Coeur Alaska, Inc. v. Southeast Alaska Conservation Council , 129 S. Ct. 2458 ( 2009 )


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  • (Slip Opinion)              OCTOBER TERM, 2008                                       1
    Syllabus
    NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
    being done in connection with this case, at the time the opinion is issued.
    The syllabus constitutes no part of the opinion of the Court but has been
    prepared by the Reporter of Decisions for the convenience of the reader.
    See United States v. Detroit Timber & Lumber Co., 
    200 U.S. 321
    , 337.
    SUPREME COURT OF THE UNITED STATES
    Syllabus
    COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL ET AL.
    CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
    THE NINTH CIRCUIT
    No. 07–984.      Argued January 12, 2009—Decided June 22, 2009*
    In reviving a closed Alaska gold mine using a “froth flotation” tech
    nique, petitioner Coeur Alaska, Inc., plans to dispose of the resulting
    waste material, a rock and water mixture called “slurry,” by pumping
    it into a nearby lake and then discharging purified lake water into a
    downstream creek. The Clean Water Act (CWA), inter alia, classifies
    crushed rock as a “pollutant,” §352(6); forbids its discharge “[e]xcept
    as in compliance” with the Act, §301(a); empowers the Army Corps of
    Engineers (Corps) to “issue permits . . . for the discharge of . . . fill
    material,” §404(a); and authorizes the Environmental Protection
    Agency (EPA) to “issue a permit for the discharge of any pollutant,”
    “[e]xcept as provided in [§404],” §402(a). The Corps and the EPA to
    gether define “fill material” as any “material [that] has the effect of
    . . . [c]hanging the bottom elevation” of water, including “slurry . . . or
    similar mining-related materials.” 40 CFR §232.2. Coeur Alaska ob
    tained a §404 permit for the slurry discharge from the Corps and a
    §402 permit for the lake water discharge from the EPA.
    Respondent environmental groups (collectively, SEACC) sued the
    Corps and several of its officials under the Administrative Procedure
    Act, arguing that the CWA §404 permit was not “in accordance with
    law,” 
    5 U.S. C
    . §706(2)(A), because (1) Coeur Alaska should have
    sought a CWA §402 permit from the EPA instead, just as it did for
    the lake water discharge; and (2) the slurry discharge would violate
    the “new source performance standard” the EPA had promulgated
    under CWA §306(b), forbidding froth-flotation gold mines to dis
    ——————
    * Together with No. 07–990, Alaska v. Southeast Alaska Conservation
    Council et al., also on certiorari to the same court.
    2           COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Syllabus
    charge “process wastewater,” which includes solid wastes, 40 CFR
    §440.104(b)(1). Coeur Alaska and petitioner Alaska intervened as de
    fendants. The District Court granted the defendants summary
    judgment, but the Ninth Circuit reversed, holding that the proposed
    slurry discharge would violate the EPA’s performance standard and
    §306(e).
    Held:
    1. The Corps, not the EPA, has authority to permit the slurry dis
    charge. Pp. 9–13.
    (a) By specifying that, “[e]xcept as provided in . . . [§404,]” the
    EPA “may . . . issue permit[s] for the discharge of any pollutant,”
    §402(a) forbids the EPA to issue permits for fill materials falling un
    der the Corps’ §404 authority. Even if there were ambiguity on this
    point, it would be resolved by the EPA’s own regulation providing
    that “[d]ischarges of . . . fill material . . . which are regulated under
    section 404” “do not require [EPA §402] permits.” 40 CFR §122.3.
    The agencies have interpreted this regulation to essentially restate
    §402’s text, ibid., and the EPA has confirmed that reading before this
    Court. Because it is not “plainly erroneous or inconsistent with the
    regulation,” the Court accepts the EPA’s interpretation as correct.
    Auer v. Robbins, 
    519 U.S. 452
    , 461. Thus, the question whether the
    EPA is the proper agency to regulate the slurry discharge depends on
    whether the Corps has authority to do so. If so, the EPA may not
    regulate. Pp. 9–11.
    (b) Because §404(a) empowers the Corps to “issue permits . . . for
    the discharge of . . . fill material,” and the agencies’ joint regulation
    defines “fill material” to include “slurry . . . or similar mining-related
    materials” having the “effect of . . . [c]hanging the bottom elevation”
    of water, 40 CFR §232.2, the slurry Coeur Alaska wishes to discharge
    into the lake falls well within the Corps’ §404 permitting authority,
    rather than the EPA’s §402 authority. The CWA gives no indication
    that Congress intended to burden industry with the confusing divi
    sion of permitting authority that SEACC’s contrary reading would
    create. Pp. 11–13.
    2. The Corps acted in accordance with law in issuing the slurry dis
    charge permit to Coeur Alaska. Pp. 13–28.
    (a) The CWA alone does not resolve these cases. Pp. 14–18.
    (i) SEACC contends that because the EPA’s performance stan
    dard forbids even minute solid waste discharges, 40 CFR
    §440.104(b)(1), it also forbids Coeur Alaska’s slurry discharge, 30% of
    which is solid waste, into the lake. Thus, says SEACC, the slurry
    discharge is “unlawful” under CWA §306(e), which prohibits “any
    owner . . . of any new source to operate such source in violation of any
    standard of performance applicable to such source.” Pp. 14–16.
    Cite as: 557 U. S. ____ (2009)                       3
    Syllabus
    (ii) Petitioners and the federal agencies counter that CWA
    §404 grants the Corps authority to determine whether to issue a
    permit allowing the slurry discharge without regard to the EPA’s
    new source performance standard or §306(e)’s prohibition. Pp. 16–18.
    (iii) The CWA is ambiguous on the question whether §306 ap
    plies to discharges of fill material regulated under §404. On the one
    hand, §306 provides that a discharge that violates an EPA new
    source performance standard is “unlawful”—without an exception for
    fill material. On the other hand, §404 grants the Corps blanket au
    thority to permit the discharge of fill material—without mentioning
    §306. This tension indicates that Congress has not “directly spoken”
    to the “precise question” at issue. Chevron U. S. A. Inc. v. Natural
    Resources Defense Council, Inc., 
    467 U.S. 837
    , 842. P. 18.
    (b) Although the agencies’ regulations construing the CWA are
    entitled to deference if they resolve the statutory ambiguity in a rea
    sonable manner, see Chevron, supra, at 842, the regulations bearing
    on §§306 and 404, like the CWA itself, do not do so. For example,
    each of the two principal regulations seems to stand on its own with
    out reference to the other. The EPA’s performance standard contains
    no exception for fill material, and it forbids any discharge of “process
    wastewater,” including solid wastes. 40 CFR §440.104(b)(1). The
    agencies’ joint regulation defining fill material includes “slurry or . . .
    similar mining-related materials,” §232.2, but contains no exception
    for slurry regulated by an EPA performance standard. Additional
    regulations noted by the parties offer no basis for reconciliation.
    Pp. 18–20.
    (c) In light of the ambiguities in the CWA and the pertinent regu
    lations, the Court turns to the agencies’ subsequent interpretation of
    those regulations. Auer, supra, at 461. The question at issue is ad
    dressed and resolved in a reasonable and coherent way by the two
    agencies’ practice and policy, as recited in the EPA’s internal “Regas
    Memorandum” (Memorandum), which explains that the performance
    standard applies only to the discharge of water from the lake into the
    downstream creek, and not to the initial discharge of slurry into the
    lake. Though the Memorandum is not subject to sufficiently formal
    procedures to merit full Chevron deference, the Court defers to it be
    cause it is not “plainly erroneous or inconsistent with the regula
    tion[s],” Auer, supra, at 461. Five factors inform that conclusion: The
    Memorandum (1) confines its own scope to closed bodies of water like
    the lake here, thereby preserving a role for the performance stan
    dards; (2) guards against the possibility of evasion of those standards;
    (3) employs the Corps’ expertise in evaluating the effects of fill mate
    rial on the aquatic environment; (4) does not allow toxic compounds
    to be discharged into navigable waters; and (5) reconciles §§306, 402,
    4           COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Syllabus
    and 404, and the regulations implementing them, better than any of
    the parties’ alternatives. The Court agrees with the parties that a
    two-permit regime is contrary to the statute and regulations. Pp. 20–
    23.
    (d) The Court rejects SEACC’s contention that the Regas Memo
    randum is not entitled to deference because it contradicts the agen
    cies’ published statements and prior practice. Though SEACC cites
    three such statements, its arguments are not convincing. Pp. 23–28.
    (i) Although a 1986 memorandum of agreement (MOA) be
    tween the EPA and the Corps seeking to reconcile their then-differing
    “fill material” definitions suggests, as SEACC asserts, that §402 will
    “normally” apply to discharges of “suspended”—i.e., solid—pollutants,
    that statement is not contrary to the Regas Memorandum, which ac
    knowledges that the EPA retains authority under §402 to regulate
    the discharge of suspended solids from the lake into downstream wa
    ters. The MOA does not address the question presented by these
    cases, and answered by the Regas Memorandum, and is, in fact, con
    sistent with the agencies’ determination that the Corps regulates all
    discharges of fill material and that §306 does not apply to these dis
    charges. Pp. 23–25.
    (ii) Despite SEACC’s assertion that the fill regulation’s pream
    ble demonstrates that the fill rule was not intended to displace the
    pre-existing froth-flotation gold mine performance standard, the pre
    amble is consistent with the Regas Memorandum when it explicitly
    notes that the EPA has “never sought to regulate fill material under
    effluent guidelines,” 67 Fed. Reg. 31135. If a discharge does not qual
    ify as fill, the EPA’s new source performance standard applies. If the
    discharge qualifies as fill, the performance standard does not apply;
    and there was no earlier agency practice or policy to the contrary.
    Pp. 25–26.
    (iii) Remarks made by the two agencies in promulgating the fill
    regulation, which pledge that the EPA’s “previou[s] . . . determina
    tion[s]” with regard to the application of performance standards “re
    main vali[d],” are not conclusive of the question at issue. The Regas
    Memorandum has followed this policy by applying the performance
    standard to the discharge of water from the lake into the creek. The
    remarks do not state that the EPA will apply such standards to dis
    charges of fill material. Pp. 26–27.
    (iv) While SEACC cites no instance in which the EPA has ap
    plied a performance standard to a discharge of fill material, Coeur
    Alaska cites two instances in which the Corps issued a §404 permit
    authorizing a mine to discharge solid waste as fill material. These
    permits illustrate that the agencies did not have a prior practice of
    applying EPA performance standards to discharges of mining wastes
    Cite as: 557 U. S. ____ (2009)                  5
    Syllabus
    that qualify as fill material. Pp. 27–28.
    
    486 F.3d 638
    , reversed and remanded.
    KENNEDY, J., delivered the opinion of the Court, in which ROBERTS,
    C. J., and THOMAS, BREYER, and ALITO, JJ., joined, and in which SCALIA,
    J., joined in part. BREYER, J., filed a concurring opinion. SCALIA, J.,
    filed an opinion concurring in part and concurring in the judgment.
    GINSBURG, J., filed a dissenting opinion, in which STEVENS and SOUTER,
    JJ., joined.
    Cite as: 557 U. S. ____ (2009)                              1
    Opinion of the Court
    NOTICE: This opinion is subject to formal revision before publication in the
    preliminary print of the United States Reports. Readers are requested to
    notify the Reporter of Decisions, Supreme Court of the United States, Wash
    ington, D. C. 20543, of any typographical or other formal errors, in order
    that corrections may be made before the preliminary print goes to press.
    SUPREME COURT OF THE UNITED STATES
    _________________
    Nos. 07–984 and 07–990
    _________________
    COEUR ALASKA, INC., PETITIONER
    07–984              v.
    SOUTHEAST ALASKA CONSERVATION COUNCIL
    ET AL.
    ALASKA, PETITIONER
    07–990               v.
    SOUTHEAST ALASKA CONSERVATION COUNCIL
    ET AL.
    ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
    APPEALS FOR THE NINTH CIRCUIT
    [June 22, 2009]
    JUSTICE KENNEDY delivered the opinion of the Court.
    These cases require us to address two questions under
    the Clean Water Act (CWA or Act). The first is whether
    the Act gives authority to the United States Army Corps of
    Engineers, or instead to the Environmental Protection
    Agency (EPA), to issue a permit for the discharge of min
    ing waste, called slurry. The Corps of Engineers has
    issued a permit to petitioner Coeur Alaska, Inc. (Coeur
    Alaska), for a discharge of slurry into a lake in Southeast
    Alaska. The second question is whether, when the Corps
    issued that permit, the agency acted in accordance with
    law. We conclude that the Corps was the appropriate
    agency to issue the permit and that the permit is lawful.
    With regard to the first question, §404(a) of the CWA
    2       COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    grants the Corps the power to “issue permits . . . for the
    discharge of . . . fill material.” 86 Stat. 884; 
    33 U.S. C
    .
    §1344(a). But the EPA also has authority to issue permits
    for the discharge of pollutants. Section 402 of the Act
    grants the EPA authority to “issue a permit for the dis
    charge of any pollutant” “[e]xcept as provided in” §404. 
    33 U.S. C
    . §1342(a). We conclude that because the slurry
    Coeur Alaska wishes to discharge is defined by regulation
    as “fill material,” 40 CFR §232.2 (2008), Coeur Alaska
    properly obtained its permit from the Corps of Engineers,
    under §404, rather than from the EPA, under §402.
    The second question is whether the Corps permit is
    lawful. Three environmental groups, respondents here,
    sued the Corps under the Administrative Procedure Act,
    arguing that the issuance of the permit by the Corps was
    “not in accordance with law.” 
    5 U.S. C
    . §706(2)(A). The
    environmental groups are Southeast Alaska Conservation
    Council, Sierra Club, and Lynn Canal Conservation (col
    lectively, SEACC). The State of Alaska and Coeur Alaska
    are petitioners here.
    SEACC argues that the permit from the Corps is unlaw
    ful because the discharge of slurry would violate an EPA
    regulation promulgated under §306(b) of the CWA, 
    33 U.S. C
    . §1316(b). The EPA regulation, which is called a
    “new source performance standard,” forbids mines like
    Coeur Alaska’s from discharging “process wastewater” into
    the navigable waters. 40 CFR §440.104(b)(1). Coeur
    Alaska, the State of Alaska, and the federal agencies
    maintain that the Corps permit is lawful nonetheless
    because the EPA’s performance standard does not apply to
    discharges of fill material.
    Reversing the judgment of the District Court, the Court
    of Appeals held that the EPA’s performance standard
    applies to this discharge so that the permit from the Corps
    is unlawful.
    Cite as: 557 U. S. ____ (2009)            3
    Opinion of the Court
    I
    A
    Petitioner Coeur Alaska plans to reopen the Kensington
    Gold Mine, located some 45 miles north of Juneau, Alaska.
    The mine has been closed since 1928, but Coeur Alaska
    seeks to make it profitable once more by using a technique
    known as “froth flotation.” Coeur Alaska will churn the
    mine’s crushed rock in tanks of frothing water. Chemicals
    in the water will cause gold-bearing minerals to float to
    the surface, where they will be skimmed off.
    At issue is Coeur Alaska’s plan to dispose of the mixture
    of crushed rock and water left behind in the tanks. This
    mixture is called slurry. Some 30 percent of the slurry’s
    volume is crushed rock, resembling wet sand, which is
    called tailings. The rest is water.
    The standard way to dispose of slurry is to pump it into
    a tailings pond. The slurry separates in the pond. Solid
    tailings sink to the bottom, and water on the surface
    returns to the mine to be used again.
    Rather than build a tailings pond, Coeur Alaska pro
    poses to use Lower Slate Lake, located some three miles
    from the mine in the Tongass National Forest. This lake
    is small—800 feet at its widest crossing, 2,000 feet at its
    longest, and 23 acres in area. See App. 138a, 212a.
    Though small, the lake is 51 feet deep at its maximum.
    The parties agree the lake is a navigable water of the
    United States and so is subject to the CWA. They also
    agree there can be no discharge into the lake except as the
    CWA and any lawful permit allow.
    Over the life of the mine, Coeur Alaska intends to put
    4.5 million tons of tailings in the lake. This will raise the
    lakebed 50 feet—to what is now the lake’s surface—and
    will increase the lake’s area from 23 to about 60 acres. Id.,
    at 361a (62 acres), 212a (56 acres). To contain this wider,
    shallower body of water, Coeur Alaska will dam the lake’s
    downstream shore. The transformed lake will be isolated
    4        COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    from other surface water. Creeks and stormwater runoff
    will detour around it. Id., at 298a. Ultimately, lakewater
    will be cleaned by purification systems and will flow from
    the lake to a stream and thence onward. Id., at 309a–
    312a.
    B
    Numerous state and federal agencies reviewed and
    approved Coeur Alaska’s plans. At issue here are actions
    by two of those agencies: the Corps of Engineers and the
    EPA.
    1
    The CWA classifies crushed rock as a “pollutant.” 
    33 U.S. C
    . §1362(6). On the one hand, the Act forbids Coeur
    Alaska’s discharge of crushed rock “[e]xcept as in compli
    ance” with the Act. CWA §301(a), 
    33 U.S. C
    . §1311(a).
    Section 404(a) of the CWA, on the other hand, empowers
    the Corps to authorize the discharge of “dredged or fill
    material.” 
    33 U.S. C
    . §1344(a). The Corps and the EPA
    have together defined “fill material” to mean any “mate
    rial [that] has the effect of . . . [c]hanging the bottom ele
    vation” of water. 40 CFR §232.2. The agencies have
    further defined the “discharge of fill material” to include
    “placement of . . . slurry, or tailings or similar mining
    related materials.” Ibid.
    In these cases the Corps and the EPA agree that the
    slurry meets their regulatory definition of “fill material.”
    On that premise the Corps evaluated the mine’s plan for a
    §404 permit. After considering the environmental factors
    required by §404(b), the Corp issued Coeur Alaska a per
    mit to pump the slurry into Lower Slate Lake. App. 340a–
    378a.
    In granting the permit the Corps followed the steps set
    forth by §404. Section 404(b) requires the Corps to con
    sider the environmental consequences of every discharge it
    Cite as: 557 U. S. ____ (2009)           5
    Opinion of the Court
    allows. 
    33 U.S. C
    . §1344(b). The Corps must apply guide
    lines written by the EPA pursuant to §404(b). See ibid.;
    40 CFR pt. 230 (EPA guidelines). Applying those guide
    lines here, the Corps determined that Coeur Alaska’s plan
    to use Lower Slate Lake as a tailings pond was the “least
    environmentally damaging practicable” way to dispose of
    the tailings. App. 366a. To conduct that analysis, the
    Corps compared the plan to the proposed alternatives.
    The Corps determined that the environmental damage
    caused by placing slurry in the lake will be temporary.
    And during that temporary disruption, Coeur Alaska will
    divert waters around the lake through pipelines built for
    this purpose. Id., at 298a. Coeur Alaska will also treat
    water flowing from the lake into downstream waters,
    pursuant to strict EPA criteria. Ibid.; see Part I–B–2,
    infra. Though the slurry will at first destroy the lake’s
    small population of common fish, that population may
    later be replaced. After mining operations are completed,
    Coeur Alaska will help “recla[im]” the lake by “[c]apping”
    the tailings with about 4 inches of “native material.” App.
    361a; id., at 309a. The Corps concluded that
    “[t]he reclamation of the lake will result in more
    emergent wetlands/vegetated shallows with moderate
    values for fish habitat, nutrient recycling, car
    bon/detrital export and sediment/toxicant retention,
    and high values for wildlife habitat.” Id., at 361a.
    If the tailings did not go into the lake, they would be
    placed on nearby wetlands. The resulting pile would rise
    twice as high as the Pentagon and cover three times as
    many acres. Reply Brief for Petitioner Coeur Alaska 27.
    If it were chosen, that alternative would destroy dozens of
    acres of wetlands—a permanent loss. App. 365a–366a.
    On the premise that when the mining ends the lake will
    be at least as environmentally hospitable, if not more so,
    than now, the Corps concluded that placing the tailings in
    6        COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    the lake will cause less damage to the environment than
    storing them above ground: The reclaimed lake will be
    “more valuable to the aquatic ecosystem than a perma
    nently filled wetland . . . that has lost all aquatic functions
    and values.” Id., at 361a; see also id., at 366a.
    2
    The EPA had the statutory authority to veto the Corps
    permit, and prohibit the discharge, if it found the plan to
    have “an unacceptable adverse effect on municipal water
    supplies, shellfish beds and fishery areas . . . , wildlife, or
    recreational areas.” CWA §404(c), 
    33 U.S. C
    . §1344(c).
    After considering the Corps findings, the EPA did not veto
    the Corps permit, even though, in its view, placing the
    tailings in the lake was not the “environmentally prefer
    able” means of disposing of them. App. 300a. By declining
    to exercise its veto, the EPA in effect deferred to the judg
    ment of the Corps on this point.
    The EPA’s involvement extended beyond the agency’s
    veto consideration. The EPA also issued a permit of its
    own—not for the discharge from the mine into the lake but
    for the discharge from the lake into a downstream creek.
    Id., at 287a–331a. Section 402 grants the EPA authority
    to “issue a permit for the discharge of any pollutant,”
    “[e]xcept as provided in [CWA §404].”             
    33 U.S. C
    .
    §1342(a). The EPA’s §402 permit authorizes Coeur Alaska
    to discharge water from Lower Slate Lake into the down
    stream creek, subject to strict water-quality limits that
    Coeur Alaska must regularly monitor. App. 303a–304a,
    309a.
    The EPA’s authority to regulate this discharge comes
    from a regulation, termed a “new source performance
    standard,” that it has promulgated under authority
    granted to it by §306(b) of the CWA. Section 306(b) gives
    the EPA authority to regulate the amount of pollutants
    that certain categories of new sources may discharge into
    Cite as: 557 U. S. ____ (2009)           7
    Opinion of the Court
    the navigable waters of the United States. 
    33 U.S. C
    .
    §1316(b). Pursuant to this authority, the EPA in 1982
    promulgated a new source performance standard restrict
    ing discharges from new froth-flotation gold mines like
    Coeur Alaska’s. The standard is stringent: It allows “no
    discharge of process wastewater” from these mines. 40
    CFR §440.104(b)(1).
    Applying that standard to the discharge of water from
    Lower Slate Lake into the downstream creek, the EPA’s
    §402 permit sets strict limits on the amount of pollutants
    the water may contain. The permit requires Coeur Alaska
    to treat the water using “reverse osmosis” to remove alu
    minum, suspended solids, and other pollutants. App.
    298a; id., at 304a. Coeur Alaska must monitor the water
    flowing from the lake to be sure that the pollutants are
    kept to low, specified minimums. Id., at 326a–330a.
    C
    SEACC brought suit against the Corps of Engineers and
    various of its officials in the United States District Court
    for the District of Alaska. The Corps permit was not in
    accordance with law, SEACC argued, for two reasons.
    First, in SEACC’s view, the permit was issued by the
    wrong agency—Coeur Alaska ought to have sought a §402
    permit from the EPA, just as the company did for the
    discharge of water from the lake into the downstream
    creek. See Part I–B–2, supra. Second, SEACC contended
    that regardless of which agency issued the permit, the
    discharge itself is unlawful because it will violate the EPA
    new source performance standard for froth-flotation gold
    mines. (This is the same performance standard described
    above, which the EPA has already applied to the discharge
    of water from the lake into the downstream creek. See
    ibid.) SEACC argued that this performance standard also
    applies to the discharge of slurry into the lake. It con
    tended further that the performance standard is a binding
    8        COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    implementation of §306. Section 306(e) of the CWA makes
    it “unlawful” for Coeur Alaska to “operate” the mine “in
    violation of” the EPA’s performance standard. 
    33 U.S. C
    .
    §1316(e).
    Coeur Alaska and the State of Alaska intervened as
    defendants. Both sides moved for summary judgment.
    The District Court granted summary judgment in favor of
    the defendants.
    The Court of Appeals for the Ninth Circuit reversed and
    ordered the District Court to vacate the Corps of Engi
    neers’ permit. Southeast Alaska Conservation Council v.
    United States Army Corps of Engs., 
    486 F.3d 638
    , 654–
    655 (2007). The court acknowledged that Coeur Alaska’s
    slurry “facially meets the Corps’ current regulatory defini
    tion of ‘fill material,’ ” id., at 644, because it would have
    the effect of raising the lake’s bottom elevation. But the
    court also noted that the EPA’s new source performance
    standard “prohibits discharges from froth-flotation mills.”
    Ibid. The Court of Appeals concluded that “[b]oth of the
    regulations appear to apply in this case, yet they are at
    odds.” Ibid. To resolve the conflict, the court turned to
    what it viewed as “the plain language of the Clean Water
    Act.” Ibid. The court held that the EPA’s new source
    performance standard “applies to discharges from the
    froth-flotation mill at Coeur Alaska’s Kensington Gold
    Mine into Lower Slate Lake.” Ibid.
    In addition to the text of the CWA, the Court of Appeals
    also relied on the agencies’ statements made when prom
    ulgating their current and prior definitions of “fill mate
    rial.” These statements, in the Court of Appeals’ view,
    demonstrated the agencies’ intent that the EPA’s new
    source performance standard govern discharges like Coeur
    Alaska’s. Id., at 648–654.
    The Court of Appeals concluded that Coeur Alaska
    required a §402 permit for its slurry discharge, that the
    Corps lacked authority to issue such a permit under §404,
    Cite as: 557 U. S. ____ (2009)           9
    Opinion of the Court
    and that the proposed discharge was unlawful because it
    would violate the EPA new source performance standard
    and §306(e).
    The decision of the Court of Appeals in effect reallocated
    the division of responsibility that the Corps and the EPA
    had been following. The Court granted certiorari. 554
    U. S. ___ (2008). We now hold that the decision of the
    Court of Appeals was incorrect.
    II
    The question of which agency has authority to consider
    whether to permit the slurry discharge is our beginning
    inquiry. We consider first the authority of the EPA and
    second the authority of the Corps. Our conclusion is that
    under the CWA the Corps had authority to determine
    whether Coeur Alaska was entitled to the permit govern
    ing this discharge.
    A
    Section 402 gives the EPA authority to issue “permit[s]
    for the discharge of any pollutant,” with one important
    exception: The EPA may not issue permits for fill material
    that fall under the Corps’ §404 permitting authority.
    Section 402(a) states:
    “Except as provided in . . . [CWA §404, 
    33 U.S. C
    .
    §1344], the Administrator may . . . issue a permit for
    the discharge of any pollutant, . . . notwithstanding
    [CWA §301(a), 
    33 U.S. C
    . §1311(a)], upon condition
    that such discharge will meet either (A) all applicable
    requirements under [CWA §301, 
    33 U.S. C
    . §1311(a);
    CWA §302, 
    33 U.S. C
    . §1312; CWA §306, 
    33 U.S. C
    .
    §1316; CWA §307, 
    33 U.S. C
    . §1317; CWA §308, 
    33 U.S. C
    . §1318; CWA §403, 
    33 U.S. C
    . §1343], or (B)
    prior to the taking of necessary implementing actions
    relating to all such requirements, such conditions as
    the Administrator determines are necessary to carry
    10       COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    out the provisions of this chapter.”       
    33 U.S. C
    .
    §1342(a)(1) (emphasis added).
    Section 402 thus forbids the EPA from exercising permit
    ting authority that is “provided [to the Corps] in” §404.
    This is not to say the EPA has no role with respect to
    the environmental consequences of fill. The EPA’s func
    tion is different, in regulating fill, from its function in
    regulating other pollutants, but the agency does exercise
    some authority. Section 404 assigns the EPA two tasks in
    regard to fill material. First, the EPA must write guide
    lines for the Corps to follow in determining whether to
    permit a discharge of fill material. CWA §404(b); 
    33 U.S. C
    . §1344(b). Second, the Act gives the EPA authority
    to “prohibit” any decision by the Corps to issue a permit
    for a particular disposal site. CWA §404(c); 
    33 U.S. C
    .
    §1344(c). We, and the parties, refer to this as the EPA’s
    power to veto a permit.
    The Act is best understood to provide that if the Corps
    has authority to issue a permit for a discharge under §404,
    then the EPA lacks authority to do so under §402.
    Even if there were ambiguity on this point, the EPA’s
    own regulations would resolve it. Those regulations pro
    vide that “[d]ischarges of dredged or fill material into
    waters of the United States which are regulated under
    section 404 of CWA” “do not require [§402] permits” from
    the EPA. 40 CFR §122.3.
    In SEACC’s view, this regulation implies that some “fill
    material” discharges are not regulated under §404—else,
    SEACC asks, why would the regulation lack a comma
    before the word “which,” and thereby imply that only a
    subset of “discharges of . . . fill material” are “regulated
    under section 404.” Ibid.
    The agencies, however, have interpreted this regulation
    otherwise. In the agencies’ view the regulation essentially
    restates the text of §402, and forbids the EPA from issuing
    Cite as: 557 U. S. ____ (2009)           11
    Opinion of the Court
    permits for discharges that “are regulated under section
    404.” 40 CFR §122.3(b); cf. CWA §402(a) (“[e]xcept as
    provided in . . . [§404], the Administrator may . . . issue a
    permit”). Before us, the EPA confirms this reading of the
    regulation. Brief for Federal Respondents 27. The
    agency’s interpretation is not “plainly erroneous or incon
    sistent with the regulation”; and so we accept it as correct.
    Auer v. Robbins, 
    519 U.S. 452
    , 461 (1997) (internal quota
    tion marks omitted).
    The question whether the EPA is the proper agency to
    regulate the slurry discharge thus depends on whether the
    Corps of Engineers has authority to do so. If the Corps
    has authority to issue a permit, then the EPA may not do
    so. We turn to the Corps’ authority under §404.
    B
    Section 404(a) gives the Corps power to “issue per
    mits . . . for the discharge of dredged or fill material.” 
    33 U.S. C
    . §1344(a). As all parties concede, the slurry meets
    the definition of fill material agreed upon by the agencies
    in a joint regulation promulgated in 2002. That regulation
    defines “fill material” to mean any “material [that] has the
    effect of . . . [c]hanging the bottom elevation” of water—a
    definition that includes “slurry, or tailings or similar
    mining-related materials.” 40 CFR §232.2.
    SEACC concedes that the slurry to be discharged meets
    the regulation’s definition of fill material. Brief for Re
    spondent SEACC et al. 20. Its concession on this point is
    appropriate because slurry falls well within the central
    understanding of the term “fill,” as shown by the examples
    given by the regulation. See 40 CFR §232.2 (“Examples of
    such fill material include, but are not limited to: rock,
    sand, soil, clay . . . .”). The regulation further excludes
    “trash or garbage” from its definition. Ibid. SEACC ex
    presses a concern that Coeur Alaska’s interpretation of the
    statute will lead to §404 permits authorizing the dis
    12       COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    charges of other solids that are now restricted by EPA
    standards. Brief for Respondent SEACC et al. 44–45
    (listing, for example, “feces and uneaten feed,” “ litter, ”
    and waste produced in “battery manufacturing”). But
    these extreme instances are not presented by the cases
    now before us. If, in a future case, a discharger of one of
    these solids were to seek a §404 permit, the dispositive
    question for the agencies would be whether the solid at
    issue—for instance, “feces and uneaten feed”—came
    within the regulation’s definition of “fill.” SEACC cites no
    instance in which the agencies have so interpreted their
    fill regulation. If that instance did arise, and the agencies
    were to interpret the fill regulation as SEACC fears, then
    SEACC could challenge that decision as an unlawful
    interpretation of the fill regulation; or SEACC could claim
    that the fill regulation as interpreted is an unreasonable
    interpretation of §404. The difficulties are not presented
    here, however, because the slurry meets the regulation’s
    definition of fill.
    Rather than challenge the agencies’ decision to define
    the slurry as fill, SEACC instead contends that §404
    contains an implicit exception. According to SEACC, §404
    does not authorize the Corps to permit a discharge of fill
    material if that material is subject to an EPA new source
    performance standard.
    But §404’s text does not limit its grant of power in this
    way. Instead, §404 refers to all “fill material” without
    qualification.      Nor do the EPA regulations support
    SEACC’s reading of §404. The EPA has enacted guide
    lines, pursuant to §404(b), to guide the Corps permitting
    decision. 40 CFR pt. 230. Those guidelines do not strip
    the Corps of power to issue permits for fill in cases where
    the fill is also subject to an EPA new source performance
    standard.
    SEACC’s reading of §404 would create numerous diffi
    culties for the regulated industry. As the regulatory re
    Cite as: 557 U. S. ____ (2009)          13
    Opinion of the Court
    gime stands now, a discharger must ask a simple ques
    tion—is the substance to be discharged fill material or
    not? The fill regulation, 40 CFR §232.2, offers a clear
    answer to that question; and under the agencies’ view,
    that answer decides the matter—if the discharge is fill,
    the discharger must seek a §404 permit from the Corps; if
    not, only then must the discharger consider whether any
    EPA performance standard applies, so that the discharger
    requires a §402 permit from the EPA.
    Under SEACC’s interpretation, however, the discharger
    would face a more difficult problem. The discharger would
    have to ask—is the fill material also subject to one of the
    many hundreds of EPA performance standards, so that
    the permit must come from the EPA, not the Corps? The
    statute gives no indication that Congress intended to
    burden industry with that confusing division of permit
    authority.
    The regulatory scheme discloses a defined, and worka
    ble, line for determining whether the Corps or the EPA
    has the permit authority. Under this framework, the
    Corps of Engineers, and not the EPA, has authority to
    permit Coeur Alaska’s discharge of the slurry.
    III
    A second question remains: In issuing the permit did the
    Corps act in violation of a statutory mandate so that the
    issuance was “not in accordance with law”? 
    5 U.S. C
    .
    §706(2)(A). SEACC contends that the slurry discharge
    will violate the EPA’s new source performance standard
    and that the Corps permit is made “unlawful” by CWA
    §306(e). Petitioners and the agencies argue that the per
    mit is lawful because the EPA performance standard, and
    §306(e), do not apply to fill material regulated by the
    Corps. In order to determine whether the Corps permit is
    lawful we must answer the question: Do EPA performance
    standards, and §306(e), apply to discharges of fill mate
    14      COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    rial?
    We address in turn the statutory text of the CWA, the
    agencies’ regulations construing it, and the EPA’s subse
    quent interpretation of those regulations. Because Con
    gress has not “directly spoken” to the “precise question” of
    whether an EPA performance standard applies to dis
    charges of fill material, the statute alone does not resolve
    the case. Chevron U. S. A. Inc. v. Natural Resources De
    fense Council, Inc., 
    467 U.S. 837
    , 842 (1984). We look
    first to the agency regulations, which are entitled to defer
    ence if they resolve the ambiguity in a reasonable manner.
    Ibid.; see United States v. Mead Corp., 
    533 U.S. 218
    , 226–
    227 (2001). But the regulations, too, are ambiguous, so we
    next turn to the agencies’ subsequent interpretation of
    those regulations. Id., at 234–238; Auer, 519 U. S., at 461.
    In an internal memorandum the EPA explained that its
    performance standards do not apply to discharges of fill
    material. That interpretation is not “plainly erroneous or
    inconsistent with the regulation[s],” and so we accept it as
    correct. Ibid. (internal quotation marks omitted). Though
    SEACC contends that the agencies’ interpretation is not
    entitled to deference because it contradicts the agencies’
    published statements and prior practice, we disagree with
    SEACC’s reading of those statements and of the regula
    tory record.
    A
    As for the statutory argument, SEACC claims the CWA
    §404 permit is unlawful because §306(e) forbids the slurry
    discharge. Petitioners and the federal agencies, in con
    trast, contend that §306(e) does not apply to the slurry
    discharge.
    1
    To address SEACC’s statutory argument, it is necessary
    to review the EPA’s responsibilities under the CWA. As
    Cite as: 557 U. S. ____ (2009)           15
    Opinion of the Court
    noted, §306 empowers the EPA to regulate the froth
    flotation gold mining industry. See 
    33 U.S. C
    . §1316(b).
    Pursuant to this authority, EPA promulgated the new
    source performance standard relied upon by SEACC. The
    standard is stringent. If it were to apply here, it would
    allow “no discharge of process wastewater” from the mine.
    40 CFR §440.104(b)(1).
    The term “process wastewater” includes solid waste. So
    the regulation forbids not only pollutants that dissolve in
    water but also solid pollutants suspended in water—what
    the agency terms “total suspended solids,” or TSS. See
    §440.104(a) (limiting the amount of TSS from other kinds
    of mines); see also EPA Development Document for Efflu
    ent Limitations Guidelines and Standards for the Ore
    Mining and Dressing Point Source Category 157–158
    (Nov. 1982) (the amount of TSS in “wastewater” from
    froth-flotation mines is “generally high”); id., at 175 (Table
    VI–6) (measuring the amounts of TSS in samples of froth
    flotation mines’ discharges); id., at 194 (stating an intent
    to “regulat[e]” TSS); id., at 402 (evaluating the costs of
    constructing a “settling pond”); id., at 535 (concluding that
    even in mountainous regions, a froth-flotation mine will be
    able to construct a “tailings impoundment” to “provide a
    disposal area for mill tailings”).
    Were there any doubt about whether the EPA’s new
    source performance standard forbade solids as well as
    soluble pollutants, the agency’s action in these cases
    would resolve it. Here, the EPA’s §402 permit authorizes
    Coeur Alaska to discharge water from Lower Slate Lake
    into a downstream creek, provided the water meets the
    quality requirements set by the performance standard.
    This demonstrates that the performance standard regu
    lates solid waste. The EPA’s permit not only restricts the
    amount of total suspended solids, App. 327a (Table 3), but
    also forbids the mine from allowing any “floating solids” to
    flow from the lake. Id., at 328a. No party disputes the
    16       COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    EPA’s authority to regulate these discharges of solid min
    ing waste; and no party questions the validity of the EPA’s
    new source performance standard when it is applicable.
    When the performance standard applies to a point
    source, §306(e) makes it “unlawful” for that point source to
    violate it: “[I]t shall be unlawful for any owner or operator
    of any new source to operate such source in violation of
    any standard of performance applicable to such source.”
    CWA §306(e), 
    33 U.S. C
    . §1316(e).
    SEACC argues that this provision, §306(e), forbids the
    mine from discharging slurry into Lower Slate Lake.
    SEACC contends the new source performance standard is,
    in the words of §306(e), “applicable to” the mine. Both the
    text of the performance standard and the EPA’s applica
    tion of it to the discharge of mining waste from Lower
    Slate Lake demonstrate that the performance standard is
    “applicable to” Coeur Alaska’s mine in some circum
    stances. And so, SEACC reasons, it follows that because
    the new source performance standard forbids even minute
    discharges of solid waste, it also forbids the slurry dis
    charge, 30% of which is solid waste.
    2
    For their part, the State of Alaska and the federal agen
    cies claim that the Act is unambiguous in the opposite
    direction. They rely on §404 of the Act. As explained
    above, that section authorizes the Corps of Engineers to
    determine whether to issue a permit allowing the dis
    charge of the slurry. Petitioners and the agencies argue
    that §404 grants the Corps authority to do so without
    regard to the EPA’s new source performance standard or
    the §306(e) prohibition discussed above.
    Petitioners and the agencies make two statutory argu
    ments based on §404’s silence in regard to §306. First,
    they note that nothing in §404 requires the Corps to con
    sider the EPA’s new source performance standard or the
    Cite as: 557 U. S. ____ (2009)          17
    Opinion of the Court
    §306(e) prohibition. That silence advances the argument
    that §404’s grant of authority to “issue permits” contra
    dicts §306(e)’s declaration that discharges in violation of
    new source performance standards are “unlawful.”
    Second, petitioners and the agencies point to §404(p),
    which protects §404 permitees from enforcement actions
    by the EPA or private citizens:
    “Compliance with a permit issued pursuant to this
    section . . . shall be deemed compliance, for purposes
    of sections 1319 [CWA §309] and 1365 [CWA §505] of
    this title, with sections 1311 [CWA §301], 1317 [CWA
    §307], and 1343 [CWA §403] of this title.” 
    33 U.S. C
    .
    §1344(p).
    Here again, their argument is that silence is significant.
    Section 404(p) protects the permitee from lawsuits alleg
    ing violations of CWA §301 (which bars the discharge of
    “any pollutant” “except as in compliance” with the Act),
    §307 (which bars the discharge of “toxic pollutants”); and
    §403 (which bars discharges into the sea). But §404(p)
    does not in express terms protect the permitee from a
    lawsuit alleging a violation of §306(e) or of the EPA’s new
    source performance standards. Section 404(p)’s silence
    regarding §306 is made even more significant because a
    parallel provision in §402 does protect a §402 permitee
    from an enforcement action alleging a violation of §306.
    CWA §402(k), 
    33 U.S. C
    . §1342(k).
    In our view, Congress’ omission of §306 from §404, and
    its inclusion of §306 in §402(k), is evidence that Congress
    did not intend §306(e) to apply to Corps §404 permits or to
    discharges of fill material. If §306 did apply, then the
    Corps would be required to evaluate each permit applica
    tion for compliance with §306, and issue a permit only if it
    found the discharge would comply with §306. But even if
    that finding were made, it is not clear that the §404 per
    mitee would be protected from a suit seeking a judicial
    18      COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    determination that the discharge violates §306.
    3
    The CWA is ambiguous on the question whether §306
    applies to discharges of fill material regulated under §404.
    On the one hand, §306 provides that a discharge that
    violates an EPA new source performance standard is
    “unlawful”—without any exception for fill material. On
    the other hand, §404 grants the Corps blanket authority to
    permit the discharge of fill material—without any mention
    of §306. This tension indicates that Congress has not
    “directly spoken” to the “precise question” of whether §306
    applies to discharges of fill material. Chevron, 467 U. S.,
    at 842.
    B
    Before turning to how the agencies have resolved that
    question, we consider the formal regulations that bear on
    §§306 and 404. See Mead, 533 U. S., at 234–238. The
    regulations, like the statutes, do not address the question
    whether §306, and the EPA new source performance stan
    dards promulgated under it, apply to §404 permits and the
    discharges they authorize. There is no regulation, for
    example, interpreting §306(e)’s text—“standard of per
    formance applicable to such source”—to mean that a
    performance standard ceases to be “applicable” the mo
    ment the discharge qualifies as fill material, which would
    resolve the cases in petitioners’ favor. Nor is there a
    regulation providing that the Corps, in deciding whether
    to grant a permit under §404, must deny that permit if the
    discharge would violate §306(e), which would decide the
    cases for SEACC.
    Rather than address the tension between §§306 and
    404, the regulations instead implement the statutory
    framework without elaboration on this point. Each of the
    two principal regulations, which have been mentioned
    above, seems to stand on its own without reference to the
    Cite as: 557 U. S. ____ (2009)           19
    Opinion of the Court
    other. The EPA’s new source performance standard con
    tains no exception for fill material; and it forbids any
    discharge of “process wastewater,” a term that includes
    solid wastes. 40 CFR §440.104(b)(1); see Part III–A–1,
    supra. The agencies’ joint regulation defining fill material
    is also unqualified. It includes “slurry, or tailings or simi
    lar mining-related materials” in its definition of a “dis
    charge of fill material,” 40 CFR §232.2; and it contains no
    exception for slurry that is regulated by an EPA perform
    ance standard.
    The parties point to additional regulations, but these
    provisions do not offer a clear basis of reconciliation. An
    EPA regulation, mentioned above, provides that
    “[d]ischarges of dredged or fill material into waters of the
    United States which are regulated under section 404 of
    CWA” “do not require [§402] permits” from the EPA.
    §122.3. As we have explained, however, this merely states
    that a permit for this discharge cannot be issued by the
    EPA. See Part II, supra. The regulation does not answer
    the question whether the EPA’s new source performance
    standard, and §306(e), apply to a discharge regulated by
    the Corps under §404.
    The agencies also direct us to the §404(b) guidelines
    written by the EPA to guide the Corps permitting decision.
    See 40 CFR pt. 230. The agencies note that these guide
    lines do not expressly require the Corps, in issuing a
    permit, to consider whether the discharge would violate
    EPA’s performance standards. Here we think failure to
    mention §306 or the EPA new source performance stan
    dards does offer some indication that these are not rele
    vant to the §404 permit, though the argument falls short
    of being conclusive. The Corps’ own regulations require
    the agency to evaluate permit applications “for compliance
    with applicable [EPA] effluent limitations.” 33 CFR
    §320.4(d) (2008). The regulations do not answer whether
    the new source performance standard is “applicable” to a
    20       COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    discharge of fill material.
    C
    The regulations do not give a definitive answer to the
    question whether §306 applies to discharges regulated by
    the Corps under §404, but we do find that agency interpre
    tation and agency application of the regulations are in
    structive and to the point. Auer, 519 U. S., at 461. The
    question is addressed and resolved in a reasonable and
    coherent way by the practice and policy of the two agen
    cies, all as recited in a memorandum written in May 2004
    by Diane Regas, then the Director of the EPA’s Office of
    Wetlands, Oceans and Watersheds, to Randy Smith, the
    Director of the EPA’s regional Office of Water with re
    sponsibility over the mine. App. 141a–149a (Regas Memo
    randum). The Memorandum, though not subject to suffi
    ciently formal procedures to merit Chevron deference, see
    Mead, supra, at 234–238, is entitled to a measure of defer
    ence because it interprets the agencies’ own regulatory
    scheme. See Auer, supra, at 461.
    The Regas Memorandum explains:
    “As a result [of the fact that the discharge is regulated
    under §404], the regulatory regime applicable to dis
    charges under section 402, including effluent limita
    tions guidelines and standards, such as those applica
    ble to gold ore mining . . . do not apply to the
    placement of tailings into the proposed impoundment
    [of Lower Slate Lake]. See 40 CFR §122.3(b).” App.
    144a–145a.
    The regulation that the Memorandum cites—40 CFR
    §122.3—is one we considered above and found ambiguous.
    That regulation provides: “[d]ischarges of dredged or fill
    material into waters of the United States which are regu
    lated under section 404 of CWA” “do not require [§402]
    permits.” The Regas Memorandum takes an instructive
    Cite as: 557 U. S. ____ (2009)          21
    Opinion of the Court
    interpretive step when it explains that because the dis
    charge “do[es] not require” an EPA permit, ibid., the
    EPA’s performance standard “do[es] not apply” to the
    discharge. App. 145a. The Memorandum presents a
    reasonable interpretation of the regulatory regime. We
    defer to the interpretation because it is not “plainly erro
    neous or inconsistent with the regulation[s].” Auer, supra,
    at 461 (internal quotation marks omitted). Five factors
    inform that conclusion.
    First, the Memorandum preserves a role for the EPA’s
    performance standard. It confines the Memorandum’s
    scope to closed bodies of water, like the lake here. App.
    142a–143a, n. 1. When slurry is discharged into a closed
    body of water, the Memorandum explains, the EPA’s
    performance standard retains an important role in regu
    lating the discharge into surrounding waters. The Memo
    randum does not purport to invalidate the EPA’s perform
    ance standard.
    Second, the Memorandum acknowledges that this is not
    an instance in which the discharger attempts to evade the
    requirements of the EPA’s performance standard. The
    Kensington Mine is not, for example, a project that smug
    gles a discharge of EPA-regulated pollutants into a sepa
    rate discharge of Corps-regulated fill material. The in
    stant cases do not present a process or plan designed to
    manipulate the outer boundaries of the definition of “fill
    material” by labeling minute quantities of EPA-regulated
    solids as fill. The Memorandum states that when a dis
    charge has only an “incidental filling effect,” the EPA’s
    performance standard continues to govern that discharge.
    Id., at 145a.
    Third, the Memorandum’s interpretation preserves the
    Corps’ authority to determine whether a discharge is in
    the public interest. See 33 CFR §320.4(a)(1); 40 CFR
    §230.10. The Corps has significant expertise in making
    this determination. Applying it, the Corps determined
    22      COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    that placing slurry in the lake will improve that body of
    water by making it wider, shallower, and so more capable
    of sustaining aquatic life. The Corps determined, fur
    thermore, that the alternative—a heap of tailings larger
    than the Pentagon placed upon wetlands—would cause
    more harm to the environment. Because the Memoran
    dum preserves an important role for the Corps’ expertise,
    its conclusion that the EPA’s performance standard does
    not apply is a reasonable one.
    Fourth, the Regas Memorandum’s interpretation does
    not allow toxic pollutants (as distinguished from other,
    less dangerous pollutants, such as slurry) to enter the
    navigable waters. The EPA has regulated toxic pollutants
    under a separate provision, §307 of the CWA, and the
    EPA’s §404(b) guidelines require the Corps to deny a §404
    permit for any discharge that would violate the EPA’s
    §307 toxic-effluent limitations. 40 CFR §230.10(b)(2).
    Fifth, as a final reason to defer to the Regas Memoran
    dum, we find it a sensible and rational construction that
    reconciles §§306, 402, and 404, and the regulations im
    plementing them, which the alternatives put forward by
    the parties do not. SEACC’s argument, that §402 applies
    to this discharge and not §404, is not consistent with the
    statute and regulations, as already noted. See Part II,
    supra.
    The Court requested the parties to submit supplemental
    briefs addressing whether the CWA contemplated that
    both agencies would issue a permit for a discharge. 556
    U. S. ___ (2009). A two-permit regime would allow the
    EPA to apply its performance standard, while the Corps
    could apply its §404(b) criteria. The parties agree, how
    ever, that a two-permit regime is contrary to the statute
    and the regulations. We conclude that this is correct. A
    two-permit regime would cause confusion, delay, expense,
    and uncertainty in the permitting process. In agreement
    with all of the parties, we conclude that, when a permit is
    Cite as: 557 U. S. ____ (2009)           23
    Opinion of the Court
    required to discharge fill material, either a §402 or a §404
    permit is necessary. Here, we now hold, §404 applies, not
    §402. See Part II, supra.
    The Regas Memorandum’s interpretation of the agen
    cies’ regulations is consistent with the regulatory scheme
    as a whole. The Memorandum preserves a role for the
    EPA’s performance standards; it guards against the possi
    bility of evasion of those standards; it employs the Corps’
    expertise in evaluating the effects of fill material on the
    aquatic environment; it does not allow toxic pollutants to
    be discharged; and we have been offered no better way to
    harmonize the regulations. We defer to the EPA’s conclu
    sion that its performance standard does not apply to the
    initial discharge of slurry into the lake but applies only to
    the later discharge of water from the lake into the down
    stream creek.
    D
    SEACC argues against deference to the Regas Memo
    randum. In its view the Regas Memorandum is contrary
    to published agency statements and earlier agency prac
    tice. SEACC cites three agency statements: A 1986
    “memorandum of understanding” between the EPA and
    the Corps regarding the definition of fill material; the
    preamble to the agencies’ current 2002 fill regulation; and
    comments made by the agencies in promulgating the 2002
    fill regulation. These arguments are not convincing.
    1
    In 1986, to reconcile their then-differing definitions of
    “fill material,” the EPA and the Corps issued a “memoran
    dum of agreement.” 51 Fed. Reg. 8871 (MOA). The
    memorandum was not made subject to notice-and
    comment procedures, but it was published in the Federal
    Register. It defined the statutory term “fill material” until
    the current definition took effect in 2002. Brief for Fed
    24       COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    eral Respondents 30–31, n. 8.
    SEACC points to paragraph B(5) of the MOA, which
    reads:
    “[A] pollutant (other than dredged material) will nor
    mally be considered by EPA and the Corps to be sub
    ject to section 402 if it is a discharge in liquid, semi
    liquid, or suspended form or if it is a discharge of solid
    material of a homogeneous nature normally associ
    ated with single industry wastes . . . . These materials
    include placer mining wastes, phosphate mining
    wastes, titanium mining wastes, sand and gravel
    wastes, fly ash, and drilling muds. As appropriate,
    EPA and the Corps will identify additional such mate
    rials.” 51 Fed. Reg. 8872.
    It is true, as SEACC notes, that this passage suggests that
    §402 will “normally” apply to discharges of “suspended”—
    i.e., solid—pollutants. But that statement is not contrary
    to the Regas Memorandum, which acknowledges that the
    EPA retains authority under §402 to regulate the dis
    charge of suspended solids from Lower Slate Lake into
    downstream waters. This passage does not address the
    question presented by these cases, and answered by the
    Regas Memorandum, as to whether the EPA’s perform
    ance standard applies when the discharge qualifies as fill
    material. In fact, the MOA’s preamble suggests that when
    a discharge qualifies as “fill material,” the Corps retains
    authority to regulate it under §404:
    “Discharges listed in the Corps definition of ‘discharge
    of fill material,’ . . . remain subject to section 404 even
    if they occur in association with discharges of wastes
    meeting the criteria in the agreement for section 402
    discharges.” Id., at 8871.
    The MOA is quite consistent with the agencies’ determi
    nation that the Corps regulates all discharges of fill mate
    Cite as: 557 U. S. ____ (2009)           25
    Opinion of the Court
    rial and that §306 does not apply to these discharges.
    2
    SEACC draws our attention to the preamble of the
    current fill material regulation. 67 Fed. Reg. 31129 (2002)
    (final rule). It cites the opening passages of the preamble,
    which state:
    “[T]oday’s rule is generally consistent with current
    agency practice and so it does not expand the types of
    discharges that will be covered under section 404.”
    Id., at 31133.
    In SEACC’s view, this passage demonstrates that the fill
    rule was not intended to displace the pre-existing froth
    flotation gold mine performance standard, which has been
    on the books since 1982.
    The preamble goes on to say, in a section entitled “Efflu
    ent Guideline Limitations and 402 Permits”:
    “[W]e emphasize that today’s rule generally is in
    tended to maintain our existing approach to regulat
    ing pollutants under either section 402 or 404 of the
    CWA. Effluent limitation guidelines and new source
    performance standards (‘effluent guidelines’) promul
    gated under section 304 and 306 of the CWA establish
    limitations and standards for specified wastestreams
    from industrial categories, and those limitations and
    standards are incorporated into permits issued under
    section 402 of the Act. EPA has never sought to regu
    late fill material under effluent guidelines. Rather,
    effluent guidelines restrict discharges of pollutants
    from identified wastestreams based upon the pollut
    ant reduction capabilities of available treatment tech
    nologies. Recognizing that some discharges (such as
    suspended or settleable solids) can have the associ
    ated effect, over time, of raising the bottom elevation
    of a water due to settling of waterborne pollutants, we
    26       COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    do not consider such pollutants to be ‘fill material,’
    and nothing in today’s rule changes that view. Nor
    does today’s rule change any determination we have
    made regarding discharges that are subject to an ef
    fluent limitation guideline and standards, which will
    continue to be regulated under section 402 of the
    CWA. Similarly, this rule does not alter the manner
    in which water quality standards currently apply un
    der the section 402 or the section 404 programs.” Id.,
    at 31135.
    Although the preamble asserts it does not change agency
    policy with regard to EPA performance standards and
    §402 permitting decisions, it is explicit in noting that the
    EPA has “never sought to regulate fill material under
    effluent guidelines.” Ibid. The preamble, then, is consis
    tent with the Regas Memorandum. If a discharge does not
    qualify as fill material, the EPA’s new source performance
    standard applies. If the discharge qualifies as fill, the
    performance standard does not apply; and there was no
    earlier agency practice or policy to the contrary.
    3
    SEACC also cites remarks made by the agencies in
    response to public comments on the proposed fill material
    regulation. App. 22a–127a. These remarks were incorpo
    rated by reference into the administrative record. 67 Fed.
    Reg. 31131.
    Responding to a question about whether “mine tailings”
    would be “subject to section 404 regulation as opposed to
    section 402” under the 2002 fill regulation, the agencies
    stated:
    “Today’s final rule clarifies that any material that has
    the effect of fill is regulated under section 404 and
    further that the placement of ‘overburden, slurry, or
    tailings or similar mining-related materials’ is consid
    Cite as: 557 U. S. ____ (2009)          27
    Opinion of the Court
    ered a discharge of fill material. Nevertheless, if EPA
    has previously determined that certain materials are
    subject to an [effluent limitation guideline] under spe
    cific circumstances, then that determination remains
    valid. Moreover, . . . permits issued pursuant to sec
    tion 402 are intended to regulate process water and
    provide effluent limits that are protective of receiving
    water quality. This distinction provides the frame
    work for today’s rule.” App. 48a.
    This statement is not conclusive of the issue. SEACC
    notes that this response, like the regulation’s preamble,
    pledges that EPA’s “previou[s] . . . determination[s]” with
    regard to the application of performance standards “re
    mai[n] valid.” But, as noted above, the Regas Memoran
    dum has followed this policy by applying the EPA’s per
    formance standard to the discharge of water from the lake
    into the downstream creek. The response does not state
    that the EPA will apply its performance standards to
    discharges of fill material.
    4
    The agencies’ published statements indicate adherence
    to the EPA’s previous application and interpretation of its
    performance standards. SEACC cannot show that the
    agencies have changed their interpretation or application
    of their regulations.
    SEACC cites no instance in which the EPA has applied
    one of its performance standards to a discharge of fill
    material. By contrast, Coeur Alaska cites two instances in
    which the Corps issued a §404 permit authorizing a mine
    to discharge solid waste (tailings) as fill material. See
    Brief for Petitioner Coeur Alaska 40–42. SEACC objects
    that those two §404 permits authorized discharges that
    used the tailings to construct useful structures—a dam in
    one case, a tailings pond in another. Here, by contrast,
    SEACC contends that the primary purpose of the dis
    28      COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of the Court
    charge is to use a navigable water to dispose of waste.
    Ibid. But that objection misses the point. The two §404
    permits cited by Coeur Alaska illustrate that the agencies
    did not have a prior practice of applying EPA performance
    standards to discharges of mining wastes that qualify as
    fill material.
    SEACC has not demonstrated that the agencies have
    changed their policy, and it cannot show that the Regas
    Memorandum is contrary to the agencies’ published
    statements.
    *    *   *
    We accord deference to the agencies’ reasonable decision
    to continue their prior practice.
    The judgment of the Court of Appeals is reversed, and
    these cases are remanded for further proceedings consis
    tent with this opinion.
    It is so ordered.
    Cite as: 557 U. S. ____ (2009)           1
    BREYER, J., concurring
    SUPREME COURT OF THE UNITED STATES
    _________________
    Nos. 07–984 and 07–990
    _________________
    COEUR ALASKA, INC., PETITIONER
    07–984              v.
    SOUTHEAST ALASKA CONSERVATION COUNCIL
    ET AL.
    ALASKA, PETITIONER
    07–990               v.
    SOUTHEAST ALASKA CONSERVATION COUNCIL
    ET AL.
    ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
    APPEALS FOR THE NINTH CIRCUIT
    [June 22, 2009]
    JUSTICE BREYER, concurring.
    As I understand the Court’s opinion, it recognizes a
    legal zone within which the regulating agencies might
    reasonably classify material either as “dredged or fill
    material” subject to §404 of the Clean Water Act, 
    33 U.S. C
    . §1344(a), or as a “pollutant,” subject to §§402 and
    306, 
    33 U.S. C
    . §§1342(a), 1316(a). Within this zone, the
    law authorizes the environmental agencies to classify
    material as the one or the other, so long as they act within
    the bounds of relevant regulations, and provided that the
    classification, considered in terms of the purposes of the
    statutes and relevant regulations, is reasonable.
    This approach reflects the difficulty of applying §§402
    and 306 literally to every new-source-related discharge of a
    “pollutant.” The Environmental Protection Agency (EPA)
    applies §306 new source “performance standards” to a
    wide variety of discharges, ranging, for example, from
    2        COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    BREYER, J., concurring
    those involved in the processing of apples into apple juice
    or apple cider, 40 CFR §407.10 (2008); to the manufactur
    ing of cement, §411.10; to the production of fresh meat
    cuts by a meat cutter, §432.60; and to the manufacture of
    pharmaceutical products by fermentation, §439.10. See
    generally 40 CFR pts. 405–471 (containing more than 800
    pages of “new source performance” and effluent limitation
    regulations). At the same time the regulations for any one
    point source often regulate numerous chemicals, minerals,
    and other substances produced by that point source; in the
    case of fermentation products, for example, the regulations
    provide performance standards for roughly 30 different
    chemicals. §439.15. These “standards of performance”
    “reflect the greatest degree of effluent reduction which the
    Administrator determines to be achievable through appli
    cation of the best available demonstrated control technol
    ogy . . . including, where practicable, a standard permit
    ting no discharge of pollutants.” 
    33 U.S. C
    . §1316(a)(1).
    To literally apply these performance standards so as to
    forbid the use of any of these substances as “fill,” even
    when, say, they constitute no more than trace elements in
    dirt, crushed rock, or sand that is clearly being used as
    “fill” to build a levee or to replace dirt removed from a lake
    bottom may prove unnecessarily strict, cf. §1362(6) (defin
    ing “pollutant” to include “rock”), to the point that such
    application would undermine the objective of §404, which
    foresees the use of “dredged or fill material” in certain
    circumstances and with approval of the relevant agencies.
    §1344. At minimum, the EPA might reasonably read the
    statute and the applicable regulations as allowing the use
    of such material, say crushed rock, as “fill” in some of
    these situations. Cf. Chevron U. S. A. Inc. v. Natural
    Resources Defense Council, Inc., 
    467 U.S. 837
    , 842–844
    (1984); Auer v. Robbins, 
    519 U.S. 452
    , 461 (1997).
    At the same time, I recognize the danger that JUSTICE
    GINSBURG warns against, namely, that “[w]hole categories
    Cite as: 557 U. S. ____ (2009)            3
    BREYER, J., concurring
    of regulated industries” might “gain immunity from a
    variety of pollution-control standards,” if, say, a §404
    permit applicant simply adds “sufficient solid matter” to a
    pollutant “to raise the bottom of a water body,” thereby
    turning a “pollutant” governed by §306 into “fill” governed
    by §404. Post, at 7 (dissenting opinion).
    Yet there are safeguards against that occurring. For
    one thing, as the Court recognizes, see ante, at 11, it is not
    the case that any material that has the “ ‘effect of . . .
    [c]hanging the bottom elevation’ ” of the body of water is
    automatically subject to §404, not §402. The EPA has
    never suggested that it would interpret the regulations so
    as to turn §404 into a loophole, permitting evasion of a
    “performance standard” simply because a polluter dis
    charges enough pollutant to raise the bottom elevation of
    the body of water. For another thing, even where a matter
    is determined reasonably to be “fill” and consequently falls
    within §404, the EPA can retain an important role in the
    permitting process. That is because the EPA may veto
    any §404 plan that it finds has an “unacceptable adverse
    effect on municipal water supplies, shellfish beds and
    fishery areas . . . , wildlife, or recreational areas.”
    §1344(c). Finally, EPA’s decision not to apply §306, but to
    allow permitting to proceed under §404, must be a reason
    able decision; and court review will help assure that is so.
    
    5 U.S. C
    . §706.
    In these cases, it seems to me that the EPA’s interpreta
    tion of the statute as permitting the EPA/Corps of Engi
    neers “fill” definition to apply to the cases at hand is rea
    sonable, hence lawful. Lower Slate Lake, located roughly
    three miles from the Kensington Gold Mine, is 51 feet
    deep, 800 feet wide, and 2,000 feet long; downstream from
    the lake is Slate Creek. Faced with a difficult choice
    between creating a huge pile of slurry on nearby wetlands
    or using part of the lake as a storage facility for mine
    tailings, see App. 294a–298a; see also ante, at 5–8, the
    4        COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    BREYER, J., concurring
    EPA arrived at a compromise. On the one hand, it would
    treat mine tailings placed directly into the lake as “fill”
    under the §404 permitting program. App. 144a. The
    tailings, the EPA recognized, would have the “immediate
    effect of filling the areas of water into which they are
    discharged.” Ibid. But it would also treat any spillover of
    the tailings, or chemicals from the tailings, into any
    nearby waterway, most particularly Slate Creek (running
    out of Slate Lake) as requiring a §402 permit. The EPA’s
    §306 “performance standard” would apply and that stan
    dard insists upon no discharge of process wastewater at
    all. Id., at 145a; see also 40 CFR §440.104(b). The EPA
    reached this result because it recognized that, even though
    pollutants discharged into the creek might come “in the
    form of suspended and settleable solids,” such solids would
    “have, at most, an incidental filling effect.” App. 145a.
    The EPA thereby sought to apply the distinction it had
    previously recognized between discharges that have the
    immediate effect of raising the bottom elevation of water,
    and those that only have the “associated effect, over time,
    of raising the bottom elevation of a water due to settling of
    waterborne pollutants.” See 67 Fed. Reg. 31135 (2002)
    (concluding that §402 applies to the latter); see also Brief
    for G. Tracy Mehan III as Amicus Curiae 22–23.
    I cannot say whether the EPA’s compromise represents
    the best overall environmental result; but I do believe it
    amounts to the kind of detailed decision that the statutes
    delegate authority to the EPA, not the courts, to make
    (subject to the bounds of reasonableness). I believe the
    Court’s views are consistent with those I here express.
    And with that understanding, I join its opinion.
    Cite as: 557 U. S. ____ (2009)            1
    Opinion of SCALIA, J.
    SUPREME COURT OF THE UNITED STATES
    _________________
    Nos. 07–984 and 07–990
    _________________
    COEUR ALASKA, INC., PETITIONER
    07–984              v.
    SOUTHEAST ALASKA CONSERVATION COUNCIL
    ET AL.
    ALASKA, PETITIONER
    07–990               v.
    SOUTHEAST ALASKA CONSERVATION COUNCIL
    ET AL.
    ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
    APPEALS FOR THE NINTH CIRCUIT
    [June 22, 2009]
    JUSTICE SCALIA, concurring in part and concurring in
    the judgment.
    I join the opinion of the Court, except for its protesta
    tion, ante, at 20, that it is not according Chevron deference
    to the reasonable interpretation set forth in the memoran
    dum sent by the Director of the Environmental Protection
    Agency’s (EPA) Office of Wetlands, Oceans and Water
    sheds, to the Director of the EPA’s regional Office of Water
    with responsibility over the Coeur Alaska mine—an inter
    pretation consistently followed by both EPA and the Corps
    of Engineers, and adopted by both agencies in the proceed
    ings before this Court. See Chevron U. S. A. Inc. v. Natu
    ral Resources Defense Council, Inc., 
    467 U.S. 837
     (1984).
    The opinion purports to give this agency interpretation “a
    measure of deference” because it involves an interpretation
    of “the agencies’ own regulatory scheme,” and “ ‘the regu-
    latory regime,’ ” ante, at 20 (citing Auer v. Robbins, 519
    2           COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    Opinion of SCALIA, J.
    U. S. 452, 461 (1997)). Auer, however, stands only for the
    principle that we defer to an agency’s interpretation of its
    own ambiguous regulation. But it becomes obvious from
    the ensuing discussion that the referenced “regulatory
    scheme,” and “regulatory regime” for which the Court
    accepts the agency interpretation includes not just the
    agencies’ own regulations but also (and indeed primarily)
    the conformity of those regulations with the ambiguous
    governing statute, which is the primary dispute here.
    Surely the Court is not adding to our already inscruta
    ble opinion in United States v. Mead Corp., 
    533 U.S. 218
    (2001), the irrational fillip that an agency position which
    otherwise does not qualify for Chevron deference does
    receive Chevron deference if it clarifies not just an am
    biguous statute but also an ambiguous regulation. One
    must conclude, then, that if today’s opinion is not accord
    ing the agencies’ reasonable and authoritative interpreta
    tion of the Clean Water Act Chevron deference, it is ac
    cording some new type of deference—perhaps to be called
    in the future Coeur Alaska deference—which is identical
    to Chevron deference except for the name.
    The Court’s deference to the EPA and the Corps of
    Engineers in today’s cases is eminently reasonable. It is
    quite impossible to achieve predictable (and relatively
    litigation-free) administration of the vast body of complex
    laws committed to the charge of executive agencies with
    out the assurance that reviewing courts will accept rea
    sonable and authoritative agency interpretation of am
    biguous provisions. If we must not call that practice
    Chevron deference, then we have to rechristen the rose.
    Of course the only reason a new name is required is our
    misguided opinion in Mead, whose incomprehensible
    criteria for Chevron deference have produced so much
    confusion in the lower courts* that there has now appeared
    ——————
    * Compare, e.g., Kruse v. Wells Fargo Home Mortgage, Inc., 383 F. 3d
    Cite as: 557 U. S. ____ (2009)                  3
    Opinion of SCALIA, J.
    the phenomenon of Chevron avoidance—the practice of
    declining to opine whether Chevron applies or not. See
    Bressman, How Mead Has Muddled Judicial Review of
    Agency Action, 58 Vand. L. Rev. 1443, 1464 (2005).
    I favor overruling Mead. Failing that, I am pleased to
    join an opinion that effectively ignores it.
    ——————
    49, 61 (CA2 2004) (according Chevron deference to policy statements
    issued by Department of Housing and Urban Development) and Schu
    etz v. Banc One Mortgage Corp., 
    292 F.3d 1004
    , 1012 (CA9 2002)
    (same), with Krzalic v. Republic Title Co., 
    314 F.3d 875
    , 881 (CA7
    2002) (denying Chevron deference to same policy statements). Compare
    American Federation of Govt. Employees, AFL–CIO, Local 446 v.
    Nicholson, 
    475 F.3d 341
    , 353–354 (CADC 2007) (according Chevron
    deference to informal adjudication by Department of Veterans Affairs),
    with American Federation of Govt. Employees, AFL–CIO, Local 2152 v.
    Principi, 
    464 F.3d 1049
    , 1057 (CA9 2006) (denying Chevron deference
    to similar action). It is not even clear that notice-and-comment rule
    making will assure Chevron deference to agency interpretation of an
    ambiguous statute. See Rubie’s Costume Co. v. United States, 
    337 F.3d 1350
    , 1355 (CA Fed. 2003) (customs classification).
    Cite as: 557 U. S. ____ (2009)                 1
    GINSBURG, J., dissenting
    SUPREME COURT OF THE UNITED STATES
    _________________
    Nos. 07–984 and 07–990
    _________________
    COEUR ALASKA, INC., PETITIONER
    07–984              v.
    SOUTHEAST ALASKA CONSERVATION COUNCIL
    ET AL.
    ALASKA, PETITIONER
    07–990               v.
    SOUTHEAST ALASKA CONSERVATION COUNCIL
    ET AL.
    ON WRITS OF CERTIORARI TO THE UNITED STATES COURT OF
    APPEALS FOR THE NINTH CIRCUIT
    [June 22, 2009]
    JUSTICE GINSBURG, with whom JUSTICE STEVENS and
    JUSTICE SOUTER join, dissenting.
    Petitioner Coeur Alaska, Inc., proposes to discharge
    210,000 gallons per day of mining waste into Lower Slate
    Lake, a 23-acre subalpine lake in Tongass National For
    est. The “tailings slurry” would contain concentrations of
    aluminum, copper, lead, and mercury. Over the life of the
    mine, roughly 4.5 million tons of solid tailings would enter
    the lake, raising the bottom elevation by 50 feet. It is
    undisputed that the discharge would kill all of the lake’s
    fish and nearly all of its other aquatic life.1
    Coeur Alaska’s proposal is prohibited by the Environ
    mental Protection Agency (EPA) performance standard
    ——————
    1 Whether  aquatic life will eventually be able to inhabit the lake
    again is uncertain. Compare ante, at 5, with App. 201a–202a; and
    Southeast Alaska Conservation Council v. United States Army Corps of
    Engineers, 
    486 F.3d 638
    , 642 (CA9 2007).
    2       COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    GINSBURG, J., dissenting
    forbidding any discharge of process wastewater from new
    “froth-flotation” mills into waters of the United States.
    See 40 CFR §440.104(b)(1) (2008). Section 306 of the
    Clean Water Act directs EPA to promulgate such perform
    ance standards, 
    33 U.S. C
    . §1316(a), and declares it
    unlawful for any discharger to violate them, §1316(e).
    Ordinarily, that would be the end of the inquiry.
    Coeur Alaska contends, however, that its discharge is
    not subject to EPA’s regulatory regime, but is governed,
    instead, by the mutually exclusive permitting authority of
    the Army Corps of Engineers. The Corps has authority,
    under §404 of the Act, §1344(a), to issue permits for dis
    charges of “dredged or fill material.” By regulation, a
    discharge that has the effect of raising a water body’s
    bottom elevation qualifies as “fill material.” See 33 CFR
    §323.2(e) (2008). Discharges properly within the Corps’
    permitting authority, it is undisputed, are not subject to
    EPA performance standards. See ante, at 20; Brief for
    Petitioner Coeur Alaska 26; Brief for Respondent South
    east Alaska Conservation Council et al. 37.
    The litigation before the Court thus presents a single
    question: Is a pollutant discharge prohibited under §306 of
    the Act eligible for a §404 permit as a discharge of fill
    material? In agreement with the Court of Appeals, I
    would answer no. The statute’s text, structure, and pur
    pose all mandate adherence to EPA pollution-control
    requirements. A discharge covered by a performance
    standard must be authorized, if at all, by EPA.
    I
    A
    Congress enacted the Clean Water Act in 1972 “to re
    store and maintain the chemical, physical, and biological
    integrity” of the waters of the United States. 
    33 U.S. C
    .
    §1251(a). “The use of any river, lake, stream or ocean as a
    waste treatment system,” the Act’s drafters stated, “is
    Cite as: 557 U. S. ____ (2009)                    3
    GINSBURG, J., dissenting
    unacceptable.” S. Rep. No. 92–414, p. 7 (1971). Congress
    announced in the Act itself an ambitious objective: to
    eliminate, by 1985, the discharge of all pollutants into the
    Nation’s navigable waters. 
    33 U.S. C
    . §1251(a).
    In service of its goals, Congress issued a core command:
    “[T]he discharge of any pollutant by any person shall be
    unlawful,” except in compliance with the Act’s terms.
    §1311(a). The Act’s substantive requirements—housed
    primarily in Subchapter III, “Standards and Enforce
    ment”—establish “a comprehensive regulatory program
    supervised by an expert administrative agency,” EPA.
    Milwaukee v. Illinois, 
    451 U.S. 304
    , 317 (1981). See also
    
    33 U.S. C
    . §1251(d) (“Except as otherwise expressly pro
    vided . . . , the Administrator of [EPA] shall administer
    this [Act].”).
    The Act instructs EPA to establish various technology
    based, increasingly stringent effluent limitations for cate
    gories of point sources. E.g., §§1311, 1314. These limita
    tions, formulated as restrictions “on quantities, rates, and
    concentrations of chemical, physical, biological, and other
    constituents,” §1362(11), were imposed to achieve national
    uniformity among categories of sources. See, e.g., E. I. du
    Pont de Nemours & Co. v. Train, 
    430 U.S. 112
    , 129–130
    (1977). The limitations for a given discharge depend on
    the type of pollutant and source at issue.2
    Of key importance, new sources must meet stringent
    “standards of performance” adopted by EPA under §306.
    That section makes it “unlawful for any . . . new source to
    operate . . . in violation of” an applicable performance
    ——————
    2 In addition, the Act requires States to institute comprehensive wa
    ter quality standards for intrastate waters, subject to EPA approval.
    See §1313. This program supplements the technology-based standards,
    serving to “prevent water quality from falling below acceptable levels”
    even when point sources comply with effluent limitations. EPA v.
    California ex rel. State Water Resources Control Bd., 
    426 U.S. 200
    , 205,
    n. 12 (1976).
    4         COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    GINSBURG, J., dissenting
    standard. 
    33 U.S. C
    . §1316(e) (emphasis added). In line
    with Congress’ aim “to insure . . .‘maximum feasible con
    trol of new sources,’ ” du Pont, 430 U. S., at 138, the pre
    ferred standard for a new source is one “ ‘permitting no
    discharge of pollutants,’ ” id., at 137–138 (quoting 
    33 U.S. C
    . §1316(a)(1) (emphasis added)). Moreover, new
    sources, unlike existing sources, are not eligible for EPA
    granted variances from applicable limitations. 430 U. S.,
    at 138.3
    In 1982, EPA promulgated new source performance
    standards for facilities engaged in mining, including those
    using a froth-flotation milling process. See Ore Mining
    and Dressing Point Source Category Effluent Limitations
    Guidelines and New Source Performance Standards, 47
    Fed. Reg. 54598 (1982). Existing mills, the Agency found,
    were already achieving zero discharge; it was therefore
    practicable, EPA concluded, for new mills to do as well.
    Id., at 54602. Accordingly, under 40 CFR §440.104(b)(1),
    new mines using the froth-flotation method, as Coeur
    Alaska proposes to do, may not discharge wastewater
    directly into waters of the United States.
    B
    The nationwide pollution-control requirements just
    described are implemented through the National Pollution
    Discharge Elimination System (NPDES), a permitting
    scheme set forth in §402 and administered by EPA and the
    States. The NPDES is the linchpin of the Act, for it trans
    forms generally applicable effluent limitations into the
    individual obligations of each discharger. EPA v. Califor
    ——————
    3 Even the provision allowing the President to exempt federal instal
    lations from compliance with the Act’s requirements—“if he determines
    it to be in the paramount interest of the United States to do so”—does
    not extend to new source standards: “[N]o exemption may be granted
    from the requirements of section [306] or [307] of this [Act].” 
    33 U.S. C
    . §1323(a).
    Cite as: 557 U. S. ____ (2009)            5
    GINSBURG, J., dissenting
    nia ex rel. State Water Resources Control Bd., 
    426 U.S. 200
    , 205 (1976). The discharge of a pollutant is generally
    prohibited unless the source has obtained a NPDES per
    mit. E.g., EPA v. National Crushed Stone Assn., 
    449 U.S. 64
    , 71 (1980) (“Section 402 authorizes the establishment of
    the [NPDES], under which every discharger of pollutants
    is required to obtain a permit.”).
    The Act also establishes a separate permitting scheme,
    administered by the Corps, for discharges of “dredged or
    fill material.” 
    33 U.S. C
    . §1344(a). Section 404 hews to
    the Corps’ established expertise in matters of navigability
    and construction. The §404 program does not implement
    the uniform, technology-based pollution-control standards
    set out, inter alia, in §306. Instead, §404 permits are
    subject to regulatory guidelines based generally on the
    impact of a discharge on the receiving environment. See
    §1344(b); ante, at 4–5.
    As the above-described statutory background indicates,
    Coeur Alaska’s claim to a §404 permit carries weighty
    implications. If eligible for that permit, Coeur Alaska can
    evade the exacting performance standard prescribed by
    EPA for froth-flotation mills. It may, instead, use Lower
    Slate Lake “as the settling pond and disposal site for the
    tailings.” App. 360a (Corps’ Record of Decision).
    II
    Is a pollutant discharge prohibited under §306(e) eligi
    ble to receive a §404 permit as a discharge of fill material?
    All agree on preliminary matters. Only one agency, the
    Corps or EPA, can issue a permit for the discharge. See
    ante, at 10, 22. Only EPA, through the NPDES program,
    issues permits that implement §306. See supra, at 2.
    Further, §306(e) and EPA’s froth-flotation performance
    standard, unless inapplicable here, bar Coeur Alaska’s
    proposed discharge. See ante, at 14–15.
    No part of the statutory scheme, in my view, calls into
    6        COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    GINSBURG, J., dissenting
    question the governance of EPA’s performance standard.
    The text of §306(e) states a clear proscription: “[I]t shall be
    unlawful for any owner or operator of any new source to
    operate such source in violation of any standard of per
    formance applicable to such source.” 
    33 U.S. C
    . §1316(e).
    Under the standard of performance relevant here, “there
    shall be no discharge of process wastewater to navigable
    waters from mills that use the froth-flotation process” for
    mining gold. 40 CFR §440.104(b)(1). The Act imposes
    these requirements without qualification.
    Section 404, stating that the Corps “may issue permits”
    for the discharge of “dredged or fill material,” does not
    create an exception to §306(e)’s plain command. 
    33 U.S. C
    . §1344(a). Cf. ante, at 12. Section 404 neither
    mentions §306 nor states a contrary requirement. The Act
    can be home to both provisions, with no words added or
    omitted, so long as the category of “dredged or fill mate
    rial” eligible for a §404 permit is read in harmony with
    §306. Doing so yields a simple rule: Discharges governed
    by EPA performance standards are subject to EPA’s ad
    ministration and receive permits under the NPDES, not
    §404.
    This reading accords with the Act’s structure and objec
    tives. It retains, through the NPDES, uniform application
    of the Act’s core pollution-control requirements, and it
    respects Congress’ special concern for new sources. Leav
    ing pollution-related decisions to EPA, moreover, is consis
    tent with Congress’ delegation to that agency of primary
    responsibility to administer the Act. Most fundamental,
    adhering to §306(e)’s instruction honors the overriding
    statutory goal of eliminating water pollution, and Con
    gress’ particular rejection of the use of navigable waters as
    waste disposal sites. See supra, at 2–3. See also 
    33 U.S. C
    . §1324 (creating “clean lakes” program requiring
    Cite as: 557 U. S. ____ (2009)                   7
    GINSBURG, J., dissenting
    States to identify and restore polluted lakes).4
    The Court’s reading, in contrast, strains credulity. A
    discharge of a pollutant, otherwise prohibited by firm
    statutory command, becomes lawful if it contains suffi
    cient solid matter to raise the bottom of a water body,
    transformed into a waste disposal facility. Whole catego
    ries of regulated industries can thereby gain immunity
    from a variety of pollution-control standards. The loophole
    would swallow not only standards governing mining ac
    tivities, see 40 CFR pt. 440 (effluent limitations and new
    source performance standards for ore mining and dress
    ing); id., pt. 434 (coal mining); id., pt. 436 (mineral min
    ing), but also standards for dozens of other categories of
    regulated point sources, see, e.g., id., pt. 411 (cement
    ——————
    4 The   Court asserts that “numerous difficulties” will ensue if a dis
    charge governed by a new source performance standard is ineligible for
    a §404 permit. Ante, at 12. Namely, the Court notes, the discharger
    will have to determine whether a performance standard applies to it.
    Ante, at 13. That is not only the usual inquiry under the Clean Water
    Act; it is one Coeur Alaska answered, without apparent difficulty, when
    it sought and obtained an EPA permit for the proposed discharge from
    the lake into a downstream creek. See ante, at 6.
    JUSTICE BREYER fears that “litera[l] appl[ication]” of performance
    standards would interfere with efforts “to build a levee or to replace
    dirt removed from a lake bottom,” and thus “may prove unnecessarily
    strict.” Ante, at 2 (concurring opinion). His concerns are imaginative,
    but it is questionable whether they are real. Apple juice processors,
    meatcutters, cement manufacturers, and pharmaceutical producers do
    not ordinarily build levees—and it is almost inconceivable that they
    would do so using the waste generated by their highly specific indus
    trial processes. See, e.g., 40 CFR §411.10 (performance standard for
    particular cement manufacturing process). Levee construction gener
    ally is undertaken by developers or government, entities not subject to
    performance standards for such a project. This litigation, furthermore,
    does not illustrate the “difficulty” JUSTICE BREYER perceives. See ante,
    at 1. Coeur Alaska does not seek to build a levee or return dirt to a
    lake; it simply wants to use Lower Slate Lake as a waste disposal site.
    8         COEUR ALASKA, INC. v. SOUTHEAST ALASKA
    CONSERVATION COUNCIL
    GINSBURG, J., dissenting
    manufacturing); id., pt. 425 (leather tanning and finish
    ing); id., pt. 432 (meat and poultry products processing).
    See also Brief for American Rivers et al. as Amici Curiae
    26–27 (observing that discharges in these categories “typi
    cally contain high volumes of solids”). Providing an escape
    hatch for polluters whose discharges contain solid matter,
    it bears noting, is particularly perverse; the Act specifi
    cally focuses on solids as harmful pollutants. See 
    33 U.S. C
    . §1314(a)(4) (requiring EPA to publish information
    regarding “conventional pollutants,” including “suspended
    solids”); Brief for American Rivers, supra, at 28–29, and
    n. 18 (identifying over 50 effluent limitations that restrict
    total suspended solids).5
    Congress, we have recognized, does not “alter the fun
    damental details of a regulatory scheme in vague terms or
    ancillary provisions—it does not, one might say, hide
    elephants in mouseholes.” Whitman v. American Trucking
    Assns., Inc., 
    531 U.S. 457
    , 467–468 (2001). Yet an altera
    tion of that kind is just what today’s decision imagines.
    Congress, as the Court reads the Act, silently upended, in
    an ancillary permitting provision, its painstaking pollu
    tion-control scheme. See ante, at 17. Congress did so, the
    Court holds, notwithstanding the lawmakers’ stated effort
    “to restore and maintain the chemical, physical, and bio
    logical integrity” of the waters of the United States, 33
    ——————
    5 The “safeguards” JUSTICE BREYER identifies are hardly reassuring.
    See ante, at 3 (concurring opinion). Given today’s decision, it is opti
    mistic to expect that EPA or the courts will act vigorously to prevent
    evasion of performance standards. Nor is EPA’s veto power under
    §404(c) of the Clean Water Act an adequate substitute for adherence to
    §306. That power—exercised only a dozen times over 36 years encom
    passing more than one million permit applications, see Brief for Ameri
    can Rivers 14—hinges on a finding of “unacceptable adverse effect,” 
    33 U.S. C
    . §1344(c). Destruction of nearly all aquatic life in a pristine
    lake apparently does not qualify as “unacceptable.” Reliance on ad hoc
    vetoes, moreover, undermines Congress’ aim to install uniform water
    pollution regulation.
    Cite as: 557 U. S. ____ (2009)            9
    GINSBURG, J., dissenting
    U. S. C. §1251(a); their assignment to EPA of the Hercu
    lean task of setting strict effluent limitations for many
    categories of industrial sources; and their insistence that
    new sources meet even more ambitious standards, not
    subject to exception or variance. Would a rational legisla
    ture order exacting pollution limits, yet call all bets off if
    the pollutant, discharged into a lake, will raise the water
    body’s elevation? To say the least, I am persuaded, that
    is not how Congress intended the Clean Water Act to
    operate.
    In sum, it is neither necessary nor proper to read the
    statute as allowing mines to bypass EPA’s zero-discharge
    standard by classifying slurry as “fill material.” The use
    of waters of the United States as “settling ponds” for
    harmful mining waste, the Court of Appeals correctly held,
    is antithetical to the text, structure, and purpose of the
    Clean Water Act.
    *     *    *
    For the reasons stated, I would affirm the judgment of
    the Ninth Circuit.
    

Document Info

Docket Number: 07-984

Citation Numbers: 174 L. Ed. 2d 193, 129 S. Ct. 2458, 557 U.S. 261, 2009 U.S. LEXIS 4730

Judges: Breyer, Ginsburg, Kennedy, Scalia

Filed Date: 6/22/2009

Precedential Status: Precedential

Modified Date: 8/3/2023

Authorities (15)

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Rubie's Costume Company v. United States , 337 F.3d 1350 ( 2003 )

Amer Fed Govt Empl v. Nicholson, R. James , 475 F.3d 341 ( 2007 )

southeast-alaska-conservation-council-sierra-club-lynn-canal-conservation , 486 F.3d 638 ( 2007 )

american-federation-of-government-employees-afl-cio-local-2152-edwin-d , 464 F.3d 1049 ( 2006 )

United States v. Mead Corp. , 121 S. Ct. 2164 ( 2001 )

United States v. Detroit Timber & Lumber Co. , 26 S. Ct. 282 ( 1906 )

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City of Milwaukee v. Illinois , 101 S. Ct. 1784 ( 1981 )

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E. I. Du Pont De Nemours & Co. v. Train , 97 S. Ct. 965 ( 1977 )

Auer v. Robbins , 117 S. Ct. 905 ( 1997 )

Whitman v. American Trucking Assns., Inc. , 121 S. Ct. 903 ( 2001 )

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