             Opinions of the Colorado Supreme Court are available to the
         public and can be accessed through the Judicial Branch’s homepage at
           http://www.courts.state.co.us. Opinions are also posted on the
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                                                      ADVANCE SHEET HEADNOTE
                                                                 January 14, 2019

                                      2019 CO 3

No. 17SC297, COGCC v. Martinez —Administrative Law and Procedure—Mines and
Minerals.

      This case requires the court to decide whether, in accordance with the Colorado

Oil and Gas Conservation Act (the “Act”), section 34-60-102(1)(a)(I), C.R.S. (2018), the

Colorado Oil and Gas Conservation Commission (the “Commission”) properly declined

to engage in rulemaking to consider a rule proposed by Respondents.

      Respondents proposed a rule that, among other things, would have precluded the

Commission from issuing any permits for the drilling of an oil and gas well “unless the

best available science demonstrates, and an independent, third-party organization

confirms, that drilling can occur in a manner that does not cumulatively, with other

actions, impair Colorado’s atmosphere, water, wildlife, and land resources, does not

adversely impact human health, and does not contribute to climate change.”

      After soliciting and receiving public comment and allowing interested parties to

be heard, the Commission declined to engage in rulemaking to consider this proposed

rule because, among other things, (1) the rule would have required the Commission to

readjust the balance purportedly crafted by the General Assembly under the Act and
conditioned new oil and gas drilling on a finding of no cumulative adverse impacts, both

of which the Commission believed to be beyond its statutory authority, and (2) the

Commission was already working with the Colorado Department of Public Health and

Environment (“CDPHE”) to address the concerns to which the rule was directed and

other Commission priorities took precedence over the proposed rulemaking at this time.

The Denver District Court upheld the Commission’s decision, but in a split, published

decision, a division of the Court of Appeals reversed the district court’s order. Martinez v.

Colo. Oil & Gas Conservation Comm’n, 2017 COA 37, __ P.3d __.

       The supreme court now reverses the division’s judgment and concludes that the

Commission properly declined to engage in rulemaking to consider Respondents’

proposed rule. The court reaches this conclusion for three primary reasons. First, a

court’s review of an administrative agency’s decision as to whether to engage in

rulemaking is limited and highly deferential.         Second, the Commission correctly

determined that, under the applicable language of the Act, it could not properly adopt

the rule proposed by Respondents. Specifically, as the Commission recognized, the

pertinent provisions do not allow it to condition all new oil and gas development on a

finding of no cumulative adverse impacts to public health and the environment. Rather,

the provisions make clear that the Commission is required (1) to foster the development

of oil and gas resources, protecting and enforcing the rights of owners and producers,

and (2) in doing so, to prevent and mitigate significant adverse environmental impacts

to the extent necessary to protect public health, safety, and welfare, but only after taking

into consideration cost-effectiveness and technical feasibility. Finally, in declining to
engage in rulemaking, the Commission reasonably relied on the facts that it was already

working with the CDPHE to address the concerns underlying Respondents’ proposed

rule and that other Commission priorities took precedence at this time.
                     The Supreme Court of the State of Colorado
                     2 East 14th Avenue • Denver, Colorado 80203

                                       2019 CO 3

                          Supreme Court Case No. 17SC297
                        Certiorari to the Colorado Court of Appeals
                         Court of Appeals Case No. 16CA564

                                       Petitioners:

 Colorado Oil and Gas Conservation Commission, American Petroleum Institute, and
                        Colorado Petroleum Association,

                                            v.

                                     Respondents:

  Xiuhtezcatl Martinez, Itzcuahtli Roske-Martinez, Sonora Brinkley, Aerielle Deering,
 Trinity Carter, Jamirah DuHamel, and Emma Bray, minors appearing by and through
their legal guardians Tamara Roske, Bindi Brinkley, Eleni Deering, Jasmine Jones, Robin
                               Ruston, and Diana Bray.

                                  Judgment Reversed
                                        en banc
                                    January 14, 2019


Attorneys for Petitioner Colorado Oil and Gas Conservation Commission:
Philip J. Weiser, Attorney General
John E. Matter, Jr., Senior Assistant Attorney General
Marian C. Larsen, Assistant Attorney General
Kyle W. Davenport, Assistant Attorney General
      Denver, Colorado

Attorneys for Petitioners American Petroleum Institute and Colorado Petroleum
Association:
Hogan Lovells US LLP
Jennifer L. Biever
Jessica Black Livingston
Dale Ratliff
      Denver, Colorado
Hogan Lovells US LLP
Catherine E. Stetson
     Washington, District of Columbia

Ryley Carlock & Applewhite
Richard C. Kaufman
Julie A. Rosen
Matthew K. Tieslau
      Denver, Colorado

Attorneys for Respondents:
Katherine Merlin
     Boulder, Colorado

Wild Earth Advocates
Julia Olson
      Eugene, Oregon

MindDrive Legal Services, LLC
James Daniel Leftwich
    Boulder, Colorado

Attorneys for Amici Curiae Alliance of Nurses for Healthy Environments &
Physicians for Social Responsibility:
Earthjustice
Joel Minor
Michael S. Freeman
      Denver, Colorado

Attorneys for Amicus Curiae The Board of County Commissioners of Adams County,
Colorado:
Heidi Miller, Adams County Attorney
     Brighton, Colorado

Goldman, Robbins, Nicholson & Mack, P.C.
Jeffery P. Robbins
      Durango, Colorado

Attorneys for Amicus Curiae The Chamber of Commerce of the United States of
America:
Kittredge LLC
Daniel D. Domenico
Michael Francisco
      Denver, Colorado
                                        2
Attorneys for Amicus Curiae The Colorado Alliance Mineral and Royalty Owners:
Visani Bargell LLC
Cynthia L. Bargell
     Dillon, Colorado

Attorneys for Amici Curiae Colorado Farm Bureau, Denver Metro Chamber of
Commerce, Associated Governments of Northwest Colorado, and Town of Rangely,
Colorado:
Brownstein Hyatt Farber Schreck, LLP
Julia E. Rhine
      Denver, Colorado

Attorneys for Amicus Curiae Colorado League of Women Voters:
Law Offices of Angelique Layton Anderson
Angelique Layton Anderson
     Louisville, Colorado

Attorneys for Amicus Curiae Colorado Oil & Gas Association:
Brownstein Hyatt Farber Schreck, LLP
Mark J. Mathews
     Denver, Colorado
Attorneys for Amici Curiae Colorado PTA, Together Against Neighborhood Drilling,
Dr. Stephanie Malin, Stacia Ryder, Shirley Smithson, and Ulrike Webster:
Berg Hill Greenleaf Ruscitti LLP
Rudy E. Verner
Megan Gutwein
     Boulder, Colorado

Attorneys for Amicus Curiae League of Oil and Gas Impacted Coloradans:
Chiropolos Law
Mike Chiropolos
     Boulder, Colorado

Attorneys for Amici Curiae Local Governments:
Boulder County
David Hughes, Deputy County Attorney
Katherine A. Burke, Senior Assistant County Attorney
     Boulder, Colorado

City of Boulder
Thomas A. Carr, City Attorney
     Boulder, Colorado


                                         3
City and County of Broomfield
Patricia W. Gilbert, City and County Attorney
      Broomfield, Colorado

City of Commerce City
Robert D. Sheesley, City Attorney
     Commerce City, Colorado

Eagle County
Bryan Treu, Eagle County Attorney
     Eagle, Colorado

Town of Erie
Hoffmann, Parker, Wilson, & Carberry, P.C.
Kendra L. Carberry
Evin B. King
     Denver, Colorado

City of Fort Collins
Carrie Mineart Daggett, City Attorney
     Fort Collins, Colorado
Gunnison County
David Baumgarten, Gunnison County Attorney
Matthew Hoyt, Assistant County Attorney
     Gunnison, Colorado

City of Lafayette
Williamson & Hayashi, LLC
David S. Williamson
     Boulder, Colorado

City of Longmont
Daniel Kramer, Assistant City Attorney
     Longmont, Colorado

City of Louisville
Light Kelly P.C.
Samuel J. Light
     Denver, Colorado

Pitkin County
John Ely, Pitkin County Attorney
      Aspen, Colorado

                                          4
San Miguel County
Amy T. Markwell, San Miguel County Attorney
     Telluride, Colorado

Summit County
Jeffrey L. Huntley, Summit County Attorney
      Breckenridge, Colorado

City of Westminster
David Frankel, City Attorney
     Westminster, Colorado

Attorney for Amicus Curiae Mountain States Legal Foundation:
Cody J. Wisniewski
     Lakewood, Colorado

Attorneys for Amici Curiae The National Association of Manufacturers, the National
Federation of Independent Business Small Business Legal Center, the Colorado
Association of Commerce & Industry, and the Independent Petroleum Association of
America:
Lewis Bess Williams and Weese P.C.
Ezekiel J. Williams
Carlos R. Romo
     Denver, Colorado

Attorney for Amicus Curiae Northwest Colorado Council of Governments
Torie Jarvis
     Silverthorne, Colorado

Attorneys for Amici Curiae Our Health, Our Future, Our Longmont; Sierra Club;
Earthworks; Food & Water Watch; Conservation Colorado; Weld Air & Water; and
Wall of Women:
Environmental Law Clinic, University of Denver Sturm College of Law
Timothy Estep
Kevin Lynch
     Denver, Colorado




                                        5
Attorneys for Amici Curiae 350 Colorado; Be the Change; Broomfield Clean Air and
Water; Broomfield Moms Active Community; Center for Biological Diversity;
Citizens for a Healthy Community; Citizens for Huerfano County; Clean Energy
Action; Colorado Rising; Earth Guardians; Eco-Justice Ministries; Erie Protectors;
Front Range Residents for Environment, Safety and Health; Loretto Earth Network;
North Range Concerned Citizens; Northern Colorado Community Rights Network;
Our Health, Our Future, Our Longmont; Protect Our Loveland; Transition Fort
Collins; and Wall of Women Colorado:
Western Environmental Law Center
Kyle Tisdel
     Taos, New Mexico

Attorneys for Amicus Curiae Vital for Colorado:
Holland & Hart LLP
Stephen G. Masciocchi
     Denver, Colorado

Robinson, Waters & O’Dorisio PC
Peter T. Moore
Kimberly Bruetsch
     Denver Colorado




JUSTICE GABRIEL delivered the Opinion of the Court.

                                         6
¶1     Respondents Xiuhtezcatl Martinez, Itzcuahtli Roske-Martinez, Sonora Brinkley,

Aerielle Deering, Trinity Carter, Jamirah DuHamel, and Emma Bray are youth activists

who have devoted substantial time and effort toward pursuing their goal of protecting

the health of Colorado citizens and Colorado’s environment. The court acknowledges

the civic engagement of these young men and women as well as the concerns that

motivated this action, and nothing in this opinion should be construed as expressing a

view as to the merits of Respondents’ concerns, or, conversely, as to the merits of the

Colorado Oil and Gas Conservation Commission’s (the “Commission’s”) interest in

fostering the responsible, balanced development, production, and utilization of

Colorado’s oil and gas resources.      The resolution of these weighty and sometimes

conflicting policy concerns, however, is not the issue before us. Rather, this case requires

us to decide whether, in accordance with the Colorado Oil and Gas Conservation Act (the

“Act”), section 34-60-102(1)(a)(I), C.R.S. (2018), the Commission properly declined to

engage in rulemaking to consider a rule proposed by Respondents, which we view as a

far narrower question.

¶2     Respondents proposed a rule that, among other things, would have precluded the

Commission from issuing any permits for the drilling of an oil and gas well “unless the

best available science demonstrates, and an independent, third-party organization

confirms, that drilling can occur in a manner that does not cumulatively, with other

actions, impair Colorado’s atmosphere, water, wildlife, and land resources, does not

adversely impact human health, and does not contribute to climate change.”



                                             7
¶3       After soliciting and receiving public comment and allowing interested parties to

be heard, the Commission declined to engage in rulemaking to consider this proposed

rule because, among other things, (1) the rule would have required the Commission to

readjust the balance purportedly crafted by the General Assembly under the Act and

conditioned new oil and gas drilling on a finding of no cumulative adverse impacts, both

of which the Commission believed to be beyond its statutory authority, and (2) the

Commission was already working with the Colorado Department of Public Health and

Environment (“CDPHE”) to address the concerns to which the rule was directed and

other Commission priorities took precedence over the proposed rulemaking at this time.

¶4       Respondents challenged the Commission’s ruling in the Denver District Court, but

that court ultimately upheld the Commission’s decision. Respondents appealed, and, in

a split, published decision, a division of the court of appeals reversed the district court’s

order. Martinez v. Colo. Oil & Gas Conservation Comm’n, 2017 COA 37, __ P.3d __. We then

granted certiorari.1

¶5       We now conclude, contrary to the division majority below, that the Commission

properly declined to engage in rulemaking to consider Respondents’ proposed rule. We




1   We granted certiorari to review the following issue:
         Whether the Court of Appeals erred in determining that the Colorado Oil
         and    Gas      Conservation      Commission     misinterpreted     section
         34-60-102(1)(a)(I) as requiring a balance between oil and gas development
         and public health, safety, and welfare.



                                              8
reach this conclusion for three primary reasons. First, our review of an administrative

agency’s decision as to whether to engage in rulemaking is limited and highly deferential.

Second, in our view, the Commission correctly determined that, under the applicable

language of the Act, it could not properly adopt the rule proposed by Respondents.

Specifically, as the Commission recognized, the pertinent provisions do not allow it to

condition all new oil and gas development on a finding of no cumulative adverse impacts

to public health and the environment.       Rather, the provisions make clear that the

Commission is required (1) to foster the development of oil and gas resources, protecting

and enforcing the rights of owners and producers, and (2) in doing so, to prevent and

mitigate significant adverse environmental impacts to the extent necessary to protect

public health, safety, and welfare, but only after taking into consideration

cost-effectiveness and technical feasibility. Finally, in declining to engage in rulemaking,

the Commission reasonably relied on the facts that it was already working with the

CDPHE to address the concerns underlying Respondents’ proposed rule and that other

Commission priorities took precedence at this time.

¶6     Accordingly, we reverse the judgment of the division below.

                           I. Facts and Procedural History

¶7     In 2013, Respondents petitioned the Commission to promulgate a rule providing,

as pertinent here, that

       [t]he Commission shall not issue any permits for the drilling of a well for
       oil and gas unless the best available science demonstrates, and an
       independent, third-party organization confirms, that drilling can occur in a
       manner that does not cumulatively, with other actions, impair Colorado’s


                                             9
      atmosphere, water, wildlife, and land resources, does not adversely impact
      human health, and does not contribute to climate change.

¶8    In support of their petition, Respondents asserted, among other things, that

“hydraulic fracturing is adversely impacting human health,” as well as impairing

“Colorado’s atmosphere, water, soil, and wildlife resources,” and that “[t]he science

unequivocally shows that anthropogenic climate change is occurring and is threatening

the stability of the global climate.” The petition further claimed that “[t]he Public Trust

Doctrine demands that Colorado act to preserve the atmosphere and provide a livable

future for present and future generations of Colorado residents.”

¶9    After receiving the Petition, the Commission solicited written comments from

interested persons and parties, held a public hearing at which numerous parties testified

for and against the proposed rule, and then engaged in deliberations based on the over

1,100-page administrative record that had been created as a result of this process.

Ultimately, by unanimous vote, the Commissioners issued a written order declining to

engage in rulemaking to consider adopting Respondents’ proposed rule. In so ruling, the

Commission found and concluded, as pertinent here, that (1) “[t]he Proposed Rule, if

adopted, would have required the Commission to readjust the balance crafted by the

General Assembly under the Act, and is therefore beyond the Commission’s limited grant

of statutory authority”; (2) “the Proposed Rule hinges on conditioning new oil and gas

drilling on a finding of no cumulative adverse impacts, which is beyond the

Commission’s limited statutory authority”; (3) Colorado courts have expressly rejected

the public trust doctrine; (4) “[t]he Commission, in cooperation with the [CDPHE] is


                                            10
currently addressing many of the concerns in the Petition”; (5) “[m]ost, if not all, of the

relief sought in the Petition related to air quality is within CDPHE’s jurisdiction, and not

[the Commission’s] jurisdiction”; and (6) “[t]here are other Commission priorities that

must take precedence over the proposed rulemaking at this time.”

¶10    Respondents challenged the Commission’s order in the Denver District Court,

after which the American Petroleum Institute and the Colorado Petroleum Association

intervened as defendants. As pertinent here, Respondents argued in the district court

that the Commission’s order was arbitrary and capricious, an abuse of discretion, and

otherwise contrary to law. In doing so, Respondents principally relied on the first

subsection of the Act’s legislative declaration, which states that it is in the public interest

to

       [f]oster the responsible, balanced development, production, and utilization
       of the natural resources of oil and gas in the state of Colorado in a manner
       consistent with protection of public health, safety, and welfare, including
       protection of the environment and wildlife resources.

§ 34-60-102(1)(a)(I) (emphasis added).       According to Respondents, “in a manner

consistent with” indicates that the General Assembly “set out a mandatory condition that

must be satisfied,” rather than a balancing test, as Respondents read the Commission’s

order to require.

¶11    The district court ultimately disagreed and, applying the two-part test articulated

in Chevron, U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 842–43

(1984), concluded that the pertinent statutory language is clear and requires the




                                              11
Commission to “strike a balance between the regulation of oil and gas operations and

protecting public health, the environment, and wildlife resources.”

¶12    Respondents then appealed the district court’s order, and, in a split, published

decision, a division of the court of appeals agreed that the Act’s plain language is clear

and unambiguous but concluded that this language “supports a conclusion different

from that reached by the Commission and the district court.” Martinez, ¶ 19. Specifically,

in the majority’s view, “in a manner consistent with” protection of public health, safety,

and welfare did not indicate a balancing test weighing public health, safety, and welfare

against oil and gas production. Id. at ¶¶ 17, 21. Rather, “in a manner consistent with”

indicated “a condition that must be fulfilled.” Id. at ¶ 21.

¶13    In support of this conclusion, the majority opined that the term “balanced” in

section 34-60-102(1)(a)(I) relates to and modifies “development, production, and

utilization” but does not affect the remaining provisions in that section, including the

language relating to public health, safety, and welfare. Id. at ¶ 20. The majority further

observed that numerous Colorado cases use the phrase “in a manner consistent with” to

mean “subject to,” rather than “balanced with.” Id. at ¶¶ 22–24. And the majority stated

that the Act’s legislative history reveals the legislature’s “general movement away from

unfettered oil and gas production and [its] incorporation of public health, safety, and

welfare as a check on that development.” Id. at ¶ 30.

¶14    Judge Booras dissented. She began by noting that the language, “in a manner

consistent with,” appears in the Act’s legislative declaration and that this language

therefore could be used only to interpret an ambiguous statute; it could not override the

                                             12
Act’s operative language. Id. at ¶ 41 (Booras, J., dissenting). She then explained that the

“actual authority” of the Commission to regulate oil and gas is set out in section

34-60-106(2)(d), C.R.S. (2018), which provides that the Commission is authorized to

regulate oil and gas operations

       so as to prevent and mitigate significant adverse environmental impacts on
       any air, water, soil, or biological resource resulting from oil and gas
       operations to the extent necessary to protect public health, safety, and
       welfare, including protection of the environment and wildlife resources,
       taking into consideration cost-effectiveness and technical feasibility.

Id. at ¶ 42. In Judge Booras’s view, the fact that the Act instructs the Commission to

consider cost-effectiveness and technical feasibility suggests that the protection of public

health, safety, and welfare is not, by itself, a determinative consideration. Id. at ¶ 43.

¶15    The Commission and Intervenors independently petitioned this court to review

the division’s decision.    Respondents opposed the petitions, the Commission and

Intervenors filed reply briefs, and numerous parties filed amicus briefs. We granted

review.

                                       II. Analysis

¶16    We begin by setting forth the applicable standard of review and principles of

statutory construction.    We then discuss the pertinent provisions of the Act, and,

perceiving those provisions to be ambiguous, we proceed to construe them. We end by

considering, in light of our statutory construction, whether the Commission properly

declined to engage in rulemaking to consider Respondents’ proposed rule, and we

conclude that it did.



                                             13
        A. Standard of Review and Principles of Statutory Construction

¶17    We review an agency’s refusal to engage in rulemaking under Colorado’s

Administrative Procedure Act, section 24-4-106(7)(b), C.R.S. (2018). This statute requires

us to hold unlawful and set aside agency actions found to be, among other things,

arbitrary or capricious; in excess of statutory jurisdiction, authority, purposes, or

limitations; an abuse of discretion; unsupported by substantial evidence when the record

is considered as a whole; or otherwise contrary to law. Id.

¶18    An agency has broad discretion to decide whether to engage in rulemaking, and,

thus, our review of its decision as to whether to do so is “‘extremely limited’ and ‘highly

deferential.’” Massachusetts v. EPA, 549 U.S. 497, 527–28 (2007) (quoting Nat’l Customs

Brokers & Forwarders Ass’n. of Am., Inc. v. United States, 883 F.2d 93, 96 (D.C. Cir. 1989));

see also Nat’l Mining Ass’n v. Mine Safety & Health Admin., 599 F.3d 662, 667 (D.C. Cir. 2010)

(“‘[A]n agency’s refusal to institute rulemaking proceedings is at the high end of the

range’ of levels of deference we give to agency action under our ‘arbitrary and capricious’

review.”) (quoting Defenders of Wildlife v. Gutierrez, 532 F.3d 913, 919 (D.C. Cir. 2008));

WildEarth Guardians v. Salazar, 741 F. Supp. 2d 89, 103 (D.D.C. 2010) (explaining that an

agency’s refusal to promulgate a rule “is to be overturned only in the rarest and most

compelling of circumstances . . . which have primarily involved plain errors of law,

suggesting that the agency has been blind to the source of its delegated power”) (quoting

Am. Horse Prot. Ass’n v. Lyng, 812 F.2d 1, 5 (D.C. Cir. 1987)). One of the main purposes of

limitations such as these is “to avoid judicial entanglement in abstract policy



                                             14
disagreements which courts lack both expertise and information to resolve.” Norton v.

S. Utah Wilderness All., 542 U.S. 55, 66 (2004).

¶19    We review issues of statutory interpretation de novo. UMB Bank, N.A. v. Landmark

Towers Ass’n, 2017 CO 107, ¶ 22, 408 P.3d 836, 840. In doing so, we look to the entire

statutory scheme in order to give consistent, harmonious, and sensible effect to all of its

parts, and we apply words and phrases in accordance with their plain and ordinary

meanings. Id. When the statutory language is clear, we apply it as written and need not

resort to other rules of statutory construction. Id. When, however, the statutory language

is ambiguous, we may examine the legislative intent, the circumstances surrounding the

statute’s adoption, and the possible consequences of different interpretations to

determine the proper construction of the statute. Coffman v. Williamson, 2015 CO 35, ¶ 23,

348 P.3d 929, 936. A statute is ambiguous when it is reasonably susceptible of multiple

interpretations. Id.

                          B. Applicable Provisions of the Act

¶20    Section 34-60-102(1) sets forth the Act’s legislative declaration and provides, in

pertinent part:

       (1)(a) It is declared to be in the public interest to:

       (I) Foster the responsible, balanced development, production, and
       utilization of the natural resources of oil and gas in the state of Colorado in
       a manner consistent with protection of public health, safety, and welfare,
       including protection of the environment and wildlife resources;

       (II) Protect the public and private interests against waste in the production
       and utilization of oil and gas;



                                               15
      (III) Safeguard, protect, and enforce the coequal and correlative rights of
      owners and producers in a common source or pool of oil and gas . . . ;

      (IV) Plan and manage oil and gas operations in a manner that balances
      development with wildlife conservation . . . ;

      (b) . . . It is the intent and purpose of this article to permit each oil and gas
      pool in Colorado to produce up to its maximum efficient rate of production,
      subject to the prevention of waste, consistent with the protection of public
      health, safety, and welfare, including protection of the environment and
      wildlife resources, and subject further to the enforcement and protection of
      the coequal and correlative rights of the owners and producers of a
      common source of oil and gas . . . .

¶21   Section 34-60-105(1), C.R.S. (2018), provides the Commission with “the power to

make and enforce rules, regulations, and orders pursuant to this article, and to do

whatever may reasonably be necessary to carry out the provisions of this article.”

¶22   Section 34-60-106(2)(d), in turn, sets forth additional powers of the Commission,

including, as pertinent here, the power to regulate

      [o]il and gas operations so as to prevent and mitigate significant adverse
      environmental impacts on any air, water, soil, or biological resource
      resulting from oil and gas operations to the extent necessary to protect
      public health, safety, and welfare, including protection of the environment
      and wildlife resources, taking into consideration cost-effectiveness and
      technical feasibility.

¶23   Petitioners assert that the foregoing statutory language makes clear that the

Commission must balance oil and gas development with the protection of public health

and the environment. They emphasize that the words “in a manner consistent with” in

the legislative declaration cannot override the Act’s substantive provisions, which,

petitioners say, unambiguously require a balanced regulatory approach and command

the Commission to pursue a number of different policy goals, including both the


                                             16
production, development, and utilization of oil and gas resources and the protection of

public health and the environment.

¶24    Petitioners further contend that even if it were proper to focus exclusively on the

legislative declaration, “consistent with” cannot mean the same as “subject to” because it

would effectively re-write section 34-60-102(1)(b), which uses both phrases in the same

sentence:

       (b) . . . It is the intent and purpose of this article to permit each oil and gas
       pool in Colorado to produce up to its maximum efficient rate of production,
       subject to the prevention of waste, consistent with the protection of public
       health, safety, and welfare, including protection of the environment and
       wildlife resources, and subject further to the enforcement and protection of
       the coequal and correlative rights of the owners and producers of a
       common source of oil and gas . . . .

(Emphases added.)

¶25    And Petitioners contend that the construction adopted by the division majority

below arguably ignores other provisions of the Act, as well as the Act’s legislative history,

which Petitioners assert shows that the Act aims, at least in part, to foster oil and gas

development in this state.

¶26    Respondents reply that the division correctly concluded that the phrase “in a

manner consistent with public health, safety, and welfare” in section 34-60-102(1)(a)(I)

does not indicate a balancing test but rather establishes a condition that must be fulfilled.

See Martinez, ¶ 21. In support of this argument, Respondents first point out that the

words “responsible, balanced” relate to and modify the immediately following nouns,

namely, “development, production, and utilization,” but not any subsequent words in

the section. Thus, “responsible” and “balanced” do not indicate a balancing of oil and

                                              17
gas development against public health. Rather, those words refer to the development,

production, and utilization of oil and gas in a manner that does not waste those resources

and that protects correlative rights.

¶27    Respondents further assert that, contrary to Petitioners’ contentions, the legislative

declaration provides the Commission “an uncontroverted mandate to regulate oil and

gas development and operations in a certain manner” and “[t]he substantive provisions

of the Act give the Commission the statutory authority to effectuate that mandate.”

¶28    Finally, Respondents assert that (1) other portions of the Act support a

construction that mandates protection of public health, safety, and welfare;

(2) interpreting “consistent with” to mean “subject to” does not re-write portions of the

Act because both phrases merely indicate conditions that must be fulfilled; and (3) the

division majority’s interpretation of the Act is consistent with other cases interpreting the

Act.

¶29    In our view, the above-quoted statutory language is reasonably susceptible of the

interpretations proffered by both Petitioners and Respondents in this case, a conclusion

that we believe to be supported by the fact that the district court and Judge Booras agreed

with Petitioners’ interpretation while the division majority below agreed with

Respondents’ interpretation (notwithstanding the fact that all of those jurists believed

that their respective interpretations were supported by the Act’s unambiguous

language).

¶30    Because we believe that the applicable statutory language is reasonably

susceptible of multiple interpretations, we conclude that that language is ambiguous. See

                                             18
Coffman, ¶ 23, 348 P.3d at 936. We thus turn to other tools of statutory construction,

including the Act’s statutory and legislative history, to aid us in interpreting the Act’s

pertinent provisions. See id.2

                  C. History of the Act and Statutory Construction

¶31    The statutory history of the Act informs our understanding of legislative intent

here. The General Assembly first passed the Act in 1951 to “defin[e] and prohibit[] the

waste of oil and gas in the state of Colorado” and to establish and set forth the authority

of the Commission. Ch. 230, 1951 Colo. Sess. Laws 651, 651.

¶32    In 1955, the General Assembly added a declaration of purpose, and, for the next

three decades, the Act’s primary policy goal was to “foster, encourage and promote the

development, production and utilization of the natural resources of oil and gas in the

state of Colorado.” Ch. 208, sec. 10, § 100-6-22, 1955 Colo. Sess. Laws 648, 657.

¶33    In 1985, the General Assembly amended the Act and for the first time expressly

addressed concerns regarding public health, safety, and welfare.              Ch. 272, sec. 1,




2 For purposes here, we use “statutory history” to refer to the evolution of a statute as it
is amended over time by the legislature and “legislative history” to refer to the
development of a statute during the legislative process and prior to enactment or
amendment. “Legislative history” thus encompasses, for example, bill drafts and bill
sponsor comments. By examining the statutory history of the Act as we proceed to do
below, we do not mean to suggest that we necessarily must deem a statute ambiguous
before considering its statutory history. See, e.g., Denver Publ’g Co. v. Bd. of Cty. Comm’rs,
121 P.3d 190, 197–98 (Colo. 2005) (examining the statutory history of the Colorado Open
Records Act without declaring it to be ambiguous); see also Powerex Corp. v. Reliant Energy
Servs., Inc., 551 U.S. 224, 231 (2007) (relying on the statutory history of 28 U.S.C. § 1447 to
assist in its interpretation without declaring that provision to be ambiguous).

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§ 34-60-106(10)–(11), 1985 Colo. Sess. Laws 1129, 1129. Specifically, at that time, the

legislature authorized the Commission to promulgate rules and regulations to protect the

health, safety, and welfare of any person at an oil and gas well and of the general public

in the drilling, completion, and operation of oil and gas wells and production facilities.

Id. The legislature did not, however, alter any of its previously established legislative

purposes.

¶34     The legislature again noted the importance of public health, safety, and welfare

when it amended the Act in 1994, to add that it is in the public interest to foster,

encourage, and promote the development, production, and utilization of the natural

resources of oil and gas in Colorado “in a manner consistent with protection of public

health, safety, and welfare.” Ch. 317, sec. 2, § 34-60-102(1), 1994 Colo. Sess. Laws 1978,

1978.

¶35     And the legislature expressed its concern for public health, safety, and welfare

when it amended the Act in 2007, to include “protection of the environment and wildlife

resources” as a component of public health, safety, and welfare.              Ch. 320, sec. 2,

§ 34-60-102(1), 2007 Colo. Sess. Laws 1357, 1357. Notably, in 2007, the legislature also

amended subsection 34-60-102(1)(a)(I)’s language to note that it is in the public interest

to “foster the responsible, balanced development” of oil and gas.             Ch. 320, sec. 2,

§ 34-60-102(1), 2007 Colo. Sess. Laws 1357, 1357 (emphasis added).

¶36     Unlike the division majority below, we do not read this lengthy statutory history

as reflecting a legislative intention to establish the protection of public health, safety, and

welfare as a check on oil and gas development. Nor do we perceive in this history an

                                              20
intention to condition further oil and gas development on a finding of no cumulative

adverse impacts to public health or the environment. Rather, we view this history as

reflecting a legislative intent to promote multiple policy objectives, including the

continued development of oil and gas resources and the protection of public health and

the environment, without conditioning one policy objective on the satisfaction of any

other.

¶37      Our view in this regard finds substantial support in the legislative history of the

Act, and particularly in the testimony of the representatives who sponsored and

introduced the legislative bills that added health, safety, and welfare concerns to the Act’s

legislative declaration. See Vensor v. People, 151 P.3d 1274, 1279 (Colo. 2007) (“While by

no means conclusive, the testimony of a bill’s sponsor concerning its purpose and

anticipated effect can be powerful evidence of legislative intent.”).

¶38      For example, in introducing to the Agriculture, Natural Resources, and Energy

Committee the bill that added the language “in a manner consistent with” to the Act’s

legislative declaration, Representative Jerke explained that the added language

         gets us a long way in the direction that I think that we need to go in making
         sure that the oil industry can still operate in an economical manner. We’re
         not putting them out of business through this. We’re taking far, far better
         care of our land, our water, even our air as a result of this legislation.

Hearings on S.B. 94-177 before the Agric., Nat. Res., and Energy Comm., 64th Gen.

Assemb., 2d Sess. (Mar. 24, 1994) (statement of Rep. Jerke).

¶39      Similarly, when Representative Jerke introduced the Bill to the House, he

explained that the Commission “will indeed have the ability to foster, encourage, and


                                              21
promote the development and production and utilization of oil and gas . . . . [W]e’re

giving them the ability not just to advance the industry, as they’ve done in the past, but

to also deal with public health, safety, welfare, those kinds of issues.” Hearings on

S.B. 94-177 before the House, 64th Gen. Assemb., 2d Sess. (Apr. 26, 1994) (statement of

Rep. Jerke).

¶40    And when Representative Curry introduced the House Bill that added “protection

of the environment and wildlife resources” to section 34-60-102(1)(a)(I), she explained:

       Energy development can occur in a manner that minimizes adverse impact
       to the public health and environment. In fact, it is. Certain operators are
       taking aggressive steps to make sure that we are protecting those other
       values. It does not have to be a zero-sum game with the winner taking all.
       We need a regulatory framework, however, that will provide a mechanism
       for considering these other impacts, both positive and negative.

Hearings on H.B. 07-1341 before the H. Agric. Comm., 66th Gen. Assemb., 1st Sess.

(Mar. 14, 2007) (statement of Rep. Curry).

¶41    Reading the above-quoted portions of the Act in light of this legislative history and

in the context of the Act as a whole leads us to conclude that these provisions do not allow

the Commission to condition all new oil and gas development on a finding of no

cumulative adverse impacts to public health and the environment, as Respondents assert

the Commission must do. Nor do we perceive the statutory language as creating a

balancing test by which the public’s interest in oil and gas development is weighed

against its interest in public health and the environment, as Petitioners seem to suggest.

Rather, in our view, the pertinent provisions make clear that the Commission is required

(1) to foster the development of oil and gas resources, protecting and enforcing the rights


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of owners and producers, and (2) in doing so, to prevent and mitigate significant adverse

environmental impacts to the extent necessary to protect public health, safety, and

welfare, but only after taking into consideration cost-effectiveness and technical

feasibility. We reach this conclusion for several reasons.

¶42    First, sections 34-60-105(1) and 34-60-106(2)(d) provide the Commission with

authority to regulate public health, safety, welfare, and environmental concerns as an

important component of its role in overseeing oil and gas development. Hence, section

34-60-106(2)(d) authorizes the Commission to regulate oil and gas operations so as to

avoid “and mitigate significant” adverse environmental impacts to the extent necessary to

protect public health, safety, and welfare, “taking into consideration cost-effectiveness and

technical feasibility.” Id. (emphases added). In our view, this statutory language envisions

some possible environmental and public health risks. Had the legislature intended to

preclude any cumulative adverse impacts, as Respondents claim, the statute would not

have included the language “and mitigate significant” or “taking into consideration

cost-effectiveness and technical feasibility.” Rather, the provision would have required

the Commission to regulate oil and gas operations so as to avoid adverse environmental

impacts on any air, water, soil, or biological resource, to the extent necessary to protect

public health, safety, and welfare, including protection of the environment and wildlife

resources.

¶43    Second, the Act’s legislative declaration, when read as a whole, evinces the

General Assembly’s intent that the Commission pursue multiple policy goals and not

condition one legislative objective on the satisfaction of another. As explained above, the

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declaration begins by stating that it is in the public interest to “[f]oster the responsible,

balanced development, production, and utilization of the natural resources of oil and gas

in the state of Colorado in a manner consistent with protection of public health, safety,

and welfare, including protection of the environment and wildlife resources.”

§ 34-60-102(1)(a)(I). But this is not the only policy goal set forth in that section. The

declaration also directs the Commission to (1) “[p]rotect the public and private interests

against waste in the production and utilization of oil and gas”; (2) “[s]afeguard, protect,

and enforce the coequal and correlative rights of owners and producers in a common

source or pool of oil and gas”; (3) “[p]lan and manage oil and gas operations in a manner

that balances development with wildlife conservation”; and (4) “permit each oil and gas

pool in Colorado to produce up to its maximum efficient rate of production, subject to

the prevention of waste, consistent with the protection of public health, safety, and

welfare.” § 34-60-102(1).

¶44    Third, the above-described legislative history, and particularly the testimony of

the legislators who sponsored the bills adding the words “in a manner consistent with”

and “protection of the environment and wildlife resources” to the legislative declaration,

makes clear that, in adding this language, the legislature’s intent was not to create a

condition precedent to further oil and gas development. Rather, its intent was to

minimize adverse impacts to public health and the environment while at the same time




                                             24
ensuring that oil and gas development, production, and utilization could proceed in an

economical manner.3

                        D. The Current Rulemaking Petition

¶45    Against this background, we turn to the ultimate question before us, namely,

whether the Commission properly declined to engage in rulemaking to consider the rule

proposed by Respondents.

¶46    As noted above, the Commission declined to engage in rulemaking because,

among other things, (1) it believed that adopting the rule proposed by Respondents

would be beyond the Commission’s statutory authority and (2) it was already working

with the CDPHE to address the concerns to which the proposed rule was directed and

other Commission priorities took precedence at this time. In our view, the Commission’s

decision was well within its discretion.

¶47    With respect to the Commission’s understanding of its authority, we note, as an

initial matter, that the briefing in this case sometimes conflates the terms “authority” and

“jurisdiction.” We, however, do not read the Commission’s order as concluding that it

lacked subject matter jurisdiction to consider Respondents’ proposed rule. Rather, we




3 In reaching this conclusion, we hasten to add that we do not intend to decide here the
full range or limits of the Commission’s statutory authority. Rather, we decide only the
issues that the parties have presented to us, namely, (1) the proper construction of the
Act’s legislative declaration and (2) whether, in light of that construction and the
deference due to an administrative agency’s decision as to whether to engage in
rulemaking, the Commission properly declined to engage in rulemaking to consider the
proposed rule at issue in this case.

                                            25
understand the Commission’s focus to have been on whether, consistent with its

statutory mandate, it could adopt the rule proposed by Respondents.

¶48    With that understanding, we cannot say that the Commission’s decision to decline

to engage in rulemaking to consider Respondents’ proposed rule was arbitrary or

capricious; in excess of statutory jurisdiction, authority, purposes, or limitations; an abuse

of discretion; unsupported by substantial evidence when the record is considered as a

whole; or otherwise contrary to law. See § 24-4-106(7)(b).

¶49    As previously noted, Respondents’ proposed rule would have precluded new oil

and gas development unless it could occur “in a manner that does not cumulatively, with

other actions, impair Colorado’s atmosphere, water, wildlife, and land resources, does

not adversely impact human health, and does not contribute to climate change.”

¶50    In light of our above-described construction of the pertinent provisions of the Act,

we conclude that the Commission correctly determined that it could not, consistent with

those provisions, adopt such a rule. Specifically, as set forth above, we do not believe

that the pertinent provisions of the Act allow the Commission to condition one legislative

priority (here, oil and gas development) on another (here, the protection of public health

and the environment). Accordingly, in our view, the Commission properly exercised its

discretion in declining to engage in rulemaking to consider Respondents’ proposed rule.

¶51    But this was not the sole basis for the Commission’s decision. Equally significant,

the Commission declined to engage in rulemaking because it was already working with

the CDPHE to address many of the concerns implicated by Respondents’ petition and



                                             26
other regulatory priorities took precedence at this time. In our view, the Commission

again acted within its discretion in making such a decision.

¶52    Here, the Commission’s finding that the issues implicated by Respondents’

petition are being addressed elsewhere is amply supported by the record, and this is

precisely the kind of agency action to which courts owe deference. See Massachusetts,

549 U.S. at 527 (noting that “an agency has broad discretion to choose how best to marshal

its limited resources and personnel to carry out its delegated responsibilities”); see also

Compassion Over Killing v. FDA, 849 F.3d 849, 857 (9th Cir. 2017) (“[T]he agency’s decision

to prioritize other projects is entitled to great deference by a reviewing court.”); Simpson v.

Cotton Creek Circles, LLC, 181 P.3d 252, 261 (Colo. 2008) (noting that “courts defer to policy

determinations in rule-making proceedings”). This is particularly true in this case, where

the Commission specifically indicated that it was collaborating with the CDPHE to

address the matters implicated by Respondents’ proposed rule and where the

Commission noted, with record support, that other priorities took precedence over the

proposed rulemaking.

¶53    Because the Commission’s decision to decline to conduct a rulemaking proceeding

to consider Respondent’s proposed rule was based on a correct understanding of the

Commission’s statutory charge and on an amply supported finding as to the proper use

of the Commission’s resources, we perceive no abuse of discretion in the Commission’s

decision to decline to engage in rulemaking to consider the specific rule at issue here.




                                              27
                                    III. Conclusion

¶54   Because the Commission’s decision to decline to engage in rulemaking to consider

Respondents’ proposed rule was consistent with the applicable provisions of the Act and

with the Commission’s authority to decide how best to marshal its resources to carry out

its statutory duties, we perceive no abuse of discretion in that decision. Accordingly, we

reverse the judgment of the division below.




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