You shuffle through the security line at O’Hare or LAX, step into the scanner, raise your arms for three seconds, and walk out the other side. You barely think about it. Maybe you should.
Airport body scanners have a strange and uncomfortable history that the TSA doesn’t love talking about. The machines you walk through today are not the machines that were first rolled out. The original versions were so invasive that pilots refused to use them, flight attendants lobbied Congress, and the ACLU called them virtual strip searches. And while the current technology is a lot less graphic, there are still some things happening during that three-second scan that most travelers have no idea about.
The Original Scanners Showed Everything
Let’s start with the part that sounds like an exaggeration but isn’t. The first generation of full-body scanners deployed in U.S. airports — called backscatter X-ray machines — produced images that were, by any honest description, extremely detailed. We’re talking outlines that showed genitalia, breasts, buttocks, fat creases, catheters, piercings, and prosthetics. TSA staff sitting in a back room could see all of it on their screens.
The TSA’s response was to put the person viewing the images in a separate room so they couldn’t see the actual passenger walking through. That was the privacy solution. One person saw the body. Another person saw the face. The idea was that no single agent would connect the naked image to the real person.
If that feels like a flimsy workaround for what amounts to a digital strip search, you’re not alone. A former TSA officer named Jason Harrington wrote a piece in Politico in 2014 confirming that piercings and even hernias could be seen on those scanners. This wasn’t a glitch. It was how the machines were designed to work.
They Told Us the Images Couldn’t Be Saved. They Were.
Here’s where it gets worse. The TSA insisted that the scanners deployed in airports were configured so they could not save or export images. That was the official line. But the machines themselves had the built-in capacity to store and transmit images — the TSA just said they’d turned that feature off.
Then reports surfaced of tens of thousands of scanner images that had been improperly saved and shared. Not from airports, technically — from a federal courthouse in Florida that used the same backscatter technology. A U.S. Marshal had stored over 35,000 images. Some ended up online. So the claim that these machines “can’t” save images was really more like “we promised not to.” Big difference.
In response to all of this, the Electronic Privacy Information Center sued the Department of Homeland Security. Their lawsuit alleged the scans violated the Fourth Amendment, the Privacy Act, the Religious Freedom Restoration Act, and the Video Voyeurism Prevention Act. That’s quite a list of laws to potentially break every time someone flies to visit their in-laws.
Pilots and Flight Attendants Got Themselves Exempted
Here’s a detail that says a lot: the people who fly for a living didn’t want to go through these machines. In 2010, pilot and flight crew unions successfully lobbied to change the requirements so they could skip the body scanners. Flight attendants followed with their own successful push in 2012.
Their concern wasn’t just privacy — it was radiation. The backscatter machines used low-dose X-rays, and when you’re going through security multiple times a week, even small exposures add up. Pilots didn’t want to gamble on it. And if the people who spend more time in airports than anyone else decided the scanners weren’t worth the risk, that should have told the rest of us something.
The European Union apparently agreed. They banned backscatter machines entirely in 2011 due to health and safety concerns. The U.S. kept using them for two more years.
How Much Radiation Were You Actually Getting?
In fairness, the actual radiation numbers from the old backscatter machines were genuinely small. An independent task force from the American Association of Physicists in Medicine measured the Rapiscan Secure 1000 SP — the model that was most common in U.S. airports — and found that one full scan delivered about 11.1 nanosieverts of radiation.
To put that in context, the radiation you get during an average two-hour-and-fifty-minute flight — about 9.4 microsieverts — is nearly 1,000 times more than one scan. You’d need over 22,500 scans in a single year to exceed the maximum safe yearly dose. One scan was roughly equal to 12 seconds of radiation during the flight itself.
So was the radiation dangerous? Almost certainly not for a casual traveler. But some scientists pointed out that ionizing radiation always carries some risk, especially for skin cancer, and because cancer can develop years after exposure, you’d never be able to draw a direct connection back to a specific scan. For frequent fliers and airport employees standing near these machines all day, even a tiny risk gets multiplied.
The Machines You Walk Through Now Are Different
The backscatter X-ray scanners were pulled from U.S. airports by early 2013. The official reason the TSA gave was that removing them would speed up wait times. A TSA spokesperson said they were “replacing some of the older equipment.” But let’s be real — years of lawsuits, public outrage, a European ban, and pilot exemptions surely had something to do with it.
Today’s machines use millimeter wave imaging. Instead of X-rays, they bounce radio waves off your body. No ionizing radiation. And instead of showing a detailed image of your actual body, the screen displays a generic outline — kind of like a gingerbread man. It’s the same cartoon figure for every single passenger, regardless of body type. If the scanner detects something suspicious, it highlights the spot on the generic outline with a yellow box.
You can actually see the screen yourself as you step out. It’s right there. If everything is clear, it flashes green. If something triggers an alert, the TSA agent will check that specific spot. No more back rooms with naked silhouettes on a monitor.
Sweat, Lotion, and Hair Clips Will Set It Off
The current millimeter wave scanners have a pretty embarrassing flaw: they go off all the time for things that aren’t threats. We’re talking hair clips, underwire bras, body piercings, and even an AirTag left in your pocket. But here’s the weird one — sweat. If you’re a nervous flier or you just sprinted to your gate, the moisture on your skin can trigger an alarm because of how the radio waves bounce off water.
Glycerin, the ingredient found in a lot of hand lotion, soap, and baby wipes, has also been known to cause false alarms. So if you moisturized before heading to the airport, congratulations — you might get pulled aside for a pat-down.
According to a ProPublica report cited by Scientific American, the false-positive rate on these scanners is around 54 percent. That means more than half the time the machine flags something, it’s nothing. More than half. And the TSA says that information about what these machines can and can’t actually detect is classified.
You Can Always Say No
A lot of people don’t know this: you can opt out of the body scanner entirely. You just tell the TSA agent. They’ll call for a same-gender officer to give you a full-body pat-down instead. The agent will describe in detail what they’re going to do before they do it. You can request a private room.
The catch? It takes about five minutes. And during that time, your bags are sitting on the belt unattended, which is ironic because TSA rules technically require you to keep your belongings within eyesight at all times. Something to keep in mind: put your wallet, passport, and phone in your carry-on before the belt, not in a bin by themselves.
Someone Actually Tried to Sell You Scanner-Blocking Underwear
When the backscatter machines were still in airports, a cottage industry popped up around scanner anxiety. A company called Flying Pasties sold stick-on inserts designed to block the scanner from showing your private parts to screeners. Another brand, Rocky Flats Gear, went further and claimed their products could partially shield you from X-ray radiation.
Those products are basically irrelevant now that backscatter machines are gone. But the fact that a market existed for scanner-blocking underwear tells you everything about how the public felt about those original machines. People were so uncomfortable that they were willing to stick metallic pasties to their bodies before going through airport security. That’s not normal. That’s what happens when trust breaks down.
The Senate apparently thought things had gotten bad enough that in February 2011, they voted to make misuse of scanner images a felony. The fact that they felt the need to pass that law is maybe the most telling detail of all. Nobody passes a felony law for a problem that doesn’t exist.
So the next time you step into that scanner and hold your arms up, just know: things used to be a lot worse. But the machine is still flagging your lotion.
