Graham Allison, a Harvard University political scientist and author of a best-selling book on nuclear terrorism, said that a nuclear device is more likely to arrive in a shipping container than on a missile. But he acknowledged that preventing such an attack is expensive and that there is no guarantee prevention measures will work.
“The game between hiders and seekers is dynamic, and there is no 100 percent solution,” Allison said in an e-mail interview. “The cost-benefit trade-off is the toughest issue.”
Markey and some counterterrorism experts say that the costs of checking every U.S.-bound container could be substantially lower than the DHS estimate and that the necessary measures could be easier to implement than the agency has suggested. Research by scholars at the University of Pennsylvania’s Wharton School indicate that 100 percent of containers could be screened much more inexpensively with existing methods. A number of companies also are developing cheaper new screening technology.
Peter Boogaard, a DHS spokesman, said the department is committed to using a variety of measures, including screening, scanning and working with foreign authorities, to ensure that all goods are secure.
Pilot programs established to scan all containers were abandoned in 2009 after the agency said costs were too high and the effort led to cargo delays and logistical problems.
The current screening system relies heavily on the Customs and Border Protection agency and focuses on a small percentage of goods identified as high-risk through intelligence and analytical software. The program operates at 58 overseas ports that account for 80 percent of the cargo shipped to the United States.
“Our layered and risk-based approach provides that, at a minimum, 100 percent of high risk containers are examined through a number of measures, including screening, scanning, physical inspection, or resolution by foreign authorities,” Napolitano told Congress in her May 2 letter invoking the two-year exemption.
Kevin McAleenan, a senior CBP official, told Congress this year that the program led to inspections of 45,500 suspect containers overseas in 2011 — roughly two containers a day at each of the 58 ports in the program.
Stephen Flynn, a terrorism expert at Northeastern University and a former Coast Guard commander who has studied container security, said, “The current system is woefully inadequate for stopping any determined adversary who wants to get a weapon of mass destruction into the United States.”