GAO raises questions about effectiveness of full-body scanners

The foiled Christmas Day attempt by a Nigerian suicide bomber to bring down a Detroit-bound plane by hidings explosives in his underwear has given new impetus to bolstering airport security. The immediate beneficiaries are full-body scanners technologies.

Owing to privacy concerns, the U.S. Congress, only last June, overwhelmingly passed a law instructing that these scanners should be used only as secondary scanners, that is, be used on passengers which have aroused suspicion for whatever reason. The EU, on similar grounds, ruled against full-body scanners last year.

These objections were brushed aside in the post-Christmas rush to improve airport security:

• The Obama administration has unveiled a plan to deploy body-imaging scanners at most U.S. commercial airports at a cost to U.S. taxpayers of about $3 billion over eight years
• The Transportation Security Administration (TSA) is planning to deploy 450 full-body scanners at U.S. airports by the end of this year, 950 scanners by the end of 2011, and 1,800 by the end of 2014
• Airports around the world, especially those with direct flights to the United States, have been deploying full-body scanners at a fast clip

The two main concerns raised about these scanners:

• privacy, because some of the technologies used - for example, active millimeter-wave radiation — generate anatomically accurate images of passengers’ bodies
• health, because some technologies, for example, backscatter X-ray, inundate passengers with large amounts or radiation (although many physicians say the amount of radiation is not health-threatening)

Questions are now being raised about the effectiveness of these scanners. The Washington Post’s Spence Hsu reports that congressional investigators told lawmakers that it is unclear whether the controversial machines would have caught Nigerian underwear bomber. Security experts say the advanced imaging technology, or AIT, has limits: The backscatter rays can be obscured by body parts, may not readily detect thin items seen “edge-on” or objects hidden inside the body, and require a human operator to decide whether to conduct additional questioning or a physical search.

“While officials said [the scanners] performed as well as physical pat downs in operational tests, it remains unclear whether the AIT would have detected the weapon used in the December 2009 incident,” the Government Accountability Office (GAO), Congress’s audit arm, said Wednesday in written testimony to the House Homeland Security Committee.

GAO official Steve Lord told the panel that the TSA should conduct a new cost-benefit study before deploying the scanners.

Hsu writes that the audit agency said the TSA estimates that each unit costs about $170,000, meaning it would cost about $300 million to buy 1,800 units, enough to cover about 60 percent of screening checkpoint lanes at the highest-priority commercial airports. Each scanner requires three people to run it. Based on the administration’s request for $219 million to hire 3,550 TSA staffers next year, the GAO estimates it will cost $2.4 billion overall to staff the machines over eight years.

Hsu quotes TSA spokeswoman Kristin Lee to say that the agency has conducted a cost analysis and determined that scanners are better than existing alternatives, including metal detectors and machines that check swabs of people’s hands or belongings for traces of explosives. The TSA said the machines boost the odds that security officials will detect anomalies in a fraction of the time and inconvenience that pat-down searches take. “While there is no silver-bullet technology, AIT is very effective at detecting metallic and nonmetallic threats on passengers, including explosives,” the spokeswoman said in a statement.

Questions about the effectiveness of the machines have not reduced the focus on privacy and health concerns. Privacy groups say full-body scanning amounts to electronic strip searches. The Inter-Agency Committee on Radiation Safety, which includes the European Commission, the International Atomic Energy Agency, and the World Health Organization (WHO), suggested this year in an internal report that, although the radiation dose is extremely small, pregnant women and children should not undergo scanning.