High Altitude Electromagnetic Pulse (HEMP) and High Power Microwave (HPM) Devices: Threat Assessments

High Altitude Electromagnetic Pulse (HEMP) and
High Power Microwave (HPM) Devices:
Threat Assessments
Updated July 21, 2008
Clay Wilson
Specialist in Technology and National Security
Foreign Affairs, Defense, and Trade Division

High Altitude Electromagnetic Pulse (HEMP) and High
Power Microwave (HPM) Devices: Threat Assessments
Electromagnetic Pulse (EMP) is an instantaneous, intense energy field that can
overload or disrupt at a distance numerous electrical systems and high technology
microcircuits, which are especially sensitive to power surges. A large scale EMP
effect can be produced by a single nuclear explosion detonated high in the
atmosphere. This method is referred to as High-Altitude EMP (HEMP). A similar,
smaller-scale EMP effect can be created using non-nuclear devices with powerful
batteries or reactive chemicals. This method is called High Power Microwave
(HPM). Several nations, including reported sponsors of terrorism, may currently
have a capability to use EMP as a weapon for cyber warfare or cyber terrorism to
disrupt communications and other parts of the U.S. critical infrastructure. Also,
some equipment and weapons used by the U.S. military may be vulnerable to the
effects of EMP.
The threat of an EMP attack against the United States is hard to assess, but some
observers indicate that it is growing along with worldwide access to newer
technologies and the proliferation of nuclear weapons. In the past, the threat of
mutually assured destruction provided a lasting deterrent against the exchange of
multiple high-yield nuclear warheads. However, now even a single, low-yield
nuclear explosion high above the United States, or over a battlefield, can produce a
large-scale EMP effect that could result in a widespread loss of electronics, but no
direct fatalities, and may not necessarily evoke a large nuclear retaliatory strike by
the U.S. military. This, coupled with published articles discussing the vulnerability
of U.S. critical infrastructure control systems, and some U.S. military battlefield
systems to the effects of EMP, may create a new incentive for other countries to
rapidly develop or acquire a nuclear capability.
Policy issues raised by this threat include (1) what is the United States doing to
protect civilian critical infrastructure systems against the threat of EMP, (2) could
the U.S. military be affected if an EMP attack is directed against the U.S. civilian
infrastructure, (3) are other nations now encouraged by U.S. vulnerabilities to
develop or acquire nuclear weapons, and (4) how likely are terrorist organizations to
launch a smaller-scale EMP attack against the United States?
This report will be updated as events warrant.

Background ......................................................1
The EMP Commission..........................................2
2008 Report on Critical Infrastructure Vulnerabilities.................3
Private Sector and State Government Poorly Prepared.................4
Inaction May Increase EMP Threat to the United States................5
Electromagnetic Pulse Overview..................................6
Description of High-Altitude Electromagnetic Pulse ..................6
Description of High-Power Microwaves............................8
Disruptive Effects of EMP.......................................9
Recovery After Attack.........................................10
Economic Damage Estimates after Attack on Washington, D.C., Region.11
Portable Data Centers and Hardening Against EMP..................12
DOD Vulnerabilities and Research...............................14
Ground Wave Emergency Network...............................16
EMP Capabilities of Other Nations...............................16
Policy Analysis...................................................18
Preparedness ................................................18
Department of Homeland Security................................19
Nuclear Incentive.............................................20
Terrorists ...................................................20
Human Rights...............................................21
Legislative Activity...............................................21
CRS Products....................................................22
List of Figures
Figure 1. Estimated Area Affected by High-Altitude EMP.................7
List of Tables
Table 1. Estimates of Damage and Recovery Times After HEMP Attack
on Washington, D.C., Regional Area..............................12

High Altitude Electromagnetic Pulse (HEMP)
and High Power Microwave (HPM) Devices:
Threat Assessments
A Commission to Assess the Threat from High Altitude Electromagnetic Pulse
(EMP commission) was established by Congress in FY2001 after several experts
expressed concern that the U.S. critical infrastructure and military were vulnerable
to EMP attack.1 On July 20, 2008, the Commission presented a report to the House
Armed Services Committee (HASC) assessing the effects of an EMP attack on U.S.
critical national infrastructures. The 2008 report contained analysis of results of tests
for modern electronics and telecommunications equipment for public networks
supported by the power grid and by temporary isolated power supplies, including cell
phones, computer servers, and Internet routers and switches. The report also made
recommendations for preparation, protection, and recovery of U.S. critical
infrastructures from EMP attack.
The Commission reported that the ubiquitous dependency of society on the
electrical power system, coupled with the EMP’s particular damage mechanisms,
creates the possibility of long-term, catastrophic consequences for national security.
Comparison was made to hurricane Katrina in 2005, where the protracted power
blackout exhausted the limited fuel supplies for emergency generators. However, in
the case of an EMP attack, a widespread collapse of the electric power grid could
lead to cascading effects on interdependent infrastructures, possibly lasting weeks or
months. The Commission stated, “Should significant parts of the electrical power
infrastructure be lost for any substantial period of time ... many people may
ultimately die for lack of the basic elements necessary to sustain life in dense urban
and suburban communities ... [and] the Federal Government does not today have
sufficiently robust capabilities for reliably assessing and managing EMP threats.”2
At a prior hearing, on July 22, 2004, panel members from the EMP commission
stated that as U.S. military weapons and control systems become more complex, and
as portions of the military’s administrative communications systems continue to rely
on the U.S. civilian infrastructure for support, they may be increasingly vulnerable
to the effects of EMP. The consensus of the Commission in 2004 was that a large-

1 Michael Sirak, “U.S. vulnerable to EMP Attack,” Jane’s Defence Weekly, July 26, 2004,
[ h t t p : / / www.j a nes.com/ def e nce/ news/ j dw/ j dw040726_1_n.sht ml ] .
2 Report of the Commission to Assess the Threat to the United States from Electromagnetic
Pulse (EMP) Attack; Critical National Infrastructures, Apr 2008, pp.vi-viii, and p. 79.

scale, high-altitude EMP attack could possibly cause widespread damage to
unprotected civilian and military electronic equipment for an extended period.3
However, the consensus of the EMP commission in 2008 was that the United
States need not remain vulnerable to catastrophic consequences of an EMP attack,
and that the nation’s vulnerability can be reasonably reduced by coordinated and
focused effort between the private and public sectors. The Committee stated that the
cost for improved security in the next three to five years would be modest, especially
when compared with the costs associated with the war on terror and the value of the
national infrastructures threatened.4
The EMP commission’s reports in both 2004 and 2008 focused only on the
effects of High Altitude EMP (HEMP), and not necessarily the effects High Power
Microwave (HPM) devices, which are non-nuclear Radio-Frequency (RF) weapons
that can also produce damaging EMP, but with different characteristics and covering
a smaller geographic area. Both types of EMP are discussed below.
The widely published vulnerability of U.S. civilian and some military
electronics to EMP, along with technical accessibility and lower cost, could make
smaller-scale HPM weapons attractive in the future as weapons for terrorist groups.
Also, some observers argue that unless the United States openly describes how it is
taking action to reduce EMP vulnerabilities within critical infrastructures, perceived
inaction will increase the likelihood that a rogue nation will seek to employ the
asymmetric effects of HEMP against our computer systems.
The EMP Commission
The EMP commission was reestablished by P.L. 109-163, the National Defense
Authorization Act for FY2006. The new Commission to Assess the Threat to the
United States from Electromagnetic Pulse Attack (note that the new title no longer
includes the phrase “High Altitude”, and adds the new word “Attack”) continues with
the same membership, and the Secretary of Defense is authorized to appoint a new
member in the event of a vacancy.5 The EMP commission is tasked to monitor,
investigate, and make recommendations about the vulnerability of electric-dependent
systems of the Department of Defense, government agencies, and the private sector.
On July 22, 2004, members of the EMP commission testified before the House
Armed Services Committee and presented a report consisting of the following five
Volume 1 is an unclassified Executive Summary.
Volume 2 is a classified Threat Assessment.
Volume 3 is an unclassified Assessment of the U.S. Critical Infrastructure.

3 Daniel G. Dupont, “Panel Says Society At Great Risk From Electomagnetic Pulse Attack,”
Inside the Pentagon, July 15, 2004, p.1.
4 William Graham, Testimony before the House Armed Services Committee, Jul 10, 2008.
5 P.L. 109-163, Section 1052, reestablishes the EMP commission.

Volume 4 is a classified discussion of Military Topics.
Volume 5 is a classified Assessment of Potential Threats.
The report stated that High Altitude EMP is capable of causing catastrophic
consequences for the nation, and that the current vulnerability of our critical
infrastructures, which depend so heavily on computers and electronics, can both
invite and reward attack if not corrected.6
Specifically referring to the U.S. military, the report states:
... EMP test facilities have been mothballed or dismantled, and research
concerning EMP phenomena, hardening design, testing, and maintenance has
been substantially decreased. However, the emerging threat environment,
characterized by a wide spectrum of actors that include near-peers, established
nuclear powers, rogue nations, sub-national groups, and terrorist organizations
that either now have access to nuclear weapons and ballistic missiles or may have
such access over the next 15 years have [sic] combined to place the risk of EMP
attack and adverse consequences on the U.S. to a level that is not acceptable....
Our increasing dependence on advanced electronics systems results in the
potential for an increased EMP vulnerability of our technologically advanced
forces, and if unaddressed makes EMP employment by an adversary an attractive7
asymmetric option.”
The EMP commission’s 2004 report proposed a five-year plan for protecting
critical infrastructures from EMP and from other large-scale terrorist attacks. The
five-year plan is briefly summarized in Volume 3 of the report. However, some
portions of the five-year plan that are related to military equipment may remain
classified. The Commission is currently preparing a review of the DOD response to
recommendations made in 2004.8
Testimony at the 2004 hearing included questions such as (1) how would the
United States respond to a limited HEMP attack against the U.S. homeland or against
U.S. forces, where there is loss of technology, but no directly caused loss of life; (2)
does the current lack of U.S. preparedness invite adversaries to plan and attempt a
HEMP attack; and (3) are the long-term effects of a successful HEMP attack, leading
to possible widespread starvation and population reduction, potentially more
devastating to the U.S. homeland than an attack by surface nuclear weapons?
2008 Report on Critical Infrastructure Vulnerabilities
The 2008 EMP Commission report discussed vulnerabilities and
interdependencies among 10 U.S. critical infrastructures. Findings showed that only
limited EMP vulnerability testing had previously been done for modern electronic

6 William Graham, et al., Report of the Commission to Assess the Threat to the United States
from Electromagnetic Pulse Attack, Volume 1: Executive Report 2004.
7 William Graham, et. al., Report of the Commission to Assess the Threat to the United
States from Electromagnetic Pulse Attack, Volume 1: Executive Report 2004, p. 47.
8 Personal communication with EMP Commission staff, Mar 26, 2008.

systems that help support these infrastructures. In addition, the Commission
expressed concern that widespread use of automated supervisory and control data
acquisition (SCADA) systems for the critical infrastructure had allowed companies
and agencies to systematically reduce the size of their work forces having the
necessary technical knowledge needed to support manual operations of these
infrastructure control systems, as might be needed during a prolonged emergency.
The Commission concluded, after reviewing national capabilities to manage the
effects of nuclear weapons (and EMP) on modern systems, that “the Country is
rapidly losing the technical competence in this area that it needs in the Government,
National Laboratories, and Industrial Community.”9
Private Sector and State Government Poorly Prepared
Experts on the Commission have asserted that little has been done by the private
sector to protect against the threat from electromagnetic pulse, and that commercial
electronic systems in the United States could be severely damaged by EMP attack.10
Commercial electronic surge arresters commonly used for lightning strikes reportedly
cannot be relied on because most do not clamp fast enough to protect against the
near-instantaneous effects of EMP (see section below on “Electromagnetic Pulse
Overvi ew”).11
In March 2007, a survey of state Adjutants General who oversee National
Guard units throughout the country found that most state-based emergency
responders are not actively preparing against an attack on the United States by
electromagnetic pulse. The survey, entitled “Missile Defense and the Role of the
States”, was conducted jointly by the Anchorage-based Institute of the North and the
Claremont Institute of Claremont, California. Survey questions were sent to
Adjutants General of all 50 states, with more than half responding. Although 96%
of state Adjutants General indicated significant concern over an EMP attack, the
majority had done little or no analysis of the effects of an overhead EMP attack, and
little or no training, or preparation to harden electronic equipment. None of the
Adjutants General surveyed indicated that they were actively involved in a formal
planning process for response to an EMP attack.12

9 Report of the Commission to Assess the Threat to the United States from Electromagnetic
Pulse (EMP) Attack; Critical National Infrastructures, Apr 2008, p.viii.
10 House Armed Services Committee, Committee Hearing on Commission to Assess the
Threat to the United States from Electromagnetic Pulse Attack, July 22, 2004.
11 Army Training Manual 5-692-2, “Maintenance of Mechanical and Electrical Equipment
at Command, Control, Communications, Computers, Intelligence, Surveillance, and
Reconnaissance (C4ISR) Facilities, HEMP Protection Systems, April 15, 2001, Chapter 27.
12 Press release, Survey Finds Nation Vulnerable to EMP Attack: States Not Preparing,
Institute of the North and The Claremont Institute, March 7, 2007,
[http://www.ins titutenorth.org/ servlet/download?id=261].

Inaction May Increase EMP Threat to the United States
Some analysts discount the likelihood of a large-scale EMP attack against the
United States in the near term, and the extent of possible damage, stating that the
critical infrastructure reportedly would survive, and that military communications
would continue to operate and a high percentage of civilian phone calls would
continue to connect. The argument is that limited testing has shown that modern
commercial equipment may be surprisingly resistant to the effects of electromagnetic
pulse, and that some military systems using commercial equipment are also
retrofitted to be made more EMP resistant before they are fielded.13
However, other analysts maintain that some past testing done by the U.S.
military may have been flawed, or incomplete, leading to faulty conclusions about
the level of resistance of commercial equipment to the effects of EMP. These
analysts also point out that EMP technology has been explored by several other
nations, and as circuitry becomes more miniaturized, modern electronics become
increasingly vulnerable to disruption. They argue that, depending on the targeted
area and power of an EMP attack, it could possibly take years for the United States
to recover fully from the resulting widespread damage to electronics and the power
gr i d . 14
Commission members have stated at hearings that, as time passes without a
visible effort to show the world that we are protecting our computer systems and
critical infrastructures, the perceived inaction may actually invite a possible EMP
attack.15 In the past, the threat of mutually assured destruction provided a lasting
deterrent against the exchange of multiple high-yield nuclear warheads. However,
a single, low-yield nuclear explosion high above the United States, or over a
battlefield, can produce a large-scale, high-altitude EMP effect resulting in
widespread loss of electronics, but possibly without direct fatalities. Therefore, an
EMP attack directed against the United States involving no violent destruction, nor
instant death for large numbers of U.S. citizens, may not necessarily evoke massive
nuclear retaliation by the U.S. military, where, for example, large numbers of
innocent civilians of a nation with a rogue leader might be killed. Such a perceived
lower risk of assured destruction by the United States, and widespread knowledge
about the vulnerability of U.S. civilian and military computers to the effects of an

13 Stanley Jakubiak, statement before the House Military Research and Development
Subcommittee, hearing on EMP Threats to the U.S. Military and Civilian Infrastructure,
October 7, 1999.
14 Lowell Wood, Statement before the House Military Research and Development
Subcommittee, hearing on EMP Threats to the U.S. Military and Civilian Infrastructure,
October 7, 1999; Jack Spencer, “America’s Vulnerability to a Different Nuclear Threat: An
Electromagnetic Pulse,” The Heritage Foundation Backgrounder, No.1372, May 26, 2000,
p. 6.; and Carlo Kopp, “The Electromagnetic Bomb — A Weapon of Electrical Mass
Destruction,” Air and Space Power, 1993.
15 U.S. Congress, House Armed Services Committee, Committee Hearing on Commission
to Assess the Threat to the United States from Electromagnetic Pulse Attack, July 22, 2004,
and on July 10, 2008.

EMP attack, could actually create a new incentive for other countries or terrorist
groups to develop, or perhaps purchase, a nuclear capability.
Electromagnetic Pulse Overview
Electromagnetic energy, characterized as weapon potentially threatening to
national security, can be created as a pulse traditionally by two methods: overhead
nuclear burst and microwave emission. High-Altitude Electromagnetic Pulse
(HEMP) is a near-instantaneous electromagnetic energy field that is produced in the
atmosphere by the power and radiation of a nuclear explosion, and that is damaging
to electronic equipment over a very wide area, depending on power of the nuclear
device and altitude of the burst. High-Power Microwave (HPM) electromagnetic
energy can be produced as a near-instantaneous pulse created through special
electrical equipment that transforms battery power, or powerful chemical reaction or
explosion, into intense microwaves that are also very damaging to electronics, but
within a much smaller area. In addition, while HEMP weapons are large in scale and
require a nuclear capability along with technology to launch high altitude missiles,
HPM weapons are smaller in scale, and can involve a much lower level of technology
that may be more easily within the capability of some extremist groups. HPM can
cause damage to computers similar to HEMP, although the effects are limited to a
much smaller area.
Description of High-Altitude Electromagnetic Pulse
HEMP is produced when a nuclear weapon is detonated high above the Earth’s
surface, creating gamma-radiation that interacts with the atmosphere to create an
instantaneous intense electromagnetic energy field that is harmless to people as it
radiates outward, but which can overload computer circuitry with effects similar to,
but causing damage much more swiftly than, a lightning strike.16 The effects of
HEMP became fully known to the United States in 1962 during a high-altitude
nuclear test (code named “Starfish Prime”) over the Pacific Ocean, when radio
stations and electronic equipment were disrupted 800 miles away throughout parts
of Hawaii. The HEMP effect can span thousands of miles, depending on the altitude
and the design and power of the nuclear burst (a single device detonated at an
appropriate altitude over Kansas reportedly could affect all of the continental United17
States), and can be picked up by metallic conductors such as wires, or overhead
power lines, acting as antennas that conduct the energy shockwave into the electronic
systems of cars, airplanes, or communications equipment.

16 A nuclear explosion produces gamma rays, which interact with air molecules in a process
called the Compton effect. Electrons are scattered at high energies, which ionizes the
atmosphere, generating a powerful electrical field. This EMP effect is strongest at altitudes
above 30,000m, and lasts so briefly that current cannot start flowing through a human body
to cause harm to people.
17 The Federation of American Scientists, “Nuclear Weapons EMP Effects,”
[ h t t p : / / www.f a s.or g/ nuke/ i n t r o/ nuke/ emp.ht m] .

Figure 1. Estimated Area Affected by High-Altitude EMP

Source: Heritage Foundation, Jack Spencer, Americas Vulnerability to a Different Nuclear Threat:
An Electromagnetic Pulse, Backgrounder #1372, May 26, 2000, [http://www.heritage.org/Research/
MissileDefense/bg1372.cfm] .
A high altitude nuclear explosion (that creates HEMP) produces three major
energy components that arrive in sequence, and which have measurably different
effects that can be cumulatively damaging to electronic equipment. The first energy
component is the initial energy shockwave, which lasts up to 1 microsecond, and is
similar to extremely intense static electricity that can overload circuitry for every
electronic device that is within line of sight of the burst. A secondary energy
component then arrives, which has characteristics that are similar to a lightning
strike. By itself, this second energy component might not be an issue for some
critical infrastructure equipment, if anti-lightning protective measures are already in
place. However, the rise time of the first component is so rapid and intense that it
can destroy many protective measures, allowing the second component to further
disrupt the electronic equipment.
The third energy component is a longer-lasting magnetohydrodynamic (MHD)
signal, about 1 microsecond up to many seconds in duration. This late time pulse,
or geomagnetic signal, causes an effect that is damaging primarily to long-lines
electronic equipment.
There are two components to this third late time energy pulse, which experts call
“blast” and “heave.” The “blast” results from a distortion of the earth’s magnetic
field lines by the expanding, fully conductive fireball. The “heave” comes from the
heating and ionization of a patch of atmosphere directly below the bomb that rises

and, being conductive, also distorts the earth’s magnetic field. Both of these are
considered MHD signals and are termed “slow” because they depend on the
dynamics of cloud or fireball expansion.
As the fireball expands, a localized magnetic effect builds up on the ground
throughout the length of long transmission lines and then quickly collapses,
producing the MHD “late-time” power surge, which can overload equipment
connected to the power grid and telecommunications infrastructure. This late-time
effect can add to the initial HEMP effect, and systems connected to long-lines power
and communications systems may be further disrupted by the combined effects.
Smaller isolated systems do not collect so much of this third energy component, and
are usually disrupted only by the first energy component of HEMP.18
It is also important to note that this third, late-time pulse depends on the total
energy of the nuclear detonation and therefore is usually associated only with larger
yield nuclear weapons. However, the first energy pulse is a saturation-limited effect
and is produced by all nuclear weapons, both small and large yield.
Description of High-Power Microwaves
Microwaves are characterized by electromagnetic energy with wavelengths as
small as centimeters or millimeters, and can be used at moderate power levels for
radio frequency communications or for radar.19 High-power microwaves can be
created as an instantaneous electromagnetic pulse, for example, when a powerful
chemical detonation is transformed through a special coil device, called a flux
compression generator, into an intense electromagnetic field.20 Other methods can
also be used to create a reusable HPM weapon, such as combining reactive chemicals
or using powerful batteries and capacitors to create EMP. HPM energy can be
focused using a specially-shaped antenna, or emitter, to produce effects similar to
HEMP within a confined area, or over a limited distance. Unlike HEMP, however,
HPM radiation uses shorter wave forms at higher-frequencies which make it highly
effective against electronic equipment and more difficult to harden against. A
mechanically simple, suitcase-sized device, using a chemical explosive and special
focusing antenna, might theoretically produce a one-time, instantaneous HPM

18 The Federation of American Scientists, “Nuclear Weapons EMP Effects,”
[http://www.fas.org/nuke/intro/nuke/emp.htm], and Report of the Commission to Assess the
Threat to the United States from Electromagnetic Pulse (EMP) Attack, Vol.1: Executive
Report 2004, p.5.
19 For example, microwaves with wavelengths about 5.7 cm long (C-band), or 20 cm long
(L-band), or 3 cm long (X-band) are often used for radar or communications.
20 A Flux Compression Generator consists of explosives packed inside a cylinder, all of
which is contained within a cylindrical copper coil structure. The explosive is detonated
from rear to front, causing the tube to flare in a wave that touches the copper coil, which
produces a moving short circuit. This compresses the magnetic field and creates an
electromagnetic pulse that is emitted from the front end, which is then directed by a special
focusing antenna.

shockwave that could disrupt many computers within a 1-mile range.21 Also, HPM
energy at higher power levels (megawatts), and powered for a longer time interval,
reportedly could cause physical harm to persons near the source emitter, or possibly
in the path of a narrowly focused energy beam.22
Disruptive Effects of EMP
Studies related to the effects of electromagnetic energy used as weapons have
been published infrequently, or remain classified.23 Nevertheless, it is known that a
powerful HEMP field as it radiates outward can interfere with radio frequency links
and instantly produce damaging voltage and currents in electronic devices thousands
of miles from the nuclear explosion. Effectiveness is increased if the electronic
devices are connected to any other metal that could also act as an antenna. Because
infrastructure computer systems are interconnected, a widespread HEMP effect could
lead to possible long-term disruption of the power grid, fuel distribution,
transportation systems, food and water supplies, and communications and equipment
for hospitals and first responders, as well as military communications systems which
utilize the civilian infrastructure.
An HPM weapon has a shorter possible range than HEMP, but it can induce
currents large enough to melt circuitry, or it can cause equipment to gradually fail
over a period of minutes, days, or even weeks. In 2001, a U.S. Comanche helicopter,
flying in New York while performing a radar test involving HPM weapons, generated
a low-level energy pulse that reportedly disrupted for two weeks the global
positioning systems (GPS) being used to land commercial aircraft at a nearby airport
in Albany, New York.24
A HEMP attack directed against the Unites States continent might involve a
one-megaton nuclear warhead, or a smaller one, using a burst several hundred miles
above the mid-western states to affect computers on both coasts.25 However, creating
a HEMP effect over an area 250 miles in diameter, an example size for a battlefield,
might only require a rocket with a modest altitude and payload capability that could
loft a relatively small nuclear device. If a medium or higher range missile with a
nuclear payload were launched from the deck of a freighter at sea, the resulting

21 Dr. Robert C. Harney, Naval Postgraduate School, April 12, 2004, personal
22 Victorino Matus, “Dropping the E-bomb,” The Weekly Standard, February 2, 2003,
[http://theweeklyst a n d a rd.com/Utilities/printe r_preview.asp?idAr ticle=2209&R=9F0C22


23 William Graham, Electromagnetic Pulse Threats to U.S. Military and Civilian
Infrastructure, hearing before the Military Research and Development Subcommittee,
House Armed Services Committee, October 7, 1999; and Carlo Kopp, “The
Electromagnetic Bomb — A Weapon of Electrical Mass Destruction,” Air and Space Power.
24 Kenneth R. Timmerman, “U.S. Threatened with EMP Attack,” Insight on the News, May

28, 2001.

25 [http://www.physics.northwestern.edu/classes/2001Fall/Phyx135-2/19/emp.htm].

HEMP could reportedly disable computers over a wide area of the coastal United
The disruptive effects of both HEMP and HPM reportedly diminish with
distance, and electronic equipment that is turned off is only less likely to be
damaged.26 To produce maximum coverage for the HEMP effect, a nuclear device
must explode very high in the atmosphere, too far away from the earth’s surface to
cause injury or damage directly from heat or blast. Also, HEMP produced by the
nuclear explosion is instantaneous — too brief to start current flowing within a
human body — so there is no effect on people. However, microwave energy
weapons (HPM) are smaller-scale, are delivered at a closer range to the intended
target, and can sometimes be emitted for a long duration. These characteristics of
HPM can sometimes cause a painful burning sensation or other injury to a person
directly in the path of the focused power beam, or can even be fatal if a person is too
close to the microwave emitter.27
Both HEMP and HPM can permanently immobilize vehicles with modern
electronic ignition and control systems. However, older electrical components, such
as vacuum tubes and induction coils for spark ignition, are generally built more
massively, and are more tolerant of EMP. As modern electronics shrink in size,
circuitry is becoming increasingly tiny and more vulnerable to electromagnetic
interference. Therefore, countries with infrastructure that relies on older technology
may be less vulnerable to the disabling effects of HEMP or HPM than countries that
rely on a higher level of technology.28
Recovery After Attack
The simultaneous loss of communications and power that would likely result
from an EMP attack would also complicate the restoration of systems. Without
communications, it would be difficult to ascertain the nature and location of damage,
or to order personnel out to make repairs. The estimated recovery times for various
elements of the electrical system are provided in a list that appears on pages 50-51
of the 2008 Commission report.

26 Experts may disagree on whether the damaging effects of HPM actually diminish
following the familiar inverse-square-of-the-distance rule. Michael Abrams, “The Dawn of
the E-Bomb,” IEEE Spectrum, November 2003, [http://www.spectrum.ieee.org/WEBONLY/
publicfeature/nov03/1103ebom.html]. Some experts state that the severity of HEMP effect
depends largely on the bomb design, so a specially-designed low yield bomb may pose a
larger HEMP threat than a high yield bomb. Lowell Wood, statement before the House
Research and Development Subcommittee, hearing on EMP Threats to the U.S. Military and
Civilian Infrastructure, October 7, 1999.
27 Victorino Matus, “Dropping the E-bomb,” The Weekly Standard, February 2, 2003,
[http://theweeklystandard.com/Utilities/printer_preview.as p ? i d Ar ticle=2209&R=9F0C22


28 Lowell Wood, statement before the House Research and Development Subcommittee,
hearing on.EMP Threats to the U.S. Military and Civilian Infrastructure, October 7, 1999.

The report states that the continuing business need to improve and expand the
electric power system provides an opportunity to improve both the security and
reliability of the entire system in an economically acceptable manner.29 The
Commission reported that the seriousness of loss of the electric power grid could be
reduced through focused coordination between industry and government. The
Commission recommended that the federal government, according to standards it
determines, should validate proposed enhancements to protect systems against
damage from EMP attack, and fund those security related elements.
Economic Damage Estimates after Attack on
Washington, D.C., Region
In September 2007, the Sage Policy Group of Baltimore and Instant Access
Networks (IAN) published a study of the potential economic impact of a HEMP
attack on the Baltimore-Washington-Richmond area. The study focuses on the
economic effects of EMP experienced by a region after a high-altitude EMP pulse
generated by a nuclear device detonated between 30-80 miles above ground
impacting an area at least 500 miles in radius. In these instances of high-altitude
EMP, no one would feel the heat or blast but merely experience the effects of the
disruption or damage to the electronic and power infrastructure. The
Baltimore-Washington-Richmond area likely comprises only one-tenth of the
economic loss that would occur for the total geographic area affected by a regional
EMP event.
The report was presents a range of low, medium, and high estimates of
economic damage, all within bounds accepted by a broad range of EMP experts. The
methodology relied on assumptions about disruption and damage to the regional
electrical power system, communications systems, system control and data
acquisition (SCADA) devices, and other critical infrastructure that might occur as a
result of an EMP, and on the time required to repair that damage and fully restore
economic activity. These assumptions were used in combination to estimate the
ultimate effects of an EMP on the region’s economy. The cumulative effect of an
EMP on critical infrastructure was assumed to be largely determined by effects on the
electrical grid and communications systems. Cumulative damage was then
determined by multiplying the remaining capacity of the electrical grid by the
remaining capacity of communication systems under three scenarios. For example,
under the high case, an EMP damages 50% of the capacity of the electric grid and
50% of the capacity of communication systems. The analysis assumed that the
economy was then able to operate at only 25% of capacity (i.e., 50% multiplied by


The study concluded that an EMP attack affecting the Baltimore-Washington-
Richmond region could result in economic output loss potentially exceeding $770
billion, or 7% of the nation’s annual gross domestic product. Even under the most
favorable assumptions, including both shielded and unshielded critical infrastructure,

29 Report of the Commission to Assess the Threat to the United States from Electromagnetic
Pulse (EMP) Attack; Critical National Infrastructures, Apr 2008, p. 52.

an EMP might still result in damage that would require one month of recovery and
economic loss of $9 billion and $34 billion respectively.
Table 1. Estimates of Damage and Recovery Times After HEMP
Attack on Washington, D.C., Regional Area
Midpoint of Replacement Times
Percentage of Capacity Damaged(months)
InfrastructureLow CaseMid CaseHigh CaseLow CaseMid CaseHigh Case
Electric grid
T r ansforme rs 10% 40% 70% 2.5 13.5 33.0
Other 30% 40% 50% 1.5 5.0 10.0
Communications systems
Large 10% 20% 50% 4.0 18.0 27.0
Small 5% 20% 50% 2.0 12.0 17.0
All types5%20%50%
Large 20% 45% 70% 4.0 12.0 17.0
Small 1% 2% 3% 1.5 5.0 10.0
Source: Instant Access Networks and Sage Policy Group,Initial Economic Assessment of
Electromagnetic Pulse (EMP) Impact upon the Baltimore-Washington-Richmond Region,” September
10, 2007, Exhibit 2, p. 5, at [http://www.pti.org/docs-safety/EMPecon_9-07.pdf].
In the worst case, according to the study, not only is the damage from EMP
widespread, but the duration of disrepair lasts for years. In such cases, there are
numerous complicating factors that could slow the recovery process. The quantity
of replacement equipment needed to restore the economy may quickly exhaust
readily available supplies and, in extreme cases, existing manufacturing capacity. In
such cases, the availability of skilled labor to replace and restore key infrastructure
elements may also be in extraordinarily short supply. High-altitude EMP would also
affect much larger parts of the region than the immediate
Baltimore-Washington-Richmond area, further complicating recovery efforts. It is
unlikely that restoration would occur in an orderly, linear fashion. More likely,
restoration efforts would start slowly and gather speed as basic infrastructure is
gradually brought on line.
Portable Data Centers and Hardening Against EMP
Electronic equipment may be made more resistant to EMP by surrounding it
with protective metallic shielding, which routes damaging electromagnetic surges
away from highly sensitive electrical components. This method, commonly known
as Faraday cage protection, is often used to protect electronic equipment from a
lightning strike. However, these devices must be constructed carefully. Any wires

running into the protected area could act as antennae and conduct the electromagnetic
shockwave into the equipment. These points of entry into a shielded area must be
protected from EMP by using specially designed surge protectors, special wire
termination procedures, screened isolated transformers, spark gaps, or other types of
specially designed electrical filters.30 Additionally, an EMP surge from a very
powerful nuclear blast, possibly involving a 200 Kilovolts/meter electric field, could
pass through some protective shielding.31
Microsoft, Sun Microsystems, and other vendors have recently marketed a new
product commonly called a “Portable Data Center” (PDC) where computer
equipment is placed on racks that are pre-grouped inside a modular room, which can
be moved and connected to other portable computer room modules, as needed.32 For
example, a portable module can hold as many as 1,200 servers along with power
supply and a cooling system. All this computer equipment fits into a box that can be
placed inside a 40-foot standard freight shipping container, which can also be
mounted on a truck for portability.33 This new method for housing computers is
intended to reduce the cost for computer facility installation.
However, additional features may also transform a PDC into an effective
method for making U.S. computer equipment less vulnerable to EMP attack. For
example, Instant Access Networks (IAN), a specialized technology vendor, now
offers a portable modular equipment room that reportedly can meet military
specifications for EMP protection.34 The IAN product uses welded metal enclosures
of precise composition and thickness. A recently filed patent application involves
a unique construction method to block different EMP frequencies and also reduce

30 Electrical systems connected to any wire or line that can act as an antenna may be
disrupted. Army Training Manual 5-692-2, April 15, 2001, “Maintenance of Mechanical
and Electrical Equipment at Command, Control, Communications, Computers, Intelligence,
Surveillance, and Reconnaissance (C4ISR) Facilities, HEMP Protection Systems, Chapter


31 Recent Russian military writings claim that they have a Super-EMP weapon that can
generate more than 200 KVs per meter, which is 4 times greater than the level of EMP
hardening tested by the United States. Kilovolts per meter is the standard measure for
describing the strength of an EMP field. In layman’s terms, the statement that a Russian
Super-EMP weapon could generate 200 kilovolts per meter means that a conductive object
exposed to the EMP field will experience a surge of 200,000 volts for every meter of its
length. So if the object is 2 meters long, it gets 400,000 volts. If 3 meters long, it gets
600,000 volts, and so on. Testimony from the EMP Commission before the House Armed
Services Committee, Jul 10, 2008.
32 Rich Miller, Microsoft Mulling Portable Data Centers,
[http://www.dat acent e r knowl e dge.com/ ar chi ves/ 2007/ Apr / 05/ mi cr osoft_mulling_
portable_data_centers.html ].
33 Stephen Shankland, Rackable’s portable data center goes on sale, CnetNews.com, Mar 26,

2007, [http://news.cnet.com/Rackables-portable-data-center-goes-on-sale/

2100-1010_3-6170495.html ].

34 Instant Access Networks, LLC, provides a commercial off-the-shelf, portable data center
that meets or exceeds military specifications for EMP protection.
[ h t t p : / / www.s a f e 9-1-1.c om/ ] .

weight for easier portability. This type of portable module, built and tested according
to strict specifications, could possibly be mass-produced and deployed as an effective
way to protect existing and future U.S. computer systems from EMP attack.35 For
example, a single module placed at a remote critical location could possibly operate
as an EMP-protected SCADA system, or multiple shielded modules could be
connected together at a central headquarters location for a high-capacity protected
DOD has also published Mil-Standard 188-125, which describes methods for
protecting against High-Altitude Electromagnetic Pulse for ground-based command
and control facilities.36 However, not all military systems are currently hardened
against EMP. In addition, some DOD systems rely on commercial facilities, such as
communications satellites and ground-based stations, for support of military
operations. Hardening most military systems, and mass-produced commercial
equipment including PCs and communications equipment, against HEMP or HPM
reportedly would add from 2% to 3% to the total cost, if the hardening is engineered
into the original design. To retro-fit existing military electrical equipment with
hardening would add about 3%-10% to the total cost.37
DOD Vulnerabilities and Research
In 2004, the EMP Commission held the collective the opinion that DOD had not
engaged in any tabletop exercises and simulations that anticipate and EMP attack.
In fact, an EMP commissioner observed that over the past 40 years, DOD has tended
to “not introduce EMP attack into exercise scenarios or game scenarios because it
tends to end the game, and that is not a good sign.”38
In April, 2005, the Defense Science Board (DSB) Task Force on Nuclear
Weapon Effects (NWE) Test, Evaluation and Simulation published a report for DOD
describing current and emerging threat environments. This included a
comprehensive evaluation of future DOD capabilities for successful operation in
nuclear environments. The DSB findings were independent, “but are highly
consistent with, the findings and recommendations of the Congressionally mandated
Electromagnetic Pulse (EMP) Commission.” The DSB findings include the
Despite the reduction of the threat of strategic nuclear exchange, it is becoming
more, not less, likely that U.S. forces will have to operate in a nuclear

35 Charles Manto, et. al., Pending U.S. Patent number 20070105445, “System and Method
for Providing Certifiable Electromagnetic Pulse and RFI Protection Through Mass-Produced
Shielded Containers and Rooms”, published May 10, 2007.
36 MIL-STD-188-125-1, Apr 2005, [http://www.wbdg.org/ccb/FEDMIL/std188_125_1.pdf].
37 Lowell Wood, statement before the House Research and Development Subcommittee,
hearing on EMP Threats to the U.S. Military and Civilian Infrastructure, October 7, 1999.
Personal communication with EMP Commission members, July 2008.
38 Dr. Lowell Wood, testimony before the House Committee on Armed Services, H.A.S.C
No. 108-37, July 22, 2004, p. 23.

environment in regional operations. This is driven by the proliferation of nuclear
weapon capabilities and the attractiveness of nuclear weapons as an offset to
U.S. conventional superiority and as a counter to U.S. preemptive doctrine.
... factors that should make decision makers concerned about the survivability of
critical warfighting elements in a nuclear environment. These include the shift
to commercial-off-the-shelf (COTS) based electronics, aging of key systems, the
growing reliance on historically “soft” C4ISR2 assets, the general neglect of
nuclear hardening as a requirement, and the general neglect of nuclear
environments as a factor in gaming and exercises. The bottom line is that
commanders and planners cannot be assured that today’s weapons platforms,
command and control (C2), intelligence, surveillance and reconnaissance (ISR),
and associated support systems will be available should a nuclear detonation39
Underground testing of nuclear devices done in 1992 at the Nevada Test Site
were designed to research protection techniques to harden military systems against
HEMP effects resulting from a nuclear exchange.40 The Limited Test Ban Treaty of

1963 prohibits nuclear explosions in the atmosphere, in space, and under water.

Since then, testing to calibrate the effects of large-scale HEMP on the critical
infrastructure has been restricted. The design of new simulators to help measure
these effects would call for complex computations to represent the large number of
possible interactions between components found in the circuit boards, network
connections, wireless systems, hardware modules, and operating environments of
modern electronic systems that support the critical infrastructure.
DOD research on pulsed-power HPM electromagnetic weapons is currently
being done at Kirtland Air Force Base, in Albuquerque, New Mexico. Weapons now
being developed by the U.S. military for electronic warfare can disrupt the trajectory
of missiles while in flight, and can overpower or degrade enemy communications,
telemetry, and circuitry. Other HPM weapons being tested by the military are
portable and re-usable through battery-power, and many are effective when fired
miles away from a target. These weapons can also be focused like a laser beam and
tuned to an appropriate frequency in order to penetrate electronics that are heavily
shielded against a nuclear attack. The deepest bunkers with the thickest concrete
walls reportedly are not safe from such a beam if they have even a single unprotected
wire reaching the surface.41
Because instantaneous HPM energy can reflect off the ground and possibly
affect piloted aircraft above, much testing currently involves HPM devices on
Unmanned Aerial Vehicles (UAVs), and on the Air Force Conventional Air-
Launched Cruise Missile system. By 2010, DOD reportedly will field several air-

39 Report of the Defense Science Board Task Force on Nuclear Weapon Effects Test,
Evaluation, and Simulation, April 2005, at [http://www.acq.osd.mil/dsb/reports/


40 Associated Press, “Experts Cite Electromagnetic Pulse as Terrorist Threat,” Las Vegas
Review-Journal, October 3, 2001.
41 Michael Abrams, The Dawn of the E-Bomb, IEEE Spectrum Online, November 2003,
[ h t t p : / / www.spect r u m. i e ee.or g/ WEBONLY/ publ i c f eat ur e/ nov03/ 1103ebom.ht ml ] .

launched UAVs using disposable and reusable HPM weapons designed to disrupt
enemy computers.42
Ground Wave Emergency Network
During the Cold War, the US Military designed an innovative communications
system to relay emergency messages between strategic military areas in the
continental United States, using signals that travel by means of low frequency ground
waves — electromagnetic fields that hug the ground — rather than by radiating into
the atmosphere. The Ground Wave Emergency Network, or GWEN system, was
intended to allow continuous communications despite EMP disruptions. However,
the hardware was reportedly transistor based, leaving the system with some level of
vulnerability to EMP. In addition, the fixed locations of GWEN sites were known
to adversaries, and thus vulnerable to direct attack.43
As the Cold War ended, the U.S. military took steps to reduce its nuclear arsenal
and associated infrastructure.44 After 1998, the USAF decommissioned GWEN
assets and replaced the entire system with the Single Channel Anti-Jam Man-Portable
(SCAMP) Terminal. SCAMP uses extremely high frequency (EHF) technology, is
resistant to EMP, and offers more flexibility than GWEN because the equipment is
lightweight, transportable, and interoperable with DOD satellite networks.45
EMP Capabilities of Other Nations
Reportedly, several potential U.S. adversaries, such as Russia or China, are now
capable of launching a crippling HEMP strike against the United States with a
nuclear-tipped ballistic missile, and other nations, such as North Korea, could46
possibly have the capability by 2015. Other nations that could possibly develop a
capability for HEMP operations over the next few years include United Kingdom,
France, India, Israel, and Pakistan.

42 David Fulghum and Douglas Barrie Farnboruogh, “Directed-Energy Weapon for UAV,
cruise and air-to-ground missile payloads nears production,” Aviation Week & Space
Technology, July 26, 2004, p. 34.
43 Rosalie Bertell, “Background on the HAARP Project,” Global Policy Forum, November

5, 1996, [http://www.globalpolicy.org/socecon/envronmt/weapons.htm].

44 Admiral Richard W. Mies, Commander in Chief, United States Strategic Command,
statement before the Senate Armed Services Committee Strategic Subcommittee on
Command Posture, July 11, 2001, p.11, [http://www.defenselink.mil/dodgc/lrs/-
45 Federation of American Scientists, AN/PSC-11 Single Channel Anti-Jam Man-Portable
(SCAMP)Terminal, March 2000 [http://www.fas.org/spp/military/program/com/an-psc-11
46 Michael Sirak, “U.S. vulnerable to EMP Attack,” Jane’s Defence Weekly, July 26, 2004,
[http://www.janes.com/defence/news/jdw/jdw040726_1_n.shtml], and House Armed
Services Committee, hearing on Commission to Assess the Threat to the United States from
Electromagnetic Pulse Attack, July 22, 2004.

In 2005, Iran reportedly acquired several medium and intermediate-range
ballistic missiles from North Korea, with a range of 2,500 miles.47 In 2006, Iran
tested several of their Shahab-3 nuclear-warhead-capable ballistic missiles, which
were exploded in mid-flight. While these explosions could have been the result of
a missile self-destruct mechanism, Iran has officially described the tests in 2006 as
fully successful. It was noted by witnesses at a 2005 hearing of the Senate
Committee on the Judiciary, Subcommittee on Terrorism, Technology and Homeland
Security, that this event could indicate that Iran may be practicing for the execution
of an HEMP attack.48 In July 2008, Iran test-launched several more long-range
ballistic missiles. However, other observers caution that these and similar actions
might simply be a scare tactic used by Iran, but without much substance.49
A discussion of asymmetric warfare and anti-satellite weapons, at a June 25,
2008, hearing by the House Armed Services Committee, included the possible
example of the United States being targeted for attack by China using EMP.50
According to a 1999 DOD report, China has been actively pursuing the development
of electromagnetic pulse weapons, and has devoted significant resources to
development of other electronic warfare systems and laser weapons. The report also
noted that China’s leaders view offensive counter space weapons and other
space-based defense systems as part of inevitable scenarios for future warfare. The
report noted that China could have as many as 60 ICBMs capable of striking the
United States by 2010. Also, China may replace 20 of its current ICBMs with a
longer-range missile by the end of this decade, or sooner.51
Vladimir Lukin, the former Soviet Ambassador to the United States, and former
Chairman of the International Affairs Committee for the Russian Parliament,
reportedly has stated that Russia currently has a capability to create a HEMP effect
over the United States.52 During 1962, the then Soviet Union conducted a series of

47 Alon Ben-David, Iran Acquires Ballistic Missiles from DPRK, Jane’s Intelligence and
Oversight, December 29, 2005.
48 Senate Committee on the Judiciary, Subcommittee on Terrorism, Technology and
Homeland Security, March 8, 2005. Jane’s Information Group, Shahab break-ups suggest
possible EMP trial , May 1, 2005, Jane’s Rockets and Missiles. Joseph Farah, Iran plans
to knock out U.S. with 1 nuclear bomb, April 25, 2005, WorldNewsDaily.com,
[http://wnd.com/news/article.asp?ART ICLE_ID=43956].
49 Officials in Iran have also reported that in March 2006, they successfully tested their
“Fajr-3” long-range missile, which they claim has a range of 2000 miles, and which is
invisible to radar. However, other intelligence sources reportedly argue that the “Fajr-3”
is merely an upgraded artillery shell with a very short range. “Iran Claims Test of Fajr-3
Missile ‘Invisible’ to Radar, Interceptors”, April 3, 2006, MissileThreat.com,
[ h t t p : / / www.mi ssi l e t h r e at .com/ n ews/ 200604030826.ht ml ] .
50 Testimony of James Shinn, Assistant Secretary of Defense, Security Developments in
China, hearing before the House Armed Services Committee, June 25, 2008.
51 FY04 Report to Congress on PRC Military Power, Annual Report on The Military Power
of the People’s Republic of China, [http://www.defenselink.mil/pubs/d20040528PRC.pdf].
52 The statement was reportedly made on April 30, 1999, to a U.S. Congressional delegation

atmospheric nuclear tests and observed HEMP effects that included surge protector
burnouts, power supply breakdowns, and damage to overhead and underground
buried cables at distances of 600 kilometers. Since then, Russia has reportedly made
extensive preparations to protect their infrastructure against HEMP by hardening
both civilian and military electronic equipment, and by providing continuous training
for personnel operating these protected systems.53 Other sources have reportedly
stated that Russia may also have some of the leading physicists in the world currently
doing research on electronic warfare weapons and electromagnetic pulse effects.54
Policy Analysis
What is the United States doing to protect critical infrastructure systems against
the threat of electromagnetic pulse? What is the appropriate response from the
United States to a nuclear HEMP attack, where there may be widespread damage to
electronics, but relatively little, or possibly no loss of life as a direct result? How
could the United States determine which nation or group launched a HEMP attack?
After experiencing a HEMP effect, the United States may retain its capability to use
strategic weapons for nuclear retaliation, but will the U.S. industrial base and critical
infrastructure be crippled or incapable of supporting a sustained military campaign?
During such time, would the United States be capable of a making an effective
response should other nations chose to make military advances in other parts of the
A large percentage of U.S. military communications during Operation Iraqi
Freedom was reportedly carried over commercial satellites, and much military
administrative information is currently routed through equipment that comprises the
civilian Internet.55 Many commercial communications satellites, particularly those
in low earth orbit, reportedly may degrade or cease to function shortly after a high

52 (...continued)
that traveled to Vienna to meet with officials from the Russian Duma to discuss a framework
for a peaceful solution of the then crisis in Kosovo. Hearing before the Military Research
and Development Subcommittee of the Committee on Armed Services House of
Representatives, October 7, 1999, [http://commdocs.house.gov/committees/security/-
has280010.000/has280010_0.HTM ].
53 Lowell Wood, statement before the House Research and Development Subcommittee,
hearing on EMP Threats to the U.S. Military and Civilian Infrastructure, October 7, 1999.
54 Barry Crane, a physicist and former F-4 pilot now working at the Institute for Defense
Analysis, has visited Russia’s top electromagnetic pulse laboratories and design bureaus,
and has stated that many Russian electromagnetic pulse specialists may also be now working
on contract in China. Kenneth R. Timmerman, May 28, 2001, “U.S. Threatened with EMP
Attack,” Insight on the News.
55 Jefferson Morris, “DISA Chief Outlines Wartime Successes,” Federal Computer Week,
June 6, 2003; and “GAO: DOD Needs New Approach to Buying Bandwidth,” Aerospace
Daily, December 12, 2003.

altitude nuclear explosion.56 Many commercial satellite control stations on the
ground may also degrade after an EMP attack. However, some observers believe that
possible HEMP and HPM vulnerabilities of military information systems are
outweighed by the benefits gained through access to innovative technology and
increased communications flexibility that come from using state-of-the-art
electronics and from maintaining connections to the civilian Internet and satellite
The effects of large-scale HEMP have been studied over several years by the
Defense Atomic Support Agency, the Defense Nuclear Agency, and the Defense
Special Weapons Agency, and are currently being studied by the Defense Threat
Reduction Agency (DTRA). However, the application of the results of these studies
has been uneven across military weapons and communications systems. Some
analysts argue that U.S. strategic military systems (intercontinental ballistic missiles
and long-range bombers) may have strong protection against HEMP, while many
other U.S. weapons systems used for the battlefield have less protection, and that this
is undoubtedly known to our potential adversaries.57
Some analysts reportedly state that limited testing has shown modern
commercial equipment may be surprisingly resistant to the effects of electromagnetic
pulse, and some military systems using commercial equipment have been retrofitted
to increase resistance to EMP.58 However, there is disagreement among observers
about whether the procedures used by the U.S. military to test EMP survivability may
have been flawed, leading to erroneous conclusions about the effects of
electromagnetic pulse on commercial electronics.59
Department of Homeland Security
As part of its risk analysis mission, the Department of Homeland Security
(DHS) has developed a set of 15 National Planning Scenarios, which depict a diverse
set of high-consequence threat scenarios of both potential terrorist attacks and natural
disasters. These 15 scenarios are designed to focus contingency planning for

56 U.S. Congress, House Armed Services Committee, Hearing on Commission to Assess the
Threat to the United States from Electromagnetic Pulse Attack, July 22, 2004.
57 Because of the very specialized nature, strategic weapons use essentially no commercial
equipment. However, DOD increasingly uses commercial equipment in other tactical
weapons. Stanley Jakubiak and Lowell Wood, statements before the House Military
Research and Development Subcommittee, hearing on EMP Threats to the U.S. Military and
Civilian Infrastructure, October 7, 1999.
58 Stanley Jakubiak, statement before the House Military Research and Development
Subcommittee, Hearing on EMP Threats to the U.S. Military and Civilian Infrastructure,
October 7, 1999.
59 Lowell Wood, statement before the House Military Research and Development
Subcommittee, hearing on EMP Threats to the U.S. Military and Civilian Infrastructure,
October 7, 1999; and Jack Spencer, “America’s Vulnerability to a Different Nuclear Threat:
An Electromagnetic Pulse,” The Heritage Foundation Backgrounder, No.1372, May 26,
2000, p.6.; and Carlo Kopp, “The Electromagnetic Bomb — A Weapon of Electrical Mass
Destruction,” Air and Space Power 1993.

homeland security preparedness work, at all levels of government, and with the
private sector. These scenarios form the basis for coordinated federal planning,
training, exercises, and grant investments needed to prepare for emergencies of all
types.60 However, EMP Commission members stated at the 2008 HASC hearing that
they have been unable to convince DHS to add EMP attack to its list of National
Planning Scenarios.61
Nuclear Incentive
A single nuclear device exploded at an appropriate altitude above the
continental United States could possibly affect our industrial capacity, economic
stability, and military effectiveness. Does knowledge of this vulnerability, combined
with the proliferation of nuclear technology, provide a new incentive for potential
adversaries to develop or acquire a nuclear weapons capability? Will countries now
view the development and acquisition of nuclear weapons, even a small arsenal, as
a strategy for cyber warfare?
During the Cold War, a HEMP attack was viewed as the first step of a nuclear
exchange involving many warheads, but the threat of mutually assured destruction
provided a lasting deterrent. Today, the proliferation of nuclear technology makes
the threat of HEMP attack more difficult to assess. Would the leader of a rogue state
be motivated to use a small nuclear arsenal to launch a crippling HEMP strike against
the United States, with no resulting fatalities, if it believed the U.S. likely would not
retaliate with a nuclear salvo, destroying thousands, or millions of innocent people?
Would a HEMP strike over a disputed area during a regional conflict be seen as a
way to defeat the communications links and network centric capability of the U.S.
military, and gain battlefield advantage from an existing supply of smaller nuclear
warheads? 62
A smaller-scale HPM weapon requires a relatively simple design, and can be
built using electrical materials and chemical explosives that are easy to obtain. It is
estimated that a limited-range suitcase-sized HPM weapon could be constructed for
much less than $2,000, and is within the capability of almost any nation, and perhaps63
many terrorist organizations. In 2001, DOD recruited a scientist to create two small

60 Department of Homeland Security, National Preparedness Guidelines, September 2007,
Fig. B-1, p.31, [http://www.dhs.gov/xlibrary/assets/National_Preparedness_Guidelines.pdf].
61 William Graham, testimony before the House Armed Services Committee, July 10, 2008.
62 Jack Spencer, “America’s Vulnerability to a Different Nuclear Threat: An
Electromagnetic Pulse,” The Heritage Foundation Backgrounder, No.1372, May 26, 2000,
p. 3.
63 Some experts may disagree about whether most terrorist organizations are capable of
building an inexpensive HPM weapon powered by a flux-compression generator. Michael
Abrams, “The Dawn of the E-Bomb,” IEEE Spectrum Online, November 2003,
[http://www.spectrum.ieee.org/WEBONLY/publicfeature/nov03/1103ebom.html], and Carlo

HPM weapons for testing using only commercially available electrical components,
such as ordinary spark plugs and coils. One device was developed that could be
broken down into two parcels so it could be shipped by regular mail, for example,
from one terrorist to another. The second HPM device was constructed to fit inside
a small vehicle.64 Currently, HPM devices, including suitcase-sized devices powerful
enough to jam or destroy electronic facilities, are reportedly also available through
catalog sales from commercial vendors.65
It is difficult to assess the threat of a terrorist organization possibly using a
smaller-scale HPM weapon against the United States critical infrastructure. It could
be argued that an HPM bomb by itself, may not be attractive to terrorists, because its
smaller explosion would not be violent enough, and the visible effect would not be
as dramatic as a larger, conventional bomb. Observers have reported that the
leadership of some terrorist organizations may increasingly become aware of the
growing advantages from an EMP attack launched against U.S. critical information
systems. In addition, the use of a new weapon directed at U.S. information systems
would attract widespread media attention, and may motivate other rival groups to
follow along a new pathway.66
Human Rights
HEMP and HPM energy weapons primarily damage electronic systems, with
little or no direct effect on humans, however, these effects may be difficult to limit
or control. As HEMP or HPM energy fields instantly spread outward, they may also
affect nearby hospital equipment or personal medical devices, such as pace-makers,
or other parts of the surrounding civilian infrastructure. For this reason, some
international human rights organizations may object to the development or testing of
HEMP or HPM weapons.
Legislative Activity
P.L. 110-181, The National Defense Authorization Act for Fiscal Year 2008,
requires the Department of Homeland Security to coordinate efforts with the
Commission for work related to electromagnetic pulse attack on electricity
infrastructure, and protection against such attack. Funding by provided by the
Department of Defense to the Commission for preparation and submission of the

63 (...continued)
Kopp, “The Electromagnetic Bomb — A Weapon of Electrical Mass Destruction,” Air and
Space Power, 1993.
64 Kenneth R. Timmerman, “U.S. Threatened with EMP Attack,” Insight on the News, May

28, 2001.

65 Personal communication with EMP Commission. Diehl BGT Defense, High Power
Microwaves, [http://www.diehl-bgt-defence.de/index.php?id=547&L=1].
66 Jerrold M. Post, Kevin G. Ruby, and Eric D. Shaw, “From Car Bombs to Logic Bombs:
The Growing Threat from Information Terrorism,” Terrorism and Political Violence, vol.

12, no. 2 (summer 2000), pp. 97-122.

final report is limited to $5,600,000. The deadline for the submission of the final
report of the Commission has been extended to November 30, 2008.
CRS Products
CRS Report RL32114. Botnets, Computer Attack, and Cyber Terrorism:
Vulnerabilities and Policy Issues for Congress.
CRS Report RL32411. Network Centric Operations: Background and Oversight
Issues for Congress.
CRS Report RS21528. Terrorist "Dirty Bombs": A Brief Primer.
CRS Report IB92099. Nuclear Weapons: Comprehensive Test Ban Treaty.