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United States Court of Appeals
FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued October 9, 2003 Decided June 18, 2004
No. 02-1282
MOSSVILLE ENVIRONMENTAL ACTION NOW
AND SIERRA CLUB,
PETITIONERS
v.
ENVIRONMENTAL PROTECTION AGENCY AND
CHRISTINE TODD WHITMAN, ADMINISTRATOR,
U.S. ENVIRONMENTAL PROTECTION AGENCY,
RESPONDENTS
VINYL INSTITUTE, INC.,
INTERVENOR
–————
On Petition for Review of an Order of the
Environmental Protection Agency
–————
James S. Pew argued the cause and filed the briefs for
petitioners.
Brian H. Lynk, Attorney, U.S. Department of Justice,
argued the cause for respondents. With him on the brief
were G. Scott Williams, Attorney, and Andrew G. Gordon,
Attorney, Environmental Protection Agency. Christopher S.
Bills of costs must be filed within 14 days after entry of judgment.
The court looks with disfavor upon motions to file bills of costs out
of time.
2
Vaden, Attorney, U.S. Department of Justice, entered an
appearance.
Before: SENTELLE, RANDOLPH and ROGERS, Circuit Judges.
Opinion for the Court filed by Circuit Judge SENTELLE.
SENTELLE, Circuit Judge: Petitioners Mossville Environ-
mental Action Now and Sierra Club seek review of an Envi-
ronmental Protection Agency (‘‘EPA’’) rule styled ‘‘National
Emission Standards for Hazardous Air Pollutants for Polyvi-
nyl Chloride and Copolymers Production.’’ 67 Fed. Reg.
45,886 (July 10, 2002) (‘‘the Part 63 NESHAP’’). This rule,
adopted pursuant to section 112 of the Clean Air Act
(‘‘CAA’’), set emission standards for PVC and Copolymer
production facilities that mirrored EPA’s previous rule, artic-
ulated at 41 Fed. Reg. 46,560 (Oct. 21, 1976); 40 C.F.R.
Subpart F (§§ 61.60 – 61.71) (‘‘the Part 61 NESHAP’’ or ‘‘the
Part 61 standard’’), because the EPA determined that the
Part 61 NESHAP were the most stringent controls in the
industry.
Petitioners contend that EPA has failed to meet the re-
quirements of the CAA in setting various limits for vinyl
chloride emission. They further contend that EPA erred in
failing to set emission limits for all of the other hazardous air
pollutants (‘‘HAPs’’) emitted during PVC production. Two of
petitioners’ arguments regarding vinyl chloride emissions lim-
its have been waived, and we do not find meritorious their
remaining challenges to those limits. We do, however, hold
that EPA has failed properly to set emissions limits on other
HAPs, as required by the CAA. The petition is therefore
granted in part and denied in part.
I. Background
A. Statutory Background
This is the latest in a series of challenges to rulemakings
establishing emission standards for HAPs in various indus-
tries under the 1990 revisions to the CAA. See, e.g., North-
east Md. Waste Disposal Auth. v. EPA, 358 F.3d 936 (D.C.
3
Cir. 2004) (per curiam) (municipal waste combustors); Sierra
Club v. EPA, 353 F.3d 976 (D.C. Cir. 2004) (copper smelters);
Cement Kiln Recycling Coalition v. EPA, 255 F.3d 855 (D.C.
Cir. 2001) (hazardous waste combustors); Nat’l Lime Ass’n v.
EPA, 233 F.3d 624 (D.C. Cir. 2000) (portland cement manu-
facturing facilities); Sierra Club v. EPA, 167 F.3d 658 (D.C.
Cir. 1999) (medical waste incinerators); Appalachian Power
Co. v. EPA, 135 F.3d 791 (D.C. Cir. 1998) (per curiam)
(electric utility boilers).
Section 112 of the CAA was amended in 1990 to include a
congressionally established list of HAPs. 42 U.S.C.
§ 7412(b)(1). Vinyl chloride is included on that list. Id. The
CAA directs the EPA to establish categories and subcatego-
ries of major sources that emit one or more of the enumerat-
ed HAPs. Id. § 7412(c). The statute further requires the
EPA to issue technology-based emission standards, known as
National Emission Standards for Hazardous Air Pollutants
(‘‘NESHAP’’), for those sources. There are essentially two
steps in this process.
The CAA establishes a minimum required reduction–known
as the maximum achievable control technology floor (‘‘MACT
floor’’). The MACT floor for new sources ‘‘shall not be less
stringent than the emission control that is achieved in prac-
tice by the best controlled similar source, as determined by
the Administrator.’’ Id. § 7412(d)(3). For existing sources:
Emission standards TTT may be less stringent than
standards for new sources in the same category or
subcategory but shall not be less stringent, and may
be more stringent than –
(B) the average emission limitation achieved by the
best performing 5 sources (for which the Adminis-
trator has or could reasonably obtain emissions in-
formation) in the category or subcategory for cate-
gories with fewer than 30 sources.
Id.
Once floor standards are established, the EPA determines
if standards more stringent than those actually achieved by
4
the best performing sources are possible. These standards
must
require the maximum degree of reduction in emis-
sions of the hazardous air pollutants subject to this
section (including a prohibition on such emissions,
where achievable) that the Administrator, taking
into consideration the cost of achieving such emis-
sion reduction, and any non-air quality health and
environmental impacts and energy requirements, de-
termines is achievable for new or existing sources in
the category or subcategory to which such emission
standard applies[.]
Id. § 7412(d)(2). These are known as ‘‘beyond-the-floor’’
standards. In setting beyond-the-floor standards, the EPA is
to ‘‘require the maximum degree of reduction in emission of
the hazardous air pollutant’’ that is achievable
through application of measures, processes, meth-
ods, systems or techniques including, but not limited
to, measures which –
(A) reduce the volume of, or eliminate emissions
of, such pollutants through process changes, substi-
tution of materials or other modifications,
(B) enclose systems or processes to eliminate
emissions,
(C) collect, capture or treat such pollutants when
released from a process, stack, storage or fugitive
emissions point,
(D) are design, equipment, work practice, or oper-
ational standards (including requirements for opera-
tor training or certification) as provided in subsec-
tion (h) of this section, or
(E) are a combination of the above.
Id. The EPA must balance these considerations with other
factors such as cost, non-air-quality health and environmental
concerns, and energy implications. Id. This technology-
based regime replaced an earlier risk-based regime that
5
required EPA to regulate at a level that provided an ample
margin of safety to protect the public.
Additionally, section 112(d)(1) requires the EPA to set
emission standards for every HAP emitted from each catego-
ry or subcategory of major sources. Id. § 7412(d)(1); see
also Nat’l Lime Ass’n v. EPA, 233 F.3d 625, 634 (D.C. Cir.
2000) (‘‘National Lime’’) (stating EPA has ‘‘the clear statuto-
ry obligation to set emission standards for each listed HAP’’).
B. Regulatory Background
Vinyl chloride, a gas that is highly toxic and a known
human carcinogen, is the starting point for PVC and copolym-
er production. It is first pressurized and agitated in a
reactor, resulting in polymerization. Once polymerized, vinyl
chloride can be transformed into many diverse products, from
latex paints to PVC piping. Vinyl chloride can enter the
atmosphere in several ways during PVC production. The gas
can escape to the atmosphere when equipment is opened for
routine maintenance, either through leaks in the production
system, or by being present in such low concentrations that it
escapes through recovery systems in exhaust streams. This
form of pollution is often referred to as ‘‘stack emissions’’ or
‘‘exhaust gasses.’’ There is also some residual vinyl chloride
in the PVC itself, know as residual vinyl chloride monomer
(‘‘RVCM’’). RVCM is removed from the PVC through a
process known as stripping. Stripping results in vinyl chlo-
ride emissions as well. Those emissions are often referred to
as ‘‘process equipment emissions’’ or ‘‘RVCM emissions.’’
In 1976, prior to the 1990 implementation of technology-
based standards, the EPA promulgated emission standards
for vinyl chloride under the risk-based standard then in
effect. 41 Fed. Reg. 46,560 (Oct. 21, 1976); 40 C.F.R. Sub-
part F (§§ 61.60 – 61.71) (‘‘the Part 61 NESHAP’’). Perti-
nent to this case, under the Part 61 standard EPA regulated
exhaust gasses from the reactors of polyvinyl chloride plants
at ten parts per million (‘‘ppm’’) averaged over a three-hour
period. See, e.g., 40 C.F.R. § 61.64(a)(1). RVCM emissions
were regulated at 2000 ppm per plant for PVC dispersion
6
resins, excluding latex resins, 40 C.F.R. § 61.64(e)(1)(i), and
400 ppm per plant for all other PVC resins, averaged daily.
Id. at § 61.64(e)(1)(ii).
When Congress amended the CAA in 1990, it required the
EPA within ten years to review its emission standards to
ensure compliance with the amended CAA. 42 U.S.C.
§ 7412(q)(1). Pursuant to this command, EPA addressed the
Part 61 NESHAP in two separate rules. The first, known as
the Hazardous Organic NESHAP (‘‘HON Rule’’), addresses
and supersedes the Part 61 NESHAP as it relates to the
production of ethylene dichloride and vinyl chloride. 57 Fed.
Reg. 31,576 (July 16, 1992); see 40 C.F.R. part 63, subparts
F, G, and H (40 C.F.R. §§ 63.100 – 63.182). The HON Rule,
however, explicitly excludes batch operations, such as PVC
production, from its scope. 40 C.F.R. § 63.100(j)(4). Be-
cause batch operations were covered by the Part 61 NESH-
AP, another rulemaking was required to deal with the Part 61
NESHAP’s application to batch operations, including PVC
production. That rule is the Part 63 NESHAP at issue here.
To set the Part 63 standards, the EPA first determined
that twenty-eight sources in the United States produce PVC
and all are subject to the Part 61 NESHAP. 65 Fed. Reg. at
76,962/1. The EPA then considered state emission require-
ments and determined that the Part 61 NESHAP require-
ments, not state requirements, had the greatest influence on
emission controls. The EPA further determined that no
better technology was available than the Part 61 standard
already required. Looking specifically at RVCM emission
from PVC resins, the EPA recognized that while some states
had more stringent standards in place, those standards were
based on quarterly averages, while the Part 61 standard was
based on daily limits. Id. The EPA found that comparing
these standards was difficult because of the different measur-
ing periods. In addition, the EPA found that the amount of
RVCM emission is primarily dependent on what type of PVC
resins each plant manufactures. There is thus a wide varia-
tion of RVCM emission during normal operation, and EPA
found that the daily limits ensure that operators keep average
RVCM emission low so that the spikes do not cause the
7
average to violate the daily limits. The EPA also found that
the most stringent state standards had been imposed on
plants that produced PVC resins that were the most capable
of stripping to low RVCM levels. 65 Fed. Reg. at 76,962/1.
Because these state limitations were specific to the products
at each plant, EPA determined that the state permit limits
were not generally applicable.
In sum, the EPA concluded that the Part 61 NESHAP
satisfied all of the requirements set forth in the 1990 amend-
ments, and adopted almost all of the old Part 61 NESHAP
standards as the new Part 63 NESHAP standards. Thus, the
Part 61 standards became the ‘‘floor’’ for existing sources
pursuant to section 112 of the CAA. The EPA then declined
to adopt beyond-the-floor measures, citing, inter alia, the
possibility that certain PVC production would be prohibited if
more stringent standards were adopted.
Additionally, the EPA determined that it was unnecessary
to set separate individual emission standards for all other
HAPs that result from PVC production, as required by
section 112(d)(1), because it could simply use vinyl chloride as
a surrogate for those other HAPs. This, according to the
EPA, was because the stripping, scrubbing, incineration, or
combination thereof, that is required under the Part 61
standard limits emission of all HAPs, not just vinyl chloride.
Unsatisfied with these standards, petitioners have sought
review of the Part 63 NESHAP here.
II. Analysis
This Court sets aside final EPA action under the CAA if
that action is arbitrary, capricious, an abuse of discretion, or
otherwise not in accordance with law. 42 U.S.C. § 7607(d)(9);
see Motor Vehicle Mfrs. Ass’n v. State Farm Mut. Auto. Ins.
Co., 463 U.S. 29, 41 (1983). Under this familiar standard,
‘‘[a]gency determinations based upon highly complex and
technical matters are ‘entitled to great deference.’ ’’ Appala-
chian Power Co. v. EPA, 249 F.3d 1032, 1051-52 (D.C. Cir.
2001) (per curiam) (quoting Public Citizen Health Research
Group v. Brock, 823 F.2d 626, 628 (D.C. Cir. 1987)).
8
A. Waiver
We first deal with whether certain of petitioners’ claims are
properly before us. The EPA contends that two of petition-
ers’ challenges–that EPA erred in setting the floor for ex-
haust gasses and erred in failing to establish beyond-the-floor
standards–were waived as they were not properly raised
before the agency below. We turn first to EPA’s establish-
ment of a floor for exhaust gasses.
In its rulemaking, the EPA determined that no more
stringent limits applied to vinyl chloride exhaust gas streams
than the ten ppm limit in the Part 61 NESHAP, and estab-
lished that limit as the floor. 65 Fed. Reg. at 76,962/2.
Petitioners claim that their concerns regarding this issue
were sufficiently raised in two letters submitted to the EPA
by parties not involved in this case. The question is whether
these letters were sufficiently specific to raise the issue
before the EPA.
The first is a February 8, 2001 letter from the State and
Territorial Air Pollution Programs Administrators (‘‘STAP-
PA’’) and the Association of Local Air Pollution Control
Officials (‘‘ALAPCO’’) to the EPA (‘‘STAPPA Letter’’). That
letter addresses different aspects of the rule, but with respect
to the setting of MACT floors it specifically addresses the 400
ppm standard for ‘‘residual vinyl chloride in the PVC slurry.’’
Indeed, it mentions the 400 ppm standard, which applies to
RVCM emissions, four times in the six paragraphs that
address the MACT floor. It does not, however, ever mention
the ten ppm standard that applies to exhaust emissions. Nor
do those paragraphs ever mention ‘‘gasses’’ or ‘‘exhaust.’’
The letter thus did not specifically challenge the ten ppm
exhaust gas limit.
In an effort to avoid the lack of a specific challenge,
petitioners argue that nothing in the letter directly limits the
fact that ‘‘their objection is a general one to EPA’s floor
approach.’’ This will not do. ‘‘Only an objection to a rule or
procedure which was raised with reasonable specificity during
the period for public comment (including any public hearing)
may be raised during judicial review.’’ 42 U.S.C.
9
§ 7607(d)(7)(B). We ‘‘strictly’’ enforce this requirement.
Motor & Equip. Mfrs. Ass’n v. Nichols, 142 F.3d 449, 462
(D.C. Cir. 1998) (internal quotation marks and citation omit-
ted). Reasonable specificity requires something more than a
‘‘general [challenge] to EPA’s approach.’’ The language in
the letter that petitioners rely upon is a sentence, in the last
paragraph addressing MACT floors, that states that ‘‘control
device performance and capabilities and process improve-
ments have evolved’’ to a point below the Part 61 standards.
According to petitioners, because only the ten ppm standard
is based on the performance of control devices, it is clear that
the comments were not limited to the 400 ppm floor. This
fails. In a letter so obviously focused on the 400 ppm
standard, such general reference in the closing paragraph
does not rise to the ‘‘reasonable specificity’’ required by the
statute.1
The second letter that petitioners claim raised the issue is
dated February 12, 2001 and is from the State of Louisiana to
the EPA (‘‘the Louisiana Letter’’). This two-page letter also
does not mention the ten ppm standard, but again directly
addresses RVCM emissions. It does, however, have an at-
tached table, which the letter claims proves that state limits
are more stringent than the Part 61 standards. One of the
eight columns in the table is labeled ‘‘Misc. Process Vents,’’
and includes data that could be exhaust limits. Again, and
for the reasons stated above, this does not meet the standard
of reasonable specificity. The letter does not directly address
the ten ppm standard, and attaching a table that cryptically
refers to miscellaneous process vents does not automatically
put the EPA on notice of a challenge to every piece of
information contained in the table. In sum, petitioners’ chal-
lenge to the floor on exhaust gasses is waived because it was
not raised with reasonable specificity to the agency below.
1Petitioners also point to a sentence in the letter requesting the
EPA to use ‘‘all readily available data, including the data provided
under Subpart F.’’ Petitioners’ argument that, because Subpart F
contains data for both the ten and 400 ppm standards, the EPA was
on notice fails for the same reasons as articulated above.
10
We now turn to petitioners’ claim that EPA erred in failing
to establish beyond-the-floor standards pursuant to CAA
section 112(d)(2). 42 U.S.C. § 7412(d)(2). EPA again claims
that this argument is waived. For their part, petitioners
again point to the STAPPA and Louisiana letters as bringing
the beyond-the-floor concerns to the attention of the EPA.
In our view, both the STAPPA and Louisiana letters fail to
raise the beyond-the-floor issue with reasonable specificity.
The Louisiana letter consists of four numbered paragraphs.
The first paragraph, by its own language, addresses the
‘‘MACT Floor.’’ The fourth deals with EPA’s failure to
regulate other HAPs. The second and third paragraph pres-
ent petitioners’ best argument that Louisiana raised the issue,
but they are simply not specific enough. The second para-
graph states that Louisiana permits are ‘‘more stringent than
the currently proposed MACT requirements.’’ The third
paragraph describes the Part 61 standard as ‘‘old,’’ and
asserts that better technology is available. While these two
paragraphs could imply not only a challenge to the setting of
the MACT floor, but also a challenge to EPA’s failure to set
beyond-the-floor standards, that is all it does – potentially
imply a challenge. There is no mention of beyond-the-floor
standards.
It is just not clear that the State of Louisiana, in a letter
that contained specific and clear challenges to the setting of
the RVCM MACT floor, was also challenging the beyond-the-
floor standards. While petitioners may argue that it is
obvious that if one challenges the floor, one is also implicitly
challenging the failure to set beyond-the-floor standards, that
is not the way the regulatory system is structured. Such a
standard would require agencies to review perpetually all of
the ‘‘implied’’ challenges in any challenge they receive. We
will not impose such a burden on the agency. All that
Louisiana had to do was draft one sentence that specifically
challenged EPA’s decision. It did not, and that specific
challenge is thus not preserved.
The same is true of the STAPPA letter. It specifically
addresses STAPPA’s concern that EPA’s proposed standard
11
‘‘does not meet the MACT floor requirements of Section
112(d).’’ In closing the pertinent section, STAPPA requests
that the ‘‘EPA recalculate the MACT floor using information
about other sourcesTTTT’’ Like the Louisiana letter, this
letter fails to mention beyond-the-floor standards, nor does it
cite the specific provision of the CAA which deals with them.
In Motor & Equipment Manufacturers, we considered peti-
tioners’ claims waived because they failed to cite the specific
provision to the agency below. 142 F.3d at 462 (holding that
a petitioner’s claim that EPA should comply with CAA sec-
tion 202 does not put the agency on sufficient notice for a
specific claim regarding CAA section 202(b)(1)(C)). Like the
Louisiana letter, the only way the STAPPA letter could be
read as placing the EPA on notice is to place the burden on
EPA to cull through all the letters it receives and answer all
of the possible implied arguments. Such a rule would defeat
the statutory requirement for ‘‘reasonable specificity.’’
B. The RVCM Floor
Petitioners also contend that the EPA violated its statutory
duty by failing to identify the five best performing PVC
plants in setting the RVCM floor. Indeed, the EPA readily
admits that it did not identify the best five performing plants,
even though the CAA specifically requires the EPA to set
floors that
shall not be less stringent, and may be more strin-
gent than –
(B) the average emission limitation achieved by the
best performing 5 sources (for which the Adminis-
trator has or could reasonably obtain emissions in-
formation) in the category or subcategory for cate-
gories with fewer than 30 sources.
42 U.S.C. § 7412(d)(3)(B). Petitioners further point to Ce-
ment Kiln Recycling Coalition v. EPA, where we held that
‘‘EPA may not deviate from section 7412(d)(3)’s requirement
that floors reflect what the best performers actually
achieveTTTT’’ 255 F.3d 855, 861 (D.C. Cir. 2001) (‘‘CKRC’’).
12
The EPA argues that in this case, determining the best five
sources was impossible. This is because of the great variabil-
ity in RVCM emissions, and the fact that that variability is a
result of the type of resin being produced, not the technology
or processes applied to control emission. 67 Fed. Reg. at
45,889/2-3. According to the EPA, there can even be great
variability in RVCM emission at the same PVC plant, which
would obviously employ the same technology and processes
on a day-to-day basis, if that plant produces a variety of
resins, which most do. Id. at 45,887/2. With comparisons
between plants impossible, and emission variations not relat-
ed to technological performance, the EPA claims it was
unable to select the best five sources. Therefore, after
considering other alternatives, it determined that since all
twenty-eight PVC plants were subject to the Part 61 NESH-
AP, those standards estimated the best five performing
sources.
In testing the EPA’s reliance on the Part 61 NESHAP, we
look to our earlier in-depth treatment of this and similar
provisions of the CAA. In Sierra Club v. EPA, the Sierra
Club challenged the EPA’s methodology when it ‘‘ranked TTT
incinerators by the stringency of the control provisions to
which they were subject’’ and then ‘‘selected the 12 percent of
the incinerator population subject to the strictest controls and
set the floor TTT by averaging the emissions limitations
governing those incinerators.’’ 167 F.3d at 661. Sierra Club
challenged the use of regulatory data for determining floors
because the statute in that case required, almost exactly as
the statute presently before us required, that ‘‘[e]missions
standards TTT shall not be less stringent than the average
emissions limitation achieved by the best performing 12 per-
cent of units in the category.’’ 42 U.S.C. § 7429(a). Noting
that ‘‘this phrase on its own says nothing about how the
performance of the best units is to be calculated,’’ Sierra
Club, 167 F.3d at 661, we held that EPA need not base its
standards on actual data, but could lawfully rely on estimates
drawn from the regulatory data as to what the best perform-
ing 12 percent were achieving. Id. at 663. Ultimately,
however, we remanded that decision to the agency because
13
EPA had ‘‘not pointed to evidence supporting the reasonable-
ness of the approximation.’’ Id.
In National Lime, we heard another challenge to EPA’s
methodology, that time with respect to the statute presently
before us, CAA section 112. Relying heavily on Sierra Club,
we rejected a petitioner’s claim that textual differences in
CAA sections 129 and 112 mandated a different analysis.
National Lime, 233 F.3d at 632. There, EPA selected ‘‘the
median [performing] plant out of the best twelve percent of
the plants for which it had information and set the TTT floor
at the level of the worst performing plant in its databases
using th[e same] technology [as the median plant].’’ Id. at
630. Again, we held that CAA section 112 allowed the EPA
to ‘‘reasonably estimate’’ the performance of the top 12
percent rather than use the actual data, as long as the
estimate was reasonable. Id. at 633. We held that Sierra
Club had not offered a reason in the record to show EPA’s
estimate was not reasonable. Id.
In CKRC, we again reiterated our earlier position, enunci-
ated in our Sierra Club and National Lime decisions, that
EPA could use estimates if reasonable, but in a different
context. There, EPA took the position that section 112
required it to set a standard that could be achieved by the
worst performing plant that utilized MACT control technolo-
gy. CKRC, 255 F.3d at 861. The Sierra Club challenged this
on the basis that section 112 does not limit itself to any one
technology, so EPA was required to consider what the best
performers actually achieved, taking into consideration fac-
tors other than MACT technology. Id. We agreed, and held
that ‘‘the worst performing MACT source do[es] not, as the
CAA requires, represent a reasonable estimate of emissions
achieved by the best-performing sources.’’ Id. at 865. We
also reiterated that EPA could use estimates, as long as they
reflected a ‘‘reasonable[ ] estimate [of] the performance of the
TTT best-performing plants.’’ Id. at 862. In CKRC, EPA
failed to make the connection.
Most recently, in Northeast Maryland Waste Disposal
Authority v. EPA, we rejected EPA’s efforts to use state
14
permit limits as the MACT floor for pollutants from small
municipal waste combustion units. 358 F.3d 936, 953-54 (D.C.
Cir. 2004) (‘‘NMWDA’’). There, ‘‘[a]s in Sierra Club, EPA
stated only that it ‘believes’ state permit limits reasonably
reflect the actual performance of the best performing units
without explaining why this is so.’’ Id. at 954. EPA only
asserted that the inherent variability of emission levels made
its data inaccurate, but gave ‘‘no evidence that the [state]
permit levels reflect the emission levels of the best-
performing’’ plants. Id. EPA’s belief did not rise to the
level of a reasonable estimate.
Turning to the present case, EPA again cites the variability
of emission, which EPA claims makes the lower state limits
inappropriate. This, EPA explained, is because the state
permit levels are tailored to the specific products at each
plant, and typically use a longer averaging time in order to
require a lower average limit. More importantly, however,
instead of simply claiming that it believes its Part 61 stan-
dards estimate what the best five plants actually achieve,
EPA points to some evidence. In its response to comments,
EPA cited its analysis of three years of data, and showed that
even ‘‘the facility that had the lowest overall long term
RVCM experienced significant variation in daily averages
including one daily (three hour) average of 397 ppm.’’ EPA
Response to Comments at 6, April 2002. Thus, the 400 ppm
daily standard contained in the Part 61 standard is just
barely satisfied by the plant with the lowest overall long term
RVCM. EPA has thus pointed to factual data that the Part
61 standard reasonably estimates the performance of the top
performers, because even the best performing sources occa-
sionally have spikes, and under the standard, each facility
must meet the 400 ppm standard every day and under all
operating conditions. The EPA has met it burden of estab-
lishing that its standards reasonably estimate the perform-
ance of the best five performing sources. Having cited the
great variability of emission levels, even within the same
plants, and the inherent difficulty in other standards it con-
sidered, the EPA’s selection of the Part 61 standards as the
MACT floor is reasonable because it has supported its deci-
15
sion with record data that shows the connection between its
MACT floor and the top performing plants.
C. Use of Vinyl Chloride as a Surrogate
Petitioners also challenge the EPA’s failure to establish
emission standards for every HAP that PVC plants emit. We
have held that this requirement, spelled out in CAA section
112(d)(1), establishes a ‘‘clear statutory obligation to set emis-
sion standards for each listed HAP’’ that the source category
emits. Nat’l Lime, 233 F.3d at 634. Instead, according to
petitioners, EPA simply utilized the Part 61 NESHAP, which
addresses only vinyl chloride. Petitioners argue that this
fails under both the first and second step of the familiar
Chevron analysis, and in the alternative, that it is arbitrary
and capricious because EPA has failed to present any evi-
dence that its vinyl chloride regulations regulate all other
HAPs.
For its part, EPA contends that it simply utilized vinyl
chloride as a surrogate for the other HAPs. EPA makes
several attempts to defend this effort, none of which can save
it. First, in EPA’s view, National Lime merely requires
‘‘that there [be] a correlation between [the surrogate and the
other HAPs]; it need not quantify that correlation or assess
its variability.’’ Id. at 639. In EPA’s own words, ‘‘if [it] can
demonstrate that the necessary correlation exists, the agency
may use a surrogate and avoid full-blown application of
Section 112 for each hazardous air pollutant emitted from an
industry.’’ EPA’s problem is that, assuming, without decid-
ing, this is all that is required, it completely failed to do so.
We have clearly held that ‘‘EPA may use a surrogate to
regulate hazardous pollutants if it is reasonable to do so.’’
Nat’l Lime, 233 F.3d at 637. In assessing the reasonableness
of EPA’s use of a surrogate in that case, we held that because
EPA had demonstrated that there are always HAP metals in
particulate matter (the surrogate), and thus that the removal
of the particulate matter removed the HAP metals, EPA had
satisfied its burden. Id. at 639; see also Sierra Club v. EPA,
353 F.3d 976 (D.C. Cir. 2004). The EPA found no such
correlation here.
16
The EPA asserts that it ‘‘is aware of no statutory or
regulatory provision or any case law imposing’’ the require-
ment that ‘‘EPA must identify each and every pollutant
controlled through a surrogate under Section 112(d).’’ The
EPA reads the requirement that it establish a correlation
between the surrogate and the HAP it is attempting to
regulate as not requiring identification of the HAP it is
attempting to regulate. To clarify EPA’s position, it contends
that ‘‘[p]rovided EPA reasonably determined TTT a link exist-
ed between vinyl chloride controls and other hazardous air
pollutants, it should make no difference whether EPA has
identified each of the other hazardous air pollutants emitted
by the industry.’’ While EPA may be able to know that a
correlation exists between one known pollutant and some
other unknown pollutants, it has not memorialized that knowl-
edge in such a fashion that commenters, interested members
of the public, regulated entities, or most importantly, a re-
viewing court, can assess. We cannot review under any
standard the adequacy of the EPA’s correlation determina-
tion if we do not know what correlation the EPA found to
exist. The closest the EPA comes to supplying record sup-
port for its determination is a reference to tables included in
the administrative record showing what other hazardous air
pollutants were emitted by various plants at various locations.
These charts take up several pages of the joint appendix, and
we have no way of knowing what EPA’s claims are as to
which of the HAPs are represented by surrogacy or to what
degree. In short, we do not find EPA’s explanation persua-
sive, and hold that its determination that vinyl chloride is a
surrogate for all other HAPs emitted from PVC production
facilities is arbitrary and capricious and not supported in the
record. Therefore, EPA’s use of vinyl chloride as a surrogate
for other HAPs emitted from PVC plants is remanded to the
agency for more a adequate explanation.
III. Conclusion
The petition is denied in part and granted in part. The
Part 63 NESHAP is vacated and remanded to the agency for
17
it to reconsider or properly explain its methodology for
regulating HAPs emitted in PVC production other than vinyl
chloride by use of a surrogate. All of petitioners’ remaining
claims are either not properly before us, or are not meritori-
ous.