PUBLISH

UNITED STATES COURT OF APPEALS

TENTH CIRCUIT 

 

COLORADO DEPARTMENT OF 

PUBLIC HEALTH AND 

ENVIRONMENT, HAZARDOUS 

MATERIALS AND WASTE 

MANAGEMENT DIVISION, 

 Plaintiff - Appellant, 

v. 

UNITED STATES OF AMERICA, 

UNITED STATES DEPARTMENT OF 

DEFENSE, LEON E. PANETTA, as 

United States Secretary of Defense, 

FRANK KENDALL, Under Secretary of 

Defense for Acquisition, Technology and 

Logistics, ASSEMBLED CHEMICAL 

WEAPONS ALTERNATIVES 

PROGRAM, CONRAD F. WHYNE, as 

Acting Program Manager of Assembled 

Chemical Weapons Alternatives Program, 

UNITED STATES DEPARTMENT OF 

THE ARMY PUEBLO CHEMICAL 

DEPOT, TIMOTHY M. GREENHAW, 

Lieutenant Colonel, as Commander of 

United States Department of the Army 

Pueblo Chemical Depot, 

Defendants - Appellees. 

 No. 09-1554 

FILED 

United States Court of Appeals 

Tenth Circuit 

September 5, 2012

Elisabeth A. Shumaker 

Clerk of Court
2 

 

Appeal from the United States District Court 

 for the District of Colorado 

(D.C. No. 1:08-CV-01883-RPM)1

 

David E. Kreutzer, First Assistant Attorney General (John W. Suthers, Attorney General, 

Daniel D. Domenico, Solicitor General, Richard E. Lotz, Assistant Attorney General, 

with him on the briefs), Denver, Colorado for Plaintiff-Appellant. 

Maggie B. Smith (Ignacia S. Moreno, Assistant Attorney General, Lisa E. Jones, Alan D. 

Greenberg, Sambhav N. Sankar, with her on the brief), United States Department of 

Justice, Washington D.C. for Defendants-Appellees. 

 

Before LUCERO, EBEL, and HARTZ, Circuit Judges. 

EBEL, Circuit Judge. 

 

 Since the 1950s, the United States has stored chemical weapons at the Army’s 

weapons depot located near Pueblo, Colorado (“Depot”). Congress has now mandated 

that the Army destroy those weapons by 2017. Separately, Congress authorized the State 

of Colorado to regulate hazardous waste in that state. Invoking that regulatory authority, 

Plaintiff-Appellant Colorado Department of Public Health and Environment, Hazardous 

Materials and Waste Management Division (“Colorado” or “CDPHE”), has declared the 

chemical weapons stored at the Depot awaiting destruction to be hazardous waste. In this 

 

1

 Pursuant to Fed. R. App. P. 43(c), Secretary of Defense Leon E. Panetta is substituted as 

a defendant for former Secretary Robert M. Gates, Under Secretary of Defense Frank 

Kendall is substituted for former Under Secretary John J. Young, Jr., Assembled 

Chemical Weapons Alternatives Program Manager Conrad F. Whyne is substituted for 

former manager Kevin Flamm, and Lieutenant Colonel Timothy M. Greenhaw is 

substituted for Lieutenant Colonel Robert Wittig. 
3 

action, Colorado seeks to enforce against the Depot Colorado’s regulation prohibiting 

storage of any hazardous waste. 

The specific question presented by this appeal is whether Congress’s mandate that 

the Army destroy these chemical weapons at the Depot by 2017 preempts Colorado’s 

enforcement against the Depot of its regulation prohibiting storage of any hazardous 

waste. This case thus lies at the intersection of congressional mandates that, under these 

circumstances, support opposing positions. Based on the fact that Congress 1) delegated 

to Colorado the authority to regulate hazardous waste, so long as the State’s regulations 

are at least as stringent as federal hazardous waste regulations, and 2) required federal 

agencies to follow such state hazardous waste regulation, Colorado argues that the United 

States, in operating the Depot, must comply with the State’s prohibition against storing 

hazardous waste. Based instead on the fact that Congress mandated that the Army 

destroy the chemical weapons at the Depot and gave the Army until 2017 to complete 

their destruction, the United States argues it cannot comply with Colorado’s regulation 

prohibiting the storage of any hazardous waste. 

This difficult case requires us, then, to choose between opposing congressional 

mandates. Ultimately we are persuaded by the detailed manner with which Congress has 

addressed and mandated the destruction of the chemical weapons stored at the Depot to 

conclude that that federal law preempts Colorado’s attempt to regulate that destruction 

process by enforcing its prohibition of the storage of hazardous waste against the Depot. 

Therefore, having jurisdiction under 28 U.S.C. § 1291, we AFFIRM the district court’s 

decision to dismiss Colorado’s claims against the United States. 
4 

I. BACKGROUND 

A. Colorado’s federally-derived authority to regulate hazardous waste 

 In 1976, Congress enacted the Resource Conservation and Recovery Act 

(“RCRA”), see 42 U.S.C. §§ 6901-6992k, in part to establish “a comprehensive 

regulatory scheme for the transportation, treatment, and disposal of hazardous wastes.” 

United States v. Magnesium Corp., 616 F.3d 1129, 1131-32 (10th Cir. 2010) (citing 

RCRA’s Subtitle C, codified at 42 U.S.C. §§ 6921-6939f). Congress charged the federal 

Environmental Protection Agency (“EPA”) with administering RCRA. See United States 

v. Power Eng’g Co., 303 F.3d 1232, 1236 (10th Cir. 2002). Nevertheless, a state can 

apply to the EPA “for authorization to administer and enforce its own hazardous waste 

program [so long as] its program is equivalent to the federal program and provides 

adequate enforcement.” Id.; see 42 U.S.C. § 6926(b). 

 Colorado has enacted its own hazardous waste program, see Colorado Hazardous 

Waste Management Act (“CHWMA”), Colo. Rev. Stat. §§ 25-15-301 to -327, and in 

1984, the EPA authorized Colorado “to operate its hazardous waste program in lieu of the 

federal program,” 49 Fed. Reg. 41,036 (Oct. 19, 1984). See also United States v. 

Colorado, 990 F.2d 1565, 1571 (10th Cir. 1993). CDPHE administers Colorado’s 

hazardous waste management program. 

Colorado has promulgated regulations to implement CHWMA. See Colo. Rev. 

Stat. § 25-15-302(2). Most relevant here, 6 Colo. Code Regs. § 268.50, like its federal 

counterparts, see 42 U.S.C. § 6924(j); 40 C.F.R. § 268.50(a)(2), (b), (c), generally 

prohibits the storage of “hazardous wastes” which are restricted from land disposal. 
5 

6 Colo. Code Regs. § 268.50(a).2 

 A state can adopt “more stringent” regulations than federal law requires. 42 

U.S.C. § 6929; see also Colorado, 990 F.2d at 1569. Thus, “RCRA sets a floor, not a 

ceiling, for state regulation of hazardous wastes.” Safety-Kleen, Inc. v. Wyche, 274 F.3d 

846, 863 (4th Cir. 2001) (quotation omitted). Important here, however, a state’s authority 

to enact more stringent hazardous waste regulations does not insulate the state’s 

regulations from federal-law preemption. See Blue Circle Cement, Inc. v. Bd. of Cnty. 

Comm’rs, 27 F.3d 1499, 1504-05 (10th Cir. 1994); ENSCO, Inc. v. Dumas, 807 F.2d 

743, 744-45 (8th Cir. 1986). Therefore, a state’s “more stringent” hazardous waste 

regulation may still be preempted if, for example, it frustrates the purpose or objective of 

a federal law. See Blue Circle Cement, 27 F.3d at 1504-09 (citing cases); ENSCO, 807 

F.2d at 744-45. This conclusion, that federal law can preempt conflicting state hazardous 

waste regulations, is consistent with RCRA’s savings provision, which provides only that 

“[n]othing in this subchapter [referring to RCRA 42 U.S.C. §§ 6901-6992k] shall be 

construed to prohibit any State or political subdivision thereof from imposing any 

requirements, including those for site selection, which are more stringent than those 

 

2

 Section 268.50 permits “[a]n owner/operator of a hazardous waste treatment, storage, or 

disposal facility” to store hazardous wastes which are restricted from land disposal 

“solely for the purpose of” accumulating enough waste “to facilitate proper recovery, 

treatment, or disposal,” and the regulation sets forth parameters and requirements for 

doing so. 6 Colo. Code Regs. § 268.50(a)(2), (b), (c). Here, however, there is no dispute 

that the Depot has already accumulated a sufficient number of chemical weapons to 

permit their “proper recovery, treatment, or disposal,” so storage for that purpose is not at 

issue. 
6 

imposed by [federal] regulations.”3 42 U.S.C. § 6929 (emphasis added). 

Pursuant to the Federal Facilities Compliance Act, the federal government and its 

agencies must comply with an EPA authorized state program regulating hazardous waste, 

such as Colorado’s, “‘to the same extent, as any person . . . .’” Colorado, 990 F.2d at 

1569 (quoting 42 U.S.C. § 6961(a)). The United States has thus waived its sovereign 

immunity from state-imposed permit requirements, as well as conditions imposed by the 

state for the storage, treatment and disposal of hazardous waste. See United States v. 

New Mexico, 32 F.3d 494, 495, 497 (10th Cir. 1994); Colorado, 990 F.2d at 1569 n.4. 

This waiver of sovereign immunity, however, again does not insulate a state regulation 

from federal preemption. 

B. The Pueblo Chemical Depot 

 The Depot is one of several Army installations where the United States stores 

chemical weapons. Currently, the Army is storing “more than 2600 tons of . . . mustard 

agent in mortars and projectile munitions” at the Depot, in ninety-eight “igloos,” which 

are “earthen-covered concrete structures.” (Aplt. App. at 82; Aple. Supp. App. at 36 ¶ 3; 

55 ¶ 3.) Four of these ninety-eight igloos contain leaking chemical weapons and 

“contaminated personal protective equipment.”4

 (Aplt. App. at 83.) The other ninety-

 

3

 State regulation that is more stringent than federal hazardous waste regulations can also 

be preempted by RCRA if the state regulation frustrates Congress’s overall purposes in 

enacting RCRA. See Blue Circle Cement, 27 F.3d at 1504-09 (citing cases). See infra at 

9 & n.5. Congress’s frequent extensions of time to destroy the mustard agent stored at 

the Depot were not incorporated into RCRA. 

4

 Out of the 780,000 munitions stored at the Depot, the Army has found ninety-three to be 

leaking. 
7 

four igloos contain chemical munitions that remain usable as weapons. 

C. Congress’s mandate that the Department of Defense destroy the United States’ 

stockpile of chemical weapons 

In 1985, Congress directed the Secretary of Defense (“Secretary”) to destroy the 

United States’ then-existing stockpile of chemical weapons. 50 U.S.C. § 1521(a). In 

1994, Congress forbade the Secretary from transporting “any chemical munition that 

constitutes part of the chemical weapons stockpile out of the State in which that munition 

[wa]s located on October 5, 1994.” Id. § 1512a(a). Thus, Congress has mandated that 

the Department of Defense (“DOD”) destroy the Depot’s chemical weapons in Colorado. 

Congress further directed the Secretary, in destroying these weapons, to 

provide for-- 

(A) maximum protection for the environment, the general 

public, and the personnel who are involved in the destruction 

of the lethal chemical agents and munitions . . . , including 

but not limited to the use of technologies and procedures that 

will minimize risk to the public at each site; and 

(B) adequate and safe facilities designed solely for the 

destruction of lethal chemical agents and munitions. 

Id. § 1521(d)(1) (2011). 

 In order to comply with Congress’s directive to destroy the United States’ 

chemical weapons, the DOD originally intended to incinerate these weapons. See Chem. 

Weapons Working Grp., Inc. v. U.S. Dep’t of the Army, 111 F.3d 1485, 1487-88 (10th 

Cir. 1997). Before doing so, however, Congress required that the Army conduct testing 

to verify the viability of this method of destruction. See 50 U.S.C. § 1521(k) (1990; 

subsequently amended); see also Chem. Weapons Working Grp., 111 F.3d at 1487-88. 
8 

By 1993, the Army had determined that it could incinerate the chemical weapons. See 

Chem. Weapons Working Grp., 111 F.3d at 1487-88. Several storage sites other than the 

Depot then began the process of building incineration plants and incinerating their stored 

chemical weapons. 

In 1996, however, Congress directed the DOD to explore alternative methods of 

destroying these chemical weapons. After considering available alternatives, the DOD, 

in 2002, decided to “neutraliz[e]” and then “biotreat[]” the Depot’s chemical weapons. 

(Aplt. Br., attach. 10.) That same year, the DOD contracted with “Bechtel Pueblo Team” 

to design, build, and operate a neutralization plant at the Depot. (Aplt. App. at 28 ¶ 9; 85 

¶ 9.) The Bechtel Pueblo Team broke ground on the plant in September 2004. The 

following month, however, the DOD suspended design work on the plant and, in January 

or February 2005, the DOD suspended construction. Construction resumed in March 

2005 on a scaled down version of the plant. 

 Initially, Congress directed that the Secretary of Defense destroy the United 

States’ chemical weapons by September 30, 1994, or instead by the date called for in “a 

treaty banning the possession of chemical agents and munitions,” if the United States 

ratified such a treaty. Pub. L. 99-145, 99 Stat. 583, § 1412(b)(1), (2) (Nov. 8, 1985). 

Congress has since extended that destruction deadline several times. And, in April 1997, 

the United States ratified the Chemical Weapons Convention treaty, which calls for the 

elimination of these weapons by 2012. Congress has currently extended the time the 

Secretary has to destroy these chemical weapons to the treaty’s 2012 deadline, or “not 
9 

later than December 31, 2017.”5 50 U.S.C. § 1521(b)(3) (2011). In the meantime, the 

Secretary must make annual and semi-annual reports to Congress regarding, among other 

things, the construction and operation of facilities to destroy chemical weapons, the 

anticipated schedule for the completion of the weapons destruction, and an assessment of 

the safety and integrity of the stockpile of chemical weapons awaiting destruction. See 

id. § 1521(i), (j). 

D. Colorado’s attempts to regulate the chemical weapons stored at the Depot 

 In 1980, while the EPA was still administering RCRA in Colorado, the Army 

notified the EPA that it was storing hazardous waste at the Depot in the form of leaking 

weapons and contaminated protection equipment. The EPA issued the Depot an interim 

permit to store this waste. In 1992, after the EPA turned the regulation of hazardous 

waste in Colorado over to the State, see 49 Fed. Reg. 41,036 (Oct. 19, 1984), Colorado 

issued the Army a ten-year permit to store this hazardous waste in four specified igloos.6 

In 2002, Colorado renewed that permit through September 2012. The parties thus refer to 

these four igloos as the “Permitted Igloos” (Aplt. App. at 26 ¶ 3; 85 ¶ 3), and do not 

dispute that the leaking chemical weapons and contaminated protective equipment 

contained in these Permitted Igloos qualify as hazardous waste restricted from land 

 

5

 According to the United States, Congress has amended 50 U.S.C. § 1521 on “at least 

fourteen occasions” and has changed the deadline for completion of the destruction of 

these weapons at least six times. (Aple. Br. at 4, 6-7.) 

6 Like federal law, see 42 U.S.C. § 6925, Colorado requires “[a]ny site or facility for the 

treatment, storage, or disposal of hazardous waste” to have a permit, Colo. Rev. Stat. 

§ 25-15-303(1). 
10 

disposal. 

 In 1985, as previously mentioned, Congress directed the Army to destroy all 

chemical weapons being stored at the Depot (and elsewhere). Twenty years later, 

however, after continued delay in the construction of the Depot’s neutralization plant, the 

CDPHE, on June 14, 2005, informed the Depot for the first time that Colorado deemed 

the Depot’s non-leaking and still usable chemical munitions to be hazardous waste 

restricted from ground disposal and, therefore, directed the Depot, within thirty days, to 

apply for a Part A permit to store such hazardous waste. 

Under Colorado law, 

[t]o obtain [such] a permit an applicant submits a Part A application, 

providing a general description of the applicant’s facility and hazardous 

waste management activities. More detailed information is required in a 

Part B application. Upon receipt of the Part A application, [Colorado] may 

allow the storage of hazardous waste on an interim basis. A final permit[, 

however,] will issue only upon [Colorado’s] approval of an applicant’s Part 

B submission. 

(Id. at 143 (district court’s order).) 

 In response to Colorado’s order that the Depot apply for a permit pertaining to the 

usable chemical weapons stored at the Depot, the Depot’s commander protested to the 

CDPHE that the non-leaking chemical weapons did not qualify as hazardous waste and, 

therefore, were not subject to regulation by Colorado. Nevertheless, on July 27, 2005, 

the Depot belatedly applied for a Part A hazardous waste permit to store these usable 

chemical munitions. In applying for that permit, however, the Depot declared that it was 

submitting its permit application only “as a matter of comity, and pending further action,” 

after noting that the Depot’s “longstanding and continued cooperation with CDPHE is 
11 

essential to meet treaty obligations and remain on the path to progress.” (Aple. Supp. 

App. at 40.) 

Six months later, CDPHE issued a compliance order effective February 13, 2006 

(the “2006 compliance order”). This order determined that the Depot had violated 

Colorado’s hazardous waste regulations by 1) not timely submitting a Part A permit 

application as directed and, thus, storing hazardous waste without a permit, and 

2) delaying the construction of the Depot’s neutralization plant. Nevertheless, CDPHE’s 

2006 compliance order gave the Depot “interim status” to store hazardous waste in what 

the parties refer to as the ninety-four “Interim Status Igloos.” (Aplt. App. at 31 ¶ 22.) 

The DOD did not administratively appeal the 2006 compliance order. 

That compliance order further required the Depot, among other things, to submit a 

treatment plan to Colorado that would describe the means by which the chemical 

munitions would be treated and neutralized, along with a schedule for when that would 

occur. The order further required that the submitted treatment schedule insure that the 

neutralization plant would be constructed by September 30, 2007, and that all of the 

chemical weapons stored at the Depot would be destroyed “by April 29, 2012, or as 

specified in the Plan submitted [by the Depot to Colorado before] September 30, 2006, or 

as subsequently modified in annual reports” that the Depot was to file with the CDPHE. 

(Aple. Supp. App. at 19.) 

In an effort to comply with this order, the Depot submitted a treatment plan to 

Colorado in September 2006 calling for the complete destruction of the chemical 

weapons by 2020. In 2007, the Depot amended its plan, indicating instead that the 
12 

weapons would not be completely destroyed until 2021. These dates are well beyond the 

congressionally mandated December 2017 destruction deadline. See 50 U.S.C. 

§ 1521(b)(3) (2011). 

 Dissatisfied with the Depot’s projected destruction dates, CDPHE, on June 16, 

2008, issued another compliance order (the “2008 compliance order”) requiring the 

Depot to submit a new plan that 1) provided for the complete neutralization of all of the 

Depot’s chemical weapons by December 31, 2017, and 2) further provided for interim 

deadlines enforceable against the Depot. This time the Depot filed an administrative 

appeal challenging this 2008 compliance order. CDPHE then withdrew its 2008 

compliance order and initiated this litigation. 

E. Procedural background 

 In this litigation, Colorado sued a number of defendants (collectively the “United 

States”), seeking to compel compliance with the State’s hazardous waste regulation. 

Specifically, Colorado alleged that the United States was not complying with 6 Colo. 

Code. Regs. § 268.50, which prohibits the storage of any hazardous waste that has been 

restricted from land disposal. Colorado asserted two claims for relief based upon this 

theory, the first claim alleging that the Depot’s storage of usable chemical weapons in the 

ninety-four “Interim Status Igloos” violated § 268.50, and the second claim alleging that 

the Depot’s storage of leaking chemical weapons and contaminated protective equipment 

in the four “Permitted Igloos” also violated § 268.50. As remedies, Colorado sought 1) a 

mandatory injunction requiring Defendants to comply with Colorado’s Hazardous Waste 

Management Act and 6 Colo. Code Regs. § 268.50; 2) a mandatory injunction requiring 
13 

Defendants to submit a treatment plan to the State that would provide for destruction of 

the chemical munitions by December 31, 2017, as well as interim deadlines leading up to 

the complete neutralization of all chemical weapons located at the Depot; and 3) such 

other relief as the Court determines is appropriate.7

 

Colorado moved for partial summary judgment, seeking to establish Colorado’s 

authority to regulate the chemical weapons stored at the Depot. To that end, Colorado, in 

 

7

 Colorado specifically requested that the district court 

 1. Issue a mandatory injunction requiring compliance with the 

[CHWMA] and Regulations § 268.50; 

 2. Issue a mandatory injunction requiring submission to the 

[CDPHE] for its review and approval a Chemical Weapons Waste 

Treatment Plan for the treatment of all Hazardous Waste Chemical 

Munitions and Hazardous Waste Agent in both the Permitted Igloos and the 

Interim Status Igloos, and requiring such plan to include the following: 

 a. a complete project schedule that depicts the tasks 

necessary for the destruction of all Hazardous Waste Chemical 

Munitions and Hazardous Waste Agent at [the Depot] with a 

completion date of December 31, 2017; and 

 b. allowance for designation of certain tasks throughout the 

schedule as “milestones” by the [CDPHE]. “Milestones” will be 

deadlines enforceable by the [CDPHE] for those tasks; and 

 c. the technical rationale for the proposed schedule; and 

 d. quarterly updates describing the progress made toward 

achieving the tasks and milestones, and any modifications or 

revisions to the project schedule or technical rationale contained in 

the Chemical Weapons Waste Treatment Plan. 

 3. Provide such other relief as the Court determines is appropriate. 

(Aplt. App. at 20-21.) 
14 

its motion for partial summary judgment, asked the district court to hold, among other 

things, that federal law does not preempt the State’s enforcement of its hazardous waste 

regulations against the Depot. The district court rejected that argument, concluding 

instead that federal law did preempt Colorado’s attempt to enforce against Defendants its 

regulation prohibiting storage of hazardous waste. At the parties’ request, the district 

court then entered judgment for the United States and dismissed Colorado’s claims. This 

appeal followed. 

II. STANDARD OF REVIEW 

 This court reviews the district court’s summary judgment decision de novo, 

viewing the evidence in the light most favorable to the non-moving party. See 

Oldenkamp v. United Am. Ins. Co., 619 F.3d 1243, 1246 (10th Cir. 2010). Summary 

judgment is appropriate “if the movant shows that there is no genuine dispute as to any 

material fact and the movant is entitled to judgment as a matter of law.” Fed. R .Civ. P. 

56(a). We also review de novo the legal question of whether federal law preempts state 

law. See Russo v. Ballard Med. Prods., 550 F.3d 1004, 1010 (10th Cir. 2008). 

III. PRELIMINARY MATTERS 

Before considering the preemption question, we address several preliminary 

issues. As an initial matter, we clarify the question presented by this appeal. In its 

motion for partial summary judgment, Colorado asked the district court to conclude that 

Colorado had authority to regulate the chemical weapons stored at the Depot and, in 

support of that conclusion, to make four determinations. First, Colorado asked the court 

to decide that the CDPHE has authority generally to regulate hazardous waste in 
15 

Colorado, and that Congress has waived the United States’ sovereign immunity, 

subjecting federal facilities to the State’s hazardous waste regulation. The district court 

did not specifically address these contentions because none of the parties disputed them. 

Next, Colorado asked the district court to determine both that “[t]he materials 

stored in the Interim Storage Igloos and the Permitted Igloos at the [Depot] are hazardous 

wastes,” and that Colorado’s regulations “prohibiting long-term storage of hazardous 

wastes apply to the materials stored” in those igloos. (Aplt. App. at 48.) The district 

court declined to resolve either of these two questions. Nor will we address them. 

Instead, for our purposes here only, we assume both that the materials stored in all of the 

igloos are hazardous waste restricted from land disposal and that Colorado’s hazardous 

waste regulations, promulgated after the United States began storing chemical weapons at 

the Depot, apply to the stored materials. 

The fourth issue Colorado asked the district court to determine was whether 

federal law preempted the enforcement of the CHWMA and its regulations against the 

Depot under the circumstances of this case. The district court addressed that question, 

deciding that under these circumstances federal law preempted application of Colorado’s 

hazardous waste regulations to the chemical weapons stored at the Depot. That is the 

sole issue we address here. 

One other preliminary matter we must address is Colorado’s argument that the 

district court erred “by ruling on the Constitutional issue of preemption” before deciding 

the other, non-Constitutional issues presented by this case, including whether the 

chemical weapons stored at the Depot are hazardous waste subject to Colorado’s 
16 

hazardous waste regulations. (Aplt. Br. at 6.) It was Colorado, however, that expressly 

asked the district court to resolve the preemption issue. In any event, the district court 

did not err in addressing the dispositive preemption issue first. While it is true that 

federal preemption of state law is grounded in the Supremacy Clause of the United States 

Constitution, the Supreme Court has treated preemption “as ‘statutory’ for purposes of 

[the Court’s] practice of deciding statutory claims first to avoid unnecessary 

constitutional adjudications.” Douglas v. Seacoast Prods., Inc., 431 U.S. 265, 272 

(1977); see also C.E.R. 1988, Inc. v. Aetna Cas. & Sur. Co., 386 F.3d 263, 272 n.13 (3d 

Cir. 2004); Knudsen Corp. v. Nev. State Dairy Comm’n, 676 F.2d 374, 377 (9th Cir. 

1982) (noting that the question of preemption “is largely one of determining the 

compatibility of a state and a federal statutory scheme. No constitutional issues of 

substance are presented.”). But cf. Columbia Venture, LLC v. Dewberry & Davis, LLC, 

604 F.3d 824, 828 (4th Cir. 2010) (noting that a court should decide a case on an 

independent state-law basis if that basis allows the court to avoid deciding a 

constitutional question such as preemption). 

IV. PREEMPTION

A. Preemption principles generally 

 We turn now to the preemption question. In light of the federal Constitution’s 

Supremacy Clause,8

 “it has long been recognized that federal law preempts contrary state 

enactments.” Chamber of Commerce of the U.S. v. Edmondson, 594 F.3d 742, 765 (10th 

 

8

 The Supremacy Clause provides that “the Laws of the United States . . . shall be the 

supreme Law of the Land[,] . . . any Thing in the Constitution or Laws of any State to the 

Contrary notwithstanding.” U.S. Const. art. VI, cl. 2. 
17 

Cir. 2010); see also Arizona v. United States, 132 S. Ct. 2492, 2500 (2012). Such 

preemption can occur in one of three ways: 1) when a federal statute expressly preempts 

state law (“express preemption”); 2) where Congress intends to occupy a field (“field 

preemption”); and 3) to the extent that a state law conflicts with a federal law (“conflict 

preemption”). See Arizona, 132 S. Ct. at 2500-01; In re Universal Serv. Fund Tel. 

Billing Practice Litig., 619 F.3d 1188, 1195 (10th Cir. 2010). 

Here, the United States invokes only conflict preemption. See Cook v. Rockwell 

Int’l Corp., 618 F.3d 1127, 1143 n.16 (10th Cir. 2010) (declining to address field 

preemption because defendants failed to develop that argument in their appellate briefs or 

at oral argument), cert. denied, 79 U.S.L.W. 3662 (U.S. June 25, 2012) (Nos. 10-1377, 

10A845). The United States bears “the burden of showing that federal and state law 

conflict.” Id. at 1143. 

“Whatever its form, preemption analysis ‘starts with the assumption that the 

historic police powers of the States are not to be superseded by . . . [a] Federal Act unless 

that is the clear and manifest purpose of Congress. Accordingly, the purpose of Congress 

is the ultimate touchstone of pre-emption analysis.’” Emerson v. Kan. City S. Ry. Co., 

503 F.3d 1126, 1129 (10th Cir. 2007) (quoting Cipollone v. Liggett Grp., Inc., 505 U.S. 

504, 516 (1992)); see also Arizona, 132 S. Ct. at 2501. 

B. Applying Colorado’s regulation prohibiting storage of any hazardous waste 

restricted from land disposal, 6 Colo. Code Regs. § 268.50, to the Depot’s chemical 

weapons conflicts with Congress’s mandate in 50 U.S.C. §§ 1521 and 1512a 

“Conflict preemption occurs where it is impossible for a [regulated] party to 

comply with both state and federal requirements, or where state law stands as an obstacle 
18 

to the accomplishment and execution of the full purposes and objectives of Congress.” In 

re Universal Serv. Fund Tel. Billing Practice Litig., 619 F.3d at 1196 (internal quotation 

marks omitted); see also Arizona, 132 S. Ct. at 2501. 

Colorado sought from the district court partial summary judgment declaring that 

the State’s authority to enforce its hazardous waste regulation prohibiting the storage of 

any hazardous waste restricted from land disposal, 6 Colo. Code Regs. § 268.50§ 268.50, 

against the United States with regard to its storage of chemical weapons at the Depot. 

But the United States cannot comply with that State regulation, prohibiting the storage of 

any such hazardous waste, and also comply with Congress’s mandate that it must biotreat 

and neutralize the Depot’s chemical weapons at a plant built at the Depot solely for that 

purpose. It appears that the Depot has not yet completed constructing the plant. And 

Congress gave the Depot until December 2017 to destroy the chemical weapons in the 

plant.9

 

Colorado acknowledges that, in practical terms, the United States cannot 

immediately eliminate the chemical weapons currently stored at the Depot. The State 

 9 Colorado argues, for the first time in its reply brief on appeal, that federal law 

cannot preempt 6 Colo. Code Regs. § 268.50 because Congress, in enacting 50 U.S.C. 

§ 1521, did not expressly require that the United States store chemical weapons at the 

Depot. Though we need not address such a belatedly raised argument, see United States 

v. Bass, 661 F.3d 1299, 1301 n.1 (10th Cir. 2011), Colorado’s argument fails in any 

event. For preemption purposes, Congress’s intent need not be explicit; it can “be . . . 

implicitly contained in [the] structure and purpose” of the relevant statute. Cipollone, 

505 U.S. at 516 (internal quotation marks omitted). Here, because Congress prohibited 

the DOD from moving the Depot’s chemical weapons out of Colorado, and because 

Congress has set the 2017 deadline for the completion of their destruction, Congress has 

thus implicitly mandated that the DOD continue to store these weapons at the Depot for 

the time being. 
19 

nonetheless seeks to exercise its authority to prohibit the storage of any such hazardous 

waste by requiring the United States to follow a schedule that will ensure the destruction 

of the chemical weapons by a date certain. And, in an effort to avoid conflict 

preemption, Colorado selected as its date certain the same date as that currently provided 

by Congress, December 31, 2017.10 In addition to seeking to enforce the same deadline 

chosen by Congress, however, Colorado further seeks to provide interim project 

milestones that the State can enforce against the United States to insure its compliance 

with the 2017 deadline. 

To avoid conflict preemption, “‘it is not enough to say that the ultimate goal of 

both federal and state law is the same. A state law also is pre-empted if it interferes with 

the methods by which the federal statute was designed to reach this goal.’” Edmondson, 

594 F.3d at 769 (quoting Int’l Paper Co. v. Ouellette, 479 U.S. 481, 494 (1987) 

(alterations, citation omitted)); see also Arizona, 132 S. Ct. at 2505. And that is true here, 

as well. 

 Our conclusion, that Colorado cannot enforce its prohibition against the storage of 

any hazardous waste restricted from land disposal against the United States’ storage of 

chemical weapons at the Depot is founded on the detail Congress has provided regarding 

 

10 Colorado further asserts that, in the exercise of its authority to prohibit the storage of 

any hazardous waste restricted from land disposal, the State could require the United 

States to destroy the Depot’s chemical weapons earlier than Congress’s 2017 deadline, 

and such a requirement would not be inconsistent with the congressional mandate that the 

Army destroy these weapons “no later than” December 2017. Further, it appears likely 

that, if Colorado has authority to regulate the Depot’s chemical weapons, it will exercise 

that regulatory authority to continue to enforce the 2017 deadline even if Congress acts to 

extend the deadline for the destruction of these weapons. 
20 

how and when the DOD must destroy these weapons. While Congress directed the 

Secretary of Defense to destroy these weapons, Congress also acted to insure that the 

manner of their destruction “provide[s] for . . . maximum protection for the environment, 

the general public, and the personnel who are involved in the destruction,” and that the 

destruction occur in “adequate and safe facilities designed solely for the destruction.” 50 

U.S.C. § 1521(d)(1)(A), (B) (2011). To that end, Congress required testing of 

incineration as a method of destruction, and later directed the Secretary to explore 

alternative destruction methods, eventually settling on neutralization of the Depot’s 

weapons. Thus, Congress has required a measured pace in undertaking the destruction of 

these chemical weapons and, on at least six occasions, has extended the destruction 

deadline to accommodate that pace. This unmistakably indicates that Congress intended 

to reserve for itself the power and flexibility to establish and extend the destruction 

deadline, as well as to alter the process and timing by which these chemical weapons are 

destroyed. Moreover, Congress’s comprehensive treatment of the destruction of these 

weapons indicates that the timing of the weapons’ destruction is but one of several 

congressional goals addressed in Title 50. Permitting Colorado to be a second enforcer 

of the 2017 destruction deadline, and to add other enforceable interim deadlines of its 

own, interferes with the measured, flexible and frequently revised approach Congress has 

taken to destroy these weapons. 

 Our conclusion, that Colorado cannot enforce its prohibition against the storage of 

any hazardous waste restricted from land disposal against the United States’ storage of 

chemical weapons at the Depot, is bolstered by the Supreme Court’s recent decision in 
21 

Arizona v. United States, 132 S. Ct. 2505., (noting that, although Arizona’s law at issue 

in that case “attempts to achieve one of the same goals as federal law . . . , it involves a 

conflict in the method of enforcement. The Court has recognized that a conflict in 

technique can be fully as disruptive to the system Congress enacted as conflict in overt 

policy”) (quotation marks, alterations omitted). 

Understandably, Colorado has grown impatient with the delay in destroying the 

chemical weapons stored at the Depot. But compelling the United States, in its handling 

of these munitions, to comply with Colorado’s regulation prohibiting the storage of any 

hazardous waste restricted from land disposal will impede or interfere with the 

accomplishment of the objectives and purposes of 50 U.S.C. §§ 1512a and 1521. 

Therefore, 50 U.S.C. §§ 1512a and 1521 preempt Colorado’s enforcement of its 

regulation, 6 Colo. Code Regs. 268.50, against the United States under the circumstances 

presented here. See Arizona, 132 S. Ct. at 2505, 2507 (holding state law that interfered 

with, or presented an obstacle to, the accomplishment of Congress’s objectives was 

preempted under a theory of conflict preemption). 

Our earlier case of United States v. Colorado, 990 F.2d 1565 (10th Cir. 1993), on 

which the State relies, does not require a different conclusion. In that case, we held that 

Colorado could enforce its hazardous waste regulations, authorized by RCRA, “at a 

hazardous waste treatment, storage and disposal facility owned and operated by the 

federal government which the EPA ha[d] placed on the national [Superfund] priority list, 

and where a CERCLA [Comprehensive Environmental Response, Compensation, and 

Liability Act of 1980] response action [wa]s underway.” Colorado at 1568-69, 1584. 
22 

But Colorado was able to do so there because of two savings clauses that Congress 

included in CERCLA: 

CERCLA’s “savings provision” provides that “[n]othing in [CERCLA] 

shall affect or modify in any way the obligations or liabilities of any person 

under other Federal or State law, including common law, with respect to 

releases of hazardous substances or other pollutants or contaminants,’” 42 

U.S.C. § 9652(d) (West 1983). Similarly, CERCLA’s provision entitled 

“relationship to other laws” provides that “[n]othing in [CERCLA] shall be 

construed or interpreted as preempting any State from imposing any 

additional liability or requirements with respect to the release of hazardous 

substances within such State.” 42 U.S.C. § 9614(a) (West 1983). 

Id. at 1575-76 (footnote omitted; brackets in original). 

RCRA, too, similarly provides that “[n]othing in this chapter [referring to RCRA, 

42 U.S.C. §§ 6901-6992k] shall be construed to prohibit any State or political subdivision 

thereof from imposing any requirements, including those for site selection, which are 

more stringent that those imposed by [federal] regulations.” 42 U.S.C. § 6929. But it is 

not RCRA that preempts Colorado’s enforcement of its storage prohibition on the United 

States’ storage of chemical weapons at the Depot. Instead, it is 50 U.S.C. §§ 1512a and 

1521 that preempt Colorado’s enforcement of its storage prohibition under the 

circumstances presented here. And those federal statutes do not include any savings 

language. 

On appeal, Colorado seeks to avoid preemption by asserting it only wants to 

exercise its regulatory authority under its regulation prohibiting the storage of any 

hazardous waste restricted from land disposal in order to enforce Congress’s own 2017 

deadline for the destruction of these chemical weapons. But Colorado can only enforce 

that, or any other, deadline against the Depot if Colorado has authority to regulate the 
23 

Depot’s stored chemical weapons in the first place. That is why Colorado sought partial 

summary judgment specifically to that effect. But we conclude, for the reasons stated 

above, that 50 U.S.C. §§ 1521 and 1512(a) preempt Colorado’s authority to regulate the 

Depot’s chemical weapons under the circumstances presented here. So it does not matter 

that Colorado only seeks to exercise its regulatory authority in a limited manner. Cf. 

Farina v. Nokia Inc., 625 F.3d 97, 133 (3d Cir. 2010), cert. denied, 132 S. Ct. 365 (2011) 

(“For the purposes of preemption analysis, it is the cause of action, and not the specific 

relief requested, that matters.”). 

IV. CONCLUSION 

 For the foregoing reasons, we conclude that 50 U.S.C. §§ 1512a and 1521 preempt 

Colorado’s application of its prohibition against the storage of any hazardous waste 

restricted from land disposal against the United States’ storage of chemical weapons at 

the Depot. Therefore, we AFFIRM the district court’s decision to dismiss Colorado’s 

claims as preempted by federal law.