United States Court of Appeals
FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued April 24, 2001 Decided July 24, 2001
No. 99-1457
Cement Kiln Recycling Coalition, et al.,
Petitioners
v.
Environmental Protection Agency and
Christine Todd Whitman, Administrator,
Respondents
Dow Chemical Company, et al.,
Intervenors
Consolidated with
99-1477, 99-1480, 99-1483, 99-1485, 99-1486,
99-1490, 99-1491, 99-1492, 99-1493, 99-1494,
99-1495, 99-1496, 99-1497, 99-1498
On Petitions for Review of an Order of the
Environmental Protection Agency
---------
James S. Pew argued the cause for petitioner Sierra Club.
With him on the briefs was Howard I. Fox.
Jeremiah J. Jewett, III, David P. Novello, Ronald A.
Shipley, and Scott H. Segal argued the cause for Industry
Petitioners. With them on the briefs were Richard G. Stoll,
Michael W. Steinberg, Terry J. Satterlee, Alok Ahuja, Karl S.
Bourdeau, David M. Friedland, Aaron H. Goldberg, Lisa M.
Jaeger, David R. Case, Thomas G. Echikson, James N.
Cahan, William M. Bumpers, David A. Smart, and Douglas
H. Green.
David R. Case argued the cause and filed the briefs for
petitioner Environmental Technology Council.
Richard G. Stoll, David P. Novello, Michael W. Steinberg,
Ronald A. Shipley, Karl S. Bourdeau, David M. Friedland,
Aaron H. Goldberg, Scott H. Segal, Lisa M. Jaeger, David R.
Case, William M. Bumpers, and Jeremiah J. Jewett, III were
on the brief for industry intervenors. Joshua D. Sarnoff
entered an appearance.
Lois Godfrey Wye and Norman L. Rave, Jr., Attorneys,
U.S. Department of Justice, and Steven E. Silverman, Attor-
ney, Environmental Protection Agency, argued the cause for
respondents. With them on the brief was Lois J. Schiffer,
Assistant Attorney General at the time the brief was filed,
U.S. Department of Justice. Christopher S. Vaden, Attorney,
U.S. Department of Justice, entered an appearance.
James S. Pew and Howard I. Fox were on the brief for
intervenor Sierra Club.
David R. Case was on the brief for intervenor Environmen-
tal Technology Council.
Before: Randolph, Rogers and Tatel, Circuit Judges.
Opinion for the Court filed Per Curiam.*
Per Curiam: In this case, industry and environmental
petitioners challenge EPA air pollution standards for hazard-
__________
* Judge Tatel wrote Parts I, II, III, IV, and VII; Judge Ran-
dolph wrote Parts V and VI.
ous waste combustors. Because the standards fail to reflect
the emissions achieved in practice by the best-performing
sources as required by the Clean Air Act, we remand to the
Agency for further proceedings. In all other respects, we
deny the petitions for review.
I
Until 1990, the Clean Air Act ("CAA"), 42 U.S.C. ss 7401-
7671q, required the Environmental Protection Agency to set
risk-based air pollution standards that would provide an
"ample margin of safety to protect the public health." Id.
s 7412(b)(1)(B) (1990); see also H.R. Rep. No. 101-490, at
151, 322 (1990). To address problems with the implementa-
tion of risk-based regulation, Congress amended the Act in
1990 to require EPA to set the most stringent standards
achievable, 42 U.S.C. s 7412(d)(2), that is, standards "based
on the maximum reduction in emissions which can be
achieved by application of [the] best available control technol-
ogy." S. Rep. No. 101-228, at 133 (1989).
The 1990 amendments included the provision at issue in
this case--42 U.S.C. s 7412(d)--which directs EPA to set
standards limiting emissions of listed hazardous air pollutants
("HAPs"), id. ss 7412(b), (c)(1)-(2), from major stationary
sources. Section 7412(d)(2) provides that:
Emission standards ... shall require the maximum de-
gree of reduction in emissions of the hazardous air
pollutants subject to this section ... that the Administra-
tor, taking into consideration the cost of achieving such
emission reduction, and any non-air quality health and
environmental impacts and energy requirements, deter-
mines is achievable for new or existing sources....
Supplementing this general guidance, Congress imposed min-
imum stringency requirements--EPA calls them "emission
floors"--which "apply without regard to either costs or the
other factors and methods listed in section 7412(d)(2)." Nat'l
Lime Ass'n v. EPA, 233 F.3d 625, 629 (D.C. Cir. 2000)
("National Lime II"). For "new sources"--factories or other
sources on which construction begins after EPA publishes
emission standards, 42 U.S.C. s 7411(a)(2)--"[t]he maximum
degree of reduction in emissions that is deemed achievable
... shall not be less stringent than the emission control that
is achieved in practice by the best controlled similar
source...." Id. s 7412(d)(3). For existing sources, what
EPA deems achievable "shall not be less stringent than[ ] the
average emission limitation achieved by the best performing
12 percent of the existing sources (for which the Administra-
tor has emissions information)...." Id. As we explained in
National Lime II, EPA implements these requirements
through a two-step process: the Agency first sets emission
floors for each pollutant and source category and then deter-
mines whether stricter standards, known as "beyond-the-
floor" limits, are achievable in light of the factors listed in
section 7412(d)(2). 233 F.3d at 629.
Hazardous waste combustors ("HWCs"), the focus of this
case, are also subject to regulation under the Resource Con-
servation and Recovery Act ("RCRA"), 42 U.S.C. ss 6901-
6992k, which "establishes a comprehensive 'cradle to grave'
regulatory program for the treatment, storage, and disposal
of hazardous waste." Horsehead Res. Dev. Co. v. Browner,
16 F.3d 1246, 1252 (D.C. Cir. 1994). A pre-1990 risk-based
statute, RCRA directs EPA to set standards for hazardous
waste-burning facilities that "protect human health and the
environment." 42 U.S.C. s 6924(q)(1). Both Congress and
EPA have acknowledged the overlap between RCRA and the
CAA. Indeed, the CAA itself directs the Administrator to
"take into account any regulations of such emissions which
are promulgated under [RCRA] and ... to the maximum
extent practicable ... ensure that the requirements of
[RCRA] and [section 7412] are consistent." Id. s 7412(n)(7).
Hazardous waste combustors must have RCRA permits for
stack air emissions until they can demonstrate compliance
with CAA standards through required tests; once a source
complies with the CAA, it no longer needs a separate RCRA
permit. Final Standards for Hazardous Air Pollutants for
Hazardous Waste Combustors, 64 Fed. Reg. 52,828, 52,833
(Sept. 30, 1999).
In 1999, acting pursuant to CAA section 7412(d) and follow-
ing notice and comment, EPA issued standards limiting emis-
sions from three types of HWCs: incinerators that destroy
hazardous waste; cement kilns that use hazardous waste as
fuel in the cement-manufacturing process; and lightweight
aggregate kilns that use hazardous waste as fuel to produce
lightweight aggregate concrete, a building material used for
structural purposes and thermal insulation. These HWCs
burn approximately 80% of the hazardous waste combusted
each year in the United States, id. at 52,832, emitting more
than 11,000 metric tons of HAPs.
For each type of HWC, i.e., each "source category," EPA
set standards for the following HAPs: dioxins; mercury; the
semi-volatile metals lead and cadmium; the low-volatility
metals chromium, arsenic, and beryllium; particulate matter;
chlorine; carbon monoxide; and hydrocarbons. All of these
HAPs can have serious health effects. Dioxin, mercury, and
semi-volatile metal emissions are of particular concern; expo-
sure can cause effects such as cancer, neurological and organ
damage, and impaired child development. See id. at 53,002-
03.
To set these standards, EPA, acting pursuant to section
7412(d)(3), began by setting emission floors for new and
existing sources--EPA calls them "MACT (maximum achiev-
able control technology) floors." After assembling a database
of sources and their emission levels recorded primarily during
RCRA compliance tests, the Agency went through the follow-
ing steps for each HAP in each source category. For existing
sources, EPA identified the best-performing 12 percent of
sources, creating what it calls the "MACT pool." EPA then
identified the primary emission control technology used by
sources in the MACT pool with emission levels equivalent to
or lower than the pool's median. It labeled that technology
the "MACT control." For some HAPs, EPA chose end-of-
stack pollution control technology as the MACT control; for
other HAPs, the Agency chose the technique of "feedrate"--
the rate at which source operators feed hazardous waste into
combustors. EPA next expanded the MACT pool to include
all sources using the MACT control (provided the control was
well-designed and properly operated) and set the MACT floor
at the worst emission level achieved by any source in that
expanded pool. For new sources, EPA used the same meth-
odology but chose as the MACT control the technology used
by the best-performing source for which it had information.
After setting forty-nine floors, EPA considered, as required
by section 7412(d)(2), whether stricter limits--"beyond-the-
floor" standards--would be achievable. Taking into account
cost, energy requirements, and certain non-air quality health
and environmental impacts, EPA ultimately set five beyond-
the-floor standards.
Environmental and industry petitioners now challenge the
HWC emission standards. The Sierra Club argues that:
(1) the MACT approach results in emission standards that
violate section 7412(d)(3) because they fail to reflect the
emissions achieved in practice by the best-performing
sources; (2) the Agency violated the Act by basing standards
on RCRA test data, which are generated under worst-case
conditions; and (3) in making beyond-the-floor determina-
tions, the Agency failed to consider certain "non-air quality
health and environmental impacts" as required by section
7412(d)(2) and arbitrarily and capriciously refused to consider
tougher standards based on additional controls for some
HAPs. Industry petitioners contend that EPA violated sec-
tion 7412(d)(3)(A) by basing existing-source floors on actual
emissions data rather than on existing regulatory require-
ments, such as RCRA permit limits. Industry petitioners
also challenge as arbitrary and capricious many individual
emission standards, as well as several monitoring and imple-
mentation regulations. One industry petitioner, Continental
Cement, argues that EPA violated the Regulatory Flexibility
Act, 5 U.S.C. ss 601-612. Another petitioner, the Environ-
mental Technology Council, challenges EPA's adoption of
procedures that permit sources to petition the Agency for
alternative requirements if they cannot meet MACT stan-
dards due to raw material contributions to emissions. See 40
C.F.R. ss 63.1206(b)(9) & (10).
II
We begin with industry petitioners' argument that EPA
violated CAA section 7412(d)(3)(A) by basing existing-source
standards on emissions data rather than RCRA or other
permit limits. Section 7412(d)(3)(A) provides that "[e]mission
standards promulgated ... for existing sources ... shall not
be less stringent ... than[ ] the average emission limitation
achieved by the best performing 12 percent of the existing
sources (for which the Administrator has emissions informa-
tion)...." 42 U.S.C. s 7412(d)(3)(A). Focusing on the
phrase "emission limitation," petitioners point out that CAA
section 7602(k) defines that term as "a requirement estab-
lished by the State or the Administrator which limits the
quantity, rate, or concentration of emissions of air pollu-
tants...." Id. s 7602(k). According to petitioners, section
7412(d)(3)(A) must therefore be read as follows: "[e]mission
standards promulgated ... for existing sources ... shall not
be less stringent ... than the average state or federal re-
quirement limiting emissions of a pollutant achieved in
practice by the best performing 12 percent of the existing
sources." Indus. Petitioners' Opening Br. at 8.
Although EPA disputes this reading of the statute--it
contends that CAA section 7412(d)(3)(A)'s use of the word
"achieved" indicates that standards must be based on actual
emissions data--the Agency argues that we may not even
consider petitioners' argument because they failed to present
it to the Agency during the rulemaking. See 42 U.S.C.
s 7607(d)(7)(B) ("Only an objection to a rule or procedure
which was raised with reasonable specificity during the period
for public comment ... may be raised during judicial re-
view."). Having reviewed each page of the record petitioners
cite to demonstrate that they presented their interpretation
of section 7412(d)(3)(A) during the rulemaking, we agree with
EPA. The first cited comment argued only that the Agency
should set the standard for particulate matter emissions from
lightweight aggregate kilns at the same level as existing New
Source Performance Standards ("NSPS"), to which EPA re-
sponded that "[w]e rejected the NSPS as the basis for the
floor emission level because our MACT analysis of data from
existing sources indicates that a particulate matter floor level
lower than the NSPS is currently being achieved in prac-
tice...." Final Response to Comments to the Proposed
HWC MACT Standards, Vol. I: Standards ("1 Final Re-
sponse to Comments"): LWAK Standards, at 13-14 (July
1999). The second cited comment stated only that "[t]he
MACT floor should be set based on projections of Tier I
allowable mercury feedrate limits," to which EPA responded,
"[w]e agree that BIF Tier I feedrate limits could be consid-
ered as a floor control option. We conclude, however, that
those allowable feedrate limits are much higher than actual
feedrate levels ... and thus do not represent MACT." Id.
Cement Kilns Mercury, at 7. As the Agency points out, these
comments "merely argued that EPA could permissibly con-
sider RCRA permit limitations in establishing floors," Re-
spondent's Br. at 51, not (as petitioners now argue) that
section 7412(d)(3)(A) requires existing-source floors to be
based on permit limits. And the final page petitioners cite
says nothing at all about existing regulatory limits. See Final
Technical Support Document for HWC MACT Standards,
Vol. III: Selection of MACT Standards and Technologies, at
2-2 (July 1999) ("3 Final TSD").
In considering the extent to which a statutory interpreta-
tion must have been presented to an agency before a petition-
er can raise it here, we have said that:
[w]hile there are surely limits on the level of congruity
required between a party's arguments before an adminis-
trative agency and the court, respect for agencies' proper
role in the Chevron framework requires that the court be
particularly careful to ensure that challenges to an agen-
cy's interpretation of its governing statute are first
raised in the administrative forum.
Natural Res. Def. Council, Inc. v. EPA, 25 F.3d 1063, 1074
(D.C. Cir. 1994). Though we have recognized that "precisely
the same argument that was made before the agency [need
not] be rehearsed again, word for word, on judicial review,"
Appalachian Power Co. v. EPA, 135 F.3d 791, 818 (D.C. Cir.
1998), petitioners point us to nothing in the record even
hinting that the phrase "emission limitation" must be defined
by reference to section 7602(k). EPA (as opposed to its
appellate counsel) has not had "the first opportunity to bring
its expertise to bear on the resolution" of this question. Id.
III
The Sierra Club also challenges EPA's interpretation of
CAA section 7412(d)(3), but on different grounds. The Sierra
Club argues that section 7412(d)(3) requires floors to reflect
emissions actually "achieved" by the best-performing sources,
and that EPA violated the statute by setting floors the
Agency considered achievable by all sources using MACT
technology. See, e.g., 1 Final Response to Comments: MACT
Floor Approaches, at 54-55 ("[W]e do not agree that the
proper interpretation of the CAA would require that the
MACT standards be based solely on an analysis of the
emissions levels being achieved by the best performing 12%
of sources.... MACT standard[s] must be achievable by all
sources judged to be using MACT or MACT equivalent
technology."). According to the Sierra Club, the contrast
between the language of section 7412(d)(2), which requires
the maximum degree of reduction "achievable," and section
7412(d)(3), which establishes that what EPA deems achievable
"shall not be less stringent" than what certain sources actual-
ly "achieve[ ]," demonstrates that "Congress was well aware
of the difference between what EPA believes to be 'achiev-
able' through the use of a particular technology and what the
relevant sources actually 'achieved.' " Sierra Club's Opening
Br. at 20. "EPA's insistence that [section 7412] floors must
reflect what the agency determines to be achievable through
the use of a particular technology," the Sierra Club concludes,
"boils down to an attempt to nullify the objective limits that
Congress deliberately placed on EPA's standard setting dis-
cretion by enacting [section 7412]'s mandatory floor provi-
sions in the 1990 Amendments." Id. at 21-22.
Defending its achievability rationale, EPA argues that sec-
tion 7412(d)(3)'s floor provision "is a gloss" on section
7412(d)(2), which establishes the achievability requirement.
Respondent's Br. at 23. According to the Agency, section
7412(d)(3) incorporates section 7412(d)(2)'s achievability stan-
dard. For this reason, EPA explains, it designed the MACT
approach to produce achievable standards.
We agree with the Sierra Club. Though section 7412(d)(2)
does direct EPA to require the "maximum emission reduc-
tion" that it determines to be achievable, section 7412(d)(3)
provides that "the maximum degree of reduction in emissions
that is deemed achievable ... shall not be less stringent
than" what the best-performing sources "achieve[ ]." Section
7412(d)(3) therefore limits the scope of the word "achievable"
in section 7412(d)(2). While standards achievable by all
sources using the MACT control might also ultimately reflect
what the statutorily relevant sources achieve in practice, EPA
may not deviate from section 7412(d)(3)'s requirement that
floors reflect what the best performers actually achieve by
claiming that floors must be achievable by all sources using
MACT technology. See Chevron U.S.A., Inc. v. Natural Res.
Def. Council, Inc., 467 U.S. 837, 842-43 (1984) (holding that if
Congress has spoken directly to the disputed issue of statuto-
ry construction, "that is the end of the matter; for the court,
as well as the agency, must give effect to the unambiguously
expressed intent of Congress").
This interpretation is required by our decisions in Sierra
Club v. EPA, 167 F.3d 658 (D.C. Cir. 1999), and National
Lime II, 233 F.3d 625. In Sierra Club, we held that CAA
section 7429(a)(2), which (in language virtually identical to the
terms of section 7412(d)(3)) directs EPA to set emission floors
for medical waste incinerators, requires EPA "to make a
reasonable estimate of the performance of the top 12 percent
of units." 167 F.3d at 662 (interpreting 42 U.S.C.
s 7429(a)(2), which requires that "[t]he degree of reduction in
emissions that is deemed achievable for new units in a
category shall not be less stringent than the emissions control
that is achieved in practice by the best controlled similar
unit," and that "[e]missions standards for existing units in a
category ... shall not be less stringent than the average
emissions limitation achieved by the best performing 12 per-
cent of units in the category"). While acknowledging that
EPA has authority to devise the means of deriving this
estimate, we made clear that the method the Agency selects
must "allow[ ] a reasonable inference as to the performance of
the top 12 percent of units." Id. at 663. We emphasized that
EPA must show not only that it believes its methodology
provides an accurate picture of the relevant sources' actual
performance, but also why its methodology yields the re-
quired estimate. Id. In evaluating EPA's new-source floors
in particular, which the Agency based on emission levels
achieved by the worst-performing sources using a given con-
trol technology, we concluded that EPA had not explained
"why the phrase 'best controlled similar unit' encompasses all
units using the same technology as the unit with the best
observed performance, rather than just that unit itself, as the
use of the singular in the statutory language suggests." Id.
at 665. In National Lime II, we addressed a Sierra Club
petition challenging emission standards set under section
7412(d) for non-hazardous waste-burning portland cement
kilns. In evaluating EPA's standards, we reiterated Sierra
Club's central holding that "to comply with the statute, EPA's
method of setting emission floors must reasonably estimate
the performance of the relevant best performing plants." 233
F.3d at 632 (citing Sierra Club, 167 F.3d at 665).
We thus turn to EPA's alternative argument: that the
MACT approach does in fact measure what the best-
performing sources actually achieve. According to EPA,
Sierra Club requires standards to reflect "the worst reason-
ably foreseeable performance of the best unit[s]," 167 F.3d at
665. EPA argues that to meet this requirement, as well as to
account for "inherent process variability in pollution control
devices," the Agency set the floors at the worst emission level
experienced by any source using the MACT control. Respon-
dent's Br. at 28. Indeed, EPA claims, Sierra Club actually
suggests that considering data from all sources using a
common control approach is a reasonable means of estimating
the performance of the best sources under the worst foresee-
able circumstances.
The Sierra Club disagrees, arguing that EPA has failed to
abide by Sierra Club because the Agency has not demonstrat-
ed that its floors based on the worst performers' emissions
reflect a reasonable estimate of the emissions achieved in
practice by the best-performing sources. As to new-source
floors, the Sierra Club contends that Sierra Club, by ques-
tioning whether EPA can represent "the performance of the
best performing source in the category with the performance
of the worst performing source that uses the same technolo-
gy[,].... casts serious doubt" on the legitimacy of the MACT
approach as a means of implementing section 7412(d)(3).
Sierra Club's Opening Br. at 27-28. Indeed, according to the
Sierra Club, "common use of one control technology provides
little or no reason to believe that the performance of the
worst performing source that was using that technology is in
any way representative of the best source's performance."
Id. at 29-30. The Sierra Club points to other factors, such as
the use of additional control techniques or of newer and
better versions of MACT technology, better training of opera-
tors, and better design and operation of the source itself, that
could all contribute to the best-performing source's level of
emissions. By failing to consider these factors, the Sierra
Club claims, EPA set floors that fail to reflect the estimates
required by CAA section 7412 and Sierra Club.
Applying the principles set forth in Sierra Club and Na-
tional Lime II, we again agree with the Sierra Club. To
begin with, Sierra Club permits EPA to account for variabili-
ty by setting floors at a level that reasonably estimates "the
performance of the 'best controlled similar unit' under the
worst reasonably foreseeable circumstances," 167 F.3d at 665,
not the worst foreseeable circumstances faced by any unit in
a given source category. Moreover, although Sierra Club
also notes that "[p]erhaps considering all units with the same
technology is justifiable because the best way to predict the
worst reasonably foreseeable performance of the best unit
with available data is to look at other units' performance," id.,
we explained in National Lime II that such an approach
would satisfy the statute "if pollution control technology were
the only factor determining emission levels of that HAP," 233
F.3d at 633 (emphasis added). Moreover, using language
especially relevant to this case, National Lime II observed
that:
it became clear [at oral argument] that the Sierra Club
believes that EPA's MACT approach would not accurate-
ly estimate emission levels of the best performing twelve
percent of plants if the best performing plants achieved
their emission levels not just by using technology, but
also by selecting cleaner manufacturing inputs. For
example, the best performing twelve percent of plants
might perform well because, in comparison to other
plants having the same technology, they use less-
polluting fuels or purer raw materials. Such plants
would have predictably lower emissions than plants using
MACT floor technology alone.
Id. at 632-33. National Lime II goes on to note that
although "this argument may well have merit," id. at 633, the
argument could not be considered because the Sierra Club
failed to present it in its opening brief, thus failing to explain
"why the emissions standards EPA set might not accurately
estimate the performance of the best performing twelve
percent of plants," id. at 632.
Here, unlike in National Lime II, the Sierra Club has
argued that factors other than MACT technology influence
emissions: "The best source may use other control techniques
that the worst source does not, may use a newer and better
version of the chosen technology, may train its operators
more rigorously, or may simply be better designed and
operated." Sierra Club's Opening Br. at 29. The statute
itself, the Sierra Club points out, directs EPA to consider
factors such as "process changes, substitution of materials or
other modifications ... design, equipment, work practice, or
operational standards ... [or] a combination of above," 42
U.S.C. ss 7412(d)(2)(A)-(E), suggesting that "Congress itself
recognized that many factors ... affect sources' emissions,"
Sierra Club's Opening Br. at 29. In addition, the Sierra Club
points to record evidence that other factors contribute to
emissions. For example, although EPA's particulate matter
floors for incinerators reflect what the Agency thought was
achievable with just one control technology--either a fabric
filter, an electrostatic precipitator, or an ionizing wet scrub-
ber, 64 Fed. Reg. at 52,864--record evidence suggests that
some incinerators use these devices in combination with other
control devices, see 3 Final TSD, at 4-2. As the Sierra Club
also observes, EPA has acknowledged that different models
of the same technology vary significantly in their perfor-
mance. See id. at 4-3 ("Fabric filters with conventional
woven fiberglass bags have demonstrated emissions control
levels on [incinerators].... With improved fiberglass or
Nomex felt and tri-loft fabrics, levels lower than 0.005 gr/dscf
have been demonstrated. High performance membrane fab-
rics ... have demonstrated levels below 0.0010 gr/dscf over
long term operation.").
The record contains still more indications that variables
other than the MACT control affect HWC emissions. For
example, in a 1996 technical support document, EPA ob-
served that "[t]he MACT [expanded pool] contains conditions
with a large range of [dioxin/furan] levels, from 0.005 to 38.5
TEQ ng/dscm. This indicates that the air pollution control
device system type ... may not be the only important
consideration[ ] affecting [dioxin/furan] control; other factors
such as combustion quality and waste composition ... may
also be of importance." Draft Technical Support Document
for HWC MACT Standards, Vol. III: Selection of MACT
Standards and Technologies, at 3-3 (Feb. 1996) ("3 Draft
TSD"). In a 1999 technical support document detailing its
strategy for estimating variability, EPA noted that "[t]he
MACT [expanded pools] typically contain data from a wide
variety of different sources within each HAP and source
category combination, thus capturing the potential range in
emissions due to differences in equipment operations, design,
waste type, etc." 3 Final TSD, at 2-17 to 2-18; see also 64
Fed. Reg. at 52,857. Commenters also brought to the Agen-
cy's attention factors other than the MACT control. One
commenter noted that:
[t]he data in the expanded MACT pools ... do not
provide meaningful information because many factors,
other than the type of control device, significantly affect
HWCs' emissions. Obvious examples of such factors
include feedrates, various operating parameters, operator
training and behavior, and variations between similar
(but not identical) control devices.... Because many
variables significantly influence emission rates, identify-
ing the emissions rates associated with a particular type
of control device indicates very little about the actual
capability of that type of control device.
1 Final Response to Comments: MACT Floor Approaches, at
51. EPA responded to this comment not by explaining why
these factors are insignificant to estimating emissions of the
best-performers, but rather by claiming (as it does here) that
floors must be achievable by all sources using MACT technol-
ogy. See id. at 53-55.
We think this record evidence supports the Sierra Club's
claim that because factors other than MACT technology
affect emissions, emissions of the worst-performing MACT
source may not reflect what the best-performers actually
achieve. EPA's responses are unpersuasive.
The Agency argues that "there is no question as to the type
of control device each source uses." Respondent's Br. at 38-
39. But as the Sierra Club points out, this claim is non-
responsive: just because EPA can identify which sources use
the MACT control does not mean that factors other than the
MACT control have no effect on emissions. The Agency also
emphasizes that it "considered only the variability consistent
with proper design and operation of MACT control." Id. at
39. Again, this claim misses the point: whether variability in
the MACT control accurately estimates variability associated
with the best-performing sources depends on whether factors
other than the MACT control contribute to emissions. In
other words, if factors other than MACT technology do
indeed influence a source's performance, it is not sufficient
that EPA considered sources using only well-designed and
properly operated MACT controls.
EPA next claims that even though the performance of the
MACT controls themselves vary, "effort[s] at further specifi-
cation [of the MACT control] failed because the myriad
factors that create operating variability proved impossible to
reliably quantify." Id. (citing 3 Draft TSD, at 2-6, which
notes that instead of setting the MACT control as any fabric
filter, the Agency could have differentiated among different
fabric filter units according to parameters such as "cloth type,
fabric age, cleaning practices, and pressure drop," but de-
clined to do so "due to lack of information" on specific
facilities' fabric filters). In a similar vein, the Agency claimed
in a 1996 technical support document (though not in this
court) that, at least in the case of the dioxin/furan standards,
factors other than technology that affect emissions, "such as
combustion quality and waste composition[,] ... are difficult
to quantify for the definition of MACT." 3 Draft TSD, at
3-3. Even accepting the proposition that factors affecting
source performance--either design features of the control
itself (such as the type of fabric used) or non-MACT variables
(such as waste composition or use of additional controls)--are
difficult to quantify when defining the MACT control, nothing
in the statute requires the Agency to use the MACT ap-
proach. Section 7412(d)(3) requires only that EPA set floors
at the emission level achieved by the best-performing sources.
If EPA cannot meet this requirement using the MACT
methodology, it must devise a different approach capable of
producing floors that satisfy the Clean Air Act. Indeed, the
very fact that EPA recognizes both design differences in
MACT technology and non-MACT factors as causes of wide-
ranging variations in performance suggests that the emissions
achieved by the worst-performing MACT source do not, as
the CAA requires, represent a reasonable estimate of emis-
sions achieved by the best-performing sources.
Finally, we are unpersuaded by EPA's claim that to ac-
count for the best-performing sources' operational variability,
it had to base the floors on the worst performers' emissions.
While we have recognized that a given control can experience
operational variability, see Nat'l Lime Ass'n v. EPA, 627 F.2d
416, 424-25, 436, 439-41 (D.C. Cir. 1980) (recognizing variabil-
ity in the performance of emission controls such as baghous-
es, ESPs, scrubbers, feed materials, and types of fuel), the
relevant question here is not whether control technologies
experience variability at all, but whether the variability expe-
rienced by the best-performing sources can be estimated by
relying on emissions data from the worst-performing sources
using the MACT control. In this case, the evidence EPA
cites to support the MACT approach as a means of account-
ing for operational variability fails to demonstrate the rele-
vant relationship. Some of the Agency's citations to the
record merely contain assertions that "[the] approach ...
fully accounts for normal process variability." 1 Final Re-
sponse to Comments: MACT Floor Approaches, at 59; see
also 64 Fed. Reg. at 52,923 (noting that HWCs are particular-
ly susceptible to variability). The actual variability data EPA
cites suggest only that emissions from sources using a given
control vary over a wide range, not that the high emission
levels achieved by sources at one end of that range reflect
levels achieved by sources at the other end, nor that the best-
performing sources ever experience a wide range of variabili-
ty at all. See, e.g., 3 Draft TSD, at 3-3 to 3-12, 4-2 to 4-8;
see also Final Technical Support Document for HWC MACT
Standards, Vol. IV: Compliance with the HWC MACT Stan-
dards, at 4-7 (July 1999) (explaining the operating parame-
ters of various control technologies). Indeed, throughout the
rulemaking, EPA defended its reliance on the worst-
performing MACT source as a means of setting achievable
floors, not as a way of determining the operational variability
experienced by the best-performing sources. See, e.g., 64
Fed. Reg. at 52,859 & n.77 (explaining that its decision to
base the floors "on the highest test condition average for
sources in the expanded MACT pool" was designed to ensure
that all sources using the MACT control could achieve the
standard).
What is more, statements in the record actually cast doubt
on the possibility that the emissions of the worst-performing
sources estimate the variability experienced by the best per-
formers. For example, in the introduction to the proposed
rule, EPA acknowledged that it considered a "12 percent
approach," according to which it would have set the floors
based on the statistical average of the 12 percent MACT pool
and then added the "average within-test condition variability
within the expanded MACT pool." Revised Standards for
Hazardous Waste Combustors, 61 Fed. Reg. 17,358, 17,367
(Apr. 19, 1996). EPA chose not even to propose this ap-
proach, however, concluding that "it could not be demonstrat-
ed that sources within the expanded MACT pool using MACT
floor controls could achieve the floor levels" that resulted
from the Agency's calculations. Id. The fact that EPA
calculated the variability experienced by the top 12 percent of
sources, but then declined to use those results to set the
floors because they would not be achievable by all MACT
sources, strongly suggests a real difference between emis-
sions achieved by the worst-performing sources and the varia-
bility experienced by the best performers. Similarly, EPA's
use of worst-case emissions data from RCRA compliance
tests, during which sources routinely spike their feed--a
practice we discuss in more detail in Part IV--further under-
mines the Agency's claim that to account for the variability
experienced by the best-performing sources, it had to set
floors based on the worst-performers' emissions: if, as the
Agency claims, RCRA data reflect sources' performance un-
der the worst foreseeable circumstances, why is the use of
worst-case data, on its own, insufficient to account for the
variability in emissions experienced by the best-performing
sources?
To sum up, the possibility we acknowledged in National
Lime II--that the "best performing plants achieve[ ] their
emission levels not just by using technology," 233 F.3d at
633--appears to have been borne out in this case. Because
record evidence suggests that factors other than the MACT
control influence emissions, EPA has not demonstrated, in
Sierra Club's words, that floors based on the worst-
performing MACT sources' emissions represent "a reasonable
estimate of the performance of the [best-performing] units."
167 F.3d at 662. To be sure, it is not our place to dictate to
the Agency how to account for variables other than the
MACT control. If in the case of a particular source category
or HAP, the Agency can demonstrate with substantial evi-
dence--not mere assertions--that MACT technology signifi-
cantly controls emissions, or that factors other than the
control have a negligible effect, the MACT approach could be
a reasonable means of satisfying the statute's requirements.
See Nat'l Lime II, 233 F.3d at 633. But even if, as EPA
claims, accounting for non-MACT factors is difficult, the
Agency may not use a proxy for the best performers that it
has considerable reason to believe falls short of section
7412(d)(3)'s requirements.
IV
As part of its challenge to the MACT approach, the Sierra
Club contends that EPA violated the Clean Air Act by relying
on "worst-case data" to derive the HWC standards. In
setting the floors, EPA relied on emissions data generated
during incinerator trial burn tests and RCRA compliance
testing of cement and lightweight aggregate kilns. During
such testing, sources often operate under worst-case condi-
tions by
spiking metals and chlorine in the waste feed [and]
detuning the emissions control equipment.... [T]hese
sources conduct tests in a manner that will establish a
wide envelope for their operating parameter limits in
order to accommodate the expected variability ... [in]
types of wastes, combustion system parameters, and
emission control parameters.
64 Fed. Reg. at 52,858. The Sierra Club argues that because
compliance data reflect abnormally bad performance, they
"do not represent any source's actual performance." Sierra
Club's Opening Br. at 23. Indeed, "sources' emissions during
normal operations tend to be less than one half of their
'worst-case' emissions." Id.
Defending its use of RCRA compliance data, EPA argues
that such data are in fact actual test results and therefore
reflect actual source performance. The fact that RCRA data
measure worst-case conditions, the Agency explains,
merely confirms that standards based on the data reflect
the most adverse conditions that can reasonably be ex-
pected to recur.... Because these test conditions are
specifically designed to help account for operating varia-
bility, they are more helpful than normal operating data
would be in estimating performance under a variety of
conditions and thus in helping to assure that properly
designed and operated sources can achieve the standard.
Respondent's Br. at 33 (internal quotation omitted). Accord-
ing to EPA, because the statute permits it to use available
information to identify the best-performing sources, and be-
cause RCRA data are available information, it reasonably
relied on RCRA test results.
Section 7412(d)(3) requires EPA to set emission floors
based on "the average emission limitation achieved by the
best performing 12 percent of the existing sources (for which
the Administrator has emissions information)." 42 U.S.C.
s 7412(d)(3)(A) (emphasis added). We think it not at all
unreasonable for the Agency to read this language as permit-
ting it to rely on "information" in its database--i.e., the
RCRA data. See Chevron, 467 U.S. at 843 ("[A] court may
not substitute its own construction of a statutory provision for
a reasonable interpretation made by the administrator of an
agency."). And as we pointed out in Sierra Club, "EPA
typically has wide latitude in determining the extent of data-
gathering necessary to solve a problem. We generally defer
to an agency's decision to proceed on the basis of imperfect
scientific information, rather than to invest the resources to
conduct the perfect study." 167 F.3d at 662 (internal quota-
tion omitted). Although sources do spike their feed during
RCRA compliance tests, the Sierra Club has offered us no
basis for concluding that using RCRA data would prevent
EPA from identifying the best-performers and predicting
their emissions under the "worst reasonably foreseeable cir-
cumstances." Id. at 665. In other words, the Sierra Club
has failed to demonstrate that EPA's model "bears no ration-
al relationship to the reality it purports to represent," Colum-
bia Falls Aluminum Co. v. EPA, 139 F.3d 914, 923 (D.C. Cir.
1998) (internal quotation omitted).
V
Industry petitioner Continental Cement claims that EPA
failed to meet its obligations under the Regulatory Flexibility
Act ("RFA"), as amended by the Small Business Regulatory
Enforcement Fairness Act of 1996 ("SBREFA"). Pub. L.
No. 96-354, 94 Stat. 1165-70 (1980), codified at 5 U.S.C.
ss 601-612, as amended by Pub. L. No. 104-121, 110 Stat.
864 (1996). Failure to comply with the RFA "may be, but
does not have to be, grounds for overturning a rule." Small
Refiner Lead Phase-Down Task Force v. EPA, 705 F.2d 506,
538 (D.C. Cir. 1983).
Under the RFA, agencies promulgating a rule that will
have a "significant impact" on "small entities" are required to
"prepare and make available for public comment an initial
regulatory flexibility analysis ... [that] describe[s] the impact
of the proposed rule" on those entities, and to publish a "final
regulatory analysis" with the final rule. 5 U.S.C. ss 605, 603,
604. Small entities include small businesses, small organiza-
tions, and small governmental jurisdictions. Id. s 601(6).
The regulatory analysis forces the agency to consider various
factors set forth in the statute, including "a description of the
steps the agency has taken to minimize the significant eco-
nomic impact [of the rule] on small entities." Id. s 604(a)
(final regulatory flexibility analysis); see also id. ss 603(b) &
(c) (initial regulatory flexibility analysis).
This procedure is intended to evoke commentary from
small businesses about the effect of the rule on their activi-
ties, and to require agencies to consider the effect of a
regulation on those entities. An agency may dispense with
the regulatory analysis if it certifies "that the rule will not, if
promulgated, have a significant economic impact on a sub-
stantial number of small entities." Id. s 605(b). EPA relied
on the s 605(b) exception.
In seeking to determine whether its regulations would have
"significant economic impact" on a "substantial number of
small entities," 64 Fed. Reg. at 53,023-24, EPA examined the
entities that would be "directly impacted"--hazardous waste
combustion facilities. EPA concluded that only six of the
HWC facilities met the definition of a "small business" and
that only two of these would experience compliance costs in
excess of one percent of annual sales. Id. at 53,024. EPA
therefore certified that there would be no significant impact
on a substantial number of small business HWC facilities.
Id. EPA then considered the economic effects of the new
rule on small businesses that generate and blend the hazard-
ous waste consumed in the HWCs. Id. EPA did not believe
the statute required it to conduct this inquiry, but it decided
to do so in the "spirit" of the RFA because some portion of
the burden of compliance might pass through to the genera-
tors and blenders of hazardous waste. Id. at 53,023-24. As
to these entities, EPA did not certify that there would be no
"significant impact" on a "substantial number" of small busi-
nesses. Id.
Continental claims that EPA should have considered each
category of HWCs separately in conducting its "direct im-
pact" analysis. Continental also maintains that EPA had to
certify that there would be no substantial effect on generators
of hazardous waste in order to meet the requirements of the
RFA. In response, EPA argues that it complied with the
requirements of the RFA.
Continental is a "cement manufacturer" under the relevant
Small Business Administration Regulations, and therefore
qualifies as a small business because it has fewer than 750
employees. Small Business Size Regulations, 65 Fed. Reg.
30,836, 30,847 (May 15, 2000). While Continental's petition
did not refer to its status as a hazardous waste generator, we
accept counsel's representation at oral argument that the
company also generates hazardous waste, and therefore is not
bringing this claim solely in its capacity as a hazardous waste
combustor. Accordingly, Continental has standing.
We decline to consider Continental's argument that EPA
should have conducted independent RFA analyses for each
class of HWCs. Continental's opening brief contains only a
single conclusory sentence stating this point, and its reply
brief does nothing to expand on the subject. A litigant does
not properly raise an issue by addressing it in a "cursory
fashion" with only "bare-bones arguments." Wash. Legal
Clinic for the Homeless v. Barry, 197 F.3d 32, 39 (D.C. Cir.
1997); Terry v. Reno, 101 F.3d 1412, 1415 (D.C. Cir. 1996);
Carducci v. Regan, 714 F.2d 171, 177 (D.C. Cir. 1983). Even
if the briefing were sufficient to raise this issue, it certainly is
not persuasive enough to carry Continental's burden of show-
ing that the agency's analysis was arbitrary and capricious.
As to Continental's second claim regarding generators of
hazardous waste, this court has consistently rejected the
contention that the RFA applies to small businesses indirectly
affected by the regulation of other entities. Mich. v. EPA,
213 F.3d 663, 688-89 (D.C. Cir. 2000); Motor & Equip. Mfrs.
Ass'n v. Nichols, 142 F.3d 449, 467 (D.C. Cir. 1998); Mid-Tex
Elec. Coop. v. FERC, 773 F.2d 327, 342 (D.C. Cir. 1985).
EPA's rule regulates hazardous waste combustors, not waste
generators. We explained in Mid-Tex that the language of
the statute limits its application to the "small entities which
will be subject to the proposed regulation"--that is, those
"small entities to which the proposed rule will apply." Mid-
Tex Elec. Coop., 773 F.2d at 342 (quoting 5 U.S.C. s 603(b)).
Congress "did not intend to require that every agency consid-
er every indirect effect that any regulation might have on
small businesses in any stratum of the national economy."
Id. at 343.
Continental acknowledges these precedents, but seeks to
distinguish this case on the basis that EPA actually intended
to affect the conduct of hazardous waste generators by rais-
ing the cost of incineration. This increase in cost would
create an economic incentive to minimize waste production.
As evidence, Continental cites the portion of the preamble to
the rule which states that the rule "fulfills our 1993 and 1994
public commitments to upgrade emissions standards for
HWCs. These commitments are the centerpiece of our Haz-
ardous Waste Minimization and Combustion Strategy." 64
Fed. Reg. at 52,832. Continental also refers us to EPA's
statement that "[a]s today's rule is implemented, the costs of
burning hazardous waste will increase, resulting in market
incentives for greater waste minimization." 64 Fed. Reg. at
53,021.
Contrary to what Continental supposes, application of the
RFA does turn on whether particular entities are the "tar-
gets" of a given rule. The statute requires that the agency
conduct the relevant analysis or certify "no impact" for those
small businesses that are "subject to" the regulation, that is,
those to which the regulation "will apply." Mid-Tex Elec.
Coop., 773 F.2d at 342; 5 U.S.C. s 605(b)(3). EPA's rule
applies, by its terms, only to HWCs. The rule will doubtless
have economic impacts in many sectors of the economy. But
to require an agency to assess the impact on all of the
nation's small businesses possibly affected by a rule would be
to convert every rulemaking process into a massive exercise
in economic modeling, an approach we have already rejected.
See Mid-Tex Elec. Coop., 773 F.2d at 343.
VI
The Environmental Technology Council, a trade association
representing firms involved in disposal of hazardous wastes,
petitions for review of 40 C.F.R. ss 63.1206(b)(9) & (10).
These provisions create alternative emission standards for
cement kilns and lightweight aggregate kilns. EPA ex-
pressed concern that some sources might not be able to meet
some of the MACT standards because of raw material contri-
bution to emissions, and therefore enacted the alternative
standards for SVMs, LVMs, chlorine and mercury. Id.; see
also 64 Fed. Reg. at 52,962-67; Revised Standards for Haz-
ardous Waste Combustors, 61 Fed. Reg. 17,358, 17,395 &
17,405 (Apr. 19, 1996); Final Response to Comments to the
Proposed HWC MACT Standards, Volume II: Compliance:
Equivalency Determination and Alternate Standards, at 7
(July 1999). The Council contends that these provisions vio-
late the language of s 7412, and are arbitrary and capricious.
We refuse to consider these contentions because the Council
lacks prudential standing.
The Council rests its claims of constitutional and prudential
standing on the ground that its members will suffer "econom-
ic and competitive injury, most significantly diminished value
of capital investment, if competing facilities are excused from
the MACT standards and thereby avoid the substantial com-
pliance costs." Envtl. Tech. Council's Opening Br. at 7.
According to the Council, its members have already made
substantial investments in various pollution control technolo-
gies and constitute the "best performing sources" to which
the CAA refers in s 7412(d). It alleges that its interests in
ensuring that other HWCs comply with the MACT standards
(which they concede are purely economic), are congruent with
the interests protected by the statute, and that it is therefore
a "suitable challenger" within the zone of interests of the
CAA.
The Council appears to have constitutional standing. It
claims that there are numerous costs associated with meeting
the MACT standards, and that EPA's creation of an alterna-
tive standard will save some competitors from those costs.1
Basic economics indicates that a competitor whose costs are
lower will be able to provide services at lower cost--and one
can reasonably expect this to result in lost business to the
Council's members. Accordingly, we think the Council has
met its constitutional obligation to show injury, causation, and
redressability. Lujan v. Defenders of Wildlife, 504 U.S. 555,
560-62 (1992).
The problem for the Council is that we have previously
rejected prudential standing in two nearly identical cases in
which industry groups claimed to be suitable challengers to
regulations directed at competitors. Hazardous Waste
Treatment Council v. EPA, 885 F.2d 918 (D.C. Cir. 1989)
(HWTC IV); Hazardous Waste Treatment Council v. EPA,
861 F.2d 277 (D.C. Cir. 1988) (HWTC II). To demonstrate
prudential standing, ordinarily a party must show that the
interest it seeks to protect "is arguably within the zone of
__________
1 At oral argument the court pointed out to counsel that the
alternative standards require a facility seeking the exemption to
demonstrate that "even though [it uses] MACT control" technology,
it still cannot meet the standard. 64 Fed. Reg. at 52,965-66. In
light of this, the court inquired what injury the exception might
inflict on the Council's members. The attorney for the Council
explained that the "best performing sources" rely on techniques
other than just technological aids to reduce pollution, and that these
techniques cost money to implement. EPA did not contest this
representation.
interests to be protected or regulated by the statute ... in
question." Ass'n of Data Processing Serv. Orgs. v. Camp,
397 U.S. 150, 153 (1970). Under this "zone of interests" test,
the "essential inquiry is whether Congress 'intended for [a
particular] class [of plaintiffs] to be relied upon to challenge
agency disregard of the law.' " Clarke v. Securities Indus.
Ass'n, 479 U.S. 388, 399 (1987) (quoting Block v. Cmty.
Nutrition Inst., 467 U.S. 340, 347 (1984)). While the "zone of
interests" test is not meant to be "especially demanding," it
will deny standing to one claiming to be a "suitable challeng-
er" when "plaintiff's interests are so marginally related to or
inconsistent with the purposes implicit in the statute that it
cannot reasonably be assumed that Congress intended to
permit the suit." Id.
In HWTC II we considered the claim of an industry group
similar to the Council that challenged EPA regulations under
RCRA and sought tighter controls on competitors.2 861 F.2d
at 282. Petitioner there claimed prudential standing because
"tightening of environmental standards will generally foster
not only a cleaner environment but also expand the member
companies' profits, as it will expand the market for their
services." Id. Petitioner argued that its interests were "in
sync" with those served by RCRA. We rejected this argu-
ment. The "consumers of the environmental purity afforded
by RCRA seem highly suitable champions of enforcement."
Id. at 284. Petitioner's interest was not in environmental
purity, but in increasing the regulatory burden on its compet-
itors. To hold that this satisfied prudential standing would
be to create "a considerable potential for judicial intervention
that would distort the regulatory process." Id. at 285. We
followed the same analysis in HWTC IV. 885 F.2d at 922-26.
The case before us is identical to HWTC II and IV, except
that the relevant statute is the CAA, not RCRA. The
__________
2 EPA contends that the Council is actually the same organization
as the HWTC, with a different name. The Council does not contest
this representation. Whether the two organizations are the same
does not matter here, however, as it is clear that their positions and
arguments are identical.
Council thinks this makes all the difference--that by adopting
a technology-based approach to emissions standards, Con-
gress aligned the interests of competitors and environmental-
ists in such a way as to bring the former into the zone of
interests. We disagree. The Council has identified nothing
to indicate that Congress' shift to a technology-based ap-
proach was anything more than a determination that this
would provide a more workable basis for promulgating stan-
dards. The statute's language indicates that, contrary to the
Council's contention, Congress' "evident purpose" was not to
"compel[ ] those sources with less-than-best pollution control
to invest in upgraded equipment." Neither the statute nor
the rules actually require HWCs to use the same methods of
emission control used by the best performing sources; they
must only meet the standards of those that do. See 42 U.S.C.
s 7412(d)(2); 64 Fed. Reg. at 52,963 n.255. As in the HWTC
cases, the Council's interest lies only in increasing the regula-
tory burden on others. See HWTC IV, 885 F.2d at 924-25;
HWTC II, 861 F.2d at 285. The Council therefore lacks
prudential standing.
VII
We remand the HWC floors to EPA for further proceed-
ings consistent with this opinion. In so doing, we emphasize
that we do not expect the impossible of the Agency. Floors
need not be perfect mirrors of the best performers' emissions.
But whether EPA chooses end-of-stack technology or feed-
rate as the MACT control, or abandons the MACT approach
altogether, CAA section 7412(d)(3), as interpreted by this
court in Sierra Club and National Lime II, requires that
floors reflect a reasonable estimate of the emissions
"achieved" in practice by the best-performing sources. See
Nat'l Lime II, 233 F.3d at 632.
Because EPA will have to set new floors, we need not
address the Sierra Club's additional arguments that in decid-
ing whether to set beyond-the-floor standards pursuant to
CAA section 7412(d)(2), EPA failed to consider several non-
air quality health and environmental impacts that commen-
ters claimed result from HWC emissions, as well as whether
stricter standards based on additional controls would be
achievable. See id. at 634 (declining to address beyond-the-
floor arguments regarding two HAPs because the floors for
those HAPs were being remanded). Nor, for the same
reason, need we consider industry petitioners' challenges to
specific standards.
Finally, the Sierra Club requests that we leave the current
regulations in place during remand in order to "avoid serious
adverse implications for public health and the environment
that would result from vacating the regulations (and thus
allowing hazardous waste combustors to emit even more
HAPs than allowed by the regulation[s] ... )." Sierra Club's
Opening Br. at 36. Though we granted similar requests in
Sierra Club, 167 F.3d at 664, and National Lime II, 233 F.3d
at 635, we think this case is different: in Sierra Club, there
were no industry petitioners, and in National Lime II, we
considered and rejected industry claims. Here, in contrast,
we have chosen not to reach the bulk of industry petitioners'
claims, and leaving the regulations in place during remand
would ignore petitioners' potentially meritorious challenges.
For example, industry petitioners may be correct that EPA
should have exempted HWCs from regulatory limits during
periods of startup, shutdown, and malfunction, permitting
sources to return to compliance by following the steps of a
startup, shutdown, and malfunction plan filed with the Agen-
cy. We have similar doubts about EPA's decision to require
sources to comply with standards even during openings of
emergency safety valves caused by events beyond the
sources' control. It is also possible that some of the emission
standards themselves would not have withstood arbitrary and
capricious analysis: when setting the beyond-the-floor stan-
dard for dioxin emissions from lightweight aggregate kilns,
EPA may have relied inappropriately on data from cement
kilns (a method it had previously rejected) to demonstrate
that the standard was achievable; in setting the beyond-the-
floor standard for semi-volatile metal emissions from cement
kilns, EPA may have exceeded its statutory mandate by
relying on policy objectives other than those enumerated in
section 7412(d).
In light of these circumstances, we think the better course
of action is to vacate the challenged regulations. Because
this decision leaves EPA without standards regulating HWC
emissions, EPA (or any of the parties to this proceeding) may
file a motion to delay issuance of the mandate to request
either that the current standards remain in place or that EPA
be allowed reasonable time to develop interim standards. See
Columbia Falls, 139 F.3d at 924 ("If EPA wishes to promul-
gate an interim treatment standard, the Agency may file a
motion in this court to delay issuance of this mandate in order
to allow it a reasonable time to develop such a standard.").
So ordered.