It wasn't a liquid. At least not the part sewed into his underwear.
Can full-body airport scanners harm you?
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January 4, 2010 4:28 PM PST
by Elizabeth Armstrong Moore
Since explosive materials were sneaked onto a U.S. domestic flight on Christmas Day, full-body scanning machines are far more likely to make their way to security lines at your local airport, even though they might not have detected said materials.
While the Transportation Security Administration already has 40 such devices in place, it just bought 150 to be placed in U.S. airports and says it plans to buy 300 more (they go for $170,000 apiece). On Wednesday, the Netherlands announced that these scanners would be used on passengers for all flights out of Amsterdam to the U.S., and there is talk of scanners in Nigeria as well.
So, setting aside the non-health-related question of whether the scanners will work in detecting explosive materials, are they safe?
These full-body scanners fall into two main categories: millimeter wave and backscatter. The first directs radio waves over a body and measures the energy reflected back to render a 3D image. The latter is a low-level X-ray machine that creates 2D images.
The scanners are supposed to be the high-tech (and energy-inefficient) version of a pat down, and can detect items such as nonmetallic weapons and explosives not picked up by metal detectors. (They only scan surfaces, so body cavity stashing may soon get all the more popular.)
Millimeter wave scanners produce 30 to 300 gigahertz electromagnetic waves, and reveal explosives if they are denser than other materials. This means that these scanners emit less radiation than a typical cell phone, according to TSA. Whether cell phones are harmful is of course the topic of many debates.
The backscatter machines, meanwhile, are low-level X-ray machines that expose bodies to as much radiation as about two minutes of flying in an airplane does. In other words, if you already use a cell phone and you already fly, you are already exposing your body to more radiation than these scanners will.
David Brenner, professor of radiation biophysics at Columbia University and co-author of a report on radiation scanning systems (PDF here), tells me that the risks associated with these low-level radiation scanners are extremely small.