Case 1:10-cv-00985-HHK Document 25 Filed 07/05/11 Page 1 of 19 

UNITED STATES DISTRICT COURT 

FOR THE DISTRICT OF COLUMBIA

CENTER FOR BIOLOGICAL 

DIVERSITY, et al., 

Plaintiffs, 

v.
 

UNITED STATES ENVIRONMENTAL
 

PROTECTION AGENCY, Civil Action 10-00985 (HHK) 

and 

LISA JACKSON, Administrator of the 

Environmental Protection Agency,
 

Defendants.
 

MEMORANDUM OPINION AND ORDER 

Plaintiffs Center for Biological Diversity, Center for Food Safety, Friends of the Earth, 

International Center for Technology Assessment, and Oceana (collectively, “plaintiffs”) bring 

this action against the U.S. Environmental Protection Agency and its Administrator, Lisa Jackson 

(together, “EPA”), seeking to compel agency action with regard to the regulation of emissions by 

nonroad vehicles and engines, including marine vessels and aircraft, under the Clean Air Act 

(“the Act”), 42 U.S.C. § 7401 et seq. Before the Court is EPA’s motion to dismiss in part [#9], 

which argues that three of plaintiffs’ four claims fail to state a claim for relief and are beyond the 

Court’s jurisdiction. Upon consideration of the motion, the opposition thereto, and the record of 

this case, the Court concludes that the motion must be granted in part and denied in part. 
Case 1:10-cv-00985-HHK Document 25 Filed 07/05/11 Page 2 of 19 

I. BACKGROUND 

A. The Clean Air Act 

The Clean Air Act gives EPA the authority to regulate “air pollutants,” a category that it 

defines very broadly. See 42 U.S.C. § 7602(g); Massachusetts v. EPA, 549 U.S. 497, 506–09 

(2007) (describing the history of the Act and efforts to address climate change). Here, plaintiffs’ 

claims relate to two of the Act’s air-quality provisions: section 213 and section 231. Section 213 

deals with emissions from nonroad engines and vehicles, and provides in part that “[i]f the [EPA] 

Administrator determines that any emissions . . . from new nonroad engines or vehicles 

significantly contribute to air pollution which may reasonably be anticipated to endanger public 

health or welfare, the Administrator may promulgate (and from time to time revise) such 

regulations as the Administrator deems appropriate . . . .” 42 U.S.C. § 7547(a)(4). Section 231 

provides in relevant part that EPA “shall, from time to time, issue proposed emission standards 

applicable to the emission of any air pollutant from any class or classes of aircraft engines which 

in [its] judgment causes, or contributes to, air pollution which may reasonably be anticipated to 

endanger public health or welfare.” Id. § 7571(a)(2)(A). These determinations that certain 

emissions cause or contribute to dangerous air pollution are commonly referred to as 

endangerment findings. 

B. Plaintiffs’ Petitions and this Suit 

Between October 2007 and January 2008, plaintiffs submitted three petitions to EPA, 

asking it to use its authority under the provisions described above to regulate greenhouse gas 

emissions from marine vessels, aircraft, and other nonroad vehicles. Compl. ¶¶ 48–50. EPA 

subsequently issued an Advance Notice of Proposed Rulemaking regarding greenhouse gas 

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emissions, see Regulating Greenhouse Gas Emissions Under the Clean Air Act, 73 Fed. Reg. 

44,354 (July 30, 2008), but plaintiffs assert that it was not responsive to their petitions because it 

neither determined whether greenhouse gas emissions from these sources endanger public health 

or welfare nor established a plan for regulating such emissions. Compl. ¶¶ 55–59. Accordingly, 

as required by the Act, see 42 U.S.C. § 7604(a), plaintiffs sent letters to EPA announcing their 

intention to file suit, see Def.’s Mem. Ex. A (“Earthjustice Notice Letter”), Ex. B (“WELC 

Notice Letter”), and then commenced this action.1 

Plaintiffs’ complaint presents four claims under 42 U.S.C. § 7604(a), which allows 

district courts “to compel . . . agency action unreasonably delayed,” each alleging a specific 

unreasonable delay on the part of EPA: (1) failure to respond to plaintiffs’ October 2007, 

December 2007, and January 2008 petitions, Compl. ¶¶ 70–71; (2) failure to determine whether 

emissions of greenhouse gases and black carbon from marine vessels cause or contribute to 

dangerous air pollution, Compl. ¶¶ 72–74; (3) failure to determine whether emissions of 

greenhouse gases and black carbon from nonroad vehicles and engines cause or contribute to 

dangerous air pollution, Compl. ¶¶ 75–77; and (4) failure to determine whether emissions of 

greenhouse gases and black carbon from aircraft engines cause or contribute to dangerous air 

pollution. Compl. ¶¶ 78–80. EPA now moves to dismiss claims two, three, and four. 

1 After plaintiffs filed suit, two aircraft industry groups sought leave to intervene in 

support of EPA. See Ctr. for Biological Diversity v. U.S. EPA, 2011 WL 1346965, at *2 (D.D.C. 

Apr. 11, 2011). The Court denied their motions, finding that they lacked the standing required 

for intervention as of right, id. at *2–7, and that they had not shown a basis for permissive 

intervention. Id. at *7–8. 

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II. LEGAL STANDARDS 

A. Lack of Subject-Matter Jurisdiction 

Under Federal Rule of Civil Procedure 12(b)(1), a defendant may move to dismiss a 

complaint, or a portion thereof, for lack of subject-matter jurisdiction. FED. R. CIV. P. 12(b)(1); 

see Kokkonen v. Guardian Life Ins. Co. of Am., 511 U.S. 375, 377 (1994) (“Federal courts are 

courts of limited jurisdiction. . . . It is to be presumed that a cause lies outside this limited 

jurisdiction . . . .”). In response to such a motion, the plaintiff must establish that the Court has 

subject-matter jurisdiction over the claims in the complaint. See Shuler v. United States, 531 

F.3d 930, 932 (D.C. Cir. 2008). If the plaintiff is unable to do so, the Court must dismiss the 

action. Steel Co. v. Citizens for a Better Env’t, 523 U.S. 83, 94 (1998) (citing Ex parte 

McCardle, 74 U.S. 506, 514 (1868)). When resolving a motion made under Rule 12(b)(1), a 

court may consider material beyond the allegations in the plaintiff’s complaint. Jerome Stevens 

Pharm., Inc. v. FDA, 402 F.3d 1249, 1253–54 (D.C. Cir. 2005). 

B. Failure to State a Claim Upon Which Relief May Be Granted 

On a motion to dismiss for failure to state a claim upon which relief can be granted 

pursuant to Rule 12(b)(6), the Court will dismiss a complaint, or a portion thereof, that fails to 

plead “enough facts to state a claim for relief that is plausible on its face.” Bell Atl. Corp. v. 

Twombly, 550 U.S. 544, 570 (2007). Thus, although a complaint need not contain detailed 

factual allegations, it must recite facts sufficient to at least “raise a right to relief above the 

speculative level . . . on the assumption that all the allegations in the complaint are true (even if 

doubtful in fact).” Id. at 555. A “pleading that offers ‘labels and conclusions’ or ‘a formulaic 

recitation of the elements of a cause of action will not do.’” Ashcroft v. Iqbal, —U.S.—, 129 S. 

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Ct. 1937, 1949 (2009) (quoting Twombly, 550 U.S. at 555). “Nor does a complaint suffice if it 

tenders ‘naked assertion[s]’ devoid of ‘further factual enhancement.’” Id. (quoting Twombly, 550 

U.S. at 557) (alterations in original). At bottom, a complaint must contain sufficient factual 

matter that, accepted as true, would allow the Court “to draw the reasonable inference that the 

defendant is liable for the misconduct alleged.” Id. 

III. ANALYSIS 

EPA seeks the dismissal of claims two, three, and four (which the Court will call the 

“determination claims”) on two grounds: first, that plaintiffs’ notice of intent to sue encompassed 

only claim one and not the remaining claims; and second, that plaintiffs have not identified an 

enforceable obligation that EPA has failed to meet. Because EPA’s notice argument goes to the 

Court’s jurisdiction, the Court addresses it first. See Steel Co., 523 U.S. at 94–95. 

A. Notice of Intent to Sue 

The Act’s “citizen suit” provision, 42 U.S.C. § 7604, provides that the “district courts of 

the United States shall have jurisdiction to compel . . . agency action unreasonably delayed.” Id. 

§ 7604(a). It also provides that, “[i]n any such action for unreasonable delay, notice to the [EPA] 

shall be provided 180 days before commencing such action.” Id. Notice-and-delay requirements 

of this type are “mandatory conditions precedent to commencing suit.” Hallstrom v. Tillamook 

Cnty., 493 U.S. 20, 31 (1989) (construing near-identical language in the Resource Conservation 

and Recovery Act of 1976, 42 U.S.C. § 6972). When suit is filed against a government agency, 

these requirements are, as conditions on the government’s waiver of sovereign immunity, 

jurisdictional. Conservation Force v. Salazar, 715 F. Supp. 2d 99, 102–03 (D.D.C. 2010); see 

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Hercules Inc. v. United States, 516 U.S. 417, 422 (1996) (“[T]he terms of [the government’s] 

consent to be sued in any court define that court’s jurisdiction to entertain the suit.” (quoting 

United States v. Testan, 424 U.S. 392, 399 (1976)) (internal quotation marks omitted)). 

Here, EPA contends that plaintiffs’ notices of intent to sue announced only their intention 

to challenge EPA’s failure to respond to their petitions, and not also its failure to reach the 

endangerment findings sought by those petitions. EPA thus argues that the Court has no 

jurisdiction over claims two, three, and four, which relate to those findings. Plaintiffs respond 

that the notices adequately broadcast their intention to file all of the claims in this action. The 

Court agrees with plaintiffs. 

The Act itself does not define or qualify the term “notice.” See 42 U.S.C. § 7604. EPA’s 

regulations require a notice of intent to sue under the Act to “identify the provisions of the Act 

which requires [the act or duty alleged, and] . . . describe with reasonable specificity the action 

taken or not taken by the Administrator which is claimed to constitute a failure to perform such 

act or duty.” 40 C.F.R. § 54.3(a). Here, plaintiffs have done both. 

Plaintiffs’ notice came in the form of two letters sent to EPA on July 31, 2008. See 

Earthjustice Notice Letter; WELC Notice Letter. The first letter described plaintiffs’ October 

2007 marine-vessels petition and their December 2007 aircraft petition, noted EPA’s failure to 

act thereon, and stated: “We intend to file suit for an unreasonable delay in responding to both 

the marine vessels petition and the aircraft petition should EPA not grant or deny our request 

within 180 days of this notice.” Earthjustice Notice Letter at 2. The remaining four pages of the 

letter discussed EPA’s obligations under sections 213 and 231 of the Act to conduct the 

endangerment determinations requested in the petitions. See Earthjustice Notice Letter at 3–6. 

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Significantly, sections 213 and 231 do not require EPA to respond to petitions — they impose the 

putative endangerment-finding obligations that plaintiffs’ determination claims are intended to 

enforce. See 42 U.S.C. §§ 7547, 7571. A reasonable reader of this letter could not understand 

plaintiffs to challenge only EPA’s failure to make some response to their petitions; such a 

conclusion is inconsistent with the letter’s emphasis on EPA’s alleged statutory obligations to 

make endangerment findings and its description of the dangers posed by climate change. See 

Earthjustice Notice Letter at 3–6. 

The second letter was even clearer. It first described the January 2008 nonroad-emissions 

petition, observed that EPA had not acted thereon, and then announced plaintiffs’ intent to sue. 

WELC Notice Letter at 1–2. It then stated: 

Where, as here, the notice of intent is based on EPA’s failure to act, the notice must 

identify the provisions of the [Act] that require the agency to take action and 

describe the agency’s failure to perform. Section 213 of the [Act] applies to nonroad 

vehicles and engines. Section 213(a)(l), directs EPA ‘to determine if . . . emissions 

[from nonroad engines and vehicles] cause, or significantly contribute to, air 

pollution which may reasonably be anticipated to endanger public health or welfare.’ 

WELC Notice Letter at 2 (omission and third alteration in original) (emphasis added) (footnote 

omitted). The letter went on to recite that “EPA’s failure to exercise its statutory authority to 

sharply cut GHG emissions is consigning much of our nation and this planet to an inhospitable 

future. This inaction . . . constitutes an enormous violation of the public trust.” WELC Notice 

Letter at 3 (emphasis added). This language plainly identifies section 213 as the provision of the 

Act responsible for the duty it alleges and makes clear that plaintiffs will challenge EPA’s 

“failure to exercise its statutory authority to sharply cut GHG emissions” — not merely its failure 

to make some reply to plaintiffs’ petitions. Under EPA’s own regulations, no more is required. 

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Moreover, the Court agrees with plaintiffs that the purpose of the pre-suit notice 

requirement has been served here. Notice requirements like this one are intended to preserve an 

agency’s authority to enforce the regulations within its bailiwick (by preventing citizen suits from 

supplanting agency action) and to allow the agency “an opportunity to bring itself into complete 

compliance with the Act and thus . . . render unnecessary a citizen suit.” Hallstrom, 493 U.S. at 

29 (quoting Gwaltney of Smithfield, Inc. v. Chesapeake Bay Found., Inc., 484 U.S. 49, 60 

(1987)) (internal quotation marks omitted). Here, plaintiffs’ notice letters — and the petitions 

that preceded them — apprised EPA of its putative obligations under the Act and accorded it 

ample opportunity to take whatever steps it saw as appropriate. Simply put, EPA cannot claim to 

have been ambushed by plaintiffs’ claims in this action. 

Conservation Force v. Salazar, 715 F. Supp. 2d 99, on which EPA relies, is not to the 

contrary. Conservation Force dealt with a provision of the Endangered Species Act requiring the 

Secretary of the Interior to make a preliminary finding on petitions submitted thereunder within 

90 days, and then to make a more substantial finding within 12 months. See 715 F. Supp. 2d at 

101. The Conservation Force plaintiffs brought suit challenging the Secretary’s failure to make 

the 12-month finding, but their notice letter only mentioned the 90-day step. Id. at 103. Finding 

that the letter made no mention of any other error related to the plaintiffs’ petition, the 

Conservation Force court held that the plaintiffs’ 12-month-finding claim could not proceed. Id. 

at 104; see also Common Sense Salmon Recovery v. Evans, 329 F. Supp. 2d 96, 104 (D.D.C. 

2004) (holding that the plaintiffs’ notice was deficient because it “made no mention” of one of 

their claims). 

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There are two key differences between this case and Conservation Force. First, the 

Conservation Force plaintiffs’ notice letter “d[id] not mention” any procedural errors other than 

the failure to make a 90-day finding. Id. at 103. Here, as noted, pages of plaintiffs’ letters are 

devoted to EPA’s obligation to make endangerment findings pursuant to sections 213 and 231 — 

under which plaintiffs now bring their claims. Second, because the Conservation Force 

plaintiffs sent their notice letter before the Secretary’s obligation to make a 12-month finding had 

been triggered, it was impossible for either party to know at the time that such a finding would be 

required at all, let alone that the plaintiffs would file suit over its absence. Id. at 104. That is not 

the case here. 

In holding that plaintiffs’ notice was sufficient for their claims to proceed, the Court does 

not find fault with EPA’s argument that, as a condition on the government’s waiver of sovereign 

immunity, the Act’s notice requirement must be construed in the government’s favor. See Lane 

v. Peña, 518 U.S. 187, 192 (1996). But the proper construction of the Act is not at issue here. 

EPA’s own regulations require only “reasonable specificity.” 40 C.F.R. § 54.3(a). Plaintiffs 

could have stated their intentions with greater clarity, but their failure to do so does not deprive 

the Court of jurisdiction where their notice of intent to sue identified their present claims with the 

requisite specificity. 

B. EPA’s Duty to Make Endangerment Findings 

Having concluded that it has jurisdiction over plaintiffs’ determination claims, the Court 

turns to EPA’s argument that those counts fail to state a cognizable claim for unreasonable delay. 

Because “a delay cannot be unreasonable with respect to action that is not required,” Norton v. S. 

Utah Wilderness Alliance, 542 U.S. 55, 64 n.1 (2004), an unreasonable-delay claim requires that 

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the agency has a duty to act in the first place. Nat’l Ass’n of Home Builders v. U.S. Army Corps 

of Eng’rs, 417 F.3d 1272, 1280 (D.C. Cir. 2005); In re Am. Rivers & Idaho Rivers United, 372 

F.3d 413, 418 (D.C. Cir. 2004). Here, EPA contends that the Clean Air Act provisions on which 

plaintiffs rely — sections 213 and 231 — cannot support plaintiffs’ unreasonable-delay claims 

because they give EPA the discretion to conduct the endangerment findings that plaintiffs seek, 

but do not require it to do so. Because the two provisions use different language, the Court 

addresses them separately. 

1. Section 213 

Section 213, which is codified at 42 U.S.C. § 7547, deals with “emissions from nonroad 

engines and nonroad vehicles.” 42 U.S.C. § 7547(a). Paragraph 213(a)(4), at issue here, 

provides: 

If the Administrator determines that any emissions not referred to in [a prior 

paragraph] from new nonroad engines or vehicles significantly contribute to air 

pollution which may reasonably be anticipated to endanger public health or welfare, 

the Administrator may promulgate (and from time to time revise) such regulations 

as the Administrator deems appropriate . . . . 

42 U.S.C. § 7547(a)(4). EPA sees two loci of discretion in this language: the word “if” in the 

predicate clause, and the word “may” in the conditional clause. EPA argues that these terms vest 

it with discretion to determine (or not) whether any nonroad emissions “significantly contribute 

to air pollution which may reasonably be anticipated to endanger public health or welfare,” id., 

and, if so, to regulate (or not). Plaintiffs respond that the statutory language assumes that EPA 

will undertake the determination in question, with the word “if” denoting what will happen 

should that determination be affirmative, not should it occur and be affirmative. EPA has the 

stronger position. 

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Plaintiffs’ contention that paragraph 213(a)(4)’s language assumes that EPA will conduct 

endangerment findings is belied by the language of subsection 213(a)’s other provisions. Indeed, 

paragraph (4) stands out among the five paragraphs as the only one lacking a concrete deadline 

by which EPA must make an endangerment finding or take a related step. Paragraph (1) requires 

EPA to conduct a study by a certain date; paragraph (2) requires to EPA make an endangerment 

finding within twelve months of that study’s completion; paragraph (3) gives EPA another 

twelve months to promulgate regulations based on that finding; and paragraph (5) requires 

promulgation of other regulations by a specific date. See 42 U.S.C. § 7547(a)(1)–(3), (5). Unlike 

its counterparts, paragraph (4) is simply silent as to when — or whether — EPA must make 

endangerment findings; it merely says what EPA “may” do “if” an affirmative finding is made. 

The Court cannot assume that this difference is accidental. See Sosa v. Alvarez–Machain, 542 

U.S. 692, 711 n.9 (2004) (noting the “usual rule” that when one statute uses different terms, 

courts presume that different meanings are intended). 

Plaintiffs acknowledge that paragraph (4) lacks an express action requirement, but 

contend that without such a requirement, it would be incomplete or incoherent; they argue that 

allowing EPA to avoid regulating air pollution by refusing to conduct endangerment findings 

would defeat the purpose of the Act.2 The problem with this argument is that EPA’s 

interpretation of paragraph (4) — as a catch-all provision, designed to give EPA the flexibility to 

2 Plaintiffs also argue that the Supreme Court’s decision in Massachusetts v. EPA, 

549 U.S. 497, establishes EPA’s non-discretionary duty to undertake endangerment findings. 

But Massachusetts construed section 202 of the Act, see id. at 532–33, which uses language very 

different from that of section 213. Compare 42 U.S.C. § 7521(a)(1), with id. § 7547(a)(4). Thus, 

its interpretation of that provision is not useful in deciphering section 213. Moreover, 

Massachusetts, as explained further below, did not recognize a freestanding duty like that 

advocated by plaintiffs here. See infra subsection III.B.2. 

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deal with certain emissions if it decides that doing so is necessary — is neither incomplete nor 

incoherent. It is hardly implausible that Congress, having dealt specifically with “carbon 

monoxide, oxides of nitrogen, and volatile organic compounds” in paragraph (2), 42 U.S.C. 

§ 7547(a)(2), saw fit to give EPA discretion to deal as needed with other nonroad emissions. 

Further, because paragraph (4) provides that EPA “may” regulate in the event of an affirmative 

finding, an initial duty to conduct a finding would have little force; if EPA wished to avoid 

regulating, it would remain free to do so. And finally, EPA’s interpretation of paragraph (4) 

avoids a non-trivial difficulty raised by plaintiffs’: if plaintiffs are correct that paragraph (4) 

includes a non-discretionary obligation, at what time and under what circumstances is that 

obligation triggered? Plaintiffs offer no answer to this question, a fact that undercuts their 

argument that a non-discretionary obligation is present. See In re Bluewater Network, 234 F.3d 

1305, 1315 (D.C. Cir. 2000). 

In sum, the Court cannot conclude that paragraph 213(a)(4) was intended to require EPA 

to conduct endangerment findings. Its language lacks any such obligation, and inferring one 

would go beyond Congress’s express instructions and create practical difficulties. Plaintiffs may 

be right that, as a policy matter, EPA should always be obligated to conduct endangerment 

findings, but where Congress intends that outcome, it says so. See, e.g., 42 U.S.C. § 7547(a)(1)– 

(3). The Court cannot assume that Congress’s adoption of different language in paragraph (4) “is 

attributable to sloppy draftmanship.” Motor & Equip. Mfrs. Ass’n, Inc. v. EPA, 627 F.2d 1095, 

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1113 (D.C. Cir. 1979). Accordingly, counts two and three of plaintiffs’ complaint must be 

dismissed for failure to state a claim.3 

2. Section 231 

Section 231, which addresses aircraft emissions and is codified at 42 U.S.C. § 7571, 

provides in part that EPA “shall, from time to time, issue proposed emission standards applicable 

to the emission of any air pollutant from any class or classes of aircraft engines which in [its] 

judgment causes, or contributes to, air pollution which may reasonably be anticipated to endanger 

public health or welfare.” 42 U.S.C. § 7571(a)(2)(A). Plaintiffs contend that the Supreme 

Court’s decision in Massachusetts v. EPA, 549 U.S. 497, which construed almost identical 

language in section 202 of the Act, establishes that this provision imposes a non-discretionary 

obligation on EPA to make endangerment findings. EPA counters that the statutory language 

does not require EPA to act, and that Massachusetts did not resolve this question. 

First, EPA is correct that Massachusetts does not govern here. There, as here, the 

plaintiffs submitted a rulemaking petition to EPA (in that case, seeking regulation of greenhousegas emissions from motor vehicles). Id. at 510. But there, unlike here, EPA responded to — and 

denied — the petition. EPA stated that it lacked the authority to address climate change and that, 

3 Contrary to plaintiffs’ objections, the dismissal of these claims does not grant 

EPA unfettered discretion to avoid regulating nonroad and marine emissions. Plaintiffs’ nonroad 

and marine petitions remain pending before EPA, and plaintiffs’ claim that EPA has unduly 

delayed its response to those petitions will remain before this Court. If plaintiffs prevail on that 

claim, the Court will be empowered to order EPA to act on plaintiffs’ petitions. See 42 U.S.C. 

§ 7604(a) (“The district courts of the United States shall have jurisdiction to compel . . . agency 

action unreasonably delayed . . . .”). And if EPA denies those petitions in whole or in part, 

plaintiffs will have recourse in the U.S. Court of Appeals for the District of Columbia Circuit, 

see id. § 7607(b)(1), which will ensure that EPA’s stated reasons for denying the petitions are 

consistent with the Act’s language and structure. See Massachusetts, 549 U.S. at 533–34. 

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even if it had that authority, it would decline to do so for various policy reasons. Id. at 511. The 

Supreme Court found EPA’s denial of the petition to be arbitrary and capricious. First, the Court 

held that EPA did have the authority to issue the requested regulations. Id. at 528–32. Second, 

and more importantly for present purposes, the Court held that EPA erred by declining, for policy 

reasons, to regulate. Looking to section 202, which (like section 231) states that EPA “shall” 

regulate “emission[s] . . . which in [its] judgment cause, or contribute to, air pollution,” 42 

U.S.C. § 7521(a)(1), the Court concluded that EPA could only decline to regulate if it determined 

that the emissions in question did not cause or contribute to air pollution, or that such a 

determination could not be made. Massachusetts, 549 U.S. at 532–33. 

Plaintiffs rely on the Massachusetts Court’s interpretation of section 202 to argue that 

section 231’s near-identical language requires EPA to conduct endangerment findings. But, as 

EPA points out, Massachusetts’s holding does not reflect a conclusion that section 202 imposes 

an independent obligation on EPA to conduct endangerment findings. Rather, the Court held that 

“once EPA has responded to a petition for rulemaking, its reasons for action or inaction must 

conform to the authorizing statute.” Id. at 533 (emphasis added). Having concluded that EPA’s 

stated reasons did not so conform, the Court explained that it “need not . . . reach the question 

whether on remand EPA must make an endangerment finding . . . . We hold only that EPA must 

ground its reasons for action or inaction in the statute.” Id. at 534–35 (internal citation omitted) 

(citing Chevron U.S.A. Inc. v. Natural Res. Def. Council, Inc., 467 U.S. 837, 843–844 (1984)). 

This discussion makes clear that the Massachusetts Court was addressing EPA’s 

obligations when responding to a rulemaking petition; that is, the Court held that where a party 

has petitioned EPA to conduct a rulemaking under section 202, EPA may not decline to do so for 

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reasons beyond the scope of the Act. The Court did not hold that section 202 itself obligates 

EPA to conduct that rulemaking or make the predicate endangerment finding. Thus, 

Massachusetts does not establish a duty of the type that plaintiffs propose here. 

But that fact does not end the Court’s inquiry. The question remains whether section 231 

itself creates such a duty. EPA acknowledges that paragraph 231(a)(2)(A)’s use of mandatory 

language, see 42 U.S.C. § 7571(a)(2)(A) (“[EPA] shall . . . issue proposed emission standards 

. . . .” (emphasis added)), creates a post–endangerment finding duty to regulate, but argues that it 

does not require EPA to conduct the endangerment finding in the first place. Plaintiffs respond 

that such a construction would defeat the purpose of the Act by allowing EPA to shirk its duty to 

combat air pollution. The Court agrees with plaintiffs. 

EPA reads paragraph 231(a)(2)(A) in a vacuum, but it cannot be understood without 

reference to the provisions around it. Subsection 231(a) reads: 

(1) 	 Within 90 days after December 31, 1970, the Administrator shall commence 

a study and investigation of emissions of air pollutants from aircraft in order 

to determine— 

(A) the extent to which such emissions affect air quality in air quality 

control regions throughout the United States, and 

(B) the technological feasibility of controlling such emissions. 

(2) (A) The Administrator shall, from time to time, issue proposed emission 

standards applicable to the emission of any air pollutant from any 

class or classes of aircraft engines which in his judgment causes, or 

contributes to, air pollution which may reasonably be anticipated to 

endanger public health or welfare. 

(B) (i) The Administrator shall consult with the Administrator of the 

Federal Aviation Administration on aircraft engine emission 

standards. 

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(ii) 	 The Administrator shall not change the aircraft engine 

emission standards if such change would significantly 

increase noise and adversely affect safety. 

(3) 	 The Administrator shall hold public hearings with respect to such proposed 

standards. . . . Within 90 days after the issuance of such proposed regulations, 

he shall issue such regulations with such modifications as he deems 

appropriate. Such regulations may be revised from time to time. 

42 U.S.C. § 7571(a). These provisions, all of which use compulsory language, together create a 

comprehensive scheme for the regulation of harmful aircraft emissions, of which paragraph 

231(a)(2)(A) is the centerpiece: no other provision provides for the development of aircraft 

emissions standards. 

This statutory structure belies EPA’s assertion that paragraph 231(a)(2)(A) merely serves 

to provide EPA with discretion to conduct endangerment findings. Congress’s use of “shall” 

throughout subsection 231(a) suggests that it intended to mandate a certain outcome — the 

regulation of harmful aircraft emissions. See Allied Pilots Ass’n v. Pension Ben. Guar. Corp., 

334 F.3d 93, 99 (D.C. Cir. 2003) (noting that “shall” is ordinarily a command). That purpose 

would be defeated by allowing EPA to avoid triggering its obligation to regulate in the first 

place. Indeed, EPA offers no explanation why Congress might have mandated the second step in 

a two-step regulatory process while leaving the first step to the discretion of the agency; after all, 

if step one is discretionary, the “shall” that appears to require step two becomes largely nugatory. 

Such an outcome is inconsistent with Congress’s use of mandatory language and the stated 

function of the provisions in question.4 

4 The Court does not suggest that Congress could never have a reason to create a 

regulatory structure in which a discretionary first step triggers a mandatory second step; but 

where, as here, the first step is a factual determination that does not turn on policy questions — 

do aircraft emissions contribute to harmful air pollution? — the Court sees no basis to infer that 

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A comparison with paragraph 213(a)(4), discussed above, is instructive: there, the 

conclusion that EPA could decide whether to take step one was consistent with the fact that EPA 

had express discretion whether to take step two. See 42 U.S.C. § 7547(a)(4) (providing that if 

EPA makes an affirmative endangerment finding, it “may promulgate . . . such regulations as [it] 

deems appropriate” (emphasis added)). Indeed, the fact that paragraph 231(a)(2)(A) does not 

employ paragraph 213(a)(4)’s “if, then” structure further suggests that the two provisions are 

intended to operate differently. Compare 42 U.S.C. § 7547(a)(4), with id. § 7571(a)(2)(A); see 

Sosa, 542 U.S. at 711 n.9 (different statutory terms imply different meanings). And, whereas 

paragraph 213(a)(4) could plausibly be read as a catch-all provision because other paragraphs 

around it created a mandatory regime of regulation, paragraph 231(a)(2)(A) cannot: it is, as noted 

above, the only provision in section 231 that provides for the development of aircraft emissions 

standards. 

Moreover, the Act’s history suggests that paragraph 231(a)(2)(A) was and is intended to 

create a duty to conduct endangerment findings. When originally enacted in 1970, instead of 

“The Administrator shall, from time to time, issue proposed emission standards,” paragraph 

231(a)(2)(A) began with: “Within 180 days after commencing [the] study and investigation 

[required by paragraph (a)(1)], the Administrator shall publish a report of such study and 

investigation and shall issue proposed emission standards.” Clean Air Amendments of 1970, 91 

Congress intended to allow EPA to avoid the effect of mandatory statutory language merely by 

declining to make that determination in the first place. The fact that paragraph 231(a)(2)(A) 

refers to the endangerment finding as a “judgment” does not alter this conclusion. See 

Massachusetts, 549 U.S. at 532–33 (“While the statute does condition the exercise of EPA’s 

authority on its formation of a ‘judgment,’ that judgment must relate to whether an air pollutant 

‘cause[s], or contribute[s] to, air pollution which may reasonably be anticipated to endanger 

public health or welfare.’” (quoting 42 U.S.C. § 7521(a)(1)) (internal citations omitted)). 

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Case 1:10-cv-00985-HHK Document 25 Filed 07/05/11 Page 18 of 19 

Pub. L. No. 604, 84 Stat. 1676, 1704 (1970) (emphasis added). The fact that this language 

required EPA to take two discrete steps by a concrete deadline strongly suggests that the 

predicate determination was never intended to be a separate, discretionary phase, but rather was 

part and parcel of the study-and-regulate scheme that EPA was required to follow. That 

impression is reenforced by the House Report on the 1970 Act. See H.R. REP. No. 91-1146 

(1970), reprinted in 1970 U.S.C.C.A.N. 5356, 5369–70 (“Section 231 directs the Secretary to 

prescribe, as soon as practicable . . . emissions standards for any class of aircraft or aircraft 

engines which cause or contribute to [harmful] air pollution . . . .” (emphasis added)). There is 

no indication that the change to the current language, which occurred in 1977, see Clean Air Act 

Amendments of 1977, Pub. L. No. 95–95, 91 Stat. 685, 791 (1977), was intended to do anything 

more than provide EPA with some flexibility as to when it had to regulate.5 

Finally, the current version of paragraph 231(a)(2)(A) does not, unlike paragraph 

213(a)(4), lack any indication of when EPA’s obligation to conduct endangerment findings is 

triggered. It requires EPA to act “from time to time,” 42 U.S.C. § 7571(a)(2)(A), a phase that, 

while vague, allows for judicial review of an agency’s allegedly unreasonable delay. See Am. 

Lung Ass’n v. Reilly, 962 F.2d 258, 263 (2d Cir. 1992) (“[W]hen a statute requires agency action 

at indefinite intervals, such as ‘from time to time’ . . . ‘unreasonable delay’ [can] be a meaningful 

standard for judicial review.”). Thus, an unreasonable delay claim brought to enforce paragraph 

5 The House Report and House Conference Report to the 1977 amendments do not 

address the purpose or meaning of this change. See H.R. REP. No. 95-294 (1977), reprinted in 

1977 U.S.C.C.A.N. 1077; H.R. CONF. REP. No. 95-564 (1977), reprinted in 1977 U.S.C.C.A.N. 

1502. 

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Case 1:10-cv-00985-HHK Document 25 Filed 07/05/11 Page 19 of 19 

231(a)(2)(A) would not lack any standard against which to judge the reasonableness of the 

agency’s performance. 

In sum: EPA’s interpretation of paragraph 231(a)(2)(A) does not accord with section 

231’s structure and purpose. Congress’s use of mandatory language, and paragraph 

231(a)(2)(A)’s role in the aircraft-emissions-regulation regime created by section 231, strongly 

suggest that Congress intended the predicate endangerment finding to be a compulsory step. 

Such a conclusion does not rob EPA of regulatory discretion; on the contrary, the D.C. Circuit 

has recognized that section 231 “confer[s] broad discretion to the Administrator to weigh various 

factors in arriving at appropriate standards” for aircraft emissions. Nat’l Ass’n of Clean Air 

Agencies v. EPA, 489 F.3d 1221, 1230 (D.C. Cir. 2007). But that discretion does not extend to 

eschewing a required component of the regulatory process. Accordingly, EPA’s motion to 

dismiss must be denied as to claim four. 

IV. CONCLUSION 

For the foregoing reasons, EPA’s motion to dismiss must be granted in part and denied in 

part. 

Accordingly, it is this 5th day of July 2011 hereby 

ORDERED that defendant’s partial motion to dismiss [#9] is GRANTED as to claims 

two and three of plaintiffs’ complaint and DENIED as to claim four. 

Henry H. Kennedy, Jr. 

United States District Judge 

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