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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
2

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
3

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
4

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 
5

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
6

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.
7

¶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.”
8

¶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.
9

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 
10

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 
11

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 
12

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 
13

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.
14

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 
15

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;
16

(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 
17

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 
18

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
19

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).
20

§ 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 
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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 
22

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 
23

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 
25

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.
26

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 
27

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.
28

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.