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TSA Releases Radiation Testing Reports

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Saturday, March 12, 2011
radiation symbol

TSA’s mission of keeping the traveling public safe is carried out at more than 450 airports across the U.S. and its territories. A large part of keeping the public safe includes using the best technology available. Some of the screening technologies use X-ray technology, such as backscatter imaging technology, multi-view advanced technology X-rays, explosive detection systems, and single projection X-ray systems to screen baggage. TSA has implemented stringent safety protocols to ensure the technology used at airports is safe.

While these machines improve our ability to stay ahead of threats to aviation security, it’s also important that we’re doing everything we can to ensure our technology is safe for passengers and our officers.

How do we do this? Well, in addition to radiation testing of the machine before it leaves the factory, and again once it is installed at an airport, TSA requires manufacturers and/or third party maintenance providers to test each machine routinely to make sure the radiation emitted falls within applicable standards. Additionally, radiation tests are performed after any maintenance that could impact the X-ray emissions and if the unit is ever relocated from its initial installation position.

By conducting ongoing radiation tests throughout the life of the technology, TSA is going above and beyond regulatory standards to ensure passengers and operators are not being exposed to excessive radiation doses.

To increase our transparency - and to let you see for yourself that the technology is safe - we will be posting all future radiation reports online. You can see where they’ll be posted here.

As we prepared to take this step, and to verify our safety procedures, TSA recently selected 15 airports of varying sizes and reviewed reports generated from testing X-ray technologies at these airports over the last two years. You can also find all of those reports here.

The reports confirm that each piece of technology included in the review operated well-within applicable the national safety standards.

TSA did not alter or edit the reports. Names were redacted to protect privacy and several pages were incorrectly marked as SSI, but other than that, the reports are there, warts and all.

Warts? Well, while looking over these reports, we found some inaccuracies in contractor reporting that affected the documentation of some of the test results.

  • Lack of notation for the latest calibration date for the machine being tested or the most recent calibration date noted had expired on survey meters
  • Information missing regarding warning labels and other required labels on machines
  • Calculation errors not impacting safety
  • Missing survey point readings (e.g., If the test procedure required 13 points around the machine to be tested, in some cases, readings for only 11 points were reported)
  • Inconsistent responses to survey questions
  • No reading of background radiation noted
  • Missing other non-measurement related information

While these inaccuracies didn’t impact the overall assessment that the technology is safe, they are still unacceptable. We took immediate steps to hold contractors accountable and fix the mistakes, and are taking additional measures to build on the robust safety protocols currently in place, by:

  • Requiring re-testing of all backscatter advanced imaging technology units in airports, as well as all technology with inaccurate reports, by the end of March 2011;
  • Requiring contractors to re-train personnel involved in conducting and overseeing the radiation survey process;
  • Requesting the National Institute for Occupational Safety and Health (NIOSH) re-evaluate TSA’s safety program and update its 2008 report;
  • Expanding an existing partnership with the U.S. Army Public Health Command to conduct additional independent radiation surveys and radiation safety compliance audits at airports equipped with X-ray based technologies;
  • Increasing TSA oversight on the overall radiation survey and documentation process; and
  • Ensuring all appropriate contractual remedies are considered and implemented, as necessary, in the event that radiation inspections are incomplete or delinquent.
  • Also, every machine using X-ray technology that is deployed in an airport will have a new radiation test conducted within the next 12 months.
  • Administrator Pistole has also directed TSA to commission an independent entity to evaluate these protocols.
  • To provide additional transparency, TSA is posting all reports currently being conducted - and, as I said above, all future radiation reports - at as they’re completed.

To put things in perspective, here are some sources of radiation you may not have been aware of:

  • One year of naturally occurring background radiation: 300 millirem
  • Annual recommended limit to the public of radiation from man-made sources: 100 millirem
  • Chest X-ray: 10 millirem
  • Flight from New York to Los Angeles: 4 millirem
  • One day of natural background: 0.1 approximately 1 millirem (corrected 3/16/11 20:56)
  • Drinking three glasses of water a day for a year: 0.045 millirem
  • One backscatter X-ray scan: Approximately 0.005 millirem

Source: Radiation dose comparisons from the Health Physics Society and other safety experts.

Bob Burns
TSA Blog Team

If you’d like to comment on an unrelated topic you can do so in our Off Topic Comments post. You can also view our blog post archives or search our blog to find a related topic to comment in. If you have a travel related issue or question that needs an immediate answer, you can contact a Customer Support Manager at the airport you traveled, or will be traveling through by using Talk to TSA.


Submitted by Geoff on

I'm confused (or maybe you're confused). You write:

One year of naturally occurring background radiation: 300 millirem
One day of natural background: 0.1 millirem

One of these numbers must be wrong. Basic arithmetic.

Submitted by Anonymous on

"By conducting ongoing radiation tests throughout the life of the technology, TSA is going above and beyond regulatory standards to ensure passengers and operators are not being exposed to excessive radiation doses. "

Nonsense. No TSO wears a dosimetry badge.

Submitted by Concerned Observer on

It is good to know where the numbers, etc. will be posted when ready.
However, I do have a serious question. A... concern, if you may. I have heard that some of the machines appear in the first set of information to be emitting 10x the amount that the TSA states is the norm. Is this true and have/were those specific machines (been) shut down, until those numbers were retested?

Submitted by Mike on

I really wish that while laying out the different dosages you would also mention that because of the energy level of the back scatter machine all of the dose is deposited in the skin and eyes.

Leaving that out is a lie by omission.

Submitted by RB on

TSA says the reports were not altered yet names were redacted. Isn't that an alteration?

Who or what agency has set exposure limits for unneeded xray exposure?

TSA says they check each machines radiation output routinely. How often is routinely.

Why keep these devices in service if there is even a slight question about how much radiation these Strip Search Machines are emitting?

I for one find no comfort in the TSA Blog article.

And remember, TSA lies. Always!

Submitted by Anonymous on

How often do safety tests occur on a machine that is operating daily?

The fact that you do safety tests is encouraging, but at the same time it's scary. It means that you admit that these machines, shall they malfunction, could cause very serious medical issues. I don't gamble, I don't buy lottery tickets, I will not step into one of your Russian roulette machines.

Submitted by Anonymous on

We took immediate steps to hold contractors accountable..


But you only found the problems when you were forced to release the information publicly.

Why didn't the TSA discover the errors when the machines were deployed?

Submitted by Anonymous on

1. Everyone of these reports was generated by the vendor, Rapiscan Systems.

2. In all cases, the "errors" had the effect of increasing, apparently substantially, the apparent radiation generated by the device.

4. An error that I saw on a couple of reports was testing the scan for seven seconds instead of three. The form allows for either a three or a seven second test. It seems to me that a higher figure (by over 100%) would be obtained if a device was tested at 7 rather than 3 seconds.

5. Rapisan has a video on its website ( ) showing a reporter going through a scan on one of the "S-1000" single pose" machines. I timed it at 12 seconds between putting the arms up and putting them down.

6. Rapiscan website claims a "throughput" of [I]up to [/I]200 persons per hour. Even if the maximum "throughput" was achieved, this would allow 18 seconds per passenger, easily enough to account for a 7 second actual scan per passenger.

7. I conclude it is likely that the machine can be run on both 3 second and 7 second exposures, yet Rapiscan seems to be asking that it be tested on only the 3 second exposure.

8. It is not obvious to me that inability to divide by ten is the problem here. Consider the language in the standard cover letter:

QUOTE: By design the Secure 1000 prevents significant changes in scan energy, even those still well within the applicable ANSI standard, as even a modest increase in scan energy, while still well within the applicable ANSI standard, [B]would overload the system's detectors and dramatically degrade its imaging ability in a way that would be obvious to the operator.[/B] This design has been independently verified to an extremely high standard.(ENDQUOTE)

9. It appears then, that the sole protection against overdoses of radiation is the operator noting a "degraded image".

10. There is no indication that there was any effort made by either Rapiscan or by TSA to determine whether any operators of the machines in question had noticed a "degraded" image.

11. It seems to me that mechanical fault cannot be ruled out unless there is an inventory of the operator logs. Of course, it is always possible that a "degraded image" was seen, but not logged, and the passenger was simply rescanned.

12. This would be all the more possible if the operators have not been instructed as the fact that a degraded image means there has been a radiation overgeneration. We have no indication that operators have been so trained.

13. The "divide by ten" error is not the only "error" listed in the reports. Other sources of error include "failure to measure background radiation" and "other documentation errors", which are unspecified.

14. Some of the correction reports indicate that the failure to measure background radiation does not affect the validity of the test. I ask if that is so, then why is it necessary to account for it?

15. There is no description of "other documentation errors" but the company has produced a new report form, which includes the following option:

Considerable document errors and/or discrepancies [/B]as noted in the comments below. [B]Corrective action required

16. TSA is going to be irradiating millions and millions of people every month, including children and pregnant mothers. They must do better than produce an X-ray maintenance schedule which permits "considerable document errors and/or discrepancies."

17. All of this points to poorly considered procedures prior to roll out. Is TSA conducting some kind of vast experiment here?

18. It seems likely that with these inadequate reporting procedures, at the time that TSA was assuring us that these machines were perfectly safe, there existed no reliable and consistent means of measuring the radiation produced by the machines.

Submitted by Anonymous on
A large part of keeping the public safe includes using the best technology available.

So, why use TWO DIFFERENT technologies- backscatter X-Ray and Millimeter Wave? Are they Both "best"??

And your own figures don't even add up. First you say "One year of naturally occurring background radiation: 300 millirem", but then you say "One day of natural background: 0.1 millirem". Using that second figure, one year would be 365 * 0.1 = 36.5 millirem. (And, even if it was a misplaced decimal point, it would equal "365", not "300" as mentioned earlier.)

And, you so brazenly lie: "TSA did not alter or edit the reports" and "Names were redacted" cannot both be true. Therefore, one must be false.

Add this lying to a lack of ability to do simple math to the lack of ability to tell time (the whole 'VIPR operation kept going even though no more trains were departing' thing from the other day), and that's about what we expect from the TSA.
Submitted by Fish on

Your tests are not conducted by a third party, nor are they peer-reviewed - therefore scientifically invalid and I certainly don't trust them. No one should.

Submitted by Anonymous on

i see that you are concerned about the public but what about the 1000s of tsos that are around these machine 8-10hrs a day, 2080 hrs/yr? what about their safety?

Submitted by Anonymous on

When exactly did TSA review these "Testing Reports"?

Obviously not before deployment.

Or is the TSA saying they reviewed the report and ignored the problems?

Submitted by Anonymous on

The bottom line is that the TSA has no credibility with law-abiding sensible taxpaying Americans. The TSA has failed in every aspect of management to include people, process and technology, even by your own admission. Your mis-management of the radiation inspection process is yet but another example. The TSA is an distasteful stain on the founding principals of the United States.

An American Taxpayer

Submitted by Ozzie on

TSA, your spin objectives and attempts to flatten public concern and attention here are ridiculously obviouis. First, could you have picked a less news-hungry time than late saturday afternoon? That and perhaps the japanese tragedy unfolding made this a better time than whenever to finally release some of these
reports. Next, your flippant and dismissive characterization of errors in radiation safety tests as "warts and all" belies the fact of how incompetent and
dare I say distracted these contractors were. Let's repeat that last phrase
"errors in radiation safety tests." Also, this spin about how TSA takes safety seriously and uses stringent testing measures is totally contradicted by what you are trying to sneak by us here. Had those measures been stringent you would have seen these errors at the time of deployment, not many, many months after the fact. If your contractors can't record some basic facts and figures then how can we trust the tests you have relied upon - tests that are
the final measure of safety before exposing millions to radiation. If these were just surface warts then why has the agency ordered their complete and immediate retesting? Isn't this an admission that you don't trust the tests and thus, cant vouch for the safety of these machines? If there is any doubt regarding safety that is
triggering the retest shouldn't that same doubt give you pause before exposing millions to additional radiation? It's appalling that in 2008 the GAO blasted TSA for failures in its radiation safety protocols for non passenger technolgy. Within a year or so thereafter you embarked on a super fast rollout of human AIT technology and now
it comes out that the tests are flawed. I look forward to hearing TSA's testimony on this one.

Submitted by Anonymous on

I don't trust the TSA with my health, not a bit.

Submitted by Anonymous on

TSA hold contractors accountable but yet doesnt its own staff, despite a mountain of reports of "isolated incidents", lawsuits and other civil actions.


Submitted by Anonymous on

Well Bob, that's basically what was told to my father, that he was safe from radiation, when he went to work on Amchitka Island between the nuclear tests. I think he figured it out, about the time he was on his deathbed from radiation induced cancer, that he had been lied to and murdered by factions within the US government.

Submitted by Anonymous on

TSO within 8 feet of "nude-o-scope" scanner for 8 hrs. 1 scan every 20 seconds. That's 480 minutes, 3 scans a minute. 1440 scans a day. .005 mrem/scan exposure at source, or 7.2 mrem exposure at source/day. Assuming 5 days a week schedule, that is 5days a week*52 weeks a year*1.440mrem/day exposure at source, or a whopping 1872 mrem exposure/year at source. Assuming that Distance(radiation source) = 1 foot, TSO at 8 feet, deltaD=7feet. Since ERP is output/D^2, your poor TSO is exposed to 1872mrem/49 or 38.2 mrem excess radiation dosage per year from being on the job. And that is just from one of your "harmless" ATI scanners. So, in a year, the radiation exposure of a TSO working a "grope and nuke" line with only 1 properly calibrated scanner picks up 10% more radiation above and beyond normal background.

I wonder about the amount of radiation the operators of the baggage scanners get focused on their gonads. Look at where they sit compared to where the X-ray sources are. If I was a TSO's Significant Other, I'd want my sweetie wearing lead-lined underwear.

As a concerned citizen who will be paying for the medical care of long-term TSO's (a gov. worker rarely quits the gravy-train), why are TSO's not enrolled in a dosimeter monitoring program?

Submitted by Anonymous on

Total radiation means nothing. There are different kinds of radiation, and the effects of backscatter exposure on humans are still unknown. This kind of radiation concentrates on surfaces, such as skin and corneas. In fact, the effects of backscatter on live beings have still not been studied.

Another point of notice is that, although the doses may be low, they are being applied to a huge amount of people, with no benefit at all to these people. A small percentage of people will develop complications from this exposure, and, since the TSA has yet to catch a terrorist, it is safe to bet this will be more people than the number that will benefit from the use of this technology.

Submitted by Anonymous on

And TSA and its employees wonder why many of us opt out? And TSA's employees harass passengers who opt out, which is specifically allowed?

THIS IS EXACTLY WHY I AND OTHERS OPT OUT! X-Rays, radiation, MMV - this is a serious matter and the contents of this particular blog are further evidence that the TSA should not be subjecting the general public to this technology, Fourth Amendment issues aside.

Who is the "contractor"? If it's Rapiscan, then you have even more serious issues. And 12 months is far too long to be dorking about testing these machines. Hire some independent third-party companies to do your testing, allow passengers and employees to wear dosimeters if they choose to, and give us some numbers that haven't been cooked and are truly independent.

TSA and DHS has no business conducting an experiment with health consequences on its own employees and the tax-paying public.

So many of us have been saying this all along and have demanded information - with good reason. The TSA is not capable of responsibly handling this kind of technology, even if there was some way to justify irradiating its employees and travelers. There is no way backscatter or MMV should have been implemented without any of these so-called safegards and quality controls already in place, and tested by an independent third-party contractor. ENOUGH! TSA DOESN'T GET TO PLAY RUSSIAN ROULETTE ON TRAVELERS OR EMPLOYEES!

Submitted by Anonymous on
While these inaccuracies didn’t impact the overall assessment that the technology is safe, they are still unacceptable. We took immediate steps to hold contractors accountable and fix the mistakes,

It sounds like these reports where completely ignored by the TSA until the TSA were forced to release them.

Bob, can you please provide a time line that shows when the TSA first found out about this problem and when the "immediate steps" were initiated?
Submitted by Adrian on

Please stop comparing ambient x-ray radiation with x-rays focused on the surface of the human body. It's misleading. I can comfortably look at a 100 Watt light bulb, because it's diffuse. Looking at a 100 Watt laser beam would cause serious damage, because it's focused. The x-ray backscatter machines focus the x-rays on the victim's skin.

There appear to be no studies available about how focused x-ray radiation affects some tissues, like the corneas of the eyes. Without such information, how can any regulatory body determine what levels of radiation are safe?

When will the TSA release the mechanical design documents and software for independent public review? We need to understand the failure modes of these machines. If a part fails, we need to know that the machine fails in a safe way. Otherwise, hundreds of passengers could be overdosed before the next routine check.

Why aren't TSOs allows to wear dosimeters?

Every machine should have a big serial number on it visible to the entering passenger, and the reports should tally results by these numbers. If I read that a machine at airport XYZ failed, I should be able to figure out if it's one I've gone through.

Why does TSA even use x-ray WBI machines when the inherently safer millimeter wave machines were shown to be just as effective?

When will we get unredacted versions of the radiation studies released last year? (You know, the ones that were supposed to convince us these machines were safe? Big blacked-out sections don't make me feel safer.)

Submitted by Adrian on

The risk of getting cancer from these machines is probably minuscule, but it's not zero. On the other hand, the risk of being a victim of a terrorist attack is also minuscule. Does the TSA have a document that does a risk/cost assessment?

Many other TSA strategies that supposedly make us safer from terrorism actually make us much less safe from more mundane crimes and injuries. Secure Flight greatly increases the risk of identity theft. Not being able to lock our checked bags puts our belongings at more risk of theft. Fear of this theft drives more passengers to bring more stuff in their carry-ons, which results in more accidents when passengers and flight crews are struck by items falling out of the overhead bins.

I'm unconvinced that most of the TSA-imposed risks do enough to offset the chance of a terrorist attack to justify the increased chance of injury that the policies create.

Submitted by Anonymous on

This post is like the Savannah post.

TSA is simply spinning a mistake and this post, along with the Savannah post contains misleading information.

If the TSA wants the American people to trust it, it MUST be more honest. If the misleading information was unintentional, then address it in updates.

Failure to do so only makes the American people think the misleading is intentional.

Submitted by Anonymous on

We have all seen over the last several months numerous efforts by the TSA to mislead the public by outright lying to us, by withholding information, and by attacking whistle-blowers. And THAT is just the tip-of-the-iceberg in terms of the TSA's unethical and immoral actions.

Your claim that the TSA has "transparency" is just another lie, the only thing that is "transparent" at the TSA is a citizens clothes.

Submitted by Adrian on

The RapidScan sheets point out that the measurement process uses a Fluke 451P survey meter. There's also a 2.5 correction factor applied. The correction factor has a footnote indicator, but I cannot find the corresponding footnote.

Curious as to what the correction factor was about, I went looking for information on this meter. From a Canadian government study, I found this conclusion:

The survey meters appear unsuitable for quantifying leakage radiation from small fields that might exist on baggage x-ray machines.

So while they may be fine for measuring the radiation in the passenger's position (where the field is wide relative to the size of the detector in the meter), they're probably not good for all of the external leakage measurements. Are these the same meters that are used to measure leakage from the baggage scanning machines?

Submitted by Adrian on

Is anything done to ensure the machine is working properly mechanically?

The exposure testing is done at two points within the scan area, both at 36" above the floor. My understanding is that these machines work by scanning vertically, and that's mechanical. Is anything done to make sure that mechanism for sweeping is functioning properly?

Assuming the x-ray emitter is physically moved from the top down to the bottom of the unit, does the design of the machine ensure that the movement begins before the emitter is energized? That would reduce the risk that a momentary mechanical stall would result in a significantly larger dose being applied to the head of a typical adult.

In fact, it seems by choosing 36", which is approximately the center of the scan (where the physical transit is most likely to be moving smoothly), RapidScan's procedure minimizes the chance of getting an anomalous reading if the sweep mechanism is uneven.

Submitted by Anonymous on

You guys do realize no matter what you say its not TSAs fault. The entire US government (not just tsa) has a radiation safety requirment for machines that release x-rays. Its the same requirement hospitals, post offices, radiation plants, and everyone else that uses radiation has to follow. The amount and type of radiation and the rate of exposure these machines put out are well below those safety requirments. As for dosimeters, they are only required if a certain amount of radiation is being emmitted from a machine and these machines don't emmit enough to require a dosimeter. Could TSA just give all the TSO's a dosimeter for kicks since they aren't required to wear one? Probably not very cost effective. So honestly you should be thankful because TSA could make their machines stronger and put out even more radiation since they would still be below the GOVERNMENT SAFETY REGULATIONS for radiation. Its not TSA's fault, if you think the machines put out too much radiation get OSHE or however is in charge of it to increase the safety requirments. Of course if you do that it will also reduce the amount of radiation life saving machines like CT scanners and MRIs put out since they have to follow the same standards and regulations.

Submitted by Avxo on

I appreciate the posting of these reports -- warts and all, but I do have some questions:

You state that one year of exposure to background radiation is 300 millirem while at the same time asserting that one day is 0.1 millirem. That can't be right.

Also why do you quote figures in rem units instead of sieverts? Granted, the conversion between the two is trivial, but the fact remains that the rem is somewhat deprecated. Indeed, the NIST mandates the use of sievert in its own publications and strongly recommends it for everyone else.

You had mentioned, in a previous post, that DoD personnel were conducting tests of the machines for radiation on TSA's behalf. Is that still the case? Are their reports available?

Do the machines themselves contain sensors to detect potential malfunctions or increased levels of radiation as part of the normal operation?

Are any movable collimators present in these machines to flatten or otherwise attenuate the x-ray beam generated? If so, how often are they inspected?

Submitted by Anonymous on

From your link:
"After TSA makes an operational decision to use a technology, manufacturers are then required to perform radiation inspections on each individual unit before it leaves the factory and is shipped to TSA. The manufacturer also must perform a radiation test on each unit once it is installed in the airport.

After installation, TSA requires manufacturers and/or maintenance contractors perform periodic radiation tests in accordance with the applicable standards – this happens at least every 12 months."

A simple question: why is the safety testing done by the manufacturer, as opposed to a third party? Who chooses the 'maintenance contractors' in the case that they are the ones doing the test?

Until I know that the machines are being tested by people who have no business interest in the test results, I will not use them.

Submitted by Bill on

Why does your test require you to do 10 scans and take an average? You should do 10 scans and if any one of them fall outside of a set variance the machine should be shut down for maintenance. Average safe levels of radiation don't matter to the one person who gets a higher dose.

Of course you still shouldn't use the machines at all because they are a gross violation of the letter and spirit of the 4th amendment.

Submitted by Anonymous on

Anonymous said:
"So honestly you should be thankful because TSA could make their machines stronger and put out even more radiation since they would still be below the GOVERNMENT SAFETY REGULATIONS for radiation. Its not TSA's fault, if you think the machines put out too much radiation get OSHE or however is in charge of it to increase the safety requirments."

And what government regulations are those? Are you speaking of the FDA regs? The DoD exceptions? ANSI? Do you have any idea what you're talking about?

And you're sure the "GOVERNMENT SAFETY REGULATIONS" are met even when the output is 10 times what's intended?

Submitted by Anonymous on

If you are really serious about this, you should have immediately shut down all back-scatter units until 3rd party reports are released. This has really gone way to far. Good luck putting this cat back in the bag.

And once the TSO's unionize, OSHA is going to step in. I predict lots more opt outs in TSA's future, but i really worry about the TSO's who have to stand next to these things.

Submitted by Anonymous on

I appreciate all the concern for the passenger who may go through one or two times a week...


What are they getting exposed to?

And TSA REFUSES to allow them to wear Dosimeters... why is this???

Why isn't OSHA requiring TSA to supply and mandate dosimeter usage to protect their workers??? Any other industry with radiation exposure is required... hummm...

Also, the x-ray machines they use to screen my carry-on luggage; Yes, there are curtains supposedly to protect from radiation leakage BUT when I'm waiting for my bag to come out and I'm looking for it I've seen the red "activated" light on for the x-ray when my bag is coming out and the curtains are open... How much radiation is coming out of there and exposing myself and the workers?

I really hope all these people who are trying to make my flight safe aren't going to develop cancer or some other horrible disease from their constant exposure to the high levels of radiation!!!

Submitted by Anonymous on

Y'all better stock up in shiny new blue gloves, because there's a whole bunch of us will be opting out.

Submitted by Bubba on


Total radiation means nothing. Types of radiation vary widely, with different biological consequences.

Please publish the results of a simple Ames test on these scanners. Briefly, plate bacteria, scan them a couple of times, and check the bacterial colonies for mutations. This type of test is a standard to check for the ability of chemicals or other stimuli to cause cancer (the result of mutations). It is fast, cheap and simple. There is no reason not to perform it.

Before you test these on bacteria, you won´t be testing them on my skin.

Submitted by Ayn R Key on

The other day I watched a doctor use a 10 watt light to burn off a wart. It was a fascinating process.

Especially since the 10 watt light in my hand, when illuminated, really can barely warm my skin.

Do you think there is a difference between my 10 watt general illumination light and his 10 watt focused red laser?

I think there is the same difference between the general x-rays we are exposed to and the backscatter.

Submitted by Alex on


Where are the reports from the other 50+ airports at which backscatter is in use?

Looking at the release reports, there are 346 listed reports. The first 306 reports correspond to 15 airports. These reports cover the last 27 months and equate to 9 tests per year at each airport for all machines.

I am unsure as to what airports the remaining 40 reports are for. This rate seems somewhat low, but likely within the TSA's acceptable range, if not mine.

However, there are another 50-60 airports that have backscatter technology and are not listed in these reports. Does that mean that only 1 in 5 airports has had even a single x-ray machine tested at all?

Submitted by Adrian on

Anonymous misses several points:

The entire US government (not just tsa) has a radiation safety [requirement] for machines that release x-rays. [It's] the same requirement hospitals, post offices, radiation plants, and everyone else that uses radiation has to follow.

That's simply not true. There are different standards for different applications. Take hospital x-ray machines and CAT scans for example. They are not designed nor intended to be used on the general population an arbitrary number of times. They are used when it's the best way to get important health information. The evaluation is done by the patient and a doctor who is aware of the patient's particular risk factors.

A doctor, for example, is less likely to suggest such a scan for a pregnant woman, for a cancer survivor, or for someone who has had many previous scans for other medical conditions, especially if there is an alternative test available. The TSA makes no risk/benefit analysis when they try to convince every passenger to enter the scanner. (It appears they didn't even do a risk/cost analysis for the purchase of the machines.)

A highly-trained technician runs the hospital device, and the machine is aimed only at the portion of the body necessary. You don't get a whole-body scan to figure out if you have a fractured wrist. Furthermore, these medical devices are for seeing inside. The majority of the radiation is passes through the body and be absorbed by shielding. The TSA machines, on the other hand, are designed to focus the radiation on the skin (and corneas). That's a much, much smaller volume. There is ongoing debate as to whether the "effective dose" factors being used accurately reflect that difference.

As for dosimeters, they are only required if a certain amount of radiation is being [emitted] from a machine and these machines don't [emit] enough to require a dosimeter.

We're not talking about requiring dosimeters for the TSOs. The TSA has prohibited the screeners from wearing them. And they aren't that expensive. A quick web search suggests that there are reputable services available for less than $55 / employee / year. That's not much money compared to the cost of the machines themselves.

[It's] not TSA's fault, if you think the machines put out too much radiation, get [OSHA] or [whoever] is in charge of it to increase the safety requirments. Of course if you do that it will also reduce the amount of radiation life saving machines like CT scanners and MRIs put out since they have to follow the same standards and regulations.

The safety guidelines for the TSOs and the passengers have nothing to do with the amount of radiation emitted by diagnostic medical devices. They are designed for different purposes and used in different circumstances.

It is the TSA's fault for pushing these devices into use, especially when there are safer alternatives, like millimeter-wave scanners, which, like MRIs, do not use ionizing radiation. It is the TSA's fault for lecturing passengers who opt-out of these invasive, unnecessary, and possibly dangerous scans.

Submitted by RB on

And once the TSO's unionize, OSHA is going to step in. I predict lots more opt outs in TSA's future, but i really worry about the TSO's who have to stand next to these things.

March 14, 2011 9:16 AM

No one is forcing these TSA employees to stand there and be irradiated for hours on end.

So the heck with them!

Submitted by Anonymous on

Bill said:
"Why does your test require you to do 10 scans and take an average? You should do 10 scans and if any one of them fall outside of a set variance the machine should be shut down for maintenance. Average safe levels of radiation don't matter to the one person who gets a higher dose."

Very true, Bill. One scan could be 100x the designed irradiation, the next eight 0.001x. The average - assuming by "average" the TSA means arithmetic mean - would fall within limits. I'd sure hate to be the one who got the 100x dose.

Expecting the TSA to understand and properly employ statistics is like expecting them to understand and properly employ Constitutional law. It would be great but it won't happen until it's forced to do so.

"Of course you still shouldn't use the machines at all because they are a gross violation of the letter and spirit of the 4th amendment."

Very true.

Submitted by Anonymous on

This is another attempt by TSA to calm the public by providing incomplete and inaccurate information (and is yet another proof that this government agency has no credibility) Specifically, the total amount of radiation measured in these tests is not relevant since ALL the radiation is focused on very top layer of the skin. In other words, it is not distributed throughout the body, and the equivalent dose received by the skin is orders of magnitude higher (just think of it as focusing all energy of a small heater only on the skin -- you will quickly feel a burn). There has been no testing of this kind of radiation exposure, no animal or other organism studies. The bottom line: the risk is very high, the tests are inadequate, and the gain in security is non-existent. Neither I nor my family will ever go through these machines (and I am a doctor and a scientist, i.e. I believe facts, not fiction). Bob, I know how much you love to delete my posts with hard scientific facts -- try to resist your temptation this time and let the public see how things really are.

Submitted by James on

Once again ... the public doesn't believe you. There is just no credibility to anything that is said because there are no guidelines for anything being done.

How often will the machines be calibrated so they don't go haywire? Why don't the same strict guidelines that govern medical equipment govern these scanners? Why wasn't there long-term testing done on these machines to identify any long term exposure problems?

Here is the big question that I think EVERYONE wants answered! Right now we're all being told again and again it's all safe ... so who is going to be held responsible in 10 years when we find out that these scanners ARE doing damage to the body?

Not for nothing ... everybody thought asbestos was safe too ... look how that one turned out!

Submitted by Anonymous on

The US Nuclear Regulatory blog ( says "The average American is exposed to approximately 620 millirems, or 0.62 rem, of radiation each year from natural and manmade sources." The TSA blog says "One year of naturally occurring background radiation: 300 millirem. Annual recommended limit to the public of radiation from man-made sources: 100 millirem."

I wonder which of the two sources -- if either -- is more credible.

Submitted by Anonymous on


In true TSA form, while discussing the factor of 10 error on the famed survey tests, your published daily millirem dosage is off by a FACTOR OF 10 from the data source listed on the website here: TSA FOIA link and remains so after you have been notified of the error.

Why is this so deliciously ironic???

Do you (or whomever is approving these posts) just not care about your image, do you feel the public doesn't care, or is the TSA just terminally sloppy?

Submitted by Anonymous on

The TSA has lied to, mislead, mis-informed, harassed, withheld information and intentionally deceived the American people constantly over the last several months.

There is NO reason why ANY reasonable person would trust anything you tell us now.

Submitted by Anonymous on

After just having to go through the humiliation and down right dirty feeling of your nude o scope, I find even less comfort in this article. (By the way, having to stand like a person under arrest made me feel really great as well.) Now, even though I try to avoid flying as much as possible,not even will I feel like I need to take a shower after I go through security, I now have to worry even more about being showered with radiation!

Way to go TSA!!! Disgusting!

Submitted by Anonymous on

The backscatter X-ray delivers as much radiation as several minutes in flight, only the X-ray delivers it within several seconds. Isn't it more harmful to concentrate radiation than to spread it out over time?

Submitted by Concerned Observer on

I am highly disappointed. I asked a simple, but important question. Perhaps it was not clear enough. I admit that my wording was off!

Were the scanners that were recorded as putting out 10x more radiation roped off until a new, "normal" reading was taken?
... Or were the old numbers simply tweaked to create "normal" numbers?