Petition for Writ of Certiorari — Chamber of Commerce, et al., Petitioners v. Environmental Protection Agency, et al.

No. ____

IN THE

Supreme Court of the United States

________________________________

CHAMBER OF COMMERCE OF THE UNITED STATES

OF AMERICA, ET AL.

Petitioners,

v.

UNITED STATES ENVIRONMENTAL PROTECTION

AGENCY; LEE ZELDIN, ADMINISTRATOR, ET AL.

Respondents.

________________________________

ON PETITION FOR WRIT OF CERTIORARI TO THE UNITED

STATES COURT OF APPEALS FOR THE DISTRICT OF

COLUMBIA CIRCUIT

________________________________

APPENDIX VOLUME II OF II

________________________________

LUCINDA MINTON

LANGWORTHY

ERICA N. PETERSON

HUNTON ANDREWS KURTH

LLP

2200 Pennsylvania Avenue,

NW, Suite 900

Washington, D.C. 20037

(202) 955-1500

ELBERT LIN

Counsel of Record

DAVID M. PARKER

HUNTON ANDREWS KURTH

LLP

951 E. Byrd St., East Tower

Richmond, VA 23219

elin@Hunton.com

(804) 788-8200

Counsel for Petitioners Chamber of Commerce of the

United States of America, American Cement Association,

American Chemistry Council, American Forest & Paper

Association, American Petroleum Institute, American

Wood Council, National Association of Manufacturers,

and National Mining Association

(Additional counsel on signature page)

TABLE OF CONTENTS

Page

VOLUME I:

APPENDIX A: Opinion of the U.S. Court of

Appeals for the District of Columbia Circuit

Denying Petitions for Review and EPA’s

Motion for Vacatur, Commonwealth of

Kentucky v. EPA, No. 24-1050 (consolidated

with Nos. 24-1051, 24-1052, 24-1073, 241091) (D.C. Cir. June 26, 2026) ............................... 1a

APPENDIX B:

U.S. Environmental

Protection Agency, Reconsideration of the

National Ambient Air Quality Standards

for Particulate Matter; Final Rule, 89 Fed.

Reg. 16,202 (Mar. 6, 2024) (excerpts) .................... 46a

VOLUME II:

APPENDIX C: Clean Air Act § 109, 42

U.S.C. § 7409 ........................................................ 466a

APPENDIX D:

EPA, Responses to

Significant Comments on the 2023

Proposed Rule for the Reconsideration of

the National Ambient Air Quality

Standards

for

Particulate

Matter

(undated), Docket No. EPA-HQ-OAR2015-0072-6025 (excerpts) ................................... 470a

i

APPENDIX E:

Declaration of Aaron

Szabo (Nov. 24, 2025) ........................................... 500a

ii

466a

APPENDIX C

Clean Air Act § 109, 42 U.S.C.

§ 7409. National primary and

ambient air quality standards

secondary

(a) Promulgation

(1) The Administrator(A) within 30 days after December 31, 1970,

shall publish proposed regulations prescribing a

national primary ambient air quality standard and a

national secondary ambient air quality standard for

each air pollutant for which air quality criteria have

been issued prior to such date; and

(B) after a reasonable time for interested

persons to submit written comments thereon (but no

later than 90 days after the initial publication of such

proposed standards) shall by regulation promulgate

such proposed national primary and secondary

ambient air quality standards with such modifications

as he deems appropriate.

(2) With respect to any air pollutant for which air

quality criteria are issued after December 31, 1970,

the Administrator shall publish, simultaneously with

the issuance of such criteria and information,

proposed national primary and secondary ambient air

quality standards for any such pollutant. The

procedure provided for in paragraph (1)(B) of this

subsection shall apply to the promulgation of such

standards.

467a

(b) Protection of public health and welfare

(1) National primary ambient air quality

standards, prescribed under subsection (a) shall be

ambient air quality standards the attainment and

maintenance of which in the judgment of the

Administrator, based on such criteria and allowing an

adequate margin of safety, are requisite to protect the

public health. Such primary standards may be revised

in the same manner as promulgated.

(2) Any national secondary ambient air quality

standard prescribed under subsection (a) shall specify

a level of air quality the attainment and maintenance

of which in the judgment of the Administrator, based

on such criteria, is requisite to protect the public

welfare from any known or anticipated adverse effects

associated with the presence of such air pollutant in

the ambient air. Such secondary standards may be

revised in the same manner as promulgated.

(c) National primary ambient

standard for nitrogen dioxide

air

quality

The Administrator shall, not later than one year

after August 7, 1977, promulgate a national primary

ambient air quality standard for NO2 concentrations

over a period of not more than 3 hours unless, based

on the criteria issued under section 7408(c) of this

title, he finds that there is no significant evidence that

such a standard for such a period is requisite to

protect public health.

468a

(d) Review and revision of criteria and

standards; independent scientific review

committee; appointment; advisory functions

(1) Not later than December 31, 1980, and at fiveyear intervals thereafter, the Administrator shall

complete a thorough review of the criteria published

under section 7408 of this title and the national

ambient air quality standards promulgated under this

section and shall make such revisions in such criteria

and standards and promulgate such new standards as

may be appropriate in accordance with section 7408 of

this title and subsection (b) of this section. The

Administrator may review and revise criteria or

promulgate new standards earlier or more frequently

than required under this paragraph.

(2)(A) The Administrator shall appoint an

independent scientific review committee composed of

seven members including at least one member of the

National Academy of Sciences, one physician, and one

person representing State air pollution control

agencies.

(B) Not later than January 1, 1980, and at fiveyear intervals thereafter, the committee referred to in

subparagraph (A) shall complete a review of the

criteria published under section 7408 of this title and

the national primary and secondary ambient air

quality standards promulgated under this section and

shall recommend to the Administrator any new

national ambient air quality standards and revisions

of existing criteria and standards as may be

469a

appropriate under section 7408 of this title and

subsection (b) of this section.

(C) Such committee shall also (i) advise the

Administrator of areas in which additional knowledge

is required to appraise the adequacy and basis of

existing, new, or revised national ambient air quality

standards, (ii) describe the research efforts necessary

to provide the required information, (iii) advise the

Administrator on the relative contribution to air

pollution concentrations of natural as well as

anthropogenic activity, and (iv) advise the

Administrator of any adverse public health, welfare,

social, economic, or energy effects which may result

from various strategies for attainment and

maintenance of such national ambient air quality

standards.

(July 14, 1955, ch. 360, title I, § 109, as added Pub. L.

91-604, § 4(a), Dec. 31, 1970, 84 Stat. 1679; amended

Pub. L. 95-95, title I, § 106, Aug. 7, 1977, 91 Stat. 691.)

[CONTENT OMITTED]

470a

APPENDIX D

Responses to Significant Comments on the

2023 Proposed Rule for the

Reconsideration of the National Ambient

Air Quality Standards for Particulate

Matter

Docket Number OAR-2015-0072

U.S. Environmental Protection Agency

471a

[CONTENT OMITTED]

X.

Response to Significant Comments on

Legal, Administrative, and Procedural

Issues and to Miscellaneous Comments

A.

Legal Comments

(1)

Comment: A number of commenters contend

that the proposal exceeds the EPA’s statutory

authority. These commenters argue that there is

nothing in section 109 of the CAA that

authorizes the Agency to reconsider a decision by

the Administrator not to revise a NAAQS in a

previous statutorily prescribed NAAQS review,

and that the EPA assumes it has some inherent

authority to do so without identifying such

authority in January 2021. These commenters

recognize that section 109(d)(1) of the CAA

allows for the review and revision of the air

quality criteria or promulgation of new

standards more frequently than every five years,

but assert that under section 109 “any such

revision should be effectuated ‘in the same

manner’ in which those standards were first

‘promulgated’” and that the proposed revision to

the primary annual PM2.5 standard is not the

result of a “thorough review of…the national

ambient air quality standards” pursuant to

section 109(d)(1) of the CAA. Some commenters

suggest that the EPA may not reopen the air

quality criteria without undertaking a

comprehensive review of the entire criteria.

472a

Furthermore, these commenters suggest that

promulgation or revision of any NAAQS is

governed by section 307(d)(1)(A), and that the

only sort of reconsideration proceeding

contemplated under section 307(d) is that

described in section 307(d)(7), subparagraph (B).

They state that subpart (B) “provides that ‘the

Administrator shall convene a proceeding for

reconsideration of the rule’ in those

circumstances where a person who seeks to

challenge a final rule on the basis of an objection

not raised during the public comment period ‘can

demonstrate to the Administrator that it was

impracticable to raise such objection within such

time or if the grounds for such objection arose

after the period for public comment (but within

the time specified for judicial review) and if such

objection is of central relevance to the outcome of

the rule.’ CAA § 307(d)(7)(B) (emphasis added).”

They further note that while several petitions for

reconsideration were filed following the 2020

final decision, the Administrator did not refer to

those

petitions

in

announcing

the

reconsideration of the PM NAAQS. The

commenters also contend that reconsideration of

the 2020 final decision to retain the PM NAAQS

must be considered in light of precedents such as

American Methyl Corp. v. EPA, 749 F.2d 826

(D.C. Cir. 1984), and New Jersey v. EPA, 517

F.3d 574, 583 (D.C. Cir. 2008), noting that the

U.S. Court of Appeals for the D.C. Circuit

observed that, “when Congress has provided a

mechanism capable of rectifying mistaken

473a

actions . . . it is not reasonable to infer authority

to reconsider agency action.” The commenters

recognize that the Agency is not considering the

2020 final decision to be “mistaken” but state

that Congress provided an express “mechanism”

by which the EPA is authorized to review and

determine whether or not to revise the NAAQS

and that is under the procedures set for

expressly under section 109(d)(1) of the CAA.

Other commenters contend that the CAA does

not give the EPA unlimited authority to address

all environmental issues generally, stating that

Congress determines the extent of that

authority, not the Agency.

A number of commenters assert that, because

they believe the reconsideration is a

discretionary action, the Administration must

justify cost. Some commenters suggest that, in

reconsidering the “appropriateness” of the 2020

final decision that revisions to the PM NAAQS

were not “appropriate,” and in concluding that

revisions to the PM NAAQS are “appropriate,”

the EPA must consider all costs that would

result from the implementation of the proposed

revisions. The commenters assert that the EPA

cannot evade consideration of costs in

determining whether or not to revise a NAAQS

by invoking an unprecedented procedure (i.e., a

reconsideration) to circumvent the requirements

of section 109(d)(1) of the CAA. The commenters

state that the EPA is obligated to engage in

reasoned decision making, which requires the

474a

Administrator to account for the full range of

costs associated with the decision to reconsider

the PM NAAQS and to depart from the 2020

final decision. The commenters suggest that the

cost of a more stringent standard is a relevant

factor that must be considered and an important

aspect of the problem that cannot be ignored,

and failure to consider the full range of costs

would render any final action arbitrary and

capricious. These commenters further contend

that the EPA does not indicate that it

understands these obligations, suggesting that

the EPA’s invocation of Whitman v. American

Trucking Associations is not valid in this context.

Furthermore, these commenters argue that the

EPA must first determine whether it should

proceed to regulate at all at this time (including

treating cost as a relevant factor in reaching

such a decision) and before addressing how to

revise the NAAQS, the EPA must confront

whether to revise, and in reaching a decision to

proceed, the EPA must take into consideration

costs, citing to Michigan v. EPA, 576 U.S. 743

(2015). These commenters also suggest that if

the EPA revises the PM NAAQS as proposed, the

Agency must consider the broader social and

economic impacts of a revised NAAQS in

determining the acceptable level of risk. In so

doing, the commenters note that, in Whitman¸

the EPA cannot consider implementation costs,

but the EPA is not prohibited from considering

other costs (i.e., “disbenefits”), specifically those

listed in section 109 of the CAA, including

475a

adverse public health, welfare, social, economic,

and energy effects. These commenters also point

to Justice Breyer’s separate opinion in Whitman

and state that, in the reconsideration, the

Administrator must embrace the range of

discretion afforded to him to ensure reasoned

decision making. These commenters further

assert that the EPA should withdraw the

reconsideration proposal because it creates

regulatory

uncertainty

and

burden

in

economically

challenging

times.

These

commenters note that this would not be the first

Administrator to consider the costs and burdens

when withdrawing a reconsideration, pointing to

the decision to withdraw the reconsideration of

the ozone NAAQS in 2011. These commenters

state that the U.S. once again faces economically

challenging times, and that the costs from any

revisions that are finalized would undermine

competitiveness of U.S. manufacturing and

businesses that support critical infrastructure

and electricity needs of the U.S., and businesses

would be driven to other countries. These

commenters also argue that the standards are

unattainable, citing the Regulatory Impact

Analysis (RIA) and analyses of the RIA, and

should be withdrawn pending development of

strategies to attain the proposed standards

because Congress could not have anticipated the

difficulties that may be associated with attaining

the standard.

On the other hand, other commenters state that

476a

the EPA’s decision on reconsideration must be

based solely on health and welfare, and there is

no room for consideration of costs. They suggest

that the decision to end the previous

reconsideration of the ozone standards was made

under different circumstances and the

justification for ending the reconsideration was

never judicially upheld. They also point to the

reconsideration petitions pending before the

Agency as supporting reconsideration of the PM

NAAQS and supporting the conclusion that more

stringent standards are warranted.

Some

commenters

question

how

the

reconsideration will impact the five-year review

cycle, as mandated by the CAA. These

commenters ask if, given the reconsideration,

the EPA should complete another PM NAAQS

review in 2025 or if the next review should be in

the 2028 timeframe.

Response: This action is squarely within EPA’s

authority under section 109 of the CAA and the

EPA has always been clear it is acting under

section 109 consistent with its statutory

mandate from Congress. Congress intended the

EPA to periodically revisit and revise, as

appropriate, the air quality criteria and the

NAAQS, and this action is consistent with both

the EPA’s implicit and explicit authority to

revisit earlier decisions on the NAAQS. It is wellestablished that agencies generally have

implicit, or inherent, authority to reconsider

477a

their prior actions and take new action in a

different direction, provided the Agency is not

precluded from doing so by the statute and has a

sufficient rationale for the new action. See, e.g.,

FCC v. Fox Television Stations, Inc., 556 U.S.

502, 515 (2009); Motor Vehicle Mfrs. Ass’n v.

State Farm Mutual Auto. Ins. Co., 463 U.S. 29,

42 (1983). Certainly nothing in the Clean Air Act

precludes the EPA from revisiting earlier

decisions on NAAQS, and the language of section

109 indicates that Congress clearly intended the

EPA to revisit, reconsider, and revise earlier

decisions as appropriate.

The EPA agrees with the commenters that the

Agency is required to engage in reasoned

decision-making in this action, but maintains

that it has done so in both the notice of proposed

rulemaking and in this final action. The EPA

disagrees with the commenters that the

requirement of reasoned decision-making for

this action imposes an additional requirement

that the Administrator consider costs of

implementation of implementing a revised

standard, and with the suggestion that the

Supreme Court’s holding in Whitman does not

apply to reviews under section 109(d), including

this reconsideration. The Supreme Court held in

Whitman v. American Trucking Ass’ns that “The

text of § 109(b), interpreted in its statutory and

historical context and with appreciation for its

importance to the CAA as a whole,

unambiguously bars cost considerations from

478a

the NAAQS-setting process….” 531 U.S. 457, 471

(2001). There is no basis for suggesting that this

holding is limited to reviews undertaken under

section 109(b) but not those undertaken under

section 109(d) since every review since 1990

(including the reviews at issue in Whitman) has

necessarily been undertaken pursuant to both

section 109(b) and 109(d) and 109(d) expressly

references 109(b). Moreover, the Supreme Court

in Whitman expressly considered and rejected

the argument raised by petitioners that the EPA

must consider “disbenefits” from adverse public

health, welfare, social, economic or energy

effects. The Court noted that Congress “not only

anticipated that compliance costs could injure

the public health, but provided for that precise

exigency.” Id. at 467. The Court went to note that

“Congress, we have held, does not alter the

fundamental details of a regulatory scheme in

vague terms or ancillary provisions – it does not,

one might say, hide elephants in mouseholes”

and that the statutory text left no room for the

argument that the EPA was supposed to

incorporate considerations of the effects of

implementation into its decision making on the

NAAQS. Id. at 468. Moreover, for the same

reasons, courts have consistently held that

attainability of the standard is also not a

relevant criterion in selecting a NAAQS. See

Lead Indus. Ass’n, Inc. v. EPA, 647 F.2d 1130,

1148 (D.C. Cir. 1980); Am. Petroleum Inst. v.

Costle, 665 F.2d 1176, 1185 (D.C. Cir. 1981);

Murray Energy Corp. v. EPA, 936 F.3d 597, 623

479a

(2019). The EPA also disagrees that the

Regulatory Impact Analysis (RIA) demonstrates

that the revised standards are unattainable or

that Congress did not anticipate the difficulties

associated with attainment of a standard based

solely on public health without consideration of

economic or technological feasibility. The RIA

examines

illustrative

emissions

control

strategies toward reaching attainment and does

not purport to make a judgment whether the

standard will be attainable by the attainment

dates established in the CAA. As the DC Circuit

noted in Lead Industries, “[t]he ‘technologyforcing’ requirements of the Act are expressly

designed to force regulated sources to develop

pollution control devices that might at the time

appear to be economically or technologically

infeasible.” 647 F.2d at 1149 (internal quotation

omitted). Past experience with the NAAQS has

demonstrated this to be true, as the City of

Houston, which unsuccessfully challenged the

1979 ozone NAAQS in API on the grounds that

it was unattainable, has since attained that

standard (see 85 FR 8411, February 14, 2020).

Likewise Congress has been well aware

throughout the history of the CAA that attaining

the NAAQS may pose severe challenges. The DC

Circuit noted in Lead Industries that in

establishing the NAAQS in the 1970 CAA the

Senate drafters considered whether to use “the

concept of technical feasibility as the basis for

ambient air quality standards” but concluded

that “the health of people is more important.”

480a

647 F.2d at 1149. However, Congress well

understood that this approach could necessitate

shutdown of existing sources of pollution, result

in significant economic impacts, and might even

prove beyond the ability of industry to meet. The

court quotes Senator Muskie as saying “I think

that we have an obligation to lay down the

standards and requirements of this bill. I think

that the industry has an obligation to try to meet

them. If, in due course, it cannot, then it should

come to Congress and share with the Congress

the representatives of the people the need to

modify the policy.” Id. at 1150. Thus, the court

finds that Congress has made a policy decision to

base the standards on public health regardless of

concerns about technical feasibility and if it

turns out there is a problem then Congress is

“the only institution with the authority to

remedy the problem.” Id. Of course it is worth

noting that in later years Congress did amend

the CAA to extend the attainment deadlines for

different NAAQS where it found it appropriate

to do so in light of the challenges of attaining the

standards. For example, the attainment

deadline for areas classified as serious

nonattainment for the PM NAAQS is ten years,

rather than five years, after designation. For all

of these reasons, although the EPA does not

agree that the standards have been shown to be

unattainable, the Administrator has acted

consistently with the requirements of the CAA in

declining to consider the analyses in the RIA or

attainability of the revised standards in revising

481a

the standards under section 109.

The EPA in this action is following the direction

of Whitman and setting the NAAQS that provide

the requisite protection for public health and

welfare, as required by the CAA section 109.

Nonetheless the EPA notes that some comments

suggest that the EPA lacks authority to set such

a NAAQS under the “major questions doctrine,”

on the theory that the revised NAAQS could

have significant economic impacts. This of course

is a perverse inversion of the holding of

Whitman, which is commonly understood to be

part of the “major questions doctrine” line of

cases and held that the EPA is required to set

NAAQS to protect public health and public

welfare without consideration of the potential

economic impact of the standards. See, e.g.,

Whitman, 531 U.S. at 471 (“The text of § 109(b)

… unambiguously bars cost considerations from

the NAAQS-setting process, and thus ends the

matter for us as well as the EPA.”); see also,

West. Virginia v. EPA, 142 S. Ct. 2587, 2609

(2022) (citing Whitman for the proposition that

“Extraordinary grants of regulatory authority

are rarely accomplished through ‘modest words,’

‘vague terms,’ or ‘subtle device[s].’”).

Similarly, some commenters argue that because

under the CAA the Administrator is charged

with periodically reviewing and making such

revisions to air quality criteria and NAAQS “as

may be appropriate” that the scope of

482a

“appropriate” in NAAQS reviews must

encompass costs, under the Supreme Court’s

decision in Michigan v. EPA, 576 U.S. 743

(2015). Such an argument is also plainly

inconsistent with the Supreme Court’s decision

in both Whitman and Michigan, 18 as well as the

D.C. Circuit’s decision in Murray Energy (see 936

F.3d 597, 621-622 (D.C. Cir. 2019)).

Some commenters further suggest that the EPA

is at least required to consider costs because this

is a reconsideration completed sooner than the

statutory 5-year deadline for periodic NAAQS

reviews. The EPA notes that section 109(b)

provides that NAAQS “may be revised in the

same manner as promulgated.” The EPA

understands this provision to authorize the

Administrator to revise the NAAQS and to

require that every NAAQS revision be subject to

the same basic requirements under section 109

(and Whitman) – the standards must be based on

the air quality criteria and must be requisite to

protect the public health for primary standards

and public welfare for secondary standards. The

NAAQS decisions made in this action conform to

In Michigan, the Court did not over-rule Whitman; it

simply noted the principles of Whitman were irrelevant to the

statutory provision at issue in Michigan, highlighting textual

differences between the statutory provision before it in Michigan

and the provisions at issue in Whitman and repeating that the

provision at issue in Whitman “does not encompass cost.”

Michigan, 576 U.S. at 755–56.

18

483a

those requirements for primary and secondary

standards, respectively. 19 It would be an absurd

result, contrary to both the statute and caselaw,

if the Administrator was required to disregard

costs of implementation in setting a NAAQS

under the 5-year schedule but was free to turn

around the following year and revise the NAAQS

to a different level based on the costs of

implementation.

Similarly, the EPA rejects the suggestion that it

is required to consider costs of implementation

in deciding whether to revise the NAAQS, or that

it is required undertake any particular analysis

to justify its decision to reconsider the NAAQS.

Some commenters point to statements made by

the President and the Administrator of OIRA

regarding the completion of interagency review

of a draft final decision on a prior reconsideration

of a NAAQS. These statements, which were not

made by the EPA, do not establish that the EPA

Administrator has discretion, much less the

obligation, to consider costs of implementation in

making any decisions regarding the NAAQS

under section 109, particularly where such

considerations are prohibited under section 109.

As just noted, section 109(b) provides that

NAAQS may be revised in the same manner as

Although section 109(b) does not specify any particular

process that must be followed, this reconsideration followed the

same notice and comment rulemaking procedures, as required by

section 307(d), as previous reviews.

19

484a

promulgated, and section 109(d) provides that

the Administrator “may review and revise

criteria or promulgate new standards earlier or

more frequently than required under this

paragraph.” Nothing in section 109 suggests that

before undertaking a review of the air quality

criteria or standards the Administrator is

required to assess the potential economic or

social impacts of a possible decision that he

might reach to revise the NAAQS based on such

a review. As noted above, the Supreme Court has

held that “Congress does not alter the

fundamental details of a regulatory scheme in

vague terms or ancillary provisions -- it does not,

one might say, hide elephants in mouseholes.”

Imposing such a requirement on the

Administrator as a precondition to reviewing the

NAAQS would fundamentally alter the nature of

the NAAQS review process away from its focus

on the health of the public. “And because

§ 109(b)(1) and the NAAQS for which it provides

are the engine that drives nearly all of Title I of

the CAA, 42 U.S.C. §§ 7401-7515, that textual

commitment must be a clear one.” Whitman, 531

US at 468. There is no such textual commitment

in section 109, and the EPA concludes there is no

such requirement on the Administrator.

Some commenters also suggest that the EPA

lacks authority to undertake this action because

Congress has specified the mechanism for the

EPA to revise NAAQS in section 109(d)(1) and

this proceeding fails to satisfy the requirements

485a

of that provision. The EPA disagrees that this

action falls outside the scope of section 109(d)(1).

As noted above, section 109(d)(1) specifically

authorizes the Administrator to “review and

revise criteria or promulgate new standards

earlier or more frequently than required under

this paragraph.” That is precisely what the

Administrator

is

doing

here.

This

reconsideration is based on the thorough review

of the air quality criteria completed in 2020, as

supplemented by the additional studies,

information, and analyses in the ISA

Supplement and 2022 PA. The EPA

acknowledges that the ISA Supplement does not

itself satisfy the EPA’s obligation to periodically

complete a thorough review of the air quality

criteria. There are a number of areas, such as

respiratory effects and reproductive and

developmental effects, where commenters have

identified new studies that the EPA judged did

not warrant reopening the air quality criteria at

this time but will warrant closer consideration in

a future review. Thus, a “thorough review” of the

air quality criteria for PM, along with any

revisions to the criteria and NAAQS that may be

appropriate, should still be completed within five

years of the most recent complete review, which

concluded in 2020. However, nothing in the last

sentence of section 109(d)(1) indicates that the

authority of the Administrator to revise air

quality criteria or NAAQS is limited to the

context of a new full review of the air quality

criteria.

486a

It is true that the first sentence of section

109(d)(1) imposes a duty on the Administrator to

“complete a thorough review of the criteria

published under section 7408 of this title and the

national ambient air quality standards

promulgated under this section and shall make

such revisions in such criteria and standards and

promulgate such new standards as may be

appropriate ….” However, a careful reading

makes plain that the last sentence of section

109(d)(1)

provides

additional

authority,

independent of the requirement to undertake a

full review of the air quality criteria and revise

the criteria and the NAAQS, as appropriate,

every five years. The first sentence of section

109(d)(1) clearly specifies that every five years

the Administrator must undertake “a thorough

review of the criteria” and then, based on that

review make such changes in the air quality

criteria and the NAAQS as may be appropriate.

By contrast, the last sentence of section 109(d)(1)

simply says “may review and revise criteria or

promulgate new standards earlier or more

frequently than required under this paragraph.”

Thus, while the first sentence of section 109(d)(1)

establishes the baseline requirement that the air

quality criteria must undergo a “thorough

review” at least every five years (which may

necessitate revisions to the NAAQS), the last

sentence authorizes the Administrator to review

and revise either the air quality criteria or the

NAAQS on a shorter schedule of the

Administrator’s choosing. The plain language of

487a

the last sentence of section 109(d)(1) authorizes

the Administrator to revise the NAAQS without

revising the air quality criteria. It also

authorizes the Administrator to revise the air

quality criteria, without undertaking a

“thorough review” of the criteria. It follows that

the action of the Administrator here, to reopen

the air quality criteria to seek CASAC advice on

certain studies he considered most useful in

informing conclusions on the health effects of PM

and revising the NAAQS based the entire air

quality criteria (including both the thorough

review completed in 2020 as well as additional

studies judged most likely to be useful), was

entirely consistent with the authority granted by

Congress in section 109(d)(1).

Moreover, as explained at length in the final

decision on the 2012 PM NAAQS (78 FR 309596), “[s]ince the 1970 amendments, the EPA has

taken the view that NAAQS decisions are to be

based on scientific studies and related

information that have been assessed as a part of

the pertinent air quality criteria.” As a

consequence, when the EPA believes new science

is sufficiently important to be material to

decision making on NAAQS, it reopens the air

quality criteria to allow the CASAC and the

public, as well as the Administrator, to fully

consider the evidence. In each review the EPA

faces the question of whether “new” studies that

become available, or are brought to EPA’s

attention, at the time of the rulemaking but were

488a

not initially presented to the CASAC should be

considered for decision making on the NAAQS,

and where the EPA has concluded these studies

should be considered for decision making, the

EPA has reopened the air quality criteria for the

review, as it has done here. Thus, the EPA finds

that its approach to reopening the air quality

criteria in this reconsideration, recognizing that

there were additional studies that should be

considered for decision making, and deciding to

bring to the CASAC a draft ISA Supplement

considering those studies most likely to be useful

in judging whether the current standards are

requisite, is entirely consistent with the CAA

and the EPA’s longstanding practice.

Finally, because the Administrator is acting

within the scope of his authority under section

109 (whether that authority is characterized as

implicit or explicit), it is irrelevant that CAA

section

307(d)(7)(B)

also

requires

the

Administrator to convene a reconsideration

proceeding under certain circumstances. Section

307(d)(7)(B) is intended to ensure that any

objections to EPA’s decisions on the NAAQS are

brought before the Agency for consideration

before being raised in judicial review. Thus,

where a commenter identifies an issue of central

relevance to the rule that was impracticable to

raise an issue in public comment (or that arose

after the public comment period but before

judicial review), this provision specifies EPA

shall convene a reconsideration proceeding to

489a

consider

the

issue.

However,

section

307(d)(7)((B)

merely

specifies

certain

circumstances

when

reconsideration

is

necessary—it does not limit the availability of

reconsideration to only those circumstances, and

it does not alter the Administrator’s authority to

revise NAAQS when acting within the scope of

his authority under section 109.

(2)

Comment: Some commenters, in their

questioning of the Agency’s statutory authority

for the reconsideration, suggest that in reaching

decisions regarding the adequacy of the NAAQS

the CAA requires consideration of science-based

criteria, not policy-based criteria. Therefore, the

commenters contend that policy initiatives, such

as environmental justice, should not be included

because the EPA does not have the authority to

include them.

Response: The EPA agrees that the NAAQS

must be based on the air quality criteria,

although any decision on the appropriate

NAAQS necessarily requires the Administrator

to exercise his judgment, including with respect

to science policy and public health policy

judgments on the strength and uncertainties of

the scientific evidence. The EPA did not seek to

rewrite or expand its authority in this

reconsideration but simply set standards

requisite to protect the public health and welfare

based on the air quality criteria. The

Administrator

expressly

considered

the

490a

available information regarding health effects

among at-risk populations in reaching the

proposed decisions that the current primary

annual PM2.5 standard is not requisite to protect

public health with an adequate margin of safety,

and should be revised. The 2019 ISA and ISA

Supplement identified children, older adults,

people

with

pre-existing

diseases

(cardiovascular disease and respiratory disease),

minority populations, and low SES populations

as at-risk populations. Consistent with the

EPA’s longstanding approach to the NAAQS,

which is supported by legislative history and

case law as discussed in section I of the

preamble, the EPA set the NAAQS to protect the

at-risk populations identified for this review,

including minority and low SES populations.

(3)

Comment: Several commenters contend that

the EPA’s reconsideration of the 2020 final

decision is a discretionary action. Commenters

assert that the EPA’s proposed decision to

reconsider the PM NAAQS is premature, and

that

the

EPA

should

withdraw

its

reconsideration and defer further action to a

future required review. Commenters also

suggest that the reconsideration is based more

on a change in administration rather than the

NAAQS process as described in the CAA, that

the proposed decision is based on politics rather

than science, and that the reconsideration

should be suspended.

491a

Some commenters note that the CAA requires

review of the NAAQS no more than five years

after its previous review, and assert that the

EPA should wait the mandatory timeframe

before embarking on a new standard. Other

commenters express concerns about proposing

revisions to the standards in the reconsideration

three years ahead of the schedule of the CAA

statutorily-mandated review, suggesting that

predictability helps state and local officials

engage in long-term planning for NAAQS

implementation and other environmental

requirements.

Response: As discussed in responding to the

earlier comment in this section, the CAA

authorizes the Administrator to revise the air

quality criteria or the NAAQS more frequently

than every five years. The Administrator

initiated the reconsideration because he

concluded that the available scientific evidence

and technical information indicated that the

current standards may not be adequate to

protect public health and welfare, which is a

sufficient

and

appropriate

basis

for

reconsidering the NAAQS. When such questions

arise, the CAA does not require the

Administrator to wait until the next statutory

review deadline before addressing them.

Moreover, the PM NAAQS was most recently

revised in 2012 and Congress clearly anticipated

that the NAAQS could – and, where appropriate

based on a review of the science and the

492a

standards, should – be revised more often than

every 10 years. To the extent that the comments

related to implementation of the NAAQS

implicate consideration of the costs of

implementation or consideration of attainability

and technological feasibility, those are not

relevant considerations in making decisions

about whether to revise the NAAQS. See, e.g.,

Whitman v. American Trucking Associations,

531 U.S. 457, 465-472, 475-76 (2001); American

Petroleum Institute v. Costle, 665 F.2d 1176,

1185 (D.C. Cir. 1981); accord Murray Energy

Corporation v. EPA, 936 F.3d 597, 623-24 (D.C.

Cir. 2019). Even assuming the concerns raised in

these

comments

were

appropriate

for

consideration in this action, there are no

implementation activities that were triggered by

the 2020 final decision to retain the PM NAAQS

that could be disrupted by revising the NAAQS

in this action.

As discussed in the preamble to the final rule,

the decision to revise the NAAQS was based on

additional scientific evidence that was not part

of the criteria considered by the prior

Administrator, and additional advice from the

CASAC and public comment taking that

additional evidence into account, as well as on

the current Administrator’s judgments about the

evidence, including an approach to the

epidemiologic evidence that is more in line with

the EPA’s approach to considering such evidence

in past PM NAAQS reviews compared with the

493a

approach in the 2020 final decision. Thus, the

EPA rejects the suggestion of some commenters

that the reconsideration is not based on science

or is not fully consistent with the requirements

of the CAA.

(4)

Comment: Other comments argue that, while

the EPA may not consider the cost of

implementing the standard, it may consider the

relative proximity of the standard to background

concentrations. These commenters assert that

the proposal fails to meet this legal standard and

revisions to the NAAQS will result in a PM2.5

standard that is at or near existing background

concentrations in the Western U.S., noting for

example, increases in wildfires, and calculation

of “background” PM2.5 on a permit application.

Some commenters acknowledge EPA’s estimates

of background as 0.5-3 g m3 but suggest that

estimate is not representative of the entire

country, with one commenter citing an estimate

of 6 g m3 of “background” PM2.5 which was

modeled as part of an application to modify a

state air pollution permit.

Response: The EPA agrees that, in the context

of considering standard levels within the range

of reasonable values supported by the air quality

criteria and judgments of the Administrator, the

EPA may consider proximity to background

concentrations as a factor in the decision on

494a

whether and how to revise the NAAQS. 20

However, the EPA disagrees that the revised

primary annual PM2.5 NAAQS will be at or near

existing background levels. The EPA presented

two estimates for background PM2.5 in the

proposed rule, one based on zero-out modeling

which produced a range of 0.5-3 g m3 and one

using speciated monitoring data from IMPROVE

sites which suggests background concentrations

are in the range of 1-3 g m3. It is important to

note that, as explained in the 2022 PA, the EPA

defines U.S. background PM for this

reconsideration as any PM formed from

emissions other than U.S. anthropogenic (i.e.,

manmade) emissions. The EPA considers

IMPROVE sites, which are generally located

away from major sources of anthropogenic PM,

to be suitable sites to examine background PM,

but also notes that its estimate for background

PM was supported by the zero-out modeling

The EPA generally understands prior court decisions

addressing consideration of background concentrations of a

pollutant in NAAQS reviews to hold that while the Agency may

not establish a NAAQS that is outside the range of reasonable

values supported by the air quality criteria and the judgments of

the Administrator because of proximity to background

concentrations, it is not precluded from considering relative

proximity to background concentrations as one factor in selecting

among standards that are within that range. See American

Trucking Ass’ns v. EPA, 283 F.3d 355, 379 (D.C. Cir. 2002);

Murray Energy v. EPA, 936 F.3d 597, 622–624 (D.C. Cir. 2019);

American Petroleum Institute v. Costle, 665 F.2d 1176, 1185 (D.C.

Cir. 1982).

20

495a

which looked at U.S. regions in addition to

IMPROVE monitoring sites. By contrast, one

commenter cites an estimate of 6 g m3 of

“background” which was modeled as part of an

application to modify a state air pollution

permit. Although neither the permit application

nor the modeling itself was submitted and thus

the EPA is unable to fully assess the validity of

the modeling for these purposes, generally

“background” in this context refers to emissions

other than from the source, and would include

anthropogenic emissions from other sources,

thus explaining the higher value. Furthermore,

as some commenters recognize, emissions

attributable to wildfires may be eligible for

exclusion from design value calculation under

the Exceptional Event Rule. Thus, the EPA finds

no reason to conclude that the revised primary

annual PM2.5 NAAQS will approach background

levels. Even assuming background levels could

be somewhat higher than 1-3 g m3 they still

wouldn’t be at or near the level of the revised

primary annual PM2.5 NAAQS, and the

Administrator set the standards based on his

assessment of what is requisite to protect public

health, consistent with the requirements of the

CAA.

(5)

Comment: A number of commenters contend

that revising the PM NAAQS will impose harm,

including economic impacts, employment

impacts, exacerbating poverty, threatening

electric grid reliability, national security risk,

496a

impacts on clean energy transition, and timing

concerns, among others.

Response: The EPA notes that several

commenters provide analyses in support of their

claims that are of questionable or no relevance

(e.g., analyzing impacts of a carbon dioxide tax of

$300/ton, or of Clean Air Act regulations other

than a PM NAAQS), and which ignore the health

and economic benefits of reduced pollution and

illness. Without conceding or agreeing with any

of these commenters’ predictions, such concerns

would not be valid considerations for this action.

As discussed in the preamble to the proposed and

final rules and in response to other comments,

the Clean Air Act, as the Supreme Court held in

Whitman,

“unambiguously

bars

cost

considerations

from

the

NAAQS-setting

process,” 531 U.S. at 471, including these various

concerns raised by commenters. 21

(6)

Comment: Some commenters suggest that it

was inappropriate to propose a range of levels for

consideration in revising the primary annual

21 The EPA notes that in Am. Petroleum Inst. v. Costle, 665

F.2d 1176 (D.C. Cir. 1981), the City of Houston claimed that the

then-recently adopted 1-hour ozone standard had been set below

natural concentrations of ozone and was unattainable. The DC

Circuit rejected the argument that “attainability” is a relevant

criterion for the NAAQS, id. at 1185, and the EPA has since

determined that air quality in the area including Houston has

attained the 1979 1-hour ozone standard. See 85 FR 8411 (Feb.

14, 2020).

497a

PM2.5 standards. These commenters suggest that

the EPA should propose a recommended specific

level in order to help define exactly what the

EPA intends and to assist the public in providing

more focused and specific comments regarding

the proposal. Some commenters state that the

range is too broad and is impossible to fully

evaluate, and therefore, the EPA should

withdraw the proposal and repropose specific

standards for meaningful comment from the

public. Some commenters also assert that

proposing a range of options would be more

appropriate in an Advanced Notice of Proposed

Rulemaking (ANPRM) rather than in a

reconsideration

request

and

that

the

reconsideration request should not be to take

comments on options for new standards.

Response: The EPA disagrees that it was

inappropriate to propose a range, and to solicit

comment on potential values above and below

the range. The EPA recognizes that the NAAQS

are of great significance to a wide variety of

stakeholders and that often there is a range of

reasonable values that could be supported by the

air quality criteria and judgments of the

Administrator. Accordingly, the EPA has in the

past, as in this reconsideration, found it helpful

to identify for public comment the range of

values under closest consideration for the final

decision, along with the rationale for identifying

that range, while also soliciting comment on a

wider range in order to benefit from stakeholder

498a

input before reaching a final decision. The

proposed range for the level of the primary

annual PM2.5 standard was 9-10 μg/m3, which is

a fairly narrow range.

Had the EPA proposed a single level rather than

proposing a range of levels, the Agency still

would have solicited comment on a range of 8-11

μg/m3 for the level of the primary annual PM2.5

standard, which would have been entirely

appropriate under the Clean Air Act and general

principles of administrative law but would have

provided even less guidance to public

commenters.

Further, the EPA disagrees that it would be

more appropriate to proceed by ANPRM instead

of reconsideration, particularly given the scope

of the record and the nature of the considerations

that

informed

the

initiation

of

the

reconsideration. As explained in responding to

other comments, considering revisions to the PM

NAAQS through this reconsideration is

consistent with the EPA’s authority under the

CAA.

(7)

Comment: Some commenters state that having

multiple significant regulatory actions proposed

simultaneously interferes with the ability for

states to provide meaningful participation and

comment to the EPA, especially with

overlapping public comment periods for

proposed actions.

499a

Response: The EPA recognizes that it has in a

number of significant regulatory actions ongoing

at various stages and appreciates the

contributions of stakeholders through public

comments to each of them. In the case of this

action, the proposed decision was announced on

January 6, 2023, and the pre-publication version

of the notice of proposed rulemaking was posted

to the EPA’s website. The notice was published

in the Federal Register on January 27, 2023, and

the public comment period was open until March

28, 2023. In addition to the written public

comment period, the EPA offered a multi-day

virtual public hearing for the public to provide

oral comments to the Agency on the proposed

rule in February 2023. The EPA considers this a

fully adequate amount of time for states and

other commenters to provide comments to the

Agency regarding the proposed decisions for the

PM NAAQS Furthermore, we note that for this

reconsideration,

the

public

also

had

opportunities to provide written comments on

the 2021 draft ISA Supplement and the 2021

draft PA, as well as to offer oral comments at the

public CASAC meetings during which these

documents were reviewed.

[CONTENT OMITTED]

500a

APPENDIX E

ORAL ARGUMENT HELD ON

DECEMBER 16, 2024

IN THE UNITED STATES COURT OF

APPEALS FOR THE

DISTRICT OF COLUMBIA CIRCUIT

COMMONWEALTH

KENTUCKY, ET AL.,

OF

Petitioners,

v.

Case No. 24-1050 and

consolidated cases

U.S. ENVIRONMENTAL

PROTECTION AGENCY,

ET AL.,

Respondents.

DECLARATION OF AARON SZABO

I, Aaron Szabo, under penalty of perjury, affirm and

declare that the following statements are true and

correct to the best of my knowledge and belief, and are

501a

based on my own personal knowledge or on

information contained in the record of the United

States Environmental Protection Agency (EPA) or

supplied to me by EPA employees under my

supervision.

1.

I am the Assistant Administrator for the

United

States

Environmental

Protection

Agency Office of Air and Radiation (OAR),

which is located at 1200 Pennsylvania Avenue,

NW, Washington D.C. 20460.

2.

Prior to joining EPA, I served as a federal civil

servant, first at the Nuclear Regulatory

Commission, where I worked on nuclear power

plant issues and regulations, and then at the

White House Office of Information and

Regulatory Affairs, where I worked on major

climate and air regulations. I continued my

502a

career civil service as the Senior Counsel at

the Council on Environmental Quality, where

my role expanded to include the National

Environmental

Policy

sustainability

issues.

Act

I

and

hold

federal

degrees

in

economics, government, and politics from the

University of Maryland, College Park, and a

law

degree

from

George

Washington

University Law School.

3.

OAR

is

the

EPA

office

with

primary

responsibility for administration of the Clean

Air Act. As the Assistant Administrator for

OAR, I serve as the principal advisor to the

Administrator on matters pertaining to air

and radiation programs and am responsible

for managing these programs, including:

policy

development

and

evaluation;

503a

development of emissions standards; policy

guidance and overview; and technical support

and evaluation of regional air and radiation

program activities.

4.

Through my role as Assistant Administrator

for OAR, I am familiar with the development

and

implementation

of

EPA

programs,

policies, and regulations under the Clean Air

Act. As part of my duties, I oversee the

development

and

regulations,

policy,

implementation

and

guidance

of

under

sections 108 and 109 of the Clean Air Act, 42

U.S.C. §§ 7408–09,

including air quality

criteria and primary and secondary National

Ambient Air Quality Standards (NAAQS) for

particulate matter (PM).

504a

5.

The purpose of this declaration is to provide

the Court with context, history, and factual

assertions

in

support

of

the

EPA’s

contemporaneously filed confession of error

and motion for vacatur.

6.

Upon review of the final rule entitled

“Reconsideration of the National Ambient Air

Quality Standards for Particulate Matter,” 89

Fed. Reg. 16202 (March 6, 2024) (“2024 Rule”),

and the associated regulatory process, the

EPA no longer seeks to defend the 2024 Rule

and has asked the Department of Justice to file

a motion confessing error and seeking vacatur

of the 2024 Rule.

7.

The EPA maintains air quality criteria for

pollutants

that

must

scientific

knowledge

reflect

the

regarding

latest

adverse

505a

impacts on public health and welfare. 42

U.S.C. § 7408(a). After issuing criteria for a

pollutant, the EPA promulgates two types of

NAAQS: primary and secondary. “Primary”

NAAQS—the type at issue in this litigation—

are set “based on such criteria” at a level that

the Administrator judges to be “requisite” to

protect the “public health.” Id. § 7409(b)(1).

“Secondary” NAAQS are set “based on such

criteria” at a level that the Administrator

judges to be “requisite” to protect the “public

welfare.” Id. § 7409(b)(2). This declaration is

primarily

focused

on

the

PM

primary

standards, since that is the subject of this

litigation.

8.

The EPA first established NAAQS for PM in

1971 (36 Fed. Reg. 8186, April 30, 1971), based

506a

on an air quality criteria document prepared

by a predecessor agency component in 1969.

The primary standards consisted of a 24-hour

standard set at 260

g/m3 and an annual

standard set at 75 g/m3.

9.

In October 1979, the EPA announced the first

periodic review of the air quality criteria and

NAAQS for PM by publishing its “decision to

revise the criteria documents for particular

matter … underlying the [PM NAAQS]” and to

propose and promulgate revisions to the

NAAQS as appropriate based on the revised

criteria (44 Fed. Reg. 56730, October 2, 1979).

The Agency noted that any “[s]uch revision

necessarily entails the thorough additional

review of criteria as contemplated in Section

109(d)(1) of the Clean Air Act,” and that “[i]f

507a

any revised standards are to be proposed, they

would

be

based

on,

and

announced

concurrently with, the final revised criteria

document” (id. at 56731).

10. In July 1987, the EPA promulgated revised

PM NAAQS after multiple rounds of public

comment on the revised criteria document

and, subsequently, on the proposed rule (52

Fed. Reg. 24634, July 1, 1987). The Agency

detailed “[t]he process by which” it had

“reviewed the original criteria and standards

for particulate matter under section 109(d)”

and explained how that process culminated in

the final revisions (id. at 24635-37). Based on

a review of the revised criteria, the final rule

lowered the 24-hour primary standard to 150

508a

g/m3 and the annual primary standard to 50

g/m3.

11. In April 1994, the EPA announced its plans for

the second periodic review of the air quality

criteria and NAAQS for PM, and in 1997

promulgated revisions to the NAAQS (62 Fed.

Reg. 38652, July 18, 1997). The Agency

explained that it began the review “by

announcing its intention to develop a revised

Air Quality Criteria Document for [PM]” (id. at

38654) and that it had “announced its

proposed decision to revise the NAAQS for

PM” two years later “based on the air quality

criteria for PM” (id.). In finalizing the revised

NAAQS, the EPA rejected arguments that it

should base the standards on studies released

after

the

criteria

update

or

delay

the

509a

rulemaking to account for such studies. Citing

“section 109(d) of the Act,” the EPA explained

that it had not relied on such studies “based on

its longstanding practice of basing NAAQS

decisions on studies and related information

included in the pertinent air quality criteria

and available for CASAC review” (id. at

38662),

and

“longstanding

specifically

noted

interpretation

this

was

strengthened by new legislative enactments

enacted in 1977” as part of the addition of

section 109(d) (id. at 38662 n.15).

12. The 1997 final rule addressed the fine (PM2.5)

and coarse (PM10) fractions of PM separately

for the first time. For PM2.5, the primary

standards were lowered to an annual standard

of 15.0

g/m3 and a 24-hour standard of 65

510a

g/m3. To continue to address the health

effects of the coarse fraction of PM, the EPA

retained the existing primary annual PM10

standard and revised the form of the primary

24-hour PM10 standard to be based on the 99th

percentile of 24-hour PM10 concentrations at

each monitor in an area.

13. In May 1999, the U.S. Court of Appeals for the

District of Columbia Circuit (D.C. Circuit)

upheld the EPA’s decision to establish distinct

PM2.5 standards and to regulate coarse

particle pollution separately, but vacated the

particular 1997 PM10 standards selected by

the Agency. Am. Trucking Ass’ns, Inc. v. EPA,

175 F.3d 1027 (D.C. Cir. 1999). Pursuant to

the

D.C.

Circuit’s

decision,

the

EPA

subsequently removed the vacated 1997 PM10

511a

standards, and the pre-existing 1987 PM10

standards remained in place (65 Fed. Reg.

80776, December 22, 2000).

14. In October 1997, the EPA published its plans

for the third periodic review of the air quality

criteria and NAAQS for PM (62 Fed. Reg.

55201,

October

23,

1997).

The

Agency

explained that “[a]s with all NAAQS reviews,

the purpose is to update the criteria and to

determine whether it is appropriate to revise

the standards in light of new scientific and

technical

information”

(id.).

The

EPA

anticipated developing a revised criteria

document, providing for extensive peer review

and public comment, and proposing any

appropriate

revisions

when

the

document was finalized (id. at 55202).

criteria

512a

15. In October 2006, the EPA promulgated

revisions to the primary NAAQS for PM based

on a review of the revised criteria and after

extensive public input (71 Fed. Reg. 61144,

October

17,

2006).

The

Agency

again

reaffirmed its “view that NAAQS decisions are

to be based on scientific studies and related

information that have been assessed as a part

of the pertinent air quality criteria” (id. at

61148). The EPA lowered the 24-hour PM2.5

primary standard to 35 g/m3 and retained the

existing annual PM2.5 primary standard of

15.0

g/m3. With respect to PM10, the EPA

retained the 24-hour standard of 150

g/m3

and revoked the annual standards.

16. In February 2009, the D.C. Circuit remanded

the primary annual PM2.5 standard

for

513a

additional explanation on health protection.

Am. Farm Bureau Fed’n v. EPA, 559 F.3d 512

(D.C. Cir. 2009). The EPA responded to the

remand in its next review of the PM NAAQS,

which was initiated in 2007.

17. In June 2007, the EPA initiated the fourth

periodic review of the air quality criteria and

NAAQS for PM by issuing a call for

information (72 Fed. Reg. 35462, June 28,

2007). The Agency again explained that

“Section 109(d) requires periodic review and, if

appropriate, revision of existing air quality

criteria,” and that “EPA is then to revise the

NAAQS, if appropriate, based on the revised

air quality criteria” (id.).

18. In January 2013, the EPA promulgated

revisions to the primary NAAQS for PM based

514a

on its review of the updated air quality criteria

(78 Fed. Reg. 3086, January 15, 2013). The

Agency again reaffirmed its “longstanding

interpretation” that “NAAQS decisions are to

be based on scientific studies and related

information that have been assessed as part of

the pertinent air quality criteria,” which was

“strengthened by new legislative requirements

enacted in 1977” (id. at 3095). The EPA revised

the annual PM2.5 standardto 12.0

g/m3 and

retained the 24-hour PM2.5 standard of 35

g/m3. For the primary PM10 standard, the

EPA

retained

the

24-hour

standard

to

continue to provide protection against effects

associated

with

short-term

exposure

thoracic coarse particles (i.e., PM10-2.5).

to

515a

19. In December 2014, the EPA announced the

initiation of the fifth periodic review of the air

quality criteria and NAAQS for PM and issued

a call for information (79 Fed. Reg. 71764,

December 3, 2014). On April 14, 2020, the EPA

proposed to retain the primary PM2.5 and PM10

standards without revision based on the

results of an integrated science assessment

finalized in 2019 after peer review and public

comment, which reviewed the criteria and

scientific developments since the last review

(85 Fed. Reg. 24094, April 30, 2020).

20. In December 2020, the EPA finalized its

decision to retain the existing primary PM2.5

and PM10 standards (85 Fed. Reg. 82684,

December

18,

020).

The

Agency

again

reaffirmed its “longstanding interpretation”—

516a

“strengthened by new legislative requirements

enacted in 1977”—that “NAAQS decisions are

to be based on scientific studies and related

information that have been assessed as a part

of the pertinent air quality criteria” (id. at

82690).

21. The EPA concluded based on a review of the

criteria and the 2019 integrated science

assessment that the suite of primary PM2.5

standards were requisite to protect public

health with an adequate margin of safety and

should be retained. The EPA also judged it

appropriate to retain the primary PM10

standard to provide the requisite degree of

public health protection against exposures,

regardless of location, source of origin, or

particle composition (id. at 82725).

517a

22. In 2021, Executive Order 13990 directed

review of certain agency actions (86 Fed. Reg.

7037, January 25, 2021). An accompanying

fact sheet provided a non-exclusive list of

agency actions that agency heads should

review in accordance with that Executive

Order, including the 2020 Particulate Matter

NAAQS Decision.

23. On June 10, 2021, the Agency announced its

decision to “reconsider” the 2020 PM NAAQS

final action. The Agency announced that, in

support of the reconsideration, it would

develop a partial supplement to the 2019

integrated science assessment and a revised

policy analysis, drafts of which would be

reviewed by the CASAC. The draft supplement

was released in September 2021 (86 Fed. Reg.

518a

54186, September 30, 2021), and the final

supplement was released in May 2022 after

CASAC. For the health effects evidence, the

supplement focused on studies from the U.S.

and Canada for the health effects evidence for

which the 2019 integrated science assessment

concluded a causal relationship (i.e., short- and

long-term PM2.5 exposure and cardiovascular

effects and mortality) and studies that

addressed key scientific topics for which the

literature had evolved since the 2020 PM

NAAQS review was complete. The draft policy

assessment was released in October 2021 (86

Fed. Reg. 56263, October 8, 2021), and the

final policy assessment was released in May

2022 after CASAC review.

519a

24. In January 2023, the EPA proposed to revise

the annual PM2.5 standard and to retain the

primary 24-hour PM2.5 standard and the

primary 24-hour PM10 standard (88 Fed. Reg.

5558, January 27, 2023). In March 2024, the

EPA promulgated a final rule lowering the

primary annual PM2.5 standard from 12.0

g/m3 to 9.0

g/m3 and retaining the other

standards as proposed.

25. In support of the 2024 Rule, the EPA prepared

an illustrative analysis of the potential costs

associated with the decision to lower the

primary annual PM2.5 standard to 9.0

g/m3

titled ‘‘Regulatory Impact Analysis for the

Reconsideration of the National Ambient Air

Quality Standards for Particulate Matter”

(RIA). The EPA expressly stated in the 2024

520a

Rule that it did not rely on the RIA or consider

cost in deciding to revise the annual PM2.5

[sic] standard (89 Fed. Reg. at 16373). The RIA

used national scale emissions, controls, and

cost information to examine illustrative state

and local level attainment of the revised

annual PM2.5 standard in 2032. The estimated

costs reported in the RIA are associated with

the control devices themselves and do not

include the costs to the EPA, States, or

localities of implementing the NAAQS or the

costs of revising and implementing permit and

permit conditions beginning on the effective

date of the 2024 Rule.

26. The RIA estimated that control devices

necessitated by the 2024 Rule would cost $590

million in 2017 dollars (approximately $780

521a

million in 2025 dollars assuming an average

annual inflation rate of 3.55%) each year. This

estimate did not fully account for all the

emissions reductions needed to attain the

revised standard, and therefore was likely an

underestimate of actual cost. Furthermore,

citing technical limitations, the RIA did not

account for indirect economic impacts on the

entire economy from the illustrative control

strategy, so therefore acknowledged that there

may be additional costs to the economy that

are not captured in the estimate. Commenters

presented alternative analyses suggesting

that EPA had significantly underestimated

the costs of the rule, which, according to one

analysis, were projected to be up to $9.1

billion.” (Comments of the NAAQS Regulatory

522a

Review & Rulemaking Coalition, Attach. 3,

EPA-HQOAR-2015-0072-2361, JA2481 (Mar.

28, 2023)).

27. The EPA’s decision to revise the primary

annual PM2.5 standard triggered the Clean Air

Act’s complex implementation provisions and

related statutory deadlines for action.

28. Upon promulgation of a revised NAAQS,

States and the EPA must initiate the process

for designating areas as meeting or not

meeting the revised NAAQS, along with the

areas nearby that may be contributing to

nonattainment of the NAAQS. The timeline

for initial area designations began with

promulgation of the revised primary annual

PM2.5 standard. In accordance with CAA

section 107(d)(1), not later than 1 year after

523a

promulgation of a revised NAAQS, States

must submit to EPA their determinations

regarding whether EPA should designate

areas within the state as nonattainment,

attainment, or unclassifiable. If EPA disagrees

with a State, the Agency notifies States of

intended modifications in advance and invites

an opportunity to respond. Under CAA section

107(d)(1)(B)(i),

the

EPA

generally

must

promulgate final designations for all areas no

later than 2 years after a revised NAAQS is

promulgated, although this timeline may be

extended for up to one year if there is

“insufficient information to promulgate the

designations.” The EPA’s revision of the

primary annual PM2.5 standard in the 2024

Rule triggered an obligation to finalize area

524a

designations by a default deadline of February

7, 2026.

29. In

determining

designations,

the

EPA

evaluates each area on a case-by-case basis,

considering

the

specific

facts

and

circumstances unique to the area to support

initial

area

designations

and

associated

boundary decisions. The EPA has historically

used

area-specific

analyses

to

support

nonattainment area boundary determinations

by evaluating factors such as air quality data,

emissions

meteorology,

and

emissions-related

data,

geography/topography,

and

jurisdictional boundaries. The EPA makes

designations decisions based on complete,

quality-assured, certified air quality data in

the EPA’s Air Quality System. The EPA

525a

typically looks to monitoring data from

existing PM2.5 Federal Equivalent Methods

and Federal Reference Methods sites to

determine violations of the NAAQS. Air

agencies may flag air quality data for certain

days in the Air Quality System due to potential

impacts from exceptional events (e.g., events

such as prescribed fires on wildland, wildfires,

or high wind dust storms). Accordingly, for

purposes of initial area designations, an air

agency may submit to the EPA an exceptional

events

demonstration

with

supporting

information and analyses for each monitoring

site and day the air agency claims the EPA

should exclude from design value calculations

for designations purposes. See 40 CFR 50.1,

50.14, 51.930.

526a

30. Within 18 months of the effective date of area

designations,

any

State

in

which

a

nonattainment area is located must submit a

SIP revision that meets CAA requirements

(see 42 U.S.C. § 7513a(a)(2)). All areas initially

designated

nonattainment

for

PM2.5

are

classified as Moderate areas (see 42 U.S.C.

§ 7513(a)). The EPA previously estimated that

developing a SIP revision for PM2.5 Moderate

nonattainment

areas

costs

each

State

$585,900 per nonattainment area in 2015

dollars (or approximately $800,000 in 2025

dollars assuming an average annual inflation

rate of 3.17%). For more information, please

see the draft Information Collection Request

Supporting Statement for the PM2.5 NAAQS

State Implementation Plan Requirements

527a

Rule (EPA, DRAFT Information Collection

Request Supporting Statement for the PM2.5

National Ambient Air Quality Standards State

Implementation Plan Requirements Rule,

EPA-HQ-OAR-2013-0691-0068

(Mar.

23,

2015),

https://www.regulations.gov/document/EPAHQ-OAR-2013-0691-0068).

31. Sections 110(a)(1) and 110(a)(2) of the CAA

direct each State to develop and submit to the

EPA

a

plan

implementation,

that

provides

maintenance,

for

the

and

enforcement of the NAAQS. CAA section

110(a)(1) requires that each State make a new

SIP submission within 3 years of promulgation

of a revised primary NAAQS for approval into

the existing SIP to assure that the SIP meets

528a

the applicable requirements for such revised

NAAQS. This type of SIP submission is

commonly referred to as an “infrastructure

SIP.” The EPA’s revision of the primary

annual PM2.5 standard in the 2024 Rule

triggered States’ obligations to develop and

submit these infrastructure SIPs for approval

no later than February 7, 2027. Under CAA

section 110(k)(2), the EPA must generally

review

and

issue

a

decision

on

SIP

submissions

within

one

year

after

the

submissions are deemed complete.

32. The Clean Air Act contains preconstruction

review and permitting programs applicable to

new major stationary sources and major

modifications of existing major sources, which

is frequently called the new source review

529a

program (NSR). The new source review

program requirements vary based on whether

the construction is occuring [sic] in areas

designated attainment, nonattainment, or

unclassifiable.

In

attainment

and

unclassifiable areas, the applicable NSR

requirements

are

called

Significant

Deterioration

Prevention

of

(PSD).

In

nonattainment areas, the NSR requirements

are called nonattainment new source review

(NNSR). Until the EPA completes area

designations for the 2024 PM2.5 NAAQS, new

source review provisions applicable under an

area’s current designation for the prior PM2.5

NAAQS applies. If an area is designated

nonattainment for the 1997, 2006, or 2012

PM2.5 NAAQS, nonattainment new source

530a

review requirements will apply (see 40 CFR

51.166(i)(2) and 52.21(i)(2)). If an area is

designated as attainment or unclassifiable for

all three prior PM2.5 NAAQS, the PSD

requirements apply. Among other things, the

PSD program requires a new major stationary

source or a major modification to apply the

“best available control technology” (BACT) to

limit relevant emissions and to conduct an air

quality impact analysis to demonstrate that

the proposed major stationary source or major

modification will not cause or contribute to a

violation of any NAAQS or PSD increment (see

42 U.S.C. § 7475(a)(3) and (4); 40 CFR

51.166(j) and (k), 52.21(j) and (k)).

33. Upon the effective date of the revised primary

annual PM2.5 NAAQS in the 2024 Rule, the

531a

PSD program demonstration required under

CAA section 165(a)(3) must include the revised

NAAQS.

This

additional

requirement

increases the burden on any permit applicant

subject to these provisions beyond those that

were in effect as a consequence of the EPA’s

prior PM NAAQS revisions, most recently the

2012 PM2.5 NAAQS.

34. The EPA has previously attempted to provide

by rule that sources with pending PSD permit

applications at the time of the effective date of

the revised NAAQS need not demonstrate

compliance with the revised NAAQS to obtain

a permit, in recognition of the disruptive

effects of a mid-process change. In August

2019, however, the D.C. Circuit vacated that

provision in the PSD rules for the 2015 ozone

532a

NAAQS (see Murray Energy Corp. v. EPA, 936

F.3d 597, 627 (D.C. Cir. 2019)). Accordingly,

the 2024 Rule’s revision of the PM2.5 NAAQS

required any pending PSD permit applicants

to

revise

their

applications,

including

applications that may have been pending for

quite some time and that were in the late

stages of the approval process. This disruption

in the application process threatens further

delays, may require additional modeling and

analyses, and may result in the imposition of

additional controls and therefore previously

unexpected costs.

35. In the 2024 Rule, the EPA conceded that the

limited information added in the integrated

science assessment supplement finalized in

2022, was not itself a thorough review. The

533a

EPA

“acknowledge[d]

that

the

ISA

Supplement does not itself satisfy the EPA’s

obligation to periodically complete a thorough

review of the air quality criteria” (Response to

Comments (“RTC”) at 121, JA2800; see also 89

Fed. Reg. at 16212). The EPA further conceded

that the 2024 action did not satisfy the

requirement in CAA section 109(d)(1) to

complete a thorough review of the standards

every five years. The EPA stated that review

of the PM standards “should still be completed

within five years of the most recent complete

review, which concluded in 2020” (RTC at 121,

JA2800).

36. The process followed to revise the primary

annual PM2.5 standard in the 2024 Rule

through a partial “reconsideration” of the

534a

previous

“thorough

review”

was

unprecedented and departed markedly from

the longstanding practice utilized in finalizing

prior NAAQS revisions. The EPA purported to

“supplement” the prior review completed in

2020 with a limited and narrow review of

additional studies on some, but not all, areas

impacting NAAQS review. Following this

limited and narrow supplement, EPA flipped

its ultimate determination in 2020, reached

after a “thorough review” of the air quality

criteria

and

related

standards,

on

the

appropriate level for the primary annual PM2.5

standard. In doing so, the EPA for the first

time finalized a rule that reconsidered and

substantially revised a NAAQS outside of the

“thorough review” prescribed by statute.

535a

37. The 2024 PM NAAQS reconsideration process

did not comprise a “thorough review.” Under

CAA section 109, the EPA must first conduct a

“thorough review” of underlying air quality

criteria

and

standards

before

deciding

whether to revise a NAAQS. The combination

of a prior thorough review, and a limited

update of only some air quality criteria, cannot

meet the requirement for a “thorough review.”

If that were to be the case, EPA could serially

issue supplemental assessments, combine

them with a prior thorough review, and

continually revise standards. That cannot be

what Congress envisioned when providing

EPA with a statutory command to do a

thorough review of standards every five years.

536a

38. Prior to the 2024 Rule, the EPA consistently

took the position that, pursuant to CAA

section 109(d) and the surrounding provisions

in section 108 and 109(d), the Agency must

complete a review of and revisions to the air

quality

criteria

before

proposing

any

appropriate revisions to the NAAQS. The

Agency reaffirmed this position in 2020,

including

by

discussing

the

EPA’s

longstanding practice for considering claims

that studies released in the final stages of a

“thorough review” should be considered (85

Fed. Reg. at 82690). Citing its 1993 decision on

whether to revise the ozone NAAQS, the EPA

reiterated that “‘new’ studies may sometimes

be of such significance that it is appropriate to

delay a decision in a NAAQS review and to

537a

supplement the pertinent air quality criteria

so the studies can be taken into account” (id.

at 82961 (citing 58 Fed. Reg. 13003, 13013-14,

March 9, 1993)). Under those circumstances,

the EPA has sometimes “reopen[ed] the air

quality criteria” for supplementation before

proceeding to repropose and finalize a decision

on NAAQS revision within the same thorough

review (id.) Thus, although thorough reviews

sometimes involve multiple rounds of analysis

prior to completion, the 2024 rule was an

unusual departure from the body of practice in

which the EPA understood its decision must

reflect all the considerations under section

109(d).

39. Prior to 2024, the EPA never relied on the

second sentence of section 109(d)(1), standing

538a

alone and apart from the first sentence of

109(d)(1),

as

an

independent

source

of

authority to revise the NAAQS.

40. To date, including in the 2024 Rule, the EPA

never asserted that 109(b) alone authorized

revising the NAAQS without also referencing

109(d). To my knowledge, this issue was raised

for the first time at the oral argument for this

case before the D.C. Circuit on December 16,

2024 (see, e.g., Hr’g Tr. at 7:22-13:6).

I declare under penalty of perjury that the foregoing

is true and correct.

Executed on November 24, 2025, in Washington, D.C.

/s/ Aaron Szabo

Aaron Szabo

Assistant Administrator, Office of Air and

Radiation

U.S. Environmental Protection Agency

August 28, 2026

Respectfully submitted,

LUCINDA MINTON

LANGWORTHY

ERICA N. PETERSON

HUNTON ANDREWS

KURTH LLP

2200 Pennsylvania

Avenue, NW, Suite 900

Washington, D.C. 20037

(202) 955-1500

ELBERT LIN

Counsel of Record

DAVID M. PARKER

HUNTON ANDREWS

KURTH LLP

951 East Byrd Street,

East Tower

Richmond, VA 23219

elin@Hunton.com

(804) 788-8200

Counsel for Petitioners Chamber of Commerce of the

United States of America, American Cement

Association, American Chemistry Council, American

Forest & Paper Association, American Petroleum

Institute, American Wood Council, National

Association of Manufacturers, and National Mining

Association

MATTHEW Z. LEOPOLD

HOLLAND & KNIGHT

800 17TH STREET,

N.W.,

SUITE 1100

WASHINGTON, D.C.

20006

Counsel for Petitioners

Chamber of Commerce

of the United States of

America, American

Cement Association,

American Chemistry

Council, American

Forest & Paper

Association, American

Petroleum Institute,

American Wood

Council, National

Association of

Manufacturers, and

National Mining

Association

DARYL JOSEFFER

ANDREW R. VARCOE

STEPHANIE A.

MALONEY

U.S. CHAMBER

LITIGATION CENTER

1615 H STREET, NW

WASHINGTON, D.C.

20062

Counsel for Petitioner

Chamber of Commerce

of the United States of

America

LEAH PILCONIS

CHRISTINE MCCARTHY

AMERICAN CEMENT

ASSOCIATION

200 MASSACHUSETTS

AVE NW, SUITE 200

WASHINGTON, D.C.

20001

Counsel for Petitioner

American Cement

Association

ELLIOTT ZENICK

AMERICAN CHEMISTRY

COUNCIL

655 NEW YORK AVE.

NW

WASHINGTON DC 20001

Counsel for Petitioner

American Chemistry

Council

ERICA KLENICKI

CAROLINE T.

MCAULIFFE

NAM LEGAL CENTER

733 TENTH STREET,

NW

SUITE 700

WASHINGTON, D.C.

20001

Counsel for Petitioner

National Association of

Manufacturers

TAWNY BRIDGEFORD

NATIONAL MINING

ASSOCIATION

101 CONSTITUTION

AVE., NW, SUITE 500

EAST

WASHINGTON, D.C.

20001

Counsel for Petitioner

National Mining

Association

EMILY C. SCHILLING

SYDNEY J. SELL

HOLLAND & HART LLP

222 SOUTH MAIN

STREET, SUITE 2200

SALT LAKE CITY, UT

84101

KRISTINA (TINA) R. VAN

BOCKERN

HOLLAND & HART LLP

555 SEVENTEENTH

STREET, SUITE 3200

DENVER, CO 80202

Counsel for Petitioner

Essential Minerals

Association

BRUNN (BEAU) W.

ROYSDEN III

CULPER LAW PLLC

111 W. MARSHALL AVE.

PHOENIX, AZ 85013

Counsel for Petitioners

Warren Petersen,

President of the

Arizona State Senate,

and Steve Montenegro,

Speaker of the Arizona

House of

Representatives

VANESSA M. POMEROY

ARIZONA CHAMBER OF

COMMERCE &

INDUSTRY

100 N. 7TH AVENUE,

#120

PHOENIX, AZ 85007ௗ

Counsel for Petitioner

Arizona Chamber of

Commerce & Industry