The first issue is the price.  According to reports, current T-Wave (Terahertz-Wave) full-body scanners cost around $166K USD each.  The Transportation Safety Administration has thus far been averaging about 2 scanners per airport.  That could put the cost of President Obama's proposed full scale deployment at around $100M USD to cover all of the approximately 600 airports certified for large commercial aircraft (and as much as $3.2B USD to put a single scanner at all airports, including smaller private ones, in the U.S.).

Would that investment be worth it?  Recent studies by the British government revealed that the current generation of full-body scanners are unable to detect lightweight materials like plastics, chemicals, or liquids.  Bags of substances like the chemicals smuggled in the failed Christmas Day attack would likely slip through, as the scanners are unable to detect them.

The TSA claims that the health risk from the high-frequency scans is very low.  However, in population groups with certain mutations that make them sensitive to radiation (typically due to lacking DNA repair mechanisms), this risk could become very serious, though.  Furthermore, recent studies have revealed that this type of scan can cause mild DNA damage -- raising cancer concerns.

And then there's the mountain of privacy issues.  Past reports have shown that the scanners do have fully naked images, generated by the hardware and momentarily stored as raw images, which then undergo processing to obscure breasts and genitalia.  In theory, these images could be extracted, according to security experts.

Well, at least the scanners can't send or store images, said advocates.  However, that turns out to be a false claim as well.  The Electronic Privacy Information Center (EPIC) has received 2008 documents from the TSA which not only clearly state that the scanners could have such abilities, but they say that the scanners must have them.

The TSA documents state that all scanners need to be capable of storing and sending user images when in "test mode".  Those documents, obtained by a Freedom of Information Act request, catch the TSA in an apparent lie.  It's website claims, "The machines have zero storage capability."

A video on the site adds, "the system has no way to save, transmit or print the image."

A TSA official speaking on condition of anonymity claims that "strong privacy protections [are] in place", adding, "There is no way for someone in the airport environment to put the machine into the test mode."

EPIC Executive Director Marc Rotenberg points out that those claims could suggest any number of hardware or software protections.  About the only way passengers would truly be protected would be if the TSA was removing non-replaceable hardware (such as PCBs) during device deployment.  Mr. Rotenberg suggests that TSA insiders or hackers could overcome more mild obstacles, such as removed storage or software protections.

Mr. Rotenberg concludes, "I don't think the TSA has been forthcoming with the American public about the true capability of these devices.  They've done a bunch of very slick promotions where they show people -- including journalists -- going through the devices. And then they reassure people, based on the images that have been produced, that there's not any privacy concerns.  But if you look at the actual technical specifications and you read the vendor contracts, you come to understand that these machines are capable of doing far more than the TSA has let on."

The TSA official, speaking anonymously, claims the devices cannot be connected to a network.  However, given the fact that past claims were disproven, one can only wonder if that's really the whole truth.

Amid this mountain of concerns, many critics are calling for the President and the TSA to reevaluate the costly program that may endanger both the health and privacy of U.S. travelers.