NATURAL RESOURCES DEFENSE COUNCIL AND SIERRA CLUB,

PETITIONERS v. ENVIRONMENTAL PROTECTION AGENCY, RESPONDENT

FINE PARTICULATE LITIGATION GROUP ET AL., INTERVENORS

No. 08-1250 Consolidated with 09-1102, 11-1430

UNITED STATES COURT OF APPEALS FOR THE DISTRICT OF COLUMBIA

CIRCUIT

706 F.3d 428; 403 U.S. App. D.C. 378; 2013 U.S. App. LEXIS 214; 75 ERC (BNA)

1961; 43 ELR 20001

October 17, 2012, Argued

January 4, 2013, Decided

PRIOR HISTORY: [***1]

On Petitions for Review of Final Rules of the United

States Environmental Protection Agency.

COUNSEL: Paul Cort argued the cause for the

petitioners. Tim D. Ballo and David S. Baron entered

appearances.

Brian H. Lynk, Attorney, United States Department of

Justice, argued the cause for the respondent. Geoffrey L.

Wilcox and Stephanie L. Hogan, Attorneys, United States

Environmental Protection Agency, were on brief.

Charles H. Knauss, Shannon S. Broome, Robert T.

Smith, Denise W. Kennedy, John A. Bryson, Emily C.

Schilling, Leslie S. Ritts, Norman W. Fichthorn, Lauren

E. Freeman, Lucinda Minton Langworthy and Lorane F.

Hebert were on brief for the intervenors. Michelle M.

Schoeppe entered an appearance.

JUDGES: Before: HENDERSON and TATEL, Circuit

Judges, and WILLIAMS, Senior Circuit Judge. Opinion

for the Court filed by Circuit Judge HENDERSON.

OPINION BY: KAREN LECRAFT HENDERSON

OPINION

[*429] [**379] KAREN LECRAFT HENDERSON,

Circuit Judge: The four petitioners1 seek review of two

final rules, promulgated pursuant to the Clean Air Act

(CAA, Act), which govern implementation of the

national ambient air quality standard (NAAQS) for "fine"

particulate matter--that is, particulate matter (PM)2

having a diameter equal to or less than 2.5 micrometers

[***2] (PM2.5). See Final Clean Air Fine Particle

Implementation Rule, 72 Fed. Reg. 20,586 (Apr. 25,

2007) (PM2.5 Implementation Rule); Implementation of

the New Source Review (NSR) Program for Particulate

Matter Less Than 2.5 Micrometers (PM2.5), 73 Fed. Reg.

28,321 (May 16, 2008) (PM2.5 NSR Implementation

Rule) (collectively, Final PM2.5 Implementation Rules).3

In particular, the petitioners challenge the decision of the

Environmental Protection Agency (EPA) to promulgate

the Final PM2.5 Implementation Rules pursuant to the

general implementation provisions of Subpart 1 of Part D

of Title I of the Act, 42 U.S.C. §§ 7501-7509a (Subpart

1), rather than the particulate-matter-specific provisions

of Subpart 4 of Part D of Title I, id. §§ 7513-7513b

(Subpart 4). We agree with the petitioners that EPA erred

in applying the provisions of Subpart 1 rather than

Subpart 4.

1 They include the Natural Resources Defense

Council, Sierra Club, American Lung Association

and Medical Advocates for Healthy Air.

Page 1
2 "Particulate matter is the generic term for a

broad class of chemically and physically diverse

substances that exist as discrete particles (liquid

droplets or solids) over a wide range of sizes."

The [***3] particles "originate from a variety of

anthropogenic stationary and mobile sources as

well as from natural sources" and "may be emitted

directly or formed in the atmosphere by

transformations of gaseous emissions such as

sulfur oxides (SOx), nitrogen oxides (NOx), and

volatile organic compounds (VOC)." National

Ambient Air Quality Standards for Particulate

Matter, 62 Fed. Reg. 38,652, 38,653 (July 18,

1997).

3 Under the Act's NSR provisions, new or

modified pollutant sources must meet "strict

standards," while existing sources are

"'grandfathered.'" New York v. U.S. EPA, 413 F.3d

3, 13, 367 U.S. App. D.C. 3 (D.C. Cir. 2005).

I.

Section 109 of the Act mandates that EPA establish a

primary NAAQS for each air pollutant for which EPA

has issued "air quality criteria" under CAA section 108.

42 U.S.C. § 7409(a)(1).4 The Act defines [*430]

[**380] each such NAAQS as that standard "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." Id. § 7409(b)(1). EPA is required to

"complete a thorough review" of each pollutant's standard

and air quality criteria "at five-year intervals" and "make

such revisions [***4] in such criteria and standards and

promulgate such new standards as may be appropriate."

Id. § 7409(d)(1). Once a NAAQS has been established,

each state must adopt and submit to EPA for approval a

State Implementation Plan (SIP) that "provides for

implementation, maintenance, and enforcement of [the

NAAQS] in each air quality control region (or portion

thereof) within such State." Id. § 7410(a)(1). Each SIP

must "include enforceable emission limitations and other

control measures, means, or techniques . . . , as well as

schedules and timetables for compliance, as may be

necessary or appropriate to meet the [CAA's] applicable

requirements." Id. § 7410(a)(2)(A).

4 The Act also requires EPA to promulgate a

secondary standard, "the attainment and

maintenance of which . . . is requisite to protect

the public welfare from any known or anticipated

adverse effects associated with" the pollutant. 42

U.S.C. § 7409(b)(2). In this case, EPA

promulgated a single NAAQS as both the primary

and the secondary standard.

Part D of CAA Title I governs "Plan Requirements

for Nonattainment Areas" (that is, areas that have not

attained compliance with the applicable NAAQS) and

Subpart 1 thereof, added to the [***5] Act in 1977,

addresses "Nonattainment Areas in General." Subpart 1

provides generally that, once EPA designates an area as

"nonattainment," it "may classify the area" so as to

establish an attainment deadline and it must establish a

schedule for the state encompassing the nonattainment

area to submit a SIP. Id. § 7502(a)(1)(A). The SIP, in

turn, is required, inter alia, to (1) provide for

implementation of control measures, (2) inventory

existing emissions, (3) identify and quantify pollutant

emissions permissible under the SIP from the

construction and operation of all major new stationary

emission sources, (4) require NSR permits for such

construction and operation and (5) establish compliance

schedules and timetables. Id. § 7502(c). Pursuant to this

regime, in 1971, EPA established a particulate matter

NAAQS applicable to "Total Suspended Particles," i.e.,

particulate matter up to 25-45 micrometers in diameter.

In 1987, EPA revised the NAAQS to apply only to

particles equal to or smaller than 10 micrometers

(PM10)--a "size-specific indicator" it determined

"represent[ed] those particles small enough to penetrate

to the thoracic region" because "[t]he risks of adverse

health effects [***6] associated with deposition of

typical ambient fine and coarse particles in the thorax

(tracheobronchial and alveolar regions of the respiratory

tract) are markedly greater than those associated with

deposition in the extrathoracic (head) region." Revisions

to the National Ambient Air Quality Standards for

Particulate Matter, 52 Fed. Reg. 24,634, 24,639 (July 1,

1987) (footnote omitted) (1987 PM NAAQS Revisions).

In 1990, the Congress amended CAA Part D by

adding to it Subparts 2 through 5, each of which contains

additional provisions governing nonattainment plan

requirements for a particular pollutant or group of

pollutants. At issue here, Subpart 4 applies to "Particulate

Matter Nonattainment Areas" and covers such matters as

setting attainment dates for PM nonattainment areas,

classifying the nonattainment areas (as "moderate" or

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2013 U.S. App. LEXIS 214, ***2; 75 ERC (BNA) 1961
"serious"), reclassifying them (e.g., upon failure to attain)

and extending attainment dates. 42 U.S.C. §§

7513-7513b; see also id. §§ 7511-7511f (ozone-specific

requirements); [*431] [**381] id. §§ 7512-7512a

(carbon monoxide-specific requirements).

In 1997, EPA again revised the particulate matter

NAAQS, this time setting separate PM2.5 standards for

fine particles (having [***7] a diameter of 2.5

micrometers or less), while retaining the existing PM10

standards. National Ambient Air Quality Standards for

Particulate Matter, 62 Fed. Reg. 38,652, 38,654 nn.5-6

(July 18, 1997) (Final PM NAAQS Rule). We upheld the

new particulate matter standards in 2002 after remand

from the United States Supreme Court. See Am. Trucking

Ass'ns v. EPA, 283 F.3d 355, 350 U.S. App. D.C. 254

(D.C. Cir. 2002) (applying Whitman v. Am. Trucking

Ass'ns, 531 U.S. 457, 121 S. Ct. 903, 149 L. Ed. 2d 1

(2001)).

In 2005, EPA published its Proposed Rule To

Implement the Fine Particle National Ambient Air

Quality Standards, 70 Fed. Reg. 65,984 (Nov. 1, 2005).

EPA subsequently issued the final fine particle

implementation rule in two stages. In 2007, it published

the PM2.5 Implementation Rule, setting out the general

SIP requirements for PM2.5. EPA followed up in 2008

with the PM2.5 NSR Implementation Rule to govern the

NSR permitting process. In each of the two Final PM2.5

Implementation Rules, EPA expressly followed the

general implementation provisions in Subpart 1 of Part D

rather than Subpart 4's particulate-material-specific

provisions. See PM2.5 Implementation Rule, 72 Fed.

Reg. at 20,589 ("EPA is issuing this rule to implement

the 1997 PM2.5 [***8] NAAQS in accordance with the

statutory requirements of the CAA set forth in Subpart 1

of Part D of Title 1, i.e., sections 171-179B of the Act. . .

. EPA has concluded that Congress did not intend the

Agency to implement particulate matter NAAQS other

than those using PM10 as the indicator in accordance

with Subpart 4 of Part D of Title 1 . . . ."); PM2.5 NSR

Implementation Rule, 73 Fed. Reg. at 28,332 ("We do not

agree that subpart 4 of part D applies to PM2.5

nonattainment areas. Subpart 4 was added to the Act by

Congress specifically to address the PM10 NAAQS. We

believe that the PM2.5 standard should be implemented

under subpart 1 of part D, which is the general provision

of the Act related to NAAQS implementation."). The

petitioners filed timely petitions for review of both the

PM2.5 Implementation Rule and the PM2.5 NSR

Implementation Rule.

II.

We review EPA's interpretation of the CAA under

Chevron U.S.A. Inc. v. Natural Res. Def. Council, Inc.,

467 U.S. 837, 104 S. Ct. 2778, 81 L. Ed. 2d 694 (1984).

See Natural Res. Def. Council v. EPA, 489 F.3d 1250,

1257, 376 U.S. App. D.C. 414 (D.C. Cir. 2007). Under

Chevron:

We first ask "whether Congress has

directly spoken to the precise question at

issue," in which case we "must give effect

to [***9] the unambiguously expressed

intent of Congress." If the "statute is silent

or ambiguous with respect to the specific

issue," however, we move to the second

step and defer to the agency's

interpretation as long as it is "based on a

permissible construction of the statute."

Id. (quoting Chevron, 467 U.S. at 842-43) (other

quotation marks omitted). Before addressing whether

EPA correctly applied Subpart 1 under the Chevron

framework, we first consider the timeliness of the

petitioners' instant challenge.

A.

EPA contends the petitioners' challenge is untimely

because it should have been raised in 1997 when EPA

issued the Final PM NAAQS Rule, which, EPA

maintains, set out its final decision on Subpart [**382]

1's [*432] applicability. Because we conclude EPA did

not take final reviewable action in 1997, the petitioners'

challenge is timely.5

5 EPA acknowledges the instant petitions for

review of the PM2.5 Implementation Rule and the

PM2.5 NSR Implementation Rule were timely

filed within sixty days after each rule's publication

as required under 42 U.S.C. § 7607(b)(1). See Br.

of Resp't 1.

In urging that it finalized its decision in 1997, EPA

relies on two excerpts from the preamble to the 1997

Final PM NAAQS [***10] Rule. First, EPA cites its

response to comments challenging its authority to

promulgate a separate PM2.5 standard given that the

1990 amendments referred only to a PM10 standard. At

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2013 U.S. App. LEXIS 214, ***6; 75 ERC (BNA) 1961
the conclusion of its response, EPA offered the following

defense of its authority to promulgate the new PM2.5

standards, rooted in Subpart 1, couched in plainly

tentative language:

EPA's analysis of its ability to

implement a PM2.5 standard under the

provisions of subpart 1 of Part D of Title I

does not support the view that Congress

prohibited EPA from promulgating such a

standard. Congress clearly specified an

approach to the implementation of the

PM10 standard in the provisions of

subpart 4 of Part D of Title I of the Act.

The EPA believes that the clear and

express linkage of that approach to the

PM10 standard indicates that a different

PM standard should be implemented under

the general principles of subpart 1 of Part

D of Title I of the Act. That Congress

directed specifically how EPA and the

States should implement the PM10

standard does not carry with it the

implication that Congress intended to

prohibit EPA from exercising its otherwise

clear and express authority to adopt a PM

standard based on [***11] a different

metric . . . .

Final PM NAAQS Rule, 62 Fed. Reg. at 38,695

(emphases added). Some pages later, in a footnote, EPA

more affirmatively, albeit summarily, stated its position

that implementation of the new standard need not and

would not be governed by Subpart 4: "The SIP

requirements of subpart 4 of Part D of Title I of the Act

apply to SIPs for areas designated as not attaining

NAAQS for PM10 . Those requirements will not apply to

SIPs to implement the PM2.5 NAAQS." Id. at 38,704

n.96. We conclude these two unembellished snippets,

buried in the preamble to the 1997 Final PM NAAQS

Rule, did not constitute final agency action so as to be

reviewable in 1997.

"A final agency action is one that marks the

consummation of the agency's decisionmaking process

and that establishes rights and obligations or creates

binding legal consequences." Natural Res. Def. Council

v. EPA, 559 F.3d 561, 564, 385 U.S. App. D.C. 132 (D.C.

Cir. 2009) (citing Bennett v. Spear, 520 U.S. 154, 177-78,

117 S. Ct. 1154, 137 L. Ed. 2d 281 (1997)). We have

observed that "[w]hile preamble statements," such as

those just quoted, "may in some unique cases constitute

binding, final agency action susceptible to judicial

review, this is not the norm." Id. at 564-65 (citations

[***12] omitted). As this case is not a "unique" one, we

adhere to the norm.

The above quoted excerpts appear in a document

expressly intended to "describe[] EPA's decision to revise

the national ambient air quality standards (NAAQS) for

particulate matter (PM)," Final PM NAAQS Rule, 62

Fed. Reg. at 38,652 (emphasis added)--it did not purport

to detail how the revised standards should be

implemented. Indeed, EPA had earlier addressed the

issue of implementation in a separate Interim

Implementation Policy on New or Revised Ozone and

Particulate Matter (PM) National Ambient Air Quality

Standards (NAAQS), 61 Fed. Reg. 65,752 (Dec. 13,

1996) (Interim Implementation [*433] [**383] Policy).

Although the Interim Implementation Policy likewise

expressed an intent to apply Subpart 1 to implement the

PM2.5 standard, 61 Fed. Reg. at 65,753, it made clear

that, as its name suggests, it was only a temporary policy,

which "would represent EPA's preliminary views" and

"while it m[ight] include various statements that States

must take certain actions, these statements [we]re made

pursuant to EPA's preliminary interpretations, and thus

d[id] not bind the States and public as a matter of law."

Id. at 65,752 (emphases added). [***13] Accordingly,

"[o]nly after EPA ha[d] made its interpretations final

through rulemaking"--"follow[ing] the requirements of

the Administrative Procedure Act, 5 U.S.C. section

553(b) and (c)"--"will they be binding on the States and

public as a matter of law." Id. Given EPA's expressed

intent to issue a final, binding notice-and-comment rule

on the issue--to supplant its "preliminary" policies--we do

not see how the quoted lines from the preamble to the

1997 rule revising the standard itself "mark the

consummation of the agency's decisionmaking process"

on how to implement the standard so as to constitute final

agency action. Bennett v. Spear, 520 U.S. at 177-78

(internal quotation marks omitted). Instead, we conclude

EPA consummated the decisionmaking process to

implement the PM2.5 standard only when it published its

final views in the two Final PM2.5 Implementation Rules

now under review. Notwithstanding its express and

indefinite deferral of a final implementation policy in

1997, EPA argues the Supreme Court's decision in

Whitman v. American Trucking Associations, 531 U.S.

457, 121 S. Ct. 903, 149 L. Ed. 2d 1 (2001), requires us

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2013 U.S. App. LEXIS 214, ***10; 75 ERC (BNA) 1961
to hold otherwise. We are not so persuaded.

In Whitman, the Supreme Court reviewed EPA's

decision [***14] to implement its "8-hour" 0.08 ppm

NAAQS for ozone--which replaced the previous 1-hour

ozone standard of 0.12 ppm--under Subpart 1's general

nonattainment area provisions rather than under Subpart

2's ozone-specific provisions added in 1990. See National

Ambient Air Quality Standards for Ozone, 62 Fed. Reg.

38,856, 38,873 (July 18, 1997) (Final Ozone NAAQS

Rule) ("[T]he provisions of subpart 1 of part D of Title I

of the Act would apply to the implementation of the new

8-hour O3standards."). The Court concluded that, in the

main, the new ozone NAAQS should be implemented

pursuant to Subpart 2 notwithstanding Subpart 2 was

enacted to address the former 1-hour standard and some

provisions might therefore be "ill fitted to implementation

of the revised standard" and thus leave "gaps" for EPA to

fill under Chevron step 2. Whitman, 531 U.S. at 483-84.

The Whitman Court first addressed the threshold question

whether Subpart 1 constituted final agency action subject

to review and concluded that it did. See id. at 477-78.

Addressing the Interim Implementation Policy,

which covered both the ozone and the particulate matter

standards, the Whitman Court acknowledged: "If the EPA

had done no more, [***15] we perhaps could accept its

current claim that its action was not final." Id. at 477. The

Court explained, however, that, vis-à-vis the ozone

standard, EPA had done "more." After the White House

issued a "'Memorandum for the Administrator of the

Environmental Protection Agency' that prescribed

implementation procedures for the EPA to follow," EPA

"supplemented this memorandum with an explanation of

the implementation procedures." Id.; see Implementation

of Revised Air Quality Standards for Ozone and

Particulate Matter, 62 Fed. Reg. 38,421, 38,422 (July 18,

1997) (Memorandum of July 16, 1997); Implementation

Plan for Revised Air Quality Standards, 62 Fed. Reg.

38,423 (Implementation Memorandum Supplement).

[*434] [**384] In a section of the Implementation

Memorandum Supplement titled "Implementation of

Ozone Standard," EPA explained that, after receiving

comments on the proposed Interim Implementation

Policy, it had "reconsidered" its interpretation in part and

determined that "Subpart 2 should continue to apply as a

matter of law for the purpose of achieving attainment of

the current 1-hour standard." Id. at 38,424. But EPA

made clear it adhered to its previously expressed view

that "[o]nce an area [***16] attains the 1-hour standard,

those provisions will no longer apply and the area's

implementation of the new 8-hour standard would be

governed only by the provisions of Subpart 1 of Part D of

Title I." Id. EPA subsequently "published [this

interpretation] in the explanatory preamble to its final

ozone NAAQS under the heading, 'Final decision on the

primary standard.'" Whitman, 531 U.S. at 477-78 (citing

Final Ozone NAAQS Rule, 62 Fed. Reg. at 38,873).

Based on this chronology, the Supreme Court found

EPA's ozone implementation policy was final and

reviewable, explaining:

The EPA's "decisionmaking process,"

which began with the 1996 proposal and

continued with the reception of public

comments, concluded when the agency,

"in light of [these comments]," and in

conjunction with a corresponding directive

from the White House, adopted the

interpretation of Part D at issue here. Since

that interpretation issued, the EPA has

refused in subsequent rulemakings to

reconsider it, explaining to disappointed

commenters that its earlier decision was

conclusive.

Whitman, 531 U.S. at 478-79 (citing 63 Fed. Reg. 31,014,

31,018-19 (1998)). The history of the PM2.5 standard

reveals no comparable decisionmaking [***17] process

regarding implementation. The Implementation

Memorandum Supplement did not even mention Subpart

1 or Subpart 4 in its discussion of the PM2.5

implementation--much less distinguish between them or

discuss their applicability vel non to implementation of

the PM2.5 standard. See 62 Fed. Reg. at 38,427-29

(section titled "Implementation of New PM2.5

NAAQS"). Nor did EPA thereafter overtly treat its

"interim" PM2.5 implementation policy as final when it

promulgated the 2007 and 2008 Final PM2.5

Implementation Rules challenged here. Accordingly, we

conclude the petitioners' challenge is timely and proceed

to EPA's substantive decision to implement the NAAQS

under Subpart 1.

B.

EPA contends that because Subpart 4 repeatedly

refers to PM10--rather than to PM2.5 or "particulate

matter" generally--the statutory language limits Subpart

4's applicability to implementation of the current PM10

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standard. Thus, by default, EPA contends, PM2.5 must be

implemented pursuant to the general (and less stringent6

implementation procedure in [*435] [**385] Subpart 1.

This argument ignores [*436] the plain meaning of the

statute and the lesson of Whitman.

6 For example, (1) Subpart 4 requires a

nonattainment area to be classified [***18] as

"moderate" and upon failure to attain to be

reclassified as "serious," 42 U.S.C. § 7513(a)-(c),

while under Subpart 1, EPA "may" but is not

required to classify a nonattainment area, id. §

7502(a)(1)(A); (2) under Subpart 4, a "serious"

attainment date may be extended only once (for a

maximum of 5 years) and only if the SIP includes

the "most stringent measures" included in any

state's SIP or achieved in any State and feasible

for the area, id. § 7513(e), while Subpart 1 allows

attainment date extensions of up to 10 years with

no "stringent measures" requirement therefor, id.

§ 7502(a)(2)(A); (3) Subpart 4 subjects a

"serious" nonattainment area that fails to timely

attain to a mandatory annual 5% pollutant

reduction, id. § 7513a(d), while Subpart 1

includes no such requirement; (4) Subpart 4

requires that "reasonable available control

measures" must be implemented within 4 years

after designation, id. § 7513a(a)(1)(C), while

Subpart 1 requires such measures be implemented

"as expeditiously as practicable," id. § 7502(c)(1);

and (5) Subpart 4 requires that best available

control measures be implemented no later than 4

years after an area is classified or reclassified as

"serious," [***19] id. § 7513a(b)(1)(B), while

Subpart 1 has no best available control measures

requirement.

Before the Congress enacted Subpart 4, EPA had

promulgated a single particulate matter standard--the

PM10 standard--which encompassed all particulate

matter with a diameter of 10 micrometers or

less--including both coarse and fine particulate matter,

that is, particulate matter now governed by both the

PM10 and PM2.5 standards--and the 1990 CAA

amendments adopted this broad meaning in defining

"PM10." 1987 PM NAAQS Revisions, 52 Fed. Reg. at

24,639 ("The Administrator . . . has decided to replace

[Total Suspended Particles] as the particle indicator for

the primary standards with a new indicator that includes

only those particles less than a nominal 10 [micrometers]

in diameter. . . . In defining the standards for particulate

matter, this new indicator is termed PM10."); 42 U.S.C. §

7602(t) ("The term 'PM-10' means particulate matter with

an aerodynamic diameter less than or equal to a nominal

ten micrometers . . . ."). Thus, by its express terms,

Subpart 4, when enacted, governed all PM10 particles,

including those now denominated PM2.5. The scope of

the statutory definition--and consequently of Subpart

[***20] 4's application--did not change when EPA

subdivided PM10 by regulation. As the Whitman Court

made clear, the intent of the 1990 amendments was to

limit the broad implementation discretion Subpart 1 had

previously granted EPA. Cf. Whitman, 531 U.S. at 484

("The principal distinction between Subpart 1 and

Subpart 2 is that the latter eliminates regulatory discretion

that the former allowed."). It makes no sense then that the

Congress would have wanted EPA to relax Subpart 4's

more stringent, nondiscretionary requirements for

implementing the PM2.5 standard at the same time EPA

decided to strengthen the PM2.5 standard itself based on

"evidence from numerous health studies demonstrating

that serious health effects are associated with exposures

to elevated levels of PM2.5." PM2.5 Implementation

Rule, 72 Fed. Reg. at 20,586; see also id. at 20,586-87

("Epidemiological studies have shown statistically

significant correlations between elevated PM2.5 levels

and premature mortality. Other important effects

associated with PM2.5 exposure include aggravation of

respiratory and cardiovascular disease (as indicated by

increased hospital admissions, emergency room visits,

absences from school or work, [***21] and restricted

activity days), changes in lung function and increased

respiratory symptoms, as well as new evidence for more

subtle indicators of cardiovascular health. Individuals

particularly sensitive to PM2.5 exposure include older

adults, people with heart and lung disease, and

children.").7 Notwithstanding [**386] the plain meaning

of the statutory language and the force of Whitman,

8 EPA

offers several unconvincing arguments to support

implementing the new PM2.5 standard pursuant to

Subpart 1 rather than Subpart 4.

7 The regulations' treatment of precursors

provides a useful example of how the Agency has

used Subpart 1 to establish a less stringent

implementation regime than envisioned by

Subpart 4. Ammonia is a precursor to fine

particulate matter, making it a precursor to both

PM2.5 and PM10. For a PM10 nonattainment

area governed by Subpart 4, a precursor is

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presumptively regulated. See 42 U.S.C. §

7513a(e). But under the PM2.5 rules challenged

here, the EPA established a rebuttable

presumption against regulating ammonia unless a

State or the EPA "provides an appropriate

technical demonstration" that shows emissions

from ammonia "significantly contribute to PM2.5

concentration in the [***22] nonattainment area."

40 C.F.R. § 51.1002(c)(4)(i). When Congress

enacted Subpart 4, it sought to end this

administrative gamesmanship.

8 EPA offers several grounds to distinguish

Whitman--none of them persuasive. First EPA

notes that the text of Subpart 2 refers generically

to "ozone" while Subpart 4's text refers

specifically to PM10, EPA Br. 36--but Subpart 4's

title refers generically to "Particulate Matter" and,

as we have noted, when the 1990 amendments to

the CAA were enacted, PM10 included PM2.5

under both the new statutory definition and the

existing EPA definition. Second, EPA argues that

Subpart 4's provisions do not "comprehensively

prescribe[] classifications and attainment dates for

all particulate matter nonattainment areas." Br. of

Resp't 37 (emphasis in original). Subpart 4 may

not be as comprehensive as Subpart 2 but its

requirements are specific, more stringent and far

less discretionary than Subpart 1. See supra note

6. Third, EPA contends that in contrast to

Whitman, EPA's application of Subpart 1 to

PM2.5 does not render Subpart 4 "utterly

nugatory" because Subpart 4 still applies to the

remaining PM10 standard. Br. of Resp't 37

(quoting Whitman, 531 U.S. at 484). [***23] But

if EPA's interpretation stands, Subpart 4 will be

"utterly nugatory" with respect to implementation

of the PM2.5 standard--notwithstanding the

Congress expressly directed the standard

applicable to all PM10 particles, including PM25,

be regulated under Subpart 4.

First, EPA claims Subpart 4 "contains requirements

that are expressly based upon the form of the PM10

NAAQS." Br. of Resp't 31. This may be true but Subpart

4 also expressly governs implementation of the "PM-10"

standard, see 42 U.S.C. §§ 7513-7513b, and the Act

defines "PM-10" as "particulate matter with an

aerodynamic diameter less than or equal to a nominal ten

micrometers," 42 U.S.C. § 7602(t). Thus, under Chevron

step 1, EPA must implement all standards applicable to

PM10--including its PM2.5 standards--pursuant to

Subpart 4.

Second, EPA urges that because in the 1987 PM

NAAQS Revisions, it "had considered whether to

establish a separate NAAQS for fine particles, using

PM2.5 as the indicator," the Congress should have

foreseen that it might do so later. Br. of Resp't 32. It is

not at all clear that the Congress should have so

foreseen--EPA cites a single, vague footnote to support

its claim the Congress was on notice such [***24] a

change was likely. Id. at 32 (citing 52 Fed. Reg. at 24,639

n.2 ("Particles in ambient air usually occur in two

somewhat overlapping size distributions, fine (diameter

less than 2.5 [micrometers]) and coarse (diameter larger

than 2.5 [micrometers]. The two size fractions tend to

have different origins and composition." (staff document

citation omitted)). But even were such notice clear, it

does not follow that the Congress therefore intended that

a separate PM2.5 standard (if promulgated) be exempt

from Subpart 4's requirements. As in Whitman, the

possibility of such a change suggests only that gaps

resulting therefrom might "prevent us from concluding

that Congress clearly intended [the specific pollutant

subpart] to be the exclusive, permanent means of

enforcing a revised ozone standard in nonattainment

areas." Whitman, 531 U.S. at 484 (emphasis added). It

does not render "utterly nugatory" the restrictions that the

1990 amendments imposed on EPA's discretion in

implementing the particulate matter standards for all

particles 10 micrometers or less in diameter. See id. As

the Supreme Court observed regarding Subpart 2, "[a]

plan reaching so far into the future was not enacted to

[***25] be abandoned the next time the EPA reviewed

the [pollutant's] standard--which Congress [*437]

[**387] knew could happen at any time." Id. at 485.

EPA also argues that the Congress "could have easily

used the general term 'particulate matter,' rather than the

specific term 'PM-10.'" Br. of Resp't 33. That the

Congress could have done so does not negate the reality

that the "PM10" standard to which the Congress referred

in fact included fine PM2.5 (both under the 1987 Rule

and the 1990 statutory definition).

In a final Chevron step 1 effort, EPA asserts that the

legislative history makes the Congress's intent clear.

Assuming legislative history could override the plain,

unambiguous directive of Subpart 4, the history cited

here is unconvincing. EPA relies on a single

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congressman's statement: "'The Title I PM-10 provisions

of H.R. 3030 somewhat reschedule the attainment dates

that would otherwise apply under the PM-10 standards as

promulgated by EPA.'" Br. of Resp't 39 (quoting A

Legislative History of the Clean Air Act Amendments of

1990, at 2996 (Comm. Print 1993) (statement of Rep.

John Murtha)). This statement avails EPA nought.

"[P]utting to one side the fact that this was the statement

of a single [***26] [member of Congress], . . . it is not

necessarily inconsistent with" the petitioners' view that

Subpart 4 continues to apply to PM2.5 standards. See

Grand Canyon Air Tour Coal. v. FAA, 154 F.3d 455,

474, 332 U.S. App. D.C. 133 (D.C. Cir. 1998). At the

time the statement was uttered, "the PM-10 standards as

promulgated by EPA" applied to all particulate matter

having a diameter equal to or less than 10

micrometers--including what is now denominated

PM2.5.9 See 1987 PM NAAQS Revisions, 52 Fed. Reg.

at 24,639.

9 Moreover, "judges must exercise extreme

caution before concluding that a statement made

in floor debate, or at a hearing, or printed in a

committee document may be taken as statutory

gospel, in light of the endemic interplay, in

Congress, of political and legislative

considerations likely unrelated to the interpretive

tasks of a court." Tex. Mun. Power Agency v.

EPA, 89 F.3d 858, 875, 319 U.S. App. D.C. 217

(D.C. Cir. 1996) (per curiam) (quotation marks

and alterations omitted). Here, it is hard to ignore

"the irony that [EPA] points to the same floor

statement that the [petitioners] contend[] supports

[their] opposite view." Grand Canyon Air Tour

Coal., 154 F.3d at 474 (emphasis in original).

EPA additionally argues that its "reading [***27] of

the act is, at minimum, a 'permissible' interpretation

entitled to deference under Chevron step two." Br. of

Resp't 41 (upper case lowered). This argument is

foreclosed, however, under Chevron step 1 because the

statute is plain on its face.

For the foregoing reasons, we grant the petitions for

review of the Final Clean Air Fine Particle

Implementation Rule, 72 Fed. Reg. 20,586 (Apr. 25,

2007), and the Implementation of the New Source

Review (NSR) Program for Particulate Matter Less Than

2.5 Micrometers (PM2.5), 73 Fed. Reg. 28,321 (May 16,

2008). We remand to EPA to re-promulgate these rules

pursuant to Subpart 4 consistent with this opinion.10

10 In light of our disposition, we need not

address the petitioners' challenge to the

presumptions in 40 C.F.R. § 51.1002(c)(3)-(4)

that volatile organic compounds and ammonia are

not PM2.5 precursors as Subpart 4 expressly

governs precursor presumptions. See 42 U.S.C. §

7513a(e). Moreover, we decline the petitioners'

invitation to set a deadline for EPA upon remand

or to retain jurisdiction pending such action. See

Natural Res. Def. Council v. EPA, 489 F.3d 1364,

1375, 376 U.S. App. D.C. 528 (D.C. Cir. 2007)

("We decline to set a two year limit on EPA's

proceedings [***28] on remand as the NRDC

requests; mandamus affords a remedy for undue

delay."); North Carolina v. EPA, 550 F.3d 1176,

1178, 384 U.S. App. D.C. 70 (D.C. Cir. 2008)

(per curiam) (declining invitation to "impose a

definitive deadline by which EPA must correct

[clean air rule's] flaws" and reminding petitioners

of availability of mandamus).

So ordered.

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