Coeur Alaska, Inc. v. Southeast Alaska Conservation Council

OPINION OF THE COURT COEUR ALASKA, INC. V. SOUTHEAST ALASKACONSERVATION COUNCIL 557 U. S. ____ (2009) 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 mining 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 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 discharge 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 (collectively, SEACC). The State of Alaska and Coeur
Alaska are petitioners here.

															   SEACC argues that the permit from the Corps is
unlawful 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.

															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 proposes 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 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 compliance” 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 “material [that] has the effect
of … [c]hanging the bottom elevation” 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 permit 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
consider the environmental consequences of every discharge it
allows. 33 U. S. C. §1344(b). The Corps must apply guidelines
written by the EPA pursuant to §404(b). See ibid.; 40 CFR
pt. 230 (EPA guidelines). Applying those guidelines 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, carbon/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 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 permanently
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
preferable” means of disposing of them. App. 300a. By declining to
exercise its veto, the EPA in effect deferred to the judgment 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 downstream 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 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
restricting 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 aluminum, 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 contended further that the performance
standard is a binding 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
Engineers’ 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 definition 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
promulgating their current and prior definitions of “fill
material.” 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, 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 governing 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
out the provisions of this chapter.” 33 U. S. C. §1342(a)(1)
(emphasis added).

															Section 402 thus forbids the EPA from exercising
permitting 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
function 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 guidelines 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
provide 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 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 inconsistent with the
regulation”; and so we accept it as correct. Auer v. Robbins , 519 U. S. 452 , 461
(1997) (internal quotation 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 permits … 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 Respondent 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 expresses a
concern that Coeur Alaska’s interpretation of the statute will lead
to §404 permits authorizing the discharges 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 guidelines, 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
difficulties for the regulated industry. As the regulatory regime
stands now, a discharger must ask a simple question—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
workable, 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 permit 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 material?

															   We address in turn the statutory
text of the CWA, the agencies’ regulations construing it, and the
EPA’s subsequent interpretation of those regulations. Because
Congress has not “directly spoken” to the “precise question” of
whether an EPA performance standard applies to discharges of fill
material, the statute alone does not resolve the case. Chevron
U. S. A. Inc. v. Natural Resources Defense Council,
Inc. , 467 U. S.
837 , 842 (1984). We look first to the agency regulations, which
are entitled to deference 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
regulatory 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 contrast, 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 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 Effluent 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 regulates
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 EPA’s authority to
regulate these discharges of solid mining 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 application 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 circumstances. 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 discharge, 30% of which
is solid waste.

															2

															   For their part, the State of
Alaska and the federal agencies 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 discharge 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 arguments based on §404’s silence in regard to §306.
First, they note that nothing in §404 requires the Corps to
consider the EPA’s new source performance standard or the §306(e)
prohibition. That silence advances the argument that §404’s grant
of authority to “issue permits” contradicts §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
alleging 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 application 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 permitee would be protected
from a suit seeking a judicial 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
standards 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 performance applicable to
such source”—to mean that a performance standard ceases to be
“applicable” the moment 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 other. The EPA’s new
source performance standard contains 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 similar mining-related materials” in its definition of a
“discharge of fill material,” 40 CFR §232.2; and it contains no
exception for slurry that is regulated by an EPA performance
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
guidelines 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 standards does offer some indication that these
are not relevant 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 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 interpretation and agency application of the regulations are
instructive 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 agencies, 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
responsibility over the mine. App. 141a–149a (Regas Memorandum).
The Memorandum, though not subject to sufficiently formal
procedures to merit Chevron deference, see Mead , supra , at 234–238, is entitled to a measure of deference
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
discharges under section 402, including effluent limitations
guidelines and standards, such as those applicable 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 regulated under section 404
of CWA” “do not require [§402] permits.” The Regas Memorandum takes
an instructive interpretive step when it explains that because the
discharge “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 erroneous 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 regulating the discharge into surrounding waters.
The Memorandum does not purport to invalidate the EPA’s performance
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 smuggles a discharge of
EPA-regulated pollutants into a separate discharge of
Corps-regulated fill material. The instant 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
discharge 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 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,
furthermore, that the alternative—a heap of tailings larger than
the Pentagon placed upon wetlands—would cause more harm to the
environment. Because the Memorandum 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
Memorandum, we find it a sensible and rational construction that
reconciles §§306, 402, and 404, and the regulations implementing
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, however, 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
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
agencies’ 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 possibility 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
conclusion 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 downstream
creek.

															D

															   SEACC argues against deference to
the Regas Memorandum. In its view the Regas Memorandum is contrary
to published agency statements and earlier agency practice. 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 “memorandum 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 Federal Respondents
30–31, n. 8.

															   SEACC points to paragraph B(5) of
the MOA, which reads:

															“[A] pollutant (other than dredged material) will
normally be considered by EPA and the Corps to be subject 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 associated 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 materials.” 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 discharge 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
performance 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’ determination that the Corps regulates all discharges
of fill material 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 “Effluent Guideline Limitations and 402 Permits”:

															“[W]e emphasize that today’s rule generally is
intended to maintain our existing approach to regulating pollutants
under either section 402 or 404 of the CWA. Effluent limitation
guidelines and new source performance standards (‘effluent
guidelines’) promulgated 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 regulate fill material under effluent
guidelines. Rather, effluent guidelines restrict discharges of
pollutants from identified wastestreams based upon the pollutant
reduction capabilities of available treatment technologies.
Recognizing that some discharges (such as suspended or settleable
solids) can have the associated effect, over time, of raising the
bottom elevation of a water due to settling of waterborne
pollutants, we 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 effluent 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 under 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 consistent 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 incorporated
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 considered a discharge of fill
material. Nevertheless, if EPA has previously determined that
certain materials are subject to an [effluent limitation guideline]
under specific circumstances, then that determination remains
valid. Moreover, … permits issued pursuant to section 402
are intended to regulate process water and provide effluent limits
that are protective of receiving water quality. This distinction
provides the framework 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 “remai[n]
valid.” But, as noted above, the Regas Memorandum has followed this
policy by applying the EPA’s performance 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
discharge 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 consistent with this opinion.

															It is so ordered. BREYER, J., CONCURRING COEUR ALASKA, INC. V. SOUTHEAST ALASKACONSERVATION COUNCIL 557 U. S. ____ (2009) 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 those involved in the processing of apples into apple juice or
apple cider, 40 CFR §407.10 (2008); to the manufacturing 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 application of the best available
demonstrated control technology … including, where practicable, a
standard permitting 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) (defining “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 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
discharges 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 reasonable 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
interpretation of the statute as permitting the EPA/Corps of
Engineers “fill” definition to apply to the cases at hand is
reasonable, 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 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 standard
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. 557 U. S. ____ (2009) 557 U. S. ____ (2009) 557 U. S. ____ (2009) 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 protestation, ante , at 20, that it is not
according Chevron deference to the reasonable
interpretation set forth in the memorandum sent by the Director of
the Environmental Protection Agency’s (EPA) Office of Wetlands,
Oceans and Watersheds, to the Director of the EPA’s regional Office
of Water with responsibility over the Coeur Alaska mine—an
interpretation consistently followed by both EPA and the Corps of
Engineers, and adopted by both agencies in the proceedings before
this Court. See Chevron U. S. A. Inc. v. Natural
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 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
inscrutable 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 ambiguous statute but also an ambiguous
regulation. One must conclude, then, that if today’s opinion is not according the agencies’ reasonable and authoritative
interpretation of the Clean Water Act Chevron deference,
it is according 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 without the assurance that reviewing
courts will accept reasonable and authoritative agency
interpretation of ambiguous 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 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.

															 Compare, e.g., Kruse v. Wells
Fargo Home Mortgage, Inc. , 383 F. 3d 49, 61 (CA2 2004)
(according Chevron deference to policy statements issued
by Department of Housing and Urban Development) and Schuetz 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 rulemaking 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). GINSBURG, J., DISSENTING COEUR ALASKA, INC. V. SOUTHEAST ALASKACONSERVATION COUNCIL 557 U. S. ____ (2009) 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
Forest. 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.[ Footnote
1 ]

															   Coeur Alaska’s proposal is prohibited by the
Environmental Protection Agency (EPA) performance standard
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 performance 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 discharges 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 Southeast 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 purpose 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 restore 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
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 Enforcement”—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 provided … , the Administrator of [EPA] shall
administer this [Act].”).

															   The Act instructs EPA to establish various
technology-based, increasingly stringent effluent limitations for
categories of point sources. E.g., §§1311, 1314. These
limitations, 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.[ Footnote 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 standard. 33
U. S. C. §1316(e) (emphasis added). In line with Congress’ aim
“to insure …‘maximum feasible control of new sources,’ ” du Pont , 430 U. S., at 138, the preferred 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.[ Footnote 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 transforms generally applicable
effluent limitations into the individual obligations of each
discharger. EPA v. California 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 permit. 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) eligible 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 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 performance
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 material” 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
administration and receive permits under the NPDES, not §404.

															   This reading accords with the Act’s structure
and objectives. It retains, through the NPDES, uniform application
of the Act’s core pollution-control requirements, and it respects
Congress’ special concern for new sources. Leaving
pollution-related decisions to EPA, moreover, is consistent 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 Congress’ 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 States to identify and restore polluted
lakes).[ Footnote 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 sufficient solid
matter to raise the bottom of a water body, transformed into a
waste disposal facility. Whole categories of regulated industries
can thereby gain immunity from a variety of pollution-control
standards. The loophole would swallow not only standards governing
mining activities, see 40 CFR pt. 440 (effluent limitations and new
source performance standards for ore mining and dressing); id. , pt. 434 (coal mining); id. , pt. 436 (mineral
mining), but also standards for dozens of other categories of
regulated point sources, see, e.g., id. , pt. 411
(cement manufacturing); id. , pt. 425 (leather tanning and
finishing); 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 “typically contain high volumes of solids”). Providing
an escape hatch for polluters whose discharges contain solid
matter, it bears noting, is particularly perverse; the Act
specifically 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).[ Footnote
5 ]

															   Congress, we have recognized, does not “alter
the fundamental 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 alteration 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 pollution-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
biological integrity” of the waters of the United States, 33 U.
S. C. §1251(a); their assignment to EPA of the Herculean 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 legislature 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. Footnote 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). Footnote 2 In addition, the Act requires States to
institute comprehensive water 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). Footnote 3 Even the provision allowing the President to
exempt federal installations 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). Footnote 4 The Court asserts that “numerous
difficulties” will ensue if a discharge 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 industrial
processes. See, e.g., 40 CFR §411.10 (performance standard
for particular cement manufacturing process). Levee
construction generally 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. Footnote
5 The “safeguards”
Justice Breyer identifies are hardly reassuring. See ante ,
at 3 (concurring opinion). Given today’s decision, it is optimistic
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
encompassing more than one million permit applications, see Brief
for American 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.

Summary: The Supreme Court ruled that the US Army Corps of Engineers had the authority to issue a permit to Coeur Alaska for discharging mining waste into a lake, under the Clean Water Act. The Court also decided that the permit was lawful, despite opposition from environmental groups who argued that it violated an EPA regulation. The Court's decision considered the potential impact on water quality and the precedent for similar cases.