A major threat to America has been largely ignored by those who
could prevent it. An electromagnetic pulse (EMP) attack could wreak
havoc on the nation's electronic systems-shutting down power grids,
sources, and supply mechanisms. An EMP attack on the United States
could irreparably cripple the country. It could simultaneously
inflict large-scale damage and critically limit our recovery
abilities. Congress and the new Administration must recognize the
significance of the EMP threat and take the necessary steps to
protect against it.
Systems Gone Haywire
An EMP is a high-intensity burst of electromagnetic energy
caused by the rapid acceleration of charged particles. In an
attack, these particles interact and send electrical systems into
chaos in three ways: First, the electromagnetic shock disrupts
electronics, such as sensors, communications systems, protective
systems, computers, and other similar devices. The second component
has a slightly smaller range and is similar in effect to lightning.
Although protective measures have long been established for
lightning strikes, the potential for damage to critical
infrastructure from this component exists because it rapidly
follows and compounds the first component. The final component
is slower than the previous two, but has a longer duration. It
is a pulse that flows through electricity transmission
lines-damaging distribution centers and fusing power lines. The
combination of the three components can easily cause
irreversible damage to many electronic systems.
An EMP attack on the United States could materialize in two
forms: nuclear and non-nuclear. The most devastating form, and most
difficult to achieve, is an EMP that results from a nuclear weapon.
This form destroys any "unhardened" electronic equipment and
electric power system- which means virtually any civilian
infrastructure in the United States. The pulse occurs when a
nuclear weapon explodes above the visual horizon line at an
altitude between 40 and 400 kilometers. The detonation of the
nuclear warhead releases photons in the form of gamma radiation and
x-rays. These energetic particles scatter in every direction away
from the blast. Many of the particles descend and interact with the
magnetic field lines of the Earth, where they become trapped. The
trapped electrons then create an oscillating electric current
within the field, which rapidly produces a large
electromagnetic field in the form of a pulse. Once the pulse
reaches electronic equipment, it negatively interacts with them and
either disables, damages, or destroys them. An EMP generated by a
nuclear weapon could affect all critical infrastructures that
depend on electricity and electronics within the vicinity of the
nuclear warhead blast radius. A nuclear weapon with a burst height
of approximately 100 kilometers could expose objects located within
an area 725 miles in diameter to the effects of EMP.
A non-nuclear, or improvised, EMP is a radio-frequency (rather
than gamma or x-ray frequency) weapon. While easier to conceal and
not requiring a missile, a non-nuclear EMP must be detonated close
to the target and does not produce as much damage as the nuclear
version, affecting largely localized areas. But such a
weapon could be harnessed as an "E-Bomb" (electromagnetic bomb), a
stand-alone weapon that is easier to hide and maneuver. It is
difficult to estimate the exact damage of an improvised
attack, but in 1993 EMP testing by the U.S. military shut down
engine controls 300 meters away at a contractor site.
Not large-scale by any means, but damaging enough to cause
It was not until the United States began high-altitude
testing of nuclear weapons over the Pacific in the early 1960s that
the potentially devastating effects of EMP on even distant ground
targets attracted widespread attention within the U.S. defense
community. In the 1962 Starfish Prime test, during which a nuclear
weapon was detonated 400 kilometers (250 miles) above Johnston
Island in the Pacific, electrical equipment more than 1,400
kilometers (870 miles) away in Hawaii was affected. Street
lights, alarms, circuit breakers, and communications equipment
all showed signs of distortions and damage.
In 1997 and 1999, the House National Security Committee and the
House Military Research and Development Subcommittee held hearings
on the potential threats to civilian systems in America from an EMP
attack. Congress subsequently established the Commission to Assess
the Threat to the United States from an Electromagnetic Pulse (EMP)
Attack, also known as the Graham Commission after its chairman,
William Graham (former science advisor to President Ronald Reagan).
The Commission issued a report in 2004 that evaluated the threat to
the U.S. from an EMP attack, assessed vulnerabilities in both
military and civilian systems, and offered recommendations for
overcoming these weaknesses. The Commission recommended
hardening key power nodes as well as storing spares of
essential but hard-to-build components of the U.S. electric grid
and other critical infrastructure for communications, finance, and
emergency public services. Congress held hearings the same year
to evaluate the Commission's recommendations, but little tangible
progress followed. The Commission was re-established in
2006 to continue monitoring the EMP threat.
A few select sites have been hardened against an EMP attack
since the threat was identified. Air Force One, the airplane that
carries the U.S. President, is designed to withstand an EMP attack.
During the Cold War, the U.S. military hardened its most important
military systems, such as U.S. nuclear weapons systems, against EMP
threats. These efforts have decreased since the end of the Cold
War, despite the continued vulnerability of these systems.
Presently, most efforts to counter the EMP threat are focused on
initiatives to stop the proliferation of nuclear weapons and
ballistic missiles. These efforts include programs like the
Proliferation Security Initiative, the Cooperative Threat
Reduction Program, and the Global Initiative to Combat Nuclear
Comprehensive threat assessment and scenario planning for EMP
attacks remain underdeveloped. This inaction is in the face of
warnings, such as the one in the 2006 Quadrennial Defense
Review(QDR)which stated clearly that the "expanded reliance on
sophisticated electronic technologies by the United States, its
allies and partners increases their vulnerability to the
destructive effects of electromagnetic pulse (EMP)."
Yet, the Department of Defense has not implemented the QDR's
proposed EMP Action Plan. Meanwhile, the Department of Homeland
Security (DHS) has focused on other urgent threats, such as from
conventional explosive devices or chlorine bombs, concluding that
EMP is simply not a large enough threat for its attention. Even the
National Infrastructure Protection Plan (NIPP), the plan dedicated
to ensuring that U.S. critical infrastructure is protected from
terrorist attack, does not directly address the EMP threat.
Congress has recently reassumed its leadership role on EMP by
holding hearings on the issue in July 2008, but its ability to
compel executive branch action in this area is limited.
While many non-federal homeland security authorities in many
U.S. states express concern about an EMP attack, a comprehensive
survey found that state-based emergency responders and National
Guard units have done little to prepare for such an incident. Alaska, perhaps because of its
relative isolation from most federal emergency response assets and
the state's vulnerability due to its reliance on satellite-based
communications, is a notable exception. In May 2007, the Alaskan
state government announced it would include EMP when it next
revises its emergency response plan. The state's homeland security
officials plan to address the vulnerability of the state's
electric and telecommunications infrastructures as well as
related integration, implementation, and survivability issues. Alaska's efforts are considerable
in comparison to other states; most have not even touched the
issue. Limited state preparedness for an EMP attack is
especially dangerous given the inability of the U.S.
government, itself mostly unprepared for an EMP strike, to render
much if any immediate assistance.
Americans remain gravely ill prepared for an EMP attack. In
fact, the average U.S. city has only three days worth of food and
health care provisions. Most Americans do
not have enough batteries to keep flashlights working for any
period of time, much less generator capabilities. And many of the
country's most vulnerable citizens rely on the electricity grid for
medical equipment, such as dialysis machines. Even standard
medication will be difficult or impossible to come by if EMP
disables pharmacies and transportation networks.
A Weapon of Mass Disruption
EMP has been dubbed a "weapon of mass disruption" because
of its ability to devastate its target by disrupting electronic
infrastructure. The August 2003 Northeast Blackout that affected
Ohio, New York, Maryland, Pennsylvania, Michigan, and parts of
Canada demonstrated the potential effects of a wide-area EMP
attack. During that incident, more than 200 power plants, including
several nuclear plants, were shut down as a result of the
electricity cutoff. Loss of water pressure led local authorities to
advise affected communities to boil water before drinking due to
contamination from the failure of sewage systems. Many backup
generators proved unable to manage the crisis.
The day of the blackout brought massive traffic jams and
gridlock when people tried to drive home without the aid of traffic
lights. Additional transportation problems arose when
railways, airlines, gas stations, and oil refineries also halted
operations. Phone lines were overwhelmed due to the high
volume of calls, while many radio and television stations
went off the air. Overall, the blackout-which lasted only one
day-cost $7 billion to $10 billion in spoiled food, lost
production, overtime wages, and other related expenses inflicted on
more than one-seventh of the U.S. population.
In the case of an EMP attack, depending on whether it is nuclear
or improvised, the damage could easily prove more severe. An EMP
detonation could affect car and truck engines, aircraft ignition
systems, hospital equipment, pacemakers, communications
systems, and electrical appliances. Road and rail signaling,
industrial control applications, and other electronic systems are
all susceptible to EMP. Electromagnetic energy on a radio frequency
will travel through any conductive matter with which it comes into
contact-from electrical wires to telephone wires, even water
mains-which can spread the effects to areas far beyond ground
A successful EMP attack could result in airplanes literally
falling from the sky; vehicles could stop functioning, and water,
sewer, and electrical networks could all fail-all at once. Food would rot, health care would
be reduced to its most rudimentary level, and there would not
be any transportation. Rule of law would become impossible to
sustain; police departments would be overwhelmed.
Communication abilities would be limited, preventing
federal, state, and local governments from communicating with one
another-severely limiting abilities to shift needed resources
around the country. During the 2003 blackout, some
communications systems remained intact. Cars and aircraft were
not directly affected and rapidly resumed operation after the
electrical system recovered a few days later. In an EMP attack,
however, the damage to power lines, supervisory control and data
acquisition (SCADA) control systems (for utility systems
infrastructure), and commercial computers would very likely be
permanent due to fused power lines and lost data-which would
require replacing the entire electric system in the affected area.
One estimate warns that the likely costs from the detonation
of an EMP weapon over the Washington, D.C., metropolitan area
could exceed $770 billion. Millions of Americans could suffer
death or injury, and social chaos could ensue.
Besides the domestic consequences of an EMP attack, it would
also be difficult for the U.S. to organize a coherent
retaliatory strike against the aggressor. America's armed
forces may simply be unprepared for an attack, or our national
devastation could prove too distracting. Furthermore, it may
be too difficult to rapidly determine the perpetrator of the
attack, for instance, if a compact E-Bomb were smuggled into the
U.S. If a nuclear warhead is detonated in orbit, there is a strong
potential for substantial damage to U.S. and other satellites as
well as any spacecraft in use at the time of the explosion. The
military applications of such satellites are critical for defense
systems that rely on GPS guidance, such as ballistic missiles and
many conventional military strike weapons. The adverse impact on
U.S. space-based communications, early-warning assets, fire-control
systems, overhead sensors and imagery, and geospatial
intelligence would be substantial as well.
Near-term recovery could prove impossible because of America's
dependence on extensive transportation networks and other
electricity-powered infrastructures. America's infrastructure
is highly interconnected, as was demonstrated during the blackout.
A problem in one part of the country can translate into problems
across the United States, contributing immensely to lives lost and
property destroyed during an EMP attack.
Potential U.S. Adversaries Have the
Knowledge-and the Capability
The range of actors that might attempt an EMP attack against the
United States is obviously-and distressingly-large and includes
conventional military regimes, rogue states with limited
conventional military capabilities, and terrorist groups that
seek to inflict catastrophic damage on America. Both Russia and
China have dabbled in EMP technology for decades.
There is evidence that suggests that certain Russian
nuclear weapons have already been optimized to generate enhanced
EMP effects. Just this year, Russian scientists
claimed to have developed a compact apparatus that can fit on
a dining table. The electromagnetic pulse associated with this
device could amount to billions of watts of power in a single
platform. Analysts have also identified
Chinese military writings that discuss using EMP weapons in
For countries less dependent on modern technologies and
electronics, including both rogue states like Iran and North Korea
as well as stateless terrorist groups, EMP provides a potential way
to attack the United States through asymmetric means. EMPs could be
used to circumvent America's superior conventional military
power while reducing vulnerability to retaliation in kind. It
would certainly not be impossible for a terrorist organization,
especially if state-sponsored, to acquire or construct an
unsophisticated ballistic missile (non-working Scuds are
reportedly available on the open market for $100,000) and use it in
an EMP attack against America. Such a missile could
be launched from a freighter in international waters and detonated
in the atmosphere over the United States without warning.
The materials used to build non-nuclear EMP weapons can be
easily acquired or manufactured by moderately developed terrorist
groups with even limited financial resources. Although the
potential impact is less, an improvised EMP could still inflict
major damage. The construction of a nuclear weapon is much more
difficult and requires a good understanding of physics, electrical
engineering, and explosives; but these terror groups are actively
seeking to gain this knowledge, and rogue states could see
opportunity in collaborating with these groups to accelerate the
The Time for Action Is Now
The U.S. cannot continue to ignore the EMP threat. While some
progress has been made in hardening potential U.S. targets
against attack, including critical military and government systems,
the vast majority of electrical systems are unshielded and
unprotected, especially in the civilian sector. If properly
shielded, electrical devices and systems can generally survive even
the strongest EMPs. Congress and the new Administration
- Perform More Research on the Threat. Further research is
needed in order to ensure that America can respond to the EMP
threat appropriately without wasting government resources on flimsy
or useless security measures. Although there are numerous methods
to harness EMPs capable of affecting electronic systems, there is
still a theoretical limit to what damage they can produce in
terms of both geographic size and intensity.
Some EMP weapons release just enough energy to disable small
electrical devices while others can destroy all the electronic
devices and systems within a city block. Altitude plays a
major role in whether an EMP attack will be successful; lower
heights typically expose a smaller surface area to EMP damage. Some
systems are simply more vulnerable to EMP attack than others, such
as devices plugged into power grids and commercial computer
equipment. The U.S. government must gain knowledge of the
attributes and capabilities of EMP and understand the amount of
money, time, and effort that will be required for meaningful
prevention. EMP research should also include actions by
Congress to simulate the effects of an EMP attack on
Washington and other high-value targets and re-examine the Graham
- Build a Comprehensive Missile Defense System. The
most likely method of EMP attack would be a ballistic missile armed
with a nuclear warhead. Building a comprehensive missile defense
system would allow the U.S. to intercept and destroy a missile
bound for the United States. The mere implementation of such a
system would go a long way to prevent an attack by dissuading
those who wish to carry out such actions and sending a clear
message that the U.S. takes this threat seriously.
Those opposed to missile defense in Congress and elsewhere have
attempted to paint such an endeavor as a waste of resources that
does nothing to further American security. 33 Minutes:
Protecting America in the New Missile Age, A Reader, a
collection of essays by pre-eminent defense scholars, emphasized
the need for such measures, and recent missile testing by Iran
demonstrates that other countries are actively involved in
developing missile programs-which could be used against the U.S.
- Incorporate EMP Attacks into National Planning
Scenarios. The National Planning Scenarios are 15
all-hazards planning scenarios used by federal, state, and local
officials in disaster response exercises. The exercises can
determine capabilities and needs and address problems before a
disaster instead of after the fact. Given an EMP attack's unique
nature and its ability to paralyze the U.S., individualized
preparation is necessary. EMP must be added to the list.
- Develop a National Recovery Plan. The U.S. must identify
the key power grid and telecommunications infrastructure that
is critical to preserving our nation's core capabilities
and create a National Recovery Plan. This risk-based approach
recognizes that certain infrastructure is key to recovery after an
EMP attack. By taking measures to protect this infrastructure, we
can lessen the recovery time from an attack.
According to the National Fire Protection Association's
(NFPA) "Standard on Disaster/Emergency Management and Business
Continuity Programs," a private company should prepare to function
without electricity for a short period in order to maintain
uninterrupted operations. While this time period will
certainly vary by industry, encouraging the private sector to
prepare in this manner and to develop company recovery plans will
allow the government to focus on bringing key infrastructure back
online. The private sector can move toward this goal by investing
in more adequate infrastructure now.
A Threat too Big to Be Ignored
Although many in Congress and the White House tend to ignore the
EMP threat, America's potential adversaries will not. To these
adversaries, EMP technology represents the opportunity to
inflict-with relative ease-catastrophic and lasting damage on the
United States that could threaten our very existence. Preventing
such an attack depends on the U.S. government's ability to
understand the very real chance and the devastating consequences of
an EMP attack-and to take the actions necessary to prevent
Jena Baker McNeill is
Policy Analyst for Homeland Security in the Douglas and Sarah
Allison Center for Foreign Policy Studies, a division of the
Kathryn and Shelby Cullom Davis Institute for International
Studies, at The Heritage Foundation and Richard Weitz, Ph.D., is
Senior Fellow and Director of Program Management at the Hudson
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"Report of the Commission to Assess the Threat to the United States
from Electromagnetic Pulse (EMP) Attack," The Graham Commission,
Vol. 1 (2004), p. 3, at /static/reportimages/5B674F4CD79EB25147C3B5F295C66BD4.pdf
(September 13, 2008).
Independent Working Group on Missile
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(October 9, 2008).
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 Foster, Jr., et al., "Report of
the Commission to Assess the Threat to the United States from
Electromagnetic Pulse (EMP) Attack," pp. 17-23.
 Clay Wilson, "High Altitude
Electromagnetic Pulse (HEMP) and High Power Microwave (HPM)
Devices: Threat Assessments," Congressional Research Service
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(July 3, 2008).
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(October 8, 2008).
 Wilson, "High Altitude Electromagnetic
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 Institute of the North and The
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of the States," 2007, at http://www.missilethreat.com/repository/docLib/20070306
_MissileDefenseandtheStates.pdf (June 30, 2008).
 Press Release, "Alaska to Revise
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 CNN, "Major Power Outage Hits New York,
Other Large Cities," August 14, 2003, at http://www.cnn.com/2003/US/08/14/power.outage
(October 8, 2008). See also The Electricity Consumers Resource
Council, "The Economic Impacts of the August 2003 Blackout,"
February 9, 2004, pp. 1-3, at http://www.elcon.org/Documents/EconomicImpactsOfAugust2003Blackout.pdf (October 8, 2008).
 Marshall A. Hanson, "Ultimate Weapon: A
High-Energy Electromagnetic Pulse Could Cause Mass Destruction to
America's Infrastructure," The Officer, November 1, 2006, p.
 James G. Zumwalt, "Not a Movie Made for
T.V." The Washington Times, October 2, 2007, p. A16.
 Schneider, The Emerging EMP Threat
to the United States, pp. 6-9.
 United States Army, "Electromagnetic
Pulse (EMP) Protection," Grounding and Bonding in Command, Control,
Communications, Computer, Intelligence, Surveillance, and
Reconnaissance (C4ISR) Facilities TM 5-690, February 15, 2002, at
http://www.usace.army.mil/publications/armytm/tm5-690/c-5.pdf (October 8, 2008).
33 Minutes: Protecting America in
the New Missile Age, A Reader (Washington, D.C.: The Heritage
Foundation, 2008), forthcoming.