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Liberty RadEx Drill Helps Nation Prepare for ‘Dirty Bomb’ Scenario

EPA scientists helped plan and support major simulation of testing, clean up, and recovery phases following a deliberate radiation attack.

EPA emergency response vehicle

On the night of May 1, 2010, a crude car bomb rigged from gasoline, firecrackers, and alarm clocks was discovered smoldering in the heart of New York City’s Times Square. Fortunately, the bomb never exploded. Instead of mass casualties, the failed terrorist attack provided another chilling example of the critical need for continued vigilance in homeland security activities.

Not more than three weeks before the failed car bomb, experts from the U.S. Environmental Protection Agency (EPA) led an extensive training exercise for responding to a terrorist attack. Officials from a host of different government agencies and private companies prepared for the detonation of a “dirty bomb” containing radiological materials. Such an event would lead to widespread contamination, disruption, and fear.

Sponsored and designed by EPA, “The National Tier 2 Full-Scale Radiological Dispersion Devise Exercise”—named Liberty RadEx (PDF) (14 pp, 1.1 MB)— was a national drill to practice and test federal, state, and local assessment and clean up capabilities in the aftermath of a dirty bomb, “a radiological dispersion device incident,” in an urban environment.

Various Presidential Directives following the terrorist attacks of September 11, 2001 and the subsequent issuance of the National Response Framework confirmed EPA’s historic and regulatory role as the federal agency responsible for leading the assessment, mitigation, and cleanup of hazardous materials, including weapons of mass destruction, following a terrorist attack.

The Agency established a homeland security research program to develop and deliver reliable, responsive expertise and products based on scientific research and technology evaluations for hazardous materials and for EPA’s drinking water protection responsibilities.

EPA scientists and engineers were intimately involved in the planning and execution of the Liberty RadEx drill to ensure that the latest research and technology would be available to all participants. For more than a year, EPA researchers participated in multi-agency workgroups to help define the critical, long term issues that would have to be addressed during the aftermath of a dirty bomb explosion.

“In the aftermath of a dirty bomb attack, it is critically important for local officials and communities to have access to the best available science and expertise,” explains Bill Steuteville, EPA Region 3 Homeland Security Coordinator and one of the Exercise Directors for Liberty RadEx. “EPA has such expertise and capabilities and is one of the lead federal agencies working on homeland security research.  Liberty RadEx was a great opportunity to work with our state and local partners to demonstrate EPA’s capabilities and the latest detection and clean-up technologies in order to protect the public and help the community efficiently and effectively.”

The scenario in the Liberty RadEx exercise was built around the likely aftermath of a suicide attack launched from a van loaded with 3,000 pounds of ammonium nitrate mixed with diesel fuel and radioactive Cesium-137.

EPA emlpoyee putting on a protective suit

EPA’s Emily Snyder suits up for Liberty RadEx exercises.

More than 1,000 participants, representing federal, state, and local agencies, as well as private citizens and companies, were involved. Field drills and training exercises took place April 27 to 29, 2010 in and around Philadelphia, PA.

During the Liberty RadEx exercise, EPA scientists and engineers served as “controllers,” providing expertise and technical support.  They also helped challenge participants by adding scientifically-based complexities known as “injects” (such as sudden changes in the situation or the discovery of new information) to the simulations and exercises, creating better learning experiences based on the risks and challenges that might unfold during a real radiological event.


The drill provided a real-world opportunity to apply and demonstrate clean-up technologies that had previously been tested primarily in EPA’s research laboratories. During the drill, participants were able to apply one such technology, Stripable Coatings for Radioactively Contaminated Surfaces, in both a subway station and the Philadelphia Fire Department Training Academy’s building.

EPA researchers and their partners used Liberty RadEx events to further develop and test a new tool that superimposes contaminant plume maps over Geographical Information System data to estimate the quantities and activity levels of contaminated waste and debris, including buildings, asphalt, and soil. Officials in charge of clean-up and decontamination activities applied these estimates to evaluate trade-offs between decontamination and disposal.

While most training exercises to date have focused on crisis response in the immediate aftermath of a terrorist attack, EPA researchers helped design Liberty RadEx to provide the first major exercise for developing and practicing the critical steps that must take place in the days and weeks after the initial response.

“This exercise was significant because it will help inform how all levels of government, business and community organizations can work together to meet challenges associated with long-term cleanup and community recovery from a dirty bomb attack,” said EPA Regional Administrator Shawn M. Garvin.

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