United States Court of Appeals

For the First Circuit

No. 20-2195

SIERRA CLUB; NATURAL RESOURCES COUNCIL OF MAINE; APPALACHIAN 

MOUNTAIN CLUB,

Plaintiffs, Appellants,

v.

UNITED STATES ARMY CORPS OF ENGINEERS; COLONEL JOHN A. ATILANO, 

II, Commander and District Engineer, in his official capacity; 

JAY L. CLEMENT, Senior Project Manager, in his official 

capacity; CENTRAL MAINE POWER COMPANY,

Defendants, Appellees.

APPEAL FROM THE UNITED STATES DISTRICT COURT

FOR THE DISTRICT OF MAINE

[Hon. Lance E. Walker, U.S. District Judge]

Before

Lynch, Thompson, and Barron,

Circuit Judges.

Kevin Cassidy, with whom Earthrise Law Center was on brief, 

for appellants. 

Jeffrey A. Hall, with whom Jean E. Williams, Acting Assistant 

Attorney General, Jennifer S. Neumann, and Amelia G. Yowell were 

on brief, for appellees United States Army Corps of Engineers, 

John A. Atilano II, and Jay L. Clement. 

Joshua D. Dunlap, with whom Matthew D. Manahan, Lisa 

Gilbreath, and Pierce Atwood LLP were on brief, for appellee

Central Maine Power Company.
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Kevin Poloncarz, Donald L. Ristow, Lindsay Brewer, and 

Covington & Burling LLP on brief for amici curiae Calpine 

Corporation, Nextera Energy Resources, LLC, and Vista Corp.

Shaun A. Goho and the Emmett Environmental Law & Policy Clinic

on brief for amici curiae Environmental Law Clinic Directors.

Anthony W. Buxton, Jonathan G. Mermin, and Preti Flaherty on 

brief for amicus curiae Industrial Energy Consumer Group.

P. Andrew Hamilton, Timothy C. Woodcock, and Eaton Peadbody, 

P.A. on brief for amicus curiae H.Q. Energy Services (U.S.) Inc.

May 13, 2021

 
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LYNCH, Circuit Judge. Plaintiff environmental 

organizations appeal from the district court's denial of 

preliminary injunctive relief barring construction of Segment 1 of 

a planned five-segment electric transmission power corridor in 

Maine. This was part of a larger project which would run from 

Quebec, Canada to Massachusetts. See Sierra Club v. U.S. Army

Corps of Eng'rs, No. 2:20-CV-00396-LEW, 2020 WL 7389744, at *1 (D. 

Me. Dec. 16, 2020) ("CMP Decision").

The corridor would be built by Central Maine Power 

("CMP"), a private company. Plaintiffs' challenge is to the Army 

Corps of Engineers' ("Corps") decision, after its performance of 

an Environmental Assessment ("EA"), to issue a permit authorizing

CMP to take three actions in Segment 1: (1) temporarily fill 

certain wetlands, (2) permanently fill other wetlands, and (3)

construct a tunnel under the Kennebec River. They allege that the 

Corps was required to issue not merely an EA, but a full 

Environmental Impact Statement ("EIS") and that the Corps acted 

arbitrarily or capriciously in conducting its EA and issuing a 

Finding of No Significant Impact ("FONSI"). They raise other 

secondary challenges to the Corps' EA and FONSI. We conclude that

that plaintiffs have failed to show a likelihood of success on the 

merits. We affirm the district court's denial of a preliminary 
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injunction.1 We also vacate the injunction issued by this court

on January 15, 2021 to allow us to consider this expedited appeal.

I. Background

A. State Agency Review of the CMP Corridor.

The parameters for the project were originally set by 

Massachusetts. Massachusetts selected the CMP proposal from 

fifty-three proposed clean energy projects in a competitive 

bidding process.2 State regulators and private utilities were 

responsible for that selection. No federal agency was involved. 

Massachusetts approved only the specific route outlined in CMP's 

proposal. "The [Massachusetts] process essentially predetermined

CMP's role as applicant and limited the alternatives analysis to 

only those which are available and capable of being done by CMP." 

1 To earn a preliminary injunction, parties must 

demonstrate four factors: (1) the likelihood of success on the 

merits; (2) the likelihood of irreparable harm absent an 

injunction; (3) a balancing of hardships; and (4) the public 

interest. Respect Maine PAC v. McKee, 622 F.3d 13, 15 (1st Cir. 

2010) (citing Nken v. Holder, 556 U.S. 418, 433 (2009)). Sierra 

Club urges us to place less emphasis on the first prong, even 

though our case law has emphasized that prong's primacy in the 

preliminary injunction assessment. See Ryan v. ICE, 974 F.3d 9, 

18 (1st Cir. 2020) ("The movant's likelihood of success on the 

merits weighs most heavily in the preliminary injunction 

calculus."). Regardless, Sierra Club would not prevail even if we 

adopted their view of the test. We therefore need not decide the 

issue. 

2 Massachusetts originally selected the Northern Pass 

Transmission project, which would have travelled through New 

Hampshire. New Hampshire regulators did not approve the Northern 

Pass project. After that rejection, Massachusetts selected the 

CMP proposal through Maine. 
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Maine also approved the project after much more 

extensive review than the Corps engaged in in its EA. After CMP 

won the contract to construct the corridor, the Maine Department 

of Environmental Protection ("MDEP") accepted written and oral 

testimony about the project, and after a hearing approved 

construction. MDEP concluded that the CMP Corridor in its entirety 

had minimal environmental impacts, provided that CMP took 

mitigation measures, which it has agreed to undertake. The 

approved route consists of five segments, four of which track 

existing transmission lines. MDEP reviewed all 8,600 acres of the 

project, and issued a 113-page order approving the plan subject to 

various additional conditions, which CMP adopted. The MDEP

assessed the project impact on: (1) wildlife, (2) forest and 

habitat fragmentation, (3) depletion of natural resources, (4) 

disruption during construction, (5) the visual aesthetics of the 

region, and (6) the feasibility of alternatives. It concluded 

that subject to mitigation measures to limit the visual and 

environmental impacts of the project, the CMP corridor did not 

impose unreasonable environmental risks. The Corps reviewed the 

project as modified by the State of Maine. 

The Maine Public Utilities Commission also approved the 

project after holding public hearings and accepting public 

comment. The Maine Law Court later upheld that approval. NextEra

Energy Res., LLC v. Me. Pub. Utils. Comm'n, 227 A.3d 1117, 1119
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(Me. 2020). The Maine Bureau of Parks and Lands also leased to 

CMP a right of way over state land. 

B. Federal Agency Review of the CMP Corridor.

The Corps became involved in the CMP project because 

construction in Segment 1 will require (1) temporary filling of 

wetlands; (2) permanent filling of wetlands; and (3) construction 

of a tunnel under the Kennebec River.3 Each of these activities 

requires permit approval from the Corps under either the Clean 

Water Act (for temporary and permanent fills) or the River and 

Harbors Act (for tunneling under the Kennebec River). 33 U.S.C. 

§§ 403, 1341, 1344(a).

Federal law requires the Corps to consider the 

environmental impact of permitting these activities. The National 

Environmental Protection Act ("NEPA") is a procedural statute. 42 

U.S.C. § 4332(C). It sets out environmental policy objectives 

which are largely implemented through regulations promulgated by 

the Council on Environmental Quality ("CEQ") and individual 

agencies. See Sierra Club v. U.S. Army Corps of Eng'rs, 803 F.3d 

31, 37 (D.C. Cir. 2015) ("Flanagan South"). 

Two categories of CEQ and Corps regulations are relevant 

to this litigation. The first concerns the appropriate scope of 

3 At MDEP's request, the Corps also advised MDEP that a 

"zig zag" route through CMP's 300-foot-wide right of way would not 

significantly mitigate impacts to wetlands, and could cause other 

environmental consequences. 
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the required review. It is uncontested that NEPA applies only to 

"major [f]ederal actions." 42 U.S.C. § 4332(C). Whether a project 

is a major federal action is itself governed by federal law. The 

scope of the required federal environmental review of the CMP 

corridor, as it involves a private project over state or private 

land, is in turn governed by regulations from two federal agencies, 

CEQ and the Corps. 

CEQ regulations state "[i]n assessing whether NEPA 

applies or is otherwise fulfilled, Federal agencies should 

determine . . . . [w]hether the proposed activity or decision is 

a major Federal action [or if other factors not relevant here 

excuse compliance with NEPA]." 40 C.F.R. § 1501.1 (emphasis 

added). 

The Corps has promulgated more detailed rules for 

determining the proper scope of its NEPA analysis. 33 C.F.R. pt. 

325, app. B, § 7(b) ("Appendix B") says: 

In some situations, a permit applicant may 

propose to conduct a specific activity 

requiring a Department of the Army (DA) permit 

(e.g., construction of a pier in a navigable 

water of the United States) which is merely 

one component of a larger project (e.g., 

construction of an oil refinery on an upland 

area). The district engineer should establish 

the scope of the NEPA document (e.g., the EA 

or EIS) to address the impacts of the specific 

activity requiring a DA permit and those 

portions of the entire project over which the 

district engineer has sufficient control and 

responsibility to warrant Federal review.
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Id. § 7(b)(1). The Corps further identifies four "[t]ypical 

factors to be considered in determining whether sufficient 

'control and responsibility' exists" over "portions of the entire 

project" requiring NEPA review beyond the "impacts of the specific 

activity requiring a [Corps] permit." These are: 

(i) Whether or not the regulated activity 

comprises "merely a link" in a corridor type 

project (e.g., a transportation or utility 

transmission project).

(ii) Whether there are aspects of the 

upland facility in the immediate vicinity of 

the regulated activity which affect the 

location and configuration of the regulated 

activity.

(iii) The extent to which the entire 

project will be within Corps jurisdiction.

(iv) The extent of cumulative Federal 

control and responsibility.

Id. § 7(b)(2). Appendix B further states:

[I]f an applicant seeks a [Corps] permit to 

fill waters or wetlands on which other 

construction or work is proposed, the control 

and responsibility of the Corps, as well as 

its overall Federal involvement would extend 

to the portions of the project to be located 

on the permitted fill. However, the NEPA 

review would be extended to the entire 

project, including portions outside waters of 

the United States, only if sufficient Federal 

control and responsibility over the entire 

project is determined to exist; that is, if 

the regulated activities, and those activities 

involving regulation, funding, etc. by other 

Federal agencies, comprise a substantial 

portion of the overall project.

Id. § 7(b)(3)(emphasis added). 
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A second category of regulations governs the nature of 

the environmental inquiry the Corps is required to do. CEQ 

regulations say that agencies should identify categories of agency 

actions that do not normally require preparation of an EA or EIS. 

For all other actions, CEQ states agencies should first prepare an 

EA to determine whether more detailed analysis is necessary. 40 

C.F.R. § 1501.4-5. The EA must "[b]riefly provide sufficient 

evidence and analysis for determining whether to prepare an [EIS] 

or a [FONSI]."4 40 C.F.R. § 1501.5. 

CEQ regulations set out ten factors for the agency to 

consider in assessing the impact from a proposed action and whether 

an EIS is necessary. 40 C.F.R. § 1508.27(b)(1)-(10). 

C. Environmental Findings of the Corps, Conclusions of Law, 

and the Scope of Review.

Applying these rules, the Corps limited the scope of its 

environmental review to the jurisdictional waters that required a 

permit from the Corps for construction. It weighed each of the

four Appendix B factors, and found no reason to expand the scope 

of its review beyond the environmental impact of its own permit. 

The Corps found that it had only limited jurisdiction over a small 

4 Other circuits have described an EA as "a rough-cut, 

low-budget environmental impact statement designed to show whether 

a full-fledged environmental impact statement -- which is very 

costly and time-consuming to prepare and has been the kiss of death 

to many a federal project -- is necessary." Spiller v. White, 352 

F.3d 235, 237-38 (5th Cir. 2003) (quoting Sabine River Auth. v. 

U.S. Dep't of Interior, 951 F.2d 669, 677 (5th Cir. 1992)).
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portion of the project, and accordingly this did not warrant review 

of the entire CMP Corridor. In particular, it repeatedly 

emphasized that activities requiring a Corps permit "compris[e] 

approximately 1.9% of the total project corridor." The Corps also 

found that the total cumulative federal oversight was insufficient 

to "federalize" the entire project. It stated, "[t]he scope of 

review . . . does not overlap with [other federal agencies'

review]."

The Corps conducted an EA for the activities that fell 

within its limited jurisdiction. The Corps incorporated MDEP's 

comprehensive environmental analysis into its own analysis. It

also incorporated the U.S. Fish and Wildlife Service's ("FWS") 

analysis of the impact of the project on endangered species. The 

U.S. Department of Energy ("USDOE") further acted as a consulting 

and cooperating agency during the Corps' EA process. 

The Corps made findings as to a number of potential 

environmental impacts. It concluded, for example, that "forest 

fragmentation as a result of activities within . . . [the Corps'] 

jurisdiction is not significant," and it assessed the potential 

loss of habitat for a number of Maine species, and in particular 

the impact under the Endangered Species Act. It also considered 

CMP's proposed mitigation measures. Its review took approximately 

three years. During that period, the Corps issued notice of its 

proposed action, and accepted hundreds of public comments. It 
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also conducted a public hearing and considered alternatives to the 

proposed CMP route. In its 164-page final EA, issued on July 7, 

2020, the Corps found no significant environmental impacts from 

the issuance of a permit for the three categories of activity 

requiring a Corps permit. 

We outline the Corps' description of the entire project 

and the role of Segment 1 within it. The entire five-segment CMP 

corridor consists of approximately 144.9 miles of transmission 

lines running from the Maine/Canadian border to a substation in 

Lewiston, Maine, where it connects to existing power 

infrastructure. The Corps' EA found the majority of the corridor 

route follows existing transmission lines. It concluded that

Segment 1 covers 53.1 miles, which passes through primarily

commercially harvested timber forest, crosses the Kennebec River, 

then continues through largely undeveloped stretches of the 

Western Maine Mountains. In Segment 1, only 0.26 acres of wetlands 

will be permanently filled. The Corps noted that along Segment 1, 

14.08 miles will remain entirely forested, and the remainder of 

the corridor will involve "tapered" clearing, which limits the 

impact on forest fragmentation.

The Corps stated that along the entire corridor, 4.87 

acres of wetlands will be permanently filled during the 

construction, and by power stations and poles. An additional 47.64 

acres will be temporarily filled during construction. 111.55 acres 
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of wetlands will be affected by forest cover clearing. The Corps 

identified 1404 distinct wetlands and 757 vernal pools located 

within the transmission line portions of the entire project. Of 

these, 82 wetlands and 83 vernal pools would be partially affected 

by permanent fills. 

The Corps also noted that CMP will undertake a number of 

mitigation measures to offset environmental impacts from the 

corridor. CMP committed to "conserv[ing] 40,000 acres of land in 

the vicinity of Segment 1" "to address the project's impact on 

habitat fragmentation and wildlife movement." Along the entire 

project CMP committed to preserving "in perpetuity" a further 

1022.4 acres of land, including 510.75 acres of wetlands.

The Corps also reviewed FWS's biological assessment and 

concluded that construction in the areas requiring a permit from 

the Corps had a limited impact on endangered species.

Accordingly, the Corps issued a FONSI, and did not 

prepare a more intensive EIS.

D. Other Federal Agency Review of the CMP Corridor 

project.

Three other federal agencies issued permits to CMP as 

well. The USDOE became involved solely as to the issuance of a 

Presidential Permit necessary to approve an international border 

crossing. On January 14, 2021, after plaintiffs brought this 

appeal, USDOE issued a Presidential Permit allowing the border 
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crossing. In that context, USDOE reviewed the environmental 

impacts of the project before issuing that permit, but all parties 

agree that it did not conduct an EIS, as plaintiffs seek here.5 

The FWS also licensed the taking of endangered species 

during construction. FWS reviewed the impact of the project on 

endangered species, as reflected in the Corps' own EA. Finally, 

the Federal Energy Regulatory Commission ("FERC") approved CMP's 

transmission service agreements related to the corridor. FERC's 

review was limited to the potential impact from the project on 

rates paid by utility customers. 

II. Procedural History

Plaintiffs brought this lawsuit on October 27, 2020.6 

They argued that the Corps' EA and FONSI were arbitrary or

capricious in violation of the Administrative Procedure Act. 5 

U.S.C. § 706(2)(A). In particular, plaintiffs argued that the 

Corps failed to properly apply its own Appendix B regulations. 

They argued (1) the scope of the Corps' EA was too narrow, (2) the 

Corps failed to account for baseline environmental conditions in 

5 In fact, USDOE stated that it takes the position that 

it is not subject to NEPA, and its environmental review was 

entirely discretionary. U.S. Dep't of Energy, New England Clean 

Energy Connect Environmental Assessment, DOE/EA-2155, at 3 (Jan.

14, 2021), available at https://www.energy.gov/sites/default

/files/2021/01/f82/ea-2155-necec-2021-01.pdf.

6 We acknowledge and thank all of the amici curiae for 

their helpful submissions in this matter. 
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its EA, (3) the Corps underestimated the intensity of environmental 

impacts from the project and should have conducted an EIS, and (4)

the Corps failed to provide adequate opportunity for notice and 

comment. See CMP Decision at *9-10, *17. Plaintiffs also made 

other arguments which they do not raise on appeal. Id.

On December 16, 2020, the district court denied 

plaintiffs' motion for preliminary injunctive relief. It held, 

"the Corps gave each of its regulatory factors (in particular the 

scoping factors of 33 C.F.R. Part 325, Appendix B, and intensity 

factors of 40 C.F.R. § 1508.27 (2018)) due consideration and 

reasonably exercised judgment on the appropriate application of 

the same." Id. at *14. The district court also rejected 

plaintiffs' other challenges to the EA. 

On December 28, 2020, plaintiffs brought this 

interlocutory appeal. On December 30, 2020, plaintiffs filed an 

Emergency Motion for Injunction Pending Appeal. This court, as 

said, granted plaintiffs motion on January 15, 2021.7 

7 The same day CMP filed a Motion to Reconsider on the 

grounds that the USDOE had issued an EA and FONSI that covered all 

of Segment 1, which CMP argued satisfied plaintiffs' request for 

relief. At oral argument plaintiffs countered that assertion as 

untrue and made clear that the USDOE had not issued an EIS and 

that its claims against the Corps were not affected by the USDOE 

action. We denied the CMP motion on January 22, 2021.
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III. Analysis 

We review the district court's denial of plaintiffs' 

motion for a preliminary injunction for abuse of discretion. Corp.

Techs., Inc. v. Harnett, 731 F.3d 6, 10 (1st Cir. 2013). "[T]he 

trial court, at the preliminary injunction stage, need not predict 

the eventual outcome on the merits with absolute assurance, [and] 

an appellate court need not conclusively determine the merits of 

the underlying claims to execute abuse-of-discretion review." 

Ross-Simons of Warwick, Inc. v. Baccarat, Inc., 102 F.3d 12, 16 

(1st Cir. 1996) (citation omitted). The grant of a preliminary 

injunction is "an extraordinary remedy that may only be awarded 

upon a clear showing that the plaintiff is entitled to such 

relief." Winter v. Nat. Res. Def. Council, Inc., 555 U.S. 7, 22 

(2008). An agency decision is unlawful if it is "arbitrary, 

capricious, an abuse of discretion, or otherwise not in accordance 

with law." 5 U.S.C. § 706(2)(A). The reviewing court determines 

whether the agency action is arbitrary or capricious. Id. Here, 

plaintiffs have failed to demonstrate a likelihood that the Corps

acted arbitrarily and capriciously. 

To be clear about what is not at issue, plaintiffs make 

no argument that the Corps' general standards (codified in Appendix 

B) for whether an otherwise private project has been federalized 
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are inadequate.8 To the contrary, in their opening brief 

plaintiffs cite only to Appendix B as the applicable legal standard 

by which to adjudicate whether the Corps engaged in the proper 

scope of review. Accordingly, they have waived any challenge that

the Corps' Appendix B regulations are inconsistent with NEPA or 

fail to capture all relevant considerations.9 See White v. Hewlett

Packard Enter. Co., 985 F.3d 61, 70 (1st Cir. 2021) (citing 

Rife v. One W. Bank, F.S.B., 873 F.3d 17, 19 (1st Cir. 2017)) (an

issue not briefed on appeal is waived). Plaintiffs' lead argument 

is instead that they have shown a likelihood of success that the

Corps' application of the Appendix B factors was arbitrary or

capricious. Plaintiffs have not met their burden. The Corps 

applied each of the Appendix B factors with a reasoned discussion 

before reaching its conclusion. 

A central consideration, based on the record, 

articulated by the Corps as to each of the factors and as to its 

conclusion, was that its permitting jurisdiction over waters of 

the United States constituted only a small part of Segment 1 and 

8 Relatedly, defendants make no argument that Appendix B 

is too broad in federalizing a project and thus do not contend 

that the project would not be federalized if it met the conditions 

in Appendix B. 

9 As to the genesis of Appendix B, see generally William

B. Ellis & Turner T. Smith, Jr., The Limits of Federal 

Environmental Responsibility and Control Under the National 

Environmental Policy Act, 18 Env't L. Rep. 10055 (1988). 
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an even smaller part of the overall project. The Corps found that 

less than 2% of the overall corridor required a Corps permit. We 

do not repeat the other findings we described earlier in this 

opinion. The Corps also properly considered the cumulative effect 

of the activities of other federal agencies: FERC had in 2018 

allowed CMP to enter into service contracts; USDOE issued a 

Presidential Permit for the Canadian border crossing; FWS's 

analysis was incorporated into the Corps' EA; and FERC's analysis 

related solely to consumer rates. Plaintiffs have not shown a 

likelihood of success that the Corps' conclusion that the overall 

project was not a major federal action was arbitrary or capricious.

"The [Corps] is considered to have control and 

responsibility for portions of the project beyond the limits of 

Corps jurisdiction where the Federal involvement is sufficient to 

turn an essentially private action into a federal action." 

Appendix B § 7(b)(2). As we explained above, the Corps lists four 

factors that should typically be considered in determining whether 

sufficient federal control exists. Id. Plaintiffs focus in large 

part on the first listed factor in Appendix B, "[w]hether or not 

the regulated activity comprises 'merely a link' in a corridor 

type project." Plaintiffs are correct that the examples in 

Appendix B do not address dispersed regulated activities or the 

import of multiple "links." But plaintiffs disregard the framing 

of the Appendix B factors as "[t]ypical factors to be considered." 
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Nothing in Appendix B suggests that if a regulated activity is not 

"merely a link" it necessarily indicates "sufficient control and 

responsibility" on the part of the Corps.10 Even assuming that, 

as plaintiffs argue, the Corps' regulated activity did not 

constitute "merely a link" and that, as the plaintiffs also argue, 

"there are aspects of the upland facility in the immediate vicinity 

of the regulated activity which affect [its] location and 

configuration,"11 we find that the Corps could reasonably rely on 

the negligible percentage of the entire project that is within 

Corps jurisdiction to conclude that the Corps did not have 

"sufficient control and responsibility to warrant Federal review" 

of the entire project.

Plaintiffs do challenge the Corps' conclusion that only

1.9% of the project is within the Corps' jurisdiction, suggesting 

10 In fact, it is possible to understand this first factor 

in Appendix B only as rejecting a particular form of but-for 

causation in the corridor-project context. See Ellis & Smith, 

supra note 7, at 10060-61; cf. Ohio Valley Env't Coal. v. Aracoma 

Coal Co., 556 F.3d 177, 195 (4th Cir. 2009) ("[T]he fact that the 

Corps' § 404 permit is central to the success of the valley-filling 

process does not in itself give the Corps 'control and 

responsibility' over the entire fill."). And, because this is a 

corridor-type project, we find the plaintiffs' reliance on White 

Tanks Concerned Citizens, Inc. v. Strock, 563 F.3d 1033, 1041 (9th 

Cir. 2009), unavailing. 

11 The Corps argues that this second factor "is inapt for 

corridor projects." "We defer to the Corps' interpretation unless 

it is plainly erroneous or inconsistent with Appendix B," Sierra 

Club, Inc. v. Bostick, 787 F.3d 1043, 1054 (10th Cir. 2015), but 

we need not resolve this interpretive question because we find 

that the factor is not dispositive even if it applies. 
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that the proper figure is 17%. Plaintiffs have failed to show, 

however, that the 1.9% figure excludes areas within the Corps'

jurisdiction. Cf. Flanagan South, 803 F.3d at 34 (analyzing a 

pipeline project and explaining that the agencies' actions, 

including the "Corps' Clean Water Act verifications of the 

pipeline's many water crossings," were "limited to discrete 

geographic segments of the pipeline comprising less than five 

percent of its overall length"). Moreover, as the Corps argued to 

us, both the 1.9% figure and the 17% figure are well under the 60% 

figure referenced in Appendix B's examples. See Appendix B 

§ 7(b)(3) ("[I]f 30 miles of [a] 50-mile transmission line crossed 

wetlands or other 'waters of the United States,' the scope of 

analysis should reflect impacts of the whole 50-mile transmission 

line."). 

Nor do plaintiffs' arguments about cumulative federal 

involvement suffice to tip the scale. For the reasons we have 

adverted to, the Corps could rationally conclude that the 

involvement of other agencies here did not rise to the level of 

cumulative involvement sufficient to trigger Appendix B's 

federalization theory. The Corps' holistic determination that 

"sufficient 'control and responsibility'" did not exist was not 

arbitrary or capricious.

Plaintiffs' remaining challenges also do not demonstrate 

a likelihood of success on the merits. Plaintiffs argue that (1)
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the Corps failed to adequately assess the baseline environmental 

conditions in Segment 1 in its EA, (2) apart from any argument 

about cumulative federal control, the Corps improperly "segmented" 

its own EA from the USDOE's analysis, (3) the Corps should have 

conducted an EIS, and (4) the Corps failed to provide adequate 

opportunity for notice and comment. In several of these claims 

plaintiffs rely on the premise we have rejected, that the Corps 

was obligated to review the entirety of Segment 1. In any event,

none have merit. 

The Corps assessed the baseline environmental conditions 

in its EA both in a standalone section, and in discussing the 

environmental impacts of the project. The Corps also incorporated 

the whole of MDEP's environmental analysis, which discussed 

baseline environmental conditions along the entirety of the CMP 

Corridor. Plaintiffs argue in conclusory terms that this 

assessment was insufficient. Plaintiffs have failed to show a 

likelihood of success on their claim that the Corps' assessment of 

the baseline environmental conditions was arbitrary and 

capricious.12

Plaintiffs next claim that the Corps improperly 

"segmented" its environmental analysis from USDOE's separate 

12 Half Moon Bay Fishermans' Mktg. Ass'n v. Carlucci, 857 

F.2d 505, 510 (9th Cir. 1988), on which plaintiffs rely, is plainly 

distinguishable. In Half Moon Bay the Corps "fail[ed] to set forth 

any baseline conditions." Id. (emphasis added). 
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assessment. This argument is waived. Plaintiffs did not raise it 

before the district court, and do not explain why they were unable 

to do so. See United States v. Zannino, 895 F.2d 1, 9 n.7 (1st 

Cir. 1990). While USDOE did not issue its final EA until January 

14, 2021, after plaintiffs filed this appeal, plaintiffs were aware 

that USDOE and the Corps were conducting separate EAs throughout 

the district court litigation. In any event, CEQ regulations 

direct agencies to coordinate in preparing an "impact statement." 

40 C.F.R. § 1508.25(a)(1). CEQ does not impose similar 

requirements on EAs and plaintiffs provide no other source of 

authority for such a requirement.

Plaintiffs also claim that the Corps should have 

conducted an EIS because "[t]he [corridor] will have significant 

impacts not only to aquatic resources but also the surrounding 

forest and wildlife." Again, plaintiffs fail to demonstrate that 

the Corps' decision to issue a FONSI instead of proceeding to an 

EIS was arbitrary or capricious. The Corps issued a 164-page EA, 

which analyzed the impacts of the Corps permits on wetlands, as 

well as surrounding forest land and wildlife. The Corps'

conclusions matched MDEP's own detailed environmental analysis. 

The Corps considered factors relating to the "intensity" of 

environmental impact pursuant to CEQ regulations. 40 C.F.R. 

§ 1508.27(b). Plaintiffs do not challenge those regulations. 

Instead, plaintiffs state "Segment 1 . . . will run through more 
- 22 -

than 800 aquatic resources, and will establish new, fragmenting 

electrical infrastructure through the Western Maine Mountains." 

Plaintiffs argue the Corps "failed to consider the effects from 

forest fragmentation." This is contrary to the record. The 

argument also fails because it depends on their already rejected 

assertion that Segment 1 is a major federal action.

Separately, plaintiffs claim that the project is 

scientifically "controversial" and therefore required an EIS. Cf.

Hillsdale Env'tl Loss Prevention, Inc. v. U.S. Army Corps of

Eng'rs, 702 F.3d 1156, 1181 (10th Cir. 2012). "Controversy is

only one of ten factors the Corps must consider when deciding

whether to prepare an EIS." Id. (citing 40 C.F.R. § 1508.27(b)(4)) 

"[It] is not decisive but is merely to be weighed in deciding what

documents to prepare." Town of Marshfield v. FAA, 552 F.3d 1,5

(1st Cir. 2008). Plaintiffs argue that they have submitted a

series of affidavits from experts who disagree with portions of

the Corps' EA analysis. Many of these claims rely on plaintiffs'

unsuccessful argument that the Corps was obligated to consider the

environmental effects along the entirety of Segment 1. Plaintiffs

and their experts argue, for example, that the greenhouse gas

reductions from the CMP Corridor are overstated, and that the

impacts of forest fragmentation are understated. Because we have

rejected plaintiffs' arguments as to scope, these arguments do not

show controversy. Plaintiffs' remaining claims also fail to show
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a scientific controversy requiring an EIS. The Corps considered

and responded to criticisms of its methodology and conclusions in

its EA, and its analysis accords with the detailed position of

MDEP. This situation is plainly distinguishable from the cases

that plaintiffs rely on. See Sierra Club v. U.S. Forest Serv.,

843 F.2d 1190, 1193-94 (9th Cir. 1988) (Forest Service approval of

timber sales for "experimental, untested and certainly unproven"

clearcutting of giant sequoias was controversial in light of

testimony and affidavits from biologists and conservationists

opposing the Forest Service's conclusions in its EA); Standing

Rock Sioux Tribe v. U.S. Army Corps of Eng'rs, 985 F.3d 1032, 1044-

46 (D.C. Cir. 2021) (agency decision was controversial where the

agency failed entirely to address in its EA criticisms about the

use of a particular leak detection technology that was untested

for pipelines like the one at issue). 

Finally, plaintiffs say that the Corps failed to provide 

adequate opportunities for notice and comment before issuing the 

final FONSI. But the "Corps did provide public notice and held a 

public hearing as part of its EA review process. The Corps' public 

hearing complemented other public hearings associated with the 

[CMP Corridor] but overseen by other agencies." CMP Decision at 

*11. As the district court noted, the Corps has discretion under 

CEQ rules as to whether it opens the final FONSI to 30 days of 

public comment. CEQ regulations require agencies to provide for 
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public involvement "to the extent practicable," 40 C.F.R. 

§ 1501.5(e), and hold or sponsor NEPA hearings "whenever 

appropriate or in accordance with the statutory requirements 

applicable to the agency," id. § 1506.6(c); see also CMP Decision

at *10. A 30-day comment period is only required if an EIS would 

ordinarily be required, or if the agency's proposed action is 

"without precedent." 40 C.F.R. § 1501.6(a)(ii). Neither condition 

is present here. 

IV.

The order of the district court is affirmed. This 

court's January 15, 2021 injunction is vacated.