Critical Infrastructures: What Makes an Infrastructure Critical?

Critical Infrastructures: What Makes an Infrastructure Critical?

Order Code RL31556
Report for Congress
Received through the CRS Web
Critical Infrastructures:
What Makes an
Infrastructure Critical?
Updated January 29, 2003
John Moteff, Claudia Copeland, and John Fischer
Resources, Science, and Industry Division
Congressional Research Service ˜ The Library of Congress

Critical Infrastructures:
What Makes an Infrastructure Critical?
Summary
The Bush Administration’s proposal for establishing a Department of Homeland
Security includes a function whose responsibilities include the coordination of
policies and actions to protect the nation’s critical infrastructure. However, the
proposal did not specify criteria for how to determine criticality or which
infrastructures should be considered critical.
Over the last few years, a number of documents concerned with critical
infrastructure protection have offered general definitions for critical infrastructures
and have provided short lists of which infrastructures should be included. None of
these lists or definitions would be considered definitive. The criteria for determining
what might be a critical infrastructure, and which infrastructures thus qualify, have
expanded over time. Critical infrastructures were originally considered to be those
whose prolonged disruptions could cause significant military and economic
dislocation. Critical infrastructures now include national monuments (e.g.
Washington Monument), where an attack might cause a large loss of life or adversely
affect the nation’s morale. They also include the chemical industry. While there may
be some debate about why the chemical industry was not on earlier lists that
considered only military and economic security, it seems to be included now
primarily because individual chemical plants could be sources of materials that could
be used for a weapon of mass destruction, or whose operations could be disrupted in
a way that would significantly threaten the safety of surrounding communities.
A fluid definition of what constitutes a critical infrastructure could complicate
policymaking and actions. At the very least, a growing list of infrastructures in need
of protection will require the federal government to prioritize its efforts. Essentially
the federal government will have to try to minimize the impact on the nation’s critical
infrastructure of any future terrorist attack, taking into account what those impacts
might be and the likelihood of their occurring.
There are number of ways the government can prioritize. First, not all elements
of a critical infrastructure are critical. Additional study will be necessary to identify
those elements that are the most critical. Other approaches include focusing on
vulnerabilities that cut across more than one infrastructure, interdependencies where
the attack on one infrastructure can have adverse effects on others, geographic
locations where a number of critical infrastructure assets may be located, or focusing
on those infrastructure belonging solely to the federal government or on which the
federal government depends.
The National Strategy for Homeland Security, released by the Bush
Administration in July 2002, states that the federal government will set priorities for
critical infrastructure protection based on a consistent methodology and an approach
that will allow it to balance the cost and expected benefits. It does not discuss what
that methodology or approach might be. Congress may want to focus some of its
oversight on how the Administration proposes to set priorities and what criteria it
uses to do so. This report will be updated as warranted.

Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
What Is a Critical Infrastructure? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Which Assets of a Critical Infrastructure Need Protection? . . . . . . . . . . . . . 8
Surface Transportation: River Crossings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Transportation Systems: Air Traffic Control (ATC) . . . . . . . . . . . . . . . . . . 10
Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
What is Infrastructure? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
How the Criteria and Components of Critical Infrastructure Have
Expanded Over Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
List of Tables
Table 1. What Constitutes Critical Infrastructure Over Time . . . . . . . . . . . . . . . 17

Critical Infrastructures: What Makes an
Infrastructure Critical?
Introduction
Section II of President Bush’s June 2002 proposal for establishing a Department
of Homeland Security prescribed the responsibilities of the Department’s
Undersecretary for Information Analysis and Infrastructure Protection. Those
responsibilities included:
! comprehensively assessing the vulnerabilities of the key resources
and critical infrastructures in the United States;
! ....identifying protective priorities and supporting protective
measures...;
! developing a comprehensive national plan for securing the key
resources and critical infrastructures in the United States; and
! taking or seeking to effect necessary measures to protect the key
resources and critical infrastructures in the United States....1
Nowhere in the Administration’s proposed legislation was critical infrastructure
defined. However, other documents, including previous legislation, have defined
critical infrastructure and provided illustrative lists of infrastructures that fall within
those definitions. The following discussion recounts how the definition (and the list
of illustrative examples) has broadened over time and what impact this may have on
developing and implementing critical infrastructure protection policy.
Background
What Is a Critical Infrastructure?
Before “critical infrastructure” became a term of interest in the terrorism and
homeland security debate, the seemingly similar term “infrastructure” was a subject
debated by public policymakers. In the 1980s, for example, a much debated issue
was whether there was a national crisis in the condition of America’s
infrastructure–its roads, bridges, dams, wastewater treatment systems, etc. With no
standard or agreed definition, the concept of infrastructure in policy terms has been
fluid, as it appears to be today. (For more discussion of these earlier definitions of
1 For more information on various aspects of the President’s proposal and the Congressional
response, see Homeland Security on the CRS Home Page [http://www.crs.gov/] .

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and debate regarding “infrastructure,” see the Appendix, What is Infrastructure? In
this report.)
More recently, as homeland security as been assigned the highest national
priority, the term “critical infrastructure” has developed into a major policy concern.
Documents dealing with critical infrastructure protection have provided broad
definitions of what makes an infrastructure critical.
Executive Order 13010,2 signed by President Clinton on July 15, 1996, which
established the President’s Commission on Critical Infrastructure Protection, alluded
to what makes an infrastructure critical:
“Certain national infrastructures are so vital that their incapacity or
destruction would have a debilitating impact on the defense or economic
security of the United States.”3
According to this Executive Order (EO) these infrastructures included:
! telecommunications;4
! electrical power systems;
! gas and oil storage and transportation;
! banking and finance;
! transportation;
! water supply systems;
! emergency services (including medical, police, fire, and rescue);
and,
! continuity of government.
Using the language of this EO, the Commission’s final report5 to the President
defined critical infrastructure in the Glossary as:
“Infrastructures so vital that their incapacitation or destruction would have
a debilitating impact on defense or economic security.”
The following supporting definitions were provided:
Infrastructures: The framework of interdependent networks and systems
comprising identifiable industries, institutions (including people and
procedures), and distribution capabilities that provide a reliable flow of
products and services essential to the defense and economic security of the
2 Executive Order 13010—Critical Infrastructure Protection. Federal Register, July 17,
1996. Vol. 61, No. 138. pp 37347-37350. Reference is on page 37347.
3 Ibid. p. 37347.
4 Throughout this report, sectors that are identified as being critical will be bolded the first
time they appear.
5 President’s Commission on Critical Infrastructure Protection, Critical Foundations:
Protecting America’s Infrastructure, October 1997.

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United States, the smooth functioning of government at all levels, and
society as a whole.
Debilitated: A condition of defense or economic security characterized by
ineffectualness.
Defense security: The confidence that Americans’ lives and personal
safety, both at home and abroad, are protected and the United States’
sovereignty, political freedom, and independence, with its values,
institutions, and territory intact are maintained.
Economic security: The confidence that the nation’s goods and services
can successfully compete in global markets while maintaining or boosting
real incomes of its citizens.
The Commission’s report also defined the infrastructures of each of the sectors
mentioned in this EO.
Banking and Finance: Entities such as retail and commercial
organizations, investment institutions, exchange boards, trading houses,
and reserve systems, and associated operational organizations, government
operations, and support activities that are involved in all manner of
monetary transactions, including its storage for saving purposes, its
investment for income purposes, its exchange for payment purposes, and
its disbursement in the form of loans and other financial instruments.
Electric Power Systems: Generation stations, transmission and distribution
networks that create and supply electricity to end-users so that end-users
achieve and maintain nominal functionality, including the transportation
and storage of fuel essential to that system.
Emergency Services: Medical, police, fire, and rescue systems and
personnel that are called upon when an individual or community is
responding to emergencies. These services are typically provided at the
local level. In addition, state and federal response plans define emergency
support functions to assist in the response and recovery.
Gas and Oil Production Storage and Transportation: The production and
holding facilities for natural gas, crude and refined petroleum, and
petroleum-derived fuels, the refining and processing facilities for these
fuels and the pipelines, ships, trucks, and rail systems that transport these
commodities from their source to systems that are dependent upon gas and
oil in one of their useful forms.
Information and Communications: Computing and telecommunications
equipment, software, processes, and people that support:
! the processing, storage, and transmission of data and information;
! the processes and people that convert data into information and
information into knowledge; and,

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! the data and information themselves.
Transportation: Physical distribution systems critical to supporting the
national security and economic well-being of this nation, including the
national airspace systems, airlines, and aircraft, and airports; roads and
highways, trucking and personal vehicles; ports and waterways and the
vessels operating thereon; mass transit, both rail and bus; pipelines,
including natural gas, petroleum, and other hazardous materials; freight
and long haul passenger rail; and delivery services.
Water Supply System: Sources of water, reservoirs, and holding facilities,
aqueducts and other transport systems, the filtration, cleaning and
treatment systems, the pipelines, the cooling systems and other delivery
mechanisms that provide for domestic and industrial applications,
including systems for dealing with water runoff, waste water, and
firefighting.
In response to the Commission’s report, President Clinton signed Presidential
Decision Directive Number 63 (PDD-63) on May 22, 1998.6 The Directive defined
critical infrastructures as “those physical and cyber-based systems essential to the
minimum operations of the economy and government.”7 According to the Directive,
these included, but were not limited to, telecommunications, energy, banking and
finance, transportation, water systems and emergency services.
The Directive also directed certain agencies to identify sector liaisons in those
sectors mentioned above, plus:
! intelligent transportation systems;
! continuity of government services;
! public health services (including prevention, surveillance, laboratory
services); and,
6 The Clinton Administration’s Policy on Critical Infrastructure Protection: Presidential
Decision Directive No. 63, White Paper, May 22, 1998.
7 The distinction between physical-security and cyber-security is almost inextricable and not
clearly articulated. For example, physical assets in the electric power infrastructure would
typically include the generation plant, the turbines and other equipment inside, and
distribution lines and towers. However, the computer hardware and communication lines
that help control the generation and flow of electricity could be considered physical assets
or cyber assets. The data transmitted and stored on the computers and transmitted over the
communication lines and the software used to process and control that data are typically
considered cyber assets. Physical security typically means protecting the physical assets
(including computer equipment) from damage caused by physical forces such as explosion,
breakage, wind, fire, etc. Cyber-security could also mean the physical protection of cyber
assets. Cyber-security, however, typically includes the protection of both physical and cyber
assets from operational failure or from being otherwise compromised by others gaining
unauthorized computer access (including remote access) to the operating software or data.
Providing physical- and cyber-security of critical infrastructures requires a broad range of
effort that can be quite varied (from installing jersey walls to installing firewall software),
and different people or policies may be talking about different activities.

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! personal health services.
It also identified critical infrastructures that are primarily the responsibility of
the federal government:
! law enforcement and internal security;
! foreign intelligence;
! foreign affairs; and,
! national defense.
The Directive also set a goal that within five years the nation should be able to
protect the national critical infrastructures from intentional attacks that would
significantly diminish the abilities of:
! the federal government to perform essential national security
missions and to ensure the general public health and safety;
! state and local governments to maintain order and to deliver
minimum essential public services; and,
! the private sector to ensure the orderly functioning of the economy
and the delivery of essential telecommunications, energy, financial,
and transportation services.
“Any disruptions or manipulations of these critical functions must be brief,
infrequent, manageable, geographically isolated and minimally detrimental to the
welfare of the United States.”8
The first version of a National Plan for Critical Infrastructure (also called for by
PDD-63)9 defined critical infrastructures as “those systems and assets—both physical
and cyber—so vital to the Nation that their incapacity or destruction would have a
debilitating impact on national security, national economic security, and/or national
public health and safety.”10 While the Plan concentrated on cyber-security of the
federal government’s critical infrastructure, the Plan refers to those infrastructures
mentioned in the Directive.
Following the September 11, 2001 attacks, President Bush signed new
Executive Orders relating to critical infrastructure protection. E.O. 13228,11 signed
October 8, 2001, established the Office of Homeland Security and the Homeland
Security Council. Among the duties assigned the Office was to:
8 Ibid. p2.
9 Defending America’s Cyberspace: National Plan for Information Systems Protection.
Version 1.0. An Invitation to a Dialogue. White House. 2000
10 Ibid. Executive Summary. p 1. Section 1016 of the USA Patriot Act (P.L.107-56), passed
October 16, 2001, used essentially the same definition.
11 Executive Order 13228—Establishing the Office of Homeland Security and the Homeland
Security Council. Federal Register, Vol. 66, No. 196, October 8, 2001. pp51812- 51817.

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“coordinate efforts to protect critical infrastructures..[and]...work with
federal, state, and local agencies and private entities to:
strengthen measures for protecting energy production, transmission, and
distribution services and critical facilities; other utilities;
telecommunications; facilities that produce, use, store, or dispose of
nuclear material...;
...coordinate efforts to protect critical public and privately owned
information systems...;
...to ensure that special events determined by appropriate senior officials
to have national significance are protected...;
...to protect transportation systems within the United States, including
railways, highways, shipping ports and waterways, and airports and
civilian aircraft...;
...to protect United States livestock, agriculture, and systems for the
provision of water and food for human use and consumption....”12
In a separate Executive Order 13231,13 signed October 16, 2001, President Bush
established the President’s Critical Infrastructure Protection Board. Although the
name of the Board might imply a broad mandate, the Board’s duties focus primarily
on the nation’s information infrastructure. However, the EO makes reference to the
importance of information systems to other critical infrastructures such as
“telecommunications, energy, financial services, manufacturing, water,
transportation, health care, and emergency services.”14
This EO also reiterates the goal established in PDD-63, although stated within
the more limited context of protecting against attacks on the nation’s information
infrastructure, that “any disruptions that occur are infrequent, of minimal duration,
and manageable, and cause the least damage possible.”15
Shortly after the Administration issued these Executive Orders, Congress passed
the USA PATRIOT Act (P.L. 107-56). Section 1016 of the Act, called the Critical
Infrastructures Protection Act of 2001, defined critical infrastructures as:
“...systems and assets, whether physical or virtual, so vital to the United
States that the incapacity or destruction of such systems and assets would
12 Ibid. Section 3 (e) (i), (ii), (iv), (v) and (vi), pp. 5183-5184.
13 Executive Order 13231—Critical Infrastructure Protection in the Information Age.
Federal Register, Vol. 86, No. 202. October 18, 2001. pp. 53063-53071.
14 Ibid. Section 1 (a), p. 53063.
15 Ibid. Section 1 (b), p. 53063

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have a debilitating impact on security, national economic security, national
public health and safety, or any combination of those matters.”16
Earlier in Section 1016, the legislation mentioned the types of infrastructures
Congress intended to include in this definition: information, telecommunications,
energy, financial services, water, and transportation.
Although the draft legislation proposed by the President for establishing the
Department of Homeland Security did not define critical infrastructure, a companion
document17 went into a little more detail. While not providing a formal definition,
the text parenthetically described critical infrastructures as “those assets, systems, and
functions vital to our national security, governance, public health and safety,
economy, and national morale.”18
The text also states that the Department would build and maintain a
comprehensive assessment of our nation’s infrastructure sectors:
! food;
! water;
! agriculture;
! health systems and emergency services;
! energy (electrical, nuclear, gas and oil, dams);
! transportation (air, road, rail, port, waterways);
! information and telecommunications;
! banking and finance;
! energy;
! chemical;
! defense industry;
! postal and shipping; and,
! national monuments and icons.19
On July 16, 2002 the Administration released its National Strategy on Homeland
Security.20 Early in the Strategy, critical infrastructure was defined as it was in the
above document (i.e. including the mention of national morale).21 In the separate
section focusing on critical infrastructure, the Strategy referred to the definition in the
USA PATRIOT Act.22 The National Strategy mentioned a slightly different list of
specific infrastructures, making a distinction between public health systems and
16 H.R. 3162-130 (P.L. 107-56), Section 1016(e). The two bills before Congress establishing
a Department of Homeland Security (H.R. 5005 and S. 2452) both use this definition.
17 The Department of Homeland Security. June 2002. White House.
18 Ibid. p15.
19 Ibid. p15.
20 Office of the President. Office of Homeland Security. National Strategy for Homeland
Security. July 2002.
21 Ibid. p.ix
22 Ibid. p. 30.

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emergency systems and dropping national monuments and icons. The latter were
picked up in a distinction the Strategy makes between critical infrastructures and key
assets. Key assets were defined as individual targets whose “destruction would not
endanger vital systems, but could create local disaster or profoundly damage our
nation’s morale and confidence.” Such assets would include historical attractions
(national, state, and local monuments and icons) and other localized facilities with
destructive potential or of high value to a community such as schools, courthouses,
and bridges. While these key assets may be more the responsibility of the state and
locality to protect, the Strategy offered a federal commitment to help enable those
authorities to protect their key assets.
Which Assets of a Critical Infrastructure Need Protection?
After identifying what may be considered a critical infrastructure, a protection
strategy must identify which elements of the infrastructure are critical to its function
or pose the most significant danger to life and property. Not all assets may be critical,
and some may be more so than others. However, the size and complexity of these
infrastructures can make identifying which assets of an infrastructure are critical a
daunting task.
For example, a recent report by the National Research Council (NRC)
characterizes the extent of the U.S. domestic transportation system as follows:

The U.S. highway system consists of 4 million interconnected miles of paved
roadways, including 45,000 miles of interstate freeway and 600,000
bridges. The Freight rail networks extend for more than 300,000 miles and
commuter and urban rail system’s cover some 10,000 miles. Even the more
contained civil aviation system has some 500 commercial-service airports
and another 14,000 smaller general aviation airports scattered across the
country. These networks also contain many other fixed facilities such as
terminals, navigation aids, switch yards, locks, maintenance bases and
operation control centers.23
Left out of this description of the transportation system is a large maritime
infrastructure of inland waterways, ports, and vessels.
Similarly, the electric power infrastructure includes 92,000 electric generating
units (including fossil fueled, nuclear, and hydroelectric units), 300,000 miles of
transmission lines, and 150 control centers, regulating the flow of electricity. The
nation’s water infrastructure includes 75,000 dams and reservoirs, thousands of miles
of pipes and aqueducts, 168,000 public drinking water facilities, and 16,000
publically owned waste water treatment facilities. The chemical industry includes
thousands of chemical facilities that handle hazardous or toxic substances.24
23 National Research Council. Transportation Research Board. TRB Special Report 270.
Deterrence, Protection, and Preparation--The New Transportation Security Imperative.
July 2, 2002. Available in preprint form at [http://www.trb.org/]
24 For more information on these infrastructures, see CRS Terrorism Briefing Book,
(continued...)

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Fortunately, a considerable amount of information that can be used to categorize
infrastructure is already available at the federal level. For example, the Federal
Highway Administration classifies highways by type and produces copious statistics
about them. Some of this information could be quite useful in a discussion about
which parts of the transportation infrastructure are most critical. The National
Highway System, which is a category of roads that includes the interstate highway
system, constitutes only 4% of the nation’s public road milage, but carries over 44%
of all travel.25 A similar situation exists in the aviation system. Of the 546
commercial airports that had airline service in April 2001, fully 70% of all airline
passenger boardings occurred at just 31 airports.26
What follows are two brief discussions that consider how physical
transportation assets and transportation systems might be thought of in the context
of whether they are, or are not, critical. The discussion is relevant to the other
infrastructures as well.
Surface Transportation: River Crossings
There are 10 bridge spans crossing the Potomac River within the Washington
D.C. Beltway. The two Beltway bridges, Woodrow Wilson and American Legion,
are both part of the interstate highway system as are the 14th Street Bridge (which
has multiple spans) and the Theodore Roosevelt Bridge. Other highway bridges
include Memorial Bridge, Key Bridge, and Chain Bridge. Less noticed, but also
important components of the area’s transportation infrastructure are the rail and
Metrorail bridges that parallel the 14th Street Bridge. One additional crossing of the
Potomac exists, the Metrorail tunnel between Foggy Bottom and Rosslyn stations.
In the context of homeland security, which of these crossings are critical? At
first blush, most observers would probably identify the Woodrow Wilson Bridge as
the area’s most critical transportation structure. It is the busiest, and carries Interstate
95, the East Coast’s busiest highway around Washington. But if the Wilson Bridge
were lost to a terrorist attack for some period of time how badly would the local
economy and interstate commerce suffer? The answer based on experience with
major traffic accidents and other emergencies is that the short term situation would
likely be chaotic. Over the longer term, traffic would adjust in some ways. Interstate
commerce, for example, would go around the Beltway the other way or through the
City. These routes are longer and increased congestion would make these routings
costlier and less efficient. All of these additional costs would be added to the cost
of travel in the region which affect a host of activities. Nonetheless, the loss of the
use of a single bridge or more could likely be handled, albeit with difficulty.
24 (...continued)
Prevention: Security Enhancements. [http://www.congress.gov/brbk/html/ebter1.shtml]
2 5 Federal Highway Administration. Our Nations Highways: 2000.
[http://www.fhwa.dot.gov/ohim]. p.18.
26 Transportation Research Board. Aviation Gridlock: Phase II: Airport Capacity and
Infrastructure. Transportation Research E-Circular.
[http://trb.org/trb/publications/circulars/ec032/ec032.pdf]. May 2001. p. 5.

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A more difficult question arises if the bridge that is lost is either the Metrorail
bridge or the rail bridge. The tunnel crossing does provide a backup of sorts for the
Metrorail system, but by all public accounts the rail lines that run through the tunnels
are already nearing capacity, at least at certain times of the day. The rail crossing
handles most of Amtrak’s east coast service, Virginia Rail Express, and a significant
amount of freight traffic. The nearest north-south replacement for the 14th St. rail
crossing is over 40 miles to the west. This is obviously not a suitable replacement
for rail passenger service destined for Washington. For freight this might be
something less of an issue, but the loss of this rail corridor for any period of time
would affect the shipment of a lot of commodities, only some of which could be
carried by truck as an alternative. Thus, determination of what is “critical” depends
a great deal on ones frame of reference.
Transportation Systems: Air Traffic Control (ATC)27
The air traffic control system is a different type of example of the problem of
defining critical transportation infrastructure. The ATC system is a large, complex,
and highly integrated system that is very reliant on technology. The ATC system has
40,921 operational facilities of all types, staffed by 36,349 employees. Most notable
of the facilities from the public perspective are the 21 air route traffic control centers
(ARTCC), 496 airport traffic control towers, 75 flight service stations, and 61
automated flight service stations. The ARTCC alone handled almost 7 million
aircraft movements during just the months of January and February 2002. For safety
reasons a great deal of redundancy is already built into the system.
In structure a highly integrated system like ATC probably has more in common
with telecommunications critical infrastructure then with traditional transportation
infrastructure. In purpose, however, it is much more of a command and control
system for the nation’s air system. Aircraft can certainly fly without ATC guidance,
and many aircraft flying by visual flight rules (VFR) already do. But the airline
system could not function in its present manner without ATC.
The ATC system is strategic and is closely linked with the military ATC system.
Considerable cooperation exists between the Department of Defense (DOD) and the
ATC. Considerable thought has also been given to how the ATC system would
operate in time of war. Many of the plans developed in this process also have
application for dealing with terrorism.
The question, however, can be raised about which specific ATC facilities are
critical. The system, for example, can, and does, function with the loss of an
ARTCC. Coverage, however, is greatly reduced in the affected area and air traffic
usually slows dramatically. A long term loss of such a facility would probably
engender even further disruption and could lead to major disruptions of commerce
in the affected region. The loss of a radar or other flight tracking facility at a major
27 Information about the ATC in this section is from the Federal Aviation Administration.
Administrator’s Fact Book. May 2002. available at
[http://www.ama500.jccbi.gov/factbook/]

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airport, however, at a particular moment could, depending on the circumstances, be
either inconsequential or catastrophic.
Observations
The most apparent strength of the U.S. transportation system in the face of a
terrorist threat is its redundancy. Although the transportation system is frequently
congested in urbanized areas there are usually alternative transportation routes or
facilities that come into play. There are a few instances where this is not the case and
these are probably the real “critical” pieces of transportation infrastructure. The same
is true in the other infrastructures.
Analysis
None of the definitions of what constitutes a critical infrastructure, given over
the years, could be considered rigorous. They bound the issue somewhat, but leave
plenty of room for interpreting which infrastructures fit the definition. The specific
sectors that have been listed, too, are illustrative, i.e. they have been included as
examples, but do not form an exhaustive list. Furthermore, as time goes on, the
general definition of what constitutes a critical infrastructure has expanded from
those vital to the nation’s defense and economic security and continuity of
government (EO13010), to include those vital to public health and safety (National
Plan, Version 1.0), and then again to include those vital to national morale
(Department of Homeland Security supporting document). In concert, the list of
infrastructures to be protected has expanded from those that are primarily necessary
to the function of national defense and the economy (e.g. transportation, energy,
banking and finance), to specific assets that could be used to cause massive
destruction and/or death (e.g. the production, transport, and storage of nuclear
materials, certain biological agents, and hazardous or toxic chemicals), but which
may or may not be critical elements in the nation’s defense or economy. The list
continues to expand to include those assets important to individual communities and
national monuments or icons (National Strategy for Homeland Security). Without
a more rigorous process for identifying critical infrastructure, the list may keep
changing, or growing, or there may exist multiple lists.
Should Congress care if the list of infrastructures remains fluid? One possible
issue is that a vague understanding of what constitutes a critical infrastructure could
lead to vague and diffuse policies and actions. At the very least, a growing list of
infrastructures in need of protection implies a growing commitment on the part of the
federal government. The legislation being debated and the National Strategy both
commit the federal government to interact with each critical infrastructure, to support
and maintain a database on vulnerabilities, to integrate the data base with threat
analyses, to monitor incidents on each of the infrastructures, and to release warnings
as appropriate. Just this will require time and resources. While the cost of adding
additional infrastructures to the list may be marginal, it will not be zero. The federal
government may also be asked to assist financially in affecting necessary protective
measures, not only for infrastructure owned and operated at the state or local level,

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but also for privately owned and operated infrastructures.28 It is not yet clear the
amount of resources required or available. There will probably be a need to prioritize
effort, to allocate limited resources in a way that can minimize the impact of any
future terrorist attacks on the nation’s infrastructure. The Administration alludes to
the need to set priorities throughout the National Strategy.
Essentially, the problem facing the federal government is to minimize, with a
limited amount of resources, the expected impact on the nation’s critical
infrastructure of any future terrorist attack. Impacts could be measured in lives lost,
economic dislocations, loss of military capability, loss of national morale (measured
perhaps by polling), or some combination. Expected impacts are determined by
factoring in the likelihood of various events happening. This is important since
policy makers must balance those scenarios with a low probability of occurring, but
which, if they did occur, could be catastrophic with scenarios that are less
catastrophic, but could happen more easily.
There are a number of ways policy makers may try to prioritize their efforts. As
discussed above, some elements within a critical infrastructure are far more critical
than others. Some elements, or portions of an infrastructure, may be lightly used or
somewhat redundant. If these segments were unavailable, their loss would be an
inconvenience, but such a loss would hardly be ruinous. One option, therefore,
would be to focus on identifying the truly critical assets and doing things to harden
(or toughen) them against attack or to reduce the impact of their loss, either by
building in redundancies or through relocation or redesign (to reduce associated
hazards) over time.
Another possible way of prioritizing resource allocations is to identify
vulnerabilities or solutions that cut across more than one infrastructure. To some
extent, information systems are a common vulnerability to many of the other
infrastructures. Solutions to information system vulnerabilities could be applied
generally, whether it is establishing and implementing best practices or developing
more secure software. Another related technology that cuts across more than one
infrastructure are remote control systems. Much attention has already been focused
on the vulnerabilities of supervisory control and data acquisition systems (SCADAs)
used in energy, water, transportation, and chemical infrastructures.29
Another way is to identify interdependencies between infrastructures. None of
the infrastructures mentioned above are completely isolated from the others. Energy
production depends on transportation. Transportation depends on energy. They both
depend on information networks. Information networks depend on energy. It is
because of these interdependencies that an attack on one segment of an infrastructure
28 Op. cit. National Strategy. p.33-34. The Strategy states that the national infrastructure
protection plan called for by the Strategy will describe how to use all policy instruments to
raise security levels. These could include federal grants to states and localities and, perhaps,
“legislation to create incentives for the private sector to adopt security measures or invest
in improved safety technologies.”
29 See CRS Report RL31534, Critical Infrastructure, Remote Control Systems, and the
Terrorist Threat, by Dana Shea.

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could have a debilitating impact on other infrastructures. Identifying and focusing
on those assets that connect one infrastructure to another may be a cost-effective way
to reduce the overall impact of an attack. The National Infrastructure Simulation and
Analysis Center, established in the USA Patriot Act,30 and slated to be transferred to
the Critical Infrastructure Protection function of the new Department of Homeland
Security, has this as one of its major tasks.
Similarly, there may be geographic locations where a number of critical assets
of one or more infrastructures are located that might warrant priority. One of the
impacts associated with the attacks on the World Trade Center was that the area
housed a number of assets associated with banking and finance, electric power, and
telecommunications, some of which had no backup assets located elsewhere. While
the impacts associated with the loss of these assets were fairly localized to lower
Manhattan, or the services were quickly reconstituted elsewhere, the issue of co-
location of critical assets was not lost on people responsible for ensuring services.
Another possible way to prioritize, at least with regard to the expenditure of
federal resources, is for the federal government to focus more on those infrastructures
that are either entirely owned and operated by the government, or on those private or
local infrastructures upon which the federal government depends to carry out its
activities, or with which the federal government has a long and close working
tradition. This implies letting those infrastructures where the federal government has
not been particularly active to take primary responsibility for addressing their own
vulnerabilities and impacts.
While the definition of critical infrastructure is broad and the number of
infrastructures that are being considered critical has grown, limiting the number of
infrastructures under study a priori might miss a dangerous vulnerability. At some
point, however, priority of effort will be required. According to the National Strategy
for Homeland Security, the federal government will apply a consistent methodology
to focus its efforts on the highest priorities. The Strategy further states that a
forthcoming comprehensive national plan to protect critical infrastructure from
terrorist attacks will provide an approach for rationally balancing the costs and
benefits of increased security according to the threat. However, the Strategy gives
no indication of what these methodologies or approaches will be. Congress may
want to focus some of its attention on how the Administration proposes to set
priorities and what criteria it uses to do so.
30 Op. Cit. USA Patriot ACT. P.L. 107-56. Sec. 1016.

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Appendices
What is Infrastructure?
The President’s proposal to create a Department of Homeland Security which
would, among other responsibilities, assess and develop plans for protecting
America’s critical infrastructure and key assets is focusing attention on the question
of which systems or sectors should be included.
Before “critical infrastructure” became a term of interest in the terrorism and
homeland security debate, the seemingly similar term “infrastructure” was a subject
debated by public policymakers. With no standard or agreed definition, the concept
in policy terms has been fluid, as it appears to be today, including both public and
private systems, services, and even amenities. Nearly 20 years ago, infrastructure
was debated because of concern that the nation’s public works infrastructure was
believed to be suffering from severe problems of deterioration, technological
obsolescence, and insufficient capacity to serve future growth. Unlike today’s focus
on security from physical or cyber attacks on systems, the focus of debate at that time
was the nature, extent, and severity of poor physical condition, technological
adequacy, and capacity of public works systems and about decisions by government
at all levels on spending priorities to meet physical and management needs.
Public and private reports at the time analyzed and critiqued the issue, and many
sought to define the term “infrastructure.” One of these reports, issued by the
Council of State Planning Agencies, defined the term as public service and
production facilities, which include “a wide array of public facilities and equipment
required to provide social services and support private sector economic activity.”
According to this report, infrastructure commonly included roads, bridges, water and
sewer systems, airports, ports, and public buildings, and may also include schools,
health facilities, jails, recreation facilities, electric power production, fire safety, solid
waste disposal, and telecommunications.31
In a 1983 report to Congress about policies regarding the condition of the
nation’s infrastructure, the Congressional Budget Office (CBO) analyzed seven
categories of infrastructure: highways, public transit systems, wastewater treatment
works, water resources, air traffic control, airports, and municipal water supply.
These seven systems, CBO said, “share the common characteristics of capital
intensiveness and high public investment at all levels of government. They are,
moreover, directly critical to activity in the nation’s economy.” CBO noted that “the
concept of infrastructure can be applied broadly to include such social facilities as
schools, hospitals, and prisons, and it often includes industrial capacity, as well.”32
31 Vaughan, Roger, and Robert Pollard. REBUILDING AMERICA, VOL. I, PLANNING AND
MANAGING PUBLIC WORKS IN THE 1980S. Council of State Planning Agencies. Washington
DC, 1984: 1-2.
32 U.S. Congressional Budget Office. Public Works Infrastructure: Policy Considerations
for the 1980s. April 1983: 1.

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In a 1988 report, CBO utilized a similar but consolidated categorization of
infrastructure (highways, aviation, mass transit, wastewater treatment, and water
transportation) based on a definition that those facilities:
provide a foundation or basic framework for the national economy, and in which
federal policy plays a significant role...This definition excludes some facilities
often thought of as infrastructure–such as public housing, government buildings,
private rail service, and schools–and some environmental facilities (such as
hazardous or toxic waste sites) where the initial onus of responsibility is on
private individuals.33
Congress has on many occasions enacted legislation affecting one or more
infrastructure categories, such as surface transportation or water resources, but has
rarely done so comprehensively. During the 1980s debate about deteriorating public
works systems, Congress did enact a bill that established a National Council on
Public Works Improvement with a mandate to analyze and report to Congress and the
President on the state of public works infrastructure systems (P.L. 98-501). Title II
of that act directed the President to submit certain budgetary information on public
civilian and military capital investment programs in the annual budget transmittal.
The coverage of this analysis was to be broad. According to the legislation, it was
to include “any physical asset that is capable of being used to produce services or
other benefits for a number of years” and was to include but not be limited to
“roadways or bridges; airports or airway facilities; mass transportation systems;
wastewater treatment or related facilities; water resources projects; hospitals;
resource recovery facilities; public buildings; space or communication facilities;
railroads; and federally assisted housing.”34
The Council established by P.L. 98-501 provided yet another definition of
infrastructure and included nine categories of systems in its analyses: highways,
streets, roads, and bridges; airports and airways; public transit; intermodal
transportation (the interface between modes); water supply; wastewater treatment;
water resources; solid waste; and hazardous waste services. These categories, the
Council said, have strong links to economic development and generally have a
tradition of public sector involvement. Facilities have high fixed costs and long
economic lives. Taken as a whole, according to the Council, the services that they
provide “form the underpinnings of the nation’s defense, a strong economy, and our
health and safety.”35
Since the 1980s, policymakers’ attention has largely moved away from
considering the infrastructure issue comprehensively and as it was framed during that
earlier period. Legislative proposals generally have addressed meeting the needs of
individual sectors and defining the federal government’s role, especially concerning
33 U.S. Congressional Budget Office. New Directions for the Nation’s Public Works.
September 1988: xi-xii.
34 P.L. 98-501, sec. 203.
35 National Council on Public Works Improvement. Fragile Foundations: A Report on
America’s Public Works, Final Report to the President and Congress. Washington D.C.
February 1988: 33.

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financing. As discussed in this report, the term “critical infrastructure” evolved more
recently, and it occurred separately from policies affecting more specific
infrastructure issues such as highways and airports. Nonetheless, many of the
definitional phrases from the 1980s’ debate about infrastructure–that which is
“directly critical to activity in the nation’s economy” and forms “the underpinnings
of the nation’s defense”–are echoed in today’s discussion of assessing infrastructures
and assets that are critical to homeland security.
How the Criteria and Components of Critical Infrastructure
Have Expanded Over Time
The table below illustrates how the criteria and components of critical
infrastructure have expanded over time. As discussed in the body of this report, for
an infrastructure to be judged critical it must be vital to one or more broad national
functions. That set of functions has expanded over time, beginning with national
defense and economic security, to include public health and safety, and then national
morale. This expansion is noted horizontally, from left to right, in the table below.
Similarly, the components (or sectors) that have been identified specifically as critical
infrastructures has expanded. The expansion of this list is depicted vertically, from
top to bottom, in the table below.
The cross-referencing marks, “x”, are only meant to be illustrative, and
generally coincide with when the specific infrastructure appears on a list. For
example, the chemical industry was not on any list of critical infrastructures when the
criteria were limited to being vital to national or economic security. It appeared after
September 11, 2001, when attention shifted from the more strategic thinking of
earlier policy deliberations to the more immediate concern of preventing large single
event casualties (more a public health and safety concern). That is not to say that the
chemical industry, as a whole, is not an important element in the U.S. economy or
that there may not be a unique facility whose loss of operations might have a ripple
effect through the economy.

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Table 1. What Constitutes Critical Infrastructure Over Time
Infrastructure
Criteria for Being Considered Critical. Vital to ....
national
economic
public health
national
defense
security
and safety
morale
telecommunications
x
x
information networks
energy
x
x
banking/finance
x
transportation
x
x
water
x
emergency services
x
government
x
health services
x
national defense
x
foreign intelligence
x
law enforcement
x
foreign affairs
x
nuclear facilities, in
x
addition to power
plants
special events
x
food/agriculture
x
manufacturing
x
chemical
x
defense industry
x
postal/shipping
x
national monuments
x
icons