 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued March 25, 2014                  Decided May 13, 2014

                         No. 13-1212

                  WILDEARTH GUARDIANS,
                       PETITIONER

                              v.

       UNITED STATES ENVIRONMENTAL PROTECTION
                   AGENCY, ET AL.,
                     RESPONDENTS

          NATIONAL MINING ASSOCIATION, ET AL.,
                    INTERVENORS


       On Petition for Review of a Final Action of the
       United States Environmental Protection Agency


     Samantha Ruscavage-Barz argued the cause and filed the
briefs for petitioner. James J. Tutchton entered an appearance.

    Kim Smaczniak, Attorney, Environmental Defense
Section, U.S. Department of Justice, argued the cause for
respondents. With her on the brief were Robert G. Dreher,
Acting Assistant Attorney General, Environment and Natural
Resources Division, and Scott Jordan, Office of General
Counsel.
                                2
    Andrew C. Emrich, Emily C. Schilling, Peter S. Glaser,
and Merril J. Hirsh were on the brief for intervenors National
Mining Association, et al. in support of respondents.

   Before: GRIFFITH, Circuit Judge, and EDWARDS and
RANDOLPH, Senior Circuit Judges.

   Opinion for the Court filed by Senior Circuit Judge
EDWARDS.

     EDWARDS, Senior Circuit Judge: On June 16, 2010,
Earthjustice, on behalf of WildEarth Guardians (“Guardians”)
and other environmental groups, petitioned the Environmental
Protection Agency (“EPA”) to add coal mines to the regulated
list of stationary source categories under the Clean Air Act,
42 U.S.C. § 7411(b)(1)(A). The petition sought to have EPA
initiate a rulemaking to: “(1) list coal mines as a category of
stationary sources that emit air pollution which may
reasonably be anticipated to endanger public health or
welfare; (2) establish federal standards of performance for
new and modified sources within the newly listed stationary
source category for coal mines; and (3) establish federal
standards of performance to address methane emissions from
existing sources within the newly listed stationary source
category for coal mines.” Pet’rs’ Br. at 7. EPA denied the
petition on April 30, 2013. Letter from Bob Perciasepe,
Acting Administrator, to Edward B. Zukoski, Staff Attorney,
Earthjustice (Apr. 30, 2013) (“Letter Denying Petition”),
reprinted in Joint Appendix (“J.A.”) 40-44. Guardians now
seeks review of EPA’s action.

     In denying the petition for rulemaking, EPA explained
that it “must prioritize its actions in light of limited resources
and ongoing budget uncertainties, and at this time, cannot
commit to conducting the process to determine whether coal
                               3
mines should be added to the list of categories under” the
Clean Air Act. Notice of Final Action on Petition From
Earthjustice To List Coal Mines as a Source Category and To
Regulate Air Emissions From Coal Mines, 78 Fed. Reg.
26,739 (May 8, 2013). EPA made it clear, however, that the
denial was not a determination as to whether coal mines
should be regulated as sources of air pollutants. Letter
Denying Petition, J.A. 40. The agency also indicated that it
might, in the future, initiate a rulemaking proceeding to
address the question raised by Guardians, but it would not do
so now. Id.

     Guardians contends that EPA’s reasons for denying the
petition for rulemaking do not “conform to the authorizing
statute,” as required under Massachusetts v. EPA, 549 U.S.
497, 533 (2007). We disagree. On the record before us, we
find that EPA’s action easily passes muster under the
“extremely limited” and “highly deferential” standard that
governs our review of an agency’s denial of a rulemaking
petition. Id. at 527-28 (quoting Nat’l Customs Brokers &
Forwarders Ass’n of America, Inc. v. United States, 883 F.2d
93, 96 (D.C. Cir. 1989)). “[A]n agency has broad discretion to
choose how best to marshal its limited resources and
personnel to carry out its delegated responsibilities,”
Massachusetts v. EPA, 549 U.S. at 527 (citation omitted),
which means that EPA has discretion to determine the timing
and priorities of its regulatory agenda, id. at 533. EPA
provided a “reasonable explanation as to why it cannot or will
not exercise its discretion” to regulate coal mines at this time.
Id. at 533. And the reasons given are consistent with the
agency’s delegated authority and supported by the record. We
therefore deny the petition for review.
                               4
                      I.      BACKGROUND

     Section 7411 of the Clean Air Act addresses air pollution
prevention and control, and sets forth air quality and
emissions limitations. Section 7411(b), which is at issue in
this case, provides in relevant part that:

    (1)(A) The Administrator shall . . . publish (and from
    time to time thereafter shall revise) a list of categories of
    stationary sources. He shall include a category of sources
    in such list if in his judgment it causes, or contributes
    significantly to, air pollution which may reasonably be
    anticipated to endanger public health or welfare.

    (B) Within one year after the inclusion of a category of
    stationary sources in a list under subparagraph (A), the
    Administrator shall publish proposed regulations,
    establishing Federal standards of performance for new
    sources within such category. The Administrator shall
    afford interested persons an opportunity for written
    comment on such proposed regulations. After
    considering such comments, he shall promulgate, within
    one year after such publication, such standards with such
    modifications as he deems appropriate. The
    Administrator shall, at least every 8 years, review and, if
    appropriate, revise such standards following the
    procedure required by this subsection for promulgation
    of such standards. Notwithstanding the requirements of
    the previous sentence, the Administrator need not review
    any such standard if the Administrator determines that
    such review is not appropriate in light of readily
    available information on the efficacy of such standard.
    Standards of performance or revisions thereof shall
    become effective upon promulgation.
                             5
42 U.S.C. § 7411(b)(1)(A), (B).

    As noted above, on June 16, 2010, Earthjustice, on behalf
of Guardians and other environmental groups, petitioned EPA
to add coal mines to the regulated list of stationary source
categories under § 7411(b)(1)(A). Petition for Rulemaking
Under the Clean Air Act, reprinted in J.A. 1-27. The petition
asserted that coal mines should be regulated under the Clean
Air Act because they account for 10.5% of the total methane
emissions in the United States. Id. at J.A. 5-7. The petition
also pointed out that coal mines emit particulate matter,
nitrogen oxides, and volatile organic compounds, all
pollutants that EPA regulates through National Ambient Air
Quality Standards (“NAAQS”). Id. at J.A. 10-14. It also
asserted that orange nitrogen dioxide clouds have been
observed in the areas surrounding mining operations, id. at
J.A. 15-18, and that the Bureau of Land Management
(“BLM”) has recognized the danger of nitrogen dioxide
emissions from the blasting involved in coal mining, id. at
J.A. 14.

     On December 27, 2010, WildEarth Guardians sent a
letter to EPA providing supplemental information in support
of the petition for rulemaking. Letter from Jeremy Nichols,
Climate and Energy Program Director, WildEarth
Guardians, to Lisa Jackson, EPA Administrator (Dec. 27,
2010), reprinted in J.A. 28-39. This submission offered data
showing that coal mines contribute to nitrogen oxide,
particulate matter, and ozone levels exceeding NAAQs in the
Powder River Basin of southeastern Montana and
northeastern Wyoming. Id. at 30-37.

     In rejecting the petition for rulemaking, EPA made it
clear that the denial was “not based on a determination as to
whether the emissions from coal mines cause or significantly
                               6
contribute to air pollution that may reasonably be anticipated
to endanger public health and welfare.” Letter Denying
Petition, J.A. 40. Rather, EPA stated that “resource
limitations and the necessity of completing court-ordered
rulemaking actions have continued to hinder” the agency’s
effort to determine whether to add coal mines to the regulated
list of stationary source categories under § 7411(b)(1)(A). Id.
at J.A. 42. Specifically, the agency explained that the budget
for EPA’s Office of Air Quality Planning and Standards was
reduced by 12% in real dollars between 2006 and 2013, and
its staff levels had also declined. Id. In addition, “automatic
reductions in federal agency resources . . . h[ad] further
reduced the EPA’s 2013 budget and h[ad] necessitated
significant reductions in a number of regulatory efforts
already underway.” Id. According to EPA, the Office of Air
Quality Planning and Standards has 45 nationally applicable
stationary source rules due for review or promulgation by
September 2014, and it is facing challenges to 15 other
recently issued rules. Id.

      In light of these resource constraints, EPA stated that it
was “taking a common-sense, step-by-step approach intended
to obtain the most significant greenhouse-gas-emissions
reductions through using the most cost-effective measures
first.” Id. at J.A. 43. This means that, in allocating resources
available for addressing air pollution, EPA is focusing first on
promulgating standards for transportation and electricity
systems because these are the largest sources, responsible for
more than 60% of the greenhouse gas emissions in the United
States in 2011. Id. at 43 & n.9. “In contrast to the electricity-
generating sector, the coal-mines category represents about
1 percent of total 2011 U.S. greenhouse gas-emissions.” Id. at
43. The EPA’s Letter Denying Petition concluded that, “[a]t
this point, the agency believes it must address other, higher-
priority actions before it can commit to consider whether to
                                7
list coal mines as a stationary-source category. . . .” Id. at J.A.
44. EPA indicated that, “[i]n the future,” the agency “may
initiate the process for such a determination, but the agency
has decided that it will not do so now.” Id. at J.A. 40.

                          II.       ANALYSIS

    A. Standard of Review

     In Massachusetts v. EPA, the Court confirmed that
review of an agency’s denial of a petition for rulemaking is
very narrow: “Refusals to promulgate rules are . . . susceptible
to judicial review, though such review is extremely limited
and highly deferential.” 549 U.S. at 527-28 (quotations
omitted). The Court’s decision is also clear in setting the
parameters for review with respect to petitions for rulemaking
under the Clean Air Act:

    [O]nce EPA has responded to a petition for rulemaking,
    its reasons for action or inaction must conform to the
    authorizing statute. Under the clear terms of the Clean
    Air Act, EPA can avoid taking further action only if it
    determines that greenhouse gases do not contribute to
    climate change or if it provides some reasonable
    explanation as to why it cannot or will not exercise its
    discretion to determine whether they do. To the extent
    that this constrains agency discretion to pursue other
    priorities of the Administrator or the President, this is the
    congressional design.

Id. at 533 (emphasis added) (citations omitted).

    In assessing Guardians’ petition for review in line with
established precedent, we must determine whether EPA
exercised discretion pursuant to its delegated authority under
                               8
the Clean Air Act. We must also determine whether the
agency “adequately explained the facts and policy concerns it
relied on and [whether] . . . those facts have some basis in the
record.” WWHT, Inc. v. F.C.C., 656 F.2d 807, 817 (D.C. Cir.
1981). And, as we have made clear in the past, “[w]e will
overturn an agency’s decision not to initiate a rulemaking
only for compelling cause, such as plain error of law or a
fundamental change in the factual premises previously
considered by the agency.” Nat’l Customs Brokers &
Forwarders Ass’n, 883 F.2d at 96-97 (citations omitted).

    B. EPA’s Reasons for Denying the Petition for
       Rulemaking are Reasonable, Supported by the
       Record, and Consistent with the Authorizing
       Statute.

     The Court’s decision in Massachusetts v. EPA overturned
EPA’s denial of a petition to regulate new vehicle emissions
under the Clean Air Act. 549 U.S. at 534. EPA concluded that
it lacked authority to regulate these emissions because, in its
view, carbon dioxide is not an “air pollutant” under the Clean
Air Act. Id. at 528. The Court held that EPA misinterpreted its
authorizing statute in reaching this conclusion. Id. at 528-29.
EPA also reasoned that, even assuming that it had the
necessary statutory authority, it would not regulate carbon
dioxide because other Executive Branch programs were
providing “an effective response to the threat of global
warming,” regulating new vehicle greenhouse gas emissions
might impair the President’s ability to negotiate with
developing nations, and this would be an “inefficient,
piecemeal approach” to addressing climate change. Id. at 533
(quotations omitted). The Court held that these “policy
judgments” fell short of “a reasoned justification for declining
to form a scientific judgment.” Id. at 533-34.
                              9
    Guardians argues that, “[a]s in Massachusetts [v. EPA],
the agency here justified its failure to make the required
scientific and technical determination on policy grounds, with
EPA citing its desire to work on other rulemakings that it
deems to be a higher priority, and budgetary constraints.”
Pet’rs’ Br. at 33. Guardians thus contends that EPA’s action
cannot survive review pursuant to the principles enunciated in
Massachusetts v. EPA. We are not persuaded.

    EPA’s reasons for denying the petition for rulemaking in
this case differ in important respects from the reasons it
proffered in Massachusetts v. EPA. First, in Massachusetts v.
EPA, the agency incorrectly determined that it had no
authority to regulate carbon dioxide in motor vehicle
emissions as an “air pollutant.” In this case, EPA has reached
no such conclusion with respect to regulating emissions from
coal mines. Rather, EPA has made it clear here that the
question whether to list coal mines has yet to be decided. This
difference is significant because the Court in Massachusetts v.
EPA recognized that an agency has “significant latitude as to
the manner, timing, content, and coordination of its
regulations. . . .” 549 U.S. at 533 (emphasis added). EPA’s
decision in this case is about timing, not about whether to
regulate coal mines. The agency’s statutory authority to
regulate is not an issue in this case.

    Second, in Massachusetts v. EPA, the Court rejected the
agency’s alternative ground that, even if EPA possessed
authority to regulate, it would decline to do so because
regulation would conflict with other administration priorities.
549 U.S. at 533-34. As noted above, EPA had argued “that a
number of voluntary Executive Branch programs already
provide an effective response to the threat of global warming,
that regulating greenhouse gases might impair the President's
ability to negotiate with ‘key developing nations’ to reduce
                               10
emissions, and that curtailing motor-vehicle emissions would
reflect ‘an inefficient, piecemeal approach to address the
climate change issue.’” Id. at 533 (citations omitted). The
Supreme Court rejected these grounds because “it is evident
they have nothing to do with whether greenhouse gas
emissions contribute to climate change. Still less do they
amount to a reasoned justification for declining to form a
scientific judgment.” Id. at 533-34.

    It is noteworthy, however, that the Court in Massachusetts
v. EPA did not say that EPA was obliged to pursue
rulemaking to determine whether greenhouse gas emissions
contribute to climate change. Rather, the Court was quite
plain in saying that, “[u]nder the clear terms of the Clean Air
Act, EPA can avoid taking further action . . . if it provides
some reasonable explanation as to why it cannot or will not
exercise its discretion to determine whether they do.” Id. at
533.

    In Massachusetts v. EPA, the agency’s reasons for
declining to regulate new vehicle emissions were beyond the
scope of its delegated authority. In this case, EPA’s reasons
for denying the petition for rulemaking are entirely consistent
with the agency’s duties under § 7411. The statute says that
the Administrator shall “from time to time” revise the list of
categories of stationary sources of air pollutants.
§ 7411(b)(1)(A). And, under the terms of the statute, the
Administrator is authorized to list a source if “in his judgment
it causes, or contributes significantly to, air pollution which
may reasonably be anticipated to endanger public health or
welfare.” Id. This language – “from time to time” and “in his
judgment” – implies that the Administrator may exercise
reasonable discretion in determining when to add a new
source to the list of regulated air pollutants. In our view, the
statute affords agency officials discretion to prioritize sources
                              11
that are the most significant threats to public health to ensure
effective administration of the agency’s regulatory agenda.

    EPA’s decision to focus on more significant sources of air
pollutants before addressing coal mines is consistent with the
statutory objective of reducing hazardous emissions overall.
EPA explained that a greater reduction in emissions will be
achieved by focusing on electricity generating sectors, which
account for 60% of greenhouse gas emissions, than coal
mines, which account for 1%. Diverting resources from
regulating the most significant sources of air pollution to
regulate less-significant sources might increase overall
emissions. This would be contrary to the agency’s mandate
under § 7411. See Br. for Resp’t at 19 (“EPA is diligently
implementing its varied obligations under the relevant
statutory provision but cannot, because of resource
limitations, undertake immediately the additional regulatory
action requested by petitioner without sacrifice to its ongoing,
higher-priority activities.”); see also Nat’l Cong. of Hispanic
Am. Citizens (El Congreso) v. Marshall, 626 F.2d 882, 889
(D.C. Cir. 1979) (“With its broader perspective, and access to
a broad range of undertakings, and not merely the program
before the court, the agency has a better capacity than the
court to make the comparative judgments involved in
determining priorities and allocating resources.”).

    This case is similar to Defenders of Wildlife v. Gutierrez,
532 F.3d 913 (D.C. Cir. 2008). In that case, the court rejected
a challenge to the National Marine Fisheries Service
(“NMFS”)’s denial of a petition for emergency rulemaking to
impose speed restrictions to protect the right whale from
boating traffic. NMFS denied the petition for rulemaking on
the ground that imposing emergency restrictions would divert
resources from, and delay development of, a more
comprehensive strategy for protecting the whale population.
                               12
Id. at 920. The agency explained that, “instead of imposing
measures in a piecemeal fashion,” its comprehensive strategy
would be more effective in the long term. Id. (quotations
omitted).

    In upholding the agency’s action, the decision in
Defenders of Wildlife stated that the agency’s reason for
denying the petition for rulemaking showed it “was well
aware of its mandate to protect right whales and was pursuing
it by initiating a full notice-and-comment rulemaking on
speed restrictions that would potentially be even lower than
the ones proposed by petitioners.” Id. at 921. The decision
concluded that the agency’s determination “to focus its
resources on a comprehensive strategy” was “reasoned and
adequately supported by the record.” Id. Likewise, in this
case, we decline to second-guess EPA’s decision to prioritize
regulatory actions in a way that best achieves the objectives of
§ 7411.

    The reasons supporting EPA’s action in this case show
that that the agency is diligently implementing § 7411. EPA
submitted evidence of its budgetary and staff constraints,
explained that it has 45 mandatory rulemakings in progress or
under review, and concluded that, in light of these constraints,
the best course of action is to prioritize sectors that emit more
air pollutants. Guardians apparently believes that, even if EPA
has good reasons for prioritizing its regulatory agenda, it
cannot do so if this will delay a rulemaking proceeding to list
coal mines as a category of stationary sources that emit air
pollution. Guardians’ postion is contrary to precedent. We
find that EPA’s action was within the scope of its statutory
authority, consistent with the record, and supported by
reasoned decisionmaking.         Therefore, pursuant to the
extremely limited and highly deferential standard that governs
                              13
our review of an agency’s denial of a rulemaking petition, we
deny the petition for review.

                       III.   CONCLUSION

    For the reasons set forth above, the petition for review is
hereby denied.
