FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,                
                   Plaintiff-Appellee,
                  v.
JAY MANNING, in his official
capacity as Director of the
Washington Department of
Ecology; WASHINGTON
DEPARTMENT OF ECOLOGY; STATE OF
WASHINGTON,
             Defendants-Appellants,
                                               No. 06-35613
                 and
                                                D.C. No.
YES ON I-297: PROTECT                        CV-04-05128-AAM
WASHINGTON; BOB APPLE;
WASHINGTON PUBLIC INTEREST
RESEARCH GROUP; ADAM KLINE;
TOBY NIXON; HEART OF AMERICA
NORTHWEST,
             Defendant-Intervenors,
                  v.
FLUOR HANFORD INC.; TRI-CITY
INDUSTRIAL DEVELOPMENT COUNCIL,
    Plaintiff-Intervenors-Appellees.
                                         




                              5881
5882               UNITED STATES v. MANNING



UNITED STATES OF AMERICA,                
                   Plaintiff-Appellee,
                  v.
JAY MANNING, in his official
capacity as Director of the
Washington Department of
Ecology; WASHINGTON
DEPARTMENT OF ECOLOGY; STATE OF
WASHINGTON,
                         Defendants,
                 and                           No. 06-35664
YES ON I-297: PROTECT                           D.C. No.
WASHINGTON; BOB APPLE;                       CV-04-05128-AAM
WASHINGTON PUBLIC INTEREST
RESEARCH GROUP; ADAM KLINE;
TOBY NIXON; HEART OF AMERICA
NORTHWEST,
             Defendant-Intervenors-
                          Appellants,
                  v.
FLUOR HANFORD INC.; TRI-CITY
INDUSTRIAL DEVELOPMENT COUNCIL,
    Plaintiff-Intervenors-Appellees.
                                         
                   UNITED STATES v. MANNING             5883



UNITED STATES OF AMERICA,                
                   Plaintiff-Appellee,
                  v.
JAY MANNING, in his official
capacity as Director of the
Washington Department of
Ecology; WASHINGTON
DEPARTMENT OF ECOLOGY; STATE OF
WASHINGTON,
              Defendants-Appellees,
                 and
                                               No. 06-35765
YES ON I-297: PROTECT
WASHINGTON; BOB APPLE;                          D.C. No.
                                             CV-04-05128-AAM
WASHINGTON PUBLIC INTEREST
RESEARCH GROUP; ADAM KLINE;                      OPINION
TOBY NIXON; HEART OF AMERICA
NORTHWEST,
             Defendant-Intervenors,
                  v.
FLUOR HANFORD INC.,
                 Plaintiff-intervenor,
                 and
TRI-CITY INDUSTRIAL DEVELOPMENT
COUNCIL,
     Plaintiff-Intervenor-Appellant.
                                         
       Appeals from the United States District Court
          for the Eastern District of Washington
       Alan A. McDonald, District Judge, Presiding

                 Argued and Submitted
          December 3, 2007—Seattle, Washington
5884                UNITED STATES v. MANNING
                       Filed May 21, 2008

  Before: M. Margaret McKeown and Richard R. Clifton,
 Circuit Judges, and William W Schwarzer,* District Judge.

                  Opinion by Judge McKeown




  *The Honorable William W Schwarzer, Senior United States District
Judge for the Northern District of California, sitting by designation.
5886             UNITED STATES v. MANNING


                        COUNSEL

Andrew A. Fitz, Assistant Attorney General (argued); Laura
J. Watson, Assistant Attorney General; and James R.
Schwartz, Assistant Attorney General; Olympia, Washington,
for the defendants-appellants, cross-appellees.

Michael Jay Robinson-Dorn (argued), Katy Anne King, Ian
Jeremy Mensher, and Joseph Shaughnessy, Seattle, Washing-
ton, for the intervenor-appellants.

John A. Bryson, Assistant United States Attorney (argued);
Matthew J. McKeown, Acting Assistant Attorney General;
Cynthia J. Morris, Assistant United States Attorney; Kenneth
                      UNITED STATES v. MANNING                       5887
C. Amaditz, Assistant United States Attorney; and David
Kaplan, Assistant United States Attorney; Washington, DC,
for the plaintiff-appellee.

Colin C. Deihl (argued) and Kristen S. Carney, Faegre &
Benson LLP, Denver, Colorado, for the intervenor-appellee
Fluor Hanford, Inc.

Matthew J. Segal (argued), Stephen A. Smith, and Michael K.
Ryan, Kirkpatrick & Lockhart Preston Gates Ellis LLP, Seat-
tle, Washington, for the intervenor-appellee, cross-appellant
Tri-City Industrial Development Council.


                              OPINION

McKEOWN, Circuit Judge:

   The Hanford Nuclear Reservation (“Hanford”) in Washing-
ton is one of the largest sites in the country for the treatment,
storage and disposal of radioactive and non-radioactive haz-
ardous waste, currently storing over 53 million gallons of
mixed radioactive and nonradioactive hazardous waste. Dur-
ing World War II, the United States government constructed
Hanford to manufacture plutonium for military purposes. In
re Hanford Nuclear Reservation Litig., ___ F.3d ___, 

, *4 (9th Cir. Apr. 4, 2008) (as amended).1 Over
the decades, the United States Department of Energy
(“DOE”) has disposed of approximately 450 billion gallons of
contaminated water and liquid mixed waste on the site. At
least one million gallons of high-level mixed radioactive and
non-radioactive hazardous waste have leaked into the envi-
ronment and approximately 170 miles of groundwater beneath
Hanford are contaminated. In addition, tens of millions of gal-
  1
    For almost twenty years there has been litigation over whether radioio-
dine from Hanford caused various cancers and life-threatening diseases in
residents of the surrounding area.
5888                 UNITED STATES v. MANNING
lons of waste are stored at Hanford in tanks that were con-
structed in the 1940s and meant to last only twenty years. As
of 2004, there was a backlog of over 22,000 cubic meters of
low-level mixed waste and transuranic mixed waste awaiting
treatment and disposal.

   In 1989, Washington’s Department of Ecology
(“Ecology”), the DOE, and the United States Environmental
Protection Agency (“EPA”) entered into the Hanford Federal
Facility Agreement and Consent Order, also known as the Tri-
Party Agreement, to bring Hanford into compliance with fed-
eral and state environmental laws. However, according to
Ecology, since signing the agreement, the DOE and its con-
tractors have been cited numerous times for violations of fed-
eral and state hazardous and mixed waste laws and
requirements.

   The present appeal arises out of an effort by Washington
voters “to prevent the addition of new radioactive and hazard-
ous waste to the Hanford nuclear reservation until the cleanup
of existing contamination is complete.” United States v. Hoff-
man, 

, 1001 (Wash. 2005). Although the desire
to take action against further environmental contamination
and to protect the health and welfare of the community is
understandable, we conclude that the statute enacted through
the passage of Initiative 297 (“I-297”), the Cleanup Priority
Act (“CPA”), is preempted by federal law. This result is dic-
tated by a plain reading of the Washington statute, as inter-
preted by the Washington Supreme Court, as well as long-
standing principles of federal preemption.

I.    BACKGROUND

     A.   GLOSSARY

  The field of environmental law has spawned multiple acro-
nyms. Many of these acronyms are well recognized, like EPA,
                 UNITED STATES v. MANNING             5889
while others, like HWMA, are not. For ease of reference, we
offer the following glossary of terms:

AEA        Atomic Energy Act of 42 U.S.C. §§ 2011-2259
           1954
CERCLA     Comprehensive           42 U.S.C. §§ 9601-9675
           Environmental
           Response,
           Compensation, and
           Liability Act of 1980
CPA        Cleanup Priority Act    RCW Chapter 70.105E
DOE        United States
           Department of Energy
EPA        United States
           Environmental
           Protection
Ecology    WashingtonAgency
                       State
           Department of Ecology
FFCA       Federal Facility        Pub. L. No. 102-386,
           Compliance Act of       106 Stat. 1505 (codified
           1992                    in scattered sections of
                                   42 U.S.C.)
HWMA       Hazardous Waste         RCW Chapter 70.105
           Management Act
MTCA       Model Toxics Control RCW Chapter 70.105D
           Act
RCRA       Resource Conservation 42 U.S.C. §§ 6901-
           and Recovery Act of 6992k
           1976
5890                 UNITED STATES v. MANNING
  B.    STATUTORY FRAMEWORK             FOR    HAZARDOUS WASTE
        MANAGEMENT

   Hazardous waste is regulated at both the federal and state
levels. The Resource Conservation and Recovery Act
(“RCRA”), 42 U.S.C. §§ 6901-6992k, enacted in 1976 in
response to the environmental and public health risks associ-
ated with the mismanagement of hazardous waste, created a
permit scheme for the treatment, disposal, or storage of haz-
ardous waste. See 

United States v. Kentucky,

, 822 (6th Cir. 2001). Under the RCRA, states
may apply to the EPA for authorization to administer a haz-
ardous waste program in lieu of the federal program. 42
U.S.C. § 6926(b). Washington is authorized to administer its
own program, and does so through the Hazardous Waste
Management Act (“HWMA”), RCW 70.105.

   Despite federal cleanup efforts, hazardous waste contami-
nation continued to be a problem. Ecology claims that federal
facilities, including Hanford, were among the worst offenders.
In 1992, Congress enacted the Federal Facilities Compliance
Act (“FFCA”) to make it “as clear as humanly possible” that
Congress was waiving federal sovereign immunity and mak-
ing federal facilities subject to state laws. 138 Cong. Rec.
H9135-02 (daily ed. Sept. 23, 1992) (statement of Rep. Din-
gell); see 42 U.S.C. § 6961. This act also added a provision
to the RCRA that requires the DOE to submit its treatment
plans for mixed waste to the states for approval, modification,
or disapproval. 42 U.S.C. § 6939c.

  Disposal of nuclear and radioactive materials falls into a
special category and is separately regulated by the federal
government. Thus, “solid waste” regulated by the RCRA does
not include “source, special nuclear, or byproduct material as
defined by the Atomic Energy Act of 1954.”2 42 U.S.C.
  2
   “Source material” includes uranium, thorium, and other materials that
the Nuclear Regulatory Commission deems necessary for the production
                      UNITED STATES v. MANNING                        5891
§ 6903(27). “The [Atomic Energy Act, (“AEA”), 42 U.S.C.
§§ 2011 2259] enacted in 1954, established a comprehensive
regulatory scheme for military and domestic nuclear energy.”
Natural Res. Def. Council v. Abraham, 

, 704 (9th
Cir. 2004). Amendments to the AEA in 1959 gave states some
regulatory authority, but the Atomic Energy Commission,
now the Nuclear Regulatory Commission, “retain[ed] exclu-
sive regulatory authority over ‘the disposal of such . . . bypro-
duct, source, or special nuclear material as the Commission
determines . . . should, because of the hazards or potential
hazards thereof, not be disposed of without a license from the
Commission.’ ”3 Silkwood v. Kerr-McGee Corp., 

, 250 (1984) (quoting 42 U.S.C. § 2021(c)(4)).

   Radioactive waste that is subject to regulation under the
AEA frequently may be mixed with non-radioactive waste
that is regulated by the RCRA. No separate federal statute
regulates this “mixed waste.”4 See 

.
However, the DOE and the EPA have issued rules stating that
mixed waste will be subject to dual regulation: the AEA will

of special nuclear material. 42 U.S.C. § 2014(z). “Special nuclear materi-
als” are those materials, such as plutonium and enriched uranium, that are
“enriched in the isotope 233 or in the isotope 235.” 

“By-
product material” includes “(1) any radioactive material (except special
nuclear material) yielded in or made radioactive by exposure to the radia-
tion incident to the process of producing or utilizing special nuclear mate-
rial, and (2) the tailings or wastes produced by the extraction or
concentration of uranium or thorium from any ore processed primarily for
its source material content.” 

(2).
   3
     Source material, special nuclear material, and byproduct material are
often referred to as “AEA materials.”
   4
     The State suggests that the RCRA and the FFCA give states the author-
ity to regulate the radioactive component of mixed waste. Neither federal
statute explicitly allows states to engage in broad regulation of the radio-
active component of mixed waste. The FFCA gives states a limited role
in mixed waste management by directing the DOE to submit plans regard-
ing mixed waste to states for approval, modification, or disapproval. 42
U.S.C. § 6939c; see also H.R. Conf. Rep. No. 102-866, at 22 (1992). Con-
gress stopped short, though, of giving states broader regulatory authority.
5892               UNITED STATES v. MANNING
govern the radioactive component and the RCRA or compara-
ble state legislation will govern the non-radioactive compo-
nent. See, e.g., 51 Fed. Reg. 24,504 (July 7, 1986); 52 Fed.
Reg. 15,937 (May 1, 1987); 53 Fed. Reg. 37,045 (Sept. 23,
1988). This dual regulatory structure is the source of the con-
flict engendered by the CPA.

  C.   THE CLEANUP PRIORITY ACT

   The ballot description of I-297 declared that “[t]his mea-
sure would add new provisions concerning ‘mixed’ radioac-
tive and nonradioactive hazardous waste, requiring cleanup of
contamination before additional waste is added, prioritizing
cleanup, [and] providing for public participation and enforce-
ment through citizen lawsuits.” Thus, the CPA “became part
of a complex state and federal system for regulating materials
that are variously described as hazardous, dangerous, radioac-
tive, or having some combination of these attributes.” Hoff-

. Counsel explained at oral argument
that the CPA, passed by Washington voters in November
2004, was meant to eliminate Ecology’s discretion in issuing
permits under the RCRA and the HWMA and in taking action
regarding investigation and cleanup.

   Toward those ends, § 4 of I-297 provides that a final facil-
ity permit cannot issue until all units of a facility are in com-
pliance with federal and state cleanup laws. Significantly, a
facility cannot import mixed waste until it obtains a final
facility permit. Section 5 requires that Ecology take remedial
and corrective action against releases of radionuclides into the
environment. Section 6 contains mandates to Ecology regard-
ing the investigation and cleanup of hazardous substances that
have been disposed of in unlined trenches, and the closure of
mixed waste tank systems. Section 7 requires Ecology to
obtain from mixed waste facility owners the projected costs
of remedial and corrective actions. Section 8 grants exemp-
tions from the CPA’s requirements for certain naval waste, in
accordance with the State’s obligations under the Northwest
                     UNITED STATES v. MANNING                       5893
Interstate Compact. Section 9 requires facilities where there
has been a release of mixed waste to provide for and fund a
broadly representative advisory board, and directs Ecology to
make available public participation grants that will be funded
by a mixed waste surcharge assessed against permit applicants
and permit holders. Finally, under § 10, the CPA is enforce-
able through citizen suits.

   The United States sought and obtained a temporary
restraining order in federal district court against the enforce-
ment of the CPA the day before its effective date, Decem-
ber 2, 2004.5 Various sponsors of I-297 intervened as
defendants (“Sponsors”). The United States argued that the
CPA was invalid in its entirety because it violated the
Supremacy Clause and the Commerce Clause of the United
States Constitution, and the sovereign immunity of the United
States. Fluor Hanford (“Fluor”), a private contractor operating
at Hanford, intervened as a plaintiff. The Tri-City Industrial
Development Council (“TRIDEC”), a not-for-profit corpora-
tion that represents local businesses and public entities in the
area around Hanford, also intervened as a plaintiff and
asserted that the CPA violated the Contract Clause.

D.    QUESTIONS CERTIFIED          TO    THE    WASHINGTON STATE
      SUPREME COURT

   The United States and Fluor filed for summary judgment
and TRIDEC filed for partial summary judgment. In opposing
the United States’ motion, the State argued that many of the
claims could be narrowed or eliminated through statutory
interpretation. See Hoff

. The parties
agreed that if the CPA covered only material that could be
regulated under state law or the RCRA, then the statute was
not preempted by federal law. The district court granted the
State’s motion to certify five questions to the Washington
  5
    Ultimately, the parties agreed to extend the temporary order until the
district court ruled on a motion for summary judgment.
5894              UNITED STATES v. MANNING
Supreme Court, including the following question and its sub-
parts that are directly relevant to this appeal:

    (1) What materials are encompassed within the
    definition of “mixed waste” set forth in Section 3(9)
    of the CPA [RCW 70.105E.030(9)]?

    (a) Specifically, does the definition of “mixed
    waste” encompass materials that consist solely of
    radioactive source, special nuclear, or byproduct
    materials and, if so, under what circumstances does
    the CPA apply to such materials?

    (b) Specifically, does the definition of “mixed
    waste” encompass materials that are mixtures of
    radioactive source, special nuclear, or byproduct
    materials and other hazardous substances that do
    no[t] designate as “dangerous waste” under state
    laws? If so, under what circumstances does the CPA
    apply to such materials?

    (c) Specifically, does the definition of “mixed
    waste” encompass materials that are not “solid
    wastes” under the Resource Conservation and
    Recovery Act (RCRA) and, if so, under what cir-
    cumstances does the CPA apply to such materials?

    (d) In light of the Court’s answers to subparts (a)
    through (c), above, does the definition of “mixed
    waste” expand the scope of materials regulated as
    mixed waste under the Washington Hazardous
    Waste Management Act (HWMA) and RCRA?

  The Washington Supreme Court accepted certification and,
among others, answered Question 1. The court began its anal-
ysis by tracing the definition of “mixed waste,” as used in the
                       UNITED STATES v. MANNING                        5895
CPA, through its cross-references to other federal and state
statutes. See 

Under the CPA, “mixed waste”
is defined as:

       [A]ny hazardous substance or dangerous or
       extremely hazardous waste that contains both a non-
       radioactive hazardous component and a radioactive
       component, including any such substances that have
       been released to the environment, or pose a threat of
       future release, in a manner that may expose persons
       or the environment to either the nonradioactive or
       radioactive hazardous substances.

RCW 70.105E.030(9). The court observed that the CPA’s
definition of “mixed waste” incorporated the term “hazardous
substance,” which is, in turn, defined as having “the same
meaning as the term is defined in [the Model Toxics Control
Act (“MTCA”), RCW 70.105D.020].”6 

. The MTCA is “ ‘designed to deal both with the
remediation of former environmental hazards and to prevent
  6
   Under the MTCA, “hazardous substance” is defined as:
      (a) Any dangerous or extremely hazardous waste as defined in
      RCW 70.105.010(5) and (6), or any dangerous or extremely dan-
      gerous waste designated by rule pursuant to chapter 70.105
      RCW;
      (b) Any hazardous substance as defined in RCW 70.105.010(14)
      or any hazardous substance as defined by rule pursuant to chapter
      70.105 RCW;
      (c) Any substance that, on March 1, 1989, is a hazardous sub-
      stance under section 101(14) of the federal cleanup law, 42
      U.S.C. Sec. 9601(14):
      (d) Petroleum or petroleum products; and
      (e) Any substance or category of substances, including solid
      waste decomposition products, determined by the director by rule
      to present a threat to human health or the environment if released
      into the environment.
RCW 70.105D.020(10).
5896                   UNITED STATES v. MANNING
environmental hazards in the future,’ ” and makes a property
owner “ ‘strictly liable for the remediation of environmental
hazards caused by hazardous substances it released [or were
released] on its property.’ ” Goodstein v. Cont’l Cas. Co., 

, 1046 n.2 (9th Cir. 2007) (quoting Olds-Olympic,
Inc. v. Commercial Union Ins. Co., 

, 927 (Wash.
1996)). The MTCA’s definition of “hazardous substance,” in
turn, cross-references the definition of “hazardous substance”
in the HWMA, RCW 70.105D.020(7)(b).7 

.

   As to Question 1(a), the parties agreed that the CPA does
not address materials that are solely “of radioactive source,
special nuclear, or byproduct materials.” 

to
Question 1(b), the court concluded that the CPA’s definition
of “mixed waste” includes material that does not designate as
“dangerous waste” under the MTCA and the HWMA. 

Waste must meet certain threshold quantity require-
ments of certain materials before it will designate as “danger-
ous waste,” 

WAC 173-303-090(8)(a)-(c), but a
“hazardous substance,” as defined by the HWMA, has no
threshold requirement. 

; RCW
70.105.010(14). Because the HWMA’s definition of “hazard-
ous substance” is incorporated into the CPA’s definition of
“mixed waste,” “mixed waste” can include materials that will
not designate as “dangerous waste” because those materials
do not meet the threshold quantity requirement.

  With respect to Question 1(c), the court concluded that the
CPA’s definition of “mixed waste” included materials that
were not “solid waste” under the RCRA. Hoffman, 

   Under the HWMA, “hazardous substances” are defined as:
      [A]ny liquid, solid, gas, or sludge, including any material, sub-
      stance, product, commodity, or waste, regardless of quantity, that
      exhibits any of the characteristics or criteria of hazardous waste
      as described in rules adopted under this chapter.
RCW 70.105.010(14).
                   UNITED STATES v. MANNING                  5897
at 1006. In light of its analysis of questions 1(a)-(c), the
Washington Supreme Court held that “the CPA does expand
the scope of materials currently subject to regulation as mixed
waste beyond the HWMA and the RCRA.” 

(responding to Question 1(d)).

  E.    THE DISTRICT COURT’S DECISION

   The district court addressed the motion for summary judg-
ment in a careful and extensive (sixty-page) order. Relying on
the Washington Supreme Court’s conclusions that the CPA’s
definition of “mixed waste” includes materials that do not
designate as “dangerous waste” and materials that are not
“solid waste” under the RCRA, the district court held that the
CPA was preempted by federal law because it improperly
intruded on the field governed by the AEA by regulating
byproduct, source, or special nuclear material. The court fur-
ther held that specific provisions of the statute violated federal
sovereign immunity and the Commerce Clause. In addition,
the court granted TRIDEC’s motion for partial summary judg-
ment and held that the CPA also violated the Contract Clause.
The court denied TRIDEC’s motion for attorney’s fees under
42 U.S.C. § 1988, which is the subject of its cross-appeal. We
review de novo the district court’s rulings on summary judg-
ment. Buono v. Norton, 

, 545 (9th Cir. 2004).

II.    ANALYSIS

   Generally speaking, “mixed waste” is waste that has both
a nonradioactive hazardous component and a radioactive
component. Unquestionably, the State has the authority to
regulate nonradioactive hazardous materials, and does so pri-
marily through the RCRA and the HWMA. The parties also
agree that the regulation of pure radionuclides is governed by
the AEA. The question we address here is whether the regula-
tion of the radioactive component of mixed waste is pre-
empted by the AEA.
5898               UNITED STATES v. MANNING
  A.   FIELD PREEMPTION

   [1] As the Supreme Court observed, state law can be pre-
empted in either of two general ways: if “Congress evidences
an intent to occupy a given field,” or, if the field has not been
occupied entirely, “to the extent it actually conflicts with fed-
eral law . . . or where the state law stands as an obstacle to
the accomplishment of the full purposes and objectives of
Congress.” 

. In a landmark case
involving nuclear regulation, the Court declared that “the fed-
eral government has occupied the entire field of nuclear safety
concerns, except the limited powers expressly ceded to the
states.” Pac. Gas & Elec. Co. v. State Energy Res. Conserva-
tion & Dev. Comm’n, 

, 212 (1983). To determine
whether the CPA is preempted by the AEA, “the test . . . is
whether ‘the matter on which the state asserts the right to act
is in any way regulated by the federal government.’ ” 

(quoting Rice v. Santa Fe Elevator Corp., 

,
236 (1947)). The AEA preempts the CPA if (1) the purpose
of the CPA is to regulate against radiation hazards, or (2) if
the CPA directly affects decisions concerning radiological
safety. See English v. Gen. Elec. Co., 

, 84 (1990).
We hold that the CPA is preempted on both grounds.

   The district court concluded that the CPA intruded into the
AEA field because its purpose was to regulate the safety of
radionuclides. Relying on the Washington Supreme Court’s
analysis, it held that “[t]he CPA exceeds RCRA authority and,
as such, intrudes upon a field (regulation of AEA radionu-
clides for radiological safety purposes), which is preempted
by the AEA.” See 42 U.S.C. §§ 6903(5), (27). The court noted
that “[t]he CPA makes the presence of radioactive materials,
whether or not a component of ‘mixed waste,’ as defined by
the CPA, the trigger for all of its requirements.” As a further
basis for preemption, the district court’s order listed eight
ways in which the CPA would have a “direct and substantial
effect on the decisions made by those who build or operate
nuclear facilities concerning radiological safety levels[.]”
                      UNITED STATES v. MANNING                       5899
      1.   The CPA’s Purpose is to Regulate Radioactive
           Materials

   The CPA is preempted because it regulates within the field
that is occupied by the AEA.8 It is abundantly clear from the
text of the CPA that it is intended to regulate both nonradioac-
tive hazardous substances and radioactive hazardous sub-
stances in order to protect health and environmental safety.

   [2] The “Policy” section of the CPA, which corresponds to
§ 2 of I-297, is telling as to the State’s intent to regulate radio-
active safety. Section 2(1) describes Hanford as a dump for
“radioactive and/or hazardous or toxic wastes[.]” RCW
70.105E.020(1) (emphasis added). Subsection 4 warns that
Washington’s economy could be harmed “from any accident
releasing radiation[.]” RCW 70.105E.020(4) (emphasis
added). Subsection 6 expresses the state policy of protecting
residents from cancer-causing substances, “including radionu-
clides[.]” RCW 70.105E.020(6).

   [3] The substantive provisions of the statute also squarely
regulate both the nonradioactive and radioactive components
of hazardous waste. For example, the first sentence of § 4(2)
states:

      Any facility owner or operator of a site storing, man-
      aging, processing, transferring, treating, or disposing
      of mixed wastes shall apply for and obtain a final
      facility permit under [the HWMA], this chapter, and
  8
   Because the CPA is invalid under the Supremacy Clause, we do not
need to reach the additional constitutional challenges. Although we do not
reach the issue of sovereign immunity or the challenges under the Com-
merce Clause and the Contract Clause, we decline to vacate those portions
of the district court’s order as the State requests. Rather, we simply
express no view on issues unnecessary to this opinion. See Niagara
Mohawk Power Corp. v. Tonawanda Band of Seneca Indians, 

, 754 (2d Cir. 1996) (declining a request to vacate an alternative basis
for the judgment below).
5900                  UNITED STATES v. MANNING
     [RCRA], before transporting to, storing or disposing
     at, the facility any additional mixed wastes not gen-
     erated at the facility.

RCW 70.105E.040(2). This section imposes a condition on
the ability of facility owners to accept mixed waste that is
generated off-site. Simply because the permit is issued under
the RCRA does not require the term “mixed waste” to be
interpreted in a way that excludes the radioactive component,
an interpretation that would be at odds with the interpretation
of the Washington Supreme Court. Similarly, § 6(1) directs
Ecology to order “site” owners and operators where “mixed
wastes” are believed to be disposed to cease disposal and ini-
tiate investigations. RCW 70.105E.060(1)(a).

   [4] Some provisions in the CPA regulate “pure” AEA
radionuclides. For example, under § 4(6)(b), Ecology is
directed to not issue or modify a permit if there has been a
release of radionuclides at the site or facility. RCW
70.105E.040(6)(b). Section 5 requires Ecology to “consider
releases . . . of radioactive substances or radionuclides as haz-
ardous substances” and to “require corrective action for, or
remediation of, such releases[.]”9 RCW 70.105E.050(1).

   [5] The purpose of the CPA is evident in these provisions:
to regulate the treatment, storage, and disposal of radioactive
   9
     The State argues that § 5(1) only regulates radiological safety in the
context of environmental releases and, therefore, is outside the scope of
the AEA and consistent with permissible state regulation under CERCLA.
Through CERCLA, Congress allows states to apply their “laws concerning
removal and remedial action” to federally-owned facilities. 42 U.S.C.
§ 9620(a)(4). However, § 5(1) directs Ecology to “require corrective
action for, or remediation of” releases of radioactive substances. RCW
70.105E.050(1). “Corrective action” is not defined in the CPA, but is a
term that is used in connection with the RCRA. See 42 U.S.C. § 6924.
Because radioactive materials are excluded from the RCRA, requiring a
corrective action for the release of radionuclides exceeds the authority of
the RCRA.
                   UNITED STATES v. MANNING                 5901
materials, among other materials, in order to protect the health
and safety of Washington residents and the environment.
Such regulation, however laudable its purpose, invades the
province of the AEA.

   The Sixth Circuit’s decision in United States v. Kentucky is
particularly 

. There, the court
addressed whether the AEA preempted state permit condi-
tions on the disposal of radioactive waste in a landfill. The
conditions prohibited the DOE from placing solid waste with
more than a de minimis amount of radioactivity in a landfill
and further prohibited the DOE from disposing of solid waste
that contained radionuclides in a landfill without approval
from Kentucky’s Division of Waste Management. 

The court noted that these permit conditions “specifically
limit the amount of ‘radioactivity’ and ‘radionuclides.’ ” 

It explained that the state “seeks to impose these condi-
tions to protect human health and the environment. The per-
mit conditions therefore represent an opportunity by the
[state] to regulate materials covered by the AEA based on the
[state’s] safety and health concerns, and are thus preempted.”

Kentucky, the State here seeks to impose conditions
on the disposal of AEA materials out of concern for the health
and environmental risks that increased contamination will
cause. This type of regulation falls squarely within the field
preempted by the AEA.

   The State attempts to sidestep the preemption issue by
shifting the applicable definitions, contending that it is rea-
sonable to read “mixed waste” within the operative provisions
of the CPA as limited to the materials that may be regulated
under the RCRA and the HWMA. This construction is neither
reasonable nor legally permissible.

  The State’s argument fails at the outset because we are
bound by the Washington Supreme Court’s opinion that
5902               UNITED STATES v. MANNING
“mixed waste” includes more than the materials regulated
under the RCRA and the HWMA. See Reinkemeyer v. Safeco
Ins. Co. of Am., 

, 984 (9th Cir. 1999) (explaining
that “[w]e are bound by the answers of state supreme courts
to certified questions just as we are bound by state supreme
court interpretations in other contexts.”). The Supreme Court
has explained that “state courts are the ultimate expositor of
state law [and] we are bound by their constructions except in
extreme circumstances[.]” Mullaney v. Wilbur, 

,
691 (1975). In other words, the State cannot re-litigate its
argument that “mixed waste” should be read narrowly without
invoking one of the “few established grounds for disregarding
a state court interpretation of state law.” 

. The State does not point to any “obvious subter-
fuge to evade consideration of a federal issue” or a “violation
of federal law” that could undercut the Washington Supreme
Court’s analysis. See 

n.11;

.

   The State’s position is somewhat curious because it was at
the State’s urging that the district court certified to the state
supreme court questions that would determine whether
“mixed waste” included substances that were not regulated
under the RCRA or the HWMA. See Hoff

-02. The court answered in the affirmative. 

.
In arriving at this construction, the court rejected the argu-
ments that the State and the Sponsors advance now that “the
CPA’s reference to ‘hazardous substances’ is necessarily lim-
ited to only those materials that have been released or pose a
threat of release [making] the CPA . . . coextensive with the
HWMA and the RCRA.” 

(emphasis in original).
The court refused to “ignore the direct cross-references incor-
porating the expansive definition of ‘hazardous substances’ in
RCW 70.105.010(14).” 

that the
word ‘waste’ limits the application of otherwise clear and
unequivocal statutory definitions to circumstances of ‘release
or threatened release’ is wholly without merit.” 

pointedly noted that it was “left with a choice between two
                   UNITED STATES v. MANNING                  5903
alternatives”: “a plain language interpretation based on the
statutory definitions of ‘mixed waste’ and ‘hazardous sub-
stance,” as espoused by the United States, or Ecology’s posi-
tion which would “artificially eliminate much of the substance
of these definitions.” 

In the end, Ecology’s “artifi-
cial limitation would require [the court] to ignore long-held
rules of statutory interpretation.” 

now argues that, under Salerno, we cannot invali-
date a statute as unconstitutional if there is a reasonable, con-
stitutional construction. It is equally true, though, that we
cannot rewrite the statute to impose an artificial, unreasonable
definition, Virginia v. Am. Booksellers Ass’n, Inc., 

, 397 (1988); United States v. Buckland, 

,
564 (9th Cir. 2002) (en banc), nor can we hold that the CPA
is co-extensive with the RCRA and the HWMA when the
state supreme court has expressly ruled otherwise.

  [6] A key purpose of the CPA is to regulate the radioactive
component of mixed waste, as well as the nonradioactive
component, for health and safety reasons. Accordingly, the
CPA is preempted by the AEA. Except for “limited powers
ceded to the states,” and not disputed here, “the federal gov-
ernment has occupied the entire field of nuclear safety con-
cerns.” Pac. Gas & 

.

    2.   Direct and Substantial Effects

   [7] The CPA is also preempted because it directly and sub-
stantially impacts the DOE’s decisions on the nationwide
management of nuclear waste. See 

.
According to the declaration of Dr. Ines Triay, Chief Operat-
ing Officer for Environmental Management at the DOE, Han-
ford figures prominently in the DOE’s waste management
plan. Hanford is the only federal facility that can accept off-
site mixed low level waste for disposal. The use of commer-
cial facilities for disposal is limited because their long-term
availability is uncertain and because commercial licenses pre-
5904                 UNITED STATES v. MANNING
clude the facilities from accepting higher-activity mixed low-
level waste, classified waste, and other types of waste. The
DOE’s National Laboratories plan to dispose of their waste at
Hanford because that waste is too radioactive to be sent to a
commercial facility, or is classified. Hanford is the only via-
ble option for some sites with higher-activity mixed low-level
waste.

   In particular, the Navy disposes of radioactive waste
(which also contains hazardous substances, as defined by the
CPA) that is generated through the maintenance and repair of
nuclear powered ships at shipyards in Washington at Hanford.
If Hanford was unavailable, it is possible, but “uncertain,”
whether the Navy can dispose of the waste at another site.

   [8] The district court enumerated eight different direct and
substantial effects that flow from the CPA.10 It wrote that “the
defendants do not deny that these things happen, but assert
there is no guarantee they will depending on the State’s inter-
pretation and implementation of the CPA.” Yet again, the
State tries to hide behind an as-yet-to-be-determined interpre-
tation and implementation of the statute when the state
supreme court has already laid out, in binding terms, the
scope of the CPA. Finally, the State’s contention that the CPA
does not have a direct and substantial effect on the DOE’s
decision-making because the DOE is not currently shipping
waste to Hanford misses the point. The facilities at Hanford
are part of the DOE’s overall nuclear waste management plan.
Legislation geared to effectively close Hanford for an
extended period of time directly affects the DOE’s ability to
make decisions regarding if and when it will ship additional
  10
    For example, the district court explained that the CPA would have the
direct and substantial effect of prohibiting the Navy from sending certain
classified nuclear waste to Hanford, trump DOE decision-making with
respect to the cleanup and disposal of AEA radionuclides, including any
expansion of any land disposal unit for radionuclides, and prevent the
DOE from using methods it deems appropriate for closing tanks that con-
tain AEA radionuclides.
                   UNITED STATES v. MANNING                 5905
waste to Hanford. Because of these direct and substantial
effects, the CPA is preempted.

  B.   SAVINGS CLAUSE

   [9] The CPA contains a savings clause that authorizes Ecol-
ogy to “regulate mixed wastes to the fullest extent it is not
preempted by federal law[.]” RCW 70.105E.040(1). Regula-
tion of the radioactive component of mixed waste is pre-
empted by federal law. The CPA regulates mixed waste as a
whole and certain provisions contain specific mandates con-
cerning the radioactive component. The definitional cross-
references and intersection with multiple state and federal
statutes make the CPA a complex regulatory web. For exam-
ple, in the CPA, the focus is on “mixed waste,” without distin-
guishing the radioactive component from the “hazardous”
component, and yet the HWMA focuses on “hazardous
waste,” even where it is a component of “mixed waste.”

   [10] Although it might be possible to excise those provi-
sions that deal solely with radioactive materials, to construe
the remaining sections of the CPA as limited to the nonradio-
active component would require us to examine and rewrite
most of the statute in a vacuum as to how the various provi-
sions were intended to intersect and in a way that would be
at odds with the purpose of the statute. See Alaska Airlines v.
Brock, 

, 684 (1987) (“ ‘Unless it is evident that
the Legislature would not have enacted those provisions
which are within its power, independently of that which is
not, the invalid part may be dropped if what is left is fully
operative as a law.’ ”) (quoting Buckley v. Valeo, 

,
108 (1976) (per curiam)). We will not undertake this task of
unscrambling the egg. See Planned Parenthood of Idaho, Inc.
v. Wasden, 

, 937 (9th Cir. 2004) (noting the
court’s “previously expressed concern that federal courts
ought not be redrafting state statutes at the level of individual
words”). And, as a practical matter, excising the most signifi-
5906              UNITED STATES v. MANNING
cant conflicts in the statute would result in a very difficult
statute than the one envisioned by I-297.

   [11] The CPA is preempted by the AEA because its pur-
pose is to regulate AEA materials for safety purposes and
because the CPA has a direct and substantial effect on the
DOE’s ability to make decisions regarding the disposal of
radioactive hazardous waste. The district court’s grant of
summary judgment to the United States, Fluor, and TRIDEC
is affirmed.

III.   TRIDEC’S CROSS-APPEAL FOR ATTORNEY’S FEES

   [12] TRIDEC’s cross-appeal challenges the district court’s
denial of its motion for attorney’s fees under 42 U.S.C.
§ 1988. The district court resolved this case under the
Supremacy Clause, holding that “the CPA is field preempted
and facially invalid as a whole.” We have affirmed that result.
Attorney’s fees are not available in an action under the
Supremacy Clause. Golden State Transit Corp. v. City of Los
Angeles, 

, 107 (1989). The district court also
identified other deficiencies and addressed the Commerce
Clause and Contract Clause arguments, but only as alternative
holdings and to avoid piecemeal appeal. In addition, the court
noted that the judgment had not changed the legal relationship
among the parties, as the State “had taken no action in the
first instance to enforce the CPA against the members of TRI-
DEC.” See Texas State Teachers Ass’n v. Garland Indep. Sch.
Dist., 

(1989) (holding that to be considered
a prevailing party under § 1988, there must be “a resolution
of the dispute which changes the legal relationship” between
the plaintiff and the defendant). The district court’s denial of
TRIDEC’s motion for attorney’s fees is affirmed.

  AFFIRMED.