UNITED STATES COURT OF APPEALS FOR THE D.C. CIRCUIT


NAT RESRC DEF CNCL

v.

EPA


97-1727a

D.C. Cir. 1999


*	*	*


Sentelle, Circuit Judge: Natural Resources Defense  Council, Inc.
("NRDC") challenges the Environmental Protec- tion Agency's enhanced
emission source monitoring rule,  known as Compliance Assurance
Monitoring, promulgated  pursuant to the 1990 Clean Air Act
Amendments. Various  industry groups challenge EPA's "any other
material infor- mation" certification requirement which pertains to
collecting  evidence to prove or disprove Clean Air Act compliance. 
After considering the parties' arguments and reviewing the  record, we
hold that EPA's enhanced monitoring system  complies with the Clean
Air Act Amendments except for the  portion pertaining to "continuous
or intermittent" compliance  certification. We also hold that the
issue raised by the  industry groups is unripe for review.


I. Background


A. Enhanced Monitoring


Section 114(a) of the Clean Air Act vests EPA with the  authority to
require emissions data collection in order to  enable the agency to
develop emissions standards and deter- mine compliance with those
standards. See 42 U.S.C. 


s 7414(a) (1994). The Clean Air Act also provides EPA with  the
authority to enforce those standards. See 42 U.S.C.  s 7413. Prior to
1990, most air pollution sources' emissions  were tested at start-up
or another single point in time. See  Enhanced Monitoring Program, 58
Fed. Reg. 54,648, 54,658  (1993) (proposed Oct. 22, 1993). At that
time, there was no  statutory mechanism outside of EPA, state
regulators, and  citizen surveillance to ensure the requisite
compliance moni- toring. See id. In 1990, Congress enacted amendments
to  the Clean Air Act intended to enhance emissions source  monitoring
and compliance and to impose new monitoring and  reporting
requirements on emissions sources. Specifically,  the new amendments
sought to identify and clarify the kinds  of data to be collected and
to require major sources to  monitor their emissions and report their


As amended, s 114 of the Clean Air Act provides in part:


[T]he [EPA] Administrator may require any person who  owns or operates
any emission source, who manufactures  emission control equipment or
process equipment, who  the Administrator believes may have
information neces- sary for the purposes set forth in this subsection,
or who  is subject to any requirement of this chapter ... on a 
one-time, periodic or continuous basis to ... (D) sample  such
emissions (in accordance with such procedures or  methods, at such
locations, at such intervals, during such  periods and in such a
manner as the Administrator shall  prescribe) [and] (E) keep records
on control equipment  parameters, production variables or other
indirect data  when direct monitoring of emissions is


42 U.S.C. s 7414(a)(1)(D)-(E) (emphasis added). This provi- sion gives
EPA the authority to require a source to keep  relevant emissions data
when direct sampling is impractical  and to require a source to
conduct emission sampling. Con- gress added a new subsection in 1990
pertaining to major  source monitoring, stating that EPA


shall in the case of any person which is the owner or  operator of a
major stationary source, and may, in the  case of any other person,
require enhanced monitoring 


and submission of compliance certifications. Compliance  certification
shall include ...


(C) the [source's] compliance status,


(D) whether compliance is continuous or intermittent,  [and]


(E) such other facts as the Administrator may require.


Id. s 7414(a)(3) (emphasis added). Thus, Congress expressed  an
intention to obligate major sources to a more stringent  reporting


Section 504 of the Clean Air Act establishes the major  source
permitting program's requirements and contains pro- visions related to
monitoring and compliance certification.  Section 504(a) requires that
each permit "shall include en- forceable emission limitations and
standards ... and such  other conditions as are necessary to assure
compliance with  applicable requirements." 42 U.S.C. s 7661c(a).
Subsection  (b) elaborates that "[t]he Administrator may by rule
prescribe  procedures and methods for determining compliance and for 
monitoring and analysis of pollutants regulated under this  chapter,
but continuous emissions monitoring need not be  required if
alternative methods are available that provide  sufficiently reliable
and timely information for determining  compliance." Id. s 7661c(b).
Thus, s 504 establishes that  EPA may promulgate rules that require
implementing a  compliance and monitoring method which provides
"sufficient- ly reliable" information for determining compliance.


In 1993, EPA proposed a broad regulatory scheme that  would have
required a major source to provide an emissions  compliance statement
and proof of continuous compliance.  The proposal would have resulted
in direct emissions monitor- ing in most instances. However, following
public comment  sessions, EPA decided to adopt an alternative approach
in  1997. EPA abandoned the more rigorous 1993 proposal in  response
to industry and state and local pollution control  agencies' comments
that the proposal was too costly given the  benefits involved, too
burdensome on local permitting authori- ties, inconsistent with
congressional intent regarding costs,  and likely to stifle innovation
due to high costs. See Compli-


ance Assurance Monitoring Rulemaking (40 C.F.R. Parts 64,  70, and 71),
Responses to Public Comments (Part I) (October  2, 1997).


EPA ultimately adopted a new approach, Compliance As- surance
Monitoring ("CAM"), which requires major sources  using pollution
control devices to employ parametric monitor- ing. See 40 C.F.R. ss
64.2, 64.3(a) (1998). The CAM pro- gram allows major sources to comply
with monitoring re- quirements by identifying specific operational
parameters and  providing data that enforcement entities can use to
determine  whether the source falls within the appropriate operating 


Under CAM, EPA requires that major source owners  "establish ...
appropriate range(s) ... for the selected indi- cator(s) such that
operation within the ranges provides a  reasonable assurance of
ongoing compliance with emission  limitations or standards." 40 C.F.R.
s 64.3(a)(2). CAM also  imposes an affirmative requirement on each
major source to  bring its emissions within the acceptable range when
the  source falls outside the acceptable range. See 40 C.F.R.  s
64.7(d). Specifically, the source must "restore operation of  the
pollutant-specific emissions unit (including the control  device and
associated capture system) to its normal or ususal  manner of
operation as expeditiously as practicable...." Id.  CAM expands upon
prior emissions monitoring by providing  major sources with a
mechanism to implement self- monitoring and self-checks on compliance.
For reasons set  forth more fully below, NRDC challenges the adequacy
of  EPA's attempt to comply with the Clean Air Act Amend- ments.


B. Other Material Information and Credible Evidence


To comport with the CAM approach, EPA amended its  Part 70/71 major
source permit compliance requirements.  Under the revision, each major
source must identify its  compliance methodology and identify whether
that methodol- ogy provides continuous or intermittent data. See 40
C.F.R.  ss 70.6(c)(5)(iii)(B), 71.6(c)(5)(iii)(B). The revision also


quires major sources "if necessary, ... [to] identify any other 
material information that must be included in the certification  to
comply with section 113(c)(2) of the Act, which prohibits  knowingly
making a false certification or omitting material  information." Id.
ss 70.6(c)(5)(iii)(B), 71.6(c)(5)(iii)(B). Sec- tion 113(c)(2) creates
criminal liability for "[a]ny person who  knowingly ... makes any
false material statement, represen- tation, or certification in, or
omits material information from,  or knowingly alters, conceals, or
fails to file or maintain any  notice, application, record, report,
plan, or other document  required pursuant to this chapter." 42 U.S.C.


During the rulemaking period in issue, EPA separately  promulgated
another rule, the Credible Evidence Rule  ("CER"), which provides that
nothing shall preclude the use  of any credible evidence or
information in demonstrating  compliance or noncompliance with
national emission stan- dards. See 40 C.F.R. ss 52.12(c); 60.11(g);
61.12(e). The  preamble to the CER reconfirmed that credible evidence
may  be used in permit enforcement actions and compliance certifi-
cations. See Credible Evidence Revisions, 62 Fed. Reg. 8314,  8316-17
(1997). However, EPA further stated that the "revi- sions do not call
for the creation or submission of any new  emissions or parametric
data, but rather address the role of  existing data in enforcement
actions and compliance certifica- tions" and that the agency "in no
way intends to alter the  underlying emission standards." Id. at 8316;
see also 62  Fed. Reg. at 8314-15.


Industry groups, led by Appalachian Power Company ("Ap- palachian"),
challenge the "any other material information"  requirement as beyond
EPA's authority and as a violation of  their due process rights.


II. NRDC Challenge


Both NRDC and the industrial challengers petitioned this  court for a
review of EPA's actions pursuant to 42 U.S.C.  s 7607(b)(1), which
provides that all challenges to nationally  applicable regulations
under the Clean Air Act must be  brought in the United States Court of
Appeals for the District 


of Columbia Circuit. After exercising this jurisdiction under 
applicable legal standards, we conclude that with one excep- tion the
challenges either are not justiciable or do not war- rant judicial


A. Enhanced Monitoring


NRDC challenges the adequacy of EPA's CAM program to  meet the enhanced
monitoring requirements of the Clean Air  Act Amendments on multiple
grounds. NRDC first asserts  that CAM does not substantively comply
with s 114(a)(3)'s  enhanced monitoring mandate. Specifically, NRDC
contends  that CAM exempts so many major sources from its coverage 
that its lack of coverage should invalidate the rule. Further,  NRDC
argues that CAM's "reasonable assurance of compli- ance" standard does
not assure compliance as required by the  Clean Air Act or assure
compliance as a factual matter. In  addition, NRDC claims that the
length of CAM's phase-in  period creates an unreasonable delay.
Finally, NRDC as- serts that EPA's requirement that a major source
certify only  whether its report is based on "continuous or
intermittent  data," 40 C.F.R. s 70.6(c)(5)(iii)(B) (emphasis added),
does  not meet the Clean Air Act's explicit requirement that "[c]om-
pliance certifications shall include ... whether compliance is 
continuous or intermittent," 42 U.S.C. s 7414(a)(3) (emphasis  added).
We conclude that only the last challenge merits  relief.


NRDC's challenge to EPA's adoption of CAM in further- ance of the
"enhanced monitoring" requirement of s 114(a)(3)  questions the
interpretation of a statute by the agency en- trusted with the
administration of that statute. Therefore,  we apply the classic
two-step test of Chevron U.S.A., Inc. v.  Natural Resources Defense
Council, Inc., 467 U.S. 837  (1984), which provides that in such
review we first look to the  statute's language and give effect to any
"unambiguously  expressed intent of Congress," but if the statute is
ambigu- ous or silent with regard to the matter at issue, we accept 
the agency's interpretation, provided that interpretation is  merely
reasonable. Id. at 842-43, 845. The phrase "en-


hanced monitoring" as used in s 114(a)(3) is sufficiently am- biguous
to invoke the second step of the Chevron analysis.  As EPA pointed
out, section 114(a)(3) does not specify any  particular type of
enhanced monitoring. Nothing in the  phrase "enhanced monitoring"
supports NRDC's view that  only continuous or direct emissions
monitoring can be re- garded as "enhanced" or that CAM cannot be
deemed "en- hanced." Nonetheless, NRDC argues that CAM cannot con-
stitute "enhanced monitoring" since it exempts numerous  sources from
its coverage, does not assure "sufficiently reli- able" compliance as
required by s 504(b), and does not in  fact provide even a "reasonable
assurance of compliance."  We reject these arguments for several


First, CAM is not invalid on the basis that it does not cover  certain
major sources (e.g., those that do not utilize emission  control
devices and those that fail the 100-tons-per-emission- point test).
True, s 114(a)(3) plainly subjects all major  sources to enhanced
monitoring and, as NRDC points out,  EPA exempts many major sources
from CAM's coverage.  However, the 1990 Clean Air Act Amendments did
not man- date that EPA fit all enhanced monitoring under one rule and 
EPA has reasonably illustrated how its enhanced monitoring  program,
when considered in its entirety, complies with  s 114(a)(3). Cf. NRDC
v. EPA, 22 F.3d 1125, 1141-42 (D.C.  Cir. 1994) (finding EPA's
explanation for excepting certain  areas from coverage under a
particular rule reasonable given  statute's broad mandate and EPA's
overall regulatory plan).  Specifically, EPA demonstrated that many of
the major sta- tionary sources exempt from CAM are subject to other 
specific rules, and if they are not, they are subject to the 
following two residual rules: (1) "[The permit shall contain] 
periodic monitoring sufficient to yield reliable data ... that  are
representative of the source's compliance with the per- mit...." 40
C.F.R. s 70.6(a)(3)(i)(B); (2) "All part 70 per- mits shall contain
the following elements with respect to  compliance: (1) Consistent
with paragraph (a)(3) of this sec- tion, compliance certification,
testing, [and] monitoring ...  requirements sufficient to assure
compliance with the terms  and conditions of the permit." Id. s


While the Part 70 rules are not as specific as CAM, they  have the same
bottom line--a major source must undertake  "monitoring ... sufficient
to assure compliance." Like CAM,  the monitoring protocols will be
developed on a unit-by-unit  basis. Such monitoring is sufficiently
"enhanced" over the  pre-1990 situation to satisfy the statutory
requirement. See  Compliance Assurance Monitoring, 62 Fed. Reg.
54,900,  54,904 (1997).


Second, EPA provides a reasonable basis for its conclusion  that CAM
will be effective in assuring emissions limit compli- ance. NRDC
contends that there is no across-the-board  evidence that monitoring
control parameters will assure com- pliance and that EPA does not
require control parameters to  be statistically correlated with actual
emissions standards.


We will not set aside a final rule under the Clean Air Act  unless the
underlying agency action was "arbitrary, capri- cious, an abuse of
discretion, or otherwise not in accordance  with law" or "in excess of
statutory jurisdiction, authority, or  limitations, or short of
statutory right." 42 U.S.C.  s 7607(d)(9)(A) & (C). The "arbitrary and
capricious" stan- dard deems the agency action presumptively valid
provided  the action meets a minimum rationality standard. See, e.g., 
Small Refiner Lead Phase-Down Task Force v. EPA, 705  F.2d 506, 520-21
(D.C. Cir. 1983). In applying this standard  we determine whether the
agency has considered the relevant  factors and articulated a rational
connection between the facts  and its choices. See Motor Vehicle Mfrs.
Ass'n of the United  States v. State Farm Mut. Auto. Ins. Co., 463
U.S. 29, 43  (1983). While we carefully review the factual record, we
will  give due deference to the agency especially when the agency 
action involves evaluating complex scientific or statistical data 
within the agency's expertise. See Ethyl Corp. v. EPA, 541  F.2d 1,
34-36 (D.C. Cir. 1976) (en banc).


Applying that standard of review to the rule before us, we  conclude
that EPA's adoption of CAM survives NRDC's  challenge. As EPA argues,
across-the-board evidence is un- necessary since CAM requires major
source owners, on a  unit-by-unit basis, to "establish ... appropriate
range(s) ... 


for the selected indicator(s) such that operation within the  ranges
provides a reasonable assurance of ongoing compli- ance with emission
limitations." 40 C.F.R. s 64.3(a)(2).  Thus, CAM enhances monitoring
by requiring each major  source owner to design a site-specific
monitoring system  sufficient to provide a reasonable assurance of
compliance  with emissions standards. See id. s 64.3(a), (a)(2). More-
over, as EPA made clear at oral argument, this standard does  require
a major source owner to establish a correlation  between the control
parameters and emission limits. We  cannot therefore conclude that the
EPA has failed to consider  relevant factors or articulate a rational
connection between  the facts and its choices. For the same reasons,
we conclude  CAM satisfies the "sufficiently reliable" compliance
require- ment of s 504(b). We therefore apply the statutorily mandat-
ed deference to the agency's judgment and deny the NRDC's 


Third, NRDC misconstrues s 114(a)(1)(D)-(E) as requiring  EPA to
mandate direct enhanced monitoring of major sources  unless EPA finds
such monitoring "impractical." We agree  with EPA that CAM was
promulgated under subsection (a)(3)  of s 114 rather than under
subsection (a)(1). Section  114(a)(1) gives EPA the option to require
("the Administrator  may require") certain kinds of monitoring whereas
 s 114(a)(3) squarely requires enhanced monitoring ("the Ad-
ministrator shall ... require enhanced monitoring"). Since  CAM falls
into the required enhanced monitoring category  and s 114(a)(3) does
not contain language requiring an im- practicality finding, EPA did
not have to make an impractical- ity finding before choosing to
monitor major source control  parameters rather than to monitor


Finally, NRDC erroneously believes that CAM does not  effectuate the
congressional intent behind the 1990 Clean Air  Act Amendments because
CAM fails to "facilitate" enforce- ment. See S. Rep. No. 101-228, at
368 (1989). NRDC argues  that since CAM monitoring data do not
establish source  compliance or noncompliance, the data lack the value
neces- sary to be used as probative evidence in enforcement pro-
ceedings. However, as we stated before, EPA reasonably  concluded that
CAM will provide a reasonable assurance of 


compliance with emissions limitations. Thus, EPA "facili- tates"
enforcement under any reasonable definition of the  term since CAM
monitoring provides evidence that will be  relevant in any enforcement


In sum, we hold that EPA's adoption of CAM as "enhanced  monitoring"
meets the requirements of the Clean Air Act.


B. CAM Phase-In


EPA's decision to phase in the CAM requirements as major  source
permits are renewed is reasonable. EPA acknowl- edges that some major
sources applying for permits will come  under CAM's coverage over the
next two to three years while  some sources will not be phased-in for
approximately five to  eight years because CAM requirements will not
apply to  them until their next permit renewal. See 40 C.F.R.  s
70.4(b)(3)(iii), (iv) (stating that permits are renewed or  reviewed
every five years). However, EPA reasonably decid- ed to phase-in CAM
requirements based on the already- existing licensing structure in
order to lessen the burden on  sources and state licensing authorities
and to create a  learning-curve for implementation. See 62 Fed. Reg.
54,902- 03, 54,927-28 (1997). Nor does NRDC point to a compulsory 
implementation deadline or offer a basis for second-guessing  the
agency at this point in time. See NRDC, 22 F.3d at 1137- 40 (implying
deference to the agency regarding implementa- tion when statute silent
regarding implementation deadline).  Given the circumstances, EPA
offers a reasonable explanation  for the extended phase-in plan.


C. Continuous or Intermittent Compliance


Despite CAM's validity, we hold that EPA's certification  regulations
are inconsistent in one particular with  s 114(a)(3)(D)'s statutory
mandate. While s 114(a)(3) clearly  states that a major source's
"compliance certification shall  include ... whether compliance is
continuous or intermit- tent[,]" EPA only requires that a major
source's compliance  certification include "[t]he identification of


used by the owner ... for determining the compliance status  ... and
whether such methods ... provide continuous or  intermittent data." 40
C.F.R. ss 70.6(c)(5)(iii)(B),  71.6(c)(5)(iii)(B). The statute
requires that certification in- clude whether "compliance"--not just
"data"--is continuous  or intermittent.


Although EPA may permit owners to certify compliance  within the degree
of certainty that CAM provides, it may not  eliminate the "check off"
requirement altogether. We do not  reach the second step of the
Chevron analysis on this ques- tion. Where Congress has expressed its
unmistakable intent  in the plain words of the statute, our review
ends with step  one. See Nuclear Information Resource Service v.
Nuclear  Regulatory Commission, 969 F.2d 1169, 1173 (D.C. Cir.  1992)
(en banc). It will not save EPA's failure to meet the  statutory
requirement that there is ambiguity in other sec- tions of the
statute. It is only where "the statute ... is  'silent or ambiguous
with respect to the specific issue' before  us" that "we 'defer to the
agency's interpretation of the  statute.' " Id. (quoting Chemical
Manufacturers Ass'n v.  EPA, 919 F.2d 158, 162-63 (D.C. Cir. 1990)).
Here, Congress  expressly and unambiguously required that the
certification  include "whether compliance is continuous or
intermittent."  EPA's regulations do not effectuate that expressed


III. Industry Groups' Challenge


Industry groups challenge EPA's requirement that compli- ance
certifications be based on "any other material informa- tion,"
including "credible evidence," as impermissibly increas- ing the
stringency of emissions standards. We, as we have  before, conclude
that the industry groups' challenge is unripe  for review.


In Clean Air Implementation Project v. EPA, 150 F.3d  1200 (D.C. Cir.
1998) ("CAIP"), various industry groups chal- lenged EPA's "credible
evidence" rule revisions by alleging  that the changes effectively
increased the stringency of the  underlying emissions standards
contrary to proper rulemak-


ing procedures. See id. at 1201, 1203. We held that, absent  any
demonstrable "great hardship," the industry groups'  stringency
challenge would be unripe for review until EPA  actually brought a
"credible evidence" enforcement proceed- ing against a source. Id. at


The industry groups here, led by Appalachian, contend that  CAIP's
ripeness analysis is not applicable to the present  challenge because,
unlike in that case, delaying a decision  here will cause hardship to
source owners. They argue that a  hardship will occur because in being
required to use "other  material information" in their certifications,
source owners  will be required to "abandon any rights they might have
to  defend against the use of that evidence in enforcement pro-
ceedings." Appalachian Br. at 15. Whatever the merits of  that
argument might otherwise be, it does not appear that its  factual
underpinnings are sound in the present controversy.  That is, it is
not apparent that source owners will be required  to abandon any such


At oral argument, EPA counsel agreed with the court's  supposition that
nothing precludes an owner from adding a  caveat to its certification
to the effect that, while it is provid- ing other evidence which EPA
might find material, the sub- mitter disputes its materiality and
reserves the right to  challenge the use of the evidence in court.
Counsel for  Appalachian then agreed that the ability to use such
disclaim- er language "solves our problem." We agree. In other  words,
Appalachian's challenge on this ground is still not ripe.


In attacking the information requirement, Appalachian also  argues that
"any other information" and "credible evidence"  as employed by EPA
are such facially vague terms as to  violate the due process rights of
the regulated entities. Ap- palachian's void-for-vagueness attack also
fails due to ripe- ness considerations. Specifically, since
Appalachian does not  contend that the "any other material
information" rule is  vague in every circumstance, its facial
challenge collapses and  it must wait until there is an actual
enforcement proceeding  to make a specific challenge that will be


Conclusion


To recap, we hold that CAM complies with the Clean Air  Act's "enhanced
monitoring" requirement, EPA supplied a  reasonable basis for the CAM
phase-in schedule, and the  industry groups' challenge to EPA's
"credible evidence" and  "other material information" requirements is
unripe for re- view.


Each major source must, however, certify whether its  compliance is
"continuous or intermittent." We therefore  remand the portion of CAM
pertaining to "continuous or  intermittent" compliance certification
to EPA for it to revise  its regulation to accord with our decision,
but affirm EPA in  all other respects.


So ordered.