Feb 2018), available at https://www.colorado.gov/airquality/tech_doc_repository.aspx?action=open&file=APCD_QMP_03102016.pdf.
    \35\ Colorado Department of Public Health and Environment, 
Quality Assurance Project Plan (July 2015), available at https://www.colorado.gov/airquality/tech_doc_repository.aspx?action=open&file=QAPP_2018.pdf.
    \36\ Annual Network Plans available at https://www.colorado.gov/airquality/tech_doc_repository.aspx.
---------------------------------------------------------------------------

    The monitoring section of Colorado's OAP includes:
     A description of the State's EMP and PAMS monitoring plan;
     A reference to Colorado's monitoring SIP;
     Information on the location of ozone monitors in Colorado, 
from southern Metropolitan Denver to northern Fort Collins (including 
Rocky Mountain National Park);
     A list of fourth-maximum monitored 8-hour ozone values 
from 2006 through 2019, including levels recorded above the 75 parts 
per billion (ppb) 2008 ozone NAAQS; \37\
---------------------------------------------------------------------------

    \37\ OAP Table 10, p. 2-3.
---------------------------------------------------------------------------

     A description of the State's ambient air quality data 
assurance program; and
     Relevant 8-hour-average ozone monitoring data and recovery 
rates from 2006 through 2019.
    Based on our review and approval of the State's monitoring SIPs and 
the 2022 annual monitoring network plan, we propose to find that 
Colorado has satisfied the enhanced monitoring requirements under CAA 
section 182(c)(1) for the DMNFR Area with respect to the 2008 ozone 
NAAQS.

B. Contingency Measures

1. Background
    Under the CAA, states with ozone nonattainment areas classified 
under subpart 2 as Moderate or higher must adopt and submit 
nonattainment plans that include contingency measures consistent with 
section 172(c)(9). Similarly, states with ozone nonattainment areas 
classified as Serious or higher must include contingency measures 
consistent with section 182(c)(9). Contingency measures are additional 
controls or measures to be implemented in the event the area fails to 
meet RFP or fails to attain the NAAQS by the applicable attainment 
date. The SIP submittal should identify such controls or measures, 
specify a schedule for implementation, and indicate that the measures 
will be implemented without significant further action by the state or 
the EPA.\38\
---------------------------------------------------------------------------

    \38\ See 70 FR 71612 (November 29, 2005); see also 80 FR 12264, 
12285 (March 6, 2015).
---------------------------------------------------------------------------

    In the September 12, 2016 decision by the U.S. Court of Appeals for 
the Ninth Circuit in Bahr v. EPA, the court concluded that contingency 
measures must be measures that only take effect when an area fails to 
meet RFP or attain by the applicable attainment date, not before.\39\ 
After the Bahr decision, the EPA recognized that within the geographic 
jurisdiction of the Ninth Circuit (which does not include Colorado), 
the language of CAA sections 172(c)(9) and 182(c)(9) require 
contingency measures to be both prospective (i.e., that they be 
undertaken in the future) and conditional (i.e., that implementation is 
conditional upon the area's failure to

[[Page 54978]]

meet RFP or to attain by the applicable attainment date).\40\
---------------------------------------------------------------------------

    \39\ 836 F.3d 1218, 1235-1237.
    \40\ The Bahr v. EPA decision involved a challenge to an EPA 
approval of contingency measures under the general nonattainment 
area plan provisions for contingency measures in CAA section 
172(c)(9), but, given the similarity between the statutory language 
in section 172(c)(9) and the additional ozone-specific contingency 
measure provision in section 182(c)(9), the EPA found that the 
decision affected how it should interpret both sections of the Act 
in the Ninth Circuit.
---------------------------------------------------------------------------

    On January 29, 2021, the U.S. Court of Appeals for the District of 
Columbia Circuit in Sierra Club v. EPA issued a decision in response to 
challenges to the EPA's rule implementing the 2015 ozone NAAQS.\41\ In 
Sierra Club v. EPA, the D.C. Circuit endorsed the holding of Bahr and 
vacated the EPA's interpretation of the CAA that had allowed states to 
rely on already-implemented control measures to meet the statutory 
requirements of section 172(c)(9) or 182(c)(9) for contingency measures 
in nonattainment plans for the ozone NAAQS.\42\ The effect of this 
decision is that the CAA interpretation that contingency measures must 
be prospective and conditional applies across the U.S.\43\
---------------------------------------------------------------------------

    \41\ 985 F.3d 1055, 1067-68; 83 FR 62998 (Dec. 6, 2018).
    \42\ See 985 F.3d at 1067-68; 83 FR at 63026-27.
    \43\ In Sierra Club, the D.C. Circuit held that ``Contingency 
measures that are to take effect upon failure to satisfy standards 
are likewise not measures that have been implemented before such 
failure occurs.'' 985 F.3d at 1067-68 (internal quotations omitted).
---------------------------------------------------------------------------

    At the time Colorado was developing its Serious OAP, the EPA's 
long-standing interpretation of section 172(c)(9) was that states could 
rely on surplus emission reductions from already-implemented measures 
(i.e., implemented as of the time that the EPA acts on the SIP 
submittal) to meet the contingency measures requirements. Thus, states 
could rely on surplus emissions reductions from already-implemented 
Federal measures (e.g., Federal mobile source measures based on the 
incremental turnover of the motor vehicle fleet each year) or surplus 
emission reductions from already-implemented state or local measures in 
the SIP.
    The EPA has previously approved nonattainment area plan submittals 
under the now invalidated interpretation that already-implemented 
measures were permissible as contingency measures. That is, we have 
approved contingency measures that consisted of one or more Federal or 
state control measures already in place that provided reductions in 
excess of the reductions needed to meet other requirements or relied 
upon in the modeled attainment demonstration.\44\ However, after the 
D.C. Circuit's January 2021 Sierra Club decision, the EPA can no longer 
interpret the CAA to allow approval of already-implemented measures as 
meeting the requirements of CAA sections 172(c)(9) or 182(c)(9) for any 
nonattainment plan submittal (even if, as is the case here, the 
development of the submittal was nearing conclusion when the decision 
was issued). Contingency measures must be prospective and conditional--
they must be measures that would take effect when the area fails to 
meet RFP or attain by the applicable attainment date, not before.
---------------------------------------------------------------------------

    \44\ See, e.g., 62 FR 15844 (April 3, 1997) (direct final rule 
approving an Indiana ozone SIP revision); 62 FR 66279 (December 18, 
1997) (final rule approving an Illinois ozone SIP revision); 66 FR 
30811 (June 8, 2001) (direct final rule approving a Rhode Island 
ozone SIP revision); 66 FR 586 (Jan. 3, 2001) (final rule approving 
District of Columbia, Maryland, and Virginia ozone SIP revisions); 
and 66 FR 634 (Jan. 3, 2001) (final rule approving a Connecticut 
ozone SIP revision).
---------------------------------------------------------------------------

2. Evaluation
    For the DMNFR Area 2008 ozone NAAQS Serious nonattainment area, the 
contingency measures the State submitted as part of the March 22, 2021 
SIP submittal consist of surplus emissions reductions from already-
implemented control measures. The State relied on the surplus emissions 
reductions from such already-implemented measures to demonstrate 
compliance with the contingency measure requirements of the CAA.\45\ 
The State determined the emissions reductions from these measures to be 
surplus, in that the State did not rely upon them in the OAP for 
demonstrating RFP or attainment, and in that no additional actions are 
required to garner these additional emission reductions after the 
attainment year regardless of whether the area attained. The March 22, 
2021 SIP submittal explained that these surplus emission reductions 
would occur after the July 20, 2021 Serious attainment date, and thus 
the State identified them as contingency measures for the DMNFR Area. 
These measures consist of projected emission reductions from Federal 
vehicle and engine emissions certification programs and from fuel 
control programs for both on-road and non-road vehicles which were 
already adopted by the EPA, the implementation of which does not depend 
on whether a nonattainment area attains or meets its RFP 
requirements.\46\ The State concluded that the projected combined VOC 
and NOX emissions reductions of over three percent for the 
DMNFR Area to be achieved in 2022 (from the 2011 baseline) satisfies 
the CAA requirements for contingency measures.
---------------------------------------------------------------------------

    \45\ See Chapter 10 of the OAP.
    \46\ See chapter 4 of the OAP for a description of mobile source 
emission reduction measures.
---------------------------------------------------------------------------

    In evaluating the DMNFR Area contingency measures in the March 22, 
2021 SIP submittal, we must consider whether they are both prospective 
and conditional, consistent with the D.C. Circuit's decision in Sierra 
Club. Because these contingency measures consist entirely of emission 
reductions from measures that will occur regardless of whether the 
nonattainment area fails to meet RFP or to attain by the applicable 
attainment date, they do not satisfy the requirements of CAA sections 
172(c)(9) and 182(c)(9) that contingency measures be both prospective 
and conditional. Thus, we must propose to disapprove the contingency 
measures element of the March 22, 2021 SIP submittal.
    This proposed action concerning contingency measures will have no 
impact on the EPA's prior determinations with respect to RFP or other 
attainment plan requirements for the area and this NAAQS.

C. Reasonably Available Control Technology (RACT)

1. Background
    Section 172(c)(1) of the CAA requires that SIPs for nonattainment 
areas ``provide for the implementation of all reasonably available 
control measures as expeditiously as practicable (including such 
reductions in emissions from existing sources in the area as may be 
obtained through the adoption, at a minimum, of reasonably available 
control technology [RACT]).'' CAA section 182(b)(2) specifies that RACT 
is required for certain types of sources and pollutants within ozone 
nonattainment areas classified Moderate and higher. The EPA has defined 
RACT as ``[t]he lowest emissions limitation that a particular source is 
capable of meeting by the application of control technology that is 
reasonably available considering technological and economic 
feasibility.'' \47\ States must submit a SIP revision requiring the 
implementation of RACT for each source in the area covered by a CTG, 
and for any major source of VOC or NOX in the area.\48\
---------------------------------------------------------------------------

    \47\ General Preamble for Proposed Rulemaking on Approval of 
Plan Revisions for Nonattainment Areas--Supplement (on Control 
Techniques Guidelines), 44 FR 53761 (Sep. 17, 1979).
    \48\ See CAA section 182(b)(2), 42 U.S.C. 7511a(b)(2)); see also 
Note, RACT Qs & As--Reasonably Available Control Technology (RACT): 
Questions and Answers, William Harnett, Director, Air Quality Policy 
Division, EPA (May 2006), available at https://www.regulations.gov/document/EPA-R08-OAR-2020-0114-0008.

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

[[Page 54979]]

    For a Moderate, Serious, or Severe area, a major stationary source 
is one that emits, or has the potential to emit, 100, 50, or 25 tpy or 
more, respectively, of VOCs or NOX.\49\ Accordingly, for the 
DMNFR Serious nonattainment area, a major stationary source is one that 
emits, or has the potential to emit, 50 tpy or more of VOCs or 
NOX.\50\
---------------------------------------------------------------------------

    \49\ See CAA sections 182(b), 182(c), 182(d), 182(f)(1), and 
302(j).
    \50\ On October 7, 2022 the EPA finalized an action that 
reclassified the DMNFR Area to Severe nonattainment status for the 
2008 ozone NAAQS. See Final rule, Determinations of Attainment by 
the Attainment Date, Extensions of the Attainment Date, and 
Reclassification of Areas Classified as Serious for the 2008 Ozone 
National Ambient Air Quality Standards, 87 FR 60926. Accordingly, 
the State of Colorado is required to submit a demonstration that the 
area will attain the Severe standard, and other elements of a Severe 
SIP.
---------------------------------------------------------------------------

    On reclassification as Serious nonattainment, the DMNFR Area was 
required to implement RACT as expeditiously as practicable, but no 
later than August 3, 2020, for RACT needed for demonstrating attainment 
and July 20, 2021, for RACT not needed for demonstrating 
attainment.\51\ The Division conducted a series of analyses and 
rulemakings to address 2008 ozone Moderate and Serious RACT 
requirements.
---------------------------------------------------------------------------

    \51\ Final rule, Finding of Failure to Attain and 
Reclassification of Denver Area for the 2008 Ozone National Ambient 
Air Quality Standard, 84 FR 70897, 70900 (Dec. 26, 2019); see also 
Final rule, Determination of Attainment Date, Extensions of the 
Attainment Date, and Reclassification of Several Areas Classified as 
Moderate for the 2008 Ozone National Ambient Air Quality Standards, 
84 FR 44238 (Aug. 23, 2019).
---------------------------------------------------------------------------

    The EPA approved the majority of the State's CTG RACT analysis on 
July 3, 2018.\52\ On February 24, 2021, the EPA approved categorical 
RACT requirements for combustion equipment at major sources, RACT 
requirements for major sources of VOC and NOX, and 
additional CTG VOC source RACT rules.\53\ On November 5, 2021, the EPA 
approved additional RACT requirements for major sources of VOC and 
NOX in the DMNFR Area under the Serious classification, 
including expanded categorical combustion equipment and new categorical 
general solvent use requirements.\54\ Finally, the EPA took action on 
several other RACT categories as part of its May 9, 2023 
rulemaking.\55\
---------------------------------------------------------------------------

    \52\ See 83 FR 31068. A negative declaration as to RACT for 
sources covered by the aerospace CTG was approved on November 5, 
2021 (86 FR 61071). Colorado's RACT demonstrations for sources 
covered by the industrial cleaning solvents, metal furniture 
coatings (2007), and wood furniture CTGs were approved on February 
24, 2021 (86 FR 11127); and the State's RACT demonstration for 
sources covered by the oil and gas CTG was conditionally approved on 
May 13, 2022 (87 FR 29228).
    \53\ 86 FR 11127.
    \54\ Final rule, Approval and Promulgation of Implementation 
Plans; Colorado; Revisions to Regulation Number 7; Aerospace, Oil 
and Gas, and Other RACT Requirements for the 2008 8-Hour Ozone 
Standard for the Denver Metro/North Front Range Nonattainment Area 
86 FR 61071 (Nov. 5, 2021).
    \55\ 88 FR 29827.
---------------------------------------------------------------------------

    The RACT submittals that we are now proposing to act on include 
those that we have not previously acted on that address RACT for 
several non-CTG VOC and NOX sources and categories.
2. Evaluation
    In preparing its RACT determinations, Colorado reviewed source 
permits, consulted with Division permitting and enforcement staff 
involved with each source, and consulted with the sources 
themselves.\56\ Colorado also considered control strategies identified 
in the CTGs, Alternative Control Techniques (ACTs), RACT/Best Available 
Control Technology/Lowest Achievable Emission Rate Clearinghouse 
(RBLC), EPA's Menu of Control Measures,\57\ New Source Performance 
Standards (NSPS), National Emission Standards for Hazardous Air 
Pollutants (NESHAP), and Colorado's regulations. For major sources, 
Colorado identified a list of major VOC and NOX sources in 
the DMNFR Area subject to RACT requirements under Moderate and Serious 
classifications.\58\
---------------------------------------------------------------------------

    \56\ See Colorado's Technical Support Document for Reasonably 
Available Control Technology for Major Sources, December 14, 2020. 
Available within the docket.
    \57\ See https://www.epa.gov/air-quality-implementation-plans/menu-control-measures-naaqs-implementation.
    \58\ See chapter 6.3 of the OAP.
---------------------------------------------------------------------------

a. Landfill and Biogas Fired RICE
    Colorado's March 22, 2021 submittal contains categorical RACT rules 
for landfill gas or biogas fired reciprocating internal combustion 
engines (RICE) in Reg. 7, Part E, section II.A.4.f. Colorado evaluated 
technical information submitted by operators of five landfill or 
biogas-fired spark ignition engines and determined that additional add 
on emission controls are not RACT. Colorado then established a limit of 
2.0 grams NOX per brake horsepower hour (g/bhp-hr) based on 
a 30-day rolling average for landfill or biogas-fired engines with a 
design power output greater than or equal to 500 hp and less than 1,350 
hp.
    The EPA's evaluation of the RACT analyses submitted to the AQCC by 
the two facilities that still have engines subject to section 
II.A.4.f., appears to show that they are meeting a limit below 1.5 g 
NOX/hp-hr.\59\ It is therefore unclear how a 2.0 g 
NOX/bhp-hr limit could be representative of RACT. Colorado 
has not provided sufficient information within the SIP submittal and 
associated documents for the EPA to determine that the proposed limit 
of 2.0 g NOX/bhp-hr constitutes RACT. Additionally, there 
are no emission monitoring requirements to determine NOX 
emission rates for landfill or biogas fired engines in section 
II.A.4.f. Without such requirements, the EPA cannot determine 
compliance with the applicable numerical emissions limitation. This is 
a problem for purposes of meeting the RACT requirement. We conclude 
that this was likely inadvertently excluded from the regulation, 
because the statement of basis provides that ``owners or operators of 
these engines will continue to comply with the combustion process 
adjustment, periodic performance testing, and recordkeeping 
requirements.'' \60\ Finally, the recordkeeping provisions in Reg. 7, 
Part E, section II.A.7., require owners and operators to maintain 
records for a period of five years and to make those records available 
to the Division upon request. In a recent final action by the EPA, we 
explained that records must be periodically submitted to the State and 
made publicly available for citizens' ability to participate in the 
enforcement of the SIP as allowed by CAA section 304.\61\
---------------------------------------------------------------------------

    \59\ See Leprino Foods and Waste Management RACT Analyses, 
available within the docket. We note that at the time of rule 
development, there were biogas engines located at Boulder Wastewater 
Treatment Plant with higher limits, but these engines are no longer 
in use. The engines were removed from the facility and appropriate 
cancellations were submitted.
    \60\ See ``Reg Lang & SBSP Adopted_R7'' within the March 22, 
2021 submittal.
    \61\ 88 FR 29827 (May 9, 2023).
---------------------------------------------------------------------------

    For these reasons, we propose to disapprove the categorical RACT 
rules for landfill and biogas fired RICE.
b. Golden Aluminum
    Colorado's March 22, 2021 submittal identifies Golden Aluminum, an 
individual aluminum sheet manufacturing facility, as a major VOC and 
NOX source. Equipment and operations at the facility include 
rigid can stock shredders, a delacquering kiln, three furnaces, 
degassing boxes, hot mill press and coiling, annealing furnaces, cold 
mill and spray, recoiling, coil coating line, packaging and an 
emergency generator. To address these emitting points the State 
reviewed the EPA's RBLC for metal coil surface coating and 
miscellaneous boilers, furnaces, and heaters. The RBLC, which

[[Page 54980]]

is an EPA database of air permit determinations that can help identify 
appropriate emissions control technologies, did not list any control 
measures for metal coil surface coating. For miscellaneous boilers, 
furnaces, and heaters, the RBLC listed low-NOX combustion 
technology, natural gas as fuel, selective catalytic reduction, 
efficient boiler design, low-NOX burners, and good 
combustion practices as potential control measures. For annealing 
furnaces, the RBLC listed low-NOX burners, combustion of 
clean fuel, and good combustion practices as potential control 
measures. The Division also conducted an analysis for operating the 
three furnaces at the facility in a natural gas/oxygen/air mixture 
mode. Colorado determined that compliance with the EPA CTG for coil 
coating operations,\62\ on which Reg. 7, Part C, section I.D. is based, 
and with combustion process adjustments in Reg. 7, Part E, section II., 
constitutes RACT for the Golden Aluminum facility.
---------------------------------------------------------------------------

    \62\ Control of Volatile Organic Emissions from Existing 
Stationary Sources, Volume II: Surface Coating of Cans, Coils, 
Paper, Fabrics, Automobiles, and Light-Duty Trucks, EPA.-450/2-77-
008 (May 1977). ``Coil Coating CTG''.
---------------------------------------------------------------------------

    There is one cold rolling mill at the facility with a permit limit 
of 67.38 tpy of VOC, which is above the applicable 50 tpy major source 
threshold for RACT. Emissions from this unit are controlled with an air 
purifier centrifugal separator. Beyond referencing the coil coatings 
requirements in Reg. 7 that are based on the EPA's Coil Coating CTG, 
and which apply to the coil coating operation at the facility, VOC 
emitting points such as the cold rolling mill were not further analyzed 
for RACT. This cold rolling mill is not covered by the Coil Coating 
CTG, and therefore that CTG is not relevant for purposes of determining 
RACT for the cold rolling mill. The level of analysis provided in the 
submittal is not sufficient for purposes of demonstrating that the cold 
rolling mill is subject to RACT-level controls. The Reg. 7 coil coating 
requirements apply to the coating applicators, ovens, and quench areas 
of coil coating operations occurring after the cold rolling process, 
and are therefore not relevant to the control of VOC emissions 
associated with lubricant oil use during operation of the cold rolling 
mill. The Reg. 7, Part C, section I.D. coil coating requirements that 
are referenced in the State's RACT analysis, and which are based on the 
applicable CTG, apply only to the coil coating operation, which is a 
different process than the cold rolling mill, which functions to shape 
the metal to a specified thickness.\63\ Therefore, the State's SIP 
submittal does not contain any RACT analysis that is specific to the 
VOC emissions from the cold rolling mill itself. The cold rolling mill 
has not been sufficiently analyzed with respect to RACT.
---------------------------------------------------------------------------

    \63\ See Technical Support Document for Reasonably Available 
Control Technology for Major Sources, Dec. 2020. Contained within 
the State's March 22, 2021 SIP submittal. Available within the 
docket.
---------------------------------------------------------------------------

    In its 2008 ozone SIP requirements rule, the EPA described how 
states should meet RACT requirements. States are to consider existing 
CTGs and (ACTs) ``as well as all relevant information (including recent 
technical information and information received during the public 
comment period) that is available at the time that they are developing 
their RACT SIPs for the 2008 ozone NAAQS.'' \64\ In June 1992, the EPA 
released a technical guidance project report titled ``Control of VOC 
Emissions from Nonferrous Metal Rolling Processes,'' \65\ which 
presents information on nonferrous metal rolling processes, VOC 
emissions generated during these operations, emission control 
techniques and their effectiveness, and costs associated with process 
changes and emission control options. This report includes information 
regarding the control of VOC emissions from cold rolling process 
equipment like the cold rolling mill at Golden Aluminum. The report was 
available at the time the Division was developing their RACT SIP for 
the 2008 ozone NAAQS under the Serious classification. Also, other 
states have evaluated RACT for cold rolling mills independently from 
CTG-covered emission points.\66\ The aforementioned technical report, 
relevant regulations in other states, the RBLC Clearinghouse, the EPA's 
Menu of Control Measures, NSPS, and NESHAP are all resources that may 
be considered in evaluating RACT for cold rolling process equipment.
---------------------------------------------------------------------------

    \64\ Final rule, ``Implementation of the 2008 National Ambient 
Air Quality Standards for Ozone: State Implementation Plan 
Requirements,'' 80 FR 12264, 12279 (March 6, 2015).
    \65\ EPA-453/R-92-001.
    \66\ For example, see the Missouri non-CTG RACT rule for control 
of VOC emissions from aluminum foil rolling at 76 FR 66013 (October 
25, 2011). Available at https://www.regulations.gov/document/EPA-R07-OAR-2011-0859-0001.
---------------------------------------------------------------------------

    Because we conclude that RACT was not fully evaluated for the cold 
mill located at Golden Aluminum, we are proposing to disapprove the 
State's determination that RACT has been met for this facility. To 
address this disapproval, if it is finalized, we recommend that the 
Division evaluate the current emissions from the cold rolling mill and 
the effectiveness of the control device, conduct an analysis of whether 
further VOC reduction is technically and economically feasible for the 
cold rolling mill through the application of RACT, and determine if 
appropriate emission limits (including work practices) and associated 
monitoring and recordkeeping should be adopted as a SIP revision for 
purposes of meeting RACT.
c. Refinery Fueled Process Heaters
    Colorado's May 20, 2022 submittal contains categorical RACT rules 
for refinery fueled process heaters in Reg. 7, Part E, section II.A. 
The rules establish an emission limit of 0.1 pounds of NOX 
per million British thermal units (lb NOX/MMBtu) for 
refinery gas-fired process heaters with a heat input rate greater than 
or equal to 5 MMBtu/hr. Reg. 7, Part E, section II.A. also establishes 
performance testing requirements, and associated recordkeeping, for 
refinery gas-fired process heaters greater than or equal to 100 MMBtu/
hr. We proposed approval of the revisions on November 9, 2022.\67\ 
During the comment period, we received adverse comments regarding the 
categorical RACT limit for refinery-fueled process heaters. We did not 
act on this category in our May 9, 2023 final rule.
---------------------------------------------------------------------------

    \67\ 87 FR 67617.
---------------------------------------------------------------------------

    After further evaluation of the State's submitted RACT rules and 
technical information, we are proposing to find that the proposed 
emission limit in Reg. 7 is not enforceable for all refinery fueled 
process heaters, either because performance testing is not required or 
feasible, or because the unit does not have a continuous emission 
monitoring system (CEMS). Colorado's Technical Support Document for 
Reasonably Available Control Technology for Major Sources \68\ explains 
that there are significant challenges for performance testing including 
``lack of test ports, lack of platforms and safe access, and a 
refractory lining in some stacks.'' \69\ Nonetheless, CAA 110(a)(2)(A) 
requires the SIP to include ``enforceable emission limitations.'' The 
lack of testing or CEMS for some sources means that neither the State 
nor the EPA have a method to determine whether those sources are 
meeting the numerical emission limit of 0.1 lb NOX/MMBtu. 
There is no way to determine whether these sources are complying with 
the limit or whether the limit represents

[[Page 54981]]

RACT for the specific units. Therefore, the categorical RACT limit is 
not enforceable for all refinery fueled process heaters controlled in 
Reg. 7.
---------------------------------------------------------------------------

    \68\ July 12, 2021, contained within the May 16, 2022 submittal.
    \69\ Id. at p. 11.
---------------------------------------------------------------------------

    Furthermore, the State's record that accompanies the SIP submittal 
does not adequately demonstrate how the state determined that the limit 
of 0.1 lb NOX/MMBtu constitutes RACT for these sources. As 
explained above, the majority of refinery fueled process heaters have 
not had testing to establish an emission baseline. As such, the 
submittal is unclear on the amount of emissions coming from these 
sources. The State's RACT analysis does not assess emission reductions 
that could be achievable through the application of lower emitting 
technology, nor does is discuss costs of such technology, presumably in 
part due to the lack of baseline emissions information. The EPA cannot 
fully determine that the State's limit constitutes RACT without 
additional information regarding baseline emissions as well as 
potential control options and associated costs. Lastly, there are some 
units covered by the regulation that have low NOX burners 
and ultra low NOX burners, which have been shown through 
initial performance testing or the operation of CEMS to meet emission 
rates below the proposed categorical limit of 0.1 lb NOX/
MMBtu.\70\ This demonstrates to the EPA that the categorical limit may 
not be appropriate for these units. The State does not explain why its 
proposed limit represents RACT when information included in the record 
indicates these sources are capable of achieving a lower limit. The 
State has not provided sufficient information in its SIP submittal and 
associated documents to allow the EPA to conclude that the categorical 
RACT limit for refinery fueled process heaters is representative of 
RACT. For these reasons, we propose to disapprove the categorical RACT 
rules for refinery fueled process heaters.
---------------------------------------------------------------------------

    \70\ See columns N and V of the Suncor Heaters spreadsheet, 
available within the docket.
---------------------------------------------------------------------------

VI. Proposed Action

    We propose to approve the enhanced monitoring element of the OAP 
submittal from the State of Colorado for the DMNFR Area submitted on 
March 22, 2021, as explained in section V.A. of this document. In light 
of the D.C. Circuit's decision in Sierra Club v. EPA, we propose to 
disapprove the contingency measure element of the March 22, 2021 OAP 
for the Serious nonattainment area under the 2008 8-hour ozone NAAQS. 
Additionally, we propose to disapprove certain RACT SIP revisions, as 
explained in section V.C. of this document. The EPA proposes 
disapproval of the contingency measures with respect to the 
requirements of CAA 172(c)(9) and 182(c)(9). The EPA proposes 
disapproval of RACT requirements with respect to the requirements of 
CAA sections 172(c)(1), 182(b)(2), and 182(c).
    Under section 179(a) of the CAA, final disapproval of a submittal 
that addresses a requirement of part D, title I of the CAA starts 
sanctions clocks. The March 22, 2021 and May 20, 2021 SIP revision 
submittals, including the contingency measures and RACT elements for 
the DMNFR 2008 ozone NAAQS nonattainment area, do address requirements 
of part D, and thus if the EPA finalizes this proposed disapproval, the 
sanctions clocks for these elements would start on the effective date 
of the final action.\71\
---------------------------------------------------------------------------

    \71\ Under 40 CFR 52.31, the offset sanction in CAA section 
179(b)(2) would be imposed 18 months after the effective date of 
that final disapproval action, and, unless an exemption applies, the 
highway funding sanction in CAA section 179(b)(1) would be imposed 
six months after the offset sanction. Sanctions would not be imposed 
if the EPA determined, via a final approval, that a subsequent SIP 
submittal corrected the identified deficiencies before the 
applicable deadlines.
---------------------------------------------------------------------------

    Additionally, section 110(c)(1) of the CAA requires the 
Administrator to promulgate a Federal implementation plan (FIP) at any 
time within two years after the Administrator finds that a state has 
failed to make a required SIP submittal, finds a SIP submittal to be 
incomplete, or disapproves a SIP submittal, unless the state corrects 
the deficiency, and the Administrator approves the SIP revision, before 
the Administrator promulgates a FIP. Therefore, if the EPA finalizes 
this proposed disapproval, the EPA will be obligated under CAA section 
110(c)(1) to promulgate a FIP within two years after the effective date 
of the disapproval, unless the State submits and the EPA approves SIP 
revisions to correct the identified deficiencies in the rules before 
the EPA promulgates the FIP.
    The EPA is soliciting public comments on the proposed actions 
discussed in this document. We will accept comments from the public on 
this proposal for the next 30 days and will consider comments before 
taking final action.

VII. Environmental Justice Considerations

    The EPA reviewed demographic data, which provides an assessment of 
individual demographic groups of populations living within the DMNFR 
Area. The EPA then compared the data to the national averages for each 
of the demographic groups. The results of this analysis are being 
provided for informational and transparency purposes. The results of 
the demographic analysis indicate that for populations within the DMNFR 
Area, there are census block groups in which the percentage of people 
of color (persons who reported their race as a category other than 
White alone and/or Hispanic or Latino) is greater than the national 
average of 39% with some census block groups ranking above the 80th 
percentile.\72\ There are also census block groups within the DMNFR 
Area where the percentage of low income population is above the 
national average of 33% with some census block groups ranking above the 
80th percentile.\73\
---------------------------------------------------------------------------

    \72\ See ``EJSCREEN Maps'' pdf, available within the docket.
    \73\ Id.
---------------------------------------------------------------------------

    This proposed action identifies deficiencies in the contingency 
measure element of the March 22, 2021 SIP submittal for the DMNFR Area 
under the 2008 8-hour ozone NAAQS. The EPA's disapproval of these 
contingency measures, if finalized, would require that Colorado submit 
plans for the DMNFR Area containing prospective and conditional 
contingency measures consistent with the D.C. Circuit decision, which 
would help to improve air quality in the entire affected nonattainment 
area through ongoing reductions of ozone precursor emissions should 
those measures be triggered. Additionally, this action identifies 
deficiencies in the State's March 22, 2021 and May 20, 2022 RACT 
submittals. The EPA has defined RACT as the lowest emission limitation 
that a particular source is capable of meeting by the application of 
control technology that is reasonably available considering 
technological and economic feasibility. The CAA requires this action, 
and the EPA recognizes the adverse impacts of ozone. Information on 
ozone and its relationship to negative health impacts can be found in 
the National Ambient Air Quality Standards for Ozone.\74\ We expect 
that this action and resulting emissions reductions will generally be 
neutral or contribute to reduced environmental and health impacts on 
all populations in the DMNFR Area, including people of color and low-
income populations. At a minimum, this action would not worsen any 
existing air quality and is expected to ensure the area is meeting 
requirements to attain and/or maintain air quality standards. Further, 
there is no information in the record indicating that

[[Page 54982]]

this action is expected to have disproportionately high or adverse 
human health or environmental effects on a particular group of people.
---------------------------------------------------------------------------

    \74\ Final rule, 73 FR 16436 (March 12, 2008).
---------------------------------------------------------------------------

VIII. Statutory and Executive Order Reviews

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

    This proposed action is not a significant regulatory action and was 
therefore not submitted to the Office of Management and Budget (OMB) 
for review.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the PRA, because this proposed SIP disapproval, if finalized, will not 
in and of itself create any new information collection burdens, but 
will simply disapprove certain State requirements for inclusion in the 
SIP.

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 will not impose any requirements on small entities. This 
proposed SIP disapproval, if finalized, will not in and of itself 
create any new requirements but will simply disapprove certain State 
requirements for inclusion in the SIP.

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. This action proposes to disapprove certain pre-
existing requirements under State or local law, and imposes no new 
requirements. Accordingly, no additional costs to State, local, or 
tribal governments, or to the private sector, result from this action.

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, because the SIP revision that the EPA is 
proposing to disapprove would not apply on any Indian reservation land 
or in any other area where the EPA or an Indian tribe has demonstrated 
that a tribe has jurisdiction and will not impose substantial direct 
costs on tribal governments or preempt tribal law. 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 this proposed SIP disapproval, if 
finalized, will not in and of itself create any new regulations, but 
will simply disapprove certain State requirements for inclusion in the 
SIP.

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 (NTTAA)

    Section 12(d) of the NTTAA directs the EPA to use voluntary 
consensus standards in its regulatory activities unless to do so would 
be inconsistent with applicable law or otherwise impractical. The EPA 
believes that this action is not subject to the requirements of section 
12(d) of the NTTAA because application of those requirements would be 
inconsistent with the CAA.

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. 
The EPA defines environmental justice (EJ) as the ``fair treatment and 
meaningful involvement of all people regardless of race, color, 
national origin, or income with respect to the development, 
implementation, and enforcement of environmental laws, regulations, and 
policies.'' EPA further defines the term fair treatment to mean that 
``no group of people should bear a disproportionate burden of 
environmental harms and risks, including those resulting from the 
negative environmental consequences of industrial, governmental, and 
commercial operations or programs and policies.''
    The State did not evaluate EJ considerations as part of its SIP 
submittal; the CAA and applicable implementing regulations neither 
prohibit nor require such an evaluation. The EPA performed an EJ 
analysis, as is described above in the section titled ``Environmental 
Justice Considerations.'' The analysis was done for the purpose of 
providing additional context and information about this rulemaking to 
the public, not as a basis of the action. Due to the nature of the 
action being taken here, this action is expected to have a positive 
impact on the air quality of the affected area. In addition, there is 
no information in the record upon which this decision is based 
inconsistent with the stated goal of E.O. 12898 of achieving 
environmental justice for people of color, low-income populations, and 
Indigenous peoples.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
Greenhouse gases, Incorporation by reference, Intergovernmental 
relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting 
and recordkeeping requirements, Sulfur oxides, Volatile organic 
compounds.

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

    Dated: July 31, 2023.
KC Becker,
Regional Administrator, Region 8.
[FR Doc. 2023-16578 Filed 8-11-23; 8:45 am]
BILLING CODE 6560-50-P


