[Federal Register Volume 90, Number 150 (Thursday, August 7, 2025)]
[Proposed Rules]
[Pages 38088-38092]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-14982]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2024-0468; FRL-12884-01-R8]


Air Plan Approval; Colorado; Inspection and Maintenance Program 
Revision

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve a State Implementation Plan (SIP) revision submitted by the 
State of Colorado through the Colorado Department of Public Health and 
Environment (CDPHE) on May 16, 2022. The revision includes changes to 
the Colorado Air Quality Control Commission's Regulation Number 11, 
``Motor Vehicle Emissions Inspection Program.'' The submitted changes 
constitute a revision to Colorado's vehicle inspection and maintenance 
(I/M) SIP. Colorado's I/M SIP revision includes several minor clerical 
and typographical revisions. The I/M SIP revision also streamlines the 
visual inspection procedures used on subject vehicles in obtaining I/M 
program emissions certification compliance and vehicle registration 
renewal. CDPHE also submitted revisions to its I/M program regulations 
which were marked as ``state only'' revisions and not meant for EPA 
consideration. The EPA is not acting upon these state-only changes in 
this action.

DATES: Written comments must be received on or before September 8, 
2025.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2024-0468, 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 
https://www.regulations.gov. The EPA may publish any comment received 
to its public docket. Do not submit electronically any information you 
consider to be Confidential Business Information (CBI) or other 
information whose disclosure is restricted by statute. Multimedia 
submissions (audio, video, etc.) must be accompanied by a written 
comment. The written comment is considered the official comment and 
should include discussion of all points you wish to make. The EPA will 
generally not consider comments or comment contents located outside of 
the primary submission (i.e., on the web, cloud, or other file sharing 
system). For additional submission methods, the full EPA public comment 
policy, information about CBI or multimedia submissions, and general 
guidance on making effective comments, please visit https://www2.epa.gov/dockets/commenting-epa-dockets.
    Docket: All documents in the docket are listed in the https://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 
https://www.regulations.gov. 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: Gregory Lohrke, Air and Radiation 
Division, EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver, 
Colorado 80202-1129,

[[Page 38089]]

telephone number: (303) 312-6396, email address: 
[email protected].

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

I. Background

    The Clean Air Act (CAA) requires states with areas designated as 
Moderate, Serious, Severe, or Extreme nonattainment areas for the ozone 
national ambient air quality standard (NAAQS) to establish SIP 
provisions necessary to provide for a vehicle inspection and 
maintenance (I/M) program that will identify and repair high-emitting 
vehicles operating in the nonattainment area. See CAA sections 
182(b)(4), (c)(3), (d) and (e). The requirements for CAA-mandated I/M 
programs are codified in the federal I/M Rule at 40 CFR part 51, 
subpart S. Within the I/M Rule, 40 CFR 51.350 details the applicability 
for nonattainment areas to establish I/M programs. Certain urbanized 
Moderate ozone nonattainment areas are required to establish a 
``Basic'' I/M program. Certain urbanized Serious, Severe, and Extreme 
ozone nonattainment areas are required to implement an ``Enhanced'' I/M 
program. The performance standards \1\ for Basic and Enhanced I/M 
programs are outlined in 40 CFR 51.352 and 51.351 respectively. 
Enhanced I/M programs have additional requirements and require program 
elements intended to strengthen ozone precursor reductions over the 
Basic program. Additional I/M program features in Enhanced program 
areas include on-road testing requirements and more rigorous program 
evaluation and reporting requirements.
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    \1\ An I/M performance standard is a collection of program 
design elements which defines a benchmark program to which a state's 
proposed I/M program is compared in terms of its potential to reduce 
emissions of the ozone precursors, VOC, and NOX.
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    The Denver-Boulder-Greeley-Ft. Collins-Loveland, Colorado 
nonattainment area (Denver or the ``DMNFR area'') failed to attain the 
2008 ozone NAAQS by the applicable attainment date for Moderate 
nonattainment areas and was reclassified as a Serious nonattainment 
area, effective January 27, 2020.2 3 Since the Denver 
nonattainment area was reclassified as a Serious nonattainment area for 
the 2008 ozone NAAQS, the State of Colorado was required to establish 
an Enhanced I/M program equivalent to, or more stringent than, the 
relevant program performance standard under 40 CFR 51.351.
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    \2\ 84 FR 70897 (Dec. 26, 2019).
    \3\ The Denver area has since been reclassified as Severe for 
the 2008 ozone NAAQS. See 87 FR 60926 (Oct. 7, 2022).
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    Colorado has maintained an Enhanced I/M program for the DMNFR area 
since January 1, 1995. Colorado's Enhanced program was originally 
required under CAA section 187(a)(6) due to the Denver area's 
nonattainment designation and classification as Serious nonattainment 
for the carbon monoxide NAAQS.\4\ The State maintained the Enhanced I/M 
program between 1995 and the DMNFR area's reclassification as a Serious 
ozone nonattainment area in 2020. Since Colorado had been operating an 
I/M program meeting the Enhanced performance standard before 
reclassification as a Serious ozone nonattainment area, no additional 
program design elements were required by operation of the DMNFR area's 
reclassification to Serious for the 2008 8-hr ozone NAAQS. Colorado 
last demonstrated state program equivalency to the Enhanced program 
performance standard in its Serious ozone SIP revisions. The EPA's 
approval of this most recent demonstration of performance standard 
equivalency became effective on June 8, 2023.\5\
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    \4\ 59 FR 35875 (July 14, 1994).
    \5\ 88 FR 29827 (May 9, 2023).
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    Colorado Air Quality Control Commission's Regulation Number 11 
(Regulation No. 11) includes all provisions for the implementation of 
the State's Enhanced I/M program. Vehicles of the seven most recent 
model years are exempt from the Colorado I/M program. Discussion of 
program requirements in this and subsequent sections of this document 
apply only to non-exempt vehicles. Colorado's Enhanced I/M program 
utilizes on-board diagnostic (OBD) testing of vehicles that are eleven 
years old and newer, the dynamometer-based IM240 test for gasoline-
powered light-duty vehicles (LDV) between model year 1982 and twelve 
years old and a two-speed idle (TSI) test for all model year 1981 and 
older gasoline LDV. Colorado also operates a remote sensing program to 
fulfill the on-road testing requirement for Enhanced I/M programs under 
40 CFR 51.351. All non-diesel fueled light-duty motor vehicles 
registered in the DMNFR I/M program area are subject to these 
inspections as a prerequisite to initial or renewed registration of the 
vehicle with the State. Regulation No. 11, Part A, section I. Under 
State law, 42-4-3-10, C.R.S., a vehicle owner must provide a 
certification of emissions compliance or an emissions waiver when 
applying to renew or initially register their subject vehicle.
    On August 19, 2021, the Colorado Air Quality Control Commission 
adopted changes to Regulation No. 11. The State of Colorado submitted 
these changes to EPA as an I/M SIP revision with a cover letter dated 
May 16, 2022. The May 16, 2022, Colorado submittal is available in the 
docket for today's proposed action. Collectively, the submitted 
revisions to Regulation No. 11 revise punctuation and style, provide 
uniformity of regulatory language and internal organization of 
Regulation No. 11, and make changes to requirements for visual 
inspection of emission control equipment. The submitted revisions also 
include state-only updates to emission limits with respect to the IM240 
test to increase stringency of emission requirements for vehicles 
tested under that inspection procedure. The state-only revisions were 
excluded from the State's request to amend the federally enforceable 
SIP provisions.

II. The EPA's Evaluation

A. Regulation No. 11--Part A

    Colorado's I/M SIP revisions to Regulation No. 11, Part A make 
several minor clerical and administrative changes to subsections 
A.II.--Definitions, A.IV.--Clean Screen/Remote Emissions Sensing, and 
A.V.--Expansion of the Enhanced Emissions Program to the North Front 
Range Area. These changes include capitalization of a word in a 
definition, changes to the style of subsection markers for internal 
consistency of the regulation's notation format, and changes to the 
style and format of notation for formerly repealed sections of Part A. 
The revisions to Part A also include minor clerical and administrative 
changes in subsection A.I.--Applicability as well as the removal of 
reference in that subsection to the requirement of a visual inspection 
of emission control equipment as a first-step prerequisite for all 
emission certifications and vehicle registration renewals. The removal 
of the visual inspection as a prerequisite for all emission 
certifications will be discussed in more detail in section II.C. of 
this preamble.
    Given the nature of the submitted revisions to Regulation No. 11, 
Part A, they have no impact on emission reduction benefits provided by 
the Colorado I/M program and are consistent with CAA requirements.

B. Regulation No. 11--Part B

    Colorado's I/M SIP revisions to Regulation No. 11, Part B are 
limited to clerical and administrative changes to section XI.--Requests 
for Approval of Clean Screen Test Analyzer Systems.

[[Page 38090]]

These clerical and administrative changes include grammatical 
revisions, changes to style, and the removal of referential language, 
such as ``above'', when referring to other paragraphs and subsections 
of Regulation No. 11, Part B.
    Given the nature of the submitted revisions to Regulation No. 11, 
Part B, they have no impact on emission reduction benefits provided by 
the Colorado I/M program and are consistent with CAA requirements.

C. Regulation No. 11--Part C

    Colorado's 2022 I/M SIP revision includes amendments to Regulation 
No. 11, Part C to make several minor clerical and administrative 
changes. Minor revisions to Regulation No. 11, Part C include changes 
to sections C.II.--Exhaust Emissions Inspection Procedures, C.III.--
Emissions Control Systems Inspection Procedures, C.VIII.--Certification 
of Emissions Control, and C.XII--Clean Screen Inspection Program 
Procedures. These minor revisions include updates to subsection 
organizational notation, clerical revisions, changes to referential 
language, and updates to citations of federal regulations. Minor 
clerical changes to the organization of Regulation No. 11, Part C 
include an addition of enumerated subparagraph notations under section 
C.II.C.3. to clarify requirements for the readiness check of various 
monitors during an OBD inspection. Other minor revisions include the 
deletion of several instances of colloquial, referential language 
throughout Part C to refer to other sections and paragraphs of 
Regulation No. 11. Intra-regulation references such as ``above'', 
``below'', or ``this Paragraph'' are either deleted or deleted and 
replaced with explicit citations to the proper, referenced section of 
Regulation No. 11 to improve clarity. Colorado also updated a 
Regulation No. 11, Part C reference to 40 CFR part 86 to update the 
noted location of federal emission regulations for light-duty vehicles 
and light-duty trucks.
    The 2022 revisions to Part C also make substantive changes to 
visual inspection procedures, aftermarket catalytic converter repair 
requirements, and clarification of responsible parties for issuance of 
emissions certification in cases of vehicle engine swaps. Substantive 
changes to Regulation No. 11, Part C include the modification of the 
visual inspection procedure for inspected vehicles. Sections of Part C 
affected by the modification of the visual inspection procedures are 
sections III. and VIII. Colorado has removed the requirement for a 
visual inspection of emission control devices on all inspected vehicles 
between model years 1975 and 1995 as a first-step prerequisite to 
issuing an emissions certification. Part C, section III.A., containing 
most of the language on this requirement has been repealed. The listing 
of a successful visual inspection of emission control devices on model 
year (MY) 1975-1995 vehicles has also been repealed as a prerequisite 
for certification of emissions compliance under section VIII.A. of Part 
C. However, Colorado maintains the requirement that any waiver of the 
certification of emissions compliance will not be granted without a 
visual inspection of the vehicle's emission control devices. 
Accordingly, Colorado has included revisions to Part C, section VIII.B. 
to preserve the visual inspection as a prerequisite to the issuance of 
an emissions waiver. A discussion that approval of the removal of the 
mandatory visual inspection of particular emission control devices on 
all MY 1975-1995 vehicles would not result in interference under CAA 
section 110(l) is contained in section II.E. of this proposal.
    Colorado has also revised Regulation No. 11, Part C, section III.C. 
to modify aftermarket catalytic converter requirements. The 2022 I/M 
SIP revision requires the replacement of catalytic converters, when 
necessitated by failed vehicle inspections, shall only be made with 
original equipment manufacturer devices or California Air Resource 
Board (CARB) approved aftermarket components. This revision reflects 
Colorado's adoption of California aftermarket catalytic converter 
requirements elsewhere in the State's regulations.\6\ Colorado adopted 
California aftermarket parts requirements, effective January 1, 2021. 
CARB-approved catalytic converters have tighter criteria pollutant 
reduction requirements and higher durability requirements than federal 
standard aftermarket converters; therefore, Colorado's revisions to 
Regulation No. 11 to reflect the adoption of these California 
aftermarket catalytic converter requirements will not reduce the 
emission reduction benefits produced by the I/M program.
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    \6\ 5 Code Colo. Regs. 1001-24, Part C.
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    Colorado has also revised Regulation No. 11, Part C, section XI. to 
clarify that vehicle engine replacements will be certified as 
conforming to the applicable emission requirements by an I/M program 
certified emissions technical center licenser or their designee. This 
revision is administrative in nature and will not reduce the emission 
reduction benefits produced by the I/M program.

D. Regulation No. 11--Part D

    Colorado's 2022 I/M SIP revision includes amendments to Regulation 
No. 11, Part D to make several minor clerical and administrative 
changes. Minor revisions to Regulation No. 11, Part D include clerical 
changes to sections I. and III. to improve consistency of style of 
subsection notation and other typographic elements.
    Colorado has also revised Part D, sections I. and II. to remove 
references to visual inspection procedures which are now irrelevant 
after the State made its concurrent revisions to Part C, as discussed 
in section II.C. of this preamble. The revisions to Regulation No. 11, 
Part D are administrative and clerical in nature and will not reduce 
the emission reduction benefits produced by the I/M program.

E. CAA Section 110(l) Noninterference Evaluation

    Section 110(l) of the CAA requires that EPA not approve a revision 
to a SIP ``if the revision would interfere with any applicable 
requirement concerning attainment and reasonable further progress, or 
any other applicable requirement of [the CAA].'' In evaluating 
Colorado's submitted SIP revision, EPA considered whether approval of 
the revision would result in interference under CAA section 110(l). 
Consequently, an analysis of whether EPA's approval of the Colorado SIP 
revision would be consistent with CAA section 110(l) is presented here.
    The May 16, 2022, Colorado SIP revision submittal revised the 
elements of the State's existing vehicle inspection program necessary 
to obtain a certificate of emissions compliance or a certification of 
emissions waiver. The certificate of emissions compliance is required 
to register, or transfer ownership of a vehicle, subject to the 
Colorado I/M program's applicability thresholds, in the DMNFR I/M 
program area. A certification of emissions waiver may be issued to a 
vehicle for vehicle registration under certain conditions if it fails 
the State's exhaust emissions inspection, emissions control system 
inspection, or OBD inspection procedures.
    Under the prior, approved SIP version, between January 1, 2015, and 
the 2022 revision, light-duty vehicles were required to undergo the 
following inspections and tests:
     Exhaust Emissions Inspection: All light-duty vehicles 
model year (MY) 1982 or newer were required to undergo an IM240 test, 
or an OBD test, and obtain a pass/fail determination. Regulation No. 
11, Part C, section II.B. & II.C. (2015).

[[Page 38091]]

     Emissions Control Systems Inspection: All vehicles must be 
configured as required by 40 CFR part 86, unless specific documentation 
is provided. All MY 1975-1995 vehicles were required to undergo a 
visual inspection for the presence and operability of the air system, 
catalytic converter system, and oxygen (O2) systems. Regulation No. 11, 
Part C, section III.A. & III.B. (2015).
    If a light duty vehicle passes the exhaust emission inspection and 
there are no visible smoke emissions from the vehicle, and if an MY 
1975-1995 vehicle also passes the emission control systems inspection, 
the vehicle is issued a certification of emissions compliance. 
Regulation No. 11, Part C, section VIII.A. (2015). Vehicles that do not 
qualify for a certification of emission compliance could be issued a 
waiver if, among other qualifying conditions, the vehicle passes the 
emission control systems inspection, there are no visible smoke 
emissions from the vehicle, and the testing staff determine the vehicle 
has not been tampered with. Regulation No. 11, Part C, section VIII.B. 
(2015).
    Under the May 16, 2022, SIP revision, light-duty vehicles are 
required to undergo the following inspections and tests:
     Exhaust Emissions Inspection: All light-duty vehicles 
model year (MY) 1982 or newer are required to undergo an IM240 test, or 
an OBD test, and obtain a pass/fail determination. Regulation No. 11, 
Part C, section II.C. & II.D.
     Emissions Control Systems Inspection: All motor vehicles 
must be configured as required by 40 CFR part 86, unless specific 
documentation is provided. Vehicles subject to an OBD test for the 
Exhaust Emissions Inspection are required to undergo assessment of the 
emissions control system Malfunction Indicator Lamp (MIL) (i.e., check-
engine light) and obtain a pass/fail determination. Regulation No. 11, 
Part C, section III.A. & III.B.
    Under the effective revisions to Regulation No. 11, if a light duty 
vehicle passes the exhaust emission inspection and there are no visible 
smoke emissions from the vehicle, the vehicle may be issued a 
certification of emissions compliance. Regulation No. 11, Part C, 
section VIII.A. Vehicles that do not qualify for a certification of 
emission compliance can be issued a waiver if there are no visible 
smoke emissions from the vehicle and the testing staff determine the 
vehicle has not been tampered with. The tampering determination must be 
based on an evaluation, including a visual emissions control system 
inspection, for MY1975 and newer cars. Regulation No. 11, Part C, 
section VIII.B. (2015).
    In short, the primary change made by the May 2022 SIP submission is 
that MY 1975 through 1995 vehicles are no longer subject to a 
preliminary, mandatory visual inspection for the presence and proper 
function of the ``air system, catalytic converter system and oxygen 
systems'' \8\ as a pre-requisite for a certification of emissions 
compliance. In substitution for the across-the-board visual inspection 
requirement of these components for all MY 1975-1995 vehicles, the 
newer emission control systems inspection procedure now requires 
vehicles first go through the previously approved exhaust emission 
inspection procedures maintained by the program. If a vehicle fails 
these exhaust emission inspection procedures, it will be required to 
receive a visual inspection for these components as an additional 
condition for receiving an emissions waiver. Alternatively, the failing 
vehicle can either be repaired and retested or will not be re-
registered.
    For 20 years, EPA has consistently interpreted CAA section 110(l) 
as prohibiting the EPA from approving a ``revision of a [SIP] if the 
revision would interfere with any applicable requirement concerning 
attainment and reasonable further progress [. . .], or any other 
applicable [CAA] requirement.'' To ``interfere'' means to hamper, 
frustrate, hinder, or impede any applicable CAA provision.\7\ 
Therefore, EPA's approval of a SIP revision would be consistent with 
section 110(l) so long as ``emissions in the air are not increased,'' 
and ``status quo air quality'' is preserved.\8\ The appropriate 
analysis under section 110(l) is not standardized and is determined on 
a case-by-case basis given the nature of the SIP revision.\9\ To 
demonstrate noninterference where EPA anticipates that a SIP revision 
may result in increased emissions, a state may either substitute 
equivalent or greater emission reductions in order to preserve status 
quo air quality or submit an air quality analysis showing that the SIP 
revision will not interfere with any applicable requirements.\10\
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    \7\ Bryan A. Garner, Garner's Dictionary of Legal Usage 570 (3d 
ed. 2011); see also Merriam-Webster's Collegiate Dictionary 652 
(11th ed. 2005) (``to interpose in a way that hinders or impedes'').
    \8\ Ky. Res. Council, Inc. v. EPA, 467 F.3d 986, 991 (6th Cir. 
2006); see also Indiana v. EPA, 796 F.3d 803, 806 (7th Cir. 2015); 
Ala. Env't Council v. EPA, 711 F.3d 1277, 1292-93 (11th Cir. 2013); 
Galveston-Houston Ass'n for Smog Prevention v. EPA, 289 F. App'x 
745, 754 (5th Cir. 2008).
    \9\ Center for Biological Diversity v. EPA, 75 F.4th 174, 181 
(3rd Cir. 2023).
    \10\ See Ky. Res. Council, Inc. v. EPA, 467 F.3d at 995.
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    Accordingly, EPA must evaluate whether the revised program's 
procedures provide a reasonable substitute for the mandatory visual 
inspection procedures of all MY 1975-1995 light-duty vehicles, as 
required in Regulation No. 11 previous to the 2022 SIP revision. 
Therefore, the EPA evaluated whether the program's exhaust emission 
inspection procedures provide suitable safeguards to compensate for the 
removal of across-the-board visual inspections for the presence and 
function of these emission control components.
    The emission inspection procedures maintained by the Colorado I/M 
program are designed in accordance with EPA requirements in 40 CFR part 
51, subpart S and are SIP-approved. Principally, the EPA requirements 
for tailpipe emission inspection procedures are designed to ensure 
state I/M programs can reliably identify high-emitting vehicles due to, 
among other things, malfunctioning or inoperative emission control 
components such as catalytic converters and oxygen systems. The visual 
inspection of the particular emission control components in question is 
not one of the test elements included in the Enhanced I/M performance 
standard outlined in 40 CFR 51.351(i) for areas designated and 
classified under the 8-hour ozone standard. The air, catalytic 
converter and oxygen systems are more critical to reducing emissions of 
ozone precursors than the components listed in the component inspection 
element of the Enhanced I/M performance standard. We therefore maintain 
that the revised, streamlined emission control component inspection 
compares favorably to the emission control component inspection element 
of the Enhanced performance standard. Also, given the subjective nature 
of visual inspections, Colorado's proposed approach would not decrease 
the benefits or effectiveness of Colorado's I/M program. Therefore, it 
is reasonable to determine that it is equally, or more, effective to 
test tailpipe emissions of all MY 1975-1995 light-duty vehicles to 
identify vehicles for which these components were malfunctioning, 
absent, or inoperative as it is to visually inspect for the same 
problems.
    The Colorado revisions evaluated in this proposal streamline the 
program's overall visual emission control inspection procedures by 
limiting visual inspections to vehicles which have

[[Page 38092]]

already failed a tailpipe emissions test or OBD test. Colorado's 
tailpipe emissions tests and OBD testing are EPA-approved inspection 
procedures and are capable of making a positive discovery of a vehicle 
with malfunctioning or tampered emission control devices. Further, 
tailpipe emissions and OBD tests may eliminate visual inspection error 
and errors in inspector decision-making. Therefore, removal of the 
visual inspection procedure as a first-pass inspection feature is 
unlikely to negatively affect program performance. Additionally, this 
regulatory streamlining does not outright remove the visual inspection 
requirement and vehicles with visually detectable tampering will still 
fail to receive the State's inspection certification or a waiver of 
that certification. As stated above, there is no reasonable basis to 
assess that the revisions to Regulation No. 11 Part C discussed here 
will reduce the emission reduction benefits produced by the I/M 
program. Without cause to believe the revisions will measurably reduce 
the I/M program's emission reduction benefits, the EPA concludes that 
status-quo air quality will be preserved under the substitute program 
visual inspection procedure. Therefore, EPA's proposed approval of 
these SIP revisions would not result in interference with attainment, 
reasonable further progress, or any other applicable CAA requirement 
and approval would be consistent with CAA section 110(l).

III. Proposed Action

    The EPA is proposing to approve changes to the Colorado SIP-
approved I/M program regulation as provided in the State's May 16, 2022 
submittal. These SIP revisions include changes to Colorado Code of 
Regulations (CCR) number: 5 CCR 1001-13 Regulation No. 11, Part A, 
sections I.--Applicability, II.--Definitions, IV.--Clean Screen/Remote 
Emissions Sensing, and V.--Expansion of the Enhanced Emissions Program 
to the North Front Range Area; Part B, section XI.--Requests for 
Approval of the Clean Screen Test Analyzer Systems; Part C, sections 
II.--Exhaust Emissions Inspection Procedures, III.--Emissions Control 
Systems Inspection Procedures, VIII.--Certification of Emissions 
Control, XI.--Engine Changes, and XII.--Clean Screen Inspection Program 
Procedures; and Part D, sections I.--Licensing of Emissions Inspection 
and Readjustment Stations, Inspection-only Stations, Inspection-only 
Facilities, Enhanced Inspection Centers, Fleet Inspection Stations and 
Motor Vehicle Dealer Test Facilities, II.--Qualification of Emissions 
Mechanics and Emissions Inspectors, and III.--Registration of Emissions 
Related Repair Facilities. The EPA has made the preliminary 
determination that the submitted changes to SIP-approved regulations 
are consistent with CAA requirements; therefore, the EPA is proposing 
to incorporate these changes into the Colorado SIP.
    The EPA is not proposing action on changes to Regulation No. 11, 
Part F. These changes, although submitted in the same package as the 
revisions EPA is proposing for approval in this action, were clearly 
marked as ``state only'' revisions. The purpose of these state-only 
revisions was to increase the stringency of tailpipe emission 
thresholds for vehicle certification. As state-only revisions, the EPA 
will not evaluate the consistency of the revisions with respect to the 
relevant CAA and Federal regulation requirements.

IV. 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 the Colorado Air Quality Control Commission 
Regulation Number 11 rules, 5 CCR 1001-13--Part A, sections I., II., 
IV. and V., Part B, section XI., Part C, sections II., III., VIII., 
XI., and XII., and Part D, sections I., II., and III.--as set forth 
above. The EPA has made, and will continue to make, these materials 
generally available through https://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).

V. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the CAA and applicable 
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, EPA's role is to approve state choices, 
provided that they meet the criteria of the CAA. Accordingly, this 
action merely approves 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);
     Is not subject to Executive Order 14192 (90 FR 9065, 
February 6, 2025) because SIP actions are exempt from review under 
Executive Order 12866;
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because it approves a state program;
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001); and
     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.
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where EPA or an Indian Tribe has 
demonstrated that a Tribe has jurisdiction. In those areas of Indian 
country, the rule does not have Tribal implications and will not impose 
substantial direct costs on Tribal governments or preempt Tribal law as 
specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
Incorporation by reference, Intergovernmental relations, Nitrogen 
oxides, Ozone, Reporting and recordkeeping requirements, Volatile 
organic compounds.

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

    Dated: July 24, 2025.
Cyrus M. Western,
Regional Administrator, Region 8.
[FR Doc. 2025-14982 Filed 8-6-25; 8:45 am]
BILLING CODE 6560-50-P