The Endangered Species Act: A Primer






Prepared for Members and Committees of Congress



The Endangered Species Act (ESA) protects species identified as endangered or threatened with
extinction and attempts to protect the habitat on which they depend. It is administered primarily
by the Fish and Wildlife Service, and by the National Marine Fisheries Service for certain marine
and anadromous species. Dwindling species are listed as either endangered or threatened
according to assessments of the risk of their extinction. Once a species is listed, legal tools are
available to aid its recovery and to protect its habitat. The ESA can become the visible focal point
for underlying situations involving the allocation of scarce or diminishing lands or resources,
especially in instances where societal values may be changing, such as for the forests of the
Pacific Northwest, the waters in the Klamath River Basin, or the polar environment. This report
discusses the major provisions of the ESA, both domestic and international, and also discusses
some of the background issues, such as extinction in general, and the effectiveness of the statute.
The discussion is expanded for four aspects of the ESA and its implementation that have raised
concerns and promoted debate—listing species, designating critical habitat, consulting on
projects, and exempting projects. This report provides much of the context for understanding
individual legislative initiatives discussed in CRS Report RL33779, The Endangered Species Act th
(ESA) in the 110 Congress: Conflicting Values and Difficult Choices, by Eugene H. Buck et al.
This report will be updated as circumstances warrant.






Overvi ew ....................................................................................................................... .................. 1
What Is the ESA?......................................................................................................................1
Why Is the ESA Controversial?................................................................................................1
Has ESA Been Effective?..........................................................................................................2
Leading Causes of Extinction...................................................................................................3
Is Extinction Normal?...............................................................................................................3
Major Provisions of Current Law: Domestic..................................................................................4
Endangered and Threatened Species.........................................................................................4
“Take” ....................................................................................................................................... 5
FWS and NMFS........................................................................................................................5
Listings ...................................................................................................................................... 5
Candidate Species.....................................................................................................................6
Delisting and Downlisting.........................................................................................................6
Critical Habitat..........................................................................................................................6
Recovery Plans..........................................................................................................................7
Land Acquisition.......................................................................................................................7
Cooperation with States............................................................................................................7
Consultation .............................................................................................................................. 8
Exemptions ................................................................................................................................ 8
Emerge ncies ........................................................................................................................ 9
Permits for Non-Federal Actions...............................................................................................9
Other Provisions........................................................................................................................9
Prohibitions and Penalties.......................................................................................................10
Major Provisions of Current Law: International...........................................................................10
Financial Assistance................................................................................................................10
CITES Scientific Authority.....................................................................................................10
CITES Management Authority.................................................................................................11
Vi ol ations ................................................................................................................................. 11
Imports/Exports ........................................................................................................................ 11
Particular Species.....................................................................................................................11
Analysis of Domestic Law Provisions..........................................................................................12
Listing ..................................................................................................................................... 12
Bases for Listings..............................................................................................................12
Pre-Listing Activities........................................................................................................14
Special Rules for Threatened Species...............................................................................15
Distinct Population Segments...........................................................................................15
Experimental Populations.................................................................................................16
Designation of Critical Habitat...............................................................................................16
Post-Listing Activities: Consultation......................................................................................18
Exemption Process: A History.................................................................................................19
The Endangered Species Committee................................................................................19
Eligible Applicants............................................................................................................20
Secretarial Review............................................................................................................21
Committee Determination.................................................................................................21
Mitigation..................................................................................................................... ..... 22
Special Circumstances......................................................................................................22





Duration and Effect of Exemption....................................................................................23
Appendix. Exemption Applications...............................................................................................24
Author Contact Information..........................................................................................................25





he Endangered Species Act (ESA)1 receives significant congressional attention. The
associated power and reach of its comprehensive protection for species identified as
endangered or threatened with extinction has ignited concern that there be greater bounds T


on this power, and fanned the flames over assertions of lax implementation of its power. The
following discussion provides an overview and background on the various features of the ESA
that contribute to its stature and yet spark an ongoing debate over its implementation.

The ESA is a comprehensive attempt to provide legal protection to identified species and to
consider habitat protection as an integral part of that effort. It is administered primarily by the 23
Fish and Wildlife Service (FWS), but also by the National Marine Fisheries Service (NMFS) for
certain marine species. Under the ESA, species of plants and animals (both vertebrate and
invertebrate) are listed as either “endangered” or “threatened” according to assessments of the
risk of their extinction. Once a species is listed, powerful legal tools are available to aid the
recovery of the species and to protect its habitat. As of April 16, 2008, a total of 1,925 species of
animals and plants had been listed as either endangered or threatened; 1,351 of these occur in the 4
United States and its territories and the remainder only in other countries. Of the U.S. species, 5
1,156 are covered by recovery plans. The authorization for funding under ESA expired on
October 1, 1992, although Congress has appropriated funds in each succeeding fiscal year.
While the ESA plays an important role in protecting species, it can also become a surrogate
battleground in quarrels whose primary focus is the allocation of scarce or diminishing lands or
resources. Indeed, a stated purpose of the ESA is to “provide a means whereby the ecosystems 6
upon which endangered species and threatened species depend may be conserved.” The
surrogate role is especially likely because other laws often lack the strict substantive provisions
that Congress included in the ESA (see “Major Provisions” sections, below). There can be
economic interests on all sides of some vanishing species issues. Like the miners’ canaries
signaling a scarce resource (safe air supply), declining species are often symptoms of resource
scarcities and altered ecosystems. Examples of such resource controversies include the Tellico
Dam (hydropower development and construction jobs versus farmland protection and tribal
graves, as well as the endangered snail darter); Northwest timber harvest (protection of logging
jobs and communities versus commercial and sport fishing, recreation, and ecosystem protection,

1 Act of December 28, 1973, P.L. 93-205, 87 Stat. 884. 16 U.S.C. §§ 1531-1544.
2 For detailed information on the FWS program for endangered species, see the FWS website at http://www.fws.gov/
endangered/.
3 NMFS, a part of the National Oceanic and Atmospheric Administration, is also sometimes referred to as NOAA
Fisheries.
4 For updated information, see http://ecos.fws.gov/tess_public/Boxscore.do.
5 Ibid.
6 16 U.S.C. § 1531(b).



as well as salmon and spotted owls); and oil development on the energy-rich plain around the
northern mountain states (coal bed methane development, grazing rights, ground water protection,
traditional ranching, and a proposal for sage grouse listing in a complex and varying stew of 7
interests). And the worldwide debate over global warming has found its avatar in the polar bear.
In recent years, tensions over the ESA have increased as species have been added to the protected
list, and as the greater demands of a growing economy and human population have affected
species’ habitats. Both Congress and the Executive Branch have sought to lessen these tensions
by, among other things, tailoring application of the ESA for particular circumstances. The ESA’s
critics contend that neither the ESA nor administrative efforts go far enough in accommodating
needs other than species conservation, while the ESA’s defenders counter that it merely balances
an inherent bias toward development in other governmental laws and policies.
Debate, pro and con, on the ESA splits largely along demographic lines. While most demographic
groups support species conservation to some degree, that support is stronger among urban and
suburban populations and less so in rural areas, and is stronger among those in the East and along
the coasts and less so in central and mountain states. Sport hunters and anglers seem divided on
the issue. Native Americans, as a group often dependent on natural resources (e.g. fish), are
frequently involved in ESA issues, most commonly siding with survival of listed species. Groups
opposing strong protections for listed species usually make claims that jobs will be lost if
conservation measures are stringent, but those seeking strong protections often claim that jobs
will be lost if they are not. It is also noteworthy that, while the debate often centers on jobs and
biology, people on both sides claim ethical support for their positions, and many religious groups
now participate in the debate. In addition, some industries (e.g., logging and land development)
generally see the ESA as a serious problem, while others (e.g., some commercial fishing and
many recreation interests) see it as generally supporting their interests.
The answer to this question depends very much on the choice of measurement. A major goal of
the ESA is the recovery of species to the point at which the protection of the ESA is no longer
necessary. If this is the standard, the ESA might be considered a failure, since only 22 species 8
have been delisted due to recovery, as of April 16, 2008. Nine species have become extinct since 9
their listing, and 17 have been delisted due to improved data or scientific understanding. In the
former case, some of the nine species now believed extinct were originally listed to protect any
last remaining few that might have been alive at the time of listing. It can be quite difficult to
prove whether extraordinarily rare species are simply that, or in fact are already extinct. For
example, a rare shorebird thought by many to be extinct was re-discovered in a remote area of
Canada a few years ago; it might just as easily have quietly gone extinct without being
rediscovered. Rare species are, by definition, hard to find.

7 Ultimately, a petition to list this species was judged not to be warranted. The interests mentioned here, and many
others, had a variety of goals in supporting or opposing the listing proposal. For details, see http://www.r6.fws.gov/
species/birds/sagegrouse/.
8 See http://ecos.fws.gov/tess_public/DelistingReport.do to obtain updated information. The recovered species include
the bald eagle in the lower 48 states and the Yellowstone area population of grizzly bears.
9 Ibid.





Even so, since some scientific studies demonstrated that most species are listed only once they are
very depleted (e.g., median population of 407 animals for endangered vertebrates according to
one study), another measure of effectiveness might be the number of species that have stabilized
or increased their populations, even if the species is not actually delisted. If this is the standard,
the ESA could be considered a success, since a large number (41% of listed species according to 10
one study) have improved or stabilized their population levels. Other species (e.g., red wolves
and California condors) might not exist at all without ESA protection, and this too might be
considered a measure of success, even though the species are still rare. One could also ask what
species might have become extinct if there were no ESA. The authors are unaware of
comprehensive studies regarding the likely status of rare species were there no ESA, but for
species such as spotted owls, salmon, Florida panthers, and plants of very narrow ranges, it seems
likely that their numbers would be (at best) far fewer if ESA did not exist.
Until recent decades, the focus of the extinction debate was on losses due to over-exploitation,
generally through hunting, trapping, or fishing. The poster species of the debate were passenger th
pigeons, tigers, wolves, and other well-known animals. But during the 20 century, a shift of
focus and probably of fact occurred. The vast majority of species, including those for which
direct taking was probably an early factor in their decline, are generally also at risk due to habitat
loss. Habitats reduced now to a small fraction of their former extent include tall-grass prairie,
fresh and salt water wetlands, old growth forests of most types, free-flowing rivers, coral reefs,
undisturbed sandy beaches, and others.
Another high-ranking factor in the demise of many species is the introduction of non-native
species. The non-native (invasive) species can be disease vectors or parasites (e.g., avian malaria
in Hawaii, or Asian long-horned beetles in North America), predators (brown tree snakes in Guam
and Hawaii), or competitors (e.g., barred owls in the Pacific Northwest). The gradual 11
homogenization of the world’s flora and fauna has led to a demise of many species.
If extinction is normal, some argue that there is no need for the government to intervene to halt
this natural process. But is it normal? Geological evidence shows that the vast majority of species
that have ever lived on Earth are now extinct—an observation uncontested by paleontologists.
However, many scientists are concerned that the current rate of extinction exceeds background 12
extinction rates over time. But calculating current rates of extinction, much less making
comparisons with the geologic past, is extremely difficult. Current estimates of total species range
from 3.5 million to 100 million, with 10-30 million being commonly accepted numbers. If

10 See CRS Report 98-32, Endangered Species List Revisions: A Summary of Delisting and Downlisting, by Robert J.
Noecker.
11 See CRS Report RL30123, Invasive Non-Native Species: Background and Issues for Congress, by M. Lynne Corn et
al.
12 Over the billions of years of life on Earth, extinction rates have varied, with five periods of exceptionally high rates.
The most famous periods are the mass extinctions at the end of the Age of Dinosaurs (Cretaceous Period), about 65
million years ago, and the even more massive die-offs at the end of the Permian Period, about 250 million years ago,
when about 52% of the groups of marine species became extinct. Between each of these five events, extinctions
continued at more moderate, background levels.





scientists are unsure of how many species exist, it is naturally difficult to estimate how fast they
are going extinct, and whether current extinction rates exceed background extinction rates.
Consequently, scientists use very conservative assumptions to make these estimates. The resulting
extinction rates (17,000 species per year being a typical estimate) still seem astonishingly large,
in part because the public is generally unaware of the huge number of species in groups to which
many people pay little or no attention (e.g., beetles, marine invertebrates, fish), and the large
number of species estimated on Earth. How do these compare to background rates?
Widely diverse methods all suggest that current rates of extinction exceed background rates.
Normal rates are thought to be from 1 to 10 species per every 10 million species per year. (That
is, if there are 20 million species now, background levels would be about 2 to 20 species
extinctions per year.) Common estimates of current extinction rates range from 100 to 10,000
times such background rates—roughly comparable to the five great episodes of extinction in the
geologic past. Critics most frequently question these calculations by stressing uncertainties, rather
than citing specific factual errors. This criticism is not surprising, since each step in these
calculations contains uncertainties (e.g., estimating the number of existing species). Most
biologists counter by noting that similar numbers are generated in studies of widely different
groups by a variety of scientists using different methods. Robust results (i.e., similar results from
the testing of a hypothesis in a variety of ways) are usually considered scientifically sound.
Once extinct, a species can never be revived. But, faced with high rates of extinction, some might
take comfort in a return to an equal number of species, even if those species are different.
Evolution continues, even in the face of high extinction rates, so perhaps new species will evolve
that are better adapted to new conditions. If so, how long would such a “recovery” take?
Examining the geologic record after major extinction episodes, some scientists estimate that
recovery to approximately equal numbers of (different) species took up to 25 million years for the
most severe extinction events. Thus, if the current extinction rate and recovery rate are
comparable to past rates, the return to species numbers of the pre-historic era would take several
million years.

The modern ESA was passed in 1973, but was preceded by simpler acts in 1966 and 1969. It has
been amended on numerous occasions since then: 1976, 1977, 1978, 1979, 1980, 1982, and 1988.
The following are brief summaries of the major domestic provisions of the ESA in the order they
appear in the U.S. Code. Several major issues are discussed in more detail later in this report.
An endangered species is defined as “any species which is in danger of extinction throughout all
or a significant portion of its range.... ” A threatened species is defined as “any species which is
likely to become an endangered species within the foreseeable future throughout all or a
significant portion of its range.” The ESA does not rely on a numerical standard: such a standard
would not reflect the wide variety of many species’ biology. (For example, a population of 10,000
butterflies, all confined to one mountaintop, would clearly be at greater risk than 10,000
butterflies scattered over thousands of square miles.) The protection of the ESA extends to all
species and subspecies of animals (not just birds and mammals), although for vertebrates, further
protection can be given for distinct population segments within a species, and not just the species





as a whole. More limited protection is available for plant species under the ESA.13 There is
currently no protection afforded under the ESA for organisms (e.g., Eubacteria, Archaea, viruses)
considered neither animal nor plant.
The term “take” under the ESA means “to harass, harm, pursue, hunt, shoot, wound, kill, trap, 14
capture, or collect, or to attempt to engage in any such conduct.” (Harassment and harm are
further defined by regulation at 50 C.F.R. § 17.3.) Taking is prohibited under 16 U.S.C. § 1538.
There has been controversy over the extent to which the prohibition on taking may include habitat 15
modification. A 1995 Supreme Court decision held that the inclusion of significant habitat
modification was a reasonable interpretation of the term “harm” in the law.
The Secretary of the Interior manages and administers most listed species through FWS. Marine
species, including some marine mammals, and anadromous fish are the responsibility of the
Secretary of Commerce, acting through NMFS. The law assigns the major role to the Secretary of
the Interior (all references to “Secretary” below are to the Secretary of the Interior unless
otherwise stated) and provides in detail for the relationship of the two Secretaries and their 16
respective powers.
Species may be listed on the initiative of the appropriate Secretary or by petition from an
individual, group, or state agency. The Secretary must decide whether to list the species based
only on the best available scientific and commercial information, after an extensive series of
procedural steps to ensure public participation and the collection of relevant information. At this
point, the Secretary may not consider the economic effects that listing may have on the area
where the species occurs. This is the only place in the ESA where economic considerations are 17
expressly forbidden; such considerations may enter in a later stage. Economic factors cannot be
taken into account at this stage, because Congress directed that listing be fundamentally a
scientific question: is the continued existence of the species threatened or endangered? Through
the 1982 amendments particularly, Congress clearly intended to separate this scientific question
from subsequent decisions on appropriate protection. This is evident upon comparing 16 U.S.C. §

1533(b) with § 1533(f) in this regard.



13 16 U.S.C. § 1538(a)(2).
14 16 U.S.C. § 1532.
15 Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, 515 U.S. 687 (1995) (“Sweet Home). See CRS
Report 95-778, Habitat Modification and the Endangered Species Act: The Sweet Home Decision, by Pamela Baldwin.
16 16 U.S.C. § 1533.
17 See CRS Report RL30792, The Endangered Species Act: Consideration of Economic Factors, by Pamela Baldwin,
for an analysis of when the ESA does allow consideration of such factors.





In the interval between a proposal and a listing decision, the Secretary must monitor the status of
these “candidate” species and, if any emergency poses a significant risk to the well-being of the 18
species, promptly list them. Some steps in the normal listing process may be skipped for
emergency listings. Federal agencies must confer with the appropriate Secretary on actions likely
to jeopardize the continued existence of candidate species, but agencies need not limit 1920
commitments of resources. As of April 16, 2008, there were 282 candidate species.
The processes for delisting or downlisting a species from the Lists of Endangered and Threatened 21
Wildlife and Plants are the same as the processes for listing. Delisting is removing a species
from the lists. Downlisting is reclassifying a species from endangered to threatened, and uplisting
is the reverse. The Secretary of the Interior may initiate a change in the status of listed species.
Alternatively, after receiving a substantive petition for any change in listing status, the Secretary
is to review the species’ status. The determination to delist, downlist, or uplist a species must be 22
made “solely on the basis of the best scientific and commercial data available” and “without 23
reference to possible economic or other impacts.” The statute and regulations also mandate that,
at least once every five years, there be a review of each listed species to determine whether it
should be removed from the list, changed from endangered to threatened, or changed from 24
threatened to endangered.
When a species is listed, the Secretary must also designate critical habitat (either where the 25
species is found or, if it is not found there, where there are features essential to its conservation).
If the publication of this information is not “prudent” because it would harm the species (e.g., by
encouraging vandals or collectors), the Secretary may choose not to designate critical habitat. The
Secretary may also postpone designation for as long as one year if the information is not 26
determinable. As of April 16, 2008, critical habitat had been designated for 509 listed species.
Any area, whether or not federally owned, may be designated as critical habitat, but private land
is only affected by critical habitat designation if some federal action (e.g., license, loan, permit) is

18 16 U.S.C. § 1533(b)(3)(C)(iii).
19 16 U.S.C. § 1536(a)(4). The limitation on commitments of resources originated in the debate over Tellico dam. (See
Appendix of this report.) As controversy over the dam raged in Washington and in Tennessee, the Tennessee Valley
Authority accelerated work on the dam, leaving the project nearly complete before the Endangered Species Committee
had met. (SeeExemption Process: A History, below.)
20 For updated information, see http://ecos.fws.gov/tess_public/SpeciesReport.do?listingType=C.
21 For more information on this topic, see CRS Report 98-32, Endangered Species List Revisions: A Summary of
Delisting and Downlisting, by Robert J. Noecker.
22 16 U.S.C. § 1533(b)(1)(A).
23 50 C.F.R. § 424.11(b).
24 16 U.S.C. 1533(c) and 50 C.F.R. § 424.21.
25 16 U.S.C. §§ 1533(a)(3) and (b)(2).
26 See http://ecos.fws.gov/tess_public/CriticalHabitat.do?listings=0&nmfs=1 for updated information.





also involved. Federal agencies must avoid “destruction or adverse modification” of critical 27
habitat, either through their direct action or activities that they approve or fund.
P.L. 108-138 added a provision28 specifying that the Secretary shall not designate critical habitat
on lands controlled by the Defense Department, if those lands are subject to an Integrated Natural
Resource Management Plan (INRMP) under the Sikes Act (16 U.S.C. § 670a). The provision was
subject to the Secretary’s determination, in writing, that the INRMP provided “a benefit” to the 29
lands which might otherwise have been designated as critical habitat. In addition, the Secretary
was directed to take national security into consideration in designating critical habitat. These
provisions were added in response to a perception that designated critical habitat on some military
lands interfered with military training and readiness activities.
The appropriate Secretary must develop recovery plans for the conservation and survival of listed 30
species. Recovery plans to date tend to cover birds and mammals, but a 1988 ESA amendment
prohibits the Secretary from favoring particular taxonomic groups. The ESA and its regulations
provide little detail on the requirements for recovery plans, nor are these plans binding on federal
agencies or others, and the essentially hortatory nature of these plans has been widely criticized. 31
As of April 16, 2008, recovery plans had been completed for 1,156 U.S. species.
Land may be acquired to conserve (recover) endangered and threatened species, and money from 32
the Land and Water Conservation Fund may be appropriated for this acquisition. In FY2005, a
total of 1,655 acres were acquired by FWS for the National Wildlife Refuge System under ESA
authority.
The appropriate Secretary must cooperate with the states in conserving protected species and
must enter into cooperative agreements to assist states in their endangered species programs, if 33
the programs meet certain specified standards. If there is a cooperative agreement, the states
may receive federal funds to implement the program, but the states must normally provide a
minimum 25% matching amount. The 1988 ESA amendments created a fund to provide for the
state grants, including land acquisition and planning assistance. While the authorized size of the
fund is determined according to a formula, money from the fund still requires annual

27 16 U.S.C. § 1536(a)(2).
28 16 U.S.C. § 1533(a)(3)(B).
29 The military remains subject to ESAs provisions other provisions, including consultation and taking. For additional
information on the military and ESA, see CRS Report RS22149, Exemptions from Environmental Law for the
Department of Defense (DOD), by David M. Bearden.
30 16 U.S.C. § 1533(f).
31 See http://ecos.fws.gov/tess_public/Boxscore.do for updated information.
32 16 U.S.C. § 1534.
33 16 U.S.C. § 1535.





appropriation.34 For FY2008, Congress appropriated $73.8 million for cooperative activities with
states and territories.
Federal agencies must ensure that their actions are “not likely to jeopardize the continued 35
existence” of any endangered or threatened species, nor to adversely modify critical habitat. If
federal actions or actions of non-federal parties that require a federal approval, permit, or funding 36
might affect a listed species, the federal action agencies must complete a biological assessment.
To be sure of the effects of their actions, the action agency must consult with the appropriate
Secretary. This is referred to as a § 7 consultation. “Action” includes any activity authorized,
funded, or carried out by a federal agency, including permits and licenses. However, a 2007
Supreme Court decision held that the consultation process is required only for those federal 37
actions that involve agency discretion. Where a federal action is dictated by statute, a § 7
consultation is not required.
If the appropriate Secretary finds that an action would neither jeopardize a species nor adversely
modify critical habitat, the Secretary issues a Biological Opinion (“BiOp”) to that effect, and the
agency is provided with a written incidental take statement (ITS), specifying the terms and
conditions under which the federal action may proceed in order to avoid jeopardy or adverse 38
modification of critical habitat. The Secretary must suggest any reasonable and prudent
alternatives that would be required to avoid harm to the species. The great majority of
consultations result in “no jeopardy” opinions, and nearly all of the rest find that the project has
reasonable and prudent alternatives which will permit it to go forward. Actions that would result
in jeopardy and have no reasonable and prudent alternatives are exceptionally rare. If no
reasonable and prudent alternatives to the proposed action can be devised to avoid the jeopardy or
adverse modification, the agency has three choices: (1) choose not to proceed with the action; (2)
proceed with the action at the risk of penalties, such as the risk of citizen suits under §11(g); or 39
(3) apply for a formal exemption for the action. Pending completion of the consultation process,
agencies may not make irretrievable commitments of resources that would foreclose any of these
alternatives.
A federal agency, an applicant or permittee, or the governor of a state in which the action in
question would occur may apply for an exemption that allows the action to go forward without 40
penalties. Exemptions are available only for actions (e.g., water withdrawals), not for species

34 16 U.S.C. §1535(i).
35 16 U.S.C. §1536(a).
36 16 U.S.C. §1536(c).
37 National Association of Home Builders v. Defenders of Wildlife, 127 S.Ct. 2518 (2007). (holding that no § 7
consultation was required to transfer permitting power to a state under a portion of the Clean Water Act (CWA)
because once the CWA statutory factors were met, EPA had no choice but to execute the transfer). See CRS Report
RS22618, The Supreme Court Decides Five Environmental Cases in Its 2006-2007 Term, by Robert Meltz.
38 16 U.S.C. § 1536(b)(4).
39 16 U.S.C. §1536(a).
40 16 U.S.C. §1536(g).





(e.g., Delta smelt). A high-level Endangered Species Committee of six specified federal officials
and a representative of each affected state (commonly called the “God Squad”) decides whether
to allow the action to proceed despite future harm to a species; at least five votes are required to
pass an exemption. The law includes extensive rules and deadlines to be followed in applying for
such an exemption and some stringent rules for the committee in deciding whether to grant an
exemption. The committee must grant an exemption if the Secretary of Defense determines that 41
an exemption is necessary for national security. In addition, and under specified circumstances,
the President may determine whether to exempt a project for the repair or replacement of
facilities in declared disaster areas. A separate discussion of the complex exemption process and 42
its history is provided in the Appendix.
ESA has provisions for emergencies; they apply when a species is in danger, not when a project
needs to be rushed. In § 4, which describes the process for listing species, ESA provides
shortened timelines for listing species where an emergency poses “a significant risk to the well-
being of any species.” The best scientific and commercial data must still be used. A shortened
period for obtaining an exemption or permit is also available, “where the health or life of an 43
endangered animal is threatened and no reasonable alternative is available to the applicant.”
For actions that might take a listed species, but without any federal nexus such as a loan or
permit, the Secretary may issue permits to allow “incidental take” of species for otherwise lawful 44
actions. The applicant for an incidental take permit (ITP) must submit a habitat conservation
plan (HCP) that shows the likely impact, the steps to minimize and mitigate the impact, the
funding for the mitigation, the alternatives that were considered and rejected, and any other
measures that the Secretary may require. Secretary Babbitt greatly expanded use of this section
during the Clinton Administration, and an agency handbook provides for streamlined procedures 45
for activities with minimal impacts.
Other provisions specify certain exemptions for raptors; regulate subsistence activities by Alaskan
Natives; prohibit interstate transport and sale of listed species and parts; control trade in parts or
products of an endangered species that were owned before the law went into effect; and specify

41 16 U.S.C. § 1536(e)-(p).
42 See also CRS Report 90-242 NR, Endangered Species Act: The Listing and Exemption Processes. A copy of this out-
of-print report can be obtained, on request, from M. Lynne Corn.
43 16 U.S.C. § 1539(c).
44 An incidental take occurs when listed species are harassed, harmed, pursued, hunted, shot, wounded, killed, trapped,
captured, or collected incidentally during activities done deliberately but for a lawful purpose other than the objective
of taking these listed species.
45 16 U.S.C. § 1539(a).





rules for establishing experimental populations.46 (Provisions of the ESA referring to international
activities are discussed below.)
The ESA prohibits certain actions, specifies criminal and civil penalties, and provides for citizens’ 47
suits to enforce certain aspects of the ESA. The citizen suit provisions have been a driving force
in the ESA’s history, and often have been used to force reluctant agencies to provide for species
conservation that might otherwise have been neglected.

The ESA implements the Convention on International Trade in Endangered Species of Wild 48
Fauna and Flora (CITES) and the Convention on Nature Protection and Wildlife Preservation in 49
the Western Hemisphere (the Western Hemisphere Convention) for the United States. CITES
parallels the ESA by dividing its listed species into groups according to the estimated risk of 50
extinction, but uses three major categories, rather than two. In contrast to the ESA, CITES
focuses exclusively on trade, and does not consider or attempt to control habitat loss. The
following are the major international provisions of the ESA.
The Secretary may use foreign currencies (available under 7 U.S.C. § 1691, the Food for Peace
program) to provide financial assistance to other countries for conserving endangered species.
(As a practical matter, little money is currently available under this provision.) The ESA also 51
authorizes appropriations for this purpose.
The ESA designates the Interior Secretary as the Endangered Species Scientific Authority (ESSA)
specified under CITES. As the ESSA, the Secretary must determine that the United States’
international trade of living or dead organisms, or their products, will not harm the species in
question. The Secretary has authority to enforce these determinations. The Secretary is required to

46 16 U.S.C. § 1539 (b)-(j).
47 16 U.S.C. §§ 1538 and 1540.
48 TIAS 8249, as signed by the United States, March 3, 1979. See CRS Report RL32751, The Convention on
International Trade in Endangered Species of Wild Fauna and Flora (CITES): Background and Issues, by Pervaze A.
Sheikh and M. Lynne Corn.
49 50 Stat. 1354; TS 981, as signed by the United States, October 12, 1940.
50 CITES Appendix I includes species threatened with extinction, and for which trade is permitted only in exceptional
circumstances. Appendix II includes species not necessarily threatened with extinction, but for which trade must be
controlled to avoid exploitation incompatible with their survival. Appendix III species are those protected in at least
one country that has asked other CITES Parties for assistance in controlling the trade.
51 16 U.S.C. §§ 1537 and 1542.





base export determinations upon “the best available biological information,” although population 52
estimates are not required. Certain other responsibilities are also spelled out in CITES.
The Interior Secretary is also named as the Management Authority for the United States under
CITES. The Management Authority must assure that specimens are exported legally, that
imported specimens left the country of origin legally, and that live specimens are shipped under 53
suitable conditions. Certain other responsibilities are also spelled out in CITES.
The ESA makes violations of CITES violations of U.S. law if committed within the jurisdiction 54
of the United States.
The ESA requires importers and exporters of controlled products to use certain ports and provides
for exemptions for scientific purposes and for programs intended to assist the recovery of listed 55
species. There are also certain exemptions for Alaska Natives and for products owned before 56
December 28, 1973, including scrimshaw (carved ivory).
The 1988 ESA amendments created the first of a series of programs that are not part of ESA but
do provide funds for species protected under the ESA. The first program was for the conservation
of African elephants. In 1994, Congress enacted a separate program for rhinoceros and tigers. In

1997, a program for Asian elephants was established. In 2000, a program for great apes was 57


added. In 2004, a program for marine turtles was added.

52 16 U.S.C. §§ 1537-1538.
53 16 U.S.C. § 1537.
54 16 U.S.C. § 1538.
55 16 U.S.C. 1538(f) and 1539(a). Subject to extra fees, importers or exporters may apply to use ports other than the 18
specifically designated by the Secretary (16 U.S.C. § 1537(f)). These extra fees may be considerable since qualified
FWS agents must be sent to oversee the shipment. Designated ports are Anchorage, Atlanta, Baltimore, Boston,
Chicago, Dallas, Honolulu, Houston, Los Angeles, Louisville (KY), Memphis, Miami, New Orleans, New York,
Newark, Portland (OR), San Francisco, Seattle. There have been pressures over the years to open other ports, but
budget constraints have generally limited such changes.
56 16 U.S.C. §§ 1538-1539.
57 Elephants: P.L. 100-478, Title II; 16 U.S.C. §§ 4201 et seq. Rhinoceros and tigers: P.L. 103-391; 16 U.S.C. §§ 5301
et seq. Asian elephants: P.L. 105-96; 16 U.S.C. §§ 4261 et seq. Great apes: P.L. 106-411; 16 U.S.C. §§ 6301 et seq.
Marine turtles: P.L. 108-266; 16 U.S.C. §§ 6601 et seq.






Because the listing of species, the designation of critical habitat, and the consultation and
exemption processes are such important and controversial aspects of the ESA, each of these
components is discussed in greater detail in this portion of the report.
As discussed above, the listing of a species under the ESA results in greater protection for the
species, limitations on activities that might affect that species, and penalties for “taking”
individuals of a listed species.
A species may be designated as either endangered or threatened, depending on the severity of its
decline and threats to its continued survival. Under § 3 of the ESA, an endangered species is a
species that is “in danger of extinction throughout all or a significant portion of its range.” A
threatened species is defined as a species “likely to become endangered within the foreseeable
future throughout all or a significant portion of its range.” Because the ESA defines species as a 58
species, a subspecies, or,—for vertebrates only—a “distinct population segment,” there is some
flexibility as to how to provide different levels of protection to less than a whole species.
In the last several years, the Department of the Interior (DOI) has interpreted the definition of
endangered species to find that only a species in danger of extinction throughout all of its range is
truly endangered. Under this interpretation, a species at risk of extinction only in a significant
portion of its range would not be considered endangered. Just about every court that considered 59
the issue found DOI’s interpretation violated the ESA, including one federal court of appeals. 60
And in 2007, DOI changed its interpretation. Under the new interpretation issued by the
Solicitor of DOI, FWS must also consider whether a species is at risk of extinction throughout a 61
significant portion of its range, allowing the agency discretion to define significant. The
interpretation also states that the range of a species is the area in which a species currently exists,
not the historical range where the species once existed.
The determination of whether a species should be listed as endangered or threatened must be 62
based on several scientific factors related to a species and threats to its continuance. The ESA

58 16 U.S.C. § 1532(16).
59 See, e.g., Defenders of Wildlife v. Norton, 258 F.3d 1136 (9th Cir. 2001); Nat’l Wildlife Fed. v. Norton, 386 F. Supp.
2d 553 (D. Vt. 2005); Defenders of Wildlife v. Norton, 354 F. Supp. 2d 1156 (D. Or. 2005); Defenders of Wildlife v.
Norton 239 F. Supp. 2d 9 (D.D.C. 2002). The only two exceptions have been Ctr. for Biological Diversity v. U.S. Fish
and Wildlife Service, No. 05-CV-00305-RPM (D. Colo. March 7, 2007); Ctr. for Biological Diversity v. Norton, 411 F.
Supp. 2d 1271 (D.N.M. 2005).
60 Memorandum from the Solicitor, DOI, to the Director, Fish and Wildlife Service,The Meaning ofIn Danger of
Extinction Throughout All or a Significant Portion of its Range (March 16, 2007).
61 Ibid. at 3.
62 16 U.S.C. § 1533(a)(1) states that the Secretary by regulation shall “determine whether any species is an endangered
species or a threatened species because of any of the following factors:
(A) the present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for
(continued...)





expressly states that listing determinations are to be made “solely on the basis of the best 63
scientific and commercial data available.” The word “solely” was added in the 1982 64
amendments to the ESA to clarify that the determination of endangered or threatened status was
intended to be made without reference to its potential economic impacts. Observers have
compared the decision of whether to list a species to diagnosing whether a patient has cancer: the
diagnosis should be a strictly scientific decision, but other factors can be considered later in
deciding how to treat the cancer. In discussing the addition of the word “solely,” a committee
report stated:
... The principal purpose of the amendments to Section 4 is to ensure that decisions
pertaining to the listing and delisting of species are based solely upon biological criteria and
to prevent non-biological considerations from affecting such decisions. To accomplish this
and other purposes, Section 4(a) is amended in several instances.
Section 4(b) of the Act is amended in several instances by Section 1(a)(2) of H.R. 6133.
First, the legislation requires that the Secretary base his determinations regarding the listing
or delisting of species solely on the basis of the best scientific and commercial data
available to him. The addition of the word “solely is intended to remove from the process of
the listing or delisting of species any factor not related to the biological status of the species.
The Committee strongly believes that economic considerations have no relevance to
determinations regarding the status of species and intends that the economic analysis
requirements of Executive Order 12291, and such statutes as the Regulatory Flexibility Act
and the Paperwork Reduction Act not apply. The committee notes, and specifically rejects,
the characterization of this language by the Department of the Interior as maintaining the
status quo and continuing to allow the Secretary to apply Executive Order 12291 and other
statutes in evaluating alternatives to listing. The only alternatives involved in the listing of
species are whether the species should be listed as endangered or threatened or not listed at
all. Applying economic criteria to the analysis of these alternatives and to any phase of the
species listing process is applying economics to the determinations made under Section 4 of
the Act and is specifically rejected by the inclusion of the word “solely in this legislation.
Section 4(b) of the Act, as amended, provides that listings shall be based solely on the basis
of the best “scientific and commercial data” available. The Committee did not change this
information standard because of its interpretation of the wordcommercial” to allow the use
of trade data. Retention of the wordcommercial” is not intended, in any way, to authorize 65
the use of economic considerations in the process of listing a species.
The conference report confirms that it was the intent of both chambers that economic factors not
play a role in the designation and listing of species for protection:

(...continued)
commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing
regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence.
63 In full, 16 U.S.C. § 1533(b)(1)(A) states: “The Secretary shall make determinations required by subsection (a)(1) of
this section solely on the basis of the best scientific and commercial data available to him after conducting a review of
the status of the species and after taking into account those efforts, if any, being made by any State or foreign nation, or
any political subdivision of a State or foreign nation, to protect such species, whether by predator control, protection of
habitat and food supply, or other conservation practices, within any area under its jurisdiction, or on the high seas.”
64 P.L. 97-304, 96 Stat. 1411.
65 H.Rept. 97-567, at 19-20.





Section 2 of the Conference substitute amends section 4 of the Act in several ways. The
principal purpose of these amendments is to ensure that decisions in every phase of the
process pertaining to the listing or delisting of species are based solely upon biological 66
criteria and to prevent non-biological considerations from affecting such decisions.
The Committee of Conference (hereinafter the Committee) adopted the House language
which requires the Secretary to base determinations regarding the listing or delisting of
species “solely on the basis of the best scientific and commercial date available to him. As
noted in the House Report, economic considerations have no relevance to determinations
regarding the status of species and the economic analysis requirements of Executive Order
12291, and such statutes as the Regulatory Flexibility Act and the Paperwork Reduction Act,
will not apply to any phase of the listing process. The standards in the Act relating to the
designation of critical habitat remain unchanged. The requirement that the Secretary consider
for listing those species that states or foreign nations have designated or identified as in need
of protection also remains unchanged.
The Committee adopted, with modifications, the Senate amendments which combined and
rewrote section 4(b) and (f) of the Act to streamline the listing process by reducing the time
periods for rulemaking, consolidating public meeting and hearing requirements and
establishing virtually identical procedures for the listing and delisting of species and for the 67
designation of critical habitat.
In summary, the ESA makes clear that whether a species is endangered or threatened is a
scientific question in which economic factors must not play a part. Once this determination is
made, economics then may be considered in analyzing and taking other actions such as
designating critical habitat or developing recovery plans. Nothing in the ESA prevents choosing
conservation methods that will lower costs to society, industry, or landowners, as long as the
chosen methods still achieve conservation goals.
The question may arise as to the responsibilities of the federal government toward a species that
is proposed for listing but has not yet been listed. This question could be important because there
may be a significant time between the proposal for listing and the actual listing, during which
time a federal agency could be faced with decisions on contracts and management actions of
various types. Under current law, an agency must “confer” with the appropriate Secretary on any
agency action that is likely to jeopardize the continued existence of any species proposed to be
listed or to destroy or adversely modify critical habitat proposed to be designated for such 68
species. The implementing regulations state that the conference is designed to assist the federal
agency and an applicant in identifying and resolving potential conflicts at an early stage in the 69
planning process.
The conference process that applies to species proposed for listing is distinct from the
consultation process that applies to listed species. The conference is intended to be less formal,
and to permit FWS or NMFS to advise an agency on ways to minimize or avoid adverse effects.

66 H.Rept. 97-835, at 19.
67 Ibid., at 20.
68 16 U.S.C. § 1536(a)(4).
69 50 C.F.R. § 402.10.





A federal agency has to follow more formal procedures and provide more complete
documentation once a species is listed. The agency may choose to follow the more complete and 70
formal process even at the proposed listing stage to avoid duplication of effort later.
The ESA states that the conference stage does not require a limitation on the irreversible or
irretrievable commitment of resources by agency action which would foreclose reasonable and 71
prudent alternative measures. Once a species is listed, an agency will have definite
responsibilities, and an agency might consider it prudent at the proposed listing stage both to
avoid harm to a precarious species and to avoid possible liability for compensation arising from
agency actions creating private rights that later cannot be exercised. For example, an agency
might choose to avoid holding timber sales in an area containing a proposed species. The relevant
Secretary must monitor candidate species and prevent a significant risk to the well-being of any
such species.
The Secretary may promulgate special regulations to address the conservation of species listed as 72
threatened. Protections and recovery measures for a particular threatened species can be
carefully tailored to particular situations, as was done, for example, with respect to the threatened
northern spotted owl. A federal regulation also clarifies that a threatened species for which a 73
special rule has not been promulgated enjoys the same protections as endangered species.
A distinct population segment (DPS) under ESA refers to a portion of a listed species, separated 74
from the rest of the species by genetic distinction and range. By definition, only vertebrates may 7576
be considered for DPSs. In 1996 a policy regarding DPS was introduced by FWS. The policy
contains the criteria that must be met for protection of a species at the population level. The
population must be discrete and significant. Discreteness is based on separation from other groups
of its kind. To be significant, the segment’s demise must be an important loss of genetic diversity.
Once the appropriate service finds a DPS exists, its protection status is determined using the same
criteria as for other listings. If the DPS is found to be threatened, special rules under § 4(d) of
ESA are written.

70 Ibid.
71 16 U.S.C. § 1536(a)(4).
72 16 U.S.C. 1533(d). This is §4(d) of the law and therefore such rules are often called “4 D rules.
73 50 C.F.R. § 17.31.
74 For more discussion on distinct population segments, see CRS Report RL34238, Gray Wolves Under the Endangered
Species Act (ESA): Distinct Population Segments and Experimental Populations, by Kristina Alexander and M. Lynne
Corn.
75 16 U.S.C. 1532(16).
76 61 Fed. Reg. 4722 (Feb. 7, 1996).





In 1982 Congress added the concept of experimental populations to the ESA as a way of
reintroducing species without risking severe restrictions on the use of private and public land in 77
the area. The practice allows reintroducing a species to its historic range.
Two criteria must be met. First, the service must have authorized the release of the population.
Second, the population must be wholly separate geographically from other animals of that
species. Congress required the separation so that the introduced population could be clearly
distinguished.
An experimental population’s protection status is determined differently from DPS or other
species. If the experimental population is in imminent danger of extinction it is deemed essential.
(Currently, there are no essential experimental populations.) Otherwise it is treated as
nonessential, and is considered threatened. Special regulations under Section 4 of ESA are made
regarding these populations, and can include rules for taking the species. Unless the experimental
population is in a national wildlife refuge or a national park, no Section 7 consultation is required
for an agency action that may take a member of the population. No critical habitat is designated
for non-essential experimental populations.
Critical habitat designation has been controversial, given FWS’s stated position (see below), the
importance that the environmental community attaches to critical habitat (especially in some
specific cases), and the distress its designation causes among many landowners.
Concurrently with determining a species to be endangered or threatened, the Secretary “to the 78
maximum extent prudent and determinable” is to designate the critical habitat of the species.
The reference to the designation of critical habitat being “prudent” reflects the need to consider
whether designating habitat would harm the species, for example, by identifying areas that could
be damaged by specimen collecting. If the facts relevant to the designation of critical habitat are
not yet “determinable,” the Secretary may postpone habitat designation for an additional year. 79
Eventually, habitat is to be designated to the maximum extent it is prudent to do so.
If the Secretary designates critical habitat, the Secretary must do so
on the basis of the best scientific data available and after taking into consideration the
economic impact, and any other relevant impact, of specifying any particular area as critical
habitat. The Secretary may exclude any area from critical habitat if he determines that the
benefits of such exclusion outweigh the benefits of specifying such area as part of the critical
habitat, unless he determines, based on the best scientific and commercial data available, that

77 P.L. 97-304 §6(6), 96 Stat. 1424; 16 U.S.C. § 1539(j). Experimental population designations are sometimes referred
to as Section 10(j) rules. For more discussion on experimental populations, see CRS Report RL34238, Gray Wolves
Under the Endangered Species Act (ESA): Distinct Population Segments and Experimental Populations, by Kristina
Alexander and M. Lynne Corn.
78 16 U.S.C. § 1533(a)(3).
79 16 U.S.C. § 1533(b)(6)(C).





the failure to designate such area as critical habitat will result in the extinction of the species 80
concerned.
Therefore, although economic factors are not to be considered in the listing of a species as
endangered or threatened, economic factors must be considered in the designation of critical
habitat, and some habitat areas may be excluded from designation based on such concerns, unless
the failure to designate habitat would result in the extinction of the species.
Although avoiding adverse modification of critical habitat is an express obligation only for
federal agencies and actions, it is frequently misunderstood by the public as the major restriction
on a private landowner’s authority to manage land. However, restrictions on use of private land
come primarily from the ESA’s prohibition on taking (as defined) of listed species. Only
occasionally—when some federal nexus is present—are they due to any additional strictures 81
resulting from designated critical habitat. Moreover, ESA provides significantly fewer 82
restrictions on the non-federal taking of listed plants than listed animals.
Both the Clinton and George W. Bush Administrations have supported restrictions on their own
ability to designate critical habitat under the ESA (e.g., proposed restrictions under the 83
appropriations process). In an announcement on October 22, 1999, FWS placed designation of
critical habitat at the lowest priority in its listing budget, and stated that it could not comply with
all of the demands of the ESA under current budget constraints. Conservation groups saw a
contradiction between that claim, and the agency’s repeated failure to request increased funds for
listing, together with requests that Congress place a special cap on funding for designation of 84
critical habitat.
FWS has designated critical habitat for 509 of the 1,351 listed domestic species. The agency has
been sued frequently for its failure to designate critical habitat and consistently loses such suits.
In the agency’s view, critical habitat offers little protection for a species beyond that already
available under the listing process, and thus the expense of designation, combined with its
perception of a small margin of additional conservation benefit, make critical habitat
requirements a poor use of scarce budgetary resources, especially if the public views critical
habitat as the major regulatory impact of the ESA, rather than as a supplement to the ESA’s 85
prohibition on “taking” a listed species.
According to FWS, critical habitat designation shows its greatest conservation benefit when it
includes areas not currently occupied by the species; these areas may be important as connecting
corridors between populations or as areas in which new populations may be re-introduced. FWS

80 16 U.S.C. § 1533(b)(2).
81 See CRS Report RS20263, Designation of Critical Habitat under the Endangered Species Act (ESA), by Pamela
Baldwin.
82 Compare 16 U.S.C. § 1538(a)(1) and (2).
83 For the current status on appropriations restrictions, see CRS Report RL33779, The Endangered Species Act (ESA) in
the 110th Congress: Conflicting Values and Difficult Choices, by Eugene H. Buck et al.
84 See, for example, Robert Wiygul and Heather Weiner, “Critical Habitat Destruction,Environmental Forum, vol. 16,
no. 6 (May/June 1999): 12-21.
85 On May 27, 1999, FWS Director Jamie Clark testified: “... under Section 7, Federal agencies already consult with the
Service on activities affecting listed species. In essence, these two processes [agency protection of listed species and of
designated critical habitat] often are identical, making critical habitat designation a redundant expenditure of
conservation resources.” Senate Committee on Environment and Public Works, S. Hrg. 106-437 on S. 1100.





proposed to “develop policy or guidance and/or revise regulations, if necessary, to clarify the role 86
of habitat in endangered species conservation.” The notice reflected the agency’s longstanding
disaffection for this provision of the law and its view that its conservation benefit is low
compared to its cost. However, while workshops were held on the topic, ultimately, no action was
taken on the proposal.
These agency assertions and conclusions rest on an agency regulation in 2000 that fails to 87
consider the role of critical habitat in the recovery of species, rather than its mere survival. In 88

2001, a federal court of appeals rejected that regulatory interpretation. In 2004, a second federal 89


court of appeals found the regulation contradicted the statute. If the agency interpretation is
changed to more closely reflect the statute, the role of critical habitat arguably would be more
meaningful in practice.
Under § 7 of the ESA,90 federal agencies are required to consult with the Secretary about
proposed actions that might affect a listed species; to use their authorities in furtherance of the
ESA; and to insure that any action authorized, funded, or carried out by the agency is not likely to
jeopardize the continued existence of any endangered or threatened species, or to destroy or
adversely modify critical habitat unless the agency has been granted an exemption under the 91
ESA. Consultation is usually begun at the request of the action agency, but may be initiated at 92
the request of an FWS Regional Director or NMFS’s Assistant Administrator for Fisheries.
Science plays an important role in the consultation process because the Secretary is to use the
“best scientific and commercial data available” to ascertain if a listed species might be present in 93
the area of a proposed agency action. If so, the action agency is to prepare a “biological
assessment” to explore whether a proposed action might jeopardize a listed species or its critical
habitat. This assessment also is to be based on “the best scientific and commercial data 94
available.” Consultation must also be initiated in connection with private lands if an applicant
for (or recipient of) federal funding, permit, or license has reason to believe that a listed species
may be present in the area affected by a project and implementation of the action will likely affect 95
the species.
The relevant Secretary generally is to complete consultation within 90 days for a wholly federal
action, unless the Secretary and the federal agency mutually agree to a longer period (up to 150

86 64 Federal Register 31871-31874 (June 14, 1999).
87 50 C.F.R. § 402.02.
88 Sierra Club v. U.S. Fish and Wildlife Service, 245 F.3d 434 (5th Cir. 2001).
89 Gifford Pinchot Task Force v. U.S. Fish and Wildlife Service, 378 F.3d 1059 (9th Cir. 2004).
90 16 U.S.C. § 1536.
91 Regulations on consultation are found at 50 C.F.R. Part 402.
92 50 C.F.R. § 402.14; and see the definition of Director in § 402.02.
93 16 U.S.C. § 1536(c). For additional information on the use of science in the ESA process, see CRS Report RS21500,
The Endangered Species Act (ESA), “Sound Science,and the Courts, by Pamela Baldwin, and CRS Report RL32992,
The Endangered Species Act and “Sound Science, by Eugene H. Buck et al.
94 16 U.S.C. § 1536(a)(2).
95 16 U.S.C. § 1536(a)(3).





days) and reasons are given for the delay.96 A consultation involving a non-federal party is to be
completed within the time agreed to by the Secretary, the federal agency involved, and the 97
applicant concerned.
Thereafter, FWS or NMFS will prepare a written statement, known as the biological opinion
(BiOp), analyzing whether the proposed agency action is likely to jeopardize the continued
existence of a listed species or to destroy or adversely modify critical habitat. The ESA does not
expressly state that the BiOp is to be based on the “best scientific and commercial data available,”
but this arguably is implied, and is expressly required under the implementing regulations, which
require that the consulting agency provide “the best scientific and commercial data available or 98
which can be obtained during the consultation.” Such information is to be the basis of the 99
BiOp, and the BiOp is to include a summary of the information on which the opinion is 100
based.
The BiOp may conclude that the agency action is not likely to jeopardize the species, or that the
action can be modified to avoid jeopardy. If so, FWS or NMFS may issue an incidental take
statement (ITS) that excuses the taking of listed species incidental to the otherwise lawful
activities that are to take place. If the BiOp concludes that the proposed action is likely to
jeopardize, FWS or NMFS must suggest reasonable and prudent alternatives to avoid jeopardy
and mitigate the impacts of the action. If this is not possible, then the agency proposing the action
must forego the action, risk incurring penalties under the ESA, or obtain a formal exemption from
the penalties of the ESA as set out below.
If the jeopardy that is expected to result from a proposed agency action cannot be avoided and the
agency proposing the action nonetheless wishes to go ahead with the action, the agency (or the
affected governor(s) or license applicant(s)) may apply for an exemption to allow the action to go
forward. The exemption process is an important way in which economic factors may be taken
into account under the ESA. Because the exemption process involves convening a cabinet-level
committee, there have only been six instances to date in which the exemption process was
initiated. Of these six, one was granted, one was partially granted, one was denied, and three were
dropped (see Appendix).
As originally enacted, the ESA contained an absolute prohibition against activities detrimental to
listed species. When the prospective impoundment of water behind the nearly completed Tellico
dam in Tennessee threatened to eradicate the only known population of the snail darter (a fish
related to perch), the Supreme Court concluded that the then-current “plain language” of the ESA
mandated that the gates of the dam not be closed:

96 16 U.S.C. § 1536(b)(1).
97 16 U.S.C. § 1536(b)(2).
98 50 C.F.R. § 402.14(d).
99 50 C.F.R. § 402.14(g)(8).
100 50 C.F.R. § 402.14(h).





Concededly, this view of the Act will produce results requiring the sacrifice of the
anticipated benefits of the project and of many millions of dollars in public funds. But
examination of the language, history, and structure of the legislation under review here
indicates beyond doubt that Congress intended endangered species to be afforded the highest 101
of priorities.
After this Supreme Court decision, the ESA was amended by P.L. 95-632 to include a process by
which economic impacts could be reviewed and projects exempted from the restrictions that
otherwise would apply. As originally enacted, the exemption process involved recommendations
by the Secretary of the Interior, processing by a review board, and then an application to the
Endangered Species Committee (ESC; commonly called the God squad). In 1982, P.L. 97-304
changed this process to eliminate the review board. The reviewing committee is composed of the
Secretary of Agriculture, the Secretary of the Army, the Chair of the Council of Economic
Advisors, the Administrator of the Environmental Protection Agency, the Secretary of the Interior
(who chairs the ESC), the Administrator of the National Oceanic and Atmospheric 102
Administration, and one individual from each affected state. By regulation, committee 103
members from affected states collectively have one vote.
A federal agency, the governor of a state in which an agency action will occur, or a permit or 104
license applicant may apply to the Secretary for an exemption for an agency action. How an
agency action is structured—whether, for example, it is a separate action or a region-wide
program—could be relevant to the various findings required under the exemption procedures. The
term “permit or license applicant” is defined in the ESA as a person whose application to a
federal agency for a permit or license has been denied primarily because of ESA prohibitions 105
applicable to the agency action. The regulations do not elaborate on who is included within this 106
term.
An exemption application from a federal agency must describe the consultation process carried
out between the head of the federal agency and the Secretary, and include a statement explaining
why the action cannot be altered or modified to conform with the requirements of the statute. All
applications must be submitted to the Secretary not later than 90 days after completion of the
consultation process, or within 90 days of final agency action if the application involves a federal
permit or license. An application must set out the reasons the applicant considers an exemption
warranted. The Secretary then publishes a notice of receipt of the application in the Federal
Register and notifies the governor of each affected state (as determined by the Secretary) so that
state members can be appointed to the ESC. The Secretary (acting alone) may deny the
application, if the preliminary steps have not been completed.
To be eligible for an exemption, the federal agency concerned and the exemption applicant must
have carried out the consultation processes required under § 7 of the ESA in good faith. The

101 Tennessee Valley Authority v. Hill, 437 U.S. 153, 174 (1978).
102 16 U.S.C. § 1536(e).
103 50 C.F.R. § 453.05(d).
104 16 U.S.C. § 1536(g).
105 16 U.S.C. § 1532(12).
106 50 C.F.R. § 450.01.





agency also must have made a reasonable and responsible effort to develop and fairly consider
modifications or reasonable and prudent alternatives to the proposed action that would not
jeopardize the continued existence of any endangered or threatened species or destroy or
adversely modify critical habitat of a species. In addition, the agency must have conducted
required biological assessments; and, to the extent determinable within the time provided,
refrained from making any irreversible or irretrievable commitment of resources that would
foreclose the formulation or implementation of reasonable and prudent alternatives that would 107
avoid jeopardizing the species and/or adversely modifying its habitat. These qualifying
requirements were put in place to insure that the exemption process is meaningful and that
consideration of the issues would not be preempted by actions already taken. Additional 108
requirements for an application are contained in the relevant regulations.
It is important to note that the exemption process begins only after a species is listed, consultation
has occurred, a finding has been made that the agency action is likely to jeopardize a species, and
it is determined that there are no reasonable and prudent alternatives to the agency action.
The Secretary is to determine whether an application is qualified within 20 days or a time
mutually agreeable to the applicant and the Secretary. Within 140 days of the time the Secretary
determines that the applicant is qualified, the Secretary, in consultation with the other members of
the ESC, must hold a formal hearing on the application and prepare a report. The purpose of the 109
formal hearing is to collect evidence both favoring and opposing the exemption. The
Secretary’s report reviews whether the applicant has made any irreversible or irretrievable
commitment of resources; discusses the availability of reasonable and prudent alternatives and the
benefits of each; provides a summary of the evidence concerning whether the action is in the
public interest and is nationally or regionally significant, and, if so, states why; and outlines
appropriate and reasonable mitigation and enhancement measures which should be considered by 110
the ESC.
Within 30 days after receiving the report of the Secretary, the ESC is to grant or deny an
exemption. The ESC shall grant an exemption for the project or activity if, based on the evidence,
the ESC determines that
(i) there are no reasonable and prudent alternatives to the agency action;
(ii) the benefits of such action clearly outweigh the benefits of alternative courses of action
consistent with conserving the species or its critical habitat, and such action is in the public
interest;
(iii) the action is of regional or national significance; and

107 16 U.S.C. § 1536(g).
108 50 C.F.R. § 450 et seq.
109 H.Rept. 97-835, at 28.
110 16 U.S.C. § 1536(g)(5).





(iv) neither the federal agency concerned nor the exemption applicant made any irreversible
or irretrievable commitment of resources prohibited by subsection (d) of this section 111
[commitments as described above that jeopardize species or critical habitat].
If the ESC grants an exemption, it also must establish reasonable mitigation and enhancement
measures that are “necessary and appropriate to minimize the adverse effects” of an approved 112
action on the species or critical habitat. The exemption applicant (whether federal agency,
governor, or permit or license applicant) is responsible for carrying out and paying for 113
mitigation.
The costs of mitigation and enhancement measures specified in an approved exemption must be
included in the overall costs of continuing the proposed action, and the successful applicant must
report annually to the Council on Environmental Quality on compliance with mitigation and 114
enhancement measures.
The ESA specifies certain particular instances when special provisions will apply.
The ESC cannot grant an exemption for an agency action if the Secretary of State, after a hearing
and a review of the proposed agency action, certifies in writing that carrying out the action for
which an exemption was sought would violate a treaty or other international obligation of the 115
United States. This provision could enter in if a particular species listed under the ESA were
also protected under treaties, such as the Migratory Bird Treaties to which the United States is a
party. The Secretary of State is to make this determination within 60 days “of any application
made under this section,” a time limit which may be unrealistic given the longer length of time
the Secretary of the Interior has to prepare the report that will fully describe the agency action to
be reviewed by the Secretary of State.
The committee is required to grant an exemption if the Secretary of Defense finds that an 116
exemption is necessary for reasons of national security. We know of no instance on the public
record in which this provision has been used.

111 16 U.S.C. § 1536(h)(1)(A).
112 16 U.S.C. § 1536(h)(1)(B).
113 16 U.S.C. § 1536(l)(1).
114 16 U.S.C. § 1536(l)(2).
115 16 U.S.C. § 1536(i).
116 16 U.S.C. § 1536(j).





The President may grant exemptions in certain cases involving facilities in presidentially declared
disaster areas. This provision appears to be written in contemplation of domestic disasters, such 117
as hurricanes. The ESA does not have a general provision that allows the granting of an 118
exemption in other emergency conditions.
An exemption is permanent unless the Secretary finds that the exemption would result in the
extinction of a species that was not the subject of consultation or was not identified in a biological 119
assessment and the ESC determines that the exemption should not be permanent.
The ESA expressly states that the penalties that normally apply to the taking of an endangered or 120
threatened species do not apply to takings resulting from actions that are exempted.

117 16 U.S.C. § 1536(p).
118 50 C.F.R. § 13.4 states that in emergency conditions, the FWS Director “may approve variations from the
requirements of this part [the general permit procedures] when he finds that any emergency exists and that the proposed
variations will not hinder effective administration of [the subchapter on permits], and will not be unlawful.” It is not
clear the extent to which this regulation may provide relief for an agency action that otherwise would likely need an
exemption.
119 16 U.S.C. § 1536(h). This provision allows for repair or replacement of public facilities (e.g., levees). Disasters such
as droughts declared by the Secretary of Agriculture rather than the President are not included in this provision.
120 16 U.S.C. § 1536(o).






In three instances, an Endangered Species Committee (ESC) reached a decision on an application
for an exemption:
Grayrocks Dam. The Platte River is a major stopover site on the migration path of whooping
cranes, listed under the ESA as an endangered species. FWS determined that the construction of
the Grayrocks Dam and Reservoir in Wyoming, along with existing projects in the Platte River
Basin, would jeopardize the downstream habitat of whooping cranes. The ESC voted (7-0) to
grant an exemption for Grayrocks Dam and Reservoir on January 23, 1979, conditioned on
specified mitigation measures that included maintenance and enhancement of critical whooping
crane habitat on the Platte River, as well as a permanent, irrevocable trust fund to pay for these
activities. A previous enactment by Congress would have exempted the project, if the ESC had 121
not reached a decision within a certain time.
Tellico Dam. The Tellico Dam on the Little Tennessee River was to serve multiple purposes. It
was vigorously opposed by several sectors, including local landowners and Indian tribes. After
the snail darter (a fish) was listed as endangered, litigation was filed to stop the construction of
the dam, resulting in the landmark Supreme Court case TVA v. Hill. The decision clarified the
broad reach of the ESA, and its relationship to the question of ratification of public works
projects through appropriations measures. The decision was quickly followed by congressional
passage of P.L. 95-632, which provided for an ESC process. The measure also gave an automatic
exemption to the dam if the ESC did not reach a decision within a specified time. Directed to take
economic implications into account, the ESC denied an exemption for Tellico (on a 7-0 vote), but
Congress enacted an exemption in P.L. 96-69, and the dam was completed. Subsequently,
additional snail darters were found in a few other locations, and the snail darter was reclassified
as threatened.
Bureau of Land Management Timber Sales. The Bureau of Land Management, an agency in
DOI, sought an exemption for 44 Oregon timber sales in the habitat of the threatened northern
spotted owl. In 1992, the ESC voted (5-2) to grant an exemption for 13 of the sales. Controversy
over the sales and the processes within the Department continued, and the 13 timber sales were
subsequently withdrawn in the Clinton Administration.
In three other instances, there were applications for exemptions, but no ESC decisions:
Pittston Company Refinery. The Pittston Company applied for an exemption to build a refinery
in Eastport, Maine. Following jeopardy opinions based on probable effects on threatened bald
eagles and endangered right and humpback whales, the company applied for an exemption, but
further action on this application appears to have been discontinued in 1982.
Consolidated Grain and Barge Company Docking Area. This company sought to build a
docking area for barges at Mound City, Illinois, on the Ohio River, an area that was habitat for an
endangered mussel. Following a jeopardy opinion, and a denial of permits by the Army Corps of
Engineers, the company applied for an exemption, but withdrew the application in 1986.

121 P.L. 95-632.





Suwanee River Authority. The consulting engineer of the Suwanee River Authority applied for
an exemption for a project to dredge Alligator Pass in Suwanee Sound, Florida, part of the habitat
for the endangered manatee. The project had been denied a permit by the Army Corps of
Engineers. The engineer apparently lacked the authority to apply on behalf of the Authority,
which in 1986 refused to ratify his actions and withdrew the application. Although the engineer
attempted to continue the application, the withdrawal was effective.
M. Lynne Corn Kristina Alexander
Specialist in Natural Resources Policy Legislative Attorney
lcorn@crs.loc.gov, 7-7267 kalexander@crs.loc.gov, 7-8597
Eugene H. Buck
Specialist in Natural Resources Policy
gbuck@crs.loc.gov, 7-7262