United States Court of Appeals
                       For the First Circuit


No. 10-1972

              SAFEGUARDING THE HISTORIC HANSCOM AREA'S
               IRREPLACEABLE RESOURCES, INC., ET AL.,

                            Petitioners,

                                 v.

                  FEDERAL AVIATION ADMINISTRATION,

                            Respondent,
                             _________

                   MASSACHUSETTS PORT AUTHORITY,

                            Intervenor.
                             _________

               PETITION FOR REVIEW OF AN ORDER OF THE

                  FEDERAL AVIATION ADMINISTRATION


                               Before

           Torruella, Selya and Lipez, Circuit Judges.


     Matthew F. Pawa, with whom Law Offices of Matthew F. Pawa,
P.C., Jonathan S. Klavens, and Klavens Law Group, P.C. were on
brief, for petitioners.
     Elizabeth S. Merritt, Stephen F. Hinchman, and Law Offices of
Stephen F. Hinchman, LLC on consolidated brief for National Trust
for Historic Preservation; Representatives Markey, Tierney, and
Tsongas; Boards of Selectmen of Towns of Bedford, Concord,
Lexington, and Lincoln; Hanscom Area Towns Committee; National
Parks Conservation Association; and Friends of Minute Man National
Park, amici curiae.
     Brian C. Toth, Attorney, Appellate Section, Environment &
Natural Resources Division, U.S. Department of Justice, with whom
Ignacia S. Moreno, Assistant Attorney General, John R. Donnelly,
and Lisa A. Holden were on brief, for respondent.
     Martin R. Healy, with whom Michael K. Murray, Goodwin Procter
LLP, David S. Mackey, Chief Legal Counsel, and Ira M. Wallach,
Associate Chief Legal Counsel, were on brief, for intervenor.




                          July 12, 2011
             SELYA, Circuit Judge.           The area around the venerable

towns   of   Lexington   and    Concord      is     commonly    regarded    as    the

birthplace of the American Revolution.                The communities in that

area, now fashionable Boston suburbs, are deservedly proud of both

their storied history and their aesthetic advantages.                       When an

affiliated arm of the state government — the Massachusetts Port

Authority (Massport) — sought to modernize a mixed-use airport in

the   vicinity,   a   phalanx     of   preservationist         organizations       and

concerned citizens treated the move as a call to arms.                     Massport

nevertheless pushed ahead with its desired project and asked the

Federal Aviation Administration (FAA) to authorize the demolition

of an existing hangar and allow the development of a state-of-the-

art fixed base operator (FBO) facility.                The upshot was an epic

battle fought with statutes, regulations, legal precedents, and

expert reports.

             The results of this battle are now before us by way of a

petition for judicial review of the FAA's order permitting the

project to proceed. The protagonists are ably represented, and the

petitioners have raised a gallimaufry of issues involving the

Department of Transportation Act, 49 U.S.C. § 303(c), the National

Historic     Preservation   Act    (NHPA),     16    U.S.C.    §   470f,    and   the

National Environmental Policy Act (NEPA), 42 U.S.C. §§ 4321-4347.

After   careful   consideration        of   the     parties'    briefs     and    oral

arguments, helpful submissions by amici, and an amplitudinous


                                       -3-
administrative record, we conclude that the painstaking process

conducted by the FAA comported with its responsibilities under the

dizzying      array   of    applicable       statutes   and    regulations.

Accordingly, we deny the petition.

I.   BACKGROUND

              Laurence G. Hanscom Field (Hanscom) is a general aviation

airport located in Bedford, Massachusetts.          The area teems with a

rich cornucopia of historically significant sites, including Minute

Man National Historical Park and Walden Pond (a designated national

historic landmark).

              During the middle of the twentieth century, the Army Air

Corps leased and operated Hanscom.           Later, the facility morphed

into a joint military and civilian operation.           Among other things,

Hanscom now serves as a relief valve for Logan International

Airport (the major airport in the Boston area), allowing Logan to

concentrate on large-scale commercial flights.

              Massport is an independent state authority established

under Massachusetts law, see 1956 Mass. Acts ch. 465, §§ 1-35,

which   has    operated    Hanscom's    civilian   component   since   1974.

Massport has intervened in these proceedings and staunchly defends

the FAA's decision to allow the requested demolition and subsequent

new construction.

              The focal point of the parties' dispute is Hangar 24,

which was originally built in Georgia, shipped to Massachusetts,


                                       -4-
and   reconstructed     at   Hanscom    in    1948.      For    several   decades,

Massachusetts Institute of Technology (MIT) leased the structure

and used it as a research facility.                   In 2001, MIT deemed it

unsuitable for that purpose.            The hangar has been vacant ever

since.

            Responding to a perceived demand for increased corporate

aircraft    services    at   Hanscom,    Massport      issued     a   request   for

proposals to redevelop the Hangar 24 site.               In 2005, it blessed a

proposal that contemplated replacing Hangar 24 with an FBO facility

that would "provide service, maintenance, fueling, and shelter for

general aviation aircraft."         Although the putative developer later

withdrew,    Massport    clung   to     the    concept    and    proceeded      with

preparations for the redevelopment of the Hangar 24 site as an FBO

facility — a facility compatible with the needs of modern-day

corporate aircraft.

            Massport's proposed course of action not only required it

to jump through a long line of statutory and regulatory hoops but

also drew considerable opposition from concerned citizens and

groups.    The ensuing battle was waged on a variety of fronts.                  In

July of 2006, a nonprofit organization, Save Our Heritage, Inc. (a

petitioner   here),     requested     that    the   Massachusetts      Historical

Commission (the Commission), see Mass. Gen. Laws ch. 9, §§ 26-27,

evaluate Hangar 24 for possible inclusion on the National Register

of Historic Places (the National Register).                    After mulling the


                                       -5-
matter, the Commission determined that Hangar 24 was eligible for

listing    only   under      Criterion      A    (association         with   significant

historical events) and Criterion B (association with the lives of

historically significant persons).                   See 36 C.F.R. § 60.4(a), (b).

In light of this determination, the Commission asked Massport to

study the hangar's condition and to consider alternative uses,

including     possible        rehabilitation               for   occupancy        by   the

Massachusetts Air and Space Museum.                  This suggestion proved to be

a dead end; after conducting a site inspection, the museum reported

that Hangar 24 fell "far short of what would be necessary to make

the museum a viable entity."

            Around     the    same    time,          Massport     hired      an   aviation

consultant, HNTB Corporation, to prepare a condition assessment and

feasibility study for Hangar 24. HNTB documented and described the

hangar's    condition,       and   found        it   "functionally        obsolete"     and

unsuitable    for      aviation      use.            Its     report    listed      several

alternatives for redeveloping the site.

            Federal law requires that, in order to remain eligible

for   funding,    an   airport     must     maintain         a   current     layout    plan

approved by the FAA.         49 U.S.C. § 47107(a)(16)(B).                  In evaluating

a layout plan, "[t]he FAA's primary mission is to ensure the

safety, security, and efficiency of the National Airspace System."

Exec. Order No. 13,180, 65 Fed. Reg. 77,493, 77,493 (Dec. 11,

2000), as amended by Exec. Order No. 13,264, 67 Fed. Reg. 39,243


                                          -6-
(June 7, 2002); see also 49 U.S.C. § 47101(a).              No facility that

adversely affects the safety, utility, or efficiency of the airport

can be included in such a plan.         49 U.S.C. § 47107(a)(16)(C).

            The FAA became involved with the Hangar 24 project to

fulfill these responsibilities.              It engaged in a consultation

process and prepared an environmental assessment (EA) effective as

of June 18, 2010.      The EA addressed the potential environmental

impacts of Massport's redevelopment proposal, as well as its

effects on historic properties.

            In due course, the FAA approved the demolition and

replacement    of   Hangar   24   as    the     only   feasible   and   prudent

alternative, found that replacing it would have no adverse effect

within the meaning of the NHPA (save for the effect on Hangar 24

itself), and found no significant impact under the NEPA.                   The

petitioners filed a timely petition for judicial review, see 49

U.S.C. § 46110, in which they challenge the FAA's actions as

noncompliant with the Transportation Act, the NHPA, and the NEPA.

It is to these challenges that we now turn.

II.   ANALYSIS

            Our standard of review is familiar.           We must uphold the

FAA's findings of fact as long as they are supported by substantial

evidence.     See 

           "Substantial evidence is 'such

relevant evidence as a reasonable mind might accept as adequate to

support a conclusion.'"       Penobscot Air Servs., Ltd. v. FAA, 164


                                       -7-
F.3d 713, 718 (1st Cir. 1999) (quoting Universal Camera Corp. v.

NLRB, 

, 477 (1951)); see Allentown Mack Sales & Serv.,

Inc.   v.    NLRB,   

,    377   (1998)    (explaining    that

"substantial evidence" standard "gives the agency the benefit of

the doubt").

             We review an agency's compliance with section 4(f) of the

Transportation Act in accordance with the Administrative Procedure

Act (APA), 5 U.S.C. §§ 551-559, 701-706.            See Citizens to Pres.

Overton Park, Inc. v. Volpe, 

, 416 (1971).              Under the

APA,   we   may   set   aside   agency    action   if    it   is   "arbitrary,

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

with law."    5 U.S.C. § 706(2)(A).      The same metric governs judicial

review of agency action under both the NHPA, see Neigh. Ass'n of

the Back Bay, Inc. v. Fed. Transit Admin., 

, 58 (1st

Cir. 2006), and the NEPA, Dep't of Transp. v. Pub. Citizen, 

, 763 (2004).      Agency action fails under this standard "if

the agency relied on improper factors, failed to consider pertinent

aspects of the problem, offered a rationale contradicting the

evidence before it, or reached a conclusion so implausible that it

cannot be attributed to a difference of opinion or the application

of agency expertise." Assoc'd Fisheries of Me., Inc. v. Daley, 

, 109 (1st Cir. 1997).




                                    -8-
                           A.   Transportation Act.

            As    a     functional     matter,     section      4(f)     of    the

Transportation Act, which refers explicitly to the Secretary of

Transportation,         authorizes     federal    agencies      dealing       with

transportation matters to approve projects that entail the use of

historically significant sites.              49 U.S.C. § 303(c).         But this

authority    is   not    unbridled.      Approval    may   be   granted       in   a

particular case only if two preconditions are met: "(1) there is no

prudent and feasible alternative to using that land; and (2) the

program or project includes all possible planning to minimize

harm."      

apply both when a proposal

involves the physical use or occupation of a protected property

thought to be historic and when a proposal involves indirect (but

meaningful) effects on historic venues. Save Our Heritage, Inc. v.

FAA, 

, 58 (1st Cir. 2001).

            The EA prepared in connection with Massport's proposal to

demolish Hangar 24 explicitly considered four alternative courses

of action: 1) "[d]o nothing"; 2) "[l]ocate a new hangar facility

elsewhere on the airport"; 3) "[a]daptive reuse of Hangar 24"; and

4) "[r]eplace Hangar 24 as proposed by Massport." The EA concluded

that all of these alternatives were feasible, but that only the

fourth   was      prudent.       The    petitioners    dispute         the    FAA's

determination of what alternatives are or are not prudent.                    As a

fallback, they question whether the FAA has engaged in sufficiently


                                       -9-
thorough planning to minimize harm to historic sites.          We appraise

these challenges sequentially.

           1. Prudence. The doctrinal linchpin of the petitioners'

section 4(f) argument is their reading of the Supreme Court's

decision in Overton Park.      In their view, Overton Park holds that,

for the purpose of section 4(f), an alternative cannot be ruled out

as imprudent absent a strong showing of aposematic conditions,

manifested by "truly unusual factors," "extraordinary" costs and

community disruption, or "unique 

.      The

FAA's section 4(f) analysis, the petitioners say, does not measure

up to this benchmark.

           Like alchemists who would turn dross into gold, the

petitioners cherry-pick isolated phrases from the Overton Park

opinion   and   attempt   to   convert    those   phrases   into   a   broad,

inflexible holding.       This wordplay will not wash.         The Court's

mention   of    "truly    unusual,"      "extraordinary,"    and    "unique"

circumstances was intended as a gloss on the application of section

4(f) in a particular type of situation.           Those descriptive terms

were never meant to displace the statutory directive that the

agency determine whether an alternative is "prudent."              See Eagle

Found., Inc. v. Dole, 

, 804-05 (7th Cir. 1987); see

also Hickory Neigh. Def. League v. Skinner, 

, 163 (4th

Cir. 1990) (explaining that a section 4(f) evaluation need not




                                   -10-
explicitly find "unique problems" when record confirms "compelling

reasons for rejecting the proposed alternatives as not prudent").

          Context drives this point home.      Overton Park involved a

proposal to use publicly owned parklands for highway 

.    The Court reasoned that the cost of using public

land will almost always be less than that of acquiring private

property for alternate routes and that, in addition, building on

public parkland will almost always prove less disruptive to the

acquiring community because homes and businesses will not be

displaced.    

    These   verities   "are    common    to

substantially all highway construction."         

(emphasis

supplied).   If Congress had intended cost and community disruption

"to be on an equal footing with preservation of parkland," the

Court declared, section 4(f) would have been unnecessary.           

given by the Justices in Overton Park is

situation-specific, and comparing this case to Overton Park is like

comparing a plum to a pomegranate.        The Overton Park language is

tailored to fit situations in which, from a practical standpoint,

there otherwise would be a perverse incentive in favor of using

protected land for federal transportation projects.            Cf. City of

Dania Beach v. FAA, 

, 587 (D.C. Cir. 2010) (noting that

Overton Park analysis was premised on public/private cost and

disruption disparities and that it is this "automatic advantage"

that calls for "exceptional agency push-back").


                                   -11-
          Here, however, no such perverse incentive exists. All of

the feasible alternatives involve land that is already part of

Hanscom (i.e., land that is already government-owned). There is no

built-in impediment to preservation.      It would, therefore, make no

sense to wrest the quoted Overton Park language from its contextual

moorings and superimpose it upon the statutory imperative.       It is

the statute that ultimately controls our inquiry.            See Eagle

(examining Overton Park against backdrop

of section 4(f)'s language and concluding that an agency's "reasons

for using the protected land have to be good ones, pressing ones,

well thought out").1

          Let us be perfectly clear.        Without question, section

4(f) imposes significant obligations upon a reviewing agency.      See

Save Our 

.      But the petitioners' attempt to

festoon those obligations with magic words, selectively culled from

the Overton Park opinion, distorts the statute and overreads the

Court's teachings.     As a general matter, the agency's obligations

are what the statute says they are.      Thus, our focus must be on the

statute and its application to the facts at hand.     See 

.


     1
      At the expense of adding hues to a rainbow, we note that, in
compiling the EA, the FAA specifically stated that its prudence
inquiry centered on "extraordinary safety or operational problems"
(emphasis supplied). It seems to us that this reference indicates
that the agency proceeded in the spirit of Overton Park, albeit
adapting its inquiry to the vastly different circumstances before
it.

                                 -12-
           This brings us to the substance of the petitioners'

section   4(f)    challenge.          The   starting    point    is   the   FAA's

determination that none of the three explored alternatives to the

Massport proposal would be prudent.           In the pages that follow, we

examine the three rejected alternatives one by one.2

                               a.     Do Nothing.

           The petitioners complain about the FAA's analysis of the

"do nothing" alternative.           The agency rejected this alternative

because   "it    would   not   meet    Massport's      purpose   to   provide   an

additional location on the airport to service, maintain, fuel, and

shelter general aviation aircraft."

           "It is well settled that an alternative is not prudent if

it does not meet the transportation needs of a project."               Back 

.          The petitioners try to circumnavigate this

principle on the ground that Massport never established any "need"

for the Hangar 24 project.          This evasion is easily thwarted.




     2
       The petitioners protest that the FAA incorrectly disregarded
a fourth alternative: the possibility of locating the new FBO
facility at Worcester. But this suggestion surfaced for the first
time during the comment period, and the FAA persuasively responded
that, due to the approximately 50-mile distance between Hanscom and
Worcester, the idea was "not practical." This makes eminently good
sense for two reasons. First, the articulated need for a third FBO
facility was based on data evidencing increased corporate jet use
at Hanscom specifically, not in the region generally. Second, the
record indicates that improvements to infrastructure are not
usually in themselves sufficient to attract new activity to a
particular airport.    Air travel is, after all, tied clearly to
location.

                                       -13-
           There   are   two   existing   FBO   facilities     at   Hanscom.

Perscrutation of the record reveals appreciable support for the

proposition that a third FBO facility is needed.              For example,

Massport's 2005 draft environmental status and planning report

(ESPR), heavily relied on in the EA, supplies data indicating that,

even though the total volume of operations at Hanscom decreased

between 1990 and 2005, corporate aviation grew at a rate of 4.4

percent per year.3       Indeed, corporate aviation was "the only

segment of general aviation that [was] growing at Hanscom" during

that span.   The ESPR projected that this pattern of growth would

continue   through   2010   and   beyond.       The   ESPR   described   the

methodology underlying its projections, and Massport compared the

projections for 2005 with actual data for that year.          The trend was

evident: corporate aviation was experiencing continued growth at

Hanscom, "which would increase the demand for [general aviation]

hangars and associated facilities."

           The ESPR also provided background information linking

this trend to the need for a new FBO facility.         Among other things,

it related that "the majority of FBO activity involves servicing

corporate general aviation activity," creating a link from its

corporate aviation growth predictions to the need for a third FBO



     3
       An agency is free to rely in part on relevant, previously
conducted studies when preparing an EA. See Save Our 

; Conservation Law Found. v. Fed. Hwy. Admin., 

, 1473 n.1 (1st Cir. 1994).

                                  -14-
facility.    The FAA built on this information, noting in the EA that

"FBO capacity is not monolithic" and that "FBOs most frequently try

to differentiate their services from those of their competitors"

by, say, specializing in servicing a particular type of aircraft.

The FAA's explanation that the apron and hangar facilities at the

two existing FBO sites "have inadequate storage capacity for larger

. . . aircraft" illustrates the pertinence of this conclusion.

            In an effort to blunt the force of these data points, the

petitioners insist that general aviation operations at Hanscom are

in decline.      This statistic misses the mark: the proposed FBO

facility is not tethered to an anticipated increase in general

aviation    activity   as   a    whole   but,   rather,    to   an   anticipated

increase in the narrower subset of corporate jet operations.                Such

an anticipated increase is adequately documented.

            To say more on this point would be supererogatory. Given

the substantial evidence of a need for the Hangar 24 project, we

conclude that the FAA's rejection of the "do nothing" alternative

as imprudent was neither arbitrary nor capricious.                   After all,

doing nothing would fail to provide additional FBO services at

Hanscom (and, thus, would fail to meet a demonstrated need).

                            b.    The East Ramp.

            In   its   alternatives      analysis,   the   FAA   rejected    the

possibility of locating a new FBO facility elsewhere at Hanscom.

A major drawback of this alternative is that "Hanscom Field is


                                      -15-
approaching build-out," leaving only the East Ramp and Hangar 24 as

available sites for general aviation improvements.                As between

these two options, the FAA determined that locating the new FBO

facility on the East Ramp "would not be the most efficient use of

space" because of the ramp's distance from the terminal area and

the other two FBO facilities.       Furthermore, "using the East Ramp

for the FBO function . . . would preclude this area from being

developed for general aviation aircraft hangars that are already

located in this area of the airport."

            The FAA had other worries.          The agency found the East

Ramp alternative plagued by access problems, because it could not

be reached without passing through a secure military facility.

Massport was wary of this potential problem and investigated

various road reconfiguration layouts that might help to alleviate

it.    None of those routes provided an obvious solution; each would

require an easement of some sort, and many would pass over natural

features    such    as   rivers   and     wetlands,    creating    potential

environmental issues.      What is more, the EA expresses a concern

that    potential   developers    would    be   less   enthusiastic    about

constructing an FBO facility in such a remote area of the airport,

possibly preventing the completion of the project.

            Based on this collocation of factors, the FAA concluded

that it would be more prudent to build the new FBO facility at

Hangar 24 and use the East Ramp for general aviation aircraft


                                   -16-
hangars.      This was a judgment call — and one that fell within the

purview of the FAA's expertise.             The FAA's determination as to

whether a given alternative is prudent must be informed by the

statutory dictates that "the safe operation of the airport and

airway system is the highest aviation priority" and that "airport

construction and improvement projects that increase the capacity of

facilities to accommodate passenger and cargo traffic be undertaken

to the maximum feasible extent so that safety and efficiency

increase and delays decrease."        49 U.S.C. § 47101(a)(1), (7); see

City of Bridgeton v. FAA, 

, 462 (8th Cir. 2000)

(expressing "doubt whether [section 4(f)] mandates a rigid least-

harm standard in airport expansion cases," because such an approach

would be at odds with the "congressional mandate" prioritizing

safety and efficiency in airport operations); see also Citizens

Against Burlington, Inc. v. Busey, 

, 196 (D.C. Cir.

1991).

              The petitioners concede that there is no site at Hanscom,

other than the East Ramp, that might be a viable alternative to the

Hangar 24 site.       But they claim that the FAA's evaluation of the

East Ramp alternative fails adequately to quantify the supposed

inefficiencies, lacks specifics regarding the terminal distance

differential, and includes insufficient documentation of the access

problem.      In support, they cite Stop H-3 Ass'n v. Dole, 

  (9th    Cir.   1984),   a   case   purportedly   standing   for   the


                                     -17-
proposition that such a level of detail is required before a

feasible alternative may be discarded as imprudent.

          The record refutes this claim.      The FAA did not rely on

taxi distance or access impediments alone to justify its decision

but,   rather,   cited   the   combined    effect   of   a   number    of

considerations which weighed heavily against the East Ramp as a

safe and efficient FBO site.    An agency legitimately may invoke an

accumulation of factors to rule out an alternative as imprudent.

See Comm. to Pres. Boomer Lake Park v. Dep't of Transp., 

, 1550 (10th Cir. 1993); see also Eagle 

("A prudent judgment by an agency is one that takes into account

everything important that matters.      A cumulation of small problems

may add up to a sufficient reason to use § 4(f) lands.").      Even the

Stop H-3 court acknowledged the salience of this principle.           

.

          In the last analysis, "it is up to those who assail [the

agency's] findings or reasoning to identify the defects in evidence

and the faults in reasoning."    Save Our 

.

The petitioners have not carried this burden.       Although they decry

the FAA's appraisal of the East Ramp alternative, the FAA has

presented a compelling articulation of the factors that contributed

to its decision.    The petitioners have not offered the "sustained

and organized rebuttal," 

be necessary to invalidate

this articulation.


                                 -18-
                              c.    Adaptive Reuse.

           We    come   now    to     the    FAA's    evaluation   of    the   third

alternative: the possibility of adapting Hangar 24 to accommodate

the FBO project.        The FAA explained that "this alternative has

significant disadvantages because of the hangar's poor condition,

relatively small size, and functional inadequacy."                      The size of

both the building and the doorway aperture would have to be

increased dramatically in order to outfit the hangar for use by

larger aircraft.

           Enumerating        these    and    other    considerations,      the   EA

concluded that adaptive reuse "is expected to require substantial

and impractical building modifications to allow the building to

function   for    its   intended       use    and    bring   the   building     into

compliance with current environmental, structural, fire, safety,

and energy codes."       This conclusion was reinforced by the HNTB

study, which reported that any reconfigured version of Hangar 24

"would be inefficient to use and maintain . . . and unusable as a

hangar."   The study also noted that refurbishing Hangar 24, which

"may or may not be structurally feasible," would cost some $500,000

more than the estimated cost of constructing a brand new facility.

           In rebuttal, the petitioners assert that there is no data

showing that Hangar 24 would require enlargement.                  This assertion

is at best a half-truth; it is premised on the hypothesis that

there is no demonstrated demand for facilities that can accommodate


                                        -19-
larger aircraft.       This hypothesis is a slight variation on a

previously rejected theme, 

Part II(A)(1)(a), but the

variation is immaterial. As we have explained, the record contains

substantial support for the assertion that demand for FBO services

at Hanscom is likely to continue to increase.        The record likewise

reveals   that   the   two   existing   FBO   facilities   cannot   readily

accommodate larger aircraft, and it further notes that the existing

Hangar 24 structure is too small to be compatible with G5 business

jets.     This information is sufficient to undergird the FAA's

conclusion that enlargement of Hangar 24 would be required in any

sensible reuse scenario.

           As evidence of the viability of adaptive reuse, the

petitioners seize upon a suggestion that it might be feasible to

raise the roof of Hangar 24 without demolishing the building.           In

support, they note that the roof had been raised once before and

that the agency did not respond to this possibility (which first

surfaced during the comment period).             An agency is under no

obligation to respond individually to each and every concern raised

during the comment period.        See Conservation Law Found. of New

Engl., Inc. v. Andrus, 

, 717 (1st Cir. 1979).             Here,

moreover, the comment was not so compelling as to demand a direct

response given the building's overall condition and structural

deficiencies.     See 40 C.F.R. § 1508.9(a) (describing EA as "a

concise public document" (emphasis supplied)).


                                   -20-
           The petitioners' critique of the FAA's adaptive reuse

analysis gains no traction from a claimed inconsistency between the

FAA's conclusion that Hangar 24's door height would have to be

increased and Massport's commitment to maintaining an unobtrusive

building profile when redeveloping the site.                There is simply no

reason to believe that a door-height increase would necessarily

result in a building incompatible with surrounding structures.                In

the absence of concrete evidence to that effect, such conjecture is

insufficient      to    undermine   the     FAA's    finding    regarding    the

imprudence of adaptive reuse.        See Save Our 

("Gauzy generalizations and pin-prick criticisms, in the face of

specific findings and a plausible result, are not even a start at

a serious assault.").

           We add that even if none of the factors cited by the FAA,

standing alone, would justify its finding that adaptive reuse is

imprudent, that finding would still be supported by the totality of

the factors.      In making judgment calls of this sort, an agency is

both   entitled    and    obliged   to    consider    the    totality   of   the

circumstances.         See, e.g., Eagle 

.             The

whole is sometimes greater than the sum of the parts, and the

considerations limned in the EA, taken together, provide a reasoned

basis, adequately anchored in the administrative record, upon which

the FAA could conclude — as it did — that adaptive reuse is not a

prudent alternative.


                                     -21-
              There is one loose end.        As discussed in the EA and as

considered during the consultation period, the reuse alternative

encompassed a proposal that Hangar 24 be converted into an aviation

museum.      The FAA discussed this option "because of the significant

interest expressed on the part of consulting parties and the

public."      Though the proposal was sufficiently broad to include a

number of potential museum developers, one of the most likely

candidates — the Massachusetts Air and Space Museum — had already

declared the site unsuitable.         Ultimately, the agency rejected the

museum possibility because such a use would not address perceived

transportation      needs     and   would    present   significant      security

concerns that made it "undesirable and impractical."               We find no

error in this determination.         See 49 U.S.C. § 47101(a)(1) ("[T]he

safe operation of the airport and airway system is the highest

aviation priority . . . ."); see also Back 

.

              That ends this aspect of the inquiry.          In this context,

prudence is largely a matter of safety and efficiency; and the

FAA's determination that none of the three alternatives would be

prudent was, on the record before it, well within the universe of

reasonable outcomes.        When that is true, it is not the place of a

reviewing court to second-guess the agency.

              2. Minimization of Harm. Once an agency determines that

there   is    no   feasible   and   prudent    alternative   to   the    use   of

protected land, section 4(f) requires it to consider whether the


                                      -22-
proposal at hand "includes all possible planning to minimize harm."

49 U.S.C. § 303(c)(2).         An agency determination that a submitted

plan sufficiently minimizes the likely harms to historic properties

must   be   treated    respectfully      by   a    reviewing     court.      Such

determinations      "deserve    even     greater    deference      than    agency

determinations concerning practicable alternatives." Conservation

Law Found. v. Fed. Hwy. Admin., 

, 1476-77 (1st Cir.

1994); see Concerned Citizens Alliance, Inc. v. Slater, 

, 702 (3d Cir. 1999).

            The petitioners insist that the FAA should postpone the

demolition of Hangar 24 until after the design, permitting, and

financing of the new FBO facility are in place, thus leaving open

the possibility that the facility might incorporate the existing

hangar.      We    reject     these     importunings.       When     discussing

minimization, the FAA specifically noted that "reuse of Hangar 24

as a hangar is neither prudent nor practical."                   The FAA fully

addressed    the    adaptive    reuse    approach     in   its    analysis    and

supportably determined that this approach was imprudent.                  No more

was exigible.      An agency need only consider harm-minimizing steps

that are feasible and prudent under existing circumstances.                  Back

.        A few explanatory comments may be helpful.

            Section 4(f)(2)'s requirement that a project include

planning to minimize harm to historic sites does not demand that an

agency, having already ruled out an option as imprudent under


                                       -23-
section 4(f)(1), circle back to reconsider that option as a means

of mitigating harms.     Instead, the 4(f)(2) inquiry is focused on

means of minimization that are compatible with the alternative or

alternatives deemed feasible and prudent under 4(f)(1).

            Congress established a very rigorous, time-consuming

administrative process through which projects that might affect

protected   historic    sites    are    reviewed   and,      if   appropriate,

approved.      This    administrative        process    is    geared    toward

consideration of the project concept itself, regardless of which

developer may ultimately carry the proposal to fruition.                     Of

course, should the parameters of the project change materially,

additional administrative approvals will likely be necessary.                But

so long as the project's scope remains within the general contours

of the proposal reviewed and approved by the agency, the validity

of its approval is not conditioned on the presence or absence of a

developer prepared to move forward with the construction.

                                 B.    NHPA.

            Section 106 of the NHPA requires that federal agencies

"take into account the effect of [an] undertaking on any district,

site,   building,   structure,    or    object   that   is   included   in   or

eligible for inclusion in the National Register."                   16 U.S.C.

§ 470f.   It also directs that agencies "shall afford the Advisory

Council on Historic Preservation . . . a reasonable opportunity to

comment."    

"[s]ection 106 is a procedural statute


                                      -24-
that requires agency decisionmakers to 'stop, look, and listen,'

but not to reach particular outcomes."         Back 

(quoting Narragansett Indian Tribe v. Warwick Sewer Auth., 

, 166 (1st Cir. 2003)).

           Congress      created   the   Advisory   Council    on    Historic

Preservation (the Council) to administer the NHPA.            See 16 U.S.C.

§§ 470i, 470s.     The Council has promulgated regulations to guide

agencies in performing their obligations under the statute. See 36

C.F.R. pt. 800.    These regulations direct agencies to determine if

a project qualifies as an "undertaking" that "has the potential to

cause effects on historic properties."        

      If so, the

agency must consult with the state historic preservation officer

(SHPO) to "[d]etermine and document the area of potential effects."

see 

      The agency, along with the

SHPO, is then directed to "apply the National Register criteria" to

arguably eligible sites within the area of potential effects.             

     If the agency finds that historic sites may be

affected, it must solicit the views of various parties.                   

    The agency then applies the criteria delineated in

the regulations to determine if there is an effect or effects, 

and if so, engages in further consultation to resolve

any such effects, 

           This step involves notifying the Council so that it can

decide   whether   its    continued    participation   is   desirable,    

800.6(a)(1), and looking at alternatives that might "avoid,

minimize or mitigate the adverse effects," 

(b)(2).   If the agency and the consulting parties agree on a means

of abating the effects, they must execute a memorandum of agreement

(the Memorandum).    

(b)(2).          The Memorandum

"evidences . . . compliance with section 106" and the regulations.

           In the case at hand, NHPA consultation began in April of

2008, when the FAA informed the Commission (the relevant state

entity) that the Hangar 24 project was an "undertaking" within the

purview   of   the   regulations.          The   FAA   concurred   with   the

Commission's finding that the hangar was eligible for listing on

the National Register under Criteria A and B.              The FAA and the

Commission then defined the project's area of potential effects to

include the footprint of the hangar and its appurtenances.

           In December of 2008, the FAA issued a draft EA, which was

made available for public comment.               The Council reviewed this

document and determined that its "participation in the consultation

to resolve adverse effects [was] unnecessary."            According to the

Council, the EA's discussion of alternatives was "exhaustive," and

the Commission fully concurred with the FAA's findings about the

project's effects (and lack of effects) on historic properties.

The FAA proceeded to prepare a draft Memorandum to memorialize its

commitments to mitigation and circulated the Memorandum to the


                                    -26-
consulting parties for their input.            The final EA responded to

comments and included a final version of the Memorandum.

            The petitioners advance a salmagundi of arguments as to

why the NHPA requirements were not satisfied. To begin, they argue

that, because the area of potential effects was determined "without

reference to any specific development proposal," that determination

is inconsistent with the regulatory directive that the area's scope

should be "influenced by the scale and nature of an undertaking."

     It is true that when the EA was prepared, there

was no developer lined up to proceed with FBO facility construction

and, thus, no definitive set of development plans existed.                    But

Massport had previously reviewed proposals and selected a plan for

the site, thus evincing that it had a particular set of criteria in

mind.   The concept was clearly delineated.

            NHPA's    implementing     regulations     direct      agencies    to

"ensure that the section 106 process is initiated early in the

undertaking's planning, so that a broad range of alternatives may

be considered."      

     This directive makes it pellucid

that agencies are not expected to delay NHPA review until all

details of the proposal are set in cement.            Of course, should the

project's   scope    change   in   some    material   way   when    a   specific

developer is identified, additional FAA approvals may be required.

But the proposal here was sufficiently well-defined to trigger the

NHPA review process.


                                     -27-
           Taking a different tack, the petitioners say that the FAA

erred in determining that the area of potential effects did not

encompass any historic sites beyond Hangar 24 itself.                  This is

whistling past the graveyard; the record reveals beyond hope of

contradiction that the FAA examined the possibility of effects on

other sites and supportedly concluded that none of the alternatives

would have an effect — either direct or indirect — on any protected

historic venue (apart from Hangar 24 itself).

           Relatedly, the petitioners fault the FAA for neglecting

to take into account, when defining the area of potential effects,

the possibility that the project would alter views from nearby

sites and, in the bargain, create a fire hazard attributable to

fuel   storage.   But   the    2005      ESPR   noted   that,   due   to   local

topographical features, the airport was not visible from most

nearby   locations;   and     in   any    event,   Massport     committed    to

maintaining building dimensions that would "be respectful of views

from off-site vantages."           Finally, in its response to public

comments appended to the EA, the FAA explained that the State Fire

Marshal's Office will regulate fuel storage at any new structure

and that other measures for the containment of fuel-related hazards

had been contemplated. Regardless of whether the petitioners agree

with the FAA's conclusions about these matters, they have failed to

show that the conclusions are arbitrary or capricious.




                                     -28-
           The     petitioners'     next    plaint    is    equally       without

foundation.      Although   they    express   concern      that    the   new    FBO

facility   would    indirectly     affect   noise    levels       by   attracting

additional jet traffic, the FAA explained in the EA why that

scenario is unlikely to occur.        There, it stated that, consistent

with its mandate to provide "a safe and efficient national airspace

system," the FBO project was intended "to meet forecasted demand

for adequate facilities" for corporate aircraft at Hanscom.                    This

articulated purpose was aimed at meeting an increase in demand that

the record confirms will likely take place independent of any

improvements at Hanscom; it was not calculated to drive an increase

in traffic.

           In light of the FAA's observation that improvements to

infrastructure are not typically sufficient, on their own, to

attract new activity to an airport, the record is barren of any

basis for the expectation that the new FBO facility will cause any

increase in traffic.        In the absence of such an evidentiary

predicate, it was entirely logical for the FAA to conclude that the

contemplated FBO facility would produce no meaningful increase in

noise levels.    Cf. Save Our 

(upholding

FAA finding that impacts of newly authorized flights were de

minimis under NHPA and NEPA standards).

           If more were needed — and we doubt that it is — we note

that, notwithstanding its determination that the potential for


                                    -29-
increased noise was not a problem, the FAA went the extra mile; it

made a "worst case" calculation.      While the agency was under no

obligation to make a worst case calculation in light of its no-

effects finding, cf. Robertson v. Methow Valley Citizens Council,

, 356 (1989) (explaining that NEPA analysis should

"focus on reasonably foreseeable impacts" and that no "worst case

analysis" is required), the results of that calculation reinforced

its position.

          Switching gears, the petitioners urge that because Walden

Pond (a national historic landmark) is nearby, the FAA was required

to comply with the heightened standards that pertain to such sites.

See 16 U.S.C. § 470h-2(f); 36 C.F.R. § 800.10.      Given the FAA's

warranted determination that there would be no effects on nearby

historic sites, the agency was under no obligation to move to this

more intensive level of review.    See Back 

.

          The petitioners have one last grievance addressed to the

FAA's NHPA compliance.   They argue that the FAA and the Commission

blundered in finding that Hangar 24 was ineligible for listing on

the National Register under Criterion C, which applies to sites

that embody distinctive architectural characteristics.      See 36

C.F.R. § 60.4(c).   This grievance is baseless.

          To be sure, the criteria used to determine whether a site

qualifies for listing on the National Register will inform the

choice of appropriate mitigation measures. Here, however, there is


                               -30-
ample   evidence     in   the   record     to   show    that      the    FAA   and    the

Commission fully considered the applicability vel non of Criterion

C.    To this end, the Commission observed, in correspondence to the

FAA, that Hangar 24 was "deteriorated" and had been "cleared of its

historical scientific instrumentation, equipment, research files,

and furnishings."         In a return letter, the FAA confirmed its

awareness of "new information" pertinent to Criterion C proffered

by the Concord Historical Commission and found that this proffer

contained no insights beyond those previously considered.

            The short of it is that the petitioners, despite their

kaleidoscopic array of attacks, have not shown noncompliance with

any of the procedures mandated by the NHPA and its implementing

regulations.       Nor have they shown that the FAA failed to satisfy

its   obligation     to   weigh    effects.        While    the    petitioners        may

disagree    with    the    FAA's    calibration        of   these        scales,     that

disagreement, in itself, is insufficient to scuttle the FAA's

findings.

                                    C.    NEPA.

            The    NEPA    requires      federal    agencies        to    prepare     an

environmental impact statement (EIS) for "major Federal actions

significantly affecting the quality of the human environment."                         42

U.S.C. § 4332(2)(C).       Where the need for an EIS is not obvious, an

agency may instead prepare an EA.           40 C.F.R. § 1501.4(b).             An EA is

meant to be less detailed than an EIS.             See, e.g., United States v.


                                         -31-
Coal. for Buzzards Bay, ___ F.3d ___, ___ (1st Cir. 2011) [No. 10-

1664, slip op. at 11].      If the agency, based on the EA, determines

that an EIS is not needed, it may issue an explained finding of no

significant impact.    40 C.F.R. § 1501.4(c), (e).         The requirements

imposed by the NEPA are procedural in nature and are not intended

to dictate any particular substantive outcome.         Pub. 

; 

.

          The petitioners' NEPA challenge focuses on the FAA's

consideration   of    the    potential    to    increase    noise   levels.

Specifically, the petitioners upbraid the FAA for failing properly

to quantify cumulative noise impacts.          The applicable regulations

define cumulative effects as "the incremental impact of the action

when added to other past, present, and reasonably foreseeable

future actions."     40 C.F.R. § 1508.7.

          This lament does not withstand scrutiny.              The record

shows that the FAA considered all the relevant factors.                 It

identified the only other reasonably foreseeable development (that

anticipated for the East Ramp) and added anticipated noise from

that project, calculated at 0.3 dB, to a predicted maximum noise

increase of 0.2 dB from the Hangar 24 project.         The 2008 East Ramp

noise study upon which the FAA based its worst case calculation

took account of total noise levels in the area.               It added the

projected increase for the East Ramp development to preexisting

baseline noise conditions.      See League of Wilderness Defenders v.


                                   -32-
U.S. Forest Serv., 

, 1217 (9th Cir. 2008).        The FAA

generally regards as significant a decibel increase of 1.5 dB or

greater (based on a day-night average) at or above a 65 dB noise

exposure level.    FAA Order 1050.1E, CHG 1, App. A, para. 14.3 (Mar.

20, 2006).    The foreseeable increase here fell comfortably within

that range.      We conclude, therefore, that the FAA's exercise

constituted a reasonable approach to the potential problem. And as

a further check, the FAA "carefully reviewed" the 2005 ESPR's

analysis of the projected cumulative noise and air quality effects

of both the Hangar 24 and the East Ramp projects.4

          The     petitioners   calumnize   the   FAA's   decision   to

extrapolate from prior studies rather than commission a new study

for Hangar 24.     In our view this decision was not unreasonable,

especially given the agency's prediction, based on the FAA's

experience with other airport projects, that the Hangar 24 project

was unlikely to have any impact at all on noise levels.       We hold,



     4
       The petitioners point out that the FAA's own internal
guidance acknowledges that the "65 dB threshold does not adequately
address the effects of noise on visitors to areas within a national
park . . . where other noise is very low and a quiet setting is a
generally recognized purpose and attribute." FAA Order 1050.1E,
CHG 1, App. A, para. 14.3.       This guidance does not help the
petitioners. Although Hanscom is located in close proximity to at
least one historic national park, the petitioners have proffered no
evidence that any such park is specifically recognized for its
tranquility. See, e.g., 16 U.S.C. § 410s(a) (establishing Minute
Man National Historical Park and describing its purposes). For
that matter, the petitioners have proffered no evidence showing a
need for special noise level protection at any place in the
vicinity.

                                 -33-
therefore, that the FAA's noise impact calculations are impervious

to the petitioners' challenge.

           Of course, if and when Massport chooses to proceed with

additional development at Hanscom, that work may require additional

FAA approvals.       But the NEPA requires a cumulative analysis only

"to ensure that a project is assessed as a whole and not sliced

into 'small component parts.'" Town of Marshfield v. FAA, 

, 4 (1st Cir. 2008) (quoting 40 C.F.R. § 1508.27(b)(7)).             For NEPA

purposes, an agency need not speculate about the possible effects

of future actions that may or may not ensue.           See, e.g., Coal. on

Sensible Transp., Inc. v. Dole, 

, 69 (D.C. Cir. 1987).

III.   CONCLUSION

           We   need    go   no   further.   A    careful   reading    of   the

administrative record shows with conspicuous clarity that the FAA

was cognizant of, and complied with, its responsibilities under the

applicable statutes and regulations.              The conclusions that it

reached, though not inevitable, are adequately grounded and in

accordance    with    law.    Accordingly,   we    deny   the   petition    for

judicial review.



So Ordered.




                                     -34-