CRS Report for Congress
High Altitude Electromagnetic Pulse (HEMP) and
High Power Microwave (HPM) Devices:
Updated July 21, 2008
Specialist in Technology and National Security
Foreign Affairs, Defense, and trade Division
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
1Michael Sirak, “U.S. vulnerable to EMP Attack,” Jane’s Defence Weekly, July 26, 2004,
2Report of the Commission to Assess the Threat to the United States from Electromagnetic
Pulse (EMP) Attack; Critical National Infrastructures, Apr 2008, p.vi-viii, and p.79.
To read more please visit: http://www.fas.org/sgp/crs/natsec/RL32544.pdf