Document ID: EPA-R08-OAR-2022-0632-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: Colorado; Serious Attainment Plan Elements and Related Revisions for the 2008 8-Hour Ozone Standard for the Denver Metro/North Front Range Nonattainment Area
Posted Date: 2022-11-09T05:00Z

[Federal Register Volume 87, Number 216 (Wednesday, November 9, 2022)]
[Proposed Rules]
[Pages 67617-67634]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-24075]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2022-0632; FRL-10362-01-R8]

Air Plan Approval; 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.

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SUMMARY: On March 22, 2021, the State of Colorado submitted State 
Implementation Plan (SIP) revisions related to attainment of the 2008 
8-hour ozone National Ambient Air Quality Standards (NAAQS) for the 
Denver Metro/North Front Range (DMNFR) Serious nonattainment area by 
the applicable attainment date of July 20, 2021. The Environmental 
Protection Agency (EPA) proposes to approve the majority of the 
submittal, including base and future year emission inventories, a 
reasonable further progress (RFP) demonstration, a reasonably available 
control measures (RACM) analysis, a motor vehicle inspection and 
maintenance (I/M) program, a nonattainment new source review (NNSR) 
program, 2020 motor vehicle emissions budgets (MVEBs) and 
transportation controls, a clean fuel fleet program, and revisions to 
Colorado Air Quality Control Commission (Commission or AQCC) 
regulations for the control of ozone via ozone precursors and control 
of hydrocarbons via oil and gas emissions. The EPA is also proposing to 
approve portions of the reasonably available control technology (RACT) 
analyses and revisions from submissions made on May 13, 2020; May 18, 
2021; and May 20, 2022. Finally, the EPA proposes to approve revisions 
from submissions made on May 14, 2018, May 13, 2020, and May 20, 2022 
that were conditionally approved on May 13, 2022. This action is being 
taken in accordance with the Clean Air Act (CAA).

DATES: Written comments must be received on or before December 9, 2022.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2022-0632, 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 http://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. To reduce the risk of COVID-19 transmission, for 
this action we do not plan to offer hard copy review of the docket. 
Please email or call the person listed in the FOR FURTHER INFORMATION 
CONTACT section if you need to make alternative arrangements for access 
to the docket.

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.
    The information presented in this document is organized as follows:

I. What action is EPA taking?
II. Background
III. Summary of the State's SIP Submittals
IV. Procedural Requirements
V. The EPA's Evaluation of Colorado's Submissions
    A. Emissions Inventories
    B. Reasonable Further Progress Demonstration
    C. Reasonably Available Control Technology (RACT) Analysis
    D. Reasonably Available Control Measures (RACM) Analysis
    E. Motor Vehicle Inspection and Maintenance Program (I/M) 
Program
    F. Nonattainment New Source Review (NNSR)
    G. Motor Vehicle Emissions Budget (MVEB)/Transportation 
Conformity
    H. Clean Fuel Fleet Program
    I. SIP Control Measures
VI. Proposed Action
VII. Consideration of Section 110(l) of the CAA
VIII. Environmental Justice Considerations
IX. Incorporation by Reference
X. Statutory and Executive Order Reviews

I. What action is EPA taking?

    As explained below, the EPA is proposing various actions on 
Colorado's proposed SIP revisions that were submitted on May 13, 2020, 
March 22, 2021, May 18, 2021, and May 20, 2022. Specifically, we are 
proposing to approve portions of Colorado's Serious attainment plan for 
the 2008 8-hour ozone NAAQS. In addition, we propose to approve the 
MVEBs and revisions to Regulation Number 7 (Reg. 7) contained in the 
State's submittal. We also propose to approve all other aspects of the 
submittal, except for the RACT submission for certain sources and 
enhanced monitoring, which we will be acting on at a later date, and 
for the attainment demonstration and contingency measures. We are also 
proposing to approve revisions to Colorado Regulation Number 21 (Reg. 
21) from the State's May 13, 2020 submittal, and to Reg. 7 from the 
State's May 18, 2021 submittal. Finally, we are proposing to approve 
the Reg. 7 revisions from the State's May 14, 2018, May 13, 2020, and 
May 20, 2022

[[Page 67618]]

submittals that were conditionally approved on May 13, 2022.\1\
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    \1\ Final rule, Air Plan Conditional Approval; Colorado; 
Revisions to Regulation Number 7 and Oil and Natural Gas RACT 
Requirements for 2008 8-Hour Ozone Standard for the Denver Metro/
North Front Range Nonattainment Area, 87 FR 29228.
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    The basis for our proposed action is discussed in this proposed 
rulemaking. Technical information that we rely upon in this proposal is 
in the docket, which is available at http://www.regulations.gov, Docket 
No. EPA-R08-OAR-2022-0632.

II. Background

2008 8-Hour Ozone NAAQS Nonattainment

    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 3 years), to provide increased protection of public 
health and the environment.\2\ 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.\3\ 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.\4\ With that rulemaking, the Denver-Boulder-Greeley-
Ft. Collins-Loveland, Colorado area (Denver or DMNFR Area) area was 
designated nonattainment and classified as Marginal.\5\ 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.\6\ 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.\7\
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    \2\ 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).
    \3\ 40 CFR 50.15(b).
    \4\ Final rule, Air Quality Designations for the 2008 Ozone 
National Ambient Air Quality Standards, 77 FR 30088 (May 21, 2012).
    \5\ 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.
    \6\ 40 CFR part 50, appendix I.
    \7\ See 40 CFR 51.903.
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    On May 4, 2016, the EPA published its determination that the Denver 
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.\8\ Colorado 
submitted SIP revisions to the EPA on May 31, 2017 to meet the Denver 
Area's requirements under the Moderate classification.\9\ 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 submitted Reg. 
7 RACT rules.\10\ On February 24, 2021, the EPA took final action 
approving additional measures as addressing Colorado's RACT SIP 
obligations for Moderate ozone nonattainment areas.\11\ 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.\12\ On December 26, 2019, the EPA published its 
determination that the Denver 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 Serious ozone nonattainment 
status.\13\
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    \8\ 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).
    \9\ CAA section 182, 42 U.S.C. 7511a, outlines SIP requirements 
applicable to ozone nonattainment areas in each classification 
category. Areas classified Moderate under the 2008 8-hour ozone 
NAAQS had a submission deadline of January 1, 2017 for these SIP 
revisions (81 FR 26699).
    \10\ 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).
    \11\ 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.
    \12\ See 40 CFR 51.903.
    \13\ 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.
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III. Summary of the State's SIP Submittals

    We are proposing to take action on Colorado SIP submittals made on 
five different dates:

May 14, 2018 Submittal

    This submittal contains amendments to Reg. 7, sections XII 
(Volatile Organic Compound Emissions from Oil and Gas Operations) and 
XVIII (Natural Gas-Actuated Pneumatic Controllers Associated with Oil 
and Gas Operations) to meet RACT for oil and gas sources covered by the 
EPA's 2016 Oil and Gas Control Techniques Guidelines (CTG).\14\ We 
previously acted on all parts of this SIP submittal \15\ except for 
revisions to Reg. 7, section XII.J.1., concerning centrifugal 
compressors, as to which we proposed conditional approval. We are now 
proposing approval of those revisions.
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    \14\ Control Techniques Guidelines for the Oil and Natural Gas 
Industry, EPA-453/B-16-001 (Oct. 2016).
    \15\ 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).
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May 13, 2020 Submittals

    On this date the State submitted two SIP revisions. One of the 
submittals includes a full reorganization of Reg. 7 into parts A-E, 
amends oil and gas storage tank requirements, updates RACT requirements 
for major sources of volatile organic compounds (VOC) and nitrogen 
oxides (NOX) in the DMNFR Area, updates requirements for 
gasoline transport truck testing and vapor control systems, and 
contains typographical, grammatical, and formatting corrections 
throughout. We previously acted on all parts of this SIP submittal \16\ 
except for revisions to Reg. 7, sections I.D., I.E, and I.F. concerning 
storage tanks, and section I.J.1. concerning centrifugal compressors, 
as to which we proposed conditional approval. We are now proposing 
approval of those revisions.
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    \16\ 86 FR 61071 (Nov. 5, 2021).
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    The second submittal contains new Reg. 21 to limit the VOC content 
in consumer products and in architectural and industrial maintenance 
(AIM) coatings manufactured, distributed, or sold in the DMNFR Area. 
Specifically, the Commission adopted VOC standards in the Ozone 
Transport Commission (OTC) AIM coatings model rule phase 2 (2014) and 
VOC standards in the OTC consumer products model rule phase 4 (2013). 
Reg. 21 includes definitions, exemptions, labeling, and recordkeeping 
provisions based on the OTC model rules.

March 22, 2021 Submittal

    This submittal contains the State's Serious ozone attainment plan 
and revisions to Reg. 7 to include RACT requirements in Colorado's 
ozone SIP for 50 tons per year (tpy) major sources of VOC and/or 
NOX. The Reg. 7 revisions include expansion of

[[Page 67619]]

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. 
Typographical, grammatical, and formatting corrections were also made.

May 18, 2021 Submittal

    The state regulations included with this submittal contain mostly 
state-only revisions that have not been submitted for inclusion in the 
SIP. Portions of these regulations submitted as SIP revisions include 
typographical, grammatical, and formatting corrections to the outline 
of Reg. 7 and part E (combustion equipment at major source RACT).

May 20, 2022 Submittals

    On this date the State submitted three SIP revisions. One of the 
submittals contains amendments that were mostly state-only and not 
submitted as SIP revisions. The SIP revisions adopted by the AQCC on 
Feb. 19, 2021 include updates to definitions in Reg. 7, part D, section 
III (natural gas-actuated pneumatic controllers associated with oil and 
gas operations).
    Another submittal contains amendments to Reg. 7 that establish 
categorical RACT requirements for major sources of NOX and 
certain CTG sources in the DMNFR Area. Specifically, on July 16, 2021 
the 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. Typographical, grammatical, and formatting corrections were 
also made.
    The third submittal contains revisions concerning RACT requirements 
for oil and gas sources. Specifically, on Dec. 17, 2021 the AQCC 
adopted revisions to Reg. 7, part D, section I for performance or 
manufacturer testing for combustion equipment used to control emissions 
from storage vessels and wet seal centrifugal compressors as to which 
we proposed conditional approval. We are now proposing approval of 
those revisions.

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.\17\ For the May 14, 2018 submittal, the AQCC provided notice 
in the Colorado Register on August 10, 2017 \18\ and held public 
hearings on the revisions on October 19 and 20, 2017. The Commission 
adopted the revisions on November 17, 2017. The revisions became state-
effective on December 30, 2017.
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    \17\ CAA section 110(a)(2), 42 U.S.C. 7410(a)(2).
    \18\ 40 CR 15 available at https://www.sos.state.co.us/CCR/RegisterHome.do.
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    For the May 13, 2020 (part D, oil and gas) submittal, the AQCC 
provided notice in the Colorado Register on October 10, 2019 \19\ and 
held public hearings on the revisions on December 17-19, 2019. The 
Commission adopted the revisions on December 19, 2019. The revisions 
became state-effective on February 14, 2020.
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    \19\ 42 CR 19.
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    For the May 13, 2020 (Reg. 21) submittal, the AQCC provided notice 
in the Colorado Register on May 10, 2019 \20\ and held a public hearing 
on the revisions on July 18, 2019. The Commission adopted the revisions 
on November 17, 2016. The revisions became state-effective on September 
14, 2019.
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    \20\ 42 CR 9.
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    For the March 22, 2021 submittal, the AQCC provided notice in the 
Colorado Register on October 10, 2020 \21\ 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.
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    \21\ 43 CR 19.
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    For the May 18, 2021 submittal, the AQCC provided notice in the 
Colorado Register on July 10, 2020 \22\ and held a public hearing on 
the revisions on September 17, 2020. The Commission adopted the 
revisions on September 23, 2020. The revisions became state-effective 
on November 14, 2020.
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    \22\ 43 CR 13.
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    For the May 20, 2022 submittal (part D, Definitions) the AQCC 
provided notice in the Colorado Register on January 10, 2021 \23\ and 
held a public hearing on the revisions on February 18, 2021. The 
Commission adopted the revisions on February 18, 2021. The revisions 
became state-effective on April 14, 2021.
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    \23\ 44 CR 1.
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    For the May 20, 2022 submittal (Misc. Metals and Process Heater) 
the AQCC provided notice in the Colorado Register on May 10, 2021 \24\ 
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.
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    \24\ 44 CR 9.
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    For the May 20, 2022 submittal (part D, Oil and Gas) the AQCC 
provided notice in the Colorado Register on October 10, 2021 \25\ and 
held a public hearing on the revisions on December 14, 2021. The 
Commission adopted the revisions on December 17, 2021. The revisions 
became state-effective on January 30, 2022.
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    \25\ 44 CR 19.
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    Accordingly, we propose to find that Colorado met the CAA's 
procedural requirements for reasonable notice and public hearing.

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

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 submissions described in 
the EPA's regulations implementing the 2008 8-hour ozone NAAQS.\26\ 
Examples of these requirements include submission of a modeling and 
attainment demonstration, RFP, an enhanced inspection and maintenance 
program, RACT, and RACM. Serious nonattainment areas had a submission 
deadline of August 3, 2020 for these SIP revisions.\27\
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    \26\ See 40 CFR part 51, subpart AA.
    \27\ See 84 FR 70897 (Dec. 26, 2019).
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    Colorado submitted SIP revisions to the EPA on March 22, 2021, to 
meet the requirements of a Serious area classification for the DMNFR 
Area. Colorado's proposed SIP revisions consist of the parts listed 
below.
     8-Hour Ozone Attainment Plan (OAP), which includes 
monitoring information, emission inventories, an RFP demonstration, an 
attainment demonstration using photochemical grid modeling, a RACT 
analysis, a RACM analysis, a motor vehicle emissions I/M program, NNSR 
program certification, contingency measures, MVEBs for transportation 
conformity, and a clean fuel fleet program.
     Revisions to Reg. 7.

A. Emissions Inventories

1. Background
    CAA section 172(c)(3), requires that each SIP include a 
``comprehensive, accurate, current inventory of actual emissions from 
all sources of the relevant pollutant or pollutants in [the] area.'' 
The accounting required by this section provides a ``base year'' 
inventory that serves as the starting point for

[[Page 67620]]

attainment demonstration air quality modeling, for assessing RFP, and 
for determining the need for additional SIP control measures. An 
attainment year inventory is a projection of future emissions and is 
necessary to show the effectiveness of SIP control measures. Both the 
base year and attainment year inventories are necessary for 
photochemical modeling to demonstrate attainment. As previously noted, 
we are not acting on the attainment modeling demonstration in this 
action, but are evaluating Colorado's emission inventories for purposes 
of meeting RFP requirements.
    Colorado's DMNFR Serious area attainment plan includes a 2011 base 
year inventory, a 2017 milestone year inventory, and a 2020 attainment 
year inventory. The inventories catalog NOX and VOC 
emissions, because these pollutants are precursors to ozone formation, 
across all source categories during a typical summer day, when ozone 
formation is pronounced. The State developed an updated 2017 
``milestone year'' emissions inventory for the Serious nonattainment 
area. When initially developed for the Moderate area SIP, the 2017 
inventory was calculated based on projected values. The 2017 inventory 
approved as part of the Moderate area SIP has been updated for the 
purposes of the Serious area SIP using data collected in 2017 \28\ and 
methodologies as presented in chapter 3 of the OAP.
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    \28\ Pursuant to 40 CFR 51.1110(b), the values in the submitted 
2011 base year EI are actual ozone season day emissions.
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2. Evaluation
    The 2011 base year inventory was included as part of the Moderate 
area SIP submittal and approved as part of our July 3, 2018 action.\29\ 
As part of the Moderate area SIP, a projected 2017 attainment year 
emissions inventory was developed and approved by the EPA on July 3, 
2018.\30\ Due to the reclassification of the DMNFR to Serious 
nonattainment for the 2008 ozone NAAQS, CDPHE prepared an updated 2017 
emissions inventory based on currently available data in accordance 
with the EPA's revised guidance on emissions inventory 
developments.\31\ The updated 2017 emissions inventory was resubmitted 
to meet the State's Serious area SIP requirements.\32\
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    \29\ 83 FR 31068 (July 3, 2018).
    \30\ Id.
    \31\ See ``Emission Inventory Guidance for Implementation of 
Ozone and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze Regulations,'' EPA-454/B-17-002. Revised 
May 2017.
    \32\ CAA section 182(c)(2)(B).
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    The 2017 milestone year emissions inventories are in tons per 
summer day and represent the most current available data, as of the 
time of submission, for emissions estimates for an average episode day 
during the peak summer ozone season of June through September. This 
includes actual data for the oil and gas sector and stationary sources 
in addition to newer data from updated regional transportation demand 
models used by the two Metropolitan Planning Organizations in the DMNFR 
Area.
    The 2020 inventory is in tons per summer day and represents 
emissions estimates for an average episode day during the peak summer 
ozone season (June through September). The 2020 inventory for VOC and 
NOX accounts for emissions growth associated with changes in 
population, fuel use, and economic activity as well as emissions 
reductions associated with controls that were in place as SIP control 
measures by the beginning of the 2020 summer ozone season. The EPA has 
provided guidance on developing emission projections to be used with 
models and other analyses for demonstrating attainment of air quality 
goals for ozone.\33\
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    \33\ Emissions Inventory Guidance for Implementation of Ozone 
and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze Regulations (May 2017) (``Emissions 
Inventory Guidance''), available at https://www.epa.gov/sites/default/files/2017/07/documents/ei_guidance_may_2017_final_rev.pdf.
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    The 2017 milestone year and 2020 attainment emission inventories 
were developed using EPA-approved emissions models, methodology, and 
guidelines for stationary, mobile, and area emission sources.
    The 2017 emissions inventories for power plants (also referred to 
as electric generating units) and other point sources were developed 
using Colorado Air Pollutant Emission Notice (APEN) reported data for 
each year, as specified in Tables 16 and 17 of the OAP. Area sources 
include many categories of emissions, such as coatings, household and 
personal care products, pesticides, and sealants. The 2017 area source 
emissions inventory is included in Table 18 of the OAP. The inventory 
was based on the EPA's 2014 National Emissions Inventory (NEI) and was 
derived from the 2014 NEI based on county population projections from 
the Colorado State Demography Office. The EPA finds that these sources 
(including those in the oil and gas sector) were adequately accounted 
for in the emissions inventory. The methodology used to calculate 
emissions for each respective category was consistent with 
recommendations and explanations in relevant EPA guidance,\34\ employed 
applicable approved emission factors and NEI data, and was sufficiently 
documented in the SIP and in the State's technical support documents 
(TSD).\35\
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    \34\ Emissions Inventory Guidance; MOVES2014, MOVES2014a, and 
MOVES2014b Technical Guidance: Using MOVES to Prepare Emission 
Inventories for State Implementation Plans and Transportation 
Conformity, EPA-420-B-18-039 (Aug. 2018) (``MOVES Guidance''), 
available at https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100V7EY.pdf.
    \35\ See Colorado Serious SIP submittal, TSD for Mobile and Area 
Sources Emissions Inventory Development. Available within the docket 
for this action.
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    Projected future emissions in 2020 were based on anticipated 
growth, technological advancements, and expected emissions controls 
that were to be implemented by the 2020 ozone season. The 2020 oil and 
gas emission inventory was based on 2017 actual site-specific emissions 
and 2018 APEN reported data, including technology and production and 
projected 2020 emissions and production. The 2020 emissions inventory 
for EGUs was developed based on Colorado APEN reported data for 2018 
and is specified in Table 28 of the OAP. The future year inventory for 
other point sources beyond EGUs is based on 2018 APEN data. The 2020 
area source inventory is provided in Table 30 of the OAP and was grown 
from the EPA's 2014 NEI based on county population projections from the 
State Demography Office. Reductions from implementation of Colorado 
AQCC Reg. 21 were then applied.\36\ On-road and non-road mobile source 
emissions for the 2020 inventory were calculated using the EPA's 
MOVES2014b \37\ model combined with local activity inputs including 
vehicle miles traveled (VMT) and average speed data, as well as local 
fleet, age distribution, meteorology, and fuels information. Table 34 
of the OAP includes biogenic emissions as part of the overall 2020 
future year emissions inventory.
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    \36\ See section I. SIP Control Measures of this document for a 
discussion of Reg. 21 controls.
    \37\ EPA's Motor Vehicle Emission Simulator (MOVES) is a state-
of-the-science emission modeling system that estimates emissions for 
mobile sources at the national, county, and project level for 
criteria air pollutants, greenhouse gases, and air toxics. See 
https://www.epa.gov/moves.
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    Table 1 shows the emissions by source category from the 2011 base 
year, 2017 milestone year, and 2020 attainment year emission 
inventories.

[[Page 67621]]

                                                            Table 1--Emissions Inventory Data
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                                                                       2011                            2017                            2020
                       Description                       -----------------------------------------------------------------------------------------------
                                                                VOC             NOX             VOC             NOX             VOC             NOX
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Area (non-oil and gas) Total............................            60.6  ..............            65.3  ..............            54.6  ..............
                                                         -----------------------------------------------------------------------------------------------
    Non-Road Total......................................            58.2            75.9              44  ..............            44.3            39.1
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                                                                   Oil and Gas Sources
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Area....................................................            48.9            22.2            43.6            38.1            54.5            34.4
Condensate/Oil Tanks....................................             216             1.1           107.7             1.4            50.2             0.6
Point...................................................            14.8            18.1              12            11.5            14.3            13.1
                                                         -----------------------------------------------------------------------------------------------
    Oil and Gas Total...................................           279.7            41.4           163.3            51.0           119.0            48.2
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                                                                         On-Road
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Light-Duty Vehicles.....................................            90.0           102.5            55.6            53.5            47.6            41.4
                                                         -----------------------------------------------------------------------------------------------
Medium/Heavy-Duty Vehicles..............................             3.7            39.6             2.0            14.9             1.8            13.3
                                                         -----------------------------------------------------------------------------------------------
    On-Road Total.......................................            93.7           142.1            57.6            68.4            49.4            54.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Point Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           EGU                                       0.7            39.7             0.3             9.4             0.4             4.6
Non-EGU.................................................            25.9            21.0            22.6            15.8            24.6            17.1
                                                         -----------------------------------------------------------------------------------------------
    Point Total.........................................            26.6            60.7  ..............  ..............              25            21.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
        Total Anthropogenic Emissions...................           518.8             320           353.1           187.1           292.3           163.7
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Details of Colorado's emissions inventory development are in 
Colorado's supporting TSD.\38\ The inventories in the SIP are based on 
the most current and accurate information available to the State and 
the Regional Air Quality Council (RAQC) at the time the SIP was being 
developed. Additionally, the inventories comprehensively address source 
categories in the DMNFR nonattainment area, and were developed 
consistent with the relevant EPA inventory guidance. For these reasons, 
we propose to approve the 2017 milestone inventory and the 2020 
inventory, which will be used to meet RFP requirements.\39\ The 
following section discusses RFP further.
---------------------------------------------------------------------------

    \38\ See Colorado Serious SIP submittal, TSD for Mobile and Area 
Sources Emissions Inventory Development. Available within the docket 
for this action.
    \39\ The EPA approved Colorado's 2011 base year inventory in our 
July 3, 2018 action (83 FR 31068).
---------------------------------------------------------------------------

B. Reasonable Further Progress Demonstration

1. Background
    CAA section 182(b)(1) and the EPA's 2008 Ozone Implementation Rule 
\40\ require each 8-hour ozone nonattainment area designated Moderate 
and above to submit an RFP demonstration for review and approval into 
its SIP that describes how the area will achieve actual VOC and 
NOX emissions reductions from a baseline emissions 
inventory. CAA section 182(b)(1), which is part of the ozone-specific 
nonattainment plan requirements of subpart 2 of the CAA, requires RFP 
to demonstrate a 15% reduction in VOC emissions. To satisfy the section 
182(b)(1) RFP requirement, on May 31, 2017 Colorado submitted an RFP 
demonstration showing VOC emission reductions greater than 15% over the 
six years after the 2011 base year inventory (i.e., 2012-2017). The EPA 
approved this 15% RFP SIP on July 3, 2018.\41\
---------------------------------------------------------------------------

    \40\ 80 FR 12264, 12266 (March 6, 2015).
    \41\ 83 FR 31068. The state's 15% RFP demonstration was also 
sufficient to satisfy the more general CAA subpart 1 requirements of 
CAA section 172(c)(2), which permits a combination of VOC and 
NOX emission reductions to show RFP.
---------------------------------------------------------------------------

    As noted above, the CAA section 182(b)(1) requirement for a 15% RFP 
demonstration applies to ozone nonattainment areas classified Moderate 
and above. In addition, Serious ozone nonattainment areas are subject 
to the CAA section 182(c)(2)(B) requirement to submit SIP revisions 
showing a 9% reduction of VOC \42\ emissions over each consecutive 
three-year period beginning six years after redesignation until the 
attainment date. For the DMNFR Area, the redesignation date was July 
20, 2012. Accordingly, the DMNFR Area was required to submit SIP 
revisions showing that 9% reductions in ozone precursor emissions would 
be achieved between January 1, 2018 and December 31, 2020.
2. Evaluation
    We reviewed the State's 9% RFP submittal for consistency with the 
requirements of the CAA and EPA regulations and guidance. To 
demonstrate compliance with RFP requirements, the State compared its 
2017 milestone VOC inventory against its projected 2020 VOC emissions 
inventory and demonstrated that the projected 2020 emissions of VOC 
were at least 9% below the 2011 base year inventory. Colorado projected 
an 11.7% reduction in VOC emissions from 2017-2020.\43\ As discussed in 
section V.A. of this document, the EPA reviewed the procedures Colorado 
used to develop its projected inventories and the State's submittal for 
consistency with the requirements of the CAA and the EPA's regulations 
and guidance and found them to be reasonable. We therefore

[[Page 67622]]

propose approval of Colorado's Serious-area RFP demonstration.
---------------------------------------------------------------------------

    \43\ See OAP, Table 35 on page 4-21. This projection has proven 
to be correct. See the ``Denver Metro Area/North Front Range 
Nonattainment Area Milestone Compliance Demonstration,'' March 31, 
2021 and the EPA's 2020 milestone compliance demonstration adequacy 
letter, July 6, 2021. Available in the docket for this action.
---------------------------------------------------------------------------

C. Reasonably Available Control Technology (RACT) Analysis

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).'' The EPA has defined ``reasonably available 
control technology'' (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.'' \44\ The EPA provides guidance concerning what 
types of controls may constitute RACT for a given source category by 
issuing Control Techniques Guidelines (CTG) and Alternative Control 
Techniques (ACT) documents.\45\ States must submit a SIP revision 
requiring the implementation of RACT for each source category in the 
area for which the EPA has issued a CTG, and for any major source in 
the area not covered by a CTG.\46\
---------------------------------------------------------------------------

    \44\ General Preamble for Proposed Rulemaking on Approval of 
Plan Revisions for Nonattainment Areas--Supplement (on Control 
Techniques Guidelines), 44 FR 53761 (Sep. 17, 1979).
    \45\ See https://www.epa.gov/ground-level-ozone-pollution/control-techniques-guidelines-and-alternative-control-techniques for 
a list of EPA-issued CTGs and ACTs.
    \46\ 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.
---------------------------------------------------------------------------

    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.\47\ 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. RACT can be adopted in the form of emission limitations 
or ``work practice standards or other operation and maintenance 
requirements,'' as appropriate.\48\
---------------------------------------------------------------------------

    \47\ See CAA sections 182(b), 182(c), 182(d), 182(f)(1), and 
302(j).
    \48\ See Memorandum, ``Approval Options for Generic RACT Rules 
Submitted to Meet the non-CTG VOC RACT Requirement and Certain 
NOX RACT Requirements,'' Sally Shaver, Director, Air 
Quality Strategies & Standards Division, EPA (Nov. 7, 1996), 
available at https://www.epa.gov/sites/production/files/2016-08/documents/shavermemogenericract_7nov1996.pdf.
---------------------------------------------------------------------------

    On reclassification to Serious status, 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.\49\ The 
Division conducted a series of analyses and rulemakings to address 2008 
ozone Moderate and Serious RACT requirements.
---------------------------------------------------------------------------

    \49\ 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 Seceral Areas Classified as 
Moderate for the 2008 Ozone National Ambient Air Quality Standards, 
84 FR 44238 (Aug. 23, 2019).
---------------------------------------------------------------------------

    As part of its May 31, 2017 Moderate ozone attainment plan, the 
Division conducted RACT analyses to demonstrate that the RACT 
requirements for CTG and major sources in the DMNFR Area had been 
fulfilled. The Division conducted these RACT analyses for VOC and 
NOX by listing state regulations implementing or exceeding 
RACT requirements for each CTG or non-CTG category at issue, and by 
detailing the basis for concluding that these regulations fulfilled 
RACT, through comparison with established RACT requirements described 
in the CTG and ACT guidance documents and rules developed by other 
state and local agencies. The EPA approved the majority of the State's 
CTG RACT analysis on July 3, 2018.\50\
---------------------------------------------------------------------------

    \50\ 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).
---------------------------------------------------------------------------

    In July 2018, the Commission adopted categorical RACT requirements 
for combustion equipment at major sources under the Moderate 
classification that the Commission had determined in 2016 were not 
addressed by SIP RACT requirements. In November 2019, the Commission 
adopted SIP requirements to include provisions that implement RACT for 
major sources of VOC and NOX under the Serious 
classification and for additional CTG VOC source categories in the 
Area. Specifically, the Commission adopted categorical RACT 
requirements for combustion equipment at major sources, major source 
breweries, and wood furniture manufacturing, and addressed the EPA's 
concerns with industrial cleaning solvent and metal furniture surface 
coating requirements. The EPA approved these revisions on February 24, 
2021.\51\
---------------------------------------------------------------------------

    \51\ 86 FR 11127.
---------------------------------------------------------------------------

    In December 2019, the Commission adopted 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. The EPA approved the majority of these revisions on 
November 5, 2021.\52\ The State re-reviewed its point source inventory 
as part of the March 22, 2021 Serious OAP submittal to verify that non-
CTG major sources (50 tpy) of VOC or NOX emissions in the 
DMNFR Area are subject to requirements that meet or exceed RACT.\53\
---------------------------------------------------------------------------

    \52\ 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).
    \53\ See appendix 6-E of the OAP.
---------------------------------------------------------------------------

    The RACT submissions that we are now proposing to approve include 
those that we have not previously acted on that are addressing RACT for 
several non-CTG VOC and NOX sources and categories. We are 
also proposing to convert to a full approval our previous conditional 
approval of submissions made on May 14, 2018, May 13, 2020, and May 20, 
2022, concerning RACT related to the Oil and Gas CTG.
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.\54\ Colorado also considered control strategies identified 
in the CTGs, ACTs, RBLC, EPA's Menu of Control Measures, New Source 
Performance Standards (NSPS), emission guidelines, National Emission 
Standards for Hazardous Air Pollutants (NESHAP), and in Colorado's 
regulations and determined that Colorado's major sources are currently 
subject to federally enforceable emission limits or requirements 
similar to measures described in these documents and regulations.\55\ 
In 2019, Colorado incorporated by reference some NSPS and NESHAP 
requirements into its SIP and expanded the applicability of some

[[Page 67623]]

existing RACT requirements. A summary of our proposed action with 
respect to each of these RACT categories follows.
---------------------------------------------------------------------------

    \54\ See Colorado's Technical Support Document for Reasonably 
Available Control Technology for Major Sources, December 14, 2020. 
Available within the docket.
    \55\ See id.

                 Table 2--Categories, Proposed Action, and Corresponding Sections of Submittals
----------------------------------------------------------------------------------------------------------------
               Category                    Proposed action               Location of RACT demonstration
----------------------------------------------------------------------------------------------------------------
Oil and gas..........................  Approval (converting     Technical Support Document for Reasonably
                                        previous conditional     Available Control Technology for the Oil and
                                        approval to full         Gas Industry, Dec. 17, 2021 (contained within
                                        approval).               the May 20, 2022 submittal).
Combustion equipment at major sources  Approval...............  Technical Support Document for Reasonably
                                                                 Available Control Technology for Major Sources,
                                                                 Dec. 14, 2020 (contained within the March 22,
                                                                 2021 submittal) and Technical Support Document
                                                                 for Reasonably Available Control Technology for
                                                                 Major Sources, July 16, 2021 (contained within
                                                                 the May 20, 2022 submittal).
Wood coating.........................  Approval...............  Technical Support Document for Reasonably
                                                                 Available Control Technology for Major Sources,
                                                                 Dec. 14, 2020 (contained within the March 22,
                                                                 2021 submittal).
Foam manufacturing...................  Approval...............  Technical Support Document for Reasonably
                                                                 Available Control Technology for Major Sources,
                                                                 Dec. 14, 2020 (contained within the March 22,
                                                                 2021 submittal).
----------------------------------------------------------------------------------------------------------------
Cited materials are contained within the docket for this action.

    We are proposing action on the RACT demonstrations for certain 
additional VOC CTG, non-CTG VOC, and NOX sources and 
categories. We have reviewed Colorado's new and revised VOC and 
NOX rules for the categories covered by the CTGs, and for 
major sources of non-CTG VOC and NOX sources for the 2008 8-
hour ozone NAAQS, and the demonstrations submitted by Colorado. Based 
on this review we propose to find that these rules are consistent with 
the control measures, definitions, recordkeeping, and test methods in 
these CTGs and the CAA, and that they satisfy CAA RACT requirements for 
the categories in question.\56\
---------------------------------------------------------------------------

    \56\ See https://www.epa.gov/ground-level-ozone-pollution/ract-information.
---------------------------------------------------------------------------

a. RACT for CTG Sources
    Table 3 contains the CTGs, EPA reference document, and the 
corresponding sections of Reg. 7 that fulfill the applicable RACT 
requirements for the EPA-issued CTGs. Colorado's Reg. 7 contains SIP 
approved and submitted revisions (see section V.I. of this document); 
we propose to find that these revisions meet RACT requirements for the 
sources listed in Table 3.

   Table 3--Sources, EPA CTG Reference Document, and Corresponding Sections of Reg. 7 Proposed for Approval to
                                                  Fulfill RACT
----------------------------------------------------------------------------------------------------------------
                                                                                             Reg. 7 sections
       Sources in the DMNFR area            CTG reference document        Date of CTG        fulfilling RACT
----------------------------------------------------------------------------------------------------------------
Oil and gas...........................  Control Techniques Guidelines             2016  part D, sections I, II,
                                         for the Oil and Natural Gas                     and III.
                                         Industry.
Miscellaneous Metal Coatings, Tables 2  Control Techniques Guidelines             2008  part C, section I.L.2.
 and 7 of the CTG.                       for Miscellaneous Metal and
                                         Plastic Parts Coatings.
----------------------------------------------------------------------------------------------------------------

    We have reviewed the emission limitations and control requirements 
for the above sources and compared them against the EPA's CTG documents 
and available technical information in CTG dockets. The EPA has also 
evaluated the submitted rules and has determined that they are 
consistent with the CAA, the EPA's regulations, and the EPA's policies. 
Based on the information in the record, we propose to find that the 
corresponding sections in Reg. 7 provide for the lowest emission 
limitation through application of control techniques that are 
reasonably available considering technological and economic 
feasibility. Therefore, we propose to find that the control 
requirements for oil and gas sources and certain miscellaneous metal 
coatings are RACT for affected sources in the DMNFR Area under the 2008 
8-hour ozone NAAQS.\57\
---------------------------------------------------------------------------

    \57\ For more information, see the EPA TSDs evaluating oil and 
gas and miscellaneous metal coatings RACT. Available within the 
docket for this action.
---------------------------------------------------------------------------

b. RACT for Non-CTG Major Sources
    In Colorado's TSDs for Reasonably Available Control Technology for 
Major Sources, dated December 14, 2020,\58\ Colorado identified a list 
of major non-CTG VOC and NOX sources in the DMNFR Area 
subject to RACT requirements under a Serious classification. For major 
VOC and NOX sources subject to nonattainment area RACT 
review, Colorado used the construction permit thresholds established in 
the State's Reg. 3 for determining which emission points to review. 
Accordingly, emission points exceeding two tpy of VOC at a major VOC 
source and five tpy of NOX at a major NOX source, 
as reported on a source's APEN, and that were not part of the Moderate 
RACT review, were evaluated. We have reviewed the State's March 22, 
2021 and May 20, 2022 submittals and find its approach to including 
these sources in the inventory acceptable. To satisfy the Serious RACT 
SIP requirement to establish RACT for all existing major sources of VOC 
and/or NOX in the DMNFR Area, the Commission incorporated by 
reference NSPS limits for combustion turbines, expanded the combustion 
equipment requirements for boilers, expanded wood furniture coating 
requirements, and developed a new categorical rule for foam 
manufacturing. These revisions were made based on a detailed review of 
available information on major NOX

[[Page 67624]]

and VOC sources in the DMNFR Area, an examination of the EPA RACT/Best 
Available Control Technology/Lowest Achievable Emission Rate 
Clearinghouse for similar emission points, and consideration of CAA 
section 182(b) RACT requirements for other ozone nonattainment areas. 
Table 4 contains a list of non-CTG categories, the EPA's reference 
documents, and the corresponding sections of Reg. 7 that are proposed 
for approval in this action to fulfill RACT requirements (see section 
V.I. of this document).\41\
---------------------------------------------------------------------------

    \58\ Contained within the March 22, 2021 submittal.

Table 4--Sources, EPA Reference Documents, and Corresponding Sections of
              Reg. 7 Proposed for Approval to Fulfill RACT
------------------------------------------------------------------------
                                  The EPA's reference
   Source in the DMNFR area     document or regulation   Reg. 7 sections
                                    (if applicable)      fulfilling RACT
------------------------------------------------------------------------
Combustion turbines...........  X Emissions from        part E, section
                                 Stationary Combustion   II.
                                 Turbines (EPA-453/3-
                                 91-026) (1991).
Process heaters...............  NOX Emissions from      part E, section
                                 Process Heaters (EPA-   II.
                                 453/R-93-034)(1993).
Combustion equipment            NOX Emissions from      part E, section
 requirements for boilers.       Industrial,             II.
                                 Commercial &
                                 Institutional Boilers
                                 (EPA-453/R-94-
                                 022)(1994).
Wood furniture coating          A Guide to the Wood     part C, section
 requirements.                   Furniture CTG and       I.O.
                                 NESHAP (EPA-453/R-97-
                                 002) (1997).
Foam manufacturing............  ......................  part E, section
                                                         V.
------------------------------------------------------------------------

    We have reviewed the emission limitations and control requirements 
for the source categories in Table 4 and compared them to the EPA's 
regulations, ACT documents, available technical information, and 
guidelines. The EPA has also evaluated the submitted rules and has 
determined that they are consistent with the CAA, the EPA's 
regulations, and the EPA's policies. For more information, see the EPA 
TSD prepared in conjunction with this action. Based on the information 
in the record, we propose to find that the corresponding sections in 
Reg. 7 provide for the lowest emission limitation through application 
of control techniques that are reasonably available considering 
technological and economic feasibility. Therefore, we propose to find 
that the control requirements for the source categories identified in 
Table 4 are RACT for all affected sources in the DMNFR Area under the 
2008 8-hour ozone NAAQS.
c. Negative Declarations
    States are not required to adopt RACT limits for source categories 
for which no sources exist in a nonattainment area, and can submit a 
negative declaration to that effect. The EPA approved the majority of 
the State's negative declarations on July 3, 2018.\59\ In its 2008 
Serious OAP, Colorado reevaluated the CTGs and determined that it does 
not have sources in the following CTG VOC categories or subject to the 
potentially applicable CTG within the DMNFR Area that are listed in 
Table 5. We are also unaware of any such facilities operating in the 
Area, and thus we propose to approve the negative declarations made for 
the CTG categories in Table 5 for the DMNFR Area under the 2008 8-hour 
ozone NAAQS.
---------------------------------------------------------------------------

    \59\ See 83 FR 31068. A negative declaration for the aerospace 
CTG was approved on November 5, 2021 (86 FR 61071).

          Table 5--Negative Declarations for CTG VOC Categories
------------------------------------------------------------------------
 
-------------------------------------------------------------------------
Auto and Light-Duty Truck Assembly Coatings (2008).
Coating Operations at Aerospace Manufacturing and Rework Operations
 (1994).
Factory Surface Coating of Flat Wood Paneling.
Fiberglass Boat Manufacturing Materials (2008).
Flat Wood Paneling Coatings (2006).
Flexible Packaging Printing Materials (2006).
Fugitive Emissions from Synthetic Organic Chemical Polymer and Resin
 Manufacturing Equipment (1984).
Graphic Arts--Rotogravure and Flexography (1978).
Large Appliance Coatings (2007).
Large Petroleum Dry Cleaners (1982).
Manufacture of High-Density Polyethylene, Polypropylene, and Polystyrene
 Resins.
Manufacture of Pneumatic Rubber Tires (1972).
Miscellaneous Industrial Adhesives (2008).
Plastic Parts Coatings, Tables 3, 4, 8, and 9 of the CTG (2008).
Synthetic Organic Chemical Manufacturing Air Oxidation Processes (1984).
Synthetic Organic Chemical Manufacturing Distillation and Reactor
 Processes (1993).
Surface Coating for Insulation of Magnet Wire (1977).
Shipbuilding/repair (1996).
Surface Coating of Automobiles and Light Duty Trucks (1977).
Surface Coating of Fabrics (1977).
Surface Coating of Large Appliances (1977).
Surface Coating of Paper (2007).
------------------------------------------------------------------------

D. Reasonably Available Control Measures (RACM) Analysis

1. Background
    CAA section 172(c)(1) of the CAA requires that states adopt ``all 
reasonably available control measures [RACM] as expeditiously as 
practicable.'' The EPA interprets the CAA RACM provision to require a 
demonstration that: (1) The state has adopted all reasonable measures 
(including RACT) to meet RFP requirements and to demonstrate attainment 
as expeditiously as possible; and (2) no additional measures that are 
reasonably available will advance the attainment date or contribute to 
RFP for the area.\60\ States should consider all available measures, 
including those being implemented in other areas, but must adopt 
measures for an area only if those measures are economically and 
technologically feasible and will advance the attainment date or are 
necessary for RFP.\61\ Potentially available measures that would not 
advance the attainment date for an area are not considered RACM; 
likewise, states can reject potential RACM if adopting them would cause 
substantial widespread and long-term adverse impacts.\62\ Local 
conditions, such as economic or implementation concerns, may also be 
considered. To allow the EPA to determine whether the RACM requirement 
has been satisfied, states

[[Page 67625]]

should discuss in the SIP submittals whether measures ``within the 
arena of potentially reasonable measures'' are in fact reasonably 
available.\63\ If the measures are reasonably available, they must be 
adopted as RACM.
---------------------------------------------------------------------------

    \60\ 40 CFR 51.912(d); Final Rule To Implement the 8-Hour Ozone 
National Ambient Air Quality Standard--Phase 2, 70 FR 71612, 71659 
(Nov. 29, 2005). See also General Preamble, State Implementation 
Plans; General Preamble for the Implementation of title I of the 
Clean Air Act Amendments of 1990, 57 FR 13498, 13560 (April 16, 
1992).
    \61\ 80 FR 12264, 12282 (March 6, 2015).
    \62\ Id.
    \63\ ``Guidance on the Reasonably Available Control Measures 
(RACM) Requirement and Attainment Demonstration Submissions for 
Ozone Nonattainment Areas,'' John S. Seitz, Director, Office of Air 
Quality Planning and Standards, EPA (Nov. 30, 1999).
---------------------------------------------------------------------------

2. Evaluation
    Colorado previously evaluated potentially available control 
measures for RACM purposes with their 2008 Moderate ozone attainment 
plan. The EPA approved the State's RACM analysis on July 3, 2018.\64\ 
The RAQC resumed RACM discussions with the CDPHE and other partners in 
2018 when the DMNFR Area was reclassified to Serious, so as to identify 
strategies that would help the Area attain by the 2020 ozone 
season.\65\ Areas of analysis included stationary and area sources, 
mobile sources and fuels, transportation, land use, pricing, and 
outreach. Subcommittee meetings were open to the public, and 
stakeholders provided input on the topics discussed.
---------------------------------------------------------------------------

    \64\ See 83 FR 31068.
    \65\ See p. 7-3 of the OAP.
---------------------------------------------------------------------------

    The State's RACM review took place in the context of a series of 
state actions that had the effect of reducing emissions. Since the base 
year of 2011, Colorado has adopted oil and gas regulations; \66\ 
implemented controls required under the State Clean Air Clean Jobs Act 
\67\ through the Regional Haze SIP; and continued alternative 
fuels,\68\ transportation,\69\ and land use programs.\70\ Additional 
efforts include the ongoing work of the Statewide Hydrocarbon Emissions 
Reduction Team and Pneumatics Task Force, and numerous bills aimed at 
improving air quality.\71\
---------------------------------------------------------------------------

    \66\ Colorado Reg. 7, part D.
    \67\ Colo. Rev. Stat. section 40-3.2-201 et seq.
    \68\ E.g., fueling and charging station grants.
    \69\ E.g., Programs for improved public transit.
    \70\ E.g., example, Denver Regional Council of Governments 
identified urban growth area.
    \71\ See p. 7-3 of the OAP.
---------------------------------------------------------------------------

    As part of the RACM analysis, CDPHE examined emission reduction 
measures \72\ being implemented in the DMNFR Area that are not included 
in the SIP modeling and emissions inventory because they are voluntary 
or difficult to quantify. Non-federally enforceable emission reduction 
measures were evaluated for stationary and mobile sources, lawn and 
garden equipment, and the transportation system; outreach and education 
were also evaluated as part of this analysis. Additionally, Colorado 
evaluated CAA 108(f), transportation measures \73\ to determine whether 
sources have applied RACM.
---------------------------------------------------------------------------

    \72\ See Table 48 of the OAP.
    \73\ See Table 52 of the OAP.
---------------------------------------------------------------------------

    After reviewing possible measures, Colorado determined that all 
reasonably available control measures necessary to demonstrate 
attainment are currently being implemented. Table 47 of Colorado's OAP 
lists control measures included in Colorado's SIP as they relate to the 
State's 2017 and 2020 emission inventories, photochemical modeling in 
the attainment demonstration, and weight of evidence analysis.
    Emission measures that were evaluated but determined not to be RACM 
are discussed in chapter 7.5 of the OAP. Colorado used the following 
criteria to determine whether measures were considered RACM:
     Necessary to demonstrate attainment;
     Technologically or economically feasible;
     Implemented successfully in other Serious nonattainment 
areas;
     Could be implemented by May 1, 2020; and
     Could qualify as SIP measures by being quantifiable, 
enforceable, permanent, and surplus.
    Emission reduction measures evaluated for RACM were broken into 
various categories: oil and gas, mobile source inspection and 
maintenance, fuels, transportation, local government policies, 
outreach, land use, and other. Table 54 of the OAP summarizes the 
measures evaluated and Colorado's RACM determination for each measure. 
Colorado also reviewed the EPA's Menu of Control Measures for NAAQS 
Implementation \74\ and voluntary and mandatory control measures in 
other ozone nonattainment areas. Table 55 of the OAP lists control 
measures identified, and indicates which measures were included in the 
State's RACM review. Although Colorado's analysis demonstrated that 
none of the additional measures identified met the criteria for RACM, 
the State plans to continue evaluating strategies in various areas, 
including oil and gas, mobile source inspection and maintenance, fuels, 
transportation, and local government policies, as described in Table 54 
of the OAP.
---------------------------------------------------------------------------

    \74\ The Menu of Control Measures gives state, local and tribal 
air agencies information on existing emissions reduction measures, 
as well as relevant information concerning the efficiency and cost 
effectiveness of the measures. Available at https://www.epa.gov/air-quality-implementation-plans/menu-control-measures-naaqs-implementation.
---------------------------------------------------------------------------

    In its analysis, Colorado evaluated all source categories that 
could contribute meaningful emission reductions, and identified and 
evaluated an extensive list of potential control measures. To determine 
reasonableness and availability, the State considered the time needed 
to develop and adopt regulations, and the time it would take to see the 
benefit from these measures. The EPA has reviewed the RACM analysis and 
finds that there are no additional RACM that would have advanced the 
Serious area attainment date of 2021 for the DMNFR Area.\75\ Therefore, 
the EPA proposes to approve Colorado's Serious area RACM analysis for 
the DMNFR Serious nonattainment area.
---------------------------------------------------------------------------

    \75\ On October 7, 2022 the EPA finalized an action that among 
other things 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 will be required to submit a 
demonstration that the area will attain the Severe standard, and 
other elements of a Severe SIP.
---------------------------------------------------------------------------

E. Motor Vehicle Inspection and Maintenance Program (I/M) Program

1. Background
    As a Serious ozone nonattainment area, pursuant to CAA section 
182(c)(3), Colorado was required to implement an enhanced I/M program 
in the DMNFR Area.\76\ Colorado's Regulation Number 11 (Reg. 11) is 
titled ``Motor Vehicle Emissions Inspection Program,'' and addresses 
the implementation of the State's I/M program.\77\ Under Reg. 11 and 
other state law,\78\ all eligible automobiles registered in the 
Automobile Inspection and Readjustment (AIR) program area \79\ are 
subject to periodic emissions inspection. Currently there is an 
exemption from emissions inspection requirements for the first seven 
model years. Thereafter, an On-Board-Diagnostics (OBD) vehicle computer 
inspection is conducted during the first two inspection cycles 
(vehicles 8 through 11 model years old). Vehicles older than 11 model 
years are given a dynamometer-based IM240 test for 1982 and newer 
light-duty gasoline vehicles \80\ and a two-speed idle test

[[Page 67626]]

(TSI) \81\ for 1981 and older light-duty gasoline vehicles. To improve 
motorist convenience and reduce program implementation costs, the State 
also administers a remote sensing-based ``Clean Screen'' program 
component of the I/M program. Remote sensing is a method for measuring 
vehicle emissions, while simultaneously photographing the license 
plate, when a vehicle passes through infrared or ultraviolet beams of 
light. Owners of vehicles meeting the Clean Screen criteria are 
notified by the respective County Clerk that their vehicle has passed 
the motor vehicle inspection process and are exempt from their next 
regularly scheduled program inspection.\82\
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    \76\ 5 CCR 1001-13.
    \77\ The provisions which have been approved by the EPA into the 
Colorado SIP via past rulemaking actions, including Reg. 11, are 
publicly available at https://www.epa.gov/sips-co/epa-approved-statutes-and-regulations-colorado-sip.
    \78\ CO Rev Stat section 42-4-304 (2016).
    \79\ The current nine-county AIR program area is depicted in 
chapter 8, figure 19, page 8-3 of the OAP.
    \80\ See 40 CFR part 51, subpart S for a complete description of 
EPA's IM240 test. The IM240 test is essentially an enhanced motor 
vehicle emissions test to measure mass tailpipe emissions while the 
vehicle follows a computer-generated driving cycle trace for 240 
seconds and while the vehicle is on a dynamometer.
    \81\ See 40 CFR part 51, subpart S for a complete description of 
EPA's two-speed idle test. The two-speed idle test essentially 
measures the mass tailpipe emissions of a stationary vehicle; one 
reading is at a normal idle of approximately 700 to 800 engine 
revolutions per minute (RPM) and one reading at 2,500 RPM.
    \82\ The Clean Screen program component of Reg. 11 was 
originally approved for implementation in the Denver area with the 
EPA's approval of the original Denver carbon monoxide (CO) 
redesignation to attainment and the related maintenance plan. See 66 
FR 64751 (Dec. 14, 2001). The Clean Screen criteria approved in 2001 
required two valid passing remote sensing readings, on different 
days or from different sensors and within the twelve-month period 
prior to that vehicle's registration renewal date. Colorado revised 
Reg. 11 to expand the definition and requirements for a ``clean-
screened vehicle'' to also include vehicles identified as low-
emitting vehicles in the state-determined Low Emitting Index (LEI) 
that have one passing remote sensing reading, before the vehicle's 
registration renewal date. These improvements and other associated 
revisions to the Clean Screen program were approved by the EPA on 
October 21, 2016 (81 FR 72720).
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2. Evaluation
    The AIR program and Reg. 11 were expanded into portions of Larimer 
and Weld counties as ``state only'' requirements in the Colorado 2009 
Legislative session, with the passage of Senate Bill 09-003. The 
startup date of the I/M program in these two counties was November 1, 
2010. The purpose of this expansion of the AIR program and Reg. 11 into 
portions of Larimer and Weld counties was to further reduce vehicle 
emissions of NOX and VOC ozone precursors in the 2008 DMNFR 
Area. With the reclassification of the DMNFR Area to Moderate for the 
2008 8-hour ozone NAAQS, and in light of the associated CAA 
requirements, the State chose to submit the I/M program in Larimer and 
Weld counties into the SIP. Accordingly, as part of Moderate Area SIP 
revisions for the 2008 8-hour ozone NAAQS, Colorado removed the 
Larimer/Weld ``state-only'' designation in Reg. 11 and submitted a 
revised Reg. 11 to the EPA, which was approved July 3, 2018.\83\
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    \83\ 83 FR 31068.
---------------------------------------------------------------------------

    The most recent federally approved revisions to the Reg. 11 
enhanced I/M program were adopted by the AQCC in May 2017. The 
revisions consisted of:
     Inclusion of OBD I/M pass/fail results as a qualifying 
consideration in the remote sensing clean screen low emitter index,
     Clarification of details of tailpipe and OBD inspection 
procedures and OBD readiness criteria, and
     Establishing authority to fail vehicles exhibiting 
evidence of OBD fraud.
    These revisions were approved by EPA on February 7, 2019.\84\
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    \84\ 84 FR 2449. Colorado submitted the latest revisions to Reg. 
11 to the EPA on May 16, 2022. The EPA will act on those revisions 
in a separate action. Since these most recent changes to Reg. 11 
were adopted by the State after the attainment date for Serious 
areas under the 2008 ozone NAAQS, the revisions were not considered 
when evaluating the adequacy of Colorado's enhanced I/M program in 
the context of this current EPA action.
---------------------------------------------------------------------------

    On July 15, 2022, Colorado submitted supplemental modeling of the 
State's I/M program for comparison against the applicable Enhanced I/M 
performance standard requirements in 40 CFR part 51, subpart S. 
Colorado used the latest approved version of the EPA's mobile source 
emissions model, MOVES3.0.3 (released January 2022), for the 
comparative analysis. Demonstration of program equivalency to the 
enhanced I/M program standard was conducted in accordance with the 
EPA's published I/M performance standard modeling guidance, MOVES3 
technical guidance, and additional technical guidance from the EPA as 
necessary.\85\
---------------------------------------------------------------------------

    \85\ See Performance Standard Modeling for New and Existing 
Vehicle Inspection and Maintenance (I/M) Programs Using the MOVES 
Mobile Source Emissions Model, EPA-420-B-14-006 (Jan. 2014), 
available at http://nepis.epa.gov/Exe/ZyPdf.cgi?Dockey=P100HHMP.pdf; 
MOVES3 Technical Guidance: Using MOVES to Prepare Emission 
Inventories for State Implementation Plans and Transportation 
Conformity, EPA-420-B-20-052 (Nov. 2020), available at https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1010LY2.pdf.
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    To demonstrate that the Colorado enhanced I/M program meets the 
enhanced program performance standard described in 40 CFR 51.351(i), 
the Colorado program must be modeled to show that, on the proper 
analysis date, it obtains the same or lower emissions reductions as the 
federal model enhanced program. The state program may provide 
reductions of NAAQS relevant pollutants equivalent to the reductions 
expected from the model program to within 0.02 grams per 
mile for the area's total vehicle miles travelled on a July weekday in 
the attainment date year. Colorado's supplemental demonstration shows 
that the state's I/M program meets the applicable enhanced I/M 
performance standard requirements for the 2008 ozone NAAQS.
    Based on our review and as discussed above we find that Colorado 
has a Vehicle I/M Program that meets the performance standard for 
Enhanced I/M, and we therefore propose approval of this portion of the 
OAP.

F. Nonattainment New Source Review (NNSR)

1. Background
    As a Serious ozone nonattainment area, Colorado was required to 
implement an NNSR program. Applicable NNSR requirements for ozone 
nonattainment areas are described in CAA section 182 and further 
defined in 40 CFR part 51, subpart I (Review of New Sources and 
Modifications). Under these requirements, new major sources and major 
modifications at existing sources must achieve the lowest achievable 
emission rate (LAER) and obtain emission offsets in an amount based on 
the specific ozone nonattainment classification. The emission offset 
ratio required for Serious ozone nonattainment areas is 1.2 to 1.\86\
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    \86\ CAA section 182(c)(10).
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2. Evaluation
    The Colorado SIP includes Regulation 3, part D, section V.A. 
(Concerning Major Stationary Source New Source Review and Prevention of 
Significant Deterioration, Requirements Applicable to Nonattainment 
Areas).\87\ This provision requires new major sources and major 
modifications at existing sources in the DMNFR Area to comply with LAER 
and obtain emission offsets at the Serious classification ratio of 1.2 
to 1. The EPA approved these provisions on January 25, 2016.\88\ Since 
the provisions in the Colorado SIP satisfy the CAA NNSR requirements 
for ozone nonattainment areas classified as Serious, we propose 
approval of this portion of the OAP.
---------------------------------------------------------------------------

    \87\ The provisions which have been approved by the EPA into the 
Colorado SIP via past rulemaking actions, including Regulation 
Number 3, are publicly available at https://www.epa.gov/sips-co/epa-approved-statutes-and-regulations-colorado-sip.
    \88\ 81 FR 3963.

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[[Page 67627]]

G. Motor Vehicle Emissions Budget (MVEB)/Transportation Conformity

1. Background
    Section 176(c) of the CAA establishes a requirement known as 
``Transportation Conformity,'' under which federal agencies must ensure 
that actions they support or fund will conform to the applicable SIP. 
Conformity to a SIP means that transportation activities will not 
produce new air quality violations, worsen existing violations, or 
delay timely attainment of the NAAQS.\89\ The EPA's conformity rule at 
40 CFR part 93, subpart A requires that transportation plans, programs, 
and projects conform to SIPs, and establishes the criteria and 
procedures for determining whether they conform. The conformity rule 
requires a demonstration that emissions from the Metropolitan Planning 
Organization's (MPO) Regional Transportation Plan (RTP) and the 
Transportation Improvement Program (TIP) are consistent with the MVEB 
in the control strategy SIP revision or maintenance plan.\90\ The MVEBs 
are defined as the portion allocated to mobile source emissions out of 
the total allowable emissions of a pollutant defined in the SIP for a 
certain date for the purpose of demonstrating attainment or maintenance 
of the NAAQS or for meeting RFP milestones.\91\
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    \89\ CAA section 176(c)(1)(B).
    \90\ 40 CFR 93.101, 93.118, and 93.124.
    \91\ 40 CFR 93.101; see 40 CFR 93.118 and 93.124 for criteria 
and other requirements related to MVEBs. Further discussion of MVEBs 
is in the preamble to the transportation conformity rule. 58 FR 
62188, 62193-62196 (Nov. 24, 1993).
---------------------------------------------------------------------------

    Additionally, CAA section 182(c)(5) requires that states, every 
three years, submit a demonstration for Serious nonattainment areas 
that current aggregate VMT, aggregate vehicle emissions, congestion 
levels, and other relevant traffic-related and vehicle emissions-
related factors (collectively ``relevant parameters'') are consistent 
with those used for the area's ozone attainment demonstration.
2. Evaluation
    Colorado derived the MVEBs for NOX and VOCs from its 
2020 DMNFR Serious attainment demonstration, and defined the MVEBs in 
chapter 11, section 11.2.1 of the OAP.

             Table 6--2020 NOX and VOC MVEBs for DMNFR Area
------------------------------------------------------------------------
                                             2020 NOX        2020 VOC
          Area of applicability              emissions       emissions
                                               (tpd)           (tpd)
------------------------------------------------------------------------
Northern Subarea........................             9.7             8.2
Southern Subarea........................              45            41.2
Total Nonattainment Area................            54.7            49.4
------------------------------------------------------------------------

    These MVEBs are consistent with, and clearly related to, the 
emissions inventory and the control measures in the SIP, and satisfy 
the criteria at 40 CFR 93.118(e)(4). Therefore, we propose approval of 
the MVEBs as reflected in Table 6. This proposed approval applies to 
the Northern Subarea and Southern Subarea MVEBs as well as the Total 
Nonattainment Area MVEBs. The transportation conformity subareas are 
defined in chapter 11, section 11.2 of the OAP and are listed below.
     The Northern Subarea is the area denoted by the ozone 
nonattainment area north of the Boulder County northern boundary and 
extended through southern Weld County to the Morgan County line. This 
area includes the North Front Range MPO's (NFRMPO) regional planning 
area as well as part of the Upper Front Range Transportation Planning 
Region (TPR) in Larimer and Weld counties.
     The Southern Subarea is the area denoted by the ozone 
nonattainment area south of the Boulder County northern boundary and 
extended through southern Weld County to the Morgan County line. This 
area includes the nonattainment portion of the Denver Regional Council 
of Governments (DRCOG) regional planning area and the southern Weld 
County portion of the Upper Front Range TPR.
     Both subareas are further described in the OAP in Figure 
20, ``8-hour Ozone Nonattainment Area Subareas.''
    In addition to proposing approval of the MVEBs, we also propose to 
approve the process described in chapter 11, section 11.2.3 in the OAP 
for the use of the Total Nonattainment Area MVEBs or the subarea MVEBs 
for the respective MPOs to determine transportation conformity for 
their respective RTP. As described in section 11.2.3 of Colorado's OAP, 
the OAP identifies subarea MVEBs for DRCOG and the NFRMPO. These SIP-
identified subarea MVEBs allow either MPO to make independent 
conformity determinations for the applicable subarea MVEBs whose 
frequency and timing needs for conformity determinations differ. As 
noted in section 11.2.3, DRCOG and the NFRMPO may switch from using the 
Total Nonattainment Area MVEBs to using the subarea MVEBs for 
determining conformity. To switch to use of the subarea MVEBs (or to 
subsequently switch back to use of the Total Nonattainment Area MVEBs) 
DRCOG and the NFRMPO must use the process described in the DMNFR OAP in 
section 11.2.3.\92\ This process of demonstrating transportation 
conformity to the total or subarea area MVEBs, as described in section 
11.2.3 of the OAP, was previously approved by the EPA for the Denver 
Moderate Ozone Plan for the 2008 8-hour standard on July 3, 2018.\93\ 
Now, as to the Serious classification for the 2008 8-hour standard, the 
EPA finds that this process remains consistent with the CAA and with 
applicable EPA regulations, and therefore proposes to approve it.
---------------------------------------------------------------------------

    \92\ See pp. 11-5 and 11-6 of the OAP.
    \93\ 83 FR 31068.
---------------------------------------------------------------------------

    Regarding transportation control requirements, as described in 
section 11.3 of the OAP, MVEBs are evaluated on a regular basis by the 
MPOs through their conformity process. Based on the most recent 
conformity determinations for the northern and the southern subregions, 
Colorado's demonstration shows that both areas were meeting the current 
emissions budgets established in the 2008 Moderate area Ozone SIP, and 
that they are expected be able to meet the proposed budgets for the 
2008 Serious area Ozone SIP in future conformity determinations. The 
EPA finds that the transportation control measures as described in 
section 11.3 of the OAP meet CAA requirements. We therefore propose to 
approve this section of the OAP.

[[Page 67628]]

H. Clean Fuel Fleet Program

1. Background
    Sections 182(c)(4) and 241-246 of the CAA provide that states with 
ozone nonattainment areas classified as Serious, Severe, or Extreme 
must implement a federally enforceable program to require certain 
centrally fueled fleet operators to include a specified percentage of 
clean-fuel vehicles (CFV) in their new fleet purchases to reduce 
emissions of ozone precursors, or else to engage in a state-managed 
credit trading scheme with other fleet operators who purchase CFV in 
excess to requirements. Section 182(c)(4) of the Act also allows states 
subject to the clean-fuel fleet program requirements to develop 
substitute programs to achieve equivalent reductions to those achieved 
by the default program requirements for the covered nonattainment area, 
and to submit them to the EPA for approval.\94\
---------------------------------------------------------------------------

    \94\ Final rule, Emission Standards for Clean-Fuel Vehicles and 
Engines, Requirements for Clean-Fuel Vehicle Conversions, and 
California Pilot Test Program, 59 FR 50042 (Sept. 30, 1994).
---------------------------------------------------------------------------

2. Evaluation
    In the OAP, Colorado cited an EPA determination \95\ that, 
beginning with the 2007 model years, both the Tier 2 conventional 
vehicle and engine standards and heavy-duty vehicle and engine 
standards are either equivalent to or more stringent than the 
applicable clean fuel vehicle program low emission vehicle (LEV) 
standards. Table 59 of the OAP includes a clean fuel fleet emission 
comparison demonstrating that Tier 2 and 2004 heavy-duty engine 
standards are equivalent or more stringent than the Clean Fuel Fleet 
standards and that the emission reductions from the federal standards 
surpassed LEV emission reductions in 2004, when the federal standards 
were implemented. Additionally, figure 23 of the OAP provides a 
comparison of Tier 3 Motor Vehicle Emission and Fuel Standards program 
that illustrates even larger emission reductions over CFV standards.
---------------------------------------------------------------------------

    \95\ See EPA Dear Manufacturer Letter CCD-05 (LDV/LDT/MDPV/HDV/
HDE/LD-FC), July 21, 2005, in the docket for this rulemaking.
---------------------------------------------------------------------------

    The EPA amended the Clean Fuel Fleet standards in 40 CFR part 88 in 
2021 to address the fact that current emissions standards for engines 
and vehicles are either more stringent than or equivalent to the Clean 
Fuel Fleet standards.\96\ According to these amendments, all new fleet 
purchases of vehicles and engines certified to current emission 
standards are deemed to meet the Clean Fuel Fleet standards as Ultra 
Low-Emission Vehicles.
---------------------------------------------------------------------------

    \96\ Final rule, Improvements for Heavy-Duty Engine and Vehicle 
Test Procedures, and Other Technical Amendments 86 FR 34308 (June 
29, 2021).
---------------------------------------------------------------------------

    Because 2004 model year Heavy Duty Diesel and Tier II and III 
vehicle standards meet or exceed the CFV LEV standards, we propose to 
find that Colorado meets the Federal Clean Fuel Fleet Program 
requirements, and to approve that portion of the submittal that 
addresses the requirements of section 182(c)(4) of the CAA.

I. SIP Control Measures

1. Background
    This section describes revisions to Colorado Regs. 7 and 21 
submitted as a part of the SIP, including emission control requirements 
for oil and gas operations; turbines, process heaters, and other 
combustion equipment, foam manufacturing; architectural coatings and 
consumer products. The revisions also establish RACT requirements for 
emission points at certain CTGs and major sources of VOC and 
NOX in the DMNFR Area.
    Colorado's Reg. 7, entitled ``Control of Ozone via Ozone Precursors 
and Control of Hydrocarbons via Oil and Gas Emissions,'' contains 
general RACT requirements as well as specific emission limits 
applicable to various industries. The EPA approved the repeal and re-
promulgation of Reg. 7 in 1981,\97\ and has approved various revisions 
to Reg. 7 over the years. In 2008, the EPA approved revisions to the 
control requirements for condensate storage tanks in section XII,\98\ 
and later approved revisions to Reg. 7, sections I through XI and 
sections XIII through XVI.\99\ The EPA also approved Reg. 7 revisions 
to section XVII.E.3.a establishing control requirements for rich-burn 
reciprocating internal combustion engines.\100\ In 2018 the EPA 
approved Reg. 7 revisions in sections XII (VOC emissions from oil and 
gas operations) and XIII (emission control requirements for VOC 
emissions from graphic art and printing processes), as well as non-
substantive revisions to numerous other parts of the regulation.\101\
---------------------------------------------------------------------------

    \97\ Final rule, Colorado: Approval and Promulgation of State 
Implementation Plans, 46 FR 16687 (March 13, 1981).
    \98\ Final rule, Approval and Promulgation of Air Quality 
Implementation Plans; State of Colorado; Regulation No. 7, section 
XII, Volatile Organic Compounds From Oil and Gas Operations, 73 FR 
8194 (Feb. 13, 2008).
    \99\ Final rule, Approval and Promulgation of State 
Implementation Plans; State of Colorado; Attainment Demonstration 
for the 1997 8-Hour Ozone Standard, and Approval of Related 
Revisions, 76 FR 47443 (Aug. 5, 2011).
    \100\ Final rule, Approval and Promulgation of Implementation 
Plans; State of Colorado; Regional Haze State Implementation Plan, 
77 FR 76871 (Dec. 31, 2012).
    \101\ See 83 FR 31068, 31071.
---------------------------------------------------------------------------

    In February 2021, the EPA approved Reg. 7 revisions in sections I 
(Applicability), IX (Surface Coating Operations), X (Use of Cleaning 
Solvents), XIII (Graphics Arts and Printing), XVI (Controls of 
Emissions from Stationary and Portable Engines and Other Combustion 
Equipment in the 8-Hour Ozone Control Area), and XIX (Control of 
Emissions from Specific Major Sources of VOC and/or NOX in 
the 8-hour Ozone Control Area). Revisions to incorporation by reference 
dates to rules and reference methods in sections II, VI, VIII, IX, X, 
XII, XIII, XVI and XVII were also approved, as well as non-substantive 
revisions to numerous other parts of the regulation.\102\
---------------------------------------------------------------------------

    \102\ 86 FR 11125.
---------------------------------------------------------------------------

    In November 2021, the EPA approved submitted revisions to sections 
II (general provisions), XII (Volatile Organic Compound Emissions from 
Oil and Gas Operations), and XVIII (emissions from natural gas-actuated 
pneumatic controllers located at or upstream of natural gas processing 
plants) of Reg. 7 from State submissions in 2018 and 2019.\103\ From 
the State's 2020 submission, the EPA approved revisions that fully 
reorganized Reg. 7. into parts A-E; updated requirements for gasoline 
transport trucks, bulk terminals, and service stations in part B; added 
general solvent use requirements in part C, section II.F; and added 
stationary internal combustion engine and flare RACT requirements for 
major sources of VOC and/or NOX in the Denver Area in part 
E. Revisions to incorporation by reference dates to rules, updates to 
reference methods, and typographical, grammatical and formatting 
corrections were made throughout Reg. 7. Additionally, the EPA 
finalized approval of the State's negative declaration--(that is, its 
statement that there are no covered sources in the DMNFR Area) as to 
the aerospace CTG.
---------------------------------------------------------------------------

    \103\ 86 FR 61071.
---------------------------------------------------------------------------

    Most recently, in May 2022, the EPA conditionally approved AQCC 
regulations of ozone precursor and hydrocarbon emissions from oil and 
gas operations in sections XII.J.1 of Reg. 7 from the State's May 14, 
2018 submittal and part D, sections I.D., I.E., I.F., and I.J.1. of 
Reg. 7 from the State's May 13, 2020 submission.\104\ Additionally, the 
EPA conditionally approved Colorado's determination that Reg. 7, part D 
satisfies RACT requirements for the

[[Page 67629]]

Colorado ozone SIP for the 2016 oil and natural gas CTG.
---------------------------------------------------------------------------

    \104\ 87 FR 29228 (May 13, 2022).
---------------------------------------------------------------------------

    Colorado submitted new regulation number 21 (Reg. 21) on May 13, 
2020, and revised Reg. 7 revisions with the OAP on March 22, 2021, and 
subsequent revisions on May 18, 2021 and May 20, 2022. The 2020 
submittal includes new Reg. 21, which establishes VOC content limits in 
architectural coatings and consumer products. The 2022 revisions in 
Reg. 7, part C, section I.O and part E, sections II.A., III.B., and V. 
address RACT for major sources with VOC and/or NOX emissions 
equal to or greater than 50 tpy; specifically, for wood surface 
coatings operations, boilers, turbines, process heaters, landfill gas 
and biogas fired engines,\105\ and foam manufacturing. The 2021 
submittals include revisions to Reg. 7, part D, sections I.E.3., 
I.J.1., and III.B to address oil and gas CTG requirements, and clerical 
revisions in parts C, sections I.A., I.L., and E, sections II.A. 
Colorado made substantive SIP revisions to Reg. 21 and certain limited 
parts of Reg. 7, particularly part C, sections I.O. and I.L.; part D, 
sections I.E.3. and I.J.1; and part E, sections, II.A.1.c., II.A.3.p, 
II.A.4.b.(i), II.A.4.b.(iv), II.A.4.f., II.A.4.g, II.A.5.a.(iii), 
II.A.5.b.(ii)(B), II.A.5.b.(ii)(B), II.A.5.b.(ii)(C)(4), 
II.A.5.c.(i)(A), II.A.6.b.(viii)(E), and V. The State also made non-
substantive revisions to numerous parts of Reg. 7. For ease of review, 
Colorado submitted the full text of Reg. 7 and Reg. 21 as a SIP 
revision (with the exception of provisions designated ``State Only''). 
The EPA is only seeking comment on Colorado's proposed substantive 
changes to the SIP-approved version of Reg. 7, which are described 
below. We are not seeking comment on incorporation into the SIP of the 
revised portions of the regulation that were previously approved into 
the SIP and have not been substantively modified by the State as part 
of this submission.
---------------------------------------------------------------------------

    \105\ The EPA will be acting on the State's RACT determination 
for landfill and biogas fired engines in a separate action.
---------------------------------------------------------------------------

    As noted above, Colorado designated various parts of Reg. 7 and 
Reg. 21 ``State Only'' and in Reg. 7, section I.A.1.c and Reg. 21, 
section I.A.2. indicated that sections designated State Only are not 
federally enforceable. The EPA concludes that provisions designated 
State Only have not been submitted for EPA approval, but for 
informational purposes. Hence, the EPA is not proposing to act on the 
portions of Regs. 7 or 21 designated State Only, and this proposed rule 
does not discuss them further except as relevant to discussion of the 
portions of the regulation that Colorado intended to be federally 
enforceable.
2. Evaluation
a. Analysis of Reg. 21 Changes in May 13, 2020 Submittal
    The EPA proposes to approve the changes made to Reg. 21 with 
Colorado's May 13, 2020 submission.
(i) Part A
    Part A of Reg. 21 establishes new rules for limiting VOC emissions 
from consumer products as of May 1, 2020. ``Consumer products,'' as 
defined in section VI.GG., ``means a chemically formulated product used 
by household and institutional consumers including, but not limited to, 
detergents; cleaning compounds; polishes; floor finishes; cosmetics; 
personal care products; home, lawn, and garden products; disinfectants; 
sanitizers; aerosol paints; automotive specialty products; and aerosol 
adhesives. Consumer product does not include other paint products, 
furniture coatings, or architectural coatings.'' \106\ Section I 
contains the applicability requirements. The rules apply to people who 
sell, supply, offer for sale, distribute for sale, or manufacture for 
sale consumer products in the 8-hour ozone control area. Section I.B. 
includes a number of exemptions from the requirements in section A, 
such exemptions for consumer products that are manufactured in Colorado 
solely for shipment and use outside of Colorado, and for consumer 
products that have been granted an Innovative Product exemption, an 
Alternative Control Plan (ACP), or a variance under the Variances 
provisions by the California Air Resources Board (CARB).
---------------------------------------------------------------------------

    \106\ See p. 260 of the May 13, 2020 submittal.
---------------------------------------------------------------------------

    Table 1 in section II establishes VOC content limits for 
manufacturing, selling, suppling, offering for sale, and distributing 
consumer products. Additional standards in section II include labeling, 
certification, and VOC limit applicability requirements for consumer 
products. Section II.J. includes a list of chemicals that consumer 
products cannot contain. Section II.K. includes a list of consumer 
products that cannot contain trichloroethylene in a combined amount 
greater than 0.01 percent by weight. Table 1 in Part A includes the VOC 
content limits for consumer products manufactured on or after May 1, 
2020.
    Section III of part A contains container labeling requirements, 
including a requirement for clear display of dates that products were 
manufactured or date codes representing the date of manufacture on 
containers or packages; special purpose spray adhesive classification 
requirements; and dilution ratios for non-aerosol floor wax strippers. 
Sections III.E and F. include label display requirements for energized 
electrical cleaner and zinc rich primers. Under section III.F aerosol 
adhesives, adhesive removers, electronic cleaners, electrical cleaners, 
energized electrical cleaners, and content products must include the 
product category, applicable VOC standard for the product as a 
percentage by weight, and the applicable substrate and/or application 
for special purpose spray adhesives on labels.
    Section IV contains reporting requirements to demonstrate 
compliance with the applicability and standards requirements in part A. 
These include maintaining records necessary to demonstrate exemptions 
under section I.B and of the para-dichlorobenzene content of solid air 
freshener, insecticide, or toilet/urinal care consumer products. 
Records must be maintained for a minimum of three years and made 
available to the Division upon request. Section IV.D. includes a list 
of information that must be reported to the Division within 90 days of 
written notice. This information includes the names and contact 
information of responsible parties, consumer product brand names for 
each product label and category, Colorado sales in pounds per year, and 
the net percent by weight of total product.
    Section V includes test methods that should be used to determine 
compliance with the requirements in part A (CARB Method 310 or through 
calculation of the VOC content from records of the amounts of 
constituents used to make the product) and whether a product is a 
liquid or solid (ASTM D4359-90(2000)e). Section VI contains a list of 
definitions used throughout part A. We propose to find that the 
provisions in part A are consistent with CAA requirements, and that 
they strengthen the SIP. We therefore propose to approve the revisions 
in part. A.
(ii) Part B
    Part B of Reg. 21 establishes new rules for limiting VOC emissions 
from architectural or industrial maintenance (AIM) coatings as of May 
1, 2020. Architectural coating, as defined in section VI.F., ``means a 
coating to be applied to stationary structures or their appurtenances 
at the site of installation, to portable buildings at the site of 
installation, to pavements, or to curbs. Architectural coating does not 
include

[[Page 67630]]

coatings applied in shop applications or to non-stationary structures 
such as airplanes, ships, boats, railcars, and automobiles, as well as 
adhesives.'' \107\ Industrial maintenance coatings, as defined in 
section VI.DD., ``means a high performance architectural coating, 
including primers, sealers, undercoaters, intermediate coats, and 
topcoats, formulated for application to substrates, including floors, 
and exposed to one or more of the following extreme environmental 
conditions: immersion in water, wastewater, or chemical solutions 
(aqueous and non-aqueous solutions), or chronic exposures of interior 
surfaces to moisture condensation; acute or chronic exposure to 
corrosive, caustic, or acidic agents, or to chemicals, chemical fumes, 
or chemical mixtures or solutions; frequent exposure to temperatures 
above 121[deg]C (250 [deg]F); frequent heavy abrasion, including 
mechanical wear and scrubbing with industrial solvents, cleansers, or 
scouring agents; or exterior exposure of metal structures and 
structural components. Industrial maintenance coatings must be labeled 
as specified in part B, section III.D.1.'' \108\
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    \107\ See p. 282 of the May 13, 2020 submittal.
    \108\ See p. 285 of the May 13, 2020 submittal.
---------------------------------------------------------------------------

    Section I contains the applicability requirements. The rules apply 
to people who sell, supply, offer for sale, distribute for sale, or 
manufacture for sale AIM coatings in the 8-hour ozone control area. 
Section I.B. includes a number of exemptions from the requirements in 
section B including AIM coatings that are manufactured in Colorado 
solely for shipment and use outside of Colorado; aerosol coating 
products, and AIM coatings that are sold in containers with a volume of 
one liter or less.
    Table 1 in section II establishes VOC content limits for 
manufacturing, blending, suppling, selling, offering for sale, and 
soliciting for application AIM coatings. Section III of part B includes 
container labeling requirements including clearly displaying dates that 
products were manufactured or date codes representing the date of 
manufacture on containers, a statement of the manufacturer's 
recommendation regarding thinning of the coating, and the VOC content 
in grams per liter of coating. Section III.D. includes a list of 
statements that should be displayed on container labels, such as ``for 
industrial use only,'' ``for blocking stains,'' ``high gloss,'' and 
``for metal substrates only.''
    Section IV contains a list of information that must be reported to 
the Division within 180 days of written notice to demonstrate 
compliance with part B requirements. This information includes the 
names and mailing address of manufacturers, the names of the coatings 
products as they appear on the labels and the application coating 
categories, the VOC content in gram per liter as determined in 
accordance with section V, and the density of the products in pounds 
per gallon.
    Section V includes test methods that should be used to determine 
compliance with the requirements in part B. Section V.A. describes the 
process for determining the VOC content of a coating. Section VI. 
contains a list of definitions used throughout part B. We propose to 
find that the provisions in part B are consistent with CAA 
requirements, and that they strengthen the SIP. We therefore propose to 
approve the revisions in part B.
b. Analysis of Reg. 7 Changes in March 22, 2021 Submittal
    The EPA proposes to approve the following changes made to Reg. 7 
with Colorado's March 22, 2021 submission.
(i) Part C, Section I
    Section I of part C contains rules for surface coating operations. 
In this submittal, the Commission expanded Section I.O wood furniture 
surface coating requirements to the surface coatings of other wood 
products such as doors, door casings, and decorative wood accents. The 
provisions apply to other wood products coating operations with 
uncontrolled actual emissions greater than or equal to 50 tpy located 
in the DMNFR Area. A detailed evaluation of section I is in the TSD for 
this action. We propose to find that the provisions in part C are 
consistent with CAA and RACT requirements, and that they strengthen the 
SIP. We therefore propose to approve the revisions in part. C.
(ii) Part E, Section II
    Section II of part E contains rules for the control of emissions 
from stationary and portable combustion equipment in the DMNFR Area. 
The revisions in art E include RACT requirements for 50 tpy major 
sources of VOC and/or NOX including a NOX 
emission limit for boilers between 50 MMBtu/hr and 100 MMBtu/hr, a 
NOX emission limit for landfill gas or biogas fired 
engines,\109\ and NOX emission limits for combustion 
turbines.
---------------------------------------------------------------------------

    \109\ The EPA will be acting on the State's RACT determination 
for landfill and biogas fired engines in a sperate action.
---------------------------------------------------------------------------

    Section II.A.4.a.(iv) expands categorical boiler RACT requirements 
for 50-100 MMBtu/hr boilers at 50 tpy major sources to comply with a 
0.1 lb/MMBtu NOX emission limit. The owners or operators of 
these boilers will continue to comply with the combustion process 
adjustment, periodic performance testing, and recordkeeping 
requirements in section II.
    Section II.A.4.b.(i)(A) was revised to reference NSPS KKKK 
NOX emission limits for the turbines constructed before 
February 18, 2005. These emission limits are included in Table 1 of 
section II.A.4.b. Section II.A.4.b.(i)(A)(1) requires that turbines 
with CEMS that are capable of operating in both combined and simple 
cycle modes show compliance with a 30-day rolling average. Section 
II.A.4.b.(iv) adds a new requirement for turbines, air pollution 
control equipment, and monitoring equipment to be operated with good 
air pollution control practices for minimizing emissions. Section 
II.A.5.c.(i)(A) includes monitoring requirements for pre and post 
February 18, 2005 turbines.
    A detailed evaluation of section II is in the TSD for this action. 
We propose to find that the provisions in section II are consistent 
with CAA and RACT requirements, and that they strengthen the SIP. We 
therefore propose to approve the revisions in part E, section II.
(iii) Part E, Section V
    Section V of part E contains new rules for the control of emissions 
from foam manufacturing in the DMNFR Area as of January 27, 2020. Foam 
manufacturing operation, as defined in section V.A.3.e., ``means any 
expanded polystyrene (EPS) production line, or portion of a production 
line, which processes raw EPS bead into final molded EPS product. 
Production line processes include, but are not limited to pre-
expansion, aging (pre-puff), and molding. The manufacturing process 
ends after the product exits the EPS mold. `Foam manufacturing 
operation' also means any production line processing methylene diphenyl 
diisocyanate (MDI), resins, and various hardeners and thickeners into 
foam products and which results in VOC emissions into the atmosphere. 
The manufacturing process ends after the product exits the drying 
tunnel.'' Section V.A.3. includes a list of definitions used in section 
V.
    Section V.A.4. establishes emission limits for foam manufacturing 
operations. Operators must limit VOC emissions from foam manufacturing 
to 3.0 lbs per 100 lbs of total material processed, averaged monthly, 
or must control VOC emissions from foam

[[Page 67631]]

manufacturing by 90%. Work practice requirements are set forth in 
section V.A.5. and require that raw materials be stored in closed, 
leak-free, labeled containers, and in a manner that minimizes 
evaporation from open containers. Sections V.A.6., 7, and 8 contain 
monitoring, recordkeeping, and reporting (MRR) requirements, including 
MRR for performance testing to determine control efficiency of emission 
control equipment, and requirements to keep records of the amounts of 
raw material processed on a daily basis, total monthly VOC emissions, 
and a manufacturer's guarantee of control equipment's emission control 
efficiencies. Records must be maintained for five years and made 
available to the Division upon request. Records of performance test 
protocols for performance tests under Section V.A.6.b. must be 
submitted to the Division for review at least thirty days before 
testing.
    A detailed evaluation of section V is in the TSD for this action. 
We propose to find that the provisions in section V are consistent with 
CAA and RACT requirements, and that they strengthen the SIP. We 
therefore propose to approve the revisions in part E, section V.
c. Analysis of Reg. 7 Changes in May 18, 2021 Submittal
    The majority of the changes to Reg. 7 from the May 18, 2021 
submittal are state-only and therefore have not been submitted for 
inclusion in the SIP. The SIP revisions from this submittal include 
editorial revisions to the outline of the regulation and numbering 
changes to part E, section I.D.4., SIP controls for existing natural 
gas fired RICE. The revisions are clerical in nature and do not affect 
the substance of the requirements. Therefore, we propose to approve the 
changes.
d. Analysis of Reg. 7 Changes in May 20, 2022 Miscellaneous Metals and 
Process Heaters Submittal
    The EPA proposes to approve the changes made to Reg. 7 with 
Colorado's May 20, 2022 miscellaneous metals and process heaters 
submittal.
(i) Part C, Section I
    Section I of part C contains rules for surface coating operations. 
The Commission has previously adopted requirements for metal surface 
coatings based on recommendations in EPA's Control of Volatile Organic 
Emissions from Existing Stationary Sources--Volume VI: Surface Coating 
of Miscellaneous Metal Parts and Products (1978), including VOC content 
limits, work practices, and recordkeeping requirements. In 2008, 
however, the EPA published a subsequent metal coating CTG, Control 
Techniques Guidelines for Miscellaneous Metal and Plastic Parts 
Coatings (Metal Coating CTG), which recommends expanding the coatings 
VOC content limits from four to fifty, including work practices, 
application methods, and recordkeeping. Therefore, in response to EPA's 
concern with Colorado's existing metal parts coating requirements as 
based on EPA's 1978 CTG, the Commission revised the metal surface 
coating requirements in part C, section I to correspond to the 
recommendations in the 2008 Metal Coating CTG.
    The revised section I.L., Manufactured Metal Parts and Metal 
Products, applies to sources where actual emissions are greater than or 
equal to 6.8 kilograms (15 lbs) per day and 1.4 kilograms (3 lbs) per 
hour. Starting January 1, 2022, section I.L requirements applied to 
metal parts and product surface coating units at facilities where total 
actual VOC emissions from all metal parts and products surface coating 
operations are greater than or equal to 2.7 tons per 12-month rolling 
period, before consideration of controls.
    Revised section I.L.1.b. removes a number of exemptions for surface 
coatings of various metal parts and products: automobiles and light-
duty trucks, metal cans, flat metal sheets and strips in the form of 
rolls or coils, large appliances, magnet wire for use in electrical 
machinery, and metal furniture. Section I.L.b.(iii) adds categories for 
which section I.L. does not apply, including certain sources regulated 
by NSPS and sources that must comply with other sections of the SIP. 
Section I.L.2.b. includes new requirements for surface coating of 
manufactured metal parts or metal products facilities and operations. 
Section I.L.2.b.(i) requires that VOC emissions from coatings and 
thinners be reduced with an emission control system having a control 
efficiency of 90% or greater. Additionally, products must comply with 
the VOC content limits established in Tables 1 and 2 of section 
I.L.2.b. A number of new definitions were added to section I.L.1.c.
    Sections I.L.3. and I.L.4. include application methods and work 
practice standards that owners and operators must use and follow. These 
include the use of high-volume low-pressure spray, roller coat, and 
airless spray; storing all VOC containing coatings, thinners, coating 
related waste materials, cleaning materials, and used shop towels in 
closed containers; and minimizing VOC emissions from cleaning of 
application, storage, mixing, and conveying equipment by cleaning 
equipment without atomizing the cleaning solvent and capturing spent 
solvent in closed containers section I.L.5. contains recordkeeping 
requirements to demonstrate compliance with section I.L. Records must 
be maintained for a minimum of five years and made available to the 
Division upon request.
    A detailed review of section I.L. is in the TSD for this action. We 
propose to find that the provisions in section I.L. are consistent with 
CAA requirements, represent RACT for the emission limits in Table 2 
``Metal Parts and Products VOC Content Limits'' and Table 7 ``Metal 
Parts and Products VOC Emission Rate Limits'' of the 2008 Miscellaneous 
Metal Parts and Products CTG, and that they strengthen the SIP. We 
therefore propose to approve the revisions in part C, section I.\110\
---------------------------------------------------------------------------

    \110\ In this action, we are not finalizing the State's 
determination that RACT for the miscellaneous metal parts CTG has 
been met, because Colorado has not adopted limits or negative 
declarations for sources listed in Table 5, Pleasure Craft Surface 
Coating VOC Content Limits or Table 6, Motor Vehicle Materials VOC 
Content Limits of the CTG for Miscellaneous Metal and Plastic Parts 
Coatings, EPA-453/R-08-003 (Sept. 2008). The State is actively 
working on adopting RACT for these sources. Therefore, we will be 
acting on these categories in a separate rulemaking.
---------------------------------------------------------------------------

(ii) Part E, Section II
    Section II of part E contains rules for the control of emissions 
from stationary and portable combustion equipment in the 8-hour ozone 
control area. The Commission revised this section of Reg. 7 to include 
provisions in the SIP that require the implementation of RACT for 
process heaters at major sources of NOX emissions. 
NOX emission limits apply to natural gas-fired and refinery 
gas-fired process heaters with a heat input rate greater than or equal 
to 5 MMBtu/hr.
    Table 2 in section II.A.4.g. contains NOX emission 
limits of 0.05 lb/MMBtu for natural gas fired and 0.1 lb/MMBtu for 
refinery fuel gas fired process heaters with a heat input rate greater 
than 5 MMBtu/hr. Section II.A.5.a. adds compliance dates for process 
heaters subject to the section II.A.4.g. requirements. Continuous 
emission monitoring in section II.A.5.b.(i), performance testing 
requirements in section II.A.5.b.(ii) were expanded to include section 
II.A.4.g. process heaters. Section II.A.6.b.(viii)(E) was added to 
include combustion process adjustment requirements for process heaters.
    A detailed evaluation of section II is in the TSD for this action. 
We propose to find that the provisions in section II

[[Page 67632]]

are consistent with CAA and RACT requirements, and that they strengthen 
the SIP. We therefore propose to approve the revisions in part E, 
section II.
e. Analysis of Reg. 7 Changes in May 20, 2022 Part D Definitions 
Submittal
    The majority of the changes to Reg. 7 from the State's May 20, 2022 
part D definitions submittal are state-only and therefore have not been 
submitted for inclusion in the SIP. The SIP revisions from this 
submittal include revisions to definitions included in Reg. 7, part D, 
section III for natural gas-actuated pneumatic controllers associated 
with oil and gas operations. The revisions to definitions associated 
with pneumatic controllers reflect more accurate and appropriate 
technical definitions and do not affect the substance of the 
requirements. Therefore, we propose to approve the changes.
f. Analysis of Reg. 7 Changes in May 14, 2018, May 13, 2020, and May 
20, 2022 Part D Oil and Gas Submittals
    In November 2021, the EPA approved the majority of revisions to 
Colorado's regulations for oil and gas operations from State 
submissions in 2018 and 2020 \111\ but deferred action on several 
portions of the submittals because we determined that Colorado's SIP 
revisions did not meet oil and gas CTG RACT requirements for testing 
and monitoring requirements for combustion control devices for storage 
vessels and centrifugal compressors. On October 20, 2021, Colorado 
submitted a letter committing to adopt and submit specific revisions by 
June 30, 2022. Specifically, the State committed to add requirements 
for performance testing of certain combustion devices consistent with 
the EPA's oil and gas CTG by using the same frequency, testing 
protocol, and recordkeeping requirements that apply to storage vessels 
and wet seal centrifugal compressors required to be controlled under 
the EPA's oil and gas CTG (i.e., storage vessels that have the 
potential for VOC emissions equal to or greater than 6 tpy). The EPA 
issued a conditional approval of Reg. 7 revisions and the State's RACT 
determination for the oil and gas CTG on May 13, 2022 \112\ based on 
the commitment letter submitted by the APCD. An evaluation of Reg. 7 
revisions from the State's May 14, 2018 and May 13, 2020 submittals and 
October 20, 2021 commitment letter is in our February 17, 2022 proposed 
rule.\113\
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    \111\ 86 FR 61071.
    \112\ 87 FR 29228.
    \113\ Proposed rule, Air Plan Conditional Approval; Colorado; 
Revisions to Regulation Number 7 and Oil and Natural Gas RACT 
Requirements for 2008 8-Hour Ozone Standard for the Denver Metro/
North Front Range Nonattainment Area, 87 FR 8997.
---------------------------------------------------------------------------

    The revisions from the May 20, 2022 part D, Oil and Gas submittal 
are consistent with the commitments in the letter \114\ and include 
provisions for performance testing or demonstration of manufacturer 
testing for combustion equipment used to control emissions from storage 
vessels in section I.E.3. and wet seal centrifugal compressors in 
section I.J.1.h. A detailed evaluation of section I is in our February 
17, 2022 proposed rule and the associated TSD for that action.\115\ We 
propose to find that the revisions in section I from the State's May 
20, 2022 part D, Oil and Gas submittal are consistent with CAA and RACT 
requirements, and that they strengthen the SIP. We also propose to find 
that the State has adopted and submitted the specific revisions it has 
committed to by June 30, 2022 and that the conditional approval will 
now convert to full approval.
---------------------------------------------------------------------------

    \114\ See https://www.coloradosos.gov/CCR/eDocketDetails.do?trackingNum=2021-00594.
    \115\ See Technical Support Document for Proposed Action on the 
Reasonably Available Control Technology Determination for Oil and 
Gas CTG Sources Within Colorado's Denver Metro/North Front Range 
Area 2008 Ozone State Implementation Plan, Air and Radiation 
Program, U.S. EPA Region 8, January 2022, available within the 
docket for this action.
---------------------------------------------------------------------------

VI. Proposed Action

    We propose to approve the majority of the OAP submittal from the 
State of Colorado for the DMNFR Area submitted on March 22, 2021. (In 
this rule we are not proposing any action on the submitted attainment 
demonstration, enhanced monitoring, or contingency measures.) 
Specifically, we propose to approve:
     Milestone and future year emissions inventories;
     RFP demonstration;
     Demonstration of RACT for oil and natural gas industry VOC 
CTG sources;
     Demonstration of RACT for certain miscellaneous metal 
parts coatings VOC CTG sources;
     Demonstration of RACT for certain VOC and NOX 
non-CTG sources;
     Demonstration of RACM implementation;
     Motor vehicle I/M program;
     NNSR program; and
     MVEBs.
    We also propose to approve SIP revisions to Reg. 21 submitted by 
the State on May 13, 2020 and to Reg. 7 submitted by the State on March 
22, 2021, May 18, 2021, and May 20, 2022 as shown in Table 7. We are 
proposing to approve Colorado's determination that the above rules 
constitute RACT for the specific categories addressed in Tables 3 and 
4. A comprehensive summary of the revisions in Colorado's Regs. 7 and 
21 organized by the EPA's proposed rule action and submittal dates are 
provided in the Table 7.

   Table 7--List of Colorado Revisions to Regs. 7 and 21 That the EPA
                           Proposes To Approve
------------------------------------------------------------------------
 Revised sections in May 14, 2018, May 13, 2020, March 22, 2021, and May
                20, 2022 submittals proposed for approval
-------------------------------------------------------------------------
May 14, 2018:
    Reg. 7, part D, section XII.J.1.
May 13, 2020, Oil and Gas Submittal:
    Reg. 7, part D, sections I.D.-D.3.a.(i), I.D.3.b.-b.(i),
     I.D.3.b.(ii), I.D.3.b.(v), I.D.3.b.(vii), I.D.3.b.(ix), I.D.4.-
     I.E.1.a., I.E.2.-.c.(ii), I.E.2.c.(iv)-c.(viii), I.F.-1.d.,
     I.F.1.g.-g.(xii), I.F.1.h.-F.2.a., I.F.2.c.-c.(vi), I.F.3.-3.a,
     I.F.3.c.-c.(i)(C), and I.J.1.-j. (renumbering).
May 13, 2020, Reg. 21 Submittal:
    Reg. 21, part A, sections I-I.A.1, I.B.-VI.AAAAAAA., part B,
     sections I.-I.A.1., I.B.-VI.TTT.
March 22, 2021 Submittal:
    Reg. 7, part C, sections I.O., I.O.2., I.O.3.a., I.O.3.b.-c.,
     I.O.4.a., I.O.5.a., part E, sections II.A.1.b., II.A.4.,
     II.A.4.a.(iii), II.A.4.a.(iv), II.A.4.b.(i)-(A)(4), II.A.4.b.(iv),
     II.A.5.c.(i)(A)-(2), II.A.6.a.(ii), II.A.6.b.(viii)(B), and III.B.
May 18, 2021 Submittal:
    Reg. 7, Outline of Regulation, parts A, B, C, and D; part E and part
     F; part E, sections I.A.3. and I.D.4.-a.(ii) (renumbering).
May 20, 2022 Misc. Metals and Process Heaters Submittal:
    Reg. 7, part C, sections I.A.6.b., I.L.1.a., I.L.1.b.(i),
     I.L.b.(ii), I.L.1.b.(iii)-(vii), I.L.1.c.(ii)-(xxvi), I.L.2.a.,
     I.L.2.b.-I.L.5.d., part D, section IIIC.4.e.(i)(D)(3)(b), part E,
     sections II.A.2.f., II.A.3.p., II.A.4., II.A.4.a.(iv),
     II.A.4.b.(iii), II.A.4.e.(ii), II.A.4.g.-(ii), II.A.5.a.-b.(iv),
     II.A.6.b.(viii)(E), and II.A.6.c.(ii).
May 20, 2022 Part D Definitions Submittal:

[[Page 67633]]

 
    Reg. 7, part D, sections III.B.2., III.B.5., III.B.7., III.B.11.,
     and III.B.13.
May 20, 2022 Part D Oil and Gas Submittal:
    Reg. 7, part D, sections I.E.3-a.(iii) and I.J.1.g.-k.
------------------------------------------------------------------------

VII. Consideration of Section 110(l) of the CAA

    Under section 110(l) of the CAA, the EPA cannot approve a SIP 
revision if the revision would interfere with any applicable 
requirement concerning attainment and reasonable further progress 
toward attainment of the NAAQS, or any other applicable requirement of 
the Act. In addition, section 110(l) requires that each revision to an 
implementation plan submitted by a state be adopted by the state after 
reasonable notice and public hearing.
    The Colorado SIP revisions that the EPA is proposing to approve do 
not interfere with any applicable requirements of the Act. The Reg. 7 
revisions submitted by the State are intended to strengthen the SIP and 
to serve as RACT for certain sources for the Colorado ozone SIP. 
Colorado's submittals provide adequate evidence that the revisions were 
adopted after reasonable public notices and hearings. Therefore, CAA 
section 110(l) requirements are satisfied.

VIII. Environmental Justice Considerations

    Executive Order 12898 \116\ 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. Additionally, Executive Order 13985 \117\ directs federal 
agencies to assess whether and to what extent their programs and 
policies perpetuate systemic barriers to opportunities and benefits for 
underserved populations, and Executive Order 14008 \118\ directs 
federal agencies to develop programs, policies, and activities to 
address the disproportionately and adverse human health, environmental, 
climate-related and other cumulative impacts on disadvantaged 
communities.
---------------------------------------------------------------------------

    \116\ Federal Actions To Address Environmental Justice in 
Minority Populations and Low-Income Populations, 59 FR 7629 (Feb. 
16, 1994).
    \117\ 86 FR 7009 (Jan. 25, 2021).
    \118\ 86 FR 7619 (Feb. 1, 2021).
---------------------------------------------------------------------------

    To identify potential environmental burdens and susceptible 
populations in the DMNFR Area, a screening analysis was conducted using 
the EJSCREEN \119\ tool to evaluate environmental and demographic 
indicators within the area, based on available data from the Census 
Bureau's American Community Survey. The tool outputs showing the 
results of this assessment are in the docket for this action. These 
results indicate that within the DMNFR Area there are census block 
groups that are above the national averages and above the 80th 
percentile (in comparison to the nation as a whole) for the numbers of 
persons experiencing low income and people of color. These populations 
may be vulnerable and subject to disproportionate impacts within the 
meaning of the executive orders described above. Further, as the 
EJSCREEN analysis is a screening-level assessment and not an in-depth 
review, it is possible that there are other vulnerable groups within 
the DMNFR Area.
---------------------------------------------------------------------------

    \119\ EJSCREEN is an environmental justice mapping and screening 
tool that provides the EPA with a nationally consistent dataset and 
approach for combining environmental and demographic indicators; 
available at https://www.epa.gov/ejscreen/what-ejscreen.
---------------------------------------------------------------------------

    As to all vulnerable groups within the DMNFR Area, as explained 
below we believe that this action will be beneficial and will tend to 
reduce impacts. When the EPA establishes a new or revised NAAQS, the 
CAA requires the EPA to designate all areas of the U.S. as either 
nonattainment, attainment, or unclassifiable. If an area is designated 
nonattainment for a NAAQS, the state must develop a plan outlining how 
the area will attain and maintain the standard by reducing air 
pollutant emissions. In this action we are proposing to approve the 
majority of the State's OAP submittal for the DMNFR Area and state 
rules as meeting RACT and satisfying other CAA requirements. 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. Approval of these rules into the SIP will establish 
federally enforceable requirements that may reduce emissions from 
operations in the area. These requirements will contribute to the 
increased protection of those residing, working, attending school, or 
otherwise present in those areas, and we propose to determine that this 
rule, if finalized, will not have disproportionately high or adverse 
human health or environmental effects on communities with environmental 
justice concerns.

IX. Incorporation by Reference

    In this document, the EPA is proposing to include regulatory text 
in an EPA final rule that includes incorporation by reference. In 
accordance with requirements of 1 CFR 51.5, the EPA is proposing to 
incorporate by reference Colorado AQCC Regulation 7 pertaining to the 
control of ozone via ozone precursors and control of hydrocarbons vial 
oil and gas emissions and Regulation 21 pertaining to Control of 
Volatile Organic Compounds from Consumer Products and Architectural and 
Industrial Maintenance Coatings discussed in section VI of this 
preamble.
    The EPA has made, and will continue to make, these materials 
generally available through www.regulations.gov and at the EPA Region 8 
Office (please contact the person identified in the FOR FURTHER 
INFORMATION CONTACT section of this preamble for more information).

X. Statutory and Executive Order Reviews

    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 approve state choices, 
provided that they meet the criteria of the CAA. Accordingly, this 
action merely proposes to approve state law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, this action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 
2011);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);

[[Page 67634]]

     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA; and
     Does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where EPA or an Indian tribe has 
demonstrated that a tribe has jurisdiction. The proposed rule does not 
have tribal implications and will not impose substantial direct costs 
on tribal governments or preempt tribal law as specified by Executive 
Order 13175 (65 FR 67249, November 9, 2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
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: October 30, 2022.
KC Becker,
Regional Administrator, Region 8.
[FR Doc. 2022-24075 Filed 11-8-22; 8:45 am]
BILLING CODE 6560-50-P