 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued November 19, 2014             Decided May 29, 2015

                       No. 12-1260

            MEXICHEM SPECIALTY RESINS, INC.,
                     PETITIONER

                             v.

     ENVIRONMENTAL PROTECTION AGENCY AND GINA
                    MCCARTHY,
                   RESPONDENTS

              AIR ALLIANCE HOUSTON, ET AL.,
                      INTERVENORS


       Consolidated with 12-1265, 12-1266, 12-1267


          On Petitions for Review of Final Actions
   of the United States Environmental Protection Agency


     Douglas J. Behr and Jean-Cyril Walker argued the causes
for Industry Petitioners. With them on the briefs were David
M. Friedland, Kristen H. Gladd, Marc D. Machlin, and
Christopher D. Jensen. Eric P. Gotting and Peter L. de la
Cruz entered appearances.

    Angeline Purdy, Attorney, U.S. Department of Justice,
argued the cause for respondent. With her on the brief were
                              2
Sam Hirsch, Acting Assistant Attorney General, and Mark
Kataoka, Counsel, U.S. Environmental Protection Agency.

     Emma C. Cheuse argued the cause for respondent-
intervenors. With her on the brief was James S. Pew.

    Before: ROGERS, KAVANAUGH and PILLARD, Circuit
Judges.

    Opinion for the Court filed by Circuit Judge PILLARD.

   Opinion dissenting in part filed by Circuit Judge
KAVANAUGH.

    PILLARD, Circuit Judge: This case concerns the
production of polyvinyl chloride (PVC), one of the world’s
most common and versatile plastics, used in everything from
water pipes to credit cards. As is true of the making of so
many good things, however, the less one knows, the better
one sleeps. PVC production results in the emission of more
than a dozen known or suspected carcinogens and other
hazardous air pollutants, a miasma that includes the known
carcinogens 1,3-butadiene, benzene, and vinyl chloride. See
Proposed PVC Rule, 76 Fed. Reg. 29,528, 29,532 (May 20,
2011). Congress has charged the Environmental Protection
Agency with the difficult task of protecting the health of the
American public by ensuring that industry reduce to the
greatest extent it can emissions into the atmosphere of
carcinogens and similarly dangerous chemicals.

     In 2012, EPA promulgated a Rule setting first-time-ever
limits on the emission of most hazardous air pollutants from
PVC production. Petitioners, PVC manufacturers, challenge
the Rule. They contend that many of the Rule’s emissions
limits should be vacated on the grounds that EPA did not
                                 3
follow required rulemaking procedures, used faulty data in
setting some of the limits, and poorly designed certain aspects
of the regulation. They also ask the court to set aside some of
the Rule’s monitoring and compliance requirements.
Petitioners raised many of these objections for the first time in
petitions for reconsideration with EPA that are awaiting
resolution. The Clean Air Act therefore precludes the court
from reviewing them now, and we decline Petitioners’ request
that we stay EPA’s Rule pending the agency’s completion of
its reconsideration. As to those challenges to the Rule that are
ready for our review, we hold that EPA acted reasonably and
in accordance with the Clean Air Act. We therefore deny the
petitions.

                                 I.

     The Clean Air Act requires EPA to promulgate
regulations limiting the emission of hazardous air pollutants
from      “major      sources”     and     “area     sources.”
42 U.S.C. § 7412(d)(1). Those pollutants are specified on a
list of hazardous air pollutants Congress established in 1990
in an amendment to the Act.1 42 U.S.C. § 7412(b)(1); see
Nat’l Lime Ass’n v. EPA, 233 F.3d 625, 628-29, 633-34 (D.C.
Cir. 2000). For listed pollutants, EPA must set emissions
standards in two steps: First EPA sets a baseline, or “MACT
floor,” derived from data about the cleanest-performing
similar sources already in the market; and, second, EPA
investigates methods that may not already be in use to discern

1
 The difference between major sources and area sources is size: A
“major source” is a stationary source that has the potential to emit
10 tons per year of any single hazardous air pollutant or 25 tons per
year of any combination of hazardous air pollutants,
42 U.S.C. § 7412(a)(1); any smaller stationary source is an “area
source,” id. § 7412(a)(2).
                                 4
whether even more stringent, “beyond-the-floor” standards
are achievable to further reduce emissions.2              See
42 U.S.C. §§ 7412(d)(2), (d)(3); Nat’l Lime, 233 F.3d at 629,
634.

     The Rule under review establishes limits on hazardous air
pollutant emissions from major and area sources at various
points in the PVC production process. See PVC Rule, 77 Fed.
Reg. 22,848, 22,851-55 (Apr. 17, 2012); id. at 22,857-59
(summarizing major source emissions standards); id. at
22,862-63 (summarizing area source emissions standards).
The Rule limits the concentration of hazardous air pollutants
that may remain in PVC resins (the “stripped resins” limits),
the concentration of hazardous air pollutants that can be
present in exhaust vented into the atmosphere (the “process
vent” limits), and the concentration of hazardous air
pollutants that may be dissolved in wastewater (the “process
wastewater” limits). Proposed PVC Rule, 76 Fed. Reg. at
29,531-35; see also 40 C.F.R. § 63.12005. The Rule also
requires the installation of monitoring equipment and the
implementation of testing policies and workplace practices,
all of which are designed to ensure initial and continuous
compliance with EPA’s emissions limits. See PVC Rule, 77
Fed. Reg. at 22,859-62 (summarizing compliance
requirements).

     The Rule stems from Congress’s 1990 amendments to the
Clean Air Act. In those amendments, Congress (1) mandated
that EPA regulate over one hundred specified hazardous air

2
    “MACT” is short for “Maximum Achievable Control
Technology.” Nat’l Lime, 233 F.3d at 630. MACT floors are
“floors” because they represent the least stringent emissions limits
EPA may impose, “even though they in fact establish maximum
emission levels” for manufacturers. Id. at 629.
                              5
pollutants, Nat’l Lime, 233 F.3d at 633, and (2) required EPA
to review within ten years of the Act’s amendment all of its
preexisting emissions standards to ensure that they cover
listed pollutants. 42 U.S.C. § 7412(q)(1); see Mossville Envtl.
Action Now v. EPA, 370 F.3d 1232, 1236-37 (D.C. Cir. 2004).
As of 1990, EPA already had a longstanding regulation
limiting the emission of vinyl chloride, one of the hazardous
air pollutants from PVC sources. 41 Fed. Reg. 46,560 (Oct.
21, 1976). Congress’s amendments required EPA to revisit
its pre-1990 vinyl chloride emissions standard and expand it
to regulate all the newly listed hazardous air pollutants from
PVC sources.

      EPA got part of the way there. It promulgated a rule in
1992, the “HON Rule,” that regulated emissions from the
production of ethylene dichloride and vinyl chloride
monomer, two inputs to PVC production.3 Mossville, 370
F.3d at 1237. The HON Rule did not, however, regulate
emissions arising from the production of PVC itself. Id.
Because the HON Rule did not cover PVC production, EPA
still needed to undertake another rulemaking to comply with
Congress’s mandate that it revisit and expand its earlier vinyl
chloride regulation. Id. That second Rule is at issue here.

     EPA began development in 1998 of a version of the Rule
that it promulgated in 2002. See 67 Fed. Reg. 45,886, 45,889
(July 10, 2002). In that Rule, EPA readopted its pre-1990
limits for vinyl chloride emissions from PVC production,
determining that those limits were a good estimate of the
MACT floors for vinyl chloride. Mossville, 370 F.3d at 1237.
In a challenge to the 2002 rule’s lawfulness and rationality
3
  “HON” is short for “Hazardous Organic NESHAP.” See
Mossville, 370 F.3d at 1237. “NESHAP” is short for “National
Emission Standards for Hazardous Air Pollutants.” Id. at 1235.
                               6
under the Clean Air Act, we sustained EPA’s judgment. Id. at
1234, 1237, 1242. We found the Rule flawed in part,
however, for its failure to set limits on all of the remaining
hazardous air pollutants the Act requires EPA to regulate. Id.
at 1242-43. EPA argued that the same technologies that
remove vinyl chloride from PVC emissions—“stripping,
scrubbing, incineration”—reduce the emission of all
hazardous air pollutants to a similar degree and that the
emissions limit for vinyl chloride therefore could stand in as a
“surrogate” for setting individual limits on the emission of
other hazardous air pollutants. Id. at 1237. We found EPA’s
judgment on that point unsupported by the record and vacated
and remanded the Rule for further explanation and
reconsideration, as appropriate. Id. at 1243.

     In 2009, EPA began issuing information requests to PVC
manufacturers and otherwise gathering the data necessary to
set MACT floors for non-vinyl chloride hazardous air
pollutants from PVC production. EPA issued a proposed rule
in 2011 and accepted comments for a period of two and a half
months. See Proposed PVC Rule, 76 Fed. Reg. at 29,528; 76
Fed. Reg. 42,613 (July 19, 2011). After the close of the
public comment period, PVC manufacturers continued to
submit data to EPA, including data the manufacturers
recorded from sampling and testing independently of what
EPA’s data requests required. In response to some of that
new information, submitted after the comment period closed,
EPA revised its Rule. EPA promulgated the Rule in April
2012. See PVC Rule, 77 Fed. Reg. 22,848. Industry
Petitioners promptly petitioned EPA for reconsideration and
sought judicial review, arguing that EPA had given
Petitioners inadequate notice and opportunity to comment on
EPA’s post comment period revisions.             EPA granted
reconsideration on several of Petitioners’ claims.
                                 7
                                II.

     Petitioners challenge three aspects of EPA’s Rule. First,
Petitioners challenge the Rule’s limit on the concentration of
organic hazardous air pollutants in process wastewater from
existing major sources.         Petitioners argue that EPA
established that limit without providing adequate notice or
opportunity to comment. They also argue that the limit is not
a logical outgrowth of the proposed rule and that EPA based
the limit on data that was incorrect and incomplete.4


4
  On the eve of oral argument, EPA and Petitioners reached a
settlement on EPA’s Rule setting wastewater limits for area
sources. They filed a joint unopposed motion to sever their
challenge to that Rule and hold it in abeyance, which this court
granted. See Mexichem Specialty Resins, Inc. v. EPA, No. 12-1260
(D.C. Cir. Dec. 17, 2014) (order granting joint unopposed motion to
sever and hold in abeyance the challenge to the area source
wastewater limit).     The same emissions limit that governs
wastewater from area sources also governs new major sources.
That limit was based on a single data point that EPA acknowledges
to be erroneous. See Resp. Br. 21, 35; PVC Rule, 77 Fed. Reg. at
22,854, 22,863. Neither EPA nor Intervenors oppose vacatur of
that emissions limit. See Resp. Br. 35-36; Int. Br. 20, 33. The
parties did not, however, move to sever and hold in abeyance the
new major source wastewater emissions limit when they made their
motion with respect to the area source emissions limit.

  The court, however, is barred from vacating or staying the new
major source wastewater limit. Petitioners failed to preserve their
challenges to the wastewater emissions limits, including the new
major source wastewater limit, and EPA did not waive its
exhaustion defense. Petitioners were therefore required to show
irreparable harm from the existence of the new major source
wastewater limit to obtain a right to a stay or vacatur. Petitioners
                                 8
     Second, Petitioners challenge the Rule’s limits on
hazardous air pollutants emitted through process vents.
EPA’s proposed rule set limits applicable to all PVC process
vents. During the rulemaking, however, PVC manufacturers
notified EPA that some PVC manufacturers also discharge
exhaust generated by other (non-PVC) processes through
PVC process vents. See PVC Rule, 77 Fed. Reg. at 22,851.
In response, EPA created a hybrid category in the final
Rule—“PVC-combined” process vents—setting distinct
emissions limits for process vents that comingle fumes from
PVC and non-PVC sources. 40 C.F.R. § 63.12005; see PVC
Rule, 77 Fed. Reg. at 22,865, 22,869. Petitioners raise a spate
of objections to EPA’s process vent limits and its decision to
create the separate PVC-combined process vent category.
They argue that EPA established the PVC-combined process
vent limits without providing adequate notice or opportunity
to comment.       Petitioners claim they were denied an
opportunity to provide EPA with supplemental data they
believe is necessary to develop accurate PVC-combined
process vent limits. Petitioners also maintain that the PVC-
combined process vent emissions limits as applied to non-
PVC source emissions when they discharge through a
common vent with PVC source emissions unlawfully conflict
with the limits that already apply to the non-PVC sources.

have not, however, alleged or shown any harm arising from the
existence of the limit. Indeed, the record contains no evidence that
Petitioners have any plans to build new major sources. The Clean
Air Act therefore prevents the court from staying or vacating the
new major source wastewater limit.

  Because the limits for area sources have been severed and the
limits for new major sources are not properly before us, we limit
our discussion in the text to the challenge to the existing major
source limits.
                                 9
Petitioners further contend that EPA’s Rule irrationally fails
to subcategorize process vents on the basis of their emissions
control technology.

     Third and finally, Petitioners challenge some of the
Rule’s continuous compliance and monitoring provisions.
They argue that EPA’s regulations governing when
manufacturers may open “bypasses” and mandating the
installation of monitoring equipment on “pressure relief
devices” are arbitrary and capricious.5 Petitioners also
contend that regulations requiring that all bypasses be
equipped with devices that detect when they are opened are
“beyond-the-floor” MACT requirements that EPA unlawfully
imposed without engaging in cost-benefit analysis as required
by the Clean Air Act.

     We deny the petitions.        Petitioners did not raise
procedural or merits objections to the wastewater limit during
the notice and comment period. Petitioners also did not raise
procedural objections to the PVC-combined process limit
during the notice and comment period or challenge the

5
   Bypasses, as their names suggest, allow fumes to bypass
emissions controls and discharge directly into the atmosphere.
See 40 C.F.R. § 63.12005 (“Bypass means diverting a process vent
or closed vent system stream to the atmosphere such that it does not
first pass through an emission control device.”).

  Pressure relief devices are safety devices that, in the process of
relieving pressure, can release fumes directly into the atmosphere.
See 40 C.F.R. § 63.12005 (“Pressure relief device means a safety
device used to prevent operating pressures from exceeding the
maximum allowable working pressure of the process component.
A common pressure relief device is a spring-loaded pressure relief
valve.”).
                              10
rationality of the limit itself. The Clean Air Act prevents the
court from considering those objections because Petitioners
did not initially preserve them in the administrative process,
and EPA is still considering them in a pending
reconsideration proceeding. Given the absence of any
showing of a likelihood of irreparable harm, we also decline
to stay the effectiveness of the Rule until EPA completes its
reconsideration.

    We also reject each of Petitioners’ claims that we are
now able to review on its merits. EPA’s PVC-combined
process vent limits do not conflict with emissions limits
applicable to other sources that discharge through PVC-
combined process vents. EPA reasonably chose not to
subcategorize process vents on the basis of their control
technology.    EPA’s bypass and pressure relief device
regulations are reasonable compliance and monitoring
requirements, and Petitioners’ argument that the bypass-
detection regulation is a “beyond-the-floor” MACT
requirement lacks merit.

                             III.

     Several of Petitioners’ challenges to the Rule are barred
because they were not raised during the notice and comment
period. See 42 U.S.C. § 7607(d)(7)(B). Under the Clean Air
Act, “the only objections that may immediately be raised
upon judicial review are those that were raised during the
public comment period. Objections raised for the first time in
a petition for reconsideration must await EPA’s action on that
petition.” Util. Air Regulatory Grp. v. EPA (UARG), 744
F.3d 741, 747 (D.C. Cir. 2014). That bar extends both to
substantive and procedural challenges and applies even if the
objections could not have been raised during the comment
period. See 42 U.S.C. § 7607(d)(9)(D)(ii); UARG, 744 F.3d
                               11
at 747; Am. Petroleum Inst. v. Costle, 665 F.2d 1176, 1192
(D.C. Cir. 1981). That requirement serves the important
function of assuring that the agency has had an opportunity to
explicate and evaluate objections before we review them. See
generally Appalachian Power Co. v. EPA, 249 F.3d 1032,
1065 (D.C. Cir. 2001); Appalachian Power Co. v. EPA, 135
F.3d 791, 799 n.14 (D.C. Cir. 1998).

     Petitioners (1) did not raise their objections to the
adequacy of notice and comment during the notice and
comment period, (2) did not object that the final rule was not
a logical outgrowth of the proposed rule, (3) did not object to
the reasonableness of the PVC-combined process vent
emissions limits, and (4) did not object to the wastewater
limits. See Pet. Br. at 37, 48 (conceding failure to raise the
foregoing objections during the notice and comment period).
Those claims are therefore barred.

     Petitioners assert that the court should reach the merits of
their challenges to the Rule despite their failure to raise them
during the notice and comment period. The Clean Air Act’s
otherwise categorical bar on judicial review of objections first
raised in a petition for reconsideration may be excused only in
limited circumstances. Our precedents recognize certain
narrow exceptions to the exhaustion requirement, including
where the agency completes reconsideration but refuses to
acknowledge that it has done so, or where it unreasonably
delays the completion of reconsideration. See Sierra Club v.
Thomas, 828 F.2d 783, 792-96 (D.C. Cir. 1987); see generally
Randolph-Sheppard Vendors of Am. v. Weinberger, 795 F.2d
90, 104-09 (D.C. Cir. 1986).6

6
  Congress has partly abrogated Sierra Club v. Thomas, but its
analytical framework for determining whether EPA’s delay was
                                 12
      Petitioners suggest that EPA has functionally denied
their petitions for reconsideration. EPA granted the petitions
for reconsideration in September 2012 and does not anticipate
completing its review of those petitions until April 2016.
Petitioners also cite EPA’s data collection demands during the
reconsideration proceeding. EPA has issued several requests
for new data from PVC manufacturers, and EPA anticipates
opening a new notice and comment period on its proposed
modifications to the Rule before completing reconsideration.
According to Petitioners, EPA’s slow pace and ambitious data


unreasonable remains applicable to whether Petitioners may be
excused for their failure to exhaust their administrative remedies.
Thomas addressed the circumstances in which courts may compel
EPA to take action under the Clean Air Act, and, in that context,
held that this court had exclusive jurisdiction over claims to compel
agency action “unreasonably delayed.” Thomas, 828 F.2d at 792-
96. Congress in the 1990 Amendments to the Clean Air Act
abrogated Thomas’s jurisdictional holding and shifted to the district
court the power to compel EPA to act. See Clean Air Act
Amendments, Pub. L. No. 101-549, § 707(f), 104 Stat. 2399, 2683
(1990); see also 42 U.S.C. § 7604(a) (explaining that “the district
courts of the United States shall have jurisdiction to compel . . .
agency action unreasonably delayed”); S. Rep. No. 101-228, at 374
(1989). Those Amendments do not affect our jurisdiction here,
however, nor the aspect of Thomas on which we rely. This is not a
case seeking to compel EPA to take action, but a challenge to
existing EPA PVC emissions rules.             Petitioners raise their
unreasonable-delay allegation in an effort to rebut EPA’s
contention that Petitioners must await completion of EPA’s
pending reconsideration of the challenged Rule. When it amended
the Clean Air Act, Congress anticipated this very type of case,
“where a complaint about agency inaction is ‘embedded’ in a
challenge to agency action,” and did not withdraw our jurisdiction.
See S. Rep. No. 101-228, at 374 (citing Ind. & Mich. Electric Co. v.
EPA, 733 F. 2d 489, 490 (7th Cir. 1984)).
                              13
collection effort show it is not reconsidering the Rule but has
embarked on a new rulemaking in the guise of
reconsideration.

     EPA counters that the Clean Air Act requires EPA to
afford on reconsideration “the same procedural rights as
would have been afforded” at the time of the original
rulemaking, 42 U.S.C. § 7607(d)(7)(B), and that, in this case,
affording the parties those “same procedural rights” requires
additional data collection and new notice and opportunity for
comment. The agency is actively gathering additional data to
inform its action on reconsideration, anticipates holding open
a new notice and comment period, and predicts that it will
complete reconsideration by a date certain (April 2016).
There is thus neither a functional denial nor any suggestion in
this record that the Agency has finished reconsideration but
refused to acknowledge it.

     Petitioners also have failed to make the requisite showing
that EPA has engaged in unreasonable delay. To establish a
claim of unreasonable delay, petitioners must show that they
have “a right the denial of which we would have jurisdiction
to review upon final agency action but the integrity of which
might be irreversibly compromised by the time such review
would occur.” Thomas, 828 F.2d at 796. To qualify as
unreasonable, the agency’s delay would have to be “so
egregious as to warrant mandamus.” Id. at 797 (internal
quotation marks omitted). We have identified two avenues to
establishing an unreasonable delay claim: (1) showing that an
agency violated a statutory “right to timely decisionmaking”
implicit in the agency’s regulatory scheme, or (2) showing
that some other interest—financial, aesthetic, or related to
human health and welfare, for example—“will be irreparably
harmed through delay.” Id. at 796-97.
                              14
     Petitioners have failed to establish that EPA has deprived
them of a statutory right to timely decisionmaking. In
evaluating such a claim, we will (a) determine “whether
Congress has imposed any applicable deadlines,” “exhorted
swift deliberation concerning the matter,” or otherwise
“implicitly contemplate[d] timely final action;” (b) determine
“whether interests other than that of timely decisionmaking
will be prejudiced by delay;” and (c) determine “whether an
order expediting the proceedings will adversely affect the
agency in addressing matters of a competing or higher
priority.” Id. at 797. In assessing those factors, we are
mindful that, “[a]bsent a precise statutory timetable or other
factors counseling expeditious action, an agency’s control
over the timetable” of its proceedings “is entitled to
considerable deference,” id. (alteration in original) (internal
quotation marks omitted) (quoting Sierra Club v. Gorsuch,
715 F.2d 653, 658 (D.C. Cir. 1983)), and that “[e]ven where a
statutory timetable exists, noncompliance with it has
sometimes been excused as long as the agency has acted
rationally and in good faith,” Gorsuch, 715 F.2d at 658 n.35.

    The text and structure of the Act suggest that judgments
about the permissible duration of a Clean Air Act
reconsideration proceeding are fact bound and case specific.
The Clean Air Act does not specify limits on the permissible
duration of a reconsideration proceeding, and its provisions
generally grant the agency broad discretion to correct its own
mistakes before its rules are subjected to judicial review. See
42 U.S.C. §§ 7607(d)(7)(B), (d)(8).

    EPA’s forecasted duration of the reconsideration of the
wastewater limit and the PVC-combined process vent limit is
reasonably proportionate to the gravity and complexity of the
rulemaking. EPA has attempted to promulgate a PVC Rule
multiple times, and, each time, the attempt has taken several
                               15
years. EPA’s first attempt began data collection in 1998, and
the Rule issued in 2002. See 67 Fed. Reg. 45,886, 45,889
(July 10, 2002). This rulemaking began data collection in
2009 for a Rule that issued in 2012. See PVC Rule, 77 Fed.
Reg. at 22,852, 22,854. The scope of EPA’s reconsideration
in this case is proportional to the scope of the alleged
shortcomings in the 2012 rulemaking, and EPA estimates that
its current reconsideration proceeding will take about four
years, a duration commensurate with that of EPA’s prior
efforts to set emissions limits for PVC production.

     Petitioners also have failed to establish unreasonable
delay in completing reconsideration through the second route
our cases have identified: they have not shown that their
interests (in this case, financial) will be irreparably harmed if
the court awaits the outcome of EPA’s reconsideration
proceeding. See Thomas, 828 F.2d at 794-96; Randolph-
Sheppard Vendors, 795 F.2d at 107. As we have previously
explained in the cognate context of preliminary injunctions,
“[t]his court has set a high standard for irreparable injury.”
Chaplaincy of Full Gospel Churches v. England, 454 F.3d
290, 297 (D.C. Cir. 2006). Such injury must be “both certain
and great,” “actual and not theoretical,” “beyond
remediation,” and “of such imminence that there is a clear and
present need for equitable relief to prevent irreparable harm.”
Id. (internal quotation marks and citations omitted). Where
the injuries alleged are purely financial or economic, the
barrier to proving irreparable injury is higher still, for it is
“well settled that economic loss does not, in and of itself,
constitute irreparable harm.” Wisconsin Gas Co. v. FERC,
758 F.2d 669, 674 (D.C. Cir. 1985). Financial injury is only
irreparable where no “adequate compensatory or other
corrective relief will be available at a later date, in the
ordinary course of litigation.” Id.
                              16
     Petitioners have failed to show any specific, identifiable
cost they will incur because of the Rule’s emissions limits.
They acknowledged at oral argument that the record contains
no evidence of their cost of compliance, and they did not then
articulate any. See Oral Arg. Rec. at 72:55-75:26. For its
part, EPA has estimated that “the overall economic impact of
this final rule on the affected industries and their consumers
should be low,” amounting to approximately 0.7 percent of
PVC manufacturers’ revenues. PVC Rule, 77 Fed. Reg. at
22,900. EPA has also estimated that much of the cost of
meeting the new emissions standards will arise from verifying
compliance with the standard (measuring hazardous air
pollutant concentrations from process vents, for example), not
purchasing new control technology. See id. at 22,899-900.
Because costs of measuring emissions in order to monitor
compliance must be incurred under any emissions limit, they
are not specific to the emissions limits’ asserted irrationality
and thus not a source of prejudice arising from delay as such.

     Petitioners also have failed to establish that EPA’s post-
reconsideration emissions limits will differ materially from
the current limits.      That showing matters because, if
Petitioners will have to make the same investments and incur
the same costs to comply with EPA’s ultimate Rule as they
have to make under the current Rule, then any delay in
shifting from the current limits to (presumptively materially
equivalent) final ones is harmless. The court’s assessment of
the post-reconsideration rule’s likely modest impact on
existing emissions limits shows that delay in replacing EPA’s
current emissions limits is in fact likely to be harmless.

     In particular, with respect to the existing major source
wastewater limit, Petitioners have failed to show any
likelihood that the limit will materially change. Petitioners
argue the court should vacate EPA’s limit because EPA relied
                               17
on a faulty data point in setting the limit. But because EPA
set the limit through a methodology designed to protect
against variability of data, the distorting effect of a single,
erroneous data point was minimized; omitting the faulty data
point would make the wastewater limit 112 parts per million,
rather than 110 parts per million.7 See J.A. 317-18, 326-28.
Given that minimal difference, it is probable that Petitioners
would have incurred the same costs to comply with either
limit.

     That conclusion is bolstered by Petitioners’ own
evidence. Petitioners asserted by post-argument letter to this
court that their claim of irreparable harm from the Rule’s
wastewater limit is substantiated by a document they
submitted to EPA in the ongoing reconsideration proceeding
measuring emissions from selected PVC production facilities.
See Letter from Counsel to Petitioners to the Panel (Nov. 21,
2014). The document (assuming its accuracy) cuts against
Petitioners’ position, however, for it reveals that Petitioners’
plants would be unable to comply even with a 1000 parts per
million wastewater limit, a limit ten times greater than the 110
parts per million limit in the current Rule. See Letter from
Richard Krock, Vinyl Institute to Andrea Siefers, USEPA,
EPA-HQ-OAR-2002-0037-0561, at 28 (Aug. 16, 2013) (“It is
important to note that even with a 1,000 ppm limit, the facility
would be in non-compliance at least three times during the
sampling period.”). Petitioners’ admission that they could not
comply even with a 1000 parts per million wastewater limit
shows that, whether EPA had set the limit at 112 parts per


7
 Intervenors’ expert re-conducted EPA’s analysis without using the
data point that Petitioners contend is faulty, and the fresh
calculation produced a new limit of 112 parts per million. See
Intervenors’ Addendum, Sahu Dec. ¶¶ 9-12, Ex. B.
                              18
million or 110 parts per million, the different limit’s impact
on Petitioners likely would have been de minimis or zero.

    Petitioners have not attempted to articulate how the
court’s failure to enjoin the Rule based on their other
unpreserved objections would result in irreparable harm.
They have not established that their procedural objections
mean that the Rule is likely to change after reconsideration.
Nor have they established that the PVC-combined process
vent emissions limits will differ so dramatically after
reconsideration that attempting to comply in the meantime
with the existing Rule will result in wasteful investments in
unnecessarily stringent control technologies.

     Because Petitioners have not shown that EPA’s delay
violates a statutory right to timely decision making or will
otherwise cause them irreparable harm, they are not entitled to
immediate judicial review of their unpreserved claims.
Petitioners’ challenges stemming from the inadequacy of
notice and comment, to the PVC-combined process vent
limits, and to the wastewater limits—all first raised in
petitions for reconsideration before EPA—are barred from
review at this time.

                             IV.

     Petitioners argue that, if the court cannot immediately
review their unpreserved claims, it should stay the
effectiveness of the challenged aspects of the Rule pending
the outcome of EPA’s reconsideration proceeding. For the
reasons outlined in the preceding Part, they have failed to
show that awaiting the completion of EPA’s reconsideration
will cause them irreparable harm. See Part III, supra; Nken v.
Holder, 556 U.S. 418, 434 (2009) (outlining the requirements
for obtaining a stay); D.C. Circuit Rule 18(a)(1). Petitioners
are accordingly not entitled to a stay.
                               19
     The dissent contends that the Court should stay the major
source wastewater limit because “EPA itself does not oppose
a stay in this case.” Dissent at 1. But that oversimplifies
EPA’s position and does not account for the interests of other
stakeholders who supported the rule and who themselves
stand to suffer harm from EPA inaction.

     In its briefing and at oral argument EPA was emphatic: it
did not waive its non-merits, threshold defense that
Petitioners are barred from challenging the wastewater limits
because they failed to object to them during the notice and
comment period. Resp. Br. 33-35; Oral Arg. Rec. at 30:00-
32:00; 40:30-45:00. EPA contended that, if the court found
the issue to be properly before the court, then and only then
would EPA “not oppose” a stay or vacatur of the wastewater
limits. Resp. Br. 35.

     EPA’s consent is not alone a sufficient basis for us to stay
or vacate a rule. The court is not bound to accept, and indeed
generally should not uncritically accept, an agency’s
concession of a significant merits issue. Cf. Bowen v.
Georgetown Univ. Hosp., 488 U.S. 204, 212-13 (1988)
(holding that courts will not defer to an agency’s litigating
position where it contradicts the agency’s prior “regulations,
rulings, or administrative practice”). The risk is that an
agency could circumvent the rulemaking process through
litigation concessions, thereby denying interested parties the
opportunity to oppose or otherwise comment on significant
changes in regulatory policy. If an agency could engage in
rescission by concession, the doctrine requiring agencies to
give reasons before they rescind rules would be a dead letter.
See Motor Vehicle Mfrs. Ass’n of U.S., Inc. v. State Farm
Mut. Auto. Ins. Co., 463 U.S. 29, 52 (1983).
                              20
     We note, moreover, that the Clean Air Act provides that
“the effectiveness of [a] rule may be stayed during . . .
reconsideration . . . by the Administrator [of the EPA] or the
court for a period not to exceed three months.”
42 U.S.C. § 7607(d)(7)(B). The partial dissent contends that
the Court may stay a Clean Air Act rule indefinitely,
notwithstanding that language, pointing to the more general
stay provisions of the Administrative Procedure Act, 5 U.S.C.
§ 705, and our decision in Portland Cement Assoc. v. EPA,
665 F.3d 177, 189 (D.C. Cir. 2011) (per curiam), which
granted a stay pending reconsideration without explicitly
squaring it with the Clean Air Act’s three-month limitation.
We need not reconcile the divergent authorities on the stay
question however, because, even assuming the court’s power
to grant them one, Petitioners have failed to show irreparable
harm warranting a stay.

                              V.

     Petitioners’ preserved challenges to the substance of
EPA’s Rule fail on their merits. EPA’s PVC-combined
process vent limits do not conflict with other emissions limits,
and EPA’s decision not to subcategorize process vents on the
basis of their emissions control technology was reasonable.
EPA’s bypass opening requirements are not arbitrary and
capricious, and its requirement that PVC manufacturers install
monitoring equipment on pressure relief devices is not
irrational. Finally, Petitioners’ argument that some of EPA’s
bypass regulations are unlawful beyond-the-floor MACT
requirements stems from misapprehension of the Clean Air
Act and is without merit.

     First, the Rule’s PVC-combined process vent limits do
not create a regulatory conflict with other emissions limits.
Petitioners insist that because PVC-combined process vent
                              21
limits, by their very nature, incidentally limit emissions from
sources outside the PVC source category, the Rule creates a
conflict with the emissions limits applicable to those other
sources. But, as EPA explained in the preamble to the present
Rule, overlapping limits are not necessarily “conflicting” or
“inconsistent.” PVC Rule, 77 Fed. Reg. at 22,865 (internal
quotation marks omitted). If a PVC manufacturer chooses to
discharge combined emissions from PVC and non-PVC
processes through a single vent, that manufacturer must
comply with limits applicable to both and, where they differ,
comply with the more stringent of the two. Id. If the two
limits rely on different methods of measurement, both
methods must be used. See id. That may be burdensome, but
it is neither unachievable nor unreasonable. Manufacturers
hold the keys to this particular regulatory box. They can
avoid the overlap, as EPA explained, by separating PVC-
production emissions from those emanating from other
sources. Id. If they do so, the PVC-only process vent limits
will apply to the emissions from PVC production, and the
other source’s relevant emissions limits will apply to its
emissions, eliminating the requirement that the other source
comply with the PVC-combined emissions limits. Id.

     Second, EPA reasonably decided not to subcategorize
process vents on the basis of which particular emissions
control technology PVC manufacturers choose.               The
conclusion that EPA need not—indeed should not—relax its
emissions limits when polluters use insufficiently effective
control technology is inherent in the very idea of technology-
forcing regulation. Petitioners contend, however, that the
superior effectiveness of their emissions control technology is
not accurately measured by EPA’s approach.

   The thrust of Petitioners’ argument is as follows: Most
PVC production facilities use “thermal oxidizers” to reduce
                              22
their emissions into the atmosphere of hazardous air
pollutants. Some, however, use “vent gas absorbers,” a
control technology with a “radically different” emissions
profile from that of a thermal oxidizer. Pet. Br. 52. Thermal
oxidizers vent continuously and at high flow rates; vent gas
absorbers vent intermittently and at very low flow rates.

     EPA’s method of determining compliance with the
Rule’s process vent limits relies on measuring the
concentration of hazardous air pollutants in a process vent’s
effluent stream. A difference in how the two technologies
operate means a vent gas absorber’s effluent stream has a
higher maximum concentration of hazardous air pollutants
than does the relatively consistent effluent stream from a
thermal oxidizer. Petitioners contend that EPA inaccurately
rates vent gas absorbers as less effective than thermal
oxidizers at controlling emissions because of the higher
concentration of pollutants that vent gas absorbers emit. Vent
gas absorbers may nonetheless be a better emissions control
technology than thermal oxidizers, Petitioners claim, because
they emit their relatively concentrated pollutants only
intermittently and at lower rates. The Rule’s focus on the
concentration of hazardous air pollutants means that vent gas
absorbers rate poorly even though they may in fact be more
effective.

     Spelling out the objection makes it immediately clear that
Petitioners’ real dispute is not with inadequate
subcategorization. Petitioners concede that it was reasonable
for EPA to require vent gas absorbers and thermal oxidizers to
meet the same emissions limits.           Instead, Petitioners’
grievance appears to be that the Rule’s method of measuring
the emission of hazardous air pollutants erroneously
concludes that vent gas absorbers are less effective emissions
controls than thermal oxidizers. Petitioners’ claim, in effect,
                              23
is that EPA acted arbitrarily and capriciously in failing to
create an alternate method of measuring output from a PVC
process vent on the basis of the total mass of hazardous air
pollutants it emits, rather than on the basis of the
concentration of hazardous air pollutants in its effluent
stream.

     EPA, however, reasonably chose not to create an
alternative measurement format on the basis of total mass
emission rates. In the Rule, EPA explained that it “considered
setting alternative formats for the process vent emission
limits” but that, in its judgment, it “did not have sufficient
information provided from industry on process vent stream
flow rates and concentrations to develop or evaluate other
formats, such as mass emission rates.” PVC Rule, 77 Fed.
Reg. at 22,869. Petitioners counter that EPA’s explanation is
insufficiently specific and that its want of specificity alone
suffices to render it arbitrary and capricious. See Ne. Md.
Waste Disposal Auth. v. EPA, 358 F.3d 936, 949 (D.C. Cir.
2004). We disagree. EPA’s explanation, though short, fully
conveys the agency’s rationale in declining to set an
alternative measurement format and furnishes concrete
grounds for framing a challenge to the decision’s substantive
rationality. Petitioners have done so, arguing that EPA had
sufficient information to set alternative emissions formats.
Pet. Br. 53. On the merits, Petitioners have not carried their
burden of showing that, contrary to EPA’s explanation, it did
in fact have sufficient data to establish an alternative
emissions format. We defer to EPA’s judgments about data
insufficiency, at least in the absence of further information or
explanation from Petitioners regarding why deference is
inappropriate. Petitioners’ challenge to EPA’s decision not to
subcategorize process vents on the basis of their emissions
control technology therefore lacks merit.
                              24
     Third, EPA’s bypass-opening requirements are not
arbitrary and capricious. Petitioners argue that EPA’s
regulations make opening a bypass unlawful without
exception, even if the opening occurs during routine
maintenance after performing the equipment opening steps
called for elsewhere under the Rule governing maintenance,
and that compliance with the Rule is therefore impossible.
Pet. Br. 55-56 (citing 40 C.F.R. §§ 63.11955, 63.11930(c)).
Petitioners misread EPA’s regulations. The regulations
anticipate that regulated entities will be allowed to open
bypasses during maintenance as long as they comply with the
opening         provisions        set       forth      therein.
40 C.F.R. §§ 63.11955(a)-(b). Otherwise, the very existence
of regulations setting forth instructions for opening bypasses
would be superfluous. In the preamble to the Rule, EPA
explained that it does not interpret 40 C.F.R. § 63.11930(c) as
categorically prohibiting all discharges through bypasses. See
PVC Rule, 77 Fed. Reg. at 22,885. EPA’s interpretation of its
own regulations is entitled to our deference. See Auer v.
Robbins, 519 U.S. 452, 462-63 (1997). In view of the text of
EPA’s regulations and the Agency’s repeated representations
about their meaning, Petitioners’ claims that EPA’s
regulations arbitrarily and capriciously prohibit opening
bypasses for purposes of routine maintenance are without
merit.

     Fourth, EPA’s requirements for monitoring pressure
relief devices are not arbitrary and capricious. Pressure relief
devices are important safety equipment that, if not built to
route emissions through emissions controls, may, when
triggered, emit significant amounts of hazardous air pollutants
directly into the atmosphere. See PVC Rule, 77 Fed. Reg. at
22,881-82. EPA requires that all releases by pressure relief
devices meet the Rule’s process vent emissions limits. 40
C.F.R. § 63.11915(c)(1). EPA provides for two methods of
                              25
compliance: (1) PVC manufacturers may route discharges
from pressure relief devices through emissions control
equipment to ensure compliance with the Rule, or (2) equip
their pressure relief devices with release indicators to detect
uncontrolled discharges. 40 C.F.R. § 63.11915(c)(1)-(2).
EPA concluded that such monitoring is necessary to ensure
that uncontrolled emissions will be “identified and controlled
in a timely manner” and that “repeat problems” will be
corrected. PVC Rule, 77 Fed. Reg. at 22,882.

     Petitioners contend the regulation is unreasonable,
however, because EPA did not have enough data about
hazardous air pollutant releases from pressure relief devices to
justify imposing a costly monitoring requirement. According
to Petitioners, releases from pressure relief devices may be so
rare, insignificant, and well prevented or well detected by
current industry monitoring methods that the regulation is
wasteful and unnecessary. EPA responded in the Rule by
explaining that, in its judgment based on the data in the
record, PVC facilities had not been effectively detecting and
recording releases from pressure relief devices. PVC Rule, 77
Fed. Reg. at 22,882.

     EPA’s judgment was reasonable. The paucity of data
about the frequency and severity of discharges from pressure
relief devices could be because the PVC industry lacks
effective methods for detecting or recording releases. If EPA
were required to gather exhaustive data about a problem for
which gathering such data is not yet feasible, the agency
would be unable to act even if such inaction had potentially
significant consequences. We have consistently held that, in
situations in which an agency must make a judgment in the
face of a known risk of unknown degree, the “agency has
some leeway reasonably to resolve uncertainty, as a policy
matter, in favor of more regulation or less.” Ctr. for Auto
                                 26
Safety v. Fed. Highway Admin., 956 F.2d 309, 316 (D.C. Cir.
1992). Here, the agency’s choices were to do nothing,
consistent with PVC manufacturers’ assertions that their
current efforts were adequate, or promulgate a regulation to
protect against risk. See PVC Rule, 77 Fed. Reg. at 22,881-
82. Petitioners point to some data EPA had on certain devices
and claim EPA ignored it. But, as EPA explained in the Rule,
that data did not give EPA reason to believe that all PVC
manufacturers have and use effective discharge detection and
recording technology. Id. EPA recognized the high stakes of
the decision to do nothing, explaining that releases from
pressure relief devices “have the potential to emit large
quantities of [hazardous air pollutants], and a large number of
these releases that may occur may not be identified and
controlled in a timely manner, and may be due to repeat
problems that have not been corrected.” Id. at 22,882. EPA
thus reasonably exercised its broad discretion to require
monitoring of pressure relief devices to ensure compliance
with the Rule’s emissions limits.

     Fifth, EPA’s regulations designed to ensure the detection
of discharges through bypasses are not beyond-the-floor
MACT requirements. The Rule requires PVC manufacturers
to install a flow indicator, lock-and-key system, or “car seal”
on bypasses to detect when they are opened. 40 C.F.R. §§
63.11930(c)(1), (2).8 Petitioners contend that EPA failed to
determine whether its regulation would be “achievable” in
light of “cost, energy requirements, and other factors,” as

8
  A car seal may be an inexpensive plastic fastener (e.g., a zip tie)
or a steel cable closed in a loop with a small block of aluminum or
steel. See 40 C.F.R. § 63.12005 (defining “Car-seal” as “a seal that
is placed on a device that is used to change the position of a valve .
. . in such a way that the position of the valve cannot be changed
without breaking the seal”).
                              27
EPA is required to do before imposing a beyond-the-floor
MACT limit under Section 112(d)(2) of the Clean Air Act.
Sierra Club v. EPA, 353 F.3d 976, 989 (D.C. Cir. 2004); see
42 U.S.C. § 7412(d)(2). Petitioners’ argument lacks merit
because EPA’s bypass Rule simply is not a beyond-the-floor
MACT requirement and so is not subject to Section 112(d)(2).
The requirement was enacted pursuant to EPA’s statutory
authority under Section 114(a)(1)(C), permitting the agency to
require the installation, use, and maintenance of monitoring
equipment to ensure compliance with a MACT emissions
limit. See 42 U.S.C. § 7414(a)(1)(C); PVC Rule, 77 Fed. Reg.
at 22,860. Bypass flow indicators, locks, and car seals are all
monitoring devices: they determine whether a PVC facility is
in violation of the Rule by identifying either mechanically (as
with a flow indicator) or visually (as with an open lock or
broken seal) an open bypass that may discharge pollutants.
EPA reasonably and lawfully required PVC manufacturers to
install, use, and maintain them pursuant to Section
114(a)(1)(C). We therefore reject Petitioners’ argument that
EPA’s bypass monitoring regulation somehow triggers
Section 112(d)(2)’s cost-benefit requirements.

                            ***

     For the foregoing reasons we deny the petitions for
review.
     KAVANAUGH, Circuit Judge, dissenting in part: EPA
issued a rule that imposes limits on emissions of hazardous air
pollutants by manufacturers of polyvinyl chloride. But EPA
later concluded that one category of those limits – the so-
called wastewater limits on hazardous air pollutants that may
be dissolved in wastewater – was based on bad data. EPA is
therefore reconsidering the wastewater limits. EPA says that
it will complete the reconsideration process in 2016.

     Petitioners, who are manufacturers of polyvinyl chloride,
contend that EPA’s flawed wastewater limits should be stayed
under 5 U.S.C. § 705, the general Administrative Procedure
Act provision authorizing stays pending judicial review.
Petitioners are correct. They obviously have demonstrated a
likelihood of success on the merits; after all, EPA concedes
that the wastewater limits are flawed. And petitioners also
have shown irreparable harm – namely, the high costs to
comply with the flawed wastewater limits. Moreover,
petitioners have precedent on their side: In a similar case in
which EPA was reconsidering a concededly flawed rule, we
readily granted a stay. See Portland Cement Association v.
EPA, 665 F.3d 177, 189 (D.C. Cir. 2011) (“We will, however,
enter a stay of the NESHAP standards applicable to clinker
storage piles. EPA has conceded that it ‘did not give
sufficient notice’ of those standards and has granted PCA’s
request for reconsideration . . . . Thus, industry should not
have to build expensive new containment structures until the
standard is finally determined.”).

    Even EPA itself does not oppose a stay in this case.
EPA’s position is telling. Given the circumstances here, as
well as our Portland Cement precedent, I would stay the
wastewater limits pending judicial review.

     To be sure, the Clean Air Act imposes a 3-month limit on
stays pending agency reconsideration.        See 42 U.S.C.
§ 7607(d)(7)(B). But Section 705 of the APA authorizes
                                2
courts to stay agency rules pending judicial review without
any time limit on the duration of the stay. See 5 U.S.C. § 705
(reviewing court “may issue all necessary and appropriate
process to postpone the effective date of an agency action or
to preserve status or rights pending conclusion of the review
proceedings”); In re GTE Service Corp., 762 F.2d 1024, 1026
(D.C. Cir. 1985) (Section 705 provides “statutory authority to
stay agency orders pending review in this court.”). 1
Therefore, in this case, we should issue a stay that remains in
effect pending judicial review.

    For those reasons, I respectfully dissent from the majority
opinion’s decision not to stay EPA’s wastewater limits. 2




    1
       The Clean Air Act does not displace Section 705, the general
APA provision governing stays pending judicial review. The Clean
Air Act expressly provides that several provisions of the APA – 5
U.S.C. §§ 553-557 and 706 – “shall not, except as expressly
provided in this subsection, apply to actions to which this
subsection applies.” 42 U.S.C. § 7607(d)(1). Section 705 is not on
that list. By contrast, Congress has displaced Section 705 in other
statutory regimes. Cf. 16 U.S.C. § 1855(f)(1) (fishery management
regulations subject to judicial review in accordance with
Administrative Procedure Act, but not with Section 705); id.
§ 3636(c) (Pacific salmon fishing regulations subject to judicial
review in accordance with Administrative Procedure Act, but not
with Section 705). Had Congress wanted to prevent courts in Clean
Air Act cases from issuing stays under Section 705, Congress could
have done so.
     2
        Petitioners also challenge EPA’s process vent emissions
limits and the compliance and monitoring provisions. I agree with
the majority opinion that those claims lack merit.
