OPINION OF THE COURT ENVIRONMENTAL DEFENSE V. DUKE ENERGY CORP. 549 U. S. ____ (2007) SUPREME COURT OF THE UNITED STATES NO. 05-848 ENVIRONMENTAL DEFENSE, et al., PETITIONERS v. DUKE ENERGY CORPORATION et al.

															on writ of certiorari to the united states court of
appeals for the fourth circuit

															[April 2, 2007]

															   Justice Souter delivered the
opinion of the Court.

															   In the 1970s, Congress added two
air pollution control schemes to the Clean Air Act: New Source
Performance Standards (NSPS) and Prevention of Significant
Deterioration (PSD), each of them covering modified, as well as
new, stationary sources of air pollution. The NSPS provisions
define the term “modification,” 42 U. S. C. §7411(a)(4), while
the PSD provisions use that word “as defined in” NSPS, §7479(2)(C).
The Court of Appeals concluded that the statute requires the
Environmental Protection Agency (EPA) to conform its PSD
regulations on “modification” to their NSPS counterparts, and that
EPA’s 1980 PSD regulations can be given this conforming
construction. We hold that the Court of Appeals’s reading of the
1980 PSD regulations, intended to align them with NSPS, was
inconsistent with their terms and effectively invalidated them; any
such result must be shown to comport with the Act’s restrictions on
judicial review of EPA regulations for validity.

															I

															   The Clean Air Amendments of 1970,
84 Stat. 1676, broadened federal authority to combat air pollution,
see Chevron U. S. A. Inc. v. Natural Resources
Defense Council, Inc. , 467 U. S. 837 , 845–846
(1984), and directed EPA to devise National Ambient Air Quality
Standards (NAAQS) limiting various pollutants, which the States
were obliged to implement and enforce, 42 U. S. C. §§7409,
7410. The amendments dealing with NSPS authorized EPA to require
operators of stationary sources of air pollutants to use the best
technology for limiting pollution, Chevron , supra, at 846; see also 1 F. Grad, Environmental Law
§2.03, p. 2–356 (2006), both in newly constructed sources and
those undergoing “modification,” 42 U. S. C. §7411(a)(2).
Section 111(a) of the 1970 amendments defined this term within the
NSPS scheme as “any physical change in, or change in the method of
operation of, a stationary source which increases the amount of any
air pollutant emitted by such source or which results in the
emission of any air pollutant not previously emitted,” 42 U.
S. C. §7411(a)(4).

															   EPA’s 1975 regulations
implementing NSPS provided generally that “any physical or
operational change to an existing facility which results in an
increase in the emission rate to the atmosphere of any pollutant to
which a standard applies shall be considered a modification within
the meaning of [S]ection 111.” 40 CFR §60.14(a) (1976). Especially
significant here is the identification of an NSPS “modification” as
a change that “increase[s] … the emission rate,” which “shall be
expressed as kg/hr of any pollutant discharged into the
atmosphere.” §60.14(b).[ Footnote
1 ]

															   NSPS, however, did too little to “achiev[e]
the ambitious goals of the 1970 Amendments,” R. Belden, Clean Air
Act 7 (2001) (hereinafter Belden), and the Clean Air Act Amendments
of 1977, 91 Stat. 685, included the PSD provisions, which aimed at
giving added protection to air quality in certain parts of the
country “notwithstanding attainment and maintenance of” the NAAQS.
42 U. S. C. §7470(1).[ Footnote
2 ] The 1977 amendments required a PSD permit before a “major
emitting facility” could be “constructed” in an area covered by the
scheme. §7475(a). As originally enacted, PSD applied only to newly
constructed sources, but soon a technical amendment added the
following subparagraph: “The term ‘construction’ when used in
connection with any source or facility, includes the modification
(as defined in [S]ection 111(a)) of any source or facility.”
§14(a)(54), 91 Stat. 1402, 42 U. S. C. §7479(2)(C); see also New York v. EPA , 413 F. 3d 3, 13 (CADC
2005). In other words, the “construction” requiring a PSD permit
under the statute was made to include (though it was not limited
to) a “modification” as defined in the statutory NSPS
provisions.

															   In 1980, EPA issued PSD regulations,[ Footnote 3 ] which “limited the
application of [PSD] review” of modified sources to instances of
“ ‘major’ modificatio[n],” Belden 46, defined as “any physical
change in or change in the method of operation of a major
stationary source that would result in a significant net emissions
increase of any pollutant subject to regulation under the Act.” 40
CFR §51.166(b)(2)(i) (1987). Further regulations in turn addressed
various elements of this definition, three of which are to the
point here. First, the regulations specified that an operational
change consisting merely of “[a]n increase in the hours of
operation or in the production rate” would not generally constitute
a “physical change or change in the method of operation.”
§51.166(b)(2)(iii)( f ). For purposes of a PSD permit,
that is, such an operational change would not amount to a
“modification” as the Act defines it. Second, the PSD regulations
defined a “net emissions increase” as “[a]ny increase in actual
emissions from a particular physical change or change in the method
of operation,” net of other contemporaneous “increases and
decreases in actual emissions at the source.” §51.166(b)(3).
“Actual emissions” were defined to “equal the average rate, in tons
per year, at which the unit actually emitted the pollutant during a
two-year period which precedes the particular date and which is
representative of normal source operation.” §51.166(b)(21)(ii).
“[A]ctual emissions” were to be “calculated using the unit’s actual
operating hours [and] production rates.” Ibid. Third, the
term “significant” was defined as “a rate of emissions that would
equal or exceed” one or another enumerated threshold, each
expressed in “tons per year.” §51.166(b)(23)(i).

															   It would be bold to try to synthesize these
statutory and regulatory provisions in a concise paragraph, but
three points are relatively clear about the regime that covers this
case:

															(a)   The Act defines modification
of a stationary source of a pollutant as a physical change to it,
or a change in the method of its operation, that increases the
amount of a pollutant discharged or emits a new one.

															(b)   EPA’s NSPS regulations require a source to
use the best available pollution-limiting technology only when a
modification would increase the rate of discharge of pollutants
measured in kilograms per hour.

															(c)   EPA’s 1980 PSD regulations require a permit
for a modification (with the same statutory definition) only when
it is a major one and only when it would increase the actual annual
emission of a pollutant above the actual average for the two prior
years.

															   The Court of Appeals held that
Congress’s provision defining a PSD modification by reference to an
NSPS modification caught not only the statutory NSPS definition,
but also whatever regulatory gloss EPA puts on that definition at
any given time (for the purposes of the best technology
requirement). When, therefore, EPA’s PSD regulations specify the
“change” that amounts to a “major modification” requiring a PSD
permit, they must measure an increase in “the amount of any air
pollutant emitted,” 42 U. S. C. §7411(a)(4), in terms of the
hourly rate of discharge, just the way NSPS regulations do.
Petitioners and the United States say, on the contrary, that when
EPA addresses the object of the PSD scheme it is free to put a
different regulatory interpretation on the common statutory core of
“modification,” by measuring increased emission not in terms of
hourly rate but by the actual, annual discharge of a pollutant that
will follow the modification, regardless of rate per hour. This
disagreement is the nub of the case.

															II

															   Respondent Duke Energy
Corporation runs 30 coal-fired electric generating units at eight
plants in North and South Carolina. United States v. Duke Energy Corp. , 411 F. 3d 539, 544 (CA4 2005). The
units were placed in service between 1940 and 1975, and each
includes a boiler containing thousands of steel tubes arranged in
sets. Ibid. Between 1988 and 2000,[ Footnote 4 ] Duke replaced or redesigned 29 tube
assemblies in order to extend the life of the units and allow them
to run longer each day. Ibid. The United States filed this
action in 2000, claiming, among other things, that Duke
violated the PSD provisions by doing this work without permits.
Environmental Defense, North Carolina Sierra Club, and North
Carolina Public Interest Research Group Citizen Lobby/Education
Fund intervened as plaintiffs and filed a complaint charging
similar violations.

															   Duke moved for summary judgment, one of its
positions being that none of the projects was a “major
modification” requiring a PSD permit because none increased hourly
rates of emissions. The District Court agreed with Duke’s reading
of the 1980 PSD regulations. It reasoned that their express
exclusion of “[a]n increase in the hours of operation” from the
definition of a “physical change or change in the method of
operation” implied that “post-project emissions levels must be
calculated assuming” preproject hours of operation. 278
F. Supp. 2d 619, 640–641 (MDNC 2003). Consequently, the
District Court said, a PSD “major modification” can occur “only if
the project increases the hourly rate of emissions.” Id .,
at 641. The District Court found further support for its
construction of the 1980 PSD regulations in one letter and one
memorandum written in 1981 by EPA’s Director of the Division of
Stationary Source Enforcement, Edward E. Reich. Id., at
641–642.

															   The United States and intervenor-plaintiffs
(collectively, plaintiffs) subsequently stipulated “that they do
not contend that the projects at issue in this case caused an
increase in the maximum hourly rate of emissions at any of Duke
Energy’s units.” App. 504. Rather, their claim “is based solely on
their contention that the projects would have been projected to
result in an increased utilization of the units at issue.” Ibid . Duke, for its part, stipulated to plaintiffs’ right
to appeal the District Court’s determination that projects
resulting in greater operating hours are not “major modifications”
triggering the PSD permit requirement, absent an increase in the
hourly rate of emissions. The District Court then entered summary
judgment for Duke on all PSD claims.

															   The Court of Appeals for the Fourth Circuit
affirmed, “albeit for somewhat different reasons.” 411 F. 3d,
at 542. “[T]he language and various interpretations of the PSD
regulations … are largely irrelevant to the proper analysis of this
case,” reasoned the Court of Appeals, “because Congress’ decision
to create identical statutory definitions of the term
‘modification’ ” in the NSPS and PSD provisions of the Clean
Air Act “has affirmatively mandated that this term be interpreted
identically” in the regulations promulgated under those provisions. Id., at 547, n. 3, 550. The Court of Appeals relied
principally on the authority of Rowan Cos. v. United
States , 452 U.
S. 247 , 250 (1981), where we held against the Government’s
differing interpretations of the word “wages” in different tax
provisions. 411 F. 3d, at 550. As the Court of Appeals saw it, Rowan establishes an “effectively irrebuttable”
presumption that PSD regulations must contain the same conditions
for a “modification” as the NSPS regulations, including an increase
in the hourly rate of emissions.[ Footnote 5 ] 411 F. 3d, at 550.

															   As the Court of Appeals said, Duke had not
initially relied on Rowan , see 411 F. 3d, at 547,
n. 4, and when the Court sU. S.onte requested
supplemental briefing on Rowan ’s relevance, plaintiffs
injected a new issue into the case. They argued that a claim that
the 1980 PSD regulation exceeded statutory authority would be an
attack on the validity of the regulation that could not be raised
in an enforcement proceeding. See 42 U. S. C. §7607(b)(2).
Under §307(b) of the Act, they said, judicial review for validity
can be obtained only by a petition to the Court of Appeals for the
District of Columbia Circuit, generally within 60 days of EPA’s
rulemaking. 42 U. S. C. §7607(b).

															   The Court of Appeals rejected this argument.
“Our choice of this interpretation of the PSD regulations … is not
an invalidation of those regulations,” it said, because “the PSD
regulations can be interpreted” to require an increase in the
hourly emissions rate as an element of a major “modification”
triggering the permit requirement. 411 F. 3d, at 549,
n. 7. To show that the 1980 PSD regulations are open to this
construction, the Court of Appeals cited the conclusions of the
District Court and the Reich opinions.

															   We granted the petition for certiorari brought
by intervenor-plaintiffs, 547 U. S. __ (2006), and now vacate.

															III

															   The Court of Appeals understood
that it was simply construing EPA’s 1980 PSD regulations in a
permissible way that left them in harmony with their NSPS
counterpart and, hence, the Act’s single definition of
“modification.” The plaintiffs say that the Court of Appeals was
rewriting the PSD regulations in a way neither required by the Act
nor consistent with their own text.

															   It is true that no precise line
runs between a purposeful but permissible reading of the regulation
adopted to bring it into harmony with the Court of Appeals’s view
of the statute, and a determination that the regulation as written
is invalid. But the latter occurred here, for the Court of
Appeals’s efforts to trim the PSD regulations to match their
different NSPS counterparts can only be seen as an implicit
declaration that the PSD regulations were invalid as written.

															A

															   In applying the 1980 PSD
regulations to Duke’s conduct, the Court of Appeals thought that,
by defining the term “modification” identically in its NSPS and PSD
provisions, the Act required EPA to conform its PSD interpretation
of that definition to any such interpretation it reasonably adhered
to under NSPS. But principles of statutory construction are not so
rigid. Although we presume that the same term has the same meaning
when it occurs here and there in a single statute, the Court of
Appeals mischaracterized that presumption as “effectively
irrebuttable.” 411 F. 3d, at 550. We also understand that
“[m]ost words have different shades of meaning and consequently may
be variously construed, not only when they occur in different
statutes, but when used more than once in the same statute or even
in the same section.” Atlantic Cleaners & Dyers, Inc. v. United States , 286 U. S. 427 , 433
(1932). Thus, the “natural presumption that identical words used in
different parts of the same act are intended to have the same
meaning … is not rigid and readily yields whenever there is such
variation in the connection in which the words are used as
reasonably to warrant the conclusion that they were employed in
different parts of the act with different intent.” Ibid. A
given term in the same statute may take on distinct characters from
association with distinct statutory objects calling for different
implementation strategies.

															   The point is the same even when
the terms share a common statutory definition, if it is general
enough, as we recognized in Robinson v. Shell Oil
Co. , 519 U. S.
337 (1997). There the question was whether the term “employees”
in §704(a) of Title VII of the Civil Rights Act of 1964 covered
former employees. Title VII expressly defined the term “employee,”
42 U. S. C. §2000e(f), but the definition was “consistent with
either current or past employment,” 519 U. S., at 342, and we held
that “each section” of Title VII “must be analyzed to determine
whether the context gives the term a further meaning that would
resolve the issue in dispute,” id., at 343–344.

															   If Robinson were inconsistent with Rowan (on which the Court of Appeals relied), it would be
significant that Robinson is the later case, but we read
the two as compatible. In Rowan , the question was whether
the value of meals and lodging given to employees by an employer
for its own convenience should be counted in computing “wages”
under the Federal Insurance Contributions Act (FICA), 26 U.
S. C. §3101 et seq ., and the Federal Unemployment Tax
Act (FUTA), 26 U. S. C. §3301 et seq . Treasury
Regulations made this value “includable in ‘wages’ as defined in
FICA and FUTA, even though excludable from ‘wages’ under the
substantially identical” statutory definition of “wages” for
income-tax withholding purposes. 452 U. S., at 252. Although we
ultimately held that the income tax treatment was the proper one
across the board, we did not see it this way simply because a
“substantially identical” definition of “wages” appeared in each of
the different statutory provisions. Instead, we relied on a
manifest “congressional concern for the interest of simplicity and
ease of administration.” Id., at 255 (internal quotation
marks omitted). The FICA and FUTA regulations fell for failing to
“serve that interest,” id., at 257, not for defying
definitional identity.

															   In fact, in a setting much like Rowan , we recently declined to require uniformity when
resolving ambiguities in identical statutory terms. In United
States v. Cleveland Indians Baseball Co. , 532 U. S. 200 (2001), we
rejected the notion that using the phrase “wages paid” in both “the
discrete taxation and benefits eligibility contexts” can, standing
alone, “compel symmetrical construction,” id., at 213; we
gave “substantial judicial deference” to the “longstanding,”
“reasonable,” and differing interpretations adopted by the Internal
Revenue Service in its regulations and Revenue Rulings. Id., at 218–220. There is, then, no “effectively
irrebuttable” presumption that the same defined term in different
provisions of the same statute must “be interpreted identically.”
411 F. 3d, at 550. Context counts.

															   It is true that the Clean Air Act did not
merely repeat the term “modification” or the same definition of
that word in its NSPS and PSD sections; the PSD language referred
back to the section defining “modification” for NSPS purposes. 42
U. S. C. §7479(2)(C). But that did not matter in Robinson, and we do not see the distinction as making any
difference here. Nothing in the text or the legislative history of
the technical amendments that added the cross-reference to NSPS
suggests that Congress had details of regulatory implementation in
mind when it imposed PSD requirements on modified sources; the
cross-reference alone is certainly no unambiguous congressional
code for eliminating the customary agency discretion to resolve
questions about a statutory definition by looking to the
surroundings of the defined term, where it occurs. See New
York, 413 F. 3d, at 19 (“So far as appears, … [this]
incorporatio[n] by reference [is] the equivalent of Congress’s
having simply repeated in the [PSD] context the definitional
language used before in the NSPS context”); compare 91 Stat. 745
(expressly incorporating in an unrelated provision of the 1977
amendments “the interpretative regulation of the [EPA]
Administrator … published in 41 Federal Register 55524–30” with
specified exceptions); New York, supra, at 19 (“Congress’s
failure to use such an express incorporation of prior regulations
for ‘modification’ cuts against” any suggestion that “Congress
intended to incorporate” into the Act the “preexisting regulatory
definition” of “modification”). Absent any iron rule to ignore the
reasons for regulating PSD and NSPS “modifications” differently,
EPA’s construction need do no more than fall within the limits of
what is reasonable, as set by the Act’s common[ Footnote 6 ] definition.

															B

															   The Court of Appeals’s reasoning
that the PSD regulations must conform to their NSPS counterparts
led the court to read those PSD regulations in a way that seems to
us too far a stretch for the language used. The 1980 PSD
regulations on “modification” simply cannot be taken to track the
agency’s regulatory definition under the NSPS.

															   True, the 1980 PSD regulations
may be no seamless narrative, but they clearly do not define a
“major modification” in terms of an increase in the “hourly
emissions rate.” On its face, the definition in the PSD regulations
specifies no rate at all, hourly or annual, merely requiring a
physical or operational change “that would result in a significant
net emissions increase of any” regulated pollutant. 40 CFR
§51.166(b)(2)(i). But even when a rate is mentioned, as in the
regulatory definitions of the two terms, “significant” and “net
emissions increase,” the rate is annual, not hourly. Each of the
thresholds that quantify “significant” is described in “tons per
year,” §51.166(b)(23)(i), and a “net emissions increase” is an
“increase in actual emissions” measured against an “average” prior
emissions rate of so many “tons per year.” §§51.166(b)(3) and
(21)(ii). And what is further at odds with the idea that hourly
rate is relevant is the mandate that “[a]ctual emissions shall be
calculated using the unit’s actual operating hours,”
§51.166(b)(21)(ii) , since “actual emissions” must be
measured in a manner that looks to the number of hours the unit is
or probably will be actually running. What these provisions are
getting at is a measure of actual operations averaged over time,
and the regulatory language simply cannot be squared with a regime
under which “hourly rate of emissions,” 411 F. 3d, at 550
(emphasis deleted), is dispositive.

															   The reasons invoked by the Court of Appeals
for its different view are no match for these textual differences.
The appellate court cited two authorities ostensibly demonstrating
that the 1980 PSD regulations “can be interpreted consistently”
with the hourly emissions test, the first being the analysis of the
District Court in this case. Id . , at 549, n. 7.
The District Court thought that an increase in the hourly emissions
rate was necessarily a prerequisite to a PSD “major modification”
because a provision of the 1980 PSD regulations excluded an
“ ‘increase in the hours of operation or in the production
rate’ ” from the scope of “ ‘[a] physical change or
change in the method of operation.’ ” 278 F. Supp. 2d, at
640–641 (quoting 40 CFR §§51.166(b)(2)(iii)( f ) and
(3)(i)( a ) (1987)). The District Court read this exclusion
to require, in effect, that a source’s hours of operation “be held
constant” when preproject emissions are being compared with
postproject emissions for the purpose of calculating the “net
emissions increase.” 278 F. Supp. 2d, at 640.

															   We think this understanding of the 1980 PSD
regulations makes the mistake of overlooking the difference between
the two separate components of the regulatory definition of “major
modification”: “[1] any physical change in or change in the method
of operation of a major stationary source that [2] would result in
a significant net emissions increase of any pollutant subject to
regulation under the Act.” §51.166(b)(2)(i); cf. New York, 413 F. 3d, at 11 (“[The statutory] definition requires both a change—whether physical or operational— and a resulting increase in emissions of a pollutant” (emphasis in
original)); Wisconsin Electric Power Co. v. Reilly , 893 F. 2d 901, 907 (CA7 1990) (same). The
exclusion of “increase in … hours … or … production rate,”
§51.166(b)(2)(iii)( f ), speaks to the first of these
components (“physical change … or change in … method,”
§51.166(b)(2)(i)), but not to the second (“significant net
emissions increase,” ibid .). As the preamble to the 1980
PSD regulations explains, forcing companies to obtain a PSD permit
before they could simply adjust operating hours “would severely and
unduly hamper the ability of any company to take advantage of
favorable market conditions.” 45 Fed. Reg. 52704. In other words, a
mere increase in the hours of operation, standing alone, is not a
“physical change or change in the method of operation.” 40 CFR
§51.166(b)(2)(iii).

															   But the District Court took this language a
step further. It assumed that increases in operating hours
(resulting in emissions increases at the old rate per hour) must be
ignored even if caused or enabled by an independent “physical
change … or change in the method of operation.” §51.166(b)(2)(i).
That reading, however, turns an exception to the first component of
the definition into a mandate to ignore the very facts that would
count under the second, which defines “net emissions increase” in
terms of “actual emissions,” §51.166(b)(3), during “the unit’s
actual operating hours,” §51.166(b)(21)(ii); see also 57 Fed. Reg.
32328 (1992) (“[A]n increase in emissions attributable to an
increase in hours of operation or production rate which is the
result of a construction-related activity is not excluded from
[PSD] review …”).[ Footnote
7 ]

															   The Court of Appeals invoked one other source
of support, the suggestion in the Reich opinions that a physical or
operational change increasing a source’s hours of operation,
without an increase in the hourly emissions rate, cannot be a PSD
“major modification.” Duke continues to rely on those opinions
here, asserting that “there are no contrary Agency pronouncements.”
Brief for Respondent Duke 28. The Reich letters are not, however,
heavy ammunition. Their persuasiveness is elusive, neither of them
containing more than one brief and conclusory statement supporting
Duke’s position. Nor, it seems, are they unembarrassed by any
“contrary Agency pronouncements.” See, e.g. , App. 258
(Memorandum of Don R. Clay, Acting Assistant EPA Administrator for
Air and Radiation (Sept. 9, 1988) (when “plans to increase
production rate or hours of operation are inextricably intertwined
with the physical changes planned,” they are “precisely the type of
change in hours or rate o[f] operation that would disturb a prior
assessment of a source’s environmental impact and should have to
undergo PSD review scrutiny” (internal quotation marks and
alterations omitted)); see also 57 Fed. Reg. 32328. In any event,
it answers the citation of the Reich letters to realize that an
isolated opinion of an agency official does not authorize a court
to read a regulation inconsistently with its language.[ Footnote 8 ]

															   In sum, the text of the 1980 PSD regulations
on “modification” doomed the Court of Appeals’s attempt to equate
those regulations with their NSPS counterpart. As a consequence, we
have to see the Court of Appeals’s construction of the 1980 PSD
regulations as an implicit invalidation of those regulations, a
form of judicial review implicating the provisions of §307(b) of
the Act, which limit challenges to the validity of a regulation
during enforcement proceedings when such review “could have been
obtained” in the Court of Appeals for the District of Columbia
within 60 days of EPA rulemaking. See 42 U. S. C. §7607(b);
see also United States v. Cinergy Corp., 458
F. 3d 705, 707–708 (CA7 2006); Wisconsin Electric Power
Co., 893 F. 2d, at 914, n. 6. Because the Court of
Appeals did not believe that its analysis reached validity, it did
not consider the applicability or effect of that limitation here.
We have no occasion at this point to consider the significance of
§307(b) ourselves.

															IV

															   Finally, Duke assumes for
argument that the Act and the 1980 regulations may authorize EPA to
construe a PSD “modification” as it has done, but it charges that
the agency has taken inconsistent positions and is now
“retroactively targeting twenty years of accepted practice.” Brief
for Respondent Duke 37; see also Brief for State of Alabama
et al. as Amici Curiae . This claim, too, has not been
tackled by the District Court or the Court of Appeals; to the
extent it is not procedurally foreclosed, Duke may press it on
remand.

															*  *  *

															   The judgment of the Court of
Appeals is vacated, and the case is remanded for further
proceedings consistent with this opinion.

															It is so ordered. Footnote 1 EPA’s 1975 NSPS regulations did not specify
that the “rate” means the maximum rate possible for the technology,
see 40 CFR §§60.14(a)–(b) (1977), but the parties all read the
regulations this way. See Brief for Petitioners 2; Brief for United
States 7; Brief for Respondent Duke 32. At another point in the
NSPS regulations, a different definition of “modification”
appeared: “ ‘Modification’ means any physical change in, or
change in the method of operation of, an existing facility which
increases the amount of any air pollutant (to which a standard
applies) emitted into the atmosphere by that facility,” §60.2(h);
see also New York v. EPA , 413 F. 3d 3, 11–12
(CADC 2005) (per curiam) (“[N]either the 1975 regulation
nor its preamble explained why EPA found it necessary to offer
these two separate glosses on ‘modification’ ”). Footnote 2 Statutory PSD superseded a regulatory PSD
scheme established by EPA in 1974. See 39 Fed. Reg. 42510. Under
the regulations, the term “modification” was defined as “any
physical change in, or change in the method of operation of, a
stationary source which increases the emission rate of any
pollutant for which a national standard has been promulgated.” Id ., at 42514. Footnote 3 Although EPA had promulgated an earlier set
of PSD regulations in 1978, 43 Fed. Reg. 26380, none of the parties
argues that they govern the conduct at issue in this case. Footnote 4 The United States argues that some of Duke’s
projects were governed by EPA’s PSD regulations promulgated in 1992
rather than the 1980 PSD regulations. Brief for United States 20,
n. 4. Duke disputes this. Brief for Respondent Duke 14, n. 4.
Because the United States acknowledges that the two sets of
regulations “did not materially differ with respect to the legal
question at issue here,” Brief for United States 20, n. 4, we will
assume, as did the Court of Appeals and the District Court, that
the 1980 PSD regulations control. 411 F. 3d, at 543,
n. 1; United States v. Duke Energy Corp .,
278 F. Supp. 2d 619, 629 (MDNC 2003). Footnote 5 The Court of Appeals noted that EPA was free
to abandon the requirement that a “modification” be accompanied by
an increase in the hourly rate of emissions, provided it did so for
both the NSPS and PSD programs. 411 F. 3d, at 550–551. In
other words, the Court of Appeals raised no question about the
reasonableness of the definition of “modification” in the 1980 PSD
regulations, apart from its deviation from the definition contained
in NSPS regulations. Footnote 6 Duke argues that the 1977 amendments intended
to incorporate EPA’s definition of “modification” under the 1974
regulatory PSD program. Brief for Respondent Duke 44; see also
n. 2, supra . We find no support for this argument in
the statutory text, which refers to the statutory NSPS definition
rather than the regulatory PSD definition. Although Duke correctly
points out that “Congress instructed that the bulk of the
pre-existing rules ‘shall remain in effect,’ ” Brief for
Respondent Duke 44 (quoting 42 U. S. C. §7478(a)), this
instruction was a temporary measure “[u]ntil such time as an
applicable implementation plan is in effect,” §7478(a). We
therefore do not read this language as a restriction on EPA’s
authority to interpret the statutory PSD provisions reasonably in a
manner that departs from the 1974 regulations. Duke also invokes Bragdon v. Abbott , 524 U. S. 624 , 631
(1998), for the proposition that “use of the pre-existing term
‘modification’ ‘carries the implication that Congress intended the
term to be construed in accordance with pre-existing regulatory
interpretations.’ ” Brief for Respondent Duke 44. But this
reasoning is unavailing here, given the existence of at least three
distinct regulatory definitions of “modification” at the time of
the 1977 amendments. See supra , at 2–3, and nn. 1, 2. Footnote 7 Two Courts of Appeals agree. See United
States v. Cinergy Corp ., 458 F. 3d 705, 708 (CA7
2006) (“[M]erely running the plant closer to its maximum capacity
is not a major modification because it does not involve either a
physical change or a change in the method of operation.
If, however, a physical change enables the plant to increase its
output, then, according to the EPA’s interpretation, the exclusion
for merely operating the plant for longer hours is inapplicable”
(emphasis in original)); Wisconsin Electric Power Co . v. Reilly , 893 F. 2d 901, 916, n. 11 (CA7 1990)
(the regulatory exclusion for increases in the hours
of operation “was provided to allow facilities to take
advantage of fluctuating market conditions, not construction or
modification activity”); Puerto Rican Cement Co . v. EPA , 889 F. 2d 292, 298 (CA1 1989) (“[T]here is no
logical contradiction in rules that, on the one hand, permit firms
using existing capacity simply to increase their output
and, on the other, use the potential output of new capacity as a basis for calculating an increase in emissions
levels” (emphasis in original)). Footnote 8 Duke now offers an alternative argument for
applying the hourly emissions test for the PSD program: before a
project can become a “major modification” under the PSD
regulations, 40 CFR §51.166(b)(2)(i) (1987), it must meet the
definition of “modification” under the NSPS regulations, §60.14(a).
That sounds right, but the language of the regulations does not
support it. For example, it would be superfluous for PSD
regulations to require a “major modification” to be “a physical
change in or change in the method of operation,” §51.166(b)(2)(i),
if they presupposed that the NSPS definition of “modification,”
which contains the same prerequisite, §60.14(a), had already been
satisfied. The NSPS and PSD regulations are complementary and not
related as set to subset. THOMAS, J., CONCURRING IN PART ENVIRONMENTAL DEFENSE V. DUKE ENERGY CORP. 549 U. S. ____ (2007) SUPREME COURT OF THE UNITED STATES NO. 05-848 ENVIRONMENTAL DEFENSE, et al., PETITIONERS v. DUKE ENERGY CORPORATION et al.

															on writ of certiorari to the united states court of
appeals for the fourth circuit

															[April 2, 2007]

															   Justice Thomas, concurring in
part.

															   I join all but Part III–A of the
Court’s opinion. I write separately to note my disagreement with
the dicta in that portion of the opinion, which states that the
statutory cross-reference does not mandate a singular regulatory
construction.

															   The Prevention of Significant Deterioration
(PSD) statute explicitly links the definition of the term
“modification” to that term’s definition in the New Source
Performance Standard (NSPS) statute:

															“The term ‘construction’ when used in connection
with any source or facility, includes the modification (as defined
in section 7411(a) of this title) of any source or facility.” 42 U.
S. C. §7479(2)(C).

															Section 7411(a) contains the NSPS definition of
“modification,” which the parties agree is the relevant statutory
definition of the term for both PSD and NSPS. Because of the
cross-reference, the definitions of “modification” in PSD and NSPS
are one and the same. The term “modification” therefore has the
same meaning despite contextual variations in the two admittedly
different statutory schemes. Congress’ explicit linkage of PSD’s
definition of “modification” to NSPS’ prevents the Environmental
Protection Agency (EPA) from adopting differing regulatory
definitions of “modification” for PSD and NSPS. Cf. IBP,
Inc. v. Alvarez , 546 U. S. 21 , 34 (2005)
(concluding that an “explicit reference” to a previous statutory
definition prohibits interpreting the same word differently).

															   Section 7479(2)(C)’s cross-reference carries
more meaning than the mere repetition of the same word in a
different statutory context. When Congress repeats the same word in
a different statutory context, it is possible that Congress might
have intended the context to alter the meaning of the word. See Atlantic Cleaners & Dyers, Inc. v. United
States , 286 U.
S. 427 , 433 (1932). No such possibility exists with
§7479(2)(C). By incorporating NSPS’ definition of “modification,”
Congress demonstrated that it did not intend for PSD’s definition
of “modification” to hinge on contextual factors unique to the PSD
statutory scheme. Thus, United States v. Cleveland
Indians Baseball Co. , 532 U. S. 200 (2001),
which analyzes the mere repetition of the same word in a different
statutory context, carries little weight in this situation.

															   Likewise, this case differs from the
circumstance we faced in Robinson v. Shell Oil
Co. , 519 U. S.
337 (1997). In Robinson , we considered whether
“employee,” as used in §704(a) of Title VII of the Civil Rights Act
of 1964, included former employees. We determined that under the
clear language of the statute, certain statutory provisions using
the term “employee” made sense only with respect to former
employees or current employees, but not both. Id. , at
342–343. Accordingly, upon analyzing the context of §704(a), we
were compelled to conclude that the term “employee” included former
employees. This case does not present a similar situation. The
statute here includes a statutory cross-reference, which conveys a
clear congressional intent to provide a common definition for the
term “modification.” And the contextual differences between PSD and
NSPS do not compel different meanings for the term “modification.” Robinson is, therefore, inapplicable.

															   Even if the cross-reference were merely the
equivalent of repeating the words of the definition, we must still
apply our usual presumption that the same words repeated in
different parts of the same statute have the same meaning. See Atlantic Cleaners , supra , at 433; ante ,
at 9. That presumption has not been overcome here. While the
broadly stated regulatory goals of PSD and NSPS differ, these
contextual differences do not compel different definitions of
“modification.” That is, unlike in Robinson , reading the
statutory definition in the separate contexts of PSD and NSPS does
not require different interpretations of the term “modification.”
EPA demonstrated as much when it recently proposed regulations that
would unify the regulatory definitions of “modification.” See 70
Fed. Reg. 61083, n. 3 (2005) (terming the proposal “an appropriate
exercise of our discretion” and stating that the unified definition
better serves PSD’s goals).

															   The majority opinion does little to overcome
the presumption that the same words, when repeated, carry the same
meaning. Instead, it explains that this Court’s cases do not compel
identical language to be interpreted identically in all situations.
Granting that point, the majority still has the burden of stating
why our general presumption does not control the outcome here. It
has not done so.

Summary: In *Environmental Defense v. Duke Energy Corp.* (2007), the Supreme Court considered the definition of the term "modification" in the Clean Air Act's New Source Performance Standards (NSPS) and Prevention of Significant Deterioration (PSD) provisions. The Court held that the term "modification" should be interpreted consistently across both provisions and that the Environmental Protection Agency's (EPA) regulations must align with this interpretation. The case centered on the statutory cross-reference in the PSD provisions, which adopted the NSPS definition of "modification," indicating a clear intent for a shared definition. While the regulatory goals of PSD and NSPS differ, the Court found that these contextual differences do not necessitate distinct definitions of "modification."


OPINION OF THE COURT UNITED STATES V. ATLANTIC RESEARCH CORP. 551 U. S. ____ (2007) SUPREME COURT OF THE UNITED STATES NO. 06-562 UNITED STATES, PETITIONER v. ATLANTIC
RESEARCH CORPORATION

															on writ of certiorari to the united states court of
appeals for the eighth circuit

															[June 11, 2007]

															   Justice Thomas delivered the
opinion of the Court.

															   Two provisions of the
Comprehensive Environmental Response, Compensation, and Liability
Act of 1980 (CERCLA)—§§107(a) and 113(f)—allow private parties to
recover expenses associated with cleaning up contaminated sites. 42
U. S. C. §§9607(a), 9613(f). In this case, we must decide a
question left open in Cooper Industries, Inc. v. Aviall Services, Inc. , 543 U. S. 157 , 161 (2004): whether
§107(a) provides so-called potentially responsible parties (PRPs),
42 U. S. C. §§9607(a)(1)–(4), with a cause of action to
recover costs from other PRPs. We hold that it does.

															I

															A

															   Courts have frequently grappled
with whether and how PRPs may recoup CERCLA-related costs from
other PRPs. The questions lie at the intersection of two statutory
provisions—CERCLA §§107(a) and 113(f). Section 107(a) defines four
categories of PRPs, 94 Stat. 2781, 42 U. S. C.
§§9607(a)(1)–(4), and makes them liable for, among other
things:

															   “(A) all costs of removal or
remedial action incurred by the United States Government or a State
or an Indian tribe not inconsistent with the national contingency
plan; [and]

															   “(B) any other necessary costs of response
incurred by any other person consistent with the national
contingency plan.” §9607(a)(4)(A)–(B).

															Enacted as part of the Superfund Amendments and
Reauthorization Act of 1986 (SARA), 100 Stat. 1613, §113(f)
authorizes one PRP to sue another for contribution in certain
circumstances. 42 U. S. C. §9613(f).[ Footnote 1 ]

															   Prior to the advent of §113(f)’s express
contribution right, some courts held that §107(a)(4)(B) provided a
cause of action for a private party to recover voluntarily incurred
response costs and to seek contribution after having been sued. See Cooper Industries, supra , at 161–162 (collecting cases); Key Tronic Corp. v. United States , 511 U. S. 809 , 816, n. 7 (1994)
same. After SARA’s enactment, however, some Courts of Appeals
believed it necessary to “direc[t] traffic between” §107(a) and
§113(f). 459 F. 3d 827, 832 (CA8 2006) (case below). As a
result, many Courts of Appeals held that §113(f) was the exclusive
remedy for PRPs. See Cooper Industries, supra , at 169
(collecting cases). But as courts prevented PRPs from suing under
§107(a), they expanded §113(f) to allow PRPs to seek “contribution”
even in the absence of a suit under §106 or §107(a). Aviall
Servs., Inc. v. Cooper Industries, Inc. , 312
F. 3d 677, 681 (CA5 2002) (en banc).

															   In Cooper Industries , we held that a
private party could seek contribution from other liable parties
only after having been sued under §106 or §107(a). 543 U. S., at
161. This narrower interpretation of §113(f) caused several Courts
of Appeals to reconsider whether PRPs have rights under
§107(a)(4)(B), an issue we declined to address in Cooper
Industries . Id. , at 168. After revisiting the issue,
some courts have permitted §107(a) actions by PRPs. See Consolidated Edison Co. of N. Y. v. UGI
Utilities, Inc. , 423 F. 3d 90 (CA2 2005); Metropolitan Water Reclamation Dist. of Greater Chicago v. North American Galvanizing & Coatings, Inc. , 473
F. 3d 824 (CA7 2007). However, at least one court continues to
hold that §113(f) provides the exclusive cause of action available
to PRPs. E. I. Dupont de Nemours & Co. v. United
States , 460 F. 3d 515 (CA3 2006). Today, we resolve this
issue.

															B

															   In this case, respondent Atlantic
Research leased property at the Shumaker Naval Ammunition Depot, a
facility operated by the Department of Defense. At the site,
Atlantic Research retrofitted rocket motors for petitioner United
States. Using a high-pressure water spray, Atlantic Research
removed pieces of propellant from the motors. It then burned the
propellant pieces. Some of the resultant wastewater and burned fuel
contaminated soil and groundwater at the site.

															   Atlantic Research cleaned the
site at its own expense and then sought to recover some of its
costs by suing the United States under both §107(a) and §113(f).
After our decision in Cooper Industries foreclosed relief
under §113(f), Atlantic Research amended its complaint to seek
relief under §107(a) and federal common law. The United States
moved to dismiss, arguing that §107(a) does not allow PRPs (such as
Atlantic Research) to recover costs. The District Court granted the
motion to dismiss, relying on a case decided prior to our decision
in Cooper Industries , Dico, Inc. v. Amoco Oil
Co. , 340 F. 3d 525 (CA8 2003).

															   The Court of Appeals for the Eighth Circuit
reversed. Recognizing that Cooper Industries undermined
the reasoning of its prior precedent, 459 F. 3d, at 830,
n. 4, the Court of Appeals joined the Second and Seventh
Circuits in holding that §113(f) does not provide “the exclusive
route by which [PRPs] may recover cleanup costs.” Id., at
834 (citing Consolidated Edison Co. , supra ). The
court reasoned that §107(a)(4)(B) authorized suit by any person
other than the persons permitted to sue under §107(a)(4)(A). 459
F. 3d, at 835. Accordingly, it held that §107(a)(4)(B)
provides a cause of action to Atlantic Research. To prevent
perceived conflict between §107(a)(4)(B) and §113(f)(1), the Court
of Appeals reasoned that PRPs that “have been subject to §§106 or
107 enforcement actions are still required to use §113, thereby
ensuring its continued vitality.” Id. , at 836–837. We
granted certiorari, 549 U. S. ___ (2007), and now affirm.

															II

															A

															   The parties’ dispute centers on
what “other person[s]” may sue under §107(a)(4)(B). The Government
argues that “any other person” refers to any person not identified
as a PRP in §§107(a)(1)–(4).[ Footnote 2 ] In other words, subparagraph (B) permits suit
only by non-PRPs and thus bars Atlantic Research’s claim. Atlantic
Research counters that subparagraph (B) takes its cue from
subparagraph (A), not the earlier paragraph (1)–(4). In accord with
the Court of Appeals, Atlantic Research believes that subparagraph
(B) provides a cause of action to anyone except the United States,
a State, or an Indian tribe—the persons listed in subparagraph (A).
We agree with Atlantic Research.

															   Statutes must “be read as a
whole.” King v. St. Vincent’s Hospital , 502 U. S. 215 , 221
(1991). Applying that maxim, the language of suparagraph (B) can be
understood only with reference to subparagraph (A). The provisions
are adjacent and have remarkably similar structures. Each concerns
certain costs that have been incurred by certain entities and that
bear a specified relationship to the national contingency
plan.[ Footnote 3 ] Bolstering
the structural link, the text also denotes a relationship between
the two provisions. By using the phrase “other necessary costs,”
subparagraph (B) refers to and differentiates the relevant costs
from those listed in subparagraph (A).

															   In light of the relationship between the
subparagraph, it is natural to read the phrase “any other person”
by referring to the immediately preceding subparagraph (A), which
permits suit only by the United States, a State, or an Indian
tribe. The phrase “any other person” therefore means any person
other than those three. See 42 U. S. C. §9601(21) (defining
“person” to include the United States and the various States).
Consequently, the plain language of subparagraph (B) authorizes
cost-recovery actions by any private party, including PRPs. See Key Tronic , 511 U. S., at 818 (stating in dictum that §107
“impliedly authorizes private parties to recover cleanup costs from other PRP[s]” (emphasis added)).

															   The Government’s interpretation makes little
textual sense. In subparagraph (B), the phrase “any other necessary
costs” and the phrase “any other person” both refer to
antecedents—“costs” and “person[s]”—located in some previous
statutory provision. Although “any other necessary costs” clearly
references the costs in subparagraph (A), the Government would
inexplicably interpret “any other person” to refer not to the
persons listed in subparagraph (A) but to the persons listed as
PRPs in paragraphs (1)–(4). Nothing in the text of §107(a)(4)(B)
suggests an intent to refer to antecedents located in two different
statutory provisions. Reading the statute in the manner suggested
by the Government would destroy the symmetry of §§107(a)(4)(A) and
(B) and render subparagraph (B) internally confusing.

															   Moreover, the statute defines PRPs so broadly
as to sweep in virtually all persons likely to incur cleanup costs.
Hence, if PRPs do not qualify as “any other person” for purposes of
§107(a)(4)(B), it is unclear what private party would. The
Government posits that §107(a)(4)(B) authorizes relief for
“innocent” private parties—for instance, a landowner whose land has
been contaminated by another. But even parties not responsible for
contamination may fall within the broad definitions of PRPs in
§§107(a)(1)–(4). See 42 U. S. C. §9607(a)(1) (listing “the
owner and operator of a … facility” as a PRP); see also United
States v. Alcan Aluminum Corp. , 315 F. 3d 179,
184 (CA2 2003) (“CERCLA §9607 is a strict liability statute”). The
Government’s reading of the text logically precludes all PRPs,
innocent or not, from recovering cleanup costs. Accordingly,
accepting the Government’s interpretation would reduce the number
of potential plaintiffs to almost zero, rendering §107(a)(4)(B) a
dead letter.[ Footnote 4 ] See Louisville & Nashville R. Co. v. Mottley , 219 U. S. 467 ,
475 (1911) (“We must have regard to all the words used by Congress,
and as far as possible give effect to them”).

															   According to the Government, our
interpretation suffers from the same infirmity because it causes
the phrase “any other person” to duplicate work done by other text.
In the Government’s view, the phrase “any other necessary costs”
“already precludes governmental entities from recovering under”
§107(a)(4)(B). Brief for United States 20. Even assuming the
Government is correct, it does not alter our conclusion. The phrase
“any other person” performs a significant function simply by
clarifying that subparagraph (B) excludes the persons enumerated in
subparagraph (A). In any event, our hesitancy to construe statutes
to render language superfluous does not require us to avoid
surplusage at all costs. It is appropriate to tolerate a degree of
surplusage rather than adopt a textually dubious construction that
threatens to render the entire provision a nullity.

															B

															   The Government also argues that
our interpretation will create friction between §107(a) and
§113(f), the very harm courts of appeals have previously tried to
avoid. In particular, the Government maintains that our
interpretation, by offering PRPs a choice between §107(a) and
§113(f), effectively allows PRPs to circumvent §113(f)’s shorter
statute of limitations. See 42 U. S. C. §§9613(g)(2)–(3).
Furthermore, the Government argues, PRPs will eschew equitable
apportionment under §113(f) in favor of joint and several liability
under §107(a). Finally, the Government contends that our
interpretation eviscerates the settlement bar set forth in
§113(f)(2).

															   We have previously recognized
that §§107(a) and 113(f) provide two “clearly distinct” remedies. Cooper Industries , 543 U. S., at 163, n. 3. “CERCLA
provide[s] for a right to cost recovery in certain
circumstances, §107(a), and separate rights to
contribution in other circumstances, §§113(f)(1),
113(f)(3)(B).” Id. , at 163 (emphases added). The
Government, however, uses the word “contribution” as if it were
synonymous with any apportionment of expenses among PRPs. Brief for
United States 33, n. 14 (“Contribution is merely a form of
cost recovery, not a wholly independent type of relief”); see also, e.g. , Pinal Creek Group v. Newmont Mining
Corp. , 118 F. 3d 1298, 1301 (CA9 1997) (“Because all PRPs
are liable under the statute, a claim by one PRP against another
PRP necessarily is for contribution”). This imprecise usage
confuses the complementary yet distinct nature of the rights
established in §§107(a) and 113(f).

															   Section 113(f) explicitly grants PRPs a right
to contribution. Contribution is defined as the “tortfeasor’s right
to collect from others responsible for the same tort after the
tortfeasor has paid more than his or her proportionate share, the
shares being determined as a percentage of fault.” Black’s Law
Dictionary 353 (8th ed. 1999). Nothing in §113(f) suggests that
Congress used the term “contribution” in anything other than this
traditional sense. The statute authorizes a PRP to seek
contribution “during or following” a suit under §106 or §107(a). 42
U. S. C. §9613(f)(1).[ Footnote
5 ] Thus, §113(f)(1) permits suit before or after the
establishment of common liability. In either case, a PRP’s right to
contribution under §113(f)(1) is contingent upon an inequitable
distribution of common liability among liable parties.

															   By contrast, §107(a) permits recovery of
cleanup costs but does not create a right to contribution. A private party may recover under §107(a) without any
establishment of liability to a third party. Moreover, §107(a)
permits a PRP to recover only the costs it has “incurred” in
cleaning up a site. 42 U. S. C. §9607(a)(4)(B). When a party
pays to satisfy a settlement agreement or a court judgment, it does
not incur its own costs of response. Rather, it reimburses other
parties for costs that those parties incurred. Accordingly, the remedies
available in §§107(a) and 113(f) complement each other by providing
causes of action “to persons in different procedural
circumstances.” Consolidated Edison , 423 F. 3d, at
99; see also E. I. Dupont de Nemours , 460 F. 3d, at
548 (Sloviter, J., dissenting). Section 113(f)(1) authorizes a
contribution action to PRPs with common liability stemming from an
action instituted under §106 or §107(a). And §107(a) permits cost
recovery (as distinct from contribution) by a private party that
has itself incurred cleanup costs. Hence, a PRP that pays money to
satisfy a settlement agreement or a court judgment may pursue
§113(f) contribution. But by reimbursing response costs paid by
other parties, the PRP has not incurred its own costs of response
and therefore cannot recover under §107(a). As a result, though
eligible to seek contribution under §113(f)(1), the PRP cannot
simultaneously seek to recover the same expenses under §107(a).
Thus, at least in the case of reimbursement, the PRP cannot choose
the 6-year statute of limitations for cost-recovery actions over
the shorter limitations period for §113(f) contribution
claims.[ Footnote 6 ] For similar reasons, a PRP could
not avoid §113(f)’s equitable distribution of reimbursement costs
among PRPs by instead choosing to impose joint and several
liability on another PRP in an action under §107(a).[ Footnote 7 ] The choice of remedies simply
does not exist. In any event, a defendant PRP in such a §107(a)
suit could blunt any inequitable distribution of costs by filing a
§113(f) counterclaim. 459 F. 3d, at 835; see also Consolidated Edison, supra , at 100, n. 9 (collecting
cases). Resolution of a §113(f) counter-claim would necessitate the
equitable apportionment of costs among the liable parties,
including the PRP that filed the §107(a) action. 42 U. S. C.
§9613(f)(a) (“In resolving contribution claims, the court may
allocate response costs among liable parties using such equitable
factors as the court determines are appropriate”). Finally, permitting PRPs to seek
recovery under §107(a) will not eviscerate the settlement bar set
forth in §113(f)(2). That provision prohibits §113(f) contribution
claims against “[a] person who has resolved its liability to the
United States or a State in an administrative or judicially
approved settlement … .” 42 U. S. C. §9613(f)(2). The
settlement bar does not by its terms protect against cost-recovery
liability under §107(a). For several reasons, we doubt this
supposed loophole would discourage settlement. First, as stated
above, a defendant PRP may trigger equitable apportionment by
filing a §113(f) counterclaim. A district court applying
traditional rules of equity would undoubtedly consider any prior
settlement as part of the liability calculus. Cf. Restatement
(Second) of Torts §886A(2), p. 337 (1977) (“No tortfeasor can be
required to make contribution beyond his own equitable share of the
liability”). Second, the settlement bar continues to provide
significant protection from contribution suits by PRPs that have
inequitably reimbursed the costs incurred by another party. Third,
settlement carries the inherent benefit of finally resolving
liability as to the United States or a State.[ Footnote 8 ] III Because the plain
terms of §107(a)(4)(B) allow a PRP to recover costs from other
PRPs, the statute provides Atlantic Research with a cause of
action. We therefore affirm the judgment of the Court of
Appeals. It is so ordered. Footnote 1 Section 113(f)(1) permits private
parties to seek contribution during or following a civil action
under §106 or §107(a). 42 U. S. C. §9613(f)(1). Section
113(f)(3)(B) permits private parties to seek contribution after
they have settled their liability with the Government.
§9613(f)(3)(B). Footnote 2 CERCLA §107(a) lists four broad
categories of persons as PRPs, by definition liable to other
persons for various costs: “(1) the owner and operator of a vessel or a
facility, “(2) any person who at the time of disposal of any
hazardous substance owned or operated any facility at which such
hazardous substances were disposed of, “(3) any person who by contract, agreement, or
otherwise arranged for disposal or treatment, or arranged with a
transporter for transport for disposal or treatment, of hazardous
substances owned or possessed by such person, by any other party or
entity, at any facility or incineration vessel owned or operated by
another party or entity and containing such hazardous substances,
and “(4) any person who accepts or accepted any
hazardous substances for transport to disposal or treatment
facilities, incineration vessels or sites selected by such person,
from which there is a release, or a threatened release which causes
the incurrence of response costs, of a hazardous substance, shall
be liable for [various costs].” 42 U. S. C.
§§9607(a)(1)–(4). Footnote 3 “The national contingency plan
specifies procedures for preparing and responding to contaminations
and was promulgated by the Environmental Protection Agency
… .” Cooper Industries Inc. v. Aviall Services,
Inc., 543 U. S. 157 , 161, n. 2 (2004)
(citing 40 CFR pt. 300 (2004)). Footnote 4 Congress amended the statute in
2002 to exempt some bona fide prospective purchasers (BFPPs) from
liability under §107(a). See 42 U. S. C. §9607(r)(1) (2000
ed., Supp. IV). The Government claims that these persons are
non-PRPs and therefore qualify as “any other person” under its
interpretation of §107(a)(4)(B). Prior to 2002, however, the
statute made this small set of persons liable as PRPs. Accordingly,
even if BFPPs now give some life to the Government’s interpretation
of §107(a)(4)(B), it would be implausible at best to conclude that
§107(a)(4)(B) lay dormant until the enactment of §107(r)(1) in
2002. Footnote 5 Similarly, §113(f)(3)(B) permits
a PRP to seek contribution after it “has resolved its liability to
the United States or a State … in an administrative or judicially
approved settlement … .” 42 U. S. C.
§9613(f)(3)(B). Footnote 6 We do not suggest that
§§107(a)(4)(B) and 113(f) have no overlap at all. Key Tronic
Corp. v. United States, 511 U. S. 809 , 816 (1994) (stating the
statutes provide “similar and somewhat overlapping remed[ies]”).
For instance, we recognize that a PRP may sustain expenses pursuant
to a consent decree following a suit under §106 or §107(a). See, e.g. , United Technologies Corp. v. Browning-Ferris Industries , Inc., 33 F. 3d 96, 97
(CA1 1994). In such a case, the PRP does not incur costs
voluntarily but does not reimburse the costs of another party. We
do not decide whether these compelled costs of response are
recoverable under §113(f), §107(a), or both. For our purposes, it
suffices to demonstrate that costs incurred voluntarily are
recoverable only by way of §107(a)(4)(B), and costs of
reimbursement to another person pursuant to a legal judgment or
settlement are recoverable only under §113(f). Thus, at a minimum,
neither remedy swallows the other, contrary to the Government’s
argument. Footnote 7 We assume without deciding that
§107(a) provides for joint and several liability. Footnote 8 Because §107(a) expressly permits
PRPs to seek cost recovery, we need not address the alternative
holding of the Court of Appeals that §107(a) contains an additional
implied right to contribution for PRPs who are not eligible for
relief under §113(f). Cf. Cooper Industries , 543 U. S., at
171 (citing Texas Industries, Inc. v. Radcliff
Materials, Inc. , 451 U. S. 630 (1981); Northwest Airlines, Inc. v. Transport Workers , 451 U. S. 77 (1981)).

Summary: In United States v. Atlantic Research Corp. (2007), the Supreme Court held that the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) allows private parties, known as potentially responsible parties (PRPs), to recover costs associated with cleaning up contaminated sites from other PRPs under Section 107(a) of the act. This decision clarified the relationship between Section 107(a) and Section 113(f) of CERCLA, holding that PRPs can use Section 107(a) to recover costs voluntarily incurred during the cleanup process, while Section 113(f) allows PRPs to seek contribution after being sued or settling with the government.