United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued October 8, 2008 Decided March 20, 2009

No. 07-1151

NATURAL RESOURCES DEFENSE COUNCIL,

PETITIONER

v.

ENVIRONMENTAL PROTECTION AGENCY,

RESPONDENT

AMERICAN FARM BUREAU FEDERATION, ET AL.,

INTERVENORS

Consolidated with 08-1057

On Petitions for Review of Final Actions 

of the Environmental Protection Agency

Colin C. O'Brien argued the cause for petitioner. With him

on the briefs was John Walke. 

Joshua M. Levin, Attorney, U.S. Department of Justice,

argued the cause for respondent. With him on the brief was

John C. Cruden, Deputy Assistant Attorney General.

Peter S. Glaser argued the cause for intervenor. With him
2

on the brief were Norman W. Fichthorn, Julie Anna Potts, and

Harold P. Quinn Jr. Richard E. Schwartz entered an

appearance.

Before: HENDERSON, RANDOLPH and ROGERS, Circuit

Judges.

Opinion for the Court filed by Circuit Judge RANDOLPH.

Opinion concurring in part and dissenting in part filed by

Circuit Judge ROGERS.

RANDOLPH, Circuit Judge: State authorities submit air

pollution emissions data to the Environmental Protection

Agency. EPA monitors the data in order to evaluate regional

compliance with national air pollution standards. In 2007, EPA

promulgated a regulation governing the exclusion of emissions

data during “exceptional events” such as natural disasters. The

Natural Resources Defense Council (NRDC) brought petitions

for review, seeking to set aside the rule’s definition of “natural

events” and to vacate several statements in the preamble to the

rule concerning types of events that may qualify as

“exceptional.” 

I.

The Clean Air Act commands EPA to promulgate national

air quality standards for certain air pollutants. States develop

and implement plans to comply with EPA’s air quality

standards. 42 U.S.C. §§ 7408–7410. The states have

established a network of air quality monitoring stations to

measure regional compliance with EPA’s national standards.

Based on this data, EPA designates areas as being in either

“attainment” or “nonattainment” and imposes more rigorous
3

pollution control measures in “nonattainment” areas. See 42

U.S.C. §§ 7407(d), 7502. 

In 2005, Congress amended the Clean Air Act to require

EPA to promulgate regulations governing air quality monitoring

during “exceptional events.” See 42 U.S.C. § 7619(b). The

amended statute defined “exceptional event” as an event that “(i)

affects air quality; (ii) is not reasonably controllable or

preventable; (iii) is an event caused by human activity that is

unlikely to recur at a particular location or a natural event; and

(iv) is determined by the Administrator . . . to be an exceptional

event.” Id. § 7619(b)(1)(A). EPA published a final exceptional

events rule, accompanied by a lengthy preamble, in March 2007.

Treatment of Data Influenced by Exceptional Events, 72 Fed.

Reg. 13,560 (Mar. 22, 2007) (codified at 40 C.F.R. §§ 50.1,

50.14, 51.930). The final rule’s definition of “exceptional

events,” codified at 40 C.F.R. § 50.1(j), repeated the statutory

language. In the next subsection, the rule defined “natural

event” – as used in 42 U.S.C. § 7619(b)(1)(A)(iii) – as “an event

in which human activity plays little or no direct causal role.” 40

C.F.R. § 50.1(k). The rule also provided that states may “flag”

anomalous data caused by exceptional events, and that EPA will

then review the flagged data and determine whether to exclude

it from the set of data used in reviewing compliance with its air

quality standards. 40 C.F.R. § 50.14.

NRDC argues against EPA’s definition of “natural event,”

against its description in the rule’s preamble of a “final rule

concerning high wind events,” and against its list, again in the

preamble, of examples of potentially exceptional events. 

II.

NRDC’s complaint is that EPA should not have defined

“natural event” in 40 C.F.R. § 50.1(k) to include events in which
4

human activities play “little” causal role. As NRDC sees it, a

“natural event” within the meaning of § 7619 is something that

occurs without the slightest human influence. EPA says this

objection was never raised during the rulemaking and is

therefore barred. 

Section 307 of the Clean Air Act states: “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. § 7607(d)(7)(B). Similar provisions are common with

respect to other agencies. See Wash. Ass’n for Television &

Children v. FCC, 712 F.2d 677, 682 n.6 (D.C. Cir. 1983). Their

purpose is to ensure that the agency and other interested persons

have been alerted to the commenter’s objection to the proposed

rule. The agency then may correct or modify the rule it

proposed or explain why it disagrees with the objection. See

Motor & Equip. Mfrs. Ass’n v. Nichols, 142 F.3d 449, 462 (D.C.

Cir. 1998). Other parties also may contribute to the agency’s

deliberations by endorsing or opposing the objection and by

providing information and arguments in support of their

position. 

NRDC thinks the following portion of its nine-page, single

spaced letter to EPA constituted an objection to EPA’s proposed

definition of “natural event”: 

Under no circumstance can the clean-up

associated with a natural disaster itself be considered a

“natural event.” EPA’s suggestion to the contrary flies

in the face of the plain statutory language. The statute

clearly and explicitly distinguishes between “natural

event[s]” (events that do not have a human origin) and

“events caused by human activity.” A natural event is

one that is not the result of human activity . . . While the
5

level of human activity that discharges pollutants may

increase in the wake of a natural disaster, emissions

from clean-up activities (such as debris burning,

operation of diesel equipment, and demolition activities)

are clearly events caused by human activity, and may

not be classified as “exceptional events” unless they

meet each of the requirements of section 319 for

qualifying anthropogenic events.

In short, the activities themselves that are

responsible for the emissions (and possible violations of

the NAAQS) are of human origin, and by definition not

natural events. The fact that a natural event precipitates

the need for human activity cannot and does not

transform the human activity itself into a natural event.

Thus, the Act clearly precludes EPA from identifying

emissions from clean-up activities as “natural events”

that qualify as exceptional events.

NRDC Comments, at 4–5. 

Given the context, no EPA official would have guessed that

NRDC was complaining about the agency’s proposed definition

of “natural event.” Those familiar with the proceedings would

have taken NRDC’s remarks as a criticism of the one sentence

in the notice of proposed rulemaking dealing with clean-up

activities after a natural disaster (such as the eruption of Mt. St.

Helens in 1980 or Hurricane Katrina in 2005). The sentence

read: “For the purpose of flagging, major natural disasters, such

as hurricanes and tornadoes for which State, local, or Federal

relief has been granted, and clean-up activities associated with

these events may be considered exceptional events.” Treatment

of Data Influenced by Exceptional Events, 71 Fed. Reg. 12,592,

12,596 (Mar. 10, 2006). It is not apparent that EPA even rested

its view about clean-up activities on the proposed definition of
6

“natural event” in 40 C.F.R. § 50.1(k) rather than on the clause

in another proposed subsection defining “exceptional events” to

include human activities “unlikely to recur at a particular

location,” id. § 50.1(j). 

There are additional reasons why NRDC’s critique, quoted

above, would not have alerted the careful reader to the

complaint it now makes about § 50.1(k). NRDC’s comments

said that a natural event could not have a “human origin” and

could not be “the result of human activity.” These comments

are not necessarily inconsistent with § 50.1(k)’s definition of

natural events as ones in which human activity plays “little or no

direct causal role.” No one would say that the “origin” of the

tornado was human activity because the storm spread man-made

air pollutants throughout the countryside. The definition of

“natural event” in proposed § 50.1(k) was only a few words

long, yet NRDC did not quote the portion it now finds

objectionable. NRDC never even identified the rule by section

number or placement in the notice of proposed rulemaking. We

have held that Section 307 of the Clean Air Act bars litigants

from arguing against a particular section of a rule on judicial

review if they failed to identify the particular section in their

comments during the rulemaking. See Mossville Envtl. Action

Now v. EPA, 370 F.3d 1232, 1240 (D.C. Cir. 2004); Motor &

Equip. Mfrs., 142 F.3d at 462. A citation to the section of the

rule or a description of it may be all that is needed. If a

comment lacking even that low level of specificity sufficed, the

agency would be subjected to verbal traps. Whenever the

agency failed to detect an obscure criticism of one aspect of its

proposal, the petitioner could claim not only that it had complied

with Section 307 but also that the agency acted arbitrarily

because it never responded to the comment. Rulemaking

proceedings and the legal doctrines that have grown up around

them are intricate and cumbersome enough. Agency officials

should not have to wade through reams of documents searching
7

for “‘implied’ challenges.” Mossville, 370 F.3d at 1239. It is

not too much to expect interested persons to point to the

particular portion of the proposed rule they are arguing against.

It is worth adding that after EPA promulgated the final rule

containing § 50.1(k) and its definition of “natural event,” NRDC

filed a petition for reconsideration. In its petition NRDC spelled

out for the first time its complaint about not excluding from

“natural event” those events in which human activity had only

a “little” causal effect. NRDC also explained that the grounds

for its objection to § 50.1(k) “arose after the period for public

comment and are of central relevance to the rule.” Petition for

Reconsideration, In the Matter of the Final Rule: Treatment of

Data Influence by Exceptional Events, No. 2060-AN40 (E.P.A.

May 21, 2007). This representation cuts against NRDC’s

current position that it objected to § 50.1(k) during the comment

period and is a further indication that NRDC failed to satisfy

Section 307’s requirement. 

III.

The balance of NRDC’s case deals not with the rules EPA

promulgated but with its statements in the preamble to the rules.

We have jurisdiction to review these statements only if they

constitute final agency action. 42 U.S.C. § 7607(b)(1). A final

agency action is one that marks the consummation of the

agency’s decisionmaking process and that establishes rights and

obligations or creates binding legal consequences. Bennett v.

Spear, 520 U.S. 154, 177–78 (1997). While preamble

statements may in some unique cases constitute binding, final

agency action susceptible to judicial review, Kennecott Utah

Copper Corp. v. Dep’t of Interior, 88 F.3d 1191, 1222–23 (D.C.

Cir. 1996), this is not the norm. Agency statements “having

general applicability and legal effect” are to be published in the

Code of Federal Regulations. Federal Register Act, 44 U.S.C.
8

§ 1510(a)–(b); 1 C.F.R. § 8.1; see Brock v. Cathedral Bluffs

Shale Oil Co., 796 F.2d 533, 539 (D.C. Cir. 1986). 

In one section of the preamble, EPA refers to its “final rule

concerning high wind events,” which “states that ambient

particulate matter concentrations due to dust being raised by

unusually high winds will be treated as due to uncontrollable

natural events” when certain conditions apply. 72 Fed. Reg.

13,560, 13,576. There is no such final rule. The final rule does

not mention high wind events or anything about “ambient

particulate matter concentrations.” EPA calls this a drafting

error. In light of the error, the high wind events section of the

preamble is a legal nullity. Agencies must publish substantive

rules in the Federal Register to give them effect. 5 U.S.C.

§ 552(a)(1); Morton v. Ruiz, 415 U.S. 199, 233 & n.27 (1974).

An unpublished final rule on high winds can have no legal

consequences, and neither can preamble statements mentioning

such a rule. See Brock, 796 F.2d at 539. Because there was no

“nationally applicable . . . final action taken” by EPA, 42 U.S.C.

§ 7607(b)(1), there is nothing for this court to review. 

The preamble also contains a list of “examples” of events

that may be considered “exceptional” under the final rule. See

72 Fed. Reg. 13,560, 13,564–65. NRDC objects to these

examples on the basis that they treat a variety of common events

as per se exceptional in violation of 42 U.S.C. § 7619. We do

not believe the statements in the preamble amounted to final

agency action. EPA spoke in the conditional, suggesting that

events in the various categories “may be exceptional events” or

“may qualify for exclusion under this rule provided that all other

requirements of the rule are met.” 72 Fed. Reg. at 13,564–65.

Other statements were equivocal, such as the declaration,

repeated several times in different forms, that certain events are

to be evaluated “on a case-to-case basis.” Id. Giving “decisive

weight to the agency’s choice between ‘may’ and ‘will,’” Brock,
9

796 F.2d at 538, we have held that similar statements are

nonbinding and unreviewable. See Interstate Natural Gas Ass’n

of Am. v. FERC, 285 F.3d 18, 60 (D.C. Cir. 2002); Appalachian

Power Co. v. EPA, 208 F.3d 1015, 1023 (D.C. Cir. 2000). 

Even if the statements in the preamble were reviewable

under the Clean Air Act, they are not ripe for review at this time.

The statements about exceptional events are “hypothetical and

non-specific.” Kennecott, 88 F.3d at 1223. NRDC has not

demonstrated that any of the statements has immediate legal or

practical consequences. How EPA will use or rely on or

interpret what it said in the preamble is uncertain. See

Kennecott, 88 F.3d at 1223; Pub. Citizen, Inc. v. U.S. Nuclear

Regulatory Comm’n, 940 F.2d 679, 683 (D.C. Cir. 1991). We

can see no significant hardship to the parties from waiting for a

real case to emerge. As EPA points out in its brief, the Clean

Air Act “provides for judicial review of any EPA decision to

determine the attainment status of an area, or to designate or

redesignate an area, based on EPA’s decision to exclude

exceptional events data or other information.” Resp’ts Br. at 39;

cf. Clean Air Implementation Project v. EPA, 150 F.3d 1200,

1204 (D.C. Cir. 1998).

The petitions for review are therefore dismissed. 

So ordered.
1

 The Clean Air Act defines “exceptional event” as an event

that —

(i) affects air quality;

(ii) is not reasonably controllable or preventable;

(iii) is an event caused by human activity that is unlikely to

recur at a particular location or a natural event; and

(iv) is determined by the Administrator through the process

established in the regulations promulgated under paragraph (2)

to be an exceptional event.

42 U.S.C. § 7619(b)(1)(A) (emphasis added).

ROGERS, Circuit Judge, concurring in part and dissenting in

part: When an agency receives comments that object to its

application of a statutory term as being contrary to the plain text

of the statute, what is the agency to understand is the target of

the objection? The specific application or the agency’s

underlying interpretation of the term or both? The court

responds only the application. But the answer depends on how

the comments are phrased. If, as here, the comments address a

specific application by pointing out that it reflects an

interpretation of a statutory term that contradicts the plain text

of the statute, how can the agency respond to the comments

without considering whether its definition is consistent with the

statute, much less how would it not be on notice that the

comments extended to the agency’s interpretation of the

statutory term? 

The NRDC objected to EPA’s interpretation of the term

“natural event,” 42 U.S.C. § 7619(b)(1)(A)(iii),1

 as applied to

emissions arising from clean-up activities associated with

natural disasters, explaining that such an interpretation was

inconsistent with the statutory text and the legislative history.

It offered these comments in the context of addressing EPA’s

list of examples of “natural events” in the preamble to the notice

of proposed rulemaking, The Treatment of Data Influenced by
2

Exceptional Events (“NPRM”), 71 Fed. Reg. 12,592, 12,596

(Mar. 10, 2006). NRDC Comments, at 4-5. Given the stated

reason for the objection to the application and the context, it is

unclear what rule follows from the court’s approach for there is

no heightened comment requirement under the Administrative

Procedure Act, the Clean Air Act, or our precedent.

Although section 307’s exhaustion requirement is “strictly”

enforced, Motor & Equip. Mfrs. Ass’n v. Nichols, 142 F.3d 449,

462 (D.C. Cir. 1998), our precedent explains that “commenters

must be given some leeway in developing their argument before

this court, so long as the comments to the agency were adequate

notification of the general substance of the complaint.” S. Coast

Air Quality Mgmt. Dist. v. EPA, 472 F.3d 882, 891 (D.C. Cir.

2006). Likewise, our precedent rejects the idea that the

exhaustion requirement calls for hair-splitting. E.g.,

Appalachian Power Co. v. EPA, 135 F.3d 791, 817 (D.C. Cir.

1998). For example, in National Petrochemical & Refiners

Association v. EPA, 287 F.3d 1130 (D.C. Cir. 2002), the court

concluded that although the comments did not specifically

mention the cold-start portion of the Federal Test Procedure,

they did “raise the underlying issue of poor performance at

certain temperatures,” id. at 1139, and consequently the

comments were “close enough to have put the EPA on notice

that it had to defend the performance of the NOx adsorbers at all

relevant temperatures and conditions,” id. at 1139-40. So too

here, where the comments and the structure of the NPRM both

indicate that EPA was put on notice of NRDC’s underlying

objection to the definition of “natural event.” 

The comments at issue stated:

 [1] Under no circumstances can the clean-up

associated with a natural disaster itself be considered

a “natural event.” [2] EPA’s suggestion to the contrary
3

flies in the face of the plain statutory language. [3] The

statute clearly and explicitly distinguishes between

“natural event[s]” (events that do have a human origin)

and “events caused by human activity.” [4] A natural

event is one that is not the result of human activity. [5]

For example, the Legislative History identifies only

forest fires and volcanic eruptions as examples of

natural events. [6] While the level of human activity

that discharges pollutants may increase in the wake of

a natural disaster, emissions from clean-up activities

(such as debris burning, operation of diesel equipment,

and demolition activities) are clearly events caused by

human activity, and may not be classified as

“exceptional events” unless they meet each of the

requirements of section 319 for qualifying

anthropogenic events.

 [7] In short, the activities themselves that are

responsible for the emissions (and possible violations

of NAAQS) are of human origin, and by definition not

natural events. [8] The fact that a natural event

precipitates the need for human activity cannot and

does not transform the human activity itself into a

natural event. [9] Thus, the Act clearly precludes EPA

from identifying emissions from clean-up activities as

“natural events” that qualify as exceptional events.

NRDC Comments, at 4-5 (internal citation omitted) (alteration

other than numbering in NRDC comments).

It is readily apparent these comments put EPA on notice

that the NRDC was objecting to its broad interpretation of the

statutory term “natural event.” Although the comments do not

expressly refer to 40 C.F.R. § 50.1(k), which codifies EPA’s

definition of “natural event,” the introductory phrase — “[u]nder
4

no circumstances” — signals an underlying concern with EPA’s

interpretation of what can qualify as a “natural event.” So

introduced, the second sentence makes clear that the preceding

reference to a particular application is grounded in an objection

to the agency’s interpretation of what is a “natural event” as too

broad and contrary to the plain statutory text. The third sentence

explains why, pointing to the distinction in the statute between

natural events and those caused by human activity. See 42

U.S.C. § 7619(b)(1)(A)(iii). The fourth sentence states the

conclusion that follows in the commenter’s view. Support for

that view is offered in the fifth sentence’s reference to an

illustrative example in the legislative history. The sixth

sentence identifies the confusion that the agency’s broad

interpretation reflects, given the statutory distinction and

inclusion of specific exceptions. The second paragraph makes

the same point: the statute bars EPA from including such an

application in its listing of examples of a “natural event”

because clean-up activities and other events resulting from

human activity are inherently (as opposed to impliedly) human

activities and thus not a “natural event.” 

Even if the entirety of the above-quoted comments did not

put EPA on notice that the NRDC was objecting to its

interpretation of “natural event,” the fourth sentence did.

Following a sentence noting the statutory distinction, the fourth

sentence states: “A natural event is one that is not the result of

human activity.” [3-5] This alone was fair warning that,

according to the NRDC, the statute precludes treating any

human-caused activity as a “natural event.” As the fourth

sentence was made in the context of addressing EPA’s

application of its definition, the comments were “close enough,”

Nat’l Petrochem. & Refiners Ass’n, 135 F.3d at 817, to have put

EPA on notice that the commenter was challenging the agency’s

definition of a statutory term. Either way EPA could not avoid

being aware that the NRDC’s comments objected to the
5

underlying broad interpretation of “natural event” and so met the

Clean Air Act’s “reasonable specificity” requirement, 42 U.S.C.

§ 7607(d)(7)(B). 

This is not an instance in which the agency would be

unclear as to what the comments addressed or have to “wade

through reams of documents searching for ‘implied

challenges,’” Op. at 6-7 (quoting Mossville Envtl. Action Now

v. EPA, 370 F.3d 1232, 1240 (D.C. Cir. 2004)). The comments

state on the first page that they are addressing “elements of

EPA’s March 10 proposal,” i.e., the NPRM, and explain why,

as demonstrated by one example in the preamble’s listing of

examples, EPA’s interpretation of “natural event” could not be

consistent with the plain meaning of the statute, see Op. at 6,

pointing to the statutory text and the legislative history, [3]-[5].

Even speculating — contrary to EPA’s proposal, see NPRM, 71

Fed. Reg. at 12,596 — that EPA’s view of clean-up activities

was based on the definition of “exceptional events” as including

human activities “unlikely to recur at a particular location,” see

Op. at 5-6, the comments would alert EPA to the objection that

the statute does not permit an activity with any human cause to

be an “exceptional event” unless the statutory criteria for an

“event caused by human activity” were satisfied, [6]. In fact, by

using separate sections and headings in the comments to address

each possibility, NRDC’s comments object to the proposed

rule’s treatment of clean-up activities as “exceptional events”

either as natural events or events caused by human activity. 

The specified context of the comments, especially the

placement of the clean-up-activities example in that part of the

NPRM where EPA was giving examples of how its definition

of “natural event” would be applied also shows that EPA was on

notice of the objection to its interpretation of “natural event.”

The comments address a sentence in the NPRM involving

clean-up activities after a natural disaster, see Op. at 5, that
6

2

 In seeking reconsideration of the final rule, NRDC stated:

The Final Rule’s interpretation of the statutory term

“natural event” is an unlawful departure from the clear

language of the statute. The statute identifies a dichotomy

whereby events are either “natural” or “caused by human

activity”. 42 U.S.C. § 7619(1)(A). Since the statute (and

logic) does not permit an event to be both natural and caused

by human activity, a ‘natural event” has no human activity.

Petition for Reconsideration of the Natural Resources Defense

Council, In the Matter of the Final Rule: Treatment of Data Influenced

by Exceptional Events, No. 2060-AN40, at 5-6 (E.P.A. May 21,

2007).

appears in the section of the preamble to the proposed rule

giving examples of “natural events.” NPRM, 71 Fed. Reg. at

12,596 (“5. Natural Events”). The comments thereby direct the

reader to the underlying concept that is at issue: a broad

interpretation of “natural event” that includes activities with

some human contribution. Together, the text and structure of

the comments and placement of the clean-up activities example

in the NPRM’s listing sufficed to put EPA on notice that the

NRDC was objecting to EPA’s definition of “natural event.”

Nothing in the NRDC’s petition for reconsideration suggests its

earlier comments had not raised an objection to the agency’s

interpretation of “natural event.” See Op. at 7. In the petition

the NRDC complains only that earlier comments could not have

objected to justifications for the definition that appeared for the

first time in the preamble to the final rule, namely certain

legislative history, a previous rulemaking proposal, and new

illustrative examples. In any event, the rehearing objection to

EPA’s definition of “natural event” tracks the NRDC’s earlier

comments.2

Nonetheless, although EPA was on notice that the NRDC
7

was objecting to its broad interpretation of “natural event” in a

manner that would include human activities, the NRDC’s

objection fails on the merits. The Clean Air Act does not define

“natural event” or specify how to categorize events with

predominantly natural causes but some human contribution.

Because the statute leaves a gap to be filled by EPA, the

statutory term is ambiguous. EPA’s definition, in turn, is

permissible. See Chevron U.S.A., Inc. v. Natural Resources

Defense Council, 467 U.S. 837, 842-43 (1984). As EPA offers,

“human activities sometimes contribute to otherwise

spontaneous events,” Respondent’s Br. at 33; see also

Treatment of Data Influenced by Exceptional Events (“Final

Rule”), 72 Fed. Reg. 13,560, 13,563 (Mar. 22, 2007), such as a

planned forest fire that gets out of control because of unforeseen

circumstances. Still, the question whether EPA’s application of

the term “natural event” to particular circumstances will, in fact,

be permissible is for another day, as EPA’s listing of examples

is neither exhaustive, see Final Rule, 72 Fed. Reg. at 13,564,

nor binding on it, see Op. at 8-9; cf. Cement Kiln Recycling

Coal. v. EPA, 493 F.3d 207, 226-28 (D.C. Cir. 2007); Interstate

Natural Gas Ass’n of America v. FERC, 285 F.3d 18, 60 (D.C.

Cir. 2002). 

Accordingly, I respectfully dissent from Part II of the

opinion and otherwise concur.