                        United States Court of Appeals

                     FOR THE DISTRICT OF COLUMBIA CIRCUIT


             Argued April 21, 1998      Decided August 14, 1998 

                                 No. 97-1117

                 Clean Air Implementation Project, et al.,  

                                 Petitioners


                                      v.


                      Environmental Protection Agency, 

                                  Respondent


                 Natural Resources Defense Council, Inc. and 

                       Battery Council International, 

                                 Intervenors


                            Consolidated with Nos.

            97-1125, 97-1130, 97-1142, 97-1169, 97-1173, 97-1179,

            97-1190, 97-1195, 97-1226, 97-1241, 97-1242, 97-1253,

            97-1254, 97-1259, 97-1261, 97-1266, 97-1269, 97-1273,

             97-1278, 97-1281, 97-1282, 97-1283, 97-1286, 97-1289

                  On Petition for Review of an Order of the 

                       Environmental Protection Agency


---------
     Henry V. Nickel and William H. Lewis, Jr., argued the 
cause for petitioners.  With them on the briefs were Mel S. 
Schulze, Lauren E. Freeman, David E. Menotti, William F. 
Pedersen, Joshua D. Sarnoff, Gene E. Godley, Robert N. 
Steinwurtzel, Howard B. Myers, Roger Walker, Leslie Sue 
Ritts, Chris S. Leason, Robert Brager, David Friedland, 
Christina Franz, Alexandra Dapolito Dunn, Julie Hatcher, 
Michael H. Levin, Michael McGovern, Lynn L. Bergeson, 
Bethami Auerbach, Robert L. Brubaker, Janet J. Henry, 
Paul G. Wallach, Kenneth R. Meade, Jerome H. Heckman, 
Peter L. de la Cruz, William M. Bumpers, Debra J. Jezouit, 
Jennifer S. Leete, John L. Wittenborn, Chet M. Thompson, 
Edwin H. Seeger and  Jane C. Luxton.  David F. Zoll and 
Richard A. Flye entered appearances. 

     Karen L. Egbert and Patricia Ross McCubbin, Attorneys, 
U.S. Department of Justice, argued the cause for respondent.  
With them on the brief were Lois J. Schiffer, Assistant 
Attorney General, Robert G. Dreher and Gregory B. Foote, 
Counsel, U.S. Environmental Protection Agency.  Cecilia E. 
Kim, Attorney, U.S. Department of Justice, entered an ap-
pearance.

     William H. Lewis, Jr., Joshua D. Sarnoff and David B. 
Weinberg were on the brief for intervenor Battery Council 
International.

     Gail Lewkowicz was on the brief for amici curiae State 
and Territorial Air Pollution Program Administrators (STAP-
PA) and Association of Local Air Pollution Control Officials 
(ALAPCO).

     Before:  Silberman, Williams, and Randolph, Circuit 
Judges.

     Opinion for the Court filed by Circuit Judge Randolph.

     Randolph, Circuit Judge:  Petitioners Clean Air Implemen-
tation Project and other trade associations 1 brought this 

__________
     1  The trade associations represent various industry groups, 
including car manufacturers, lumber companies, steel producers, 
petroleum companies, and mining companies.


action for judicial review of the Environmental Protection 
Agency's rule permitting the use of "credible evidence" to 
prove or disprove violations of the Clean Air Act, 42 U.S.C. 
ss 7401 et seq.  They allege that the rule is illegal for various 
reasons, including lack of statutory authority and unlawful 
revision of substantive standards.  We hold that the issues 
they raise are unripe and cannot be decided at this time.

                                      I


     The Clean Air Act directs the EPA Administrator to devel-
op and promulgate three types of air pollution standards.  
National ambient air quality standards ("NAAQS"), issued 
under s 109, 42 U.S.C. s 7409, specify the maximum permis-
sible concentrations of six criteria pollutants in the air.  See 
40 C.F.R. pt. 50.  The Act makes states primarily responsible 
for the attainment and maintenance of the NAAQS through 
state-designed implementation plans, see 42 U.S.C. s 7410, 
also called "SIPs," which EPA must approve and which 
become federally enforceable once approved, see id. 
s 7413(a).  Performance standards issued pursuant to s 111, 
42 U.S.C. s 7411, regulate emissions of air pollutants from 
newly constructed or modified stationary sources.  See 40 
C.F.R. pt. 60.  Emission standards for stationary sources of 
hazardous air pollutants for which no ambient air quality 
standard is applicable are issued pursuant to s 112, 42 U.S.C. 
s 7412.2  See 40 C.F.R. pt. 61.  EPA may enforce these 
standards through administrative, civil, or, with the assistance 
of the Attorney General, criminal actions.  See 42 U.S.C. 
s 7413.

     Before EPA adopted its credible evidence rule in February 
1997, 62 Fed. Reg. 8314, the agency's air pollution standards 
specified not only the maximum permissible level of emis-
sions, but also the performance or reference test that should 
be used as a means of sampling and analyzing air pollutants 

__________
     2  In the Clean Air Act Amendments of 1990, Congress rewrote 
s 112 to include a list of 189 toxic air pollutants that EPA was 
required to regulate.  However, s 112(q) provides that standards in 
effect before the date of enactment "shall remain in force and effect 
after such date."


for the particular standard.  See, e.g., 40 C.F.R. ss 60.2, 
61.02.  A reference test is any "generic multi-use test proto-
col[ ] that measure[s] whether a source's emissions comply 
with numeric performance standards."  Paul D. Hoburg, Use 
of "Credible Evidence" to Prove Clean Air Act Violations, 25 
B.C. Envtl. Aff. L. Rev. 771, 784-85 (1998).  Subparts of 
Title 40 prescribe reference tests for various emission 
sources.  Appendix A to 40 C.F.R. Part 60, for instance, 
contains more than fifty different test methods for determin-
ing compliance with the new source performance standards.  
See also 40 C.F.R. pt. 61, App. B (listing test methods for 
hazardous air pollutant standards);  40 C.F.R. pt. 51, App. M 
(listing recommended test methods for state implementation 
plans).  In all, there are approximately 130 reference tests, 
although the same test may be "used in connection with many 
different performance standards."  Hoburg, supra, at 785.

     In the rulemaking challenged here, EPA added nearly 
identical language to five sections of its regulations, providing 
that nothing in them "shall preclude the use, including the 
exclusive use, of any credible evidence information, relevant 
to whether a source would have been in compliance with 
applicable requirements if the appropriate performance or 
compliance test or procedure had been performed."  40 
C.F.R. s 60.11(g);  see also 40 C.F.R. ss 51.212(c), 52.12(c), 
52.33(a), and 61.12(e).  The agency based these revisions on 
its "long-standing authority under the Act, and on amplified 
authority provided by the 1990 [Clean Air Act Amendments]," 
specifically s 113(a) and (e), 42 U.S.C. s 7413(a), (e).  62 Fed. 
Reg. 8314.  Section 113 deals with federal enforcement of 
emission standards and, according to its legislative history, 
was amended to enhance EPA's enforcement powers.  See 
S. Rep. No. 101-228, at 358 (1989), reprinted in 1990 
U.S.C.C.A.N. 3385, 3741.  EPA maintains that the "language, 
history and intent" of the 1990 Amendments support its 
credible evidence revisions.  62 Fed. Reg. 8314.

     Nothing in the rule itself defines or limits the possible 
kinds of evidence encompassed within the phrase "credible 
evidence."  EPA explained in the preamble to its final rule:  



"today's rule will make it clear that various kinds of informa-
tion other than reference test data, much of which is already 
available and utilized for other purposes, may be used to 
determine compliance or noncompliance with emission stan-
dards."  62 Fed. Reg. at 8315.  The preamble listed "engi-
neering calculations, indirect estimates of emissions, and di-
rect measurement of emissions by a variety of means" as 
methods on which EPA, state agencies, and industry routine-
ly rely.  Id.  Also mentioned were "continuous emission 
monitoring" and "parametric monitoring" data.  Id.  To illus-
trate, EPA discussed the use of a continuous opacity monitor 
instead of Method 9, the reference test method for opacity.  
Method 9 requires that a "trained visible emissions observer 
(VEO) view a smoke plume with the sun at a certain angle to 
the plume in order to properly illuminate it.  In contrast, a 
continuous opacity monitor (COM) contains a calibrated light 
source that provides for accurate and precise measurement of 
opacity at all times.  Notably, EPA uses COM data to certify 
and re-certify the credentials of VEOs under Method 9."  Id. 
at 8319.  Thus, according to the agency, continuous opacity 
monitoring data would be credible evidence in lieu of Method 
9.  The preamble also cited two citizen suits based on credible 
evidence.  Id. at 8318.  In Sierra Club v. Public Service Co., 
894 F. Supp. 1455 (D.Colo. 1995), the court accepted opacity 
monitoring data and reports as means of proving emissions 
violations.  In Unitek Environmental Servs. v. Hawaiian 
Cement, No. 95-00723 (D.Haw.1996), the court upheld the use 
of evidence that included EPA's notice of violation issued to 
Hawaiian Cement several months before, Hawaiian Cement's 
admission of noncompliance, and results of Hawaiian Ce-
ment's computerized modeling of its own particulate emis-
sions.

     Petitioners argue that EPA promulgated the rule without 
statutory authority, that the revisions are unlawful because 
EPA failed to comply with proper rulemaking procedures, 
and that EPA violated the Clean Air Act by forcing states to 
rewrite their implementation plans.  The heart of the argu-
ment is that the credible evidence rule, by altering the means 
of determining compliance for the new source performance 



standards and the hazardous air pollutant standards, increas-
es the stringency of the underlying standards.  Since EPA 
admittedly did not conduct a rulemaking for each of the 
standards to which the credible evidence rule may be applied, 
petitioners charge that it violated the procedures required by 
the Act.  See 42 U.S.C. s 7607(d).  EPA's short answer is 
that there was no need for such proceedings because the 
standards have not been changed.

                                      II

     Petitioners' theory of the relationship between tests and 
standards is this:  the test method is an integral part of the 
standard itself and the test method should not be changed 
without a full evaluation of the impact such a change might 
have on the standard.  The theory proceeds from the fact 
that in developing its standards, EPA relied on tests showing 
the standards to be consistently achievable using the best 
current technology.  See Brief of Petitioners at 9-10.  EPA 
then used these same test methods to determine compliance 
with the numerical standards it promulgated.  Citing Port-
land Cement Ass'n v. Ruckelshaus, 486 F.2d 375 (D.C. Cir. 
1973), petitioners argue that changing the means of testing 
compliance amounts to changing the standard themselves.  In 
Portland Cement, the court stated that "a significant differ-
ence between techniques used by the agency in arriving at 
standards, and requirements presently prescribed for deter-
mining compliance with standards, raises questions about the 
validity of the standard."  Id. at 396.  There the court 
required EPA to explain the discrepancy between the method 
used to develop the standard and the method used to enforce 
it.  Id. at 397.

     Petitioners' view of the interaction between tests and stan-
dards leads them to two contentions.  First, they assert that 
any change in compliance method or test is substantive 
because "use of a different test method or procedure can lead 
to fundamental differences in results, due to differences in 
analytical method, data reduction, or measurement location."  
Brief of Petitioners at 13-14.  For example, a newer and 


more sensitive test might detect emissions in excess of the 
numerical limit at times when the original reference test 
would show that emissions were below the regulatory ceiling.  
Second, they claim that the credible evidence rule converts 
"periodic" standards to "continuous" ones.  See id. at 35-42.  
That is, sources previously subject to standards based on 
"snapshot" data from infrequent "short-term" tests may now 
have their compliance monitored on an ongoing basis through 
the use of credible evidence.  Id. at 35-36.  Converting a 
periodic standard into a continuous one makes the standard 
more rigorous because, petitioners assert, continuous moni-
toring will capture all the fluctuations and variability inherent 
in emissions and thus increase each source's number of 
"violations."  (According to petitioners, variability in emis-
sions had previously been compensated for by means of 
infrequent testing.)  The issues raised by these contentions 
are not, we hold, justiciable at this time.

     In 1967, three Supreme Court cases, decided in tandem, 
revolutionized judicial review of agency rulemaking.  The 
cases--Abbott Laboratories v. Gardner, 387 U.S. 136;  Toilet 
Goods Ass'n v. Gardner, 387 U.S. 158;  and Gardner v. Toilet 
Goods Ass'n, 387 U.S. 167--dealt with the then-unsettled 
question when, if ever, courts may pass upon the validity of 
an agency regulation prior to its enforcement.  "Before Ab-
bott Laboratories the courts typically reviewed the lawfulness 
of an agency's rule, not when it was promulgated, but when it 
was enforced.  After Abbott Laboratories reviewing practice 
changed radically."  Stephen G. Breyer & Richard B. Stew-
art, Administrative Law and Regulatory Policy 1136 (2d ed. 
1985).  In deciding whether judicial review must await appli-
cation of the rule in the concrete setting of an enforcement 
action, the Supreme Court adopted Judge Friendly's formula-
tion in Toilet Goods Ass'n v. Gardner, 360 F.2d 677, 684 (2d 
Cir. 1966) (quoting Joint Anti-Fascist Refugee Comm. v. 
McGrath, 341 U.S. 123, 156 (1951) (Frankfurter, J., concur-
ring):  there must be an evaluation of "both the fitness of the 
issues for judicial decision and the hardship to the parties of 
withholding court consideration."  Abbott Labs., 387 U.S. at 
149.



     In the three decades since Abbott Laboratories, "preen-
forcement review of agency rules and regulations has become 
the norm, not the exception," Breyer & Stewart, supra, at 
1137, a trend accelerated by Congress' enactment of a host of 
regulatory statutes specifically providing for this.  The review 
provision of the Clean Air Act, 42 U.S.C. s 7607(b), invoked 
here, is typical.  It provides that a petition for judicial review 
must be filed within 60 days of publication of a rule in the 
Federal Register, 42 U.S.C. s 7607(b)(1), and that action of 
the EPA Administrator "with respect to which review could 
have been obtained ... shall not be subject to judicial review 
in civil or criminal proceedings for enforcement," 42 U.S.C. 
s 7607(b)(2).  We have not considered this provision, or like 
provisions in other regulatory statutes, as requiring the court 
to adjudicate issues raised in a preenforcement challenge to a 
rule unless those issues are suitable for decision.  If the 
issues are not of that nature, we will dismiss the petition as 
unripe.  See Louisiana Environmental Action Network v. 
Browner, 87 F.3d 1379, 1385 (D.C. Cir. 1996);  Association of 
American Railroads v. Surface Transportation Bd., No. 
97-1020, 1998 WL 343436, *4 (D.C. Cir. June 30, 1998).3  A 
necessary corollary is that if the issues later become justicia-
ble, as a result for instance of an enforcement action, the 
petitioner may then raise those issues, notwithstanding the 
portion of s 7607(b)(2) just quoted.  See Louisiana Environ-
mental Action Network, 87 F.3d at 1381;  Baltimore Gas & 
Elec. Co. v. ICC, 672 F.2d 146 (D.C. Cir. 1982). 

     As to petitioners' first contention, neither element of the 
Abbott Laboratories inquiry--fitness for judicial decision and 
hardship of denying relief--has been satisfied.  In determin-
ing the fitness of an issue for judicial review we look to see 
whether the issue "is purely legal, whether consideration of 

__________
     3  The purpose of withholding judicial review "is to prevent the 
courts, through avoidance of premature adjudication, from entan-
gling themselves in abstract disagreements over administrative 
policies, and also to protect the agencies from judicial interference 
until an administrative decision has been formalized and its effects 
felt in a concrete way by the challenging parties."   Abbott Labs., 
387 U.S. at 148-49.



the issue would benefit from a more concrete setting, and 
whether the agency's action is sufficiently final."  Natural 
Resources Defense Council, Inc. v. EPA, 22 F.3d 1125, 1133 
(D.C. Cir. 1994) (quoting Her Majesty the Queen ex rel. 
Ontario v. EPA, 912 F.2d 1525, 1532 (D.C. Cir. 1990)).  
EPA's credible evidence rule is final, but in contending that 
the rule alters the standards, petitioners have raised issues 
that are not purely legal, issues that are not suitable for 
decision in the abstract.  See Truckers United for Safety v. 
Federal Highway Administration, 139 F.3d 934 (D.C. Cir. 
1998).  Judicial resolution of these issues would benefit signif-
icantly from having "the scope of the controversy ... reduced 
to more manageable proportions, and its factual components 
fleshed out, by some concrete action applying the regulation 
to the [petitioners'] situation in a fashion that harms or 
threatens to harm" them.  Lujan v. National Wildlife Fed'n, 
497 U.S. 871, 891 (1990).

     As matters now stand, there are too many imponderables.  
EPA insists that using credible evidence will not "change any 
of the numeric emission limits with which sources must 
comply" and that reference tests remain the benchmark 
against which credible evidence is measured.  Brief of Re-
spondent at 3, 11.  In promulgating the rule, EPA stated that 
credible evidence was "not intended to and will not serve to 
affect the stringency of underlying emission standards by 
amending the nature of the compliance obligation."  62 Fed. 
Reg. at 8315.  It explained:

     Typically, reference test methods ... quantify the pres-
     ence of particular physical attributes--for example, mass 
     or concentration of a chemical or group of chemicals--
     over a specified period of time.  As long as these two 
     elements, quantification and specified time period--are 
     retained and the data from the alternate method is 
     related to the reference test, information generated by 
     alternate methods yield data bearing on what the results 
     of a reference test would have been, and the use of such 
     information to establish compliance or noncompliance in 



     an enforcement action will not affect the stringency of 
     the standard.

62 Fed. Reg. at 8319.  Petitioners dismiss EPA's assertions, 
claiming that the agency "is in denial" about the conse-
quences of its own actions.  Brief of Petitioners at 34.

     Will each of the 130 or so reference tests truly be main-
tained as benchmarks against which credible evidence will be 
measured?  The tests themselves are described in "painstak-
ing technical detail in various appendices throughout Title 40 
C.F.R. chapter I."  Hoburg, supra, at 785.  For all we know, 
application of EPA's credible evidence rule in the place of a 
reference test may potentially affect some standards but not 
others.  Moreover, credible evidence is not a closed set.  
Given the universe of all possible evidence that might be 
considered "credible," it is impossible for us to decide now 
what impact the rule will have.  EPA's representation that 
credible evidence must be "related" to the results a reference 
test would have shown is highly abstruse.  See 62 Fed. Reg. 
8314 (promulgation of credible evidence rule).  An enforce-
ment action brought on the basis of credible evidence would, 
we believe, provide the factual development necessary to 
determine whether the new rule has affected whatever exist-
ing standard is involved.  Until then, we have the "classic 
institutional reason to postpone review:  we need to wait for a 
rule to be applied to see what its effect will be."  Louisiana 
Environmental Action Network, 87 F.3d at 1385 (quoting 
Diamond Shamrock v. Costle, 580 F.2d 670, 674 (D.C. Cir. 
1978)).

     Petitioners cannot point to any great hardship they would 
suffer by our deferring judicial review.  EPA's rule does not 
require them "to engage in, or to refrain from, any conduct."  
Texas v. United States, 118 S. Ct. 1257, 1260 (1998).  Unlike 
the drug manufacturers in Abbott Laboratories, but like the 
cosmetics companies in Toilet Goods Ass'n v. Gardner, 387 
U.S. at 164, petitioners here need not change their behavior 
or risk costly sanctions.  Source owners and operators are 
already under an obligation to comply with EPA's emission 
standards.  If the credible evidence rule has in fact altered 
these standards, petitioners can raise that as a defense in an 



enforcement action.  The burden of participating in future 
proceedings does not "constitute sufficient hardship for the 
purposes of ripeness."  Florida Power & Light Co. v. EPA, 
No. 95-1093, 1998 WL 336520, *8 (D.C. Cir. June 26, 1998).  
To be sure, it is easier and cheaper to mount a single 
challenge now rather than defend a series of enforcement 
actions.  But "this kind of litigation cost-saving" does not 
"justify review in a case that would otherwise be unripe."  
Ohio Forestry Ass'n v. Sierra Club, 118 S. Ct. 1665, 1671 
(1998).

     This brings us to petitioners' contention that the credible 
evidence rule illegally converts "periodic" standards to "con-
tinuous" ones.  Owners and operators of emission sources are 
required, according to petitioners, to meet emission limits 
only when intermittent tests are conducted;  at all other times 
they are subject to no more than a "general duty" require-
ment to maintain good operating procedures.  Brief of Peti-
tioners at 18.

     Again, we find that it would be premature for us to decide 
this issue now.  EPA points to provisions of the Clean Air 
Act and implementing regulations seeming to support its view 
that compliance is required continuously, not periodically.  
Still, the effect of the credible evidence rule on compliance 
obligations is difficult to assess without any information or 
experience showing how the rule operates in particular set-
tings.  For some standards, measuring emission levels at 
each and every instant--i.e., on a continuous basis--might 
affect stringency in ways that are impossible at this moment 
to foretell.  We therefore find this issue unripe for review as 
well.

     Because the merits of petitioners' first set of contentions 
are not justiciable, we do not reach their related assertion, 
also raised by Battery Council International as intervenor, 
that the Clean Air Act Amendments provide no basis for 
promulgating the credible evidence rule.  Petitioners argue 
that s 113(a) of the Act addresses only the initiation of an 
enforcement action.4  Although this is a purely legal question, 

__________
     4  Section 113(a) provides that an action to enforce compliance 
may be brought "[w]henever, on the basis of any information 


and thus presumably ripe, the need for statutory authority 
depends in the first instance on what it is that the credible 
evidence rule actually accomplishes.  See Toilet Goods, 387 
U.S. at 163-64.5

                                     III


     Petitioners also challenge EPA's credible evidence addi-
tions to 40 C.F.R. Part 51 (requirements for the preparation, 
adoption, and submission of state implementation plans) and 
Part 52 (requirements for the approval and promulgation of 
implementation plans), claiming that EPA has "violate[d] the 
Federal-State division of authority established by [s 110 of 
the Act] by requiring States to revise SIPs that EPA has 
found are already adequate to implement the Act."  Brief of 
Petitioners at 28.  EPA's revisions inserted language to the 
effect that the state plans "must not preclude the use, in-
cluding the exclusive use, of any credible evidence or infor-
mation...."  40 C.F.R. s 51.212;  see also id. ss 52.12(c) 
(federal enforcement of state plans), 52.33(a) (compliance 
certifications).  According to petitioners, these changes "ille-
gally invade" the authority of states under the Clean Air 
Act.  Brief of Petitioners at 48.

     During the credible evidence rulemaking, the EPA re-
sponded to comments that these amendments were unautho-
rized by asserting that

__________
available to the Administrator, the Administrator finds that any 
person has violated or is in violation of" an applicable standard.  
Although s 113(a) is written in terms of finding a violation, the 
procedure followed is that the Administrator issues a notice of 
violation and then may either issue an administrative order, 
s 113(d), or commence a civil action, s 113(b).  See 42 U.S.C. 
s 7413.

     5  If, as EPA maintains, the rule really does not change the 
standards, then it might be seen as a permissible exercise of the 
agency's general rulemaking authority under s 301 of the Act, 42 
U.S.C. s 7601(a)(1).  (The agency itself does not rely exclusively on 
ss 113(a) and (e), noting that the credible evidence rulemaking was 
"based primarily on EPA's existing authority prior to the 1990 CAA 
Amendments."  62 Fed. Reg. at 8320.)


     EPA is not by this rulemaking revising any SIP;  rather, 
     EPA is amending the rules governing SIPs.  Such rules 
     are promulgated under EPA's authority to (1) require 
     SIPs to provide adequate enforcement authority (see 
     sections 110(a)(2)(A), (C), and (E));  (2) call for SIP 
     revisions to correct inadequacies (see section 110(k)(5));  
     and (3) "prescribe such regulations as are necessary to 
     carry out [the Administrator's] functions under this chap-
     ter.  42 U.S.C. s 7601.

Response to Comments at 103.  EPA's brief explains that it 
derived its authority for the rule from s 110(a)(2)(H)(ii), 
under which state plans shall "provide for revision" whenever 
EPA finds that the plan is "substantially inadequate to ... 
comply with any additional requirements established under 
this chapter," 42 U.S.C. s 7410(a)(2)(H)(ii), and from the 
statutory requirement that state plans must be "enforceable."  
Brief of Respondent at 41.  This is hard to follow.  If state 
plans approved by EPA met the enforceability requirement 
prior to EPA's adoption of the credible evidence rule, one 
may wonder why the state plans have now become "unen-
forceable" to the extent they do not permit the use of credible 
evidence.  The pre-existing test methods, after all, are still 
available to determine compliance.  In any event the merits 
of this claim are not properly before us. 

     Regardless whether a state might be able to challenge 
directly the revised regulations (no state has), petitioners 
cannot do so.  Nothing in the amended regulations requires 
states to change their implementation plans.  That can only 
occur through an independent procedure known as a "SIP 
call."  Under s 110(k)(5), the EPA must notify a state of 
inadequacies in its plan and request the submission of a 
revised plan.  42 U.S.C. s 7410(k)(5).  This begins an exten-
sive regulatory process that includes the publication of a 
proposed plan in the Federal Register for notice and com-
ment before final approval by the agency.  See Greater 
Cincinnati Chamber of Commerce v. EPA, 879 F.2d 1379 (6th 



Cir. 1989) (finding that SIP calls do not constitute final 
agency action).

     This process was set in motion before the promulgation of 
the rule challenged here.  See 62 Fed. Reg. at 8327.  SIP 
calls to various states were issued as early as 1994.  EPA's 
notice to states included draft credible evidence language 
that, "if adopted by the State and submitted to EPA for 
approval in the SIP, would satisfy the requirements of this 
SIP call."  60 Fed. Reg. 46,222, 46,225 (1995) (approving 
South Dakota's plan);  see also 60 Fed. Reg. 36,361 (1995) 
(Kansas);  62 Fed. Reg. 17,081, 17,082 (1997) (Minnesota).  
When EPA published the credible evidence rule, it noted that 
fifteen states had submitted new plans and several had 
already been approved.  Thus, the request that state plans be 
revised and the submission and approval of revised plans 
were not triggered by the amendments to Parts 51 and 52.  
In this case, petitioners have challenged neither the SIP calls 
nor any of the newly-approved state plans.

     Even if we were to assume that revising the regulations 
forced the states to submit new plans--something not sug-
gested by the record--we would find petitioners' challenge 
unripe.  It is not at all apparent that use of credible evidence 
alters the emissions standards governing petitioners' activi-
ties.  Although the question whether EPA had statutory 
authority is a purely legal one, the effect of the credible 
evidence rule on petitioners--that is, the effect of language in 
state plans specifying that use of credible evidence is not 
precluded--is highly uncertain for reasons already men-
tioned.  In addition, an amicus brief submitted by state air 
pollution authorities indicates that states have historically 
used credible evidence and that some state and local air 
agencies have relied on credible evidence as the exclusive 
basis for enforcement actions.  See Brief of Amici Curiae at 
4-5.  Like the Supreme Court in Toilet Goods, 387 U.S. at 
162, we believe that our judicial appraisal "is likely to stand 
on a much surer footing in the context of a specific application 
of this regulation."  


                                      IV


     Battery Council International, as intervenor, claims that 
EPA has "attempted unlawfully to revise" its permit shield 
regulations in promulgating the credible evidence rule.  Brief 
of Intervenor at 27.

     In the 1990 Amendments, Congress established an operat-
ing permit program for certain sources of air pollution, 
including major stationary sources.  See 42 U.S.C. ss 7661-
7661f.  Under this program, each permit issued must include 
all emissions limitations and standards applicable to the 
source, as well as provisions concerning inspection, monitor-
ing, compliance certification, and reporting requirements.  
The regulations implementing the permit program are con-
tained in 40 C.F.R. Part 70.

     Battery Council thinks the following language in EPA's 
preamble to the credible evidence rule "would undermine the 
principal purpose" of the permits:

     [although permits] can include a "permit shield" protect-
     ing [a source] from allegations that it has failed to satisfy 
     CAA monitoring requirements, such shield does not re-
     lieve the source of its obligation to comply with the 
     underlying emission limits or other applicable require-
     ments being monitored....  In other words, ... the 
     source would not be shielded from allegations of noncom-
     pliance with the underlying substantive requirements 
     (e.g., emission limits) being monitored even if the 
     source's required monitoring failed to detect the viola-
     tion.

62 Fed. Reg. at 8320.  Battery Council argues that, contrary 
to EPA's interpretation, "permit shields also protect sources 
from enforcement of 'underlying emission limits,' as long as 
sources comply with their permits."  Brief of Intervenor at 
30.

     We will not reach the merits of this argument.  The 
credible evidence rule did not change any language in Part 



70.  It is doubtful that the preamble alone is definite and 
specific enough to be a binding statement of agency policy.  
For one thing, the statements concerning the permit shield 
were not published in the Code of Federal Regulations.  See 
Florida Power & Light, 1998 WL 336520, *4.  For another, 
EPA has claimed that its statements were no more than "an 
interpretation" given "existing permit shield regulation," 
Brief of Respondent at 45, and Battery Council has presented 
no evidence that the preamble has a direct and immediate 
effect on it.  In Kennecott Utah Copper Corp. v. Department 
of the Interior, 88 F.3d 1191, 1222 (D.C. Cir. 1996), we held 
that although a "preamble may under some circumstances be 
reviewable," the preamble challenged there was nevertheless 
not ripe because the issue presented was conjectural and "a 
more complete understanding of its ramifications must await 
a concrete application."  The same holds true here.  This 
challenge is therefore unripe for review.

                                  *   *   *


     Petitioners and intervenor raise a number of other subsid-
iary issues which, while we have considered fully, present no 
need for discussion.  For the reasons stated above, we dis-
miss the petition for review.

                                                                             So ordered.




              
