FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

WILDEARTH GUARDIANS, MIDWEST

ENVIRONMENTAL DEFENSE CENTER,

and SIERRA CLUB,

Plaintiffs-Appellants,

v.

GINA MCCARTHY, in her official

capacity as Administrator of the

Environmental Protection Agency,

Defendant-Appellee.

No. 12-16797

D.C. No.

4:11-cv-05651-

YGR

OPINION

Appeal from the United States District Court

for the Northern District of California

Yvonne Gonzalez Rogers, District Judge, Presiding

Argued and Submitted

October 10, 2014—San Francisco, California

Filed December 1, 2014

Before: William C. Canby, Jr., William A. Fletcher,

and Paul J. Watford, Circuit Judges.

Opinion by Judge Watford
2 WILDEARTH GUARDIANS V. MCCARTHY

SUMMARY*

Environmental Law

The panel affirmed the district court’s dismissal for lack

of subject matter jurisdiction of plaintiff environmental

groups’ Clear Air Act citizen-suit action seeking to require

the Environmental Protection Agency’s Administrator to

issue revised regulations governing ozone pollution.

The Clean Air Act’s citizen-suit provision, 42 U.S.C.

§ 7604, authorizes suits against the EPA’s Administrator

only for actions where there is an alleged failure by the

Administrator to perform an act or duty which is not

discretionary with the Administrator. In 1977, Congress

added a new program to the Clean Air Act, known as the

Prevention of Significant Deterioration (PSD) program, to

prevent air quality from significantly deteriorating in areas

that already had relatively clean air. Section 166(a) of the

Clean Air Act required the EPA to issue regulations 

implementing the PSD program, and plaintiffs alleged that

the Administrator had a nondiscretionarydutyto issue revised

ozone regulations under § 166(a).

The panel held that given § 166(a)’s ambiguity, the

existence of a nondiscretionary duty to promulgate revised

PSD regulations for ozone was not clear cut or readily

ascertainable from the statute. The panel concluded that this

was enough to preclude plaintiffs’ reliance on § 7604(a)(2)

as the jurisdictional basis for their suit.

* This summary constitutes no part of the opinion of the court. It has

been prepared by court staff for the convenience of the reader.
WILDEARTH GUARDIANS V. MCCARTHY 3

COUNSEL

David Bender (argued) and Christa Westerberg, McGillivray,

Westerberg & Bender, Madison, Wisconsin; Robert Ukeiley,

Berea, Kentucky; Kristin Henry, Sierra Club, San Francisco,

California; James Jay Tutchton, WildEarth Guardians,

Centennial, Colorado, for Plaintiffs-Appellants.

Robert Lundman (argued), Ignacia Moreno, Assistant

Attorney General, Eileen McDonough, and David Gunter,

United States Department of Justice, Environment & Natural

Resources Division, Washington, D.C.; Brian Doster and

Melina Williams, Office of General Counsel, Environmental

Protection Agency, for Defendant-Appellee.

OPINION

WATFORD, Circuit Judge:

Plaintiffs WildEarth Guardians, Midwest Environmental

Defense Center, and Sierra Club are organizations dedicated

to environmental conservation. They believe the

Environmental Protection Agency (EPA) has been derelict in

its duty to protect the nation’s air from ground-level ozone

pollution. They sued the EPA’s Administrator in federal

district court, seeking an order that would force the

Administrator to issue revised regulations governing ozone

pollution.

Plaintiffs invoked the Clean Air Act’s citizen-suit

provision, 42 U.S.C. § 7604, as the sole basis for subject

matter jurisdiction. That provision authorizes suits against

the Administrator, but only for actions “where there is alleged
4 WILDEARTH GUARDIANS V. MCCARTHY

a failure of the Administrator to perform any act or duty

under this chapter which is not discretionary with the

Administrator.” § 7604(a)(2) (emphasis added). Plaintiffs

contend the Administrator has a nondiscretionary duty to

issue revised ozone regulations under § 166(a) of the Clean

Air Act, 42 U.S.C. § 7476(a). The district court held that the

statute permits, but does not require, the Administrator to

issue such regulations and therefore dismissed plaintiffs’

claim for lack of subject matter jurisdiction. To facilitate

immediate appeal, the court granted plaintiffs’ request to

enter final judgment on that claim under Federal Rule of Civil

Procedure 54(b).

The only issue on appeal is whether plaintiffs have

adequately alleged the violation of a nondiscretionary duty. 

Before we discuss the parties’ competing interpretations of

§ 166(a), a brief summary of the relevant regulatory scheme

is necessary.

When Congress enacted the Clean Air Act Amendments

of 1970, it required EPA to identify pollutants that “cause or

contribute to air pollution which may reasonably be

anticipated to endanger public health or welfare.” 42 U.S.C.

§ 7408(a)(1)(A). For each such pollutant, Congress required

EPA to issue national ambient air quality standards

(NAAQS). § 7409(a)(1)(A). To oversimplify a bit, NAAQS

set limits on the permissible concentrations of regulated

pollutants in the ambient air.

In 1971, EPA issued NAAQS for six pollutants:

particulate matter, sulfur dioxide, photochemical oxidants,

hydrocarbons, carbon monoxide, and nitrogen dioxide. 

36 Fed. Reg. 8186, 8186 (Apr. 30, 1971). The term

“photochemical oxidants” includes ozone, and in 1979 EPA
WILDEARTH GUARDIANS V. MCCARTHY 5

formally changed the chemical designation for the relevant

NAAQS to “ozone.” 44 Fed. Reg. 8202, 8202 (Feb. 8, 1979). 

For our purposes, “photochemical oxidants” and “ozone”

refer to the same thing.

On August 7, 1977, Congress added a new program to the

Clean Air Act, known as the Prevention of Significant

Deterioration (PSD) program. Clean Air Act Amendments of

1977, Pub. L. No. 95–95, 91 Stat. 685. As its name implies,

the PSD program is designed to prevent air quality from

significantlydeteriorating in areas that alreadyhave relatively

clean air. The program thus applies to “attainment” areas,

meaning areas that meet the NAAQS for a given pollutant,

and “unclassifiable” areas, meaning areas for which

insufficient data exists to determine whether the NAAQS for

a given pollutant have or have not been met. 42 U.S.C.

§ 7471; Alaska Dep’t of Envtl. Conservation v. EPA, 540 U.S.

461, 470–71 (2004).

As part of the newly enacted PSD program, Congress

added § 166 of the Clean Air Act, the statute at issue here. 

Subsection (a) requires EPA to issue regulations

implementing the PSD program. It provides in full:

(a) Hydrocarbons, carbon monoxide,

photochemical oxidants, and nitrogen oxides

In the case of the pollutants hydrocarbons,

carbon monoxide, photochemical oxidants,

and nitrogen oxides, the Administrator shall

conduct a study and not later than two years

after August 7, 1977, promulgate regulations

to prevent the significant deterioration of air

qualitywhich would result from the emissions
6 WILDEARTH GUARDIANS V. MCCARTHY

of such pollutants. In the case of pollutants

for which national ambient air quality

standards are promulgated after August 7,

1977, he shall promulgate such regulations

not more than 2 years after the date of

promulgation of such standards.

42 U.S.C. § 7476(a).

Both the first and second sentences of this provision

unquestionably impose nondiscretionary duties on the

Administrator. The first sentence required the Administrator

to promulgate PSD regulations for the four listed pollutants

no later than August 7, 1979. The parties agree that this duty

has long since been discharged. The focus of this appeal is

therefore on the duty imposed by the second sentence. That

sentence, too, requires the Administrator to promulgate PSD

regulations, but the precise scope of the nondiscretionaryduty

it imposes depends on how broadly or narrowly one interprets

the sentence.

We’ll begin with the narrow interpretation, which is the

one EPA favors. Read together, the first and second

sentences of § 166(a) could be construed as referring to two

mutually exclusive sets of pollutants: pollutants for which

NAAQS had already been promulgated as of August 7, 1977

(first sentence), and pollutants for which NAAQS would not

be promulgated until sometime later (second sentence). 

Under that reading, the second sentence would impose a

nondiscretionary duty, but a one-time duty of limited scope:

to promulgate PSD regulations within two years after

NAAQS are first issued for a newly regulated pollutant. 

Since ozone is one of the alreadyregulated pollutants covered
WILDEARTH GUARDIANS V. MCCARTHY 7

by the first sentence, EPA argues, the mandatory duty

imposed by the second sentence simply doesn’t apply here.

Plaintiffs, of course, urge us to reject that reading. They

contend the second sentence should be read more broadly to

cover all pollutants. Read in that fashion, the second

sentence would impose a nondiscretionarydutyto promulgate

PSD regulations not only when NAAQS are first issued for a

newly regulated pollutant, but also when NAAQS are revised

for any pollutant, including the four mentioned in the first

sentence. Because EPA revised the NAAQS for ozone on

March 27, 2008, plaintiffs argue, the agency had a

nondiscretionary duty to promulgate revised PSD regulations

for ozone within two years of that date. It is undisputed that

EPA did not do so, and in fact still has not done so.

If our task were to decide which of these two readings of

the statute is correct, this might be a hard case, since both

appear plausible. On the one hand, the narrow reading is

plausible given the parallel structure of the first and second

sentences. The first sentence begins, “In the case of the [four

named pollutants]”; the second begins, “In the case of

pollutants for which [NAAQS] are promulgated after August

7, 1977. . . .” The repeated use of the phrase “In the case of”

suggests that the drafters intended the first sentence to

address one set of circumstances and the second sentence to

address another. That inference is strengthened by the fact

that, as of August 7, 1977, the only pollutants then subject to

NAAQS for which PSD regulations would be required were

the four listed in the first sentence. (There were two

additional pollutants for which NAAQS had already been

issued—particulate matter and sulfur dioxide—but EPA

didn’t need to promulgate PSD regulations for them because

Congress itself had established the initial PSD requirements
8 WILDEARTH GUARDIANS V. MCCARTHY

in a separate statutory provision. See 42 U.S.C. § 7473.) It’s

thus easy to see why those drafting the statute in 1977 might

have used the phrase “pollutants for which [NAAQS] are

promulgated after August 7, 1977” to distinguish the set of

as-yet-unregulated pollutants covered by the second sentence

from the distinct set of already regulated pollutants covered

by the first. While the text might have been clearer had the

second sentence referred to “other pollutants not covered by

the first sentence,” or “pollutants for which NAAQS are first

promulgated after August 7, 1977,” the drafters could have

understood the language they chose as already drawing that

distinction.

On the other hand, plaintiffs’ broad reading of the second

sentence—as encompassing all pollutants and imposing a

mandatory duty to revise the PSD regulations each time the

NAAQS are revised—is plausible as well. As plaintiffs point

out, it would have been sensible for Congress to conclude that

whenever the NAAQS for a given pollutant are revised, the

corresponding PSD regulations should be revised too, since

new information that justifies revisions to the NAAQS would

likely justify revisions to the PSD requirements. (EPA has

historically calculated PSD requirements by calibrating them

to the NAAQS governing each pollutant. See 75 Fed. Reg.

64,864-01, 64,869 (Oct. 20, 2010).) But even if Congress

held that view, it doesn’t strike us as irrational or absurd, as

plaintiffs suggest, for Congress to have created a regulatory

scheme predicated on the narrow reading of § 166(a). 

Congress could have been content to kick-start the PSD

program by mandating EPA’s promulgation of initial PSD

regulations, but then have left to the agency’s discretion the

responsibility for making whatever revisions to those

regulations might be warranted when the corresponding

NAAQS were revised.
WILDEARTH GUARDIANS V. MCCARTHY 9

In the end, we don’t have to decide which of these

conflicting interpretations of § 166(a) is correct, because our

cases have adopted what amounts to a clear statement rule in

this context. When a plaintiff sues the EPA Administrator for

failure “to perform any act or duty under this chapter which

is not discretionary with the Administrator,” 42 U.S.C.

§ 7604(a)(2), we have held that the nondiscretionary nature

of the duty must be clear-cut—that is, readily ascertainable

from the statute allegedly giving rise to the duty. Our

Children’s Earth Found. v. EPA, 527 F.3d 842, 851 (9th Cir.

2008) (interpreting the Clean Water Act’s similar citizen-suit

provision); see also Farmers Union Cent. Exch., Inc. v.

Thomas, 881 F.2d 757, 760 (9th Cir. 1989). We must be able

to identify a “specific, unequivocal command” from the text

of the statute at issue using traditional tools of statutory

interpretation; it’s not enough that such a command could be

teased out “from an amalgamation of disputed statutory

provisions and legislative history coupled with the EPA’s

own earlier interpretation.” Our Children’s Earth, 527 F.3d

at 851 (internal quotation marks omitted).

Given § 166(a)’s ambiguity, we cannot say that the

existence of a nondiscretionary duty to promulgate revised

PSD regulations for ozone is clear-cut or readily ascertainable

from the statute. That is enough to preclude plaintiffs’

reliance on § 7604(a)(2) as the jurisdictional basis for their

suit. The district court therefore correctly dismissed

plaintiffs’ claim under the Clean Air Act’s citizen-suit

provision for lack of subject matter jurisdiction.

AFFIRMED.