PUBLISH

UNITED STATES COURT OF APPEALS

TENTH CIRCUIT

COLORADO DEPA RTMENT 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 Court2 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, Rich ard E. Lotz, Assistan t Attorney General, with him on the briefs), Denver, Co lorado 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, Colo rado (“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 th at state. Invoking that regulatory authority, Plaintiff-Appellant Colorado Department of Public Health and E nvironment, Hazardous Materials and Waste Management Division (“Colorado” or “CDPHE”), has declared the chemical weapons stored at the Depot awaiting de struction to be hazard ous 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, U nder Secretary of Defense Frank Kendall is substituted for former Under Secretary John J. Young, Jr., Assembled Chemical Weapons Alternatives Program Ma nager Conrad F. Whyne is substituted for former manager Kevin Flamm, and Lieute nant Colonel Timothy M. Greenhaw is substituted for Lieutenant Colonel Robert Wittig.3 action, Colorado seeks to enforce against the Depot Co lorado’s regulation prohibiting storage of any hazardous waste. The specific question presented by this a ppeal 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 regul ation prohibiting storage of any hazardous

waste. This case thus lies at the intersecti on of congressional mandates that, under these circumstances, support op posing positions. Based on the fa ct that Congress 1) delegated

to Colorado the au thority to regulate hazardous waste, so long as the State’s regulations are at least as stringent as federal hazardo us waste regulations, a nd 2) required federal agencies to follow such state hazardous waste regulation, Co lorado argues that the United States, in operating the Depot, must comply with the State’s prohibition against storing

hazardous waste. Based instead on the fa ct that Congress mandated that the Army destroy the chemical weapons at the Depot and gave the Army un til 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 oppo sing congressional mandates. Ultimately we are persuaded by the detailed ma nner with which Congress has

addressed and mandated the destruction of th e chemical weapons stored at the Depot to conclude that that federal law preempts Colo rado’s attempt to regulate that destruction process by enforcing its prohibitio n 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 cl aims against the United States.4 I. BACKGROUND

A. Colorado’s federally-derived author ity to regulate hazardous waste In 1976, Congress enact ed the Resource Conser vation and Recovery Act (“RCRA”), see 42 U.S.C. §§ 6901-6992k, in part to establish “a comprehensive regulatory scheme for the transportation, treatm ent, and disposal of hazardous wastes.” United States v. Magnesiu m Corp., 616 F.3d 1129, 1131-32 (10th Cir. 2010) (citing RCRA’s Subtitle C, codified at 42 U.S.C. §§ 6921-6939f). Congre ss charged the federal Environmental Protection Agency (“EPA”) with administering RCRA. See United States v. Power Eng’g Co., 303 F.3d 1232, 1236 (1 0th Cir. 2002). Nevertheless, a state can apply to the EPA “for authorization to admi nister and enforce its own hazardous waste program [so long as] its program is equivale nt 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. Re v. Stat. §§ 25-15-301 to -327, and in 1984, the EPA authorized Colorado “to operate its hazardou s 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 Ci r. 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” regul ations 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 re gulations 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, 1504-0 5 (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 exam ple, 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 fede ral 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. §§ 69 01-6992k] shall be construed to prohibit any State or politi cal subdivision thereof from imposing any requirements, including those for site selec tion, 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 enou gh 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 dis posal,” so storage for that purpose is not at issue.6 imposed by [federal] regulations.” 3 42 U.S.C. § 6929 (e mphasis added).

Pursuant to the Federal F acilities Compliance Act, the fe deral government and its agencies must comply with an EPA authorized state pr ogram 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. § 69 61(a)). The United States ha s thus waived its sovereign immunity from state-imposed permit requirement s, 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 inst allations 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-e ight “igloos,” which are “earthen-covered concrete structures.” (Aplt. App. at 82 ; Aple. Supp. App. at 36 ¶ 3; 55 ¶ 3.) Four of these ninety-eight igl oos 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 regula tion 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 incorpor ated 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 chem ical weapons. 50 U.S.C. § 1521(a). In 1994, Congress forbad e the Secretary from transporti ng “any chemical munition that constitutes part of the chemical weapons stockp ile 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 th e Depot’s chemical w eapons 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 ar e involved in the destruction of the lethal chemical agents and munitions . . . , including but not limited to the use of te chnologies and procedures that will minimize risk to the pu blic at each site; and (B) adequate and safe facil ities designed solely for the destruction of lethal chem ical 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 orig inally intended to incinera te 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, Congre ss 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. Weap ons Working Grp., 111 F.3d at 1487-88.8 By 1993, the Army had determ ined that it could incinerate the chemical weapons. See Chem. Weapons Working Gr p., 111 F.3d at 1487-88. Severa l storage sites other than the Depot then began the process of building incineration plants and incinerating their stored chemical weapons. In 1996, however, Congress di rected the DOD to explore alternative methods of destroying these chemical weapons. After c onsidering available alternatives, the DOD, in 2002, decided to “neutraliz [e]” and then “biotr eat[]” 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 plan t at the Depot. (Aplt. App. at 28 ¶ 9; 85 ¶ 9.) The Bechtel Pueblo T eam broke ground on the plan t in September 2004. The following month, however, the DOD suspended de sign work on the plant and, in January or February 2005, the DOD suspended cons truction. Construction resumed in March 2005 on a scaled down version of the plant. Initially, Congress directed that the S ecretary of Defense destroy the United States’ chemical weapons by Se ptember 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, § 14 12(b)(1), (2) (Nov. 8, 1985). Congress has since extended that destruction d eadline several times. And, in April 1997,

the United States ratified th e Chemical Weapons Convention treaty, which calls for the elimination of these weapon s by 2012. Congress has cu rrently extended the time the Secretary has to destroy these chemical weap ons to the treaty’s 2012 deadline, or “not9 later than December 31, 2017.” 5 50 U.S.C. § 1521(b)(3) (2 011). In the meantime, the Secretary must make annual and semi-annua l reports to Congress regarding, among other things, the construction and operation of fa cilities to destroy chem ical weapons, the anticipated schedule for the co mpletion 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 th e 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 wa ste at the Depot in the form of leaking weapons and contaminated protection equipmen t. The EPA issued the Depot an interim permit to store this waste. In 1992, afte r 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 th is 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 qualif y as hazardous waste restricted from land

5 According to the United Stat es, Congress has amended 50 U.S.C. § 1521 on “at least fourteen occasions” and has changed the dead line 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, Colo rado 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, C ongress directed the Army to destroy all chemical weapons being stored at the De pot (and elsewhere). Twenty years later, however, after continued delay in the construc tion of the Depot’s neutralization plant, the CDPHE, on June 14, 2005, in formed the Depot for the firs t time that Colorado deemed the Depot’s non-leaking and still usable ch emical munitions to be hazardous waste restricted from ground disposal a nd, therefore, directed the De pot, within th irty 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 descri ption of the applicant’ s facility and hazardous waste management activities. More de tailed information is required in a Part B application. Upon receipt of the Part A a pplication, [C olorado] may allow the storage of hazardous waste on an interim basis. A final permit[, however,] will issue only up on [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 Depo t, the Depot’s commander protested to the CDPHE that the non-leaking chemical weapons did not qualify as ha zardous waste and, therefore, were not subject to regulation by Colorado. Ne vertheless, on July 27, 2005, the Depot belatedly applied for a Part A h azardous waste permit to store these usable chemical munitions. In applyi ng for that permit, however, th e Depot declared that it was submitting its permit applicatio n only “as a matter of comity, and pending further action,” after noting that the Depot’s “longstanding and continued cooperation with CDPHE is11 essential to meet treaty obliga tions and remain on the path to progress.” (Aple. Supp. App. at 40.) Six months later, CDPHE issued a complia nce 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 subm itting a Part A permit application as directed and, thus, stor ing 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 appe al the 2006 compliance order. That compliance order furthe r 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 a nd neutralized, along with a sc hedule for when that would occur. The order further requi red that the submitted treatmen t schedule insure that the neutralization plant would be constructed by September 30, 2007, and that all of the chemical weapons stored at the Depot woul d be destroyed “by Ap ril 29, 2012, or as specified in the Plan submitte d [by the Depot to Colorado be fore] September 30, 2006, or as subsequently modified in annual reports” th at the Depot was to file with the CDPHE. (Aple. Supp. App. at 19.)

In an effort to co mply 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 amen ded its plan, indicating instead that the12 weapons would not be complete ly destroyed until 2021. Thes e 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 weap ons by December 31, 2017, and 2) further provided for interim

deadlines enforceable against the Depot. This time th e Depot filed an administrative appeal challenging this 2 008 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 Unite d States was not complying with 6 Colo. Code. Regs. § 268.50, which pr ohibits the storage of any ha zardous waste that has been restricted from land disposal. Colorado assert ed two claims for relief based upon this theory, the first claim alleging that the Depot’s storage of us able 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 we apons 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. Co de Regs. § 268.50; 2) a ma ndatory injunction requiring13 Defendants to submit a treatment plan to the State that would provide for destruction of the chemical munitions by Decemb er 31, 2017, as well as inte rim deadlines leading up to the complete neutralization of all chemical weapons located at th e Depot; and 3) such

other relief as the Court de termines is appropriate. 7 Colorado moved for partial summary judg ment, seeking to establish Colorado’s authority to regulate the chemical weapons stored at the Depot. To that end, Colorado, in

7 Colorado specifically request ed that the district court 1. Issue a mandatory injuncti on requiring compliance with the [CHWMA] and Regulations § 268.50; 2. Issue a mandatory injunction requiring submission to the [CDPHE] for its review and appr oval 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 su ch 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 Ag ent 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 descri bing 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 th e Court determines is appropriate. (Aplt. App. at 20-21.)14 its motion for partial summary judgment, aske d 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 Stat es and dismissed Colorado’s claims. This appeal followed.

II. STANDARD OF REVIEW

This court reviews the district cour t’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, 1 010 (10th Cir. 2008). III. PRELIMINARY MATTERS Before considering the preemption ques tion, 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 as ked the district court to conclude that Colorado had authority to regu late the chemical weapons st ored at the Depot and, in support of that conclusion, to make four de terminations. First, Colorado asked the court

to decide that the CDPHE has authority generally to regulate hazardous waste in15 Colorado, and that Congre ss has waived the United States’ sovereign immunity, subjecting federal facilities to the State’s haza rdous waste regulation. The district court did not specifically address thes e 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 “p rohibiting long-term st orage of hazardous wastes apply to the materials stored” in those igloos. (Aplt. App. at 48.) The district

court declined to resolve e ither 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 la nd 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 dist rict 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 c ourt addressed that question, deciding that under these circumstances fede ral 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 a ddress is Colorado’s argument that the district court erred “by ruling on the Constituti onal issue of preemption” before deciding the other, non-Constitutional issues presen ted by this case, in cluding whether the chemical weapons stored at the Depot ar e hazardous waste subject to Colorado’s16 hazardous waste regulations. (Aplt. Br. at 6. ) It was Colorado, however, that expressly

asked the district court to reso lve the preemption issue. In any event, the district court did not err in addressing the dispositive preemp tion 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 ‘statuto ry’ for purposes of [the Court’s] practice of deciding stat utory 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 preemp tion “is largely one of determining the compatibility of a state and a federal statut ory scheme. No constitutional issues of substance are presented.”). But cf. Columbia Venture, LLC v. Dewb erry & 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 basi s allows the court to avoid deciding a constitutional question such as preemption). IV. PREEMPTION A. Preemption principles generally We turn now to the preem ption question. In light of the federal Constitution’s Supremacy Clause, 8 “it has long been reco gnized 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 La ws 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 St ates, 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 st ate law conflicts with a federal law (“conflict preemption”). See Arizona, 132 S. Ct. at 250 0-01; In re Universa l Serv. Fund Tel. Billing Practice Litig., 619 F.3d 1188, 1195 (10th Cir. 2010). Here, the United States invokes only conf lict preemption. See Cook v. Rockwell Int’l Corp., 618 F.3d 1127, 1143 n.16 (10th Cir. 2010) (d eclining to address field preemption because defendants fail ed to develop that argument in their appellate briefs or at oral argument), cert. deni ed, 79 U.S.L.W. 3662 (U.S. J une 25, 2012) (Nos. 10-1377, 10A845). The United States bears “the burde n of showing that federal and state law

conflict.” Id. at 1143. “Whatever its form, preemption analysis ‘starts with the a ssumption 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 Co ngress. Accordingly, the purpose of Congress

is the ultimate touchstone of pre-emption analysis.’” Emers on 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 ma ndate 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 wher e state law stands as an obstacle18 to the accomplishment and execut ion of the full purposes and ob jectives of Congress.” In re Universal Serv. Fund Tel. Billing Practice Litig., 619 F.3d at 1196 (internal quotation marks omitted); see also Arizon a, 132 S. Ct. at 2501. Colorado sought from th e district court partial summa ry judgment declaring that the State’s authority to enfo rce its hazardous waste regula tion prohibiting the storage of any hazardous waste restricted from land dis posal, 6 Colo. Code Re gs. § 268.50§ 268.50, against the United States with regard to its storage of chem ical 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 w ith Congress’s mandate that it must biotreat and neutralize the Depot’s chemic al 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 acknowledge s that, in practical terms, the United States cannot immediately eliminate the chem ical weapons currently stored at the Depot. The State

9 Colorado argues, for the firs t 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 Un ited States store chem ical 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 Ci r. 2011), Colorado’s ar gument fails in any event. For preemption purposes , Congress’s intent need not be explicit; it can “be . . . implicitly contained in [the] st ructure and purpose” of the re levant 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 deadlin e 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 St ates 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, howeve r, 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 preem ption, “‘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 25 05. And that is true here,

as well. Our conclusion, that Colorado cannot enfo rce its prohibition against the storage of any hazardous waste restricted from land dis posal 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 author ity to prohibit the storage of any hazardous waste restricted from land di sposal, the State could require the United States to destroy the Depot’s chemical w eapons earlier than C ongress’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 chemic al weapons, it will exercise that regulatory authority to con tinue to enforce the 2017 dead line even if Co ngress acts to extend the deadline for the dest ruction of these weapons.20 how and when the DOD must destroy thes e weapons. While Co ngress directed the Secretary of Defense to destroy these weapon s, 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 th e 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, a nd later directed the Secretary to explore alternative destruction methods, eventually settling on neutralization of the Depot’s weapons. Thus, Congress has required a measur ed pace in undertaki ng the destruction of these chemical weapons and, on at least six occasions, ha s 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 a nd timing by which these chemical weapons are destroyed. Moreover, Congre ss’s comprehensive treatment of the destruction of these weapons indicates that the timing of the we apons’ destruction is but one of several congressional goals addressed in Title 50. Pe rmitting 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 enfo rce its prohibition against the storage of any hazardous waste restricted from land dis posal against the United States’ storage of chemical weapons at the Depot, is bolstered by the Supreme Court’s recent decision in21 Arizona v. United States, 132 S. Ct. 2505., (noting that, a lthough Arizona’s law at issue in that case “attempts to achi eve one of the same goals as federal law . . . , it involves a

conflict in the method of enforcement. Th e Court has recognized that a conflict in technique can be fully as disr uptive to the system Congress enacted as conflict in overt policy”) (quotation marks, alterations omitted). Understandably, Colorado has grown impatie nt with the delay in destroying the chemical weapons stored at the Depot. But compelling the United St ates, in its handling of these munitions, to comply with Colorado’s regulation prohibiting the storage of any hazardous waste restricted from land dispos al will impede or interfere with the accomplishment of the objectives and purpo ses 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, agains t 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 obst acle to, the accomplishment of Congress’s objectives was preempted under a theory of conflict preemption).

Our earlier case of United States v. Colo rado, 990 F.2d 1565 (10th Cir. 1993), on which the State relies, does not re quire a different conclusion. In that case, we held that

Colorado could enforce its hazardous wast e regulations, authorized by RCRA, “at a hazardous waste treatment, storage and disp osal facility owned and operated by the federal government which the EPA ha[d] placed on the national [Superf und] priority list, and where a CERCLA [Comprehensive Envi ronmental 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 beca use of two savings clauses that Congress

included in CERCLA: CERCLA’s “savings provision” provi des that “[n]othing in [CERCLA] shall affect or modify in any way th e obligations or lia bilities of any person under other Federal or State law, in cluding common law, with respect to releases of hazardous s ubstances or other polluta nts or contaminants,’” 42 U.S.C. § 9652(d) (West 1983). Sim ilarly, CERCLA’s provision entitled “relationship to other laws” provides that “[n]othing in [CERCLA] shall be construed or interpreted as pree mpting 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] sha ll be construed to prohibit a ny State or political subdivision thereof from imposing any requirements, includi ng 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 Colora do’s enforcement of its stor age prohibition on the United States’ storage of chemical weapons at the De pot. Instead, it is 50 U.S.C. §§ 1512a and 1521 that preempt Colorado ’s enforcement of its st orage prohibition under the circumstances presented here. And those fe deral statutes do not include any savings language. On appeal, Colorado seeks to avoid preemption by a sserting it only wants to exercise its regulatory auth ority under its regulation pr ohibiting 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 Colo rado can only enforce that, or any other, deadline against the Depot if Colorado has author ity to regulate the23 Depot’s stored chemical weapon s 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. §§ 15 21 and 1512(a) preempt Colorado’ s authority to regulate the Depot’s chemical weapon s under the circumstances presente d here. So it does not matter that Colorado only s eeks to exercise its regulatory au thority in a limited manner. Cf. Farina v. Nokia Inc., 625 F.3d 97, 133 (3d Cir. 2010), cert. de nied, 132 S. Ct. 365 (2011) (“For the purposes of preemptio n analysis, it is the cause of action, and not the specific relief requested, that matters.”). IV. CONCLUSION For the foregoing reasons, we conclude th at 50 U.S.C. §§ 1512 a and 1521 preempt Colorado’s application of its prohibition ag ainst the storage of any hazardous waste restricted from land disposal against the Unite d States’ storage of chemical weapons at the Depot. Therefore, we AFFIRM the dist rict court’s decision to dismiss Colorado’s claims as preempted by federal law.