Court Opinion

ID: 185467
Source: CourtListenerOpinion
Date Created: 2011-02-05 02:32:27+00
Date Added: 2024-06-11T17:26:16.178479
License: Public Domain

255 F.3d 855 (D.C. Cir. 2001)
Cement Kiln Recycling Coalition, et al., Petitionersv.Environmental Protection Agency and Christine Todd Whitman, Administrator, RespondentsDow Chemical Company, et al., IntervenorsNos. 99-1457, 99-1477, 99-1480, 99-1483, 99-1485, 99-1486, 99-1490 to 99-1498.United States Court of Appeals FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued April 24, 2001Decided July 24, 2001

No. 99-1457
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, Attorney, 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 Environmental Technology Council.
Before:  Randolph, Rogers and Tatel, Circuit Judges.
Opinion for the Court filed Per Curiam.*

Per Curiam:

1
In this case, industry and environmental  petitioners challenge EPA air pollution standards for hazardous 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.

2
* Until 1990, the Clean Air Act ("CAA"), 42 U.S.C. §§ 74017671q, 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.  7412(b)(1)(B) (1990);  see also H.R. Rep. No. 101-490, at  151, 322 (1990).  To address problems with the implementation of risk-based regulation, Congress amended the Act in  1990 to require EPA to set the most stringent standards  achievable, 42 U.S.C. 7412(d)(2), that is, standards "based  on the maximum reduction in emissions which can be  achieved by application of [the] best available control technology."  S. Rep. No. 101-228, at 133 (1989).

3
The 1990 amendments included the provision at issue in  this case--42 U.S.C. 7412(d)--which directs EPA to set  standards limiting emissions of listed hazardous air pollutants  ("HAPs"), id. §§ 7412(b), (c)(1)-(2), from major stationary  sources.  Section 7412(d)(2) provides that:

4
Emission standards ... shall require the maximum degree of reduction in emissions of the hazardous air pollutants subject to this section ... that the Administrator, taking into consideration the cost of achieving such emission reduction, and any non-air quality health and environmental impacts and energy requirements, determines is achievable for new or existing sources....

5
Supplementing this general guidance, Congress imposed minimum 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. 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. 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 Administrator 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 determines whether stricter standards, known as "beyond-thefloor" limits, are achievable in light of the factors listed in  section 7412(d)(2).  233 F.3d at 629.

6
Hazardous waste combustors ("HWCs"), the focus of this  case, are also subject to regulation under the Resource Conservation and Recovery Act ("RCRA"), 42 U.S.C. §§ 69016992k, 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. 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. 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).

7
In 1999, acting pursuant to CAA section 7412(d) and following notice and comment, EPA issued standards limiting emissions 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.

8
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;  exposure can cause effects such as cancer, neurological and organ  damage, and impaired child development.  See id. at 53,002-03.

9
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 achievable control technology) floors."  After assembling a database  of sources and their emission levels recorded primarily during  RCRA compliance tests, the Agency went through the following 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-ofstack 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 methodology but chose as the MACT control the technology used  by the best-performing source for which it had information.

10
After setting forty-nine floors, EPA considered, as required  by section 7412(d)(2), whether stricter limits--"beyond-thefloor" standards--would be achievable.  Taking into account  cost, energy requirements, and certain non-air quality health  and environmental impacts, EPA ultimately set five beyondthe-floor standards.

11
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 determinations, 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 section 7412(d)(3)(A) by basing existing-source floors on actual  emissions data rather than on existing regulatory requirements, such as RCRA permit limits.  Industry petitioners  also challenge as arbitrary and capricious many individual  emission standards, as well as several monitoring and implementation regulations.  One industry petitioner, Continental  Cement, argues that EPA violated the Regulatory Flexibility  Act, 5 U.S.C. §§ 601-612.  Another petitioner, the Environmental Technology Council, challenges EPA's adoption of  procedures that permit sources to petition the Agency for  alternative requirements if they cannot meet MACT standards due to raw material contributions to emissions.  See 40  C.F.R. §§ 63.1206(b)(9) & (10).

II

12
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 information)...."  42 U.S.C. 7412(d)(3)(A).  Focusing on the  phrase "emission limitation," petitioners point out that CAA  section 7602(k) defines that term as "a requirement established by the State or the Administrator which limits the  quantity, rate, or concentration of emissions of air pollutants...."  Id. 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 requirement limiting emissions of a pollutant achieved in  practice by the best performing 12 percent of the existing  sources."  Indus. Petitioners' Opening Br. at 8.

13
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.  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 review.").  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 responded 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 practice...."  Final Response to Comments to the Proposed  HWC MACT Standards, Vol. I:  Standards ("1 Final Response 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 considered 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 consider RCRA permit limitations in establishing floors," Respondent'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").

14
In considering the extent to which a statutory interpretation must have been presented to an agency before a petitioner can raise it here, we have said that:

15
[w]hile there are surely limits on the level of congruity required between a party's arguments before an administrative 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 agency's interpretation of its governing statute are first raised in the administrative forum.

16
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

17
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 actually "achieve[ ]," demonstrates that "Congress was well aware  of the difference between what EPA believes to be 'achievable' 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 discretion by enacting [section 7412]'s mandatory floor provisions in the 1990 Amendments."  Id. at 21-22.

18
Defending its achievability rationale, EPA argues that section 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 standard.  For this reason, EPA explains, it designed the MACT  approach to produce achievable standards.

19
We agree with the Sierra Club.  Though section 7412(d)(2)  does direct EPA to require the "maximum emission reduction" 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 statutory 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").

20
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.  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 percent 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 required 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 control 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).

21
We thus turn to EPA's alternative argument:  that the  MACT approach does in fact measure what the bestperforming sources actually achieve.  According to EPA,  Sierra Club requires standards to reflect "the worst reasonably 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.  Respondent'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 foreseeable circumstances.

22
The Sierra Club disagrees, arguing that EPA has failed to  abide by Sierra Club because the Agency has not demonstrated 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 questioning 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 technology[,].... 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 operators, 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.

23
Applying the principles set forth in Sierra Club and National Lime II, we again agree with the Sierra Club.  To  begin with, Sierra Club permits EPA to account for variability 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:

24
it became clear [at oral argument] that the Sierra Club believes that EPA's MACT approach would not accurately 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 lesspolluting fuels or purer raw materials.  Such plants would have predictably lower emissions than plants using MACT floor technology alone.

25
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.

26
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. §§ 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 scrubber, 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 performance.  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 fabrics ... have demonstrated levels below 0.0010 gr/dscf over  long term operation.").

27
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 observed 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 Agency's attention factors other than the MACT control.  One  commenter noted that:

28
[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, identifying the emissions rates associated with a particular type of control device indicates very little about the actual capability of that type of control device.

29
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 technology.  See id. at 53-55.

30
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.

31
The Agency argues that "there is no question as to the type  of control device each source uses."  Respondent's Br. at 3839.  But as the Sierra Club points out, this claim is nonresponsive:  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.

32
EPA next claims that even though the performance of the  MACT controls themselves vary, "effort[s] at further specification [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 declined 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 approach.  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 wideranging 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 emissions achieved by the best-performing sources.

33
Finally, we are unpersuaded by EPA's claim that to account 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 variability in the performance of emission controls such as baghouses, 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 experienced 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 accounting for operational variability fails to demonstrate the relevant relationship.  Some of the Agency's citations to the  record merely contain assertions that "[the] approach ...  fully accounts for normal process variability."  1 Final Response to Comments:  MACT Floor Approaches, at 59;  see  also 64 Fed. Reg. at 52,923 (noting that HWCs are particularly 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 bestperforming sources ever experience a wide range of variability 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 Standards, at 4-7 (July 1999) (explaining the operating parameters of various control technologies).  Indeed, throughout the  rulemaking, EPA defended its reliance on the worstperforming 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).

34
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 performers.  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 approach, however, concluding that "it could not be demonstrated 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 emissions achieved by the worst-performing sources and the variability 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 undermines 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 under 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?

35
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 worstperforming 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 evidence--not mere assertions--that MACT technology significantly 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

36
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 conditions by

37
spiking metals and chlorine in the waste feeddetuning 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 ...types of wastes, combustion system parameters, and emission control parameters.

38
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.

39
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,

40
merely confirms that standards based on the data reflect the most adverse conditions that can reasonably be expected to recur....  Because these test conditions are specifically designed to help account for operating variability, 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.

41
Respondent's Br. at 33 (internal quotation omitted).  According to EPA, because the statute permits it to use available  information to identify the best-performing sources, and because RCRA data are available information, it reasonably  relied on RCRA test results.

42
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.  7412(d)(3)(A) (emphasis added).  We think it not at all  unreasonable for the Agency to read this language as permitting 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 datagathering 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 quotation 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 circumstances."  Id. at 665.  In other words, the Sierra Club  has failed to demonstrate that EPA's model "bears no rational relationship to the reality it purports to represent," Columbia Falls Aluminum Co. v. EPA, 139 F.3d 914, 923 (D.C. Cir.  1998) (internal quotation omitted).

V

43
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.  §§ 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).

44
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. §§ 605, 603,  604.  Small entities include small businesses, small organizations, and small governmental jurisdictions.  Id. 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 economic impact [of the rule] on small entities."  Id. 604(a)  (final regulatory flexibility analysis);  see also id. §§ 603(b) &  (c) (initial regulatory flexibility analysis).

45
This procedure is intended to evoke commentary from  small businesses about the effect of the rule on their activities, 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 substantial number of small entities."  Id. 605(b).  EPA relied  on the 605(b) exception.

46
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 hazardous 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 generators 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 businesses.  Id.

47
Continental claims that EPA should have considered each  category of HWCs separately in conducting its "direct impact" 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.

48
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.

49
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 showing that the agency's analysis was arbitrary and capricious.

50
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."  MidTex Elec. Coop., 773 F.2d at 342 (quoting 5 U.S.C. 603(b)). Congress "did not intend to require that every agency consider every indirect effect that any regulation might have on  small businesses in any stratum of the national economy." Id. at 343.

51
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 raising 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 Hazardous 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.

52
Contrary to what Continental supposes, application of the  RFA does turn on whether particular entities are the "targets" 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. 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

53
The Environmental Technology Council, a trade association  representing firms involved in disposal of hazardous wastes,  petitions for review of 40 C.F.R. §§ 63.1206(b)(9) & (10). These provisions create alternative emission standards for  cement kilns and lightweight aggregate kilns.  EPA expressed concern that some sources might not be able to meet  some of the MACT standards because of raw material contribution 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 Hazardous 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 violate the language of 7412, and are arbitrary and capricious. We refuse to consider these contentions because the Council  lacks prudential standing.

54
The Council rests its claims of constitutional and prudential  standing on the ground that its members will suffer "economic and competitive injury, most significantly diminished value  of capital investment, if competing facilities are excused from  the MACT standards and thereby avoid the substantial compliance costs."  Envtl. Tech. Council's Opening Br. at 7. According to the Council, its members have already made  substantial investments in various pollution control technologies and constitute the "best performing sources" to which  the CAA refers in 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.

55
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 alternative 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).

56
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  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 challenger" 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.

57
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 argument.  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 competitors.  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.

58
The case before us is identical to HWTC II and IV, except  that the relevant statute is the CAA, not RCRA.  The  Council thinks this makes all the difference--that by adopting  a technology-based approach to emissions standards, Congress aligned the interests of competitors and environmentalists 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 approach was anything more than a determination that this  would provide a more workable basis for promulgating standards.  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.  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 regulatory 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

59
We remand the HWC floors to EPA for further proceedings 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 feedrate 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.

60
Because EPA will have to set new floors, we need not  address the Sierra Club's additional arguments that in deciding whether to set beyond-the-floor standards pursuant to  CAA section 7412(d)(2), EPA failed to consider several nonair quality health and environmental impacts that commenters 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-thefloor 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.

61
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 Agency.  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 standard 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-thefloor 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).

62
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 promulgate 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.").

63
So ordered.

Notes:

*
 Judge Tatel wrote Parts I, II, III, IV, and VII;  Judge Randolph wrote Parts V and VI.

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.

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.