United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Filed: December 20, 2012

No. 09-1322

COALITION FOR RESPONSIBLE REGULATION, INC., ET AL.,

PETITIONERS

v.

ENVIRONMENTAL PROTECTION AGENCY,

RESPONDENT

STATE OF MICHIGAN, ET AL.,

INTERVENORS

Consolidated with 10-1024, 10-1025, 10-1026, 10-1030,

10-1035, 10-1036, 10-1037, 10-1038, 10-1039, 10-1040,

10-1041, 10-1042, 10-1044, 10-1045, 10-1046, 10-1234,

10-1235, 10-1239, 10-1245, 10-1281, 10-1310, 10-1318,

10-1319, 10-1320, 10-1321

No. 10-1073

COALITION FOR RESPONSIBLE REGULATION, INC., ET AL.,

PETITIONERS

v.

ENVIRONMENTAL PROTECTION AGENCY,

RESPONDENT
2

AMERICAN FROZEN FOOD INSTITUTE, ET AL.,

INTERVENORS

Consolidated with 10-1083, 10-1099, 10-1109, 10-1110,

10-1114, 10-1118, 10-1119, 10-1120, 10-1122, 10-1123,

10-1124, 10-1125, 10-1126, 10-1127, 10-1128, 10-1129,

10-1131, 10-1132, 10-1145, 10-1147, 10-1148, 10-1199,

10-1200, 10-1201, 10-1202, 10-1203, 10-1206, 10-1207,

10-1208, 10-1210, 10-1211, 10-1212, 10-1213, 10-1216,

10-1218, 10-1219, 10-1220, 10-1221, 10-1222

No. 10-1092

COALITION FOR RESPONSIBLE REGULATION, INC., ET AL.,

PETITIONERS

v.

ENVIRONMENTAL PROTECTION AGENCY,

RESPONDENT

LANGBOARD, INC. - MDF, ET AL.,

INTERVENORS

Consolidated with 10-1094, 10-1134, 10-1143, 10-1144,

10-1152, 10-1156, 10-1158, 10-1159, 10-1160, 10-1161,

10-1162, 10-1163, 10-1164, 10-1166, 10-1182
3

No. 10-1167

AMERICAN CHEMISTRY COUNCIL,

PETITIONER

v.

ENVIRONMENTAL PROTECTION AGENCY AND LISA PEREZ

JACKSON, ADMINISTRATOR, U.S. ENVIRONMENTAL

PROTECTION AGENCY,

RESPONDENTS

CHAMBER OF COMMERCE OF THE UNITED STATES OF

AMERICA, ET AL.,

INTERVENORS

Consolidated with 10-1168, 10-1169, 10-1170, 10-1173,

10-1174, 10-1175, 10-1176, 10-1177, 10-1178, 10-1179,

10-1180

 On Petitions for Rehearing En Banc 

 ______

Before: SENTELLE*, Chief Judge, and HENDERSON,

ROGERS*,TATEL*, GARLAND, BROWN*, GRIFFITH, and

KAVANAUGH*, Circuit Judges.
4

O R D E R 

The petition of the Chamber of Commerce of the United

States of America, joined by the State of Alaska, Peabody

Energy Company, Southeastern Legal Foundation, et al., State

Petitioners and Intervenors for Petitioners, for rehearing en

banc; and the petition of the National Association of

Manufacturers, et al. for rehearing en banc in No. 10-1073, et al.

and No. 10-1167, et al., and the responses to the petitions were

circulated to the full court, and a vote was requested. 

Thereafter, a majority of the judges eligible to participate did not

vote in favor of the petitions. Upon consideration of the

foregoing, it is

ORDERED that the petitions be denied.

FOR THE COURT: 

Mark J. Langer, Clerk 

BY: /s/ 

Jennifer M. Clark 

Deputy Clerk 

*Circuit Judges Brown and Kavanaugh would grant the petitions

for rehearing en banc. 

* A statement by Chief Judge Sentelle and Circuit Judges

Rogers and Tatel, concurring in the denials of rehearing en banc,

is attached. 

* A statement by Circuit Judge Brown, dissenting from the

denials of rehearing en banc, is attached.

*A statement by Circuit Judge Kavanaugh, dissenting from the

denials of rehearing en banc, is attached. 
SENTELLE, Chief Judge, ROGERS, Circuit Judge, and 

TATEL, Circuit Judge, concurring in the denials of rehearing 

en banc: In dissenting from the denials of rehearing en banc, 

Judge Brown primarily takes issue with EPA’s Endangerment 

Finding. But as she candidly acknowledges, see Dissenting 

Op. at 2 (Brown, J.), her quarrel is with the Supreme Court. In 

Massachusetts v. EPA, 549 U.S. 497 (2007), the Court

expressly held that the Clean Air Act’s “sweeping definition 

of ‘air pollutant’ ” unambiguously includes greenhouse gases. 

See id. at 528–29. Moreover, in so holding, the Court 

expressly rejected many of the arguments her dissent now 

presses. In particular, it rebuffed EPA’s attempt to use 

“postenactment congressional actions and deliberations” to 

obscure “the meaning of an otherwise-unambiguous statute,” 

id. at 529, and found EPA’s reliance on FDA v. Brown & 

Williamson Tobacco Corp., 529 U.S. 120 (2000), “similarly 

misplaced,” Massachusetts v. EPA, 549 U.S. at 530. Seeking

to revive the Brown & Williamson argument, Judge Brown 

suggests that the Court never considered the “far-reaching 

effects” of extending greenhouse gas regulation to stationary 

sources. See Dissenting Op. at 18 (Brown, J.). But this is 

inaccurate—the briefs before the Court explicitly raised the 

argument that interpreting “air pollutant” to include 

greenhouse gases could have tremendous consequences for

stationary-source regulation. See, e.g., Brief of Respondent 

CO2 Litigation Group, Massachusetts v. EPA, 549 U.S. 497 

(2007) (No. 05-1120), 2006 WL 3043971 at *19–*31. 

To the extent Judge Brown attempts to bypass 

Massachusetts v. EPA by focusing on the statutory condition

that air pollution “reasonably be anticipated to endanger

public health or welfare,” 42 U.S.C. § 7521(a)(1) (emphasis 

added), her quarrel is not just with the Supreme Court, but 

also with EPA’s assessment of the science. Of course, we 

agree that the statute requires EPA to find a particular causal 

nexus between the pollutant and the harm in order to regulate.

See Dissenting Op. at 9 (Brown, J.). But that is exactly what 
2

EPA did: it found that “greenhouse gases in the atmosphere 

may reasonably be anticipated both to endanger public health 

and to endanger public welfare.” Endangerment and Cause or 

Contribute Findings for Greenhouse Gases Under Section 

202(a) of the Clean Air Act, 74 Fed. Reg. 66,496, 66,497 

(Dec. 15, 2009). And, as the panel opinion explains, EPA’s 

scientific judgment about the causal relationship between 

greenhouse gases and climate change is a scientific 

determination entitled to “an extreme degree of deference.” 

Coalition for Responsible Regulation v. EPA, 684 F.3d 102,

120 (D.C. Cir. 2012) (quoting American Farm Bureau 

Federation v. EPA, 559 F.3d 512, 519 (D.C. Cir. 2009)). The 

dissent's suggestion that EPA was somehow statutorily 

precluded from finding the requisite nexus between 

greenhouse gases and harm to public health and welfare, see 

Dissenting Op. at 10–11 (Brown, J.), is belied by the Supreme 

Court's decision to remand precisely this question. See 

Massachusetts v. EPA, 549 U.S. at 532–35. 

Judge Kavanaugh’s dissent relates to the scope of the 

Prevention of Significant Deterioration (“PSD”) program, an 

aspect of the panel opinion Judge Brown also rejects.

Specifically, Judge Kavanaugh disagrees with EPA’s 

longstanding interpretation of the term “any air pollutant,” 42 

U.S.C. § 7479(1), arguing that, in the context of the PSD 

program, “any air pollutant” refers not to all pollutants 

regulated under the Clean Air Act, but only to the six NAAQS 

pollutants. Because taking the statute at its word and 

interpreting “any air pollutant” to include greenhouse gases 

would lead to what he considers absurd results, Judge 

Kavanaugh insists that EPA and this Court are obligated to 

read “any air pollutant” more narrowly. See Dissenting Op. at 

3–10 (Kavanaugh, J.). This argument, however, hinges on the 

proposition that both readings are plausible interpretations of 

an ambiguous statutory provision. See Dissenting Op. at 2–3, 
3

10 (Kavanaugh, J.). But as the panel opinion explains at 

length, the statute is clear. See Coalition for Responsible 

Regulation, 684 F.3d at 132–44. Congress did not say “certain 

‘air pollutants.’ ” Dissenting Op. at 2 (Kavanaugh, J.). It said 

“any air pollutant,” and it meant it. See Coalition for 

Responsible Regulation, 684 F.3d at 136. Thus, unlike the 

unreasonable interpretation rejected in Kloeckner v. Solis, No. 

11-184, slip op. at 7–13 (U.S. 2012), the panel’s interpretation 

of the statute is the only plausible one.

Moreover—and again, as the panel opinion explains at 

length, see Coalition for Responsible Regulation, 684 F.3d at 

135–36—considering “any air pollutant” in context buttresses 

rather than undermines the panel’s interpretation. The statute 

frames the purpose of the PSD program in broad—not 

NAAQS-specific—terms, emphasizing that the program’s 

goal is “to protect public health and welfare from any actual 

or potential adverse effect which . . . may reasonably be 

anticipate[d] to occur from air pollution.” 42 U.S.C. 

§ 7470(1). And although certain aspects of the program are 

specifically directed at NAAQS pollutants, see, e.g., id.

§ 7473(b)(4), the program as a whole plainly has a more 

expansive scope. For instance, covered sources are required to 

(1) install the best available control technology for “each 

pollutant subject to regulation under [the Act],” id.

§ 7475(a)(4) (emphasis added), and (2) demonstrate that they 

will not cause or contribute to “any . . . applicable emission 

standard” under the Act, id. § 7475(a)(3) (emphasis added).

In the end, we agree that “the question here is: Who 

Decides?” Dissenting Op. at 18 (Kavanaugh, J.). We also 

agree that “Congress (with the President) sets the policy 

through statutes, agencies implement that policy within 

statutory limits, and courts in justiciable cases ensure that 

agencies stay within the statutory limits set by Congress.” 
4

Dissenting Op. at 18 (Kavanaugh, J.). Here, Congress spoke 

clearly, EPA fulfilled its statutory responsibilities, and the 

panel, playing its limited role, gave effect to the statute’s plain 

meaning. See Chevron, U.S.A., Inc. v. NRDC, 467 U.S. 837, 

842–43 (1984) (“If the intent of Congress is clear, that is the 

end of the matter; for the court, as well as the agency, must 

give effect to the unambiguously expressed intent of 

Congress.”).

To be sure, the stakes here are high. The underlying 

policy questions and the outcome of this case are undoubtedly 

matters of exceptional importance. The legal issues presented, 

however, are straightforward, requiring no more than the 

application of clear statutes and binding Supreme Court 

precedent. There is no cause for en banc review.
BROWN, Circuit Judge, dissenting from the denial of 

rehearing en banc: In the summer of 1974, while waiting to 

start classes at UCLA, I was lucky enough to obtain a summer 

job house sitting in the pleasant, upscale neighborhood of 

Pasadena. Known mostly for its Rose Parade and Rose Bowl, 

Pasadena is one of the more scenic exurbs of Los Angeles. I 

inhabited a sparsely furnished, modest-but-pricey bungalow 

set among the lush landscape typical of southern California. 

This is a place where Birds of Paradise grow ten feet tall and 

the magenta blossoms of Bougainvillea fall like lavish 

draperies from redwood garden trellises. After staying in the 

house more than a month and spending a restless night 

listening to the agitated thrashings of the jacaranda trees in a 

fitful wind, I stumbled bleary-eyed into the kitchen, looked 

out the window, and stopped — utterly dumbfounded. There 

— looking like it was but a few feet beyond the back fence — 

stood a mountain. Not a foothill. Not an unobtrusive mesa. 

A mountain! Closer inspection revealed not a lone majestic 

peak, but a whole mountain range I later identified as the San 

Gabriels. In those days, the air in the Los Angeles basin was 

so thick with smog that a mountain, or even a nearby 

mountain range, could simply disappear. 

Although the Los Angeles basin was among the most 

notorious examples of the phenomenon, it was by no means 

unique and certainly not the worst. It was this crisis of 

ambient air quality that precipitated the enactment of the 

Clean Air Act (CAA). But as the CAA’s history, language, 

and structure make clear, Congress never intended the Act to 

serve as an environmental cure-all. It was targeted legislation 

designed to remedy a particular wrong: the harmful direct 

effects of poisoned air on human beings and their local 

environs. This is what Congress understood as “air pollution 

which may reasonably be anticipated to endanger public 

health” in the tailpipe emissions provision, 42 U.S.C. § 

7521(a)(1). The Supreme Court in Massachusetts v. EPA, 

549 U.S. 497 (2007), however, concluded otherwise. In dicta 
2 

too suggestive to ignore, the Court implicitly assumed that 

climate change could provide the basis for an endangerment 

finding in the tailpipe context. See id. at 532–33. 

Bound as I am by Massachusetts, I reluctantly concur with 

the Panel’s determination that EPA may regulate GHGs in 

tailpipe emissions. But I do not choose to go quietly. 

Because the most significant regulations of recent memory 

rest on the shakiest of foundations, Part I of this statement 

engages Massachusetts’s interpretive shortcomings in the 

hope that either Court or Congress will restore order to the 

CAA. Part II, by contrast, reflects my belief that 

Massachusetts does not compel the same result for Title V 

and the Prevention of Significant Deterioration of Air Quality 

(PSD) program. Although I agree with Judge Kavanaugh’s 

dissent, Coal. for Responsible Regulation v. EPA, Nos. 09-

1322, et al. (Kavanaugh, J., dissenting from denial of 

rehearing en banc), I approach the inflection point from a 

slightly different perspective. Part III concludes with a brief 

note on standing. 

Because I would vote for the full court to consider the 

propriety of extending Massachusetts to Title V and the PSD 

program, I respectfully dissent from this denial of rehearing 

en banc. 

I. 

A. 

The origins of the Clean Air Act are closely tied to fatal 

fogs and deadly air inversions that, for much of early postindustrial history, seemed to be the inevitable consequence of 

economic progress. See Arnold W. Reitze, Jr., A Century of 

Air Pollution Control Law: What’s Worked; What’s Failed; 
3 

What Might Work, 21 ENVTL. L. 1549, 1575 (1991).1

 Initially 

regulated at the local and state level, air pollution became the 

focus of the federal government only after World War II. See

id. at 1585–86. In October 1948, a severe temperature 

inversion in the industrial city of Donora, Pennsylvania 

increased air pollution to such an extent that traffic “ ‘was 

virtually stopped because of lack of visibility.’ ” The 

inversion killed 20 people, id., and prompted the federal 

government to begin researching air pollution. Id. at 1586. 

By 1961, President Kennedy included a plea for “an effective 

air pollution program” in his Special Message on the Natural 

Resources. Id. Public pressures for legislation only increased 

when a “Killer Smog” engulfed London in December 1962, 

killing at least 340, and a similar inversion in New York City 

allegedly claimed the lives of 200. Id. Eventually, legislation 

recommended by President Kennedy in February 1963 led to 

the enactment of the CAA, which President Johnson signed 

into law on December 17, 1963. Id. at 1586–87. Seven years 

later, President Nixon signed The Clean Air Amendments of 

1970. The 1970 Amendments authorized the EPA to prescribe 

national ambient air quality standards (NAAQS) and created 

the statutory framework that still exists today. 

 

B. 

It was no happy accident that congressional draftsmen 

titled the legislation the “Clean Air Act.” Ambient air quality 

was the point, purpose, and focus of the CAA. Congress had 

set its sights on the “dirty, visible ‘smokestack’ emissions,” 

136 CONG. REC. H2771-03 (1990) (statement of Rep. Roe), 

 1

 Inversions, sometimes known as “Londoners,” occur “when a 

layer of hot air warmed by . . . water exists above cooler groundlevel air and traps smoke and particulate matter under the warmer 

air.” Id.
4 

and smog caused by vehicle emissions. The CAA was the 

means by which Congress would grapple with urban air 

pollution and its attendant health effects, including impaired 

breathing, heart disease, lung damage and lung disease, and 

even death. If pollution was the problem, these ills were the 

specific harms Congress sought to combat. Even a cursory 

glance at the legislative history, with its numerous charts, 

graphics, and statistics detailing cancer and death rates, will 

bear this point out. See, e.g., Hearings on Air Pollution — 

1968 Before the Subcomm. on Air and Water Pollution of the 

Sen. Comm. on Pub. Works, 90th Cong. 2nd Sess., pt. 2, 608–

20 (1968) (statement of Dr. Samuel S. Epstein, Children’s 

Cancer Research Foundation.) (“Air Pollution — 1968”). 

With the enactment of the 1990 Amendments, Congress 

expanded the Act beyond its singular emphasis on urban air 

quality to address hazardous — i.e., toxic — air pollutants, 

acid rain, and stratospheric ozone. In regulating hazardous 

pollutants, Congress reemphasized the need for a close and 

tangible nexus between pollutant and harm. The legislative 

record, for example, continued to conceive of dangers in 

terms of their direct effects on human health and well-being. 

See, e.g., S. Rep. No. 101-228, at 3388 (1989), reprinted in 

1990 U.S.C.C.A.N. 3385 (“Air pollution can silently damage 

our lungs and heart or act swiftly in the case of exposure to 

toxic air pollutants. Rigorous regulation of toxic air 

pollutants is needed to avoid risk of serious, irreversible 

damage to human health.”). To the extent the regulation of 

stratospheric ozone and acid rain suggest a broader nexus 

between pollutant and harm to human health, the very 

particular way in which Congress handled these exceptions 

goes a long way toward proving the rule: Congress only 

expands the CAA through considered legislative acts. 
5 

In addressing these transnational phenomena, the 

legislature did not spin regulations out of whole cloth. With 

ozone concerns, for example, Congress developed solutions 

through international negotiations, the implementation of 

which led to the creation of a separate title of the CAA. See 

NRDC v. EPA, 464 F.3d 1, 3 (D.C. Cir. 2006). Likewise, 

years of contentious discussions with Canada helped bring 

about the acid rain provisions in the 1990 Amendments. See 

generally Dennis A. Leaf, Intergovernmental Cooperation: 

Air Pollution from an U.S. Perspective, 18 CAN.-U.S. L.J. 245 

(1992). Simply put, when Congress became aware of new 

dangers, it acted judiciously in crafting workable remedies 

that, when they obtained the necessary political support, were 

worked into their own discrete provisions under the Act. 

Neither Congress nor the EPA attempted to force these 

distinct problems into existing, ill-suited regulatory schemes. 

 Congressman Waxman, one of the strongest proponents 

of stringent air pollution controls and a key force behind the 

1990 Amendments, has stated that “in recent experience, no 

legislation has received more scrutiny during its 

consideration.” The Honorable Henry A. Waxman, An 

Overview of the Clean Air Act Amendments of 1990, 21 

ENVTL. L. 1721, 1724 (1991). Hyperbole or not, the 

admission is telling. The history of the CAA is one of hardfought incremental gains through which Congress remedied 

particular environmental wrongs with tailored remedies. 

Said the Congressman: 

Discrete and extensive new programs are included to 

grapple with high ambient pollution levels (urban and 

regional smog), hazardous air pollution, acid rain, and 

depletion of the stratospheric ozone layer. Each of these 

programs [was] tailored to the problem it [sought] to 

address, and each [was] quite different in its approach.” 
6 

Id. at 1811. Political necessity has forced Congress to 

calibrate its amendments to the CAA with great specificity 

and care. Where our Representatives have acted with such 

caution, any suggestion that Congress has — through a single 

word — conferred upon EPA the authority to steamroll 

through Congressional gridlock, upend the Senate’s rejection 

of the Kyoto Protocol, and regulate GHGs for the whole of 

American industry must necessarily fail. The legislature, 

recall, does not “hide elephants in mouseholes.” Whitman v. 

Am. Trucking Assocs., 531 U.S. 457, 468 (2001). 

But we needn’t rely on interpretative canons alone to 

make this point. In drafting the 1990 Amendments, Congress 

considered — and expressly rejected — proposals authorizing 

EPA to regulate GHGs under the CAA. See S. Rep. No. 101-

228, at 377 (1989), as reprinted in 1990 U.S.C.C.A.N. 3385, 

3760. Even the Executive objected that an attempt to control 

Carbon Dioxide (CO2) emissions — emissions not harmful to 

health — in order to prevent global warming was premature. 

See Administration’s Amendments — Hearings Before the 

Subcomm. On Health and the Env’t of the Comm. on Energy 

and Commerce, 101st Cong., 1st Sess. (1989) (includes Bush 

Administration Report on S. 1630). The Executive’s critique 

noted that “unilateral action aimed at addressing a global 

problem” through a standard limiting tailpipe emissions 

would not be an effective means of safeguarding the global 

environment and would “necessarily punish national 

interests.” Id. at 792, 813. 

That Congress has never deviated from its decision to not 

regulate GHGs under the CAA was not for lack of 

opportunity. Congress has considered and rejected countless 

other bills in the years since the 1990 Amendments that would 

have authorized GHG regulation. By one estimate, 
7 

Congressmen have proposed over 400 bills concerning GHGs 

between 1990 and 2009. See Abigail R. Moncrieff, 

Reincarnating the “Major Questions” Exception to Chevron 

Deference As A Doctrine of Noninterference (or Why 

Massachusetts v. EPA Got It Wrong), 60 ADMIN. L. REV. 593, 

636–37 (2008) (tracking proposals). Congress’s inability to 

break this nearly quarter-century long deadlock is incredibly 

suggestive: this is not an area of policymaking where the 

legislature has acted rashly or unthinkingly in delegating 

authority to agencies. 

At bottom, Congress understood the dangers of “any air 

pollutant” in § 7521(a)(1) in terms of the ill-effects caused 

those who inhale the pollutants, not the broad, attenuated 

consequences of climate change. The CAA was drafted not to 

combat the threat of flooding or the menace of heat waves, 

see Endangerment and Cause of Contribute Findings for 

Greenhouse Gases, 74 Fed. Reg. 66,496, 66,526 (Dec. 15, 

2009) (“EPA Endangerment Finding”), but the choking, 

stifling, and degenerative effect of airborne pollutants on 

human beings and their affected localities. Congress has long 

quantified this harm in terms of mortality rates, see, e.g., Air 

Pollution — 1968, 564 (statement of Dr. Roger S. Mitchell, 

Director, Webb-Waring Institute for Medical Research), not 

acreage of “costal land” lost. Massachusetts, 549 U.S. at 522. 

To put matters pointedly: the injury sufficient to establish 

standing need not suffice to establish endangerment as well. 

Congress was of course free to circumvent this close 

cause-health effect nexus by devising a separate provision for 

GHG regulation, much as it did for stratospheric ozone, but it 

did no such thing. And nothing in the legislative history 

suggests that Congress has deviated from this status quo. 
8 

The plain language of the CAA only underscores the 

Act’s non-applicability to GHGs insofar as it requires the 

harm be of the sort “reasonably [] anticipated to endanger.” 

42 U.S.C. §7251(a)(1) — a term we know to have a discrete 

meaning. 

C. 

In the present case, this Court had “little trouble” 

disposing of the argument that the “PSD program is 

specifically focused solely on localized air pollution” because 

it is “quite clear . . . the PSD program was intended to protect 

against precisely the types of harms caused by greenhouse 

gases.” CRR Slp. Op. 62–63 (emphasis added). 

Massachusetts notwithstanding, this statement is a curious 

thing in light of the uncontradicted legislative history just 

discussed.2

 So too is the court’s reliance on the statutory text, 

particularly its finding that “the CAA expressly provides that 

effects on ‘welfare’ means ‘effects on . . . weather . . . and 

climate.’ ” Slp. Op. 62-63 (citing 42 U.S.C. § 7602(h)). 

As a textual matter, there is nothing “quite clear” about it. 

The Supreme Court has declared that GHGs like CO2 are 

pollutants within the meaning of the Act. Under the CAA, 

however, EPA can regulate a pollutant only if the 

administrator finds that the GHG causes or contributes to “air 

pollution which may reasonably be anticipated to endanger

public health or welfare.” 42 U.S.C. §7251(a)(1) (emphasis 

added). But in locating the CAA’s conception of “harm” in § 

7602(h), the definition of “welfare,” and not §7251(a)(1) 

 2

 As noted, the weather and climate issues targeted by the 

CAA involve direct, deleterious, localized effects caused by 

polluted air people breathe or suspended pollutants that may be 

deposited on land and crops by precipitation.
9 

generally, this court effectively skirted the operative statutory 

language — “may reasonably be anticipated” — and rendered 

it nugatory. This was in error. Section 7602(h) defines only 

the potential objects of harm; the “reasonably be anticipated” 

language of §7251(a)(1) supplies the requisite nexus between 

the pollutant and the objects of its harm. The two provisions 

must be read together if the statute is to be interpreted 

faithfully. To put matters another way, the “may reasonably 

be anticipated” language must do some analytical work in the 

endangerment determination lest it be deemed surplusage. 

See, e.g., Conference of State Bank Supervisors v. Conover, 

715 F.2d 604, 627 (D.C. Cir. 1983) (“[I]n construing a statute, 

we ‘are obliged to give effect, if possible, to every word 

Congress used.’ ” (quoting Reiter v. Sonotone Corp., 442 U.S. 

330, 339 (1979))). And in view of the CAA’s legislative 

history, the nature of that work is clear. 

In order to reasonably anticipate that a pollutant will 

contribute to air pollution that endangers public health or 

welfare, the Agency would have to conclude that pollution 

created by CO2 or another GHG is a reasonably direct cause 

of the damage to public health and welfare. To find that CO2

may ultimately endanger public health and welfare because 

sea levels will rise tells us nothing about whether CO2

concentrations in the ambient air directly harm public health 

and welfare. The ingredients of a Killer Smog are few and 

specific; the process through which an air inversion traps 

particulate matter close to the ground is well understood. 

With both there is a direct correlation between reducing the 

concentration of the pollutant and reducing the negative 

health effects. Questions of public health impacts from air 

pollution have consistently been based on the direct — that is, 

inhalational — effects of exposure to the pollutant. See, e.g., 

Joint Opening Brief of Non-State Petitioners and Supporting 

Intervenors at 58, Coal. for Responsible Regulation v. EPA, 
10 

No. 09-1322 (May 20, 2011); NRDC, Inc. v. EPA, 902 F.2d 

962, 973 (D.C. Cir. 1990) (concluding that EPA may not 

consider the health effects of increased unemployment when 

setting new health-based NAAQS) 

In contrast, any harm to human health and welfare flowing 

from climate change comes at the end of a long speculative 

chain. The dissent in Massachusetts pointed out that EPA had 

described in great detail the scientific uncertainty that 

precluded even forming a judgment as to whether greenhouse 

gases endanger public welfare. See 549 U.S. at 553–55 

(Scalia, J., dissenting). In that earlier defense of its refusal to 

form a judgment, EPA explained how predicting climate 

change involved a “complex web of economic and physical 

factors,” including: 

[o]ur ability to predict future global anthropogenic 

emissions of GHGs and aerosols; the fate of these 

emissions once they enter the atmosphere (e.g., what 

percentage are absorbed by vegetation or are taken up by 

the oceans); the impact of those emissions that remain in 

the atmosphere on the radiative properties of the 

atmosphere; changes in critically important climate 

feedbacks (e.g., changes in cloud cover and ocean 

circulation); change in temperature characteristics (e.g., 

average temperatures, shifts in daytime and evening 

temperatures); changes in other climatic parameters (e.g., 

shifts in precipitation, storms); and ultimately the impact 

of such changes on human health and welfare (e.g., 

increases or decreases in agricultural productivity, human 

health impacts). 

Id. If there can be this much logical daylight between the 

pollutant and the anticipated harm, there is nothing EPA is not 

authorized to do. If this finding is valid, in a world where six 
11 

degrees of separation is the compass of all humankind, the 

right endangerment finding would allow EPA to rule the 

world. But as this Court has noted before, EPA’s authority to 

regulate is constrained, not enlarged, by the relationship of the 

term “will endanger” to other sections of the CAA. See Ethyl 

v. EPA, 541 F.2d 1, 29 (D.C. Cir. 1976) (en banc). 

 

Of course, nothing here should be taken to imply that a 

particular GHG does not contribute to climate change. I mean 

only to suggest that a pollutant might contribute to the 

nebulous mélange of potential drivers of climate change 

without having any direct, deleterious impact within the 

meaning of the CAA. I emphasize too that this is not a 

problem with science. This is a problem of statutory 

interpretation. Climate change, with its geologic timeframe 

and its many uncertainties and imponderables, is and will 

probably remain a subject of some controversy. EPA finds 

the science sufficiently convincing for its purposes and it is 

entitled to a certain amount of deference on questions related 

to its technical expertise. But it is not necessary to quibble 

with the science of climate change to conclude that the 

endangerment finding fails on textual and logical terms. 

There is simply a point at which a difference in degree 

becomes a difference in kind and we have passed this point 

many times over in the course of this tortured litigation. The 

Supreme Court, however, has refused to recognize as much 

for tailpipe emissions. 

II. 

A. 

But we need not follow Massachusetts off the proverbial 

cliff and apply its reasoning to the unique Title V and PSD 

provisions not considered in that case. The cascading layers 
12 

of absurdity that flow from that interpretive exercise make 

clear that the plain language of the CAA compels no such 

result. As EPA’s own rulemaking documents have so 

unabashedly explained: 

To apply the statutory PSD and title V applicability 

thresholds literally to sources of GHG emissions would 

bring tens of thousands of small sources and 

modifications into the PSD program each year, and 

millions of small sources into the title V program. These 

extraordinary increases in scope of the permitting 

programs would mean that the programs would become 

several hundred-fold larger than what Congress appeared 

to contemplate. 

PSD and Title V Greenhouse Gas Tailoring Rule; Final Rule, 

75 Fed. Reg. 31,514, 31,533 (Jun. 3, 2010) (“Final Tailoring 

Rule”). Completely oblivious to the irony, EPA added: 

For our authority to take this action, we rely in part on the 

“absurd results” doctrine, because applying the PSD and 

title V requirements literally (as previously interpreted 

narrowly by EPA) would not only be inconsistent with 

congressional intent concerning the applicability of the 

PSD and title V programs, but in fact would severely 

undermine congressional purpose for those programs. 

Id. at 31,541–42. And again: 

[I]n this case because a literal reading of the PSD and 

title V applicability provisions results in insurmountable 

administrative burdens. Those insurmountable 

administrative burdens — along with the undue costs to 

sources — must be considered “absurd results” that 
13 

would undermine congressional purpose for the PSD and 

title V programs. 

Id. at 31,547. 

In precincts outside Washington, D.C., this litany might 

cause a regulator to pause and consider whether results so at 

odds with Congressional presuppositions could ever be 

justified as falling within the literal meaning of an enactment. 

EPA, however, proposes that the absurd result can be easily 

eliminated by ramping up and gradually phasing in the 

requirements. Faced with the choice of reconsidering the 

legitimacy of an endangerment finding that sets in motion 

such a cluster of chaos or rewriting the statute, the agency has 

blithely done the latter. This is an abuse of the absurdity and 

administrative necessity doctrines as neither can be invoked to 

preempt legislative prerogatives. Permitting a statute “to be 

read to avoid absurd results allows an agency to establish that 

seemingly clear statutory language does not express the 

‘unambiguously expressed intent of Congress,’ ” but it does 

not grant the agency “a license to rewrite the statute.” Mova 

Pharmaceuticals v. Shalala, 140 F.3d 1060, 1068 (D.C. Cir. 

1998). 

But that is not the worst of it. The real absurdity — 

apparently as invisible to the EPA as the San Gabriels once 

were to me — cannot be cured by phase in, no matter how 

subtly Byzantine. The real absurdity is that this 

unprecedented expansion of regulatory control, this epic 

overreach, may very well do more damage to the wellbeing of 

Americans than GHGs could ever do.3

 

 3 See, e.g., Joint Reply Br. of Non-State Petitioners and 

Supporting Intervenors at *1, No. 09-1322 (Nov. 14 2011) (“Nor 

does [EPA] dispute that the new rules will impose massive burdens 

on a struggling economy, or that its program of vehicle standards 
14 

 

B. 

 

A second, more elementary consideration counsels against 

the mechanical application of Massachusetts’s tailpipe 

emissions determination to these distinct CAA provisions: 

deference to Congress. 

As articulated in Food & Drug Administration v. Brown & 

Williamson Tobacco Corp., 529 U.S. 120 (2000), the 

Supreme Court’s “major questions” canon gives form to the 

judicial intuition so strongly implicated here: Congress should 

not be presumed to have deferred to agencies on questions of 

great significance more properly resolved by the legislature. 

If there was ever a regulation in recent memory more befitting 

such a presumption than the present, I confess I do not know 

of it. 

On familiar facts, the Supreme Court in Brown & 

Williamson rebuffed the FDA’s expansionist effort to bring 

tobacco products within its regulatory ambit. The agency’s 

regulation rested on a strained interpretation of the Food, 

Drug, and Cosmetic Act, 21 U.S.C. § 301 et seq., in which it 

defined nicotine as a “drug” and cigarettes and smokeless 

tobacco as “combination products” used to deliver nicotine to 

the body. See Brown & Williamson, 529 U.S. at 125–27. 

Applying Chevron U.S.A. Inc. v. Natural Resources Defense 

Council, 467 U.S. 837 (1984), the Court first considered the 

statutory structure. “[I]f tobacco products were within the 

FDA’s jurisdiction,” the majority concluded, the normal 

operation of the “Act would require the FDA to remove them 

from the market entirely,” and this would “contradict 

 

will affect global mean temperatures by no more than 0.01 degree 

Celsius by 2100”). 
15 

Congress’ clear intent as expressed in its more recent, 

tobacco-specific legislation.” Brown & Williamson, 359 U.S. 

at 143. As the present case confirms, such absurdity is all but 

inevitable where an agency attempts to regulate that which 

“simply do[es] not fit” within its regulatory scheme. Id. The 

Court next considered Congress’s 35 year history of tobaccospecific legislation, finding it “clear” that this “legislation has 

effectively ratified the FDA’s previous position that it lacks 

jurisdiction to regulate tobacco.” Id. at 156. 

 

The Court then closed its lengthy Chevron discussion 

with an appeal to first principles. The “inquiry into whether 

Congress has directly spoken to the precise question at issue,” 

the Court explained, “is shaped, at least in some measure, by 

the nature of the question presented.” Id. at 

159. Chevron deference operates on the assumption “that a 

statute’s ambiguity constitutes an implicit delegation,” but 

this tenuous fiction need not hold true in every 

situation. Id. “In extraordinary cases,” the Court went on, 

“there may be reason to hesitate before concluding that 

Congress has intended such an implicit 

delegation.” Id. (referencing Stephen Breyer, Judicial Review 

of Questions of Law and Policy, 38 ADMIN. L. REV. 363, 370 

(1986) (“A court may also ask whether the legal question is 

an important one. Congress is more likely to have focused 

upon, and answered, major questions, while leaving 

interstitial matters to answer themselves in the course of the 

statute’s daily administration”)).4

 4 MCI Telecommunications Corporation v. AT&T Co., 512 

U.S. 218 (1994), a case the Brown & Williamson Court found 

“instructive,” Brown & Williamson, 529 U.S. at 160, had advanced 

a similar logic. In concluding Congress had spoken to the meaning 

of the term “modify” as it appears in § 203(b) of the 

Communications Act of 1934, the Court rejected FCC’s far more 

expansive interpretation. The Court assumed in dicta that it was 
16 

 

Declaring Brown & Williamson “hardly [the] ordinary 

case,” the Court reasoned: 

 

Contrary to its representations to Congress since 1914, 

the FDA has now asserted jurisdiction to regulate an 

industry constituting a significant portion of the 

American economy. In fact, the FDA contends that, 

were it to determine that tobacco products provide no 

“reasonable assurance of safety,” it would have the 

authority to ban cigarettes and smokeless tobacco 

entirely. Owing to its unique place in American 

history and society, tobacco has its own unique 

political history. Congress, for better or for worse, has 

created a distinct regulatory scheme for tobacco 

products, squarely rejected proposals to give the FDA 

jurisdiction over tobacco, and repeatedly acted to 

preclude any agency from exercising significant 

policymaking authority in the area. Given this history 

and the breadth of the authority that the FDA has 

asserted, we are obliged to defer not to the agency's 

expansive construction of the statute, but to Congress’ 

consistent judgment to deny the FDA this power. 

 

Brown & Williamson, 529 U.S. at 159-60. 

 

In view of the language, structure, and history of the 

CAA, I am simply unable to distinguish this logic from the 

present case in any meaningful way. To the contrary, with 

 

“highly unlikely that Congress would leave the determination of 

whether an industry will be entirely, or even substantially, rateregulated to agency discretion — and even more unlikely that it 

would achieve that through such a subtle device as permission to 

‘modify’ rate-filing requirements.” MCI, 512 U.S. at 231. Certainly 

the same might be said here as well. 
17 

only the slightest of modifications one could rework the 

above text to apply to GHG emissions.5 

Although the Massachusetts Court distinguished Brown 

& Williamson, it did so only in the context of tailpipe 

emissions. Its reasoning does not extend to Title V and the 

PSD program. 

In the Court’s view, Brown & Williamson had “found 

critical at least two considerations that have no counterpart in 

[Massachusetts].” 549 U.S. at 531. First, whereas the 

regulation of tobacco under the FDCA would have necessarily 

led to a ban on tobacco products — an outcome that clashed 

with the “common sense” intuition that Congress never meant 

to remove those products from circulation — the expansion of 

EPA’s “jurisdiction would lead to no such extreme measures 

 5

 Perhaps: 

Contrary to its representations in Massachusetts v. EPA, the 

EPA has now asserted jurisdiction to regulate industries 

constituting a significant portion of the American economy. 

In fact, the EPA contends that, because greenhouse gases 

can be regulated as tailpipe emissions, it is obligated to 

regulate all stationary sources at admittedly “absurd” 

levels. Owing to its ubiquitous place in the planet’s life 

cycle, greenhouse gases have their own unique political 

history. Congress, for better or for worse, has declined to 

create a distinct regulatory scheme for greenhouse gases, 

squarely rejected proposals to give the EPA jurisdiction 

over greenhouse gases, and repeatedly acted to preclude 

any agency from exercising significant policymaking 

authority in the area. Given this history and the breadth of 

the authority that the EPA has asserted, we are obliged to 

defer not to the agency's expansive construction of the 

statute, but to Congress’ consistent judgment to deny the 

EPA this power. 
18 

[because] EPA would only regulate emissions” and “there is 

nothing counterintuitive to the notion that EPA can curtail the 

emission of substances that are putting the global climate out 

of kilter.” Id. But the Court spoke too soon. In the present 

litigation, EPA argued — and a Panel of this Court readily 

agreed — that in regulating tailpipe emissions under 42 

U.S.C. § 7521, it is obligated to regulate stationary sources 

under Title V and the PSD program as well. As a threshold 

matter, the Massachusetts Court never considered these farreaching effects. It limited its brief discussion on the merits 

to the tailpipe emissions question squarely before it. In this 

way, the Court never considered the differing ways in which 

the CAA regulates tailpipes and stationary sources. 

 

With tailpipe emissions, the inclusion of greenhouse 

gasses within the term “air pollutant” does not directly expand 

or contract the universe of vehicles and engines subject to the 

new standards. Consequently, the regulation’s impact will 

fall primarily on those manufacturers already complying with 

existing emission requirements. And even then, the Court 

explained, EPA “would have to delay any action ‘to permit 

the development and application of the requisite technology, 

giving appropriate consideration to the cost of 

compliance.’ ” Massachusetts, 549 U.S. at 531 (quoting 

§ 7521(a)(2)). Not so with the regulation of stationary 

sources. Insofar as 42 U.S.C. § 7479(1) defines “major 

emitting facility” to include those facilities with the “potential 

to emit” either 100 or 250 “tons per year or more of any air 

pollutant,” the statutory term is necessarily tied to CAA’s 

jurisdictional scope. Inescapably, then, the regulation of 

greenhouse gasses as “air pollutants” will radically expand the 

universe of covered entities far beyond Congress’s 

intentions. EPA’s decidedly extra-textual Tailoring Rule only 

confirms the ludicrousness of this result. Nor can it be said 

that the statutory safeguards operate in the same way as § 
19 

7521(a)(2). Permitting authorities may well be able to 

determine on a case-by-case basis what constitutes the “best 

available control technology” for a particular emitting facility, 

42 U.S.C. § 7479(3), but this is of little consolation for the 

small business owner who previously fell outside the CAA. 

At bottom, this outcome clashes with the “common sense” 

understanding that Congress would not have intended such a 

broad, unchecked expansion of the CAA to potentially 

millions of businesses from all walks of industry. The 

Supreme Court in Massachusetts simply did not have 

occasion to consider this absurd and “counterintuitive” 

outcome, but we do — and we must. 

 

Second, the Court determined that the “unbroken series 

of congressional enactments” referenced in Brown & 

Williamson “made sense only if adopted ‘against the backdrop 

of the FDA’s consistent and repeated statements that it lacked 

authority under the FDCA to regulate tobacco.’ ” 

Massachusetts, 549 U.S. at 531.6

 By contrast, EPA had “not 

identified any congressional action that conflicts in any way 

with the regulation of greenhouse gases from new motor 

vehicles.” Id. And even if it had, “Congress could not have 

acted against a regulatory ‘backdrop’ of disclaimers of 

regulatory authority” because “EPA had never disavowed the 

authority to regulate greenhouse gases, and in 1998 it in fact 

affirmed that it had such authority.” Id. When read in 

context, however, it is clear that the Court’s reasoning was 

building toward a wholly unspectacular point: because EPA’s 

legislative history failed to establish congressional intent with 

 6

 The suggestion here seems to be that Congress’s decision to 

regulate tobacco products would not, by itself, evince its intent to 

proscribe agencies from doing the same. Doing so in light of 

FDA’s statements, however, had the effect of implicitly codifying 

the agency’s long-held view. 
20 

the same weight and precision as Brown & Williamson, it did 

not justify “read[ing] ambiguity into a clear statute.” Id. 

That logic is inapplicable here. In the absence of lexical 

clarity — which the Court had found in in CAA’s “sweeping 

definition of ‘air pollutant,’ ” id. at 528 — we need legislative 

history and other indicia of congressional intent to inform our 

understanding of how GHGs are to be regulated under other 

CAA provisions.7 

The Massachusetts Court’s effort to distinguish Brown & 

Williamson is thus unavailing where we deal not with the 

definitional scope of “any pollutant” and tailpipe emissions, 

but the particular dangers Congress sought to combat in 

enacting Title V and the PSD program. When read in 

conjunction with the CAA’s history, structure, and language, 

the intuitive logic of the “major questions” doctrine makes 

clear that the Panel erred in extending Massachusetts. 

 7

 Consider the role of NAAQS in this regulatory system. EPA 

in Massachusetts had observed that NAAQS were established to 

“address air pollution problems that occur primarily at ground 

level” as well as “concentrations of substances in the ambient air 

and the related public health and welfare problems.” 

Massachusetts, 549 U.S. at 558–59 (Scalia, J., dissenting). EPA 

thus reasoned that the regulation of the buildup of CO2 in the upper 

reaches of the atmosphere — the process alleged to cause global 

climate change — was not akin to regulating the concentration of a 

substance that is polluting the air and was “beyond the scope of 

CAA’s authorization to regulate.” Id. In other words, EPA 

maintained that had Congress intended the CAA to regulate 

greenhouse cases and global climate change, it would have 

provided some better tool than NAAQS. That defense — offered in 

response to a demand to regulate tailpipe emissions — applies with 

even greater potency to Title V and the PSD program. In fact, 

although EPA now claims it is authorized to regulate greenhouse 

gases and global climate change, the agency acknowledges that the 

regulatory framework is as ill-suited to the task as ever. 
21 

Congress simply did not intend for EPA to convert the “Clean 

Air Act” to the “Warm Air Act” writ large. But that is exactly 

what the federal courts have done. 

As the Chief Justice observed in his Massachusetts 

dissent, impatience is not a juridical principle that can be 

sustained under our constitutional framework. See

Massachusetts, 549 U.S. at 535–36 (Roberts, C.J., dissenting). 

It certainly fares no better as a default measure of institutional 

choice under Chevron. As Massachusetts recognized, an 

agency can only exercise the authority Congress has delegated 

to it. See 549 U.S. at 534–35 (noting that EPA must “ground 

its reasons for action or inaction in the statute” and “exercise 

its discretion within defined statutory limits.”). Absurdity can 

never figure as an adequate substitute for authority in this 

threshold assessment. Nor can absurdity cure the agency’s 

failure to establish that the statute unambiguously compels its 

interpretation or that its interpretation, though discretionary, is 

actually consistent with statutory text, structure, and purposes. 

The agency seeks to avoid these pesky constraints here by 

invoking Massachusetts, but Article III judges cannot be a 

legitimate source of legislative authority. By deferring to the 

distorted claim of delegation advanced here, this Court has 

transformed Chevron from a useful, albeit accidental, 

touchstone into an idol to which we surrender our 

constitutional faith. 

III. 

In rejecting State Petitioners’ challenge to the Tailoring 

Rule for want of standing, the Panel invoked that famed 

preceptor of American civics, Schoolhouse Rock, to great 

effect. Slp. Op. at 79. (“As a generation of schoolchildren 

knows, ‘by that time, it’s very unlikely that [a bill will] 

become a law. It’s not easy to become a law.’ ”). I certainly 
22 

do not quarrel with such dispositive authority. Lawmaking is 

neither easy nor certain. In an ordinary case, the mere 

possibility of “corrective legislation” will not establish that 

redress is “likely, as opposed to merely speculative.” Lujan, 

504 U.S. at 561. But it bears repeating that this is not an 

ordinary case. Where the choice is between non-action or a 

confessedly “absurd” regulation poised to impress countless 

billions of dollars in costs on American industry, we have 

transcended the realm of the speculative. For once, the 

comparison with Massachusetts is apt. The Supreme Court 

found standing on the basis of an estimated rise in sea level of 

20 to 70 centimeters by the year 2100, see Massachusetts, 549 

U.S. at 542 (Roberts, C.J, dissenting) — a prediction based 

almost entirely on conjecture. Is it any more speculative to 

say that specific projections of billions of dollars in actual 

regulatory costs would not suffice to compel Congress to act? 

The Panel’s alternative contention fares better: because 

Congress could remedy the issue in countless ways, not all of 

which inure to State Petitioners’ benefit, the inquiry is 

“inherently speculative.” See Op. at 79. This argument 

benefits from the genuine uncertainty in Congress over what, 

if any, role EPA should play in GHG regulation. But therein 

lies a frighteningly obtuse logic. If EPA actions are ultra 

vires precisely because disagreement on the Hill prevented 

Congress from altering the status quo and authorizing such 

regulation, how then can the very same deadlock be used to 

defeat Petitioners’ standing to challenge the Rule through 

which EPA effectuates its absurdist scheme? The Court 

cannot have it both ways. 

At bottom, bad decisions make bad law. In denying 

rehearing en banc, this Court has read Massachusetts to its 

illogical ends and it is American industry that will have to 

pay. That this Court did so is unsurprising, but certainly not 
23 

fated. Massachusetts does not compel this outcome for the 

PSD and Title V provisions. Had this Court interrogated its 

own assumptions and yielded not to Massachusetts’s telos but 

sound constitutional principles, it would have found that the 

matter properly belongs before Congress, not courts or 

agencies. As Schoolhouse Rock long ago explained: 

Ring one, Executive, 

Two is Legislative, that’s Congress. 

Ring three, Judiciary. 

See it’s kind of like my circus, circus.8

And what a circus it is. 

For these reasons, I respectfully dissent from the denial 

of rehearing en banc. 

 8

 “Three Ring Government,” Schoolhouse Rocks, available at 

http://www.schoolhouserock.tv/ThreeRing.html. 
KAVANAUGH, Circuit Judge, dissenting from the denial 

of rehearing en banc:

This case is plainly one of exceptional importance. A

decision in either direction will have massive real-world 

consequences. The U.S. Chamber of Commerce describes the 

EPA regulations at issue here as “the most burdensome, 

costly, far-reaching program ever adopted by a United States 

regulatory agency.” Petition for Rehearing En Banc at 1. On 

the other hand, EPA issued these regulations to help address 

global warming, a policy issue of major long-term

significance to the United States. Put simply, the economic 

and environmental policy stakes are very high.

Of course, our role is not to make the policy choices or to 

strike the balance between economic and environmental 

interests. That job is for Congress and the President when 

considering and enacting legislation, and then as appropriate 

for the Executive Branch – here, EPA, under the ultimate 

supervision of the President – when exercising its authority 

within statutory constraints. Our job as a court is more 

limited: to ensure that EPA has acted within the authority 

granted to it by Congress. In this case, I conclude that EPA 

has exceeded its statutory authority. I respectfully disagree 

with the panel opinion’s contrary conclusion, and given the 

overall importance of the case, I respectfully dissent from the 

denial of rehearing en banc.

I

A

This case concerns EPA’s implementation of the 

Prevention of Significant Deterioration provisions of the 

Clean Air Act. The Prevention of Significant Deterioration 

program – which is codified in Sections 7470 to 7479 of Title 

42 – is designed to maintain state and local compliance with
2

the National Ambient Air Quality Standards, known as the 

NAAQS. The NAAQS are currently established for six air 

pollutants: carbon monoxide, lead, nitrogen dioxide, ozone, 

particle pollution, and sulfur dioxide. As relevant here, the 

Prevention of Significant Deterioration statute requires 

stationary facilities that emit certain “air pollutants” to obtain 

permits before beginning new construction. See 42 U.S.C. 

§§ 7475(a)(1), 7479(1). To obtain a permit, the facility must 

undergo a lengthy, costly process to analyze the new 

construction’s impact on air quality and to try to demonstrate 

its compliance with the relevant emissions limits.

A central question in this case is how to construe the term

“air pollutant” for purposes of this statutory permitting 

requirement. In particular, the question is whether the term 

“air pollutant” here covers not just the NAAQS pollutants, 

which can cause breathing problems or other health issues, 

but also greenhouse gases such as carbon dioxide, which 

contribute to global warming. Under the broader 

interpretation of “air pollutant” that encompasses greenhouse 

gases, a far greater number of facilities would fall within the 

Prevention of Significant Deterioration program and have to 

obtain pre-construction permits. That in turn would impose 

significantly higher costs on businesses and individuals that 

are building new commercial or residential property.

In considering a different Clean Air Act program targeted 

at motor vehicle emissions, the Supreme Court said that the 

term “air pollutant” meant “all airborne compounds of 

whatever stripe,” which included greenhouse gases such as 

carbon dioxide. Massachusetts v. EPA, 549 U.S. 497, 529 

(2007). But all parties here, including EPA, agree that the 

Massachusetts v. EPA interpretation of the term “air 

pollutant” cannot control in this case, for purposes of this very 
3

different Clean Air Act program for stationary facilities. 

Rather, as the parties agree, we must look to the text and 

context of the Prevention of Significant Deterioration statute

to determine what “air pollutant” covers here. 

Looking at the relevant statutory text and context, there 

would initially appear to be two plausible interpretations of 

the term “air pollutant” for purposes of the Prevention of 

Significant Deterioration statute: (i) more broadly, an airborne 

compound that is deemed harmful and is regulated by EPA in 

any Clean Air Act program, which would include greenhouse 

gases such as carbon dioxide; or (ii) more narrowly, the six air 

pollutants that are regulated by EPA in setting and enforcing 

the NAAQS, which would cover carbon monoxide, lead, 

nitrogen dioxide, ozone, particle pollution, and sulfur dioxide,

but would not include greenhouse gases such as carbon 

dioxide. 

EPA chose the broader interpretation of “air pollutant,”

thereby greatly expanding the reach of the Prevention of 

Significant Deterioration statute. But that broader 

interpretation has a glaring problem, as EPA itself recognized.

In the context of the Prevention of Significant Deterioration 

statute, EPA’s broader interpretation would not mesh with 

other provisions of the statute and would lead to absurd 

results. That’s because the Prevention of Significant 

Deterioration statute requires pre-construction permits for 

facilities with the potential to emit more than 250 tons per 

year (or, for some facilities, 100 tons per year) of any covered 

pollutant. See 42 U.S.C. §§ 7475(a)(1), 7479(1). That would 

be a very low trigger for emissions of greenhouse gases

because greenhouse gases are emitted in far greater quantities 

than the NAAQS pollutants. As a result, the low trigger 

would mean a dramatically higher number of facilities would 
4

fall within the program and have to obtain pre-construction 

permits.

In an unusual twist, EPA openly acknowledged the 

unreasonableness – indeed, the absurdity – caused by its 

interpretation of the statute. If the Prevention of Significant 

Deterioration program were interpreted to require preconstruction permits based on emissions of greenhouse gases, 

EPA candidly stated that the result would be “so contrary to 

what Congress had in mind – and that in fact so undermines 

what Congress attempted to accomplish with the PSD 

requirements – that it should be avoided under the ‘absurd 

results’ doctrine.” 74 Fed. Reg. 55,292, 55,310 (Oct. 27, 

2009).

But faced with those absurd consequences from the 

broader interpretation of the statute, EPA surprisingly did not 

choose the seemingly obvious option of adopting the narrower 

and more sensible interpretation of the term “air pollutant” for 

the Prevention of Significant Deterioration statute – the 

interpretation limited to NAAQS air pollutants. Instead, EPA

plowed ahead with the broader interpretation. And then, to 

try to deal with the absurd repercussions of that interpretation

for the Prevention of Significant Deterioration statute, EPA

re-wrote the very specific 250-ton trigger in the permitting 

requirement of the statute, unilaterally raising that trigger for 

greenhouse gas emissions from 250 tons to 100,000 tons – a 

400-fold increase. See 75 Fed. Reg. 31,514 (June 3, 2010). 

EPA believed that re-writing the statute’s permitting-triggers 

provision in this way would reduce the number of facilities 

that would require pre-construction permits and thereby

“tailor” the absurdity – that is, alleviate some of the absurdity
5

caused by interpreting “air pollutant” to cover greenhouse 

gases.

1

This is a very strange way to interpret a statute. When an 

agency is faced with two initially plausible readings of a 

statutory term, but it turns out that one reading would cause 

absurd results, I am aware of no precedent that suggests the 

agency can still choose the absurd reading and then start rewriting other perfectly clear portions of the statute to try to 

make it all work out. And just recently, the Supreme Court 

reminded the Executive Branch and the lower courts that this 

is not the proper way to interpret a statute: Instead of 

“reading new words into the statute” to avoid absurd results, 

as the Government had urged in that case, the Court said that 

the statute should be interpreted so that “no absurdity arises in 

the first place.” Kloeckner v. Solis, No. 11-184, slip op. at 13 

(U.S. 2012).

Even limited to this case alone, the practical implications 

of accepting EPA’s approach are obviously major. And if this 

case stands as a precedent that influences other agency 

decisionmaking, the future consequences likewise could be 

significant: Agencies presumably could adopt absurd or 

otherwise unreasonable interpretations of statutory provisions 

and then edit other statutory provisions to mitigate the 

 1 At the same time, EPA reserved the right to ratchet the 

trigger all the way back down to 250 tons, thereby bringing more 

and more facilities under the program at EPA’s unilateral 

discretion. EPA’s assertion of such extraordinary discretionary 

power both exacerbates the separation of powers concerns in this 

case and underscores the implausibility of EPA’s statutory 

interpretation. Put simply, the statute cannot be read to grant 

discretion to EPA to raise or lower the permitting triggers as EPA 

sees fit.
6

unreasonableness. Allowing agencies to exercise that kind of 

statutory re-writing authority could significantly enhance the 

Executive Branch’s power at the expense of Congress’s and 

thereby alter the relative balance of powers in the 

administrative process. I would not go down that road.

B

In my view, the statutory issue here is reasonably 

straightforward. The Prevention of Significant Deterioration 

statute’s definition of “major emitting facility” subjects a 

facility to the permitting requirement based on the facility’s

emissions of “air pollutants.” See 42 U.S.C. §§ 7475(a)(1), 

7479(1). In the context of the Prevention of Significant 

Deterioration program as a whole, it seems evident that the 

term “air pollutant” refers to the NAAQS air pollutants.

To begin with, as explained above, interpreting “air 

pollutant” in this context to refer to the NAAQS air pollutants 

would avoid the absurd consequences that EPA’s broader 

interpretation creates – namely, the exponential increase in 

the number of facilities that would be required to obtain preconstruction permits. That single point alone provides 

dispositive support for the narrower, NAAQS-specific 

interpretation. See, e.g., Taniguchi v. Kan Pacific Saipan, 

Ltd., 132 S. Ct. 1997, 2004-05 (2012) (statutory context 

supports narrower rather than broader reading of statutory 

term).

Moreover, other provisions in the Prevention of 

Significant Deterioration statute likewise plainly use the term 

“air pollutant” to refer to the NAAQS air pollutants. The 

Prevention of Significant Deterioration program is codified in 

Sections 7470 to 7479 of Title 42. Of relevance here, Section 

7473 sets guidelines for areas designated as in attainment of 
7

the NAAQS and requires that the “concentration of any air 

pollutant” in those areas not exceed certain concentrations 

permitted by the NAAQS. 42 U.S.C. § 7473(b)(4). The term 

“air pollutant” in Section 7473(b)(4) necessarily refers to the 

NAAQS air pollutants. In addition, several other provisions 

in the Prevention of Significant Deterioration statute similarly 

refer to Section 7473(b)(4)’s maximum concentrations for 

NAAQS pollutants. Each of those references thus also

necessarily employs a NAAQS-specific use of the term “air 

pollutant.” See, e.g., 42 U.S.C. § 7473(c)(1) (listing 

exclusions from “the maximum allowable increases in 

ambient concentrations of an air pollutant”); § 7474(a)(B) 

(redesignations cannot cause “concentrations of any air 

pollutant” to exceed the maximum); see also § 7475(a)(3)(A) 

(facility may not cause air pollution in excess of “maximum 

allowable concentration for any pollutant”). 

So it’s clear that a variety of provisions in the Prevention 

of Significant Deterioration statute use “air pollutant” to refer 

to a NAAQS air pollutant. And we presume that, unless 

otherwise indicated, the term “air pollutant” is used the same 

way throughout the Prevention of Significant Deterioration 

statute – and here, we have no reason to conclude otherwise.

See IBP, Inc. v. Alvarez, 546 U.S. 21, 34 (2005) (“identical 

words used in different parts of the same statute are generally 

presumed to have the same meaning”).

By contrast, when Congress wanted, in the Prevention of 

Significant Deterioration statute, to refer to a broader set of 

pollutants than the NAAQS pollutants, it did so expressly. 

Thus, a facility that requires a pre-construction permit 

because of its emissions of NAAQS pollutants must employ 

the best available control technology for emissions not just of 

“air pollutants” but of “each pollutant subject to regulation 
8

under this chapter,” which – now that EPA has regulated 

greenhouse gases in other parts of the Clean Air Act – does

include greenhouse gases. 42 U.S.C. § 7475(a)(4). By its 

terms, Section 7475(a)(4) thus applies to greenhouse gases, 

not just the NAAQS. Importantly, however, Congress did not 

employ the language “each pollutant subject to regulation 

under this chapter” in the statutory provision setting forth 

which facilities must obtain a pre-construction permit, the 

provision at issue in this case. And the policy distinction 

drawn in Section 7475(a)(4) is rather intuitive: Congress 

designed the statute’s permitting requirement based on 

facilities’ NAAQS emissions, but, once those facilities are 

subject to the permitting requirement, they must also meet a 

range of other minimum environmental standards.2

The overall objectives of the Prevention of Significant 

Deterioration statute also suggest that “air pollutant” refers to

the NAAQS air pollutants for purposes of the permitting 

requirement. Importantly, the Prevention of Significant 

Deterioration statute applies only in areas that have met the 

NAAQS – that is, areas that do not have excessive emissions 

of the NAAQS air pollutants. If the purpose of this statute

were in part to address global warming by requiring preconstruction permits for facilities that emit greenhouse gases, 

as EPA’s reading suggests, why would the statute target the 

construction of facilities only in areas that are in compliance

with the NAAQS – and not elsewhere in the United States? 

 2 Section 7479(1) – the definition of “major emitting facility” 

– speaks of “any” air pollutant. But the word “any” just begs the 

question of what the term “air pollutant” covers in the Prevention of 

Significant Deterioration program. It’s either any air pollutant 

regulated under the Clean Air Act or any of the NAAQS air 

pollutants.
9

That would make little sense, which in turn further suggests 

that EPA has misread the statute.

Moreover, as its name indicates, the Prevention of 

Significant Deterioration statute is designed primarily to 

prevent “deterioration” of an attainment area’s air quality. 

The relevant air quality standards that define whether an area 

is in attainment are the NAAQS. In a statute expressly linked 

to the NAAQS and designed to ensure that air quality does 

not “deteriorate” with respect to the NAAQS, it is somewhat 

illogical to read the statute as requiring pre-construction 

permits simply because a facility may emit substances that 

will not affect attainment of the NAAQS. Under EPA’s 

approach, a facility could be covered by the permitting 

requirement even if it emits no NAAQS air pollutants at all. 

That, too, makes little sense and suggests that EPA has 

misread the statute.

A separate canon of interpretation further demonstrates

that EPA’s broad reading of the term “air pollutant” is at odds 

with Congress’s design. By requiring a vastly increased 

number of facilities to obtain pre-construction permits, EPA’s 

interpretation will impose enormous costs on tens of

thousands of American businesses, with corresponding effects 

on American jobs and workers; on many American

homeowners who move into new homes or plan other home 

construction projects; and on the U.S. economy more 

generally. Yet there is literally no indication in the text or 

legislative record that Members of Congress ever

contemplated – much less intended – such a dramatic 

expansion of the permitting requirement of the Prevention of 

Significant Deterioration statute. Courts do not lightly 

conclude that Congress intended such major consequences 

absent some indication that Congress meant to do so. See 
10

FDA v. Brown & Williamson Tobacco Corp., 529 U.S. 120, 

159-61 (2000). Here, as elsewhere, we should not presume 

that Congress hid an elephant in a mousehole.

For all of those reasons – the statutory text, the absurdity

principle, the statutory context as demonstrated by related 

statutory provisions, the overarching objectives of the statute, 

the major unintended consequences of a broader interpretation

– the Prevention of Significant Deterioration statute as a 

whole overwhelmingly indicates that the permitting 

requirement is based on emissions of the NAAQS air 

pollutants.

And just to reiterate, the simple and absolutely 

dispositive point in this case is the following: The broader 

interpretation of “air pollutant” adopted by EPA produces 

what even EPA itself admits are absurd consequences. When 

an agency is faced with two plausible readings of a statutory 

term, but one reading would cause absurd results, the agency 

cannot choose the absurd reading. Here, therefore, EPA was 

required to adopt the narrower and more sensible 

interpretation of “air pollutant,” the interpretation limited to

the NAAQS pollutants. As the Supreme Court has said, 

“interpretations of a statute which would produce absurd 

results are to be avoided if alternative interpretations 

consistent with the legislative purpose are available.” Griffin 

v. Oceanic Contractors, Inc., 458 U.S. 564, 575 (1982). Such

an “alternative interpretation[] consistent with the legislative 

purpose” is readily available here.

II

If that were the end of the analysis, I would not hesitate 

to conclude that EPA had adopted an impermissibly broad

reading of the term “air pollutant” for purposes of the 
11

permitting provision of the Prevention of Significant 

Deterioration statute. But before reaching that conclusion

definitively, we need to consider whether EPA’s approach 

was mandated by the Supreme Court’s decision in 

Massachusetts v. EPA, 549 U.S. 497 (2007). In that case, the 

Supreme Court considered the general statutory term “air 

pollutant” as applied to a different aspect of the Clean Air Act 

– the motor vehicle emissions program. The Court there 

interpreted “air pollutant” very broadly to mean “all airborne 

compounds of whatever stripe,” including greenhouse gases. 

Id. at 529.

Does Massachusetts v. EPA dictate EPA’s broader 

interpretation of “air pollutant” in the different context of the 

Prevention of Significant Deterioration statute? The panel 

opinion seemed to think so; its conclusion appears to have 

been heavily if not dispositively influenced by Massachusetts 

v. EPA. See, e.g., Coalition for Responsible Regulation, Inc. 

v. EPA, 684 F.3d 102, 134, 136 (D.C. Cir. 2012). In my view,

however, the holding in Massachusetts v. EPA does not 

control the result in this case. Indeed, as explained more fully 

below, even EPA has concluded that Massachusetts v. EPA

does not control here. The decision in Massachusetts v. EPA

concerned the motor vehicle emissions program, a point the 

Supreme Court expressly noted many times in its opinion. 

The case did not purport to say that every other use of the 

term “air pollutant” throughout the sprawling and multifaceted Clean Air Act necessarily includes greenhouse gases. 

Each individual Clean Air Act program must be considered in 

context.3

 3 As an analogy, take the familiar example of “no vehicles in 

the park.” Assume that a court has decided that the term “vehicles” 

generally includes bicycles, and that no bicycles are allowed in the 
12

Importantly, in Massachusetts v. EPA, the Supreme Court 

explicitly relied on the fact that the Clean Air Act’s

“capacious definition of ‘air pollutant,’” did not appear 

“counterintuitive” or produce “extreme” consequences in the 

context of motor vehicle emissions. 549 U.S. at 531-32. But, 

as explained above, EPA’s capacious definition of “air 

pollutant” is counterintuitive and does produce extreme 

consequences in the context of the Prevention of Significant 

Deterioration statute, as EPA itself acknowledges. Moreover, 

in this case, an alternative and sensible interpretation of the 

term “air pollutant” is readily discernible from the text, 

context, and structure of the Prevention of Significant 

Deterioration statute as a whole – namely, the NAAQSspecific interpretation.

To be sure, as noted earlier, the same words used in 

different parts of an Act are often construed to have the same 

meaning. See IBP, Inc. v. Alvarez, 546 U.S. 21, 34 (2005). If 

that were an inflexible command, the Massachusetts v. EPA

interpretation of “air pollutant” would certainly control here

 

park. Next assume that another park regulation states that “all park 

service vehicles must have reinforced gas tanks.” In that latter 

regulation, context tells us that the term “vehicles” obviously does 

not include bicycles. Bicycles are still vehicles in the abstract, but 

the gas-tank regulation logically applies only to a specific subset of 

vehicles (namely, motor vehicles).

So it is with “air pollutant” as used in different parts of the 

Clean Air Act. Massachusetts v. EPA held that the term “air 

pollutant” generally includes greenhouse gases. But that does not 

mean that the term “air pollutant” can never be used in a narrower 

sense. Greenhouse gases may qualify as “air pollutants” in the 

abstract, but context tells us that the Prevention of Significant 

Deterioration program uses the term “air pollutant” to refer only to 

a subset of all air pollutants (namely, the NAAQS pollutants).
13

and throughout the entire Clean Air Act. But as the Supreme 

Court recently reminded us – in the context of interpreting the 

Clean Air Act – “the natural presumption that identical words 

used in different parts of the same act are intended to have the 

same meaning is not rigid and readily yields whenever there is 

such variation in the connection in which the words are used 

as reasonably to warrant the conclusion that they were 

employed in different parts of the act with different intent.” 

Environmental Defense v. Duke Energy Corp., 549 U.S. 561, 

574 (2007) (internal quotation marks and ellipsis omitted). 

As instructed by the Supreme Court, we must interpret 

statutory terms based on their context and in light of the 

statute as a whole, even if that approach on some occasions

means that the same term applies differently in different parts 

of a statute. See, e.g., General Dynamics Land Systems, Inc. 

v. Cline, 540 U.S. 581, 596-97 (2004) (term “age” has 

different meanings within Age Discrimination in Employment 

Act); United States v. Cleveland Indians Baseball Co., 532 

U.S. 200, 212-13 (2001) (term “wages paid” has different 

meanings within Social Security Act Amendments of 1939); 

Robinson v. Shell Oil Co., 519 U.S. 337, 343-44 (1997) (term 

“employee” has different meanings within Title VII).

The Supreme Court’s application of that interpretive

principle in Environmental Defense v. Duke Energy – a

decision issued on the same day as Massachusetts v. EPA – is 

illuminating. There, the Supreme Court confronted the Clean 

Air Act’s definition of a stationary source “modification.” 

See 549 U.S. at 567-68. That term was relevant to both the 

New Source Performance Standards program and the 

Prevention of Significant Deterioration program. The Court 

ruled that EPA could interpret the term “modification”

differently for each of those two Clean Air Act programs, 

even though “the terms share a common statutory definition.” 
14

Id. at 574. In so holding, the Court analyzed the two 

programs’ different regulatory goals, noting that a “given 

term in the same statute may take on distinct characters from 

association with distinct statutory objects calling for different 

implementation strategies.” Id.

The Supreme Court’s interpretive approach in 

Environmental Defense v. Duke Energy – which recognizes 

that the meaning of a statutory term in the Clean Air Act may 

vary based on the particular program at issue – shows that the 

Massachusetts v. EPA interpretation of “air pollutant” in the 

context of the motor vehicle emissions program does not 

necessarily require the same interpretation of “air pollutant” 

in the context of the Prevention of Significant Deterioration 

program. In Massachusetts v. EPA, the Supreme Court 

emphasized that the regulation of greenhouse gases in the 

motor vehicle emissions program would not be 

“counterintuitive” and would not lead to any “extreme 

measures.” 549 U.S. at 531. Greenhouse gas standards 

would simply be added to the other regulations already 

applicable to manufacturers of new motor vehicles, and any 

such standards would take into account both cost and 

technological feasibility. See 42 U.S.C. § 7521(a). By

contrast, the regulation of greenhouse gases in the Prevention 

of Significant Deterioration program would be both 

counterintuitive and extreme. Tens of thousands of 

businesses and homeowners would be swept into the Clean 

Air Act’s purview for the first time and hit with permitting

costs averaging $60,000, not to mention the additional costs 

of trying to construct and maintain the facility in compliance 

with the relevant emissions limits and technological 

standards. See 75 Fed. Reg. 31,514, 31,556 (June 3, 2010). 

In addition, the costs associated with a vastly expanded 

permitting requirement would deter numerous projects from 
15

even starting in the first place. The major differences 

between the motor vehicle emissions program and the 

Prevention of Significant Deterioration program thus neatly

fit the Environmental Defense v. Duke Energy paradigm of 

“distinct statutory objects calling for different implementation 

strategies.”

In reaching that conclusion, it bears mention that the 

Clean Air Act is a very complicated statute encompassing

several distinct environmental programs. It is no surprise,

then, that the motor vehicle emissions program and the 

Prevention of Significant Deterioration program are not the 

only parts of the Act to employ a term like “air pollutant” in a 

context-dependent way. For example, the visibility program 

applies to facilities based on their emissions of “any 

pollutant.” 42 U.S.C. § 7491(g)(7). In the context of that 

program, EPA has interpreted the term “any pollutant” to 

mean “any visibility-impairing pollutant,” which obviously 

does not include greenhouse gases. 40 C.F.R. pt. 51, App. Y, 

§ II.A. Similarly, the nonattainment program applies to areas 

that have been designated as nonattainment “for any air 

pollutant.” 42 U.S.C. § 7501(2). In the context of that 

program, the term “air pollutant” is logically limited to the 

NAAQS air pollutants, which are the only pollutants for 

which an area can be designated as nonattainment. Id. 

§ 7407(d)(1)(A). All of that simply underscores that a court 

should exercise caution before reflexively importing the 

interpretations applicable to one Clean Air Act program into a 

distinct Clean Air Act program.

Any lingering doubt that Massachusetts v. EPA does not 

control here is dispelled when we recall that EPA itself has 

rejected Massachusetts v. EPA’s interpretation of “air 

pollutant” for the Prevention of Significant Deterioration 
16

statute. The Court in Massachusetts v. EPA said that “air 

pollutant” meant “all airborne compounds of whatever stripe.” 

549 U.S. at 529. EPA has acknowledged, however, that such 

a broad definition cannot possibly extend to the use of the 

term “air pollutant” in the Prevention of Significant 

Deterioration statute. EPA understood that it would be absurd 

to require pre-construction permits because of emissions of 

any airborne compound, including emissions of airborne 

compounds that have not been deemed harmful and regulated 

under the Clean Air Act. To avoid rendering the Prevention 

of Significant Deterioration statute an absurdity, EPA 

construed “air pollutant” to mean certain air pollutants – in

particular, “any regulated air pollutant.”

The critical point for present purposes – and it really is a 

critical point in thinking about the significance of 

Massachusetts v. EPA to the present case – is that EPA itself 

recognized that the Massachusetts v. EPA definition of “air 

pollutant” cannot and does not control how to interpret “air 

pollutant” in the Prevention of Significant Deterioration 

context. As it tries to justify its broad interpretation of the 

Prevention of Significant Deterioration statute, EPA cannot 

simultaneously latch on to Massachusetts v. EPA and reject 

Massachusetts v. EPA.

If Massachusetts v. EPA does not control here – and even 

EPA admits that it does not – then we are back where we 

started. EPA was faced with two initially plausible

interpretations of “air pollutant” for purposes of the

permitting requirement of the Prevention of Significant 

Deterioration statute. One interpretation created patent 

absurdities and made little sense given the other statutory 

provisions. The other interpretation fit comfortably and 

sensibly within the statutory text and context. EPA 
17

nonetheless chose the first option. In my view, EPA’s reading 

of the statute was impermissible. An agency cannot adopt an 

admittedly absurd interpretation and discard an eminently

sensible one.

Given all of this, the case seems reasonably 

straightforward. So how did the panel opinion reach the 

opposite conclusion? I respectfully have three main points of 

disagreement. First, as I read it, the panel opinion was 

decisively influenced by Massachusetts v. EPA’s 

interpretation of “air pollutant” in the context of the motor 

vehicle emissions program. But in light of the material 

differences between the motor vehicle emissions program and 

the Prevention of Significant Deterioration program, the 

Massachusetts v. EPA interpretation cannot control here, as 

even EPA acknowledges. Second, the panel opinion 

attempted to buttress its choice of a broad interpretation of the 

term “air pollutant” by pointing to Section 7475(a)(4), the 

provision in the Prevention of Significant Deterioration 

program requiring covered facilities to use the best available 

control technology. But as explained above, Section 

7475(a)(4) actually cuts the other way because it specifically 

refers to “each pollutant subject to regulation under this 

chapter,” which now does include greenhouse gases –

whereas, by contrast, other statutory provisions in the 

Prevention of Significant Deterioration program clearly 

employ a NAAQS-specific interpretation of the unadorned 

term “air pollutant.” Third, the panel gave insufficient weight

to the most critical point in this case, the absurd consequences 

of EPA’s broad interpretation. This was a mistake because 

the ultimate clincher in this case is one simple point: EPA 

chose an admittedly absurd reading over a perfectly natural 

reading of the relevant statutory text. An agency cannot do 

that.
18

III

In finding EPA’s statutory interpretation legally 

impermissible, I do not in any way want to diminish EPA’s 

vital policy objectives. EPA’s regulations for the Prevention 

of Significant Deterioration statute may well be a good idea as 

a matter of policy. The task of dealing with global warming 

is urgent and important. But as in so many cases, the question 

here is: Who Decides? The short answer is that Congress 

(with the President) sets the policy through statutes, agencies 

implement that policy within statutory limits, and courts in 

justiciable cases ensure that agencies stay within the statutory 

limits set by Congress. A court’s assessment of an agency’s 

compliance with statutory limits does not depend on whether 

the agency’s policy is good or whether the agency’s intentions 

are laudatory. Even when that is true, we must enforce the 

statutory limits. See Hamdan v. United States, 696 F.3d 1238 

(D.C. Cir. 2012) (ruling that Executive Branch exceeded 

statutory authority in wartime prosecution of al Qaeda 

member).

In cases like this one, the bedrock underpinnings of our 

system of separation of powers are at stake. To be sure, 

courts must be wary of undue interference with an agency’s 

action implementing its statutory responsibilities. See 

American Radio Relay League, Inc. v. FCC, 524 F.3d 227 

(D.C. Cir. 2008) (separate opinion of Kavanaugh, J.); see also 

Desert Citizens Against Pollution v. EPA, 699 F.3d 524 (D.C. 

Cir. 2012); National Environmental Development 

Association’s Clean Air Project v. EPA, 686 F.3d 803 (D.C. 

Cir. 2012); American Petroleum Institute v. EPA, 684 F.3d 

1342 (D.C. Cir. 2012); ATK Launch Systems, Inc. v. EPA, 669 

F.3d 330 (D.C. Cir. 2012); Natural Resources Defense 

Council v. EPA, 661 F.3d 662 (D.C. Cir. 2011); Medical 
19

Waste Institute & Energy Recovery Council v. EPA, 645 F.3d 

420 (D.C. Cir. 2011). To take one salient and important 

example, the statutory scheme gives EPA significant 

discretion in setting the NAAQS for the NAAQS air 

pollutants – a discretion the courts must respect.

But at the same time, undue deference or abdication to an 

agency carries its own systemic costs. If a court mistakenly 

allows an agency’s transgression of statutory limits, then we 

green-light a significant shift of power from the Legislative

Branch to the Executive Branch. The Framers of the 

Constitution did not grant the Executive Branch the authority 

to set economic and social policy as it sees fit. Rather, the 

Framers gave Congress, along with the President, that 

legislative role (subject to constitutional limits), and they 

assigned the Executive Branch the executive power to issue 

rules and enforce the law within the limits set by Congress.

4

It is true that the legislative process can be cumbersome 

and frustrating, and the Executive Branch often is wellintentioned in wanting to address pressing policy concerns 

quickly, before the sometimes glacial congressional 

machinery can be stirred to action.5

 The legislative process 

 4 In protecting national security, the Executive has some 

Article II authority to act in certain circumstances in the Nation’s 

defense even without specific congressional authorization. This is 

known as Youngstown category two. See Youngstown Sheet & 

Tube Co. v. Sawyer, 343 U.S. 579, 637 (1952) (Jackson, J., 

concurring). There is no general Youngstown category two

authority in the domestic social and economic realms, where the 

Executive must have statutory authority in order to act.

5 In 2009, the House of Representatives passed a global 

warming bill that was supported by the President. But the Senate 

did not pass it. In the early 2000s, Senators McCain and Lieberman 
20

can be slow because the Constitution makes it far harder to 

enact legislation than to block it: Under the Constitution, 

three different entities must agree in order to enact legislation

– the House, the Senate, and the President (or two-thirds of 

both the House and the Senate to override a President’s veto). 

But the Framers knew the legislative process would be 

laborious. They designed it that way. The time and difficulty 

of enacting new legislation has never justified an agency’s

contravention of statutory limits. The Framers specifically 

contemplated, moreover, that there would be situations where 

the Executive Branch confronts a pressing need that it does 

not have current authority to address. In those circumstances, 

the Constitution’s Recommendations Clause provides that the 

President may “recommend” to Congress “such Measures as 

he shall judge necessary and expedient.” U.S. CONST. art. II, 

§ 3.

Importantly, the separation of powers and checks and 

balances of our system are designed not just to ensure that the 

Branches operate within the proper spheres of their authority, 

but also to protect individual liberty. As the Supreme Court 

has explained many times, “while a government of opposite 

and rival interests may sometimes inhibit the smooth 

functioning of administration, the Framers recognized that, in 

the long term, structural protections against abuse of power 

were critical to preserving liberty. . . . The failures of . . . 

regulation may be a pressing national problem, but a judiciary 

that licensed extraconstitutional government with each issue 

of comparable gravity would, in the long run, be far worse.” 

Free Enterprise Fund v. Public Company Accounting 

 

sought to pass global warming legislation, but no law was 

ultimately enacted. Numerous other bills have been introduced 

over the years, and various legislative efforts are ongoing.
21

Oversight Board, 130 S. Ct. 3138, 3157 (2010) (internal 

quotation marks, alterations, and citations omitted).

As a court, it is not our job to make the policy choices 

and set the statutory boundaries, but it is emphatically our job 

to carefully but firmly enforce the statutory boundaries. That 

bedrock separation of powers principle accounts for my 

concern about this case. Here, as I see it, EPA went well 

beyond what Congress authorized for the Prevention of 

Significant Deterioration statute. I respectfully disagree with 

the panel’s resolution of this issue, and given the overall 

importance of the case, I respectfully dissent from the denial 

of rehearing en banc.