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Winter/Spring 2006 Vol. 6 No. 1

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© Dynamic Graphics/Jupiterimages Protecting Air Transportation

Better Defenses Against Chemical and Biological Threats

The U.S. air transportation system is an attractive target for attacks with chemical or biological agents. Not only do the large luggage-toting crowds at airports make terrorists hard to spot, the dispersal of passengers to destinations around the world makes it much easier to spread infectious diseases or dangerous toxins widely.

A new report from the National Research Council recommends that responsibility for guarding against such an attack be assigned to the Transportation Security Administration. Defending against a chemical or biological attack means understanding the spaces likely to be targeted -- in this case, terminals, boarding areas, and aircraft -- and in particular knowing how the air-handling systems in those spaces operate. TSA is the agency with the most knowledge about the unique physical characteristics of airports, concluded the committee that wrote the report.

TSA should collaborate with other entities in the U.S. Department of Homeland Security to form a high-level task force to develop a specific defensive strategy, the committee recommended. The task force also should keep up-to-date "threat assessments" that outline scenarios of how terrorists might release agents in airports and planes, or directly into their air-handling systems. The task force should use chemical and biological simulants to explore how particles disperse, and it should take advantage of research that models airflow within aircrafts and terminals.

Some of the research and development of chemical and biological sensors is promising, but their performance is hard to evaluate, the committee said, and none of the technologies is ready to be deployed in an airport or plane. Regardless, relying solely on sensors to detect an attack would be a mistake. A vast number of dangerous chemicals and pathogens must be monitored for, and an attack with fast-acting agents would begin producing symptoms in victims in about the same amount of time it would take for a sensor to sound an alarm. In this case, video monitoring, especially coupled with behavioral-pattern-recognition software, would be the fastest way to realize an attack had occurred. Besides improved video surveillance, the committee recommended that TSA focus on protective measures such as reducing airflow between different airport areas and limiting access to air intake vents. The agency should also promote the development and deployment of "active purification units" that could reduce or eliminate infectious biological agents and some fast-acting chemicals in systems delivering air to terminals and aircraft. Establishing a separate air supply for critical areas such as control towers should be considered as well.   -- Bill Kearney

Defending the U.S. Air Transportation System Against Chemical and Biological Threats. Committee on Assessment of Security Technologies for Transportation, National Materials Advisory Board, Division on Engineering and Physical Sciences, and the Transportation Research Board (2006, 46 pp.; ISBN 0-309-10074-7; available from the National Academies Press, tel. 1-800-624-6242; $12.00 plus $4.50 shipping for single copies).

The committee is chaired by James F. O'Bryon, retired deputy assistant secretary of defense, Belair, Md. The study was funded by the Transportation Security Administration.

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Copyright 2006 by the National Academy of Sciences