                FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


NATURAL RESOURCES DEFENSE             No. 18-15380
COUNCIL, INC.; SIERRA CLUB;
CONSUMER FEDERATION OF                  D.C. Nos.
AMERICA; TEXAS RATEPAYERS’          3:17-cv-03404-VC
ORGANIZATION TO SAVE                3:17-cv-03406-VC
ENERGY; PEOPLE OF THE STATE
OF CALIFORNIA, BY AND
THROUGH ATTORNEY GENERAL
XAVIER BECERRA; CALIFORNIA
STATE ENERGY RESOURCES
CONSERVATION AND
DEVELOPMENT COMMISSION;
STATE OF MARYLAND; STATE OF
WASHINGTON; STATE OF MAINE;
COMMONWEALTH OF
MASSACHUSETTS; STATE OF
VERMONT; STATE OF
CONNECTICUT; COMMONWEALTH
OF PENNSYLVANIA; DISTRICT OF
COLUMBIA; STATE OF ILLINOIS;
STATE OF NEW YORK; STATE OF
OREGON; CITY OF NEW YORK;
STATE OF MINNESOTA,
            Plaintiffs-Appellees,

               v.
2                   NRDC V. PERRY


JAMES R. PERRY, in his official
capacity as Secretary of Energy;
U.S. DEPARTMENT OF ENERGY,
          Defendants-Appellants,

              and

AIR-CONDITIONING, HEATING, &
REFRIGERATION INSTITUTE,
         Intervenor-Defendant.


NATURAL RESOURCES DEFENSE             No. 18-15475
COUNCIL, INC.; SIERRA CLUB;
CONSUMER FEDERATION OF                  D.C. Nos.
AMERICA; TEXAS RATEPAYERS’          3:17-cv-03404-VC
ORGANIZATION TO SAVE                3:17-cv-03406-VC
ENERGY; PEOPLE OF THE STATE
OF CALIFORNIA, BY AND
THROUGH ATTORNEY GENERAL               OPINION
XAVIER BECERRA; CALIFORNIA
STATE ENERGY RESOURCES
CONSERVATION AND
DEVELOPMENT COMMISSION;
STATE OF MARYLAND; STATE OF
WASHINGTON; STATE OF MAINE;
COMMONWEALTH OF
MASSACHUSETTS; STATE OF
VERMONT; STATE OF
CONNECTICUT; COMMONWEALTH
OF PENNSYLVANIA; DISTRICT OF
COLUMBIA; STATE OF ILLINOIS;
STATE OF NEW YORK; STATE OF
                         NRDC V. PERRY                               3


 OREGON; CITY OF NEW YORK;
 STATE OF MINNESOTA,
            Plaintiffs-Appellees,

                    v.

 JAMES R. PERRY, in his official
 capacity as Secretary of Energy;
 U.S. DEPARTMENT OF ENERGY,
                       Defendants,

                   and

 AIR-CONDITIONING, HEATING, &
 REFRIGERATION INSTITUTE,
  Intervenor-Defendant-Appellant.

        Appeals from the United States District Court
           for the Northern District of California
         Vince Chhabria, District Judge, Presiding

         Argued and Submitted November 14, 2018
                 San Francisco, California

                     Filed October 10, 2019

 Before: Mary M. Schroeder and Paul J. Watford, Circuit
       Judges, and David A. Ezra, * District Judge.

                   Opinion by Judge Watford


    *
      The Honorable David A. Ezra, United States District Judge for the
District of Hawaii, sitting by designation.
4                        NRDC V. PERRY

                          SUMMARY **



            Department of Energy / Regulations

   The panel affirmed the district court’s order directing the
U.S. Department of Energy (“DOE”) to publish four energy-
conservation standards in the Federal Register.

    The district court agreed with the plaintiffs’ contention
that a DOE regulation known as the “error-correction rule,”
10 C.F.R. § 430.5, imposed upon DOE a non-discretionary
duty to publish the standards in the Federal Register, and its
refusal to do so violated the rule.

   The plaintiffs are a group of States and municipalities as
well as several environmental and consumer organizations.
They brought suit against DOE under the Energy Policy and
Conservation Act (EPCA)’s citizen-suit provision.

    The panel rejected DOE’s challenges to the district
court’s assertion of jurisdiction under 42 U.S.C.
§ 6305(a)(2). The panel held that DOE relinquished
whatever discretion it might have had to withhold
publication of the rules at issue when it adopted the error-
correction rule. The panel further held that by delaying
publication of the four rules beyond the period permitted
under the error-correction rule, DOE violated the non-
discretionary duty imposed by its own regulation. The panel
also held that plaintiffs were not precluded from bringing the
action under 42 U.S.C. § 6305(a)(2). The panel held that
    **
       This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
                      NRDC V. PERRY                        5

§ 6305(a)(2) provided the necessary clear waiver of
sovereign immunity from citizen suits predicated on a non-
discretionary duty imposed either by statute or regulation.

    The panel held that the plaintiffs properly invoked
EPCA’s citizen-suit provision to challenge DOE’s failure to
perform is non-discretionary duty to submit the four rules at
issue for publication in the Federal Register.


                        COUNSEL

H. Thomas Byron III (argued) and Mark B. Stern, Appellate
Staff; Alex G. Tse, Acting United States Attorney; Civil
Division, United States Department of Justice, Washington,
D.C.; for Defendants-Appellants.

Ian Fein (argued), Natural Resources Defense Council, San
Francisco, California; Aaron Colangelo, Natural Resources
Defense Council, Washington, D.C.; Daniel Carpenter-
Gold, Natural Resources Defense Council, New York, New
York; for Plaintiff-Appellee Natural Resources Defense
Council, Inc.

Timothy D. Ballo, Earthjustice, Washington, D.C., for
Plaintiffs-Appellees Sierra Club, Consumer Federation of
America, and Texas Ratepayers’ Organization to Save
Energy.

Somerset Perry (argued) and Jaime Jefferson, Deputy
Attorneys General; Susan S. Fiering, Supervising Deputy
Attorney General; Sally Magnani, Senior Assistant Attorney
General; Office of the Attorney General, Oakland,
California; Bryant B. Cannon, Deputy Attorney General;
Xavier Becerra, Attorney General; Office of the Attorney
6                     NRDC V. PERRY

General, San Francisco, California; Lisa Kwong and
Timothy Hoffman, Assistant Attorneys General; Patrick A.
Woods, Assistant Solicitor General; Environmental
Protection Bureau, Office of the Attorney General, Albany,
New York; George Jepsen, Attorney General; Robert Snook
and Matthew Levine, Assistant Attorneys General; Office of
the Attorney General, Hartford, Connecticut; Lisa Madigan,
Attorney General; Gerald T. Karr, Assistant Attorney
General; Attorney General’s Office, Chicago, Illinois; Janet
T. Mills, Attorney General; Susan P. Herman, Deputy
Attorney General; Office of the Attorney General, Augusta,
Maine; Brian E. Frosh, Attorney General; Steven M.
Sullivan, Solicitor General; Office of the Attorney General,
Baltimore, Maryland; Maura Healey, Attorney General;
Shennan Kavanaugh and I. Andrew Goldberg, Assistant
Attorneys General; Office of the Attorney General, Boston,
Massachusetts; Max Kieley, Assistant Attorney General,
Office of the Attorney General, St. Paul, Minnesota; Ellen F.
Rosenblum, Attorney General; Benjamin Gutman, Solicitor
General; Denise G. Fjordbeck, Attorney-in-Charge, Civil
Administrative Appeals; Jesse Ratcliffe, Assistant Attorney
General; Natural Resources Section, Oregon Department of
Justice, Salem, Oregon; Josh Shapiro, Attorney General;
Michael J. Fischer, Chief Deputy Attorney General; Office
of the Attorney General, Harrisburg, Pennsylvania; Thomas
J. Donovan Jr., Attorney General; Julio A. Thompson and
Laura B. Murphy, Assistant Attorneys General; Attorney
General’s Office, Montpelier, Vermont; Bob Ferguson,
Attorney General; Laura J. Watson, Senior Assistant
Attorney General; Office of the Attorney General, Olympia,
Washington; Karl A. Racine, Attorney General; Loren L.
AliKhan, Solicitor General; Office of the Attorney General,
Washington, D.C.; Zachary W. Carter, Corporation Counsel;
Susan E. Amron, Chief, Environmental Law Division; Haley
Stein, Counsel; New York City Law Department, New York,
                      NRDC V. PERRY                        7

New York; for Plaintiffs-Appellees People of the State of
California, California State Energy Resources Conservation
and Development Commission, State of New York, State of
Connecticut, State of Illinois, State of Maine, State of
Maryland, State of Massachusetts, State of Minnesota, State
of Oregon, State of Pennsylvania, State of Vermont, State of
Washington, District of Columbia, and City of New York.

Stuart Drake and C. Harker Rhodes IV, Kirkland & Ellis
LLP, Washington, D.C.; Mark E. McKane and Austin L.
Klar, Kirkland & Ellis LLP, San Francisco, California; for
Intervenor-Defendant-Appellant.


                        OPINION

WATFORD, Circuit Judge:

    These appeals arise from consolidated actions brought
by plaintiffs who seek to compel the United States
Department of Energy (DOE) to promulgate four energy-
conservation standards. The standards received final
approval by DOE at the end of the Administration of
President Obama, but thus far, under the Administration of
President Trump, DOE has declined to promulgate them.
The plaintiffs contend that a DOE regulation known as the
“error-correction rule,” 10 C.F.R. § 430.5, imposes upon
DOE a non-discretionary duty to publish the standards in the
Federal Register, and that its refusal to do so violates the
rule. The district court agreed and issued an order directing
DOE to publish the four standards in the Federal Register.
Natural Resources Defense Council, Inc. v. Perry,
302 F. Supp. 3d 1094 (N.D. Cal. 2018). We stayed that
order pending resolution of DOE’s appeal.
8                     NRDC V. PERRY

    Although both sides have advanced compelling
arguments in support of their respective positions, we find
the plaintiffs’ arguments more persuasive. We therefore
affirm the district court’s decision.

                              I

                              A

    We begin with an overview of the statutory and
regulatory framework. As relevant here, the Energy Policy
and Conservation Act (EPCA), 42 U.S.C. §§ 6291–6317,
authorizes DOE to establish energy-conservation standards
for certain consumer products and industrial equipment.
DOE establishes or amends energy-conservation standards
through      formal     notice-and-comment        rulemaking
proceedings. §§ 6306(a), 6316(a). An energy-conservation
standard is promulgated when DOE publishes a final rule
prescribing the standard in the Federal Register.

    A somewhat unusual provision of EPCA, known as the
“anti-backsliding” provision, prohibits DOE from
promulgating an amended standard that is less stringent than
the       preexisting      standard.            §§ 6295(o)(1),
6313(a)(6)(B)(iii)(I); see Natural Resources Defense
Council v. Abraham, 355 F.3d 179, 187 (2d Cir. 2004). As
DOE discovered during litigation in the Fifth Circuit, if a
standard contains inadvertent errors, the anti-backsliding
provision can make it difficult to correct those errors after
the final rule establishing the standard has been published in
the Federal Register.

    In 2016, DOE sought to address this problem by
adopting the error-correction rule. The rule creates a brief,
45-day window between DOE’s issuance of a final rule
establishing an energy-conservation standard and the rule’s
                      NRDC V. PERRY                         9

publication in the Federal Register. During that 45-day
period, DOE posts the rule on its website and invites
members of the public to identify any errors that should be
corrected before the standard is promulgated. 10 C.F.R.
§ 430.5(c)(1), (d)(1). The error-correction rule defines the
term “error” narrowly as “an aspect of the regulatory text of
a rule that is inconsistent with what the Secretary intended
regarding the rule at the time of posting,” and gives as
examples typographical, calculation, or numbering
mistakes. § 430.5(b). Requests for correction may not be
premised on “disagreement with a policy choice that the
Secretary has made,” and DOE will not consider any new
evidence submitted in connection with a correction request.
§ 430.5(d)(2)–(3). As DOE explained, the error-correction
process is not an opportunity to “seek to reopen issues that
DOE has already addressed or argue for policy choices
different from those reflected in the final rule.”
Establishment of Procedures for Requests for Correction of
Errors in Rules, 81 Fed. Reg. 26,998, 26,999 (May 5, 2016).

    The error-correction rule provides that, after the 45-day
period ends, the Secretary of Energy “may respond to a
request for correction . . . or address an Error discovered on
the Secretary’s own initiative by submitting to the Office of
the Federal Register either a corrected rule or the rule as
previously posted.” 10 C.F.R. § 430.5(e). The error-
correction rule addresses each of the three scenarios that can
arise upon completion of the error-correction process, and
specifies timeframes within which the Secretary “will”
submit the final rule for publication in the Federal Register:

       (f) Publication in the Federal Register.

          (1) If, after receiving one or more
       properly filed requests for correction, the
10                    NRDC V. PERRY

       Secretary decides not to undertake any
       corrections, the Secretary will submit the rule
       for publication as it was posted pursuant to
       paragraph (c)(1) of this section.

            (2) If the Secretary receives no properly
       filed requests after posting a rule and
       identifies no Errors on the Secretary’s own
       initiative, the Secretary will in due course
       submit the rule, as it was posted pursuant to
       paragraph (c)(1) of this section, to the Office
       of the Federal Register for publication. This
       will occur after the [45-day] period
       prescribed by paragraph (c)(2) of this section
       has elapsed.

           (3) If the Secretary receives a properly
       filed request after posting a rule pursuant to
       (c)(1) and determines that a correction is
       necessary, the Secretary will, absent
       extenuating circumstances, submit a
       corrected rule for publication in the Federal
       Register within 30 days after the period
       prescribed by paragraph (c)(2) of this section
       has elapsed.

§ 430.5(f)(1)–(3) (emphasis added).

                             B

    With that background in mind, we can turn to the facts
giving rise to this dispute. In December 2016, after lengthy
rulemaking proceedings, DOE finalized the four energy-
conservation standards at issue by posting on its website
final rules prescribing the standards. Each standard covers a
different set of products: portable air conditioners,
                           NRDC V. PERRY                               11

commercial packaged boilers, uninterruptible power
supplies, and air compressors. Each of the final rules was
signed by the appropriate DOE official and states that “[t]he
Secretary of Energy has approved publication of this final
rule.” The 45-day error-correction period ended on January
19, 2017, for the rule governing air compressors, and on
February 11, 2017, for the rules governing the other three
products.

     DOE received one minor correction request relating to
the rule for commercial packaged boilers (changing the
symbol “>” to “≥” in a table), and no correction requests for
the remaining three rules. Nevertheless, after the 45-day
error-correction period ended, DOE refused to submit any of
the rules to the Office of the Federal Register for publication.
It still has not done so, informing us in its brief and at oral
argument that the agency “is continuing to review” the rules.

    The plaintiffs are a group of States and municipalities as
well as several environmental and consumer organizations.
They brought suit against DOE under EPCA’s citizen-suit
provision, which, as relevant here, authorizes any person to
bring a civil action against an agency such as DOE “where
there is an alleged failure of such agency to perform an act
or duty under this part which is not discretionary.” 42 U.S.C.
§ 6305(a)(2). 1 The plaintiffs allege that the error-correction
rule imposes upon DOE a non-discretionary duty to publish
the four rules at issue in the Federal Register.



    1
      Section 6305(a)(2) provides: “Except as otherwise provided in
subsection (b) of this section, any person may commence a civil action
against . . . any Federal agency which has a responsibility under this part
where there is an alleged failure of such agency to perform any act or
duty under this part which is not discretionary.”
12                    NRDC V. PERRY

    The district court denied DOE’s motion to dismiss the
action and granted the plaintiffs’ motion for summary
judgment. The court held that it had jurisdiction to hear the
suit under § 6305(a)(2). That provision, the court concluded,
authorizes suits for enforcement of non-discretionary duties
imposed by regulations such as the error-correction rule; the
court rejected the government’s argument that the
provision’s scope is limited to duties imposed by statute.
302 F. Supp. 3d at 1097. The court also concluded that the
error-correction rule imposes upon DOE a non-discretionary
duty to publish the four rules at issue, and that DOE has
violated that duty by withholding publication. Id. at 1100–
01. The court accordingly ordered DOE to publish the four
rules in the Federal Register within 28 days.

                              II

    On appeal, DOE renews its challenges to the district
court’s assertion of jurisdiction under 42 U.S.C.
§ 6305(a)(2). DOE contends that the error-correction rule
does not impose a mandatory duty to publish final rules in
the Federal Register upon completion of the error-correction
process. And it contends that, even if the error-correction
rule imposes such a duty, the plaintiffs cannot invoke
§ 6305(a)(2) because that provision only authorizes suits for
the enforcement of non-discretionary duties imposed by
statute. Like the district court, we reject both of these
arguments.

                              A

    To invoke the district court’s jurisdiction under
§ 6305(a)(2), the plaintiffs must identify a failure by DOE to
perform an act or duty “which is not discretionary.”
42 U.S.C. § 6305(a)(2). They contend that DOE had a non-
discretionary duty to publish the four rules at issue upon
                      NRDC V. PERRY                        13

completion of the error-correction process. In asserting such
a duty, the plaintiffs acknowledge that, ordinarily, agencies
are free to withdraw a proposed rule before it has been
published in the Federal Register, even if the rule has
received final agency approval. See Kennecott Utah Copper
Corp. v. U.S. Department of Interior, 88 F.3d 1191, 1206
(D.C. Cir. 1996); Anne Joseph O’Connell, Agency
Rulemakings and Political Transitions, 105 Nw. U. L. Rev.
471, 529 (2011). Indeed, regulations governing the Office
of the Federal Register generally permit an agency to
withdraw a final rule even after it has been submitted to the
Office for publication, so long as the rule has not yet been
published. 1 C.F.R. § 18.13(a); see Kennecott, 88 F.3d
at 1206. In Kennecott, the D.C. Circuit held that an agency
could withdraw regulations that were submitted to the Office
of the Federal Register at any time up until the regulations
were made available for public inspection. 88 F.3d at 1205–
06. The government urges us to reach the same conclusion
here. But the regulations at issue in Kennecott were never
made available for public inspection with the expectation
that they would become final, as the rules here were. And,
of course, there could have been no argument in Kennecott
that the agency had a mandatory duty to publish the
regulations due to anything similar to the error-correction
rule.

    The district court held that DOE relinquished whatever
discretion it might have had to withhold publication of the
rules at issue here when it adopted the error-correction rule.
302 F. Supp. 3d at 1098. We think the plain language of the
error-correction rule supports that reading, and that the
absence of genuine ambiguity in the rule’s meaning
precludes us from deferring to DOE’s contrary
interpretation. See Kisor v. Wilkie, 139 S. Ct. 2400, 2415
(2019).
14                       NRDC V. PERRY

    The error-correction rule states that, at the end of the
error-correction process, the Secretary “will” submit the
final rule for publication in the Federal Register. 10 C.F.R.
§ 430.5(f)(1)–(3). The word “will,” like the word “shall,” is
a mandatory term, see Washington v. Harper, 494 U.S. 210,
221 (1990), unless something about the context in which the
word is used indicates otherwise. See Webber v. Crabtree,
158 F.3d 460, 461 (9th Cir. 1998) (per curiam). We see
nothing in the rule’s text or regulatory history to suggest that
the word “will” was meant to carry anything other than its
ordinary, mandatory connotation here.

     Section 430.5(f), titled “Publication in the Federal
Register,” is the most relevant provision. It addresses each
of the possible scenarios that could arise at the end of the
error-correction process: (1) no requests for correction are
received and the Secretary identifies no errors on his own;
(2) a request for correction is received but the Secretary
decides not to make any corrections; or (3) a request for
correction is received and the Secretary decides that a
correction is warranted. In each of those scenarios,
§ 430.5(f) states without qualification that the Secretary
“will submit the rule for publication,” “will in due course
submit the rule for publication,” or “will, absent extenuating
circumstances, submit a corrected rule for publication in the
Federal Register within 30 days.” 10 C.F.R. § 430.5(f)(1)–
(3). 2 In adopting the error-correction rule, DOE reiterated
the binding nature of these provisions: “The error correction
rule prescribes a timeline under which DOE will submit a

     2
       DOE has made clear that the phrase “absent extenuating
circumstances” in subsection (f)(3) qualifies the 30-day timeframe for
publication, not the duty to publish itself. See Notice of Partial Grant
and Partial Denial of Petitions to Amend the Error Correction Rule,
81 Fed. Reg. 57,745, 57,750 (Aug. 24, 2016).
                       NRDC V. PERRY                         15

rule to the Office of the Federal Register for publication.”
Notice of Partial Grant and Partial Denial of Petitions to
Amend the Error Correction Rule, 81 Fed. Reg. 57,745,
57,750 (Aug. 24, 2016) (emphasis added).

     Given the mandatory character of these pronouncements,
it would be unnatural to read the word “will” in § 430.5(f) to
mean “may.” Although § 430.5(e) states that “[t]he
Secretary may respond to a request for correction . . . or
address an Error discovered on the Secretary’s own
initiative,” even that provision makes clear that the
Secretary’s response is limited to one of two options:
“submitting to the Office of the Federal Register either a
corrected rule or the rule as previously posted.” 10 C.F.R.
§ 430.5(e) (emphasis added). We thus agree with the district
court’s observation that, “once the Department has posted an
energy standard for error correction and the time to submit
requests for correction has passed, subsection (f) of the Rule
gives the Department only two options: publish the standard
as posted, or correct any errors in the standard and publish it
as corrected.” 302 F. Supp. 3d at 1098.

    DOE nonetheless contends that, as used in § 430.5(f), the
word “will” was intended to be merely descriptive rather
than prescriptive. DOE reads § 430.5(f) as describing what
the agency anticipates will ordinarily occur at the end of the
error-correction process, leaving the Secretary free to do
something different if he so chooses. We do not think that
is a plausible reading of the provision’s language. As the
plaintiffs point out, when the word “will” is used elsewhere
in the error-correction rule, it is used in its mandatory sense,
to prescribe what the agency is required (or forbidden) to do.
For example, § 430.5(c) states that the Secretary “will cause
a rule under the Act to be posted on a publicly-accessible
Web site” to commence the error-correction process, and
16                     NRDC V. PERRY

that the Secretary “will not submit a rule for publication in
the Federal Register” during the 45-day period that follows.
10 C.F.R. § 430.5(c)(1)–(2). DOE does not claim that these
provisions are merely descriptive of ordinary practice, or
that the Secretary is free to ignore their commands. Indeed,
in the one instance where the error-correction rule clearly
does seek to describe what the agency anticipates will
ordinarily occur, rather than to prescribe a required action,
the rule says exactly that: “[T]he Secretary will ordinarily
designate an effective date for a rule under this section that
is no less than 30 days after the publication of the rule in the
Federal Register.” § 430.5(f)(5) (emphasis added).

    DOE argues that we should not read the error-correction
rule as imposing a non-discretionary duty to publish because
the rule does not explicitly divest the Secretary of the
discretion he would otherwise possess to withdraw a final
rule prior to publication. We confronted and rejected a
similar argument in Sacks v. Office of Foreign Assets
Control, 466 F.3d 764 (9th Cir. 2006). There, the Office of
Foreign Assets Control (OFAC) adopted a regulation stating
that if the agency imposed a penalty that remained unpaid
after 30 days, “the matter shall be referred to the United
States Department of Justice for appropriate action to
recover the penalty in a civil suit in a Federal district court.”
Id. at 778 (quoting 31 C.F.R. § 575.705 (2002)). OFAC
argued that, because the regulation was silent about using
private collection agencies, it retained the discretion to refer
collection matters to them rather than to the Department of
Justice. We labeled that argument “patently absurd.” Id. at
780. We held that the regulation’s use of the word “shall”
unambiguously imposed “a mandatory duty that is not
subject to discretion.” Id. at 778. And we refused to require
that an agency “articulate all of the acts the agency may not
engage in simply to guarantee that mandatory prescriptions
                      NRDC V. PERRY                         17

are followed.” Id. at 780. That reasoning applies with equal
force to the error-correction rule. In our view, the rule’s use
of the word “will” unambiguously imposes a mandatory duty
that constrains whatever discretion the Secretary might
otherwise have possessed.

    We find DOE’s remaining argument unpersuasive. It is
true that the error-correction rule does not set date-certain
deadlines by which the Secretary must submit a rule for
publication after the 45-day error-correction period ends.
However, we do not think that fact renders the duty to
publish discretionary. Section 430.5(f)(3) states that when
the agency decides a correction is warranted, the Secretary
will generally submit the corrected rule for publication
within 30 days, “absent extenuating circumstances.”
10 C.F.R. § 430.5(f)(3). That general 30-day deadline
informs the interpretation of subsections (f)(1) and (f)(2),
which apply when the agency decides not to make any
corrections. Those provisions state that the Secretary will
submit the rule for publication as it was originally posted,
either without specifying any timeframe for doing so (when
a request for correction is received but not acted upon) or “in
due course” (when no requests for correction are received).
§ 430.5(f)(1)–(2). In either scenario, though, 30 days would
necessarily mark the outer limit for performing the
ministerial task of submitting the original rule for
publication, because the agency bound itself to submit a
corrected rule within that timeframe in all but unusual
circumstances.

    Here, the Secretary had a non-discretionary duty to
submit all four rules for publication in the Federal Register
within 30 days after the error-correction process ended.
DOE received a request for correction as to only one of the
rules, and the agency has not claimed that extenuating
18                    NRDC V. PERRY

circumstances precluded it from resolving that request
within the normal 30-day timeframe. As to the other three
rules for which no requests were received, the Secretary was
required to submit the original rule for publication “in due
course,” § 430.5(f)(2), a period that elapsed at the latest
30 days after the 45-day error-correction period ended. By
delaying publication of the four rules beyond the period
permitted under the error-correction rule, DOE has violated
the non-discretionary duty imposed by its own regulation.

                              B

    DOE next argues that, even if the error-correction rule
imposes upon it a non-discretionary duty to publish, the
plaintiffs are still precluded from bringing this action under
42 U.S.C. § 6305(a)(2). That is so, the agency asserts,
because the provision requires the plaintiffs to identify an
alleged failure by DOE to perform an “act or duty under this
part,” meaning Part A of Subchapter III, Chapter 77
(42 U.S.C. §§ 6291–6309). In the agency’s view, the phrase
“under this part” refers solely to duties imposed by statute,
not to duties imposed by regulations such as the error-
correction rule.

    We do not find DOE’s reading of § 6305(a)(2)
convincing. As we read it, the phrase “under this part”
encompasses duties imposed by statute and regulation alike,
so long as the regulation in question was issued under Part
A of Subchapter III. It is undisputed that DOE promulgated
the error-correction rule under the authority granted to it by
Part A. See Establishment of Procedures for Requests for
Correction of Errors in Rules, 81 Fed. Reg. at 27,005
(“Authority: 42 U.S.C. §§ 6291–6309; 28 U.S.C. § 2461
note.”).
                      NRDC V. PERRY                        19

    DOE’s reading of § 6305(a)(2) as limited to statutory
duties is unconvincing for several reasons. First, throughout
EPCA, Congress consistently used the phrase “under this
part” or “under this section” when referring to requirements
established by regulation. For example, EPCA refers to
energy-conservation standards “prescribed under this part,”
42 U.S.C. § 6302(a)(5); final rules “published under this
part,” § 6295(n)(5)(B); and test procedures prescribed
“under this section,” § 6314(b). In contrast, when Congress
wanted to refer only to statutory provisions, it used distinct
phrases such as “of this part” or “established in.” For
example, EPCA authorizes the Secretary and the Federal
Trade Commission to “issue such rules as each deems
necessary to carry out the provisions of this part.” § 6298
(emphasis added).         And § 6302 refers to energy-
conservation standards “established in or prescribed under
this part,” to distinguish between standards imposed by
statute and those imposed by regulation. § 6302(a)(5)
(emphasis added). This consistent pattern supports the view
that Congress used the phrase “under this part” to include
regulatory obligations.       See Sierra Club v. Leavitt,
355 F. Supp. 2d 544, 556–57 (D.D.C. 2005) (reaching the
same conclusion with respect to the Clean Air Act’s
materially identical citizen-suit provision).

     Second, other than § 6305(a)(2), DOE has not identified
a single provision in which Congress supposedly used the
phrase “under this part” to refer exclusively to statutory
provisions. The plaintiffs, on the other hand, have identified
at least one other provision of EPCA that would be rendered
nonsensical if we adopted DOE’s reading of the phrase. In
§ 6309, Congress authorized the appropriation of specific
sums to the Secretary for fiscal years 1976–1979 “to carry
out his responsibilities under this part.” 42 U.S.C § 6309(a)
(emphasis added). DOE has not explained why, under its
20                    NRDC V. PERRY

reading, Congress would have authorized the Secretary to
spend the appropriated funds to carry out his statutory
responsibilities but not his regulatory responsibilities.

    Third, far from supporting DOE’s reading of
§ 6305(a)(2), we think the language of a neighboring
subsection, § 6305(a)(1), confirms that the phrase “under
this part” encompasses regulatory duties. Section 6305(a)(1)
authorizes citizen suits against “any manufacturer or private
labeler who is alleged to be in violation of any provision of
this part or any rule under this part.” 42 U.S.C. § 6305(a)(1).
DOE asks us to contrast subsection (a)(1)’s use of the phrase
“any rule under this part” with subsection (a)(2)’s use of the
phrase “any act or duty under this part,” and to conclude that
Congress must have intended to exclude regulatory duties
from the sweep of (a)(2) because (a)(2) does not mention
“rules.” We do not think that conclusion follows at all. The
key phrase in both provisions is “under this part”: Just as
rules are “under this part” because they are established
through regulations promulgated under the authority of Part
A, so too with duties. Indeed, the language of subsection
(a)(1) itself reinforces the pattern discussed earlier, with
Congress using the phrase “of this part” to refer solely to
statutory provisions, and the phrase “under this part” when
referring to regulatory obligations.

    DOE relies on Kucana v. Holder, 558 U.S. 233 (2010),
to support its position, but in our view that case is readily
distinguishable. In Kucana, the Supreme Court interpreted
a provision that precluded judicial review of any decision by
the Attorney General “the authority for which is specified
under this subchapter” to be in the discretion of the Attorney
General. 8 U.S.C. § 1252(a)(2)(B)(ii) (emphasis added).
The Court held that this provision barred judicial review
only of “determinations made discretionary by statute,” not
                       NRDC V. PERRY                      21

those “declared discretionary by the Attorney General
himself through regulation.” 558 U.S. at 237. But none of
the reasons the Court gave for reaching that conclusion
applies to the statute before us. The Court in Kucana
stressed that § 1252(a)(2)(B) is “sandwiched between” two
other subsections that contain only statutory references,
leading one to “expect that it, too, would cover statutory
provisions alone.” Id. at 246. In addition, the Court noted
that the statute had been enacted against the well-settled
“presumption favoring judicial review of administrative
action,” which requires clear and convincing evidence to
dislodge. Id. at 251–52. Finally, the Court emphasized, as
a “paramount factor” in its decision, the separation-of-
powers concerns that would have been raised by construing
the statute to allow the Attorney General to place his own
decisions beyond judicial review “simply by issuing a
regulation declaring those decisions ‘discretionary.’” Id. at
237, 252. DOE does not contend that any of these
considerations should (or could) drive the interpretation of
the statute at issue here.

     We hold that § 6305(a)(2) provides the necessary “clear
and unequivocal waiver” of sovereign immunity from
citizen suits predicated on a non-discretionary duty imposed
either by statute or regulation. U.S. Department of Energy
v. Ohio, 503 U.S. 607, 619 (1992). The plaintiffs therefore
properly invoked EPCA’s citizen-suit provision to challenge
DOE’s failure to perform its non-discretionary duty to
submit the four rules at issue for publication in the Federal
Register.

                   *         *          *

    The unopposed motion for judicial notice filed by
Intervenor Air-Conditioning, Heating, and Refrigeration
Institute is GRANTED. Upon issuance of the mandate from
22                    NRDC V. PERRY

this court, the stay entered on April 11, 2018 (Dkt. 42 in Case
No. 18-15380; Dkt. 38 in Case No. 18-15475), is
DISSOLVED.

     AFFIRMED.
