New Study – TSA Xray Scanners are Safe. Or Maybe Not.

A new study has been released by Marquette University, claiming the TSA X-ray whole body scanners are safe.  Bravo.  We can all now relax, right?

Well, maybe yes.  But, equally likely, maybe no.  In fact, some of us might feel that this study – rather than supporting its claim that X-ray scanners are safe – actually goes a long way towards showing quite the opposite.

The study suggested that the radiation from the scanners, which is supposed to only penetrate the smallest amount of skin, would actually penetrate into 29 different organs, including the brain and heart.  This is not what the TSA has told us, although, as you’ll read below, it is far from clear how the study authors managed to determine this.

And while the study suggests the level of radiation is ‘safe’ and lower than what you’d get from eg a mammogram, the study also suggests that the level of radiation is one third that of the maximum recommended, which is a great deal higher than has been previously claimed by the TSA.

Now think about this.  How many times a year do you get a mammogram (in the case of most men, never!).  But how many times a year might a frequent flier be irradiated at an airport?

When you keep in mind that radiation is cumulative – which sort of means that if you have 21 doses of radiation through the TSA X-ray machines during the course of a year, you’ve ended up with the equivalent of seven times the maximum suggested dose (as per ANSI).

Safe?  As women know, mammograms are infrequently given and not without some controversy.  Indeed, the National Cancer Institute, while pointing out that in the case of mammograms, the benefits probably outweigh the risks, also says

The risk of harm from this radiation exposure is low, but repeated x-rays have the potential to cause cancer.

We’re being asked to submit to something not very much less than a mammogram, and which cumulatively over multiple exposures during multiple journeys over a year comes to many times the recommended maximum.  What are the benefits that this greatly increased risk justifies?

This is an easy answer when considering mammograms, but when it comes to TSA X-ray machines, the answer is much less clear, because – as has now been repeatedly demonstrated – they just plain don’t work when it comes to detecting ‘artfully concealed’ contraband objects.  Even the TSA’s own testing has proven this – see this story about an agent who repeatedly smuggled a gun through.  And then there is the famous case where a college student worked out a loophole and posted his successful smuggling on a Youtube video.

So why is the typical frequent flier being asked to accept the equivalent of many mammograms a year, but with no balancing benefit?

The study concludes the machines are ‘safe’, but I wonder if the author ever thought beyond the issue of one single dose, and considered instead the cumulative impacts of a dozen, or two dozen, doses over each year.

One more thing.  This study was not based on any real world testing.  It was conducted as a mathematical model based on, ahem, nothing more than public data that has been previously provided by the TSA to support their unproven statements about the safety of the machines they use.  Is it any surprise that using the TSA’s own unverified data resulted in a dubious finding of possible safety?

A more rigorous study would start off with measuring the actual radiation emitted from these machines, and doing things also like testing the variation in radiation emitted from machine to machine, and within each machine, and looking for any ‘hot spots’ where radiation levels might be greater or lesser than other areas.

One of the two authors even conceded that the data the study was based on is imperfect when she said

Access to the machines for measurements and assessments is limited.  Public disclosure of the systems specifications would enable more accurate system modeling.

Here’s an unfortunately uncritical review of the findings of this study.

So, what can we conclude?  If we accept the TSA’s information without any verification or validation, and if the machine is working as it should, then a single dose of X-rays from one of the whole body scanners might be acceptable.

But, if the TSA data is, shall we say, incomplete, and/or if you expect to be radiated multiple times each year, well, you’re on your own.

This ‘study’ does nothing whatsoever to advance the overall independent understanding of the risks inherent in these machines.

And who cares if the machines are safe or not.  The fact inescapably remains that safe or not, they are also useless and ineffective in finding hidden objects artfully concealed on people going through them.  So while a debate on the safety of the machines is important, surely the more pressing matter is they just don’t work.