Is it time to retire TSA's full body scanners?

TSA relies on its L3 ProVision full body scanners, which use millimeter wave (MMW), terahertz radio frequency technology to detect objects concealed by air travelers at TSA security checkpoints.
These scanners are in use at major and midsized US airports, scanning travelers from head to foot looking for weapons, explosives and other prohibited items. It’s time to ask if these scanners have outlived any usefulness they might have had.
The question I’m asked most frequently about the MMW scanners is how much do they cost. According to the GSA (General Services Administration), the three models of the L3 ProVision Whole Body Scanners TSA is using at their airport checkpoints cost $141,000 each. Top quality “walk through” metal detectors used in the TSA Precheck line cost about $4,000, less than 3 percent of the full body scanner.
I’m also asked if the MMW scanners are really x-ray-free and safe for air travelers. They are x-ray-free. In fact, the MMW full body scanners emit no ionizing radiation whatsoever.
Whether the MMW-based scanners are safe, as claimed by their manufacturer L3, as well as TSA, in my opinion, is unknown. I can find no evidence whatsoever that a long term safety study of the MMW scanners, conducted by an independent panel of scientists and physicians, has ever been conducted.
There is some evidence that terahertz radiation can be unsafe, but test results are mixed. Boian Alexandrov, about whom I’ve written before, with the help of colleagues at the Center for Nonlinear Studies at the Los Alamos National Laboratory in New Mexico, did some work on the effects of terahertz radiation and reported significant genetic damage was possible. Elsewhere, some scientists have reported no damage.
The MIT Technology Review reports that Alexandrov created a model to investigate how terahertz radiation interacts with DNA. Alexandrov and colleagues reported that while the forces involved are tiny, their effects allow terahertz waves to “unzip double-stranded DNA, creating bubbles in the double strand that could significantly interfere with processes such as gene expression and DNA replication.”
We know that terahertz waves are part of our environment, but now TSA is using full body scanners which barrage air travelers in the scanner booths with this kind of wave. That there is a chance these machines can damage human DNA and that no long term independent tests have been made is very scary to me.
Travelers want to know if the MMW scanners actually work. From what I’ve seen, they’ll catch travelers secreting most guns, knives, and martial arts stars, all which metal detectors will also find. They may or may not detect a home-made plastic gun, printed on a 3D printer, or a ceramic based gun. They may or may not detect explosives taped to an air traveler’s body, and it’s virtually impossible for them to detect an explosive secreted in a body cavity, since MMW waves can’t penetrate the skin.
Umar Farouk Abdulmutallab, the underwear bomber, concealed a package of the chemical powder explosive PETN. Tests conducted by scientists at the British security company Qinetiq showed MMW scanners were unlikely to have picked up the PETN in Abdulmutallab’s underwear. That finding was confirmed by the GAO (Government Accountability Office), which said in part about the incident, “…it remains unclear whether the AIT would have detected the weapon…”
The problem is these scanners can’t find items which have low densities, such as PETN explosive powder, many liquids or thin plastics because the terahertz waves pass right through them as they have a density similar to clothing, rendering them invisible to the scanner. The scanners’ inability to scan body cavities also means a dedicated terrorist could easily secret higher density explosives there and know the scanner won’t pick it up.
MMW scanners apparently have a high rate of false positives, sending innocent travelers to humiliating and dehumanizing enhanced patdowns which would be called sexual assault anywhere else. Tests in Europe have shown false positives from these units as high as 50 percent.
The frequency of false positives can and has been reduced to make the units useable, but it’s at the expense of efficacy and by requiring travelers to remove all but their underwear and last layer of clothing, belt and shoes. Plus, every time a false positive occurs the screening process slows down. MMW scanners have never sped up the security lines, as promised, in large part due to false positives. Airport security lines remain far too time consuming.
Should TSA retire their full body scanners? I think the verdict is a resounding yes!
The MMW-based full body scanners are expensive and may be unsafe. The scanners have never achieved their goal of dramatically speeding security lines because of their false positives. Dedicated terrorists can beat the scanner.
There is no point in using these MMW scanners. They need to be retired now!