Sweaty butts are setting off airport security, and here’s why

Summer travel is well under way, and with it comes long lines, anxiety, and lots and lots of sweating. What you may not know, however, is that a sweaty crotch can actually lead you to be detained as you go through security.

According to The New York Post, Redditors are commiserating about their shared humiliation being detained because of “swamp crotch” at security as they attempt to catch their flights at the airport. The original poster shared her experiences where two different times on the same trip “airports flagged my crotch at the arms up scanner.” She was not alone, she would soon find out. “Big ‘!!’ warning on my crotch on the screen,” one poster responded about another trip they had taken. “This happens to me when I'm late for a flight because I'm sweaty. If you went through the machine that makes you put your hands above your head, it senses moisture. I've been stopped for additional screening twice,” another added.

If you're sweaty like Ted Striker in Airplane, you may get a little more attention at the airport. Giphy

Interestingly, this is a longstanding issue as it relates to airport security. Nearly 14 years ago, ProPublica chronicled a similar phenomenon where airport millimeter wave scanners were regularly creating “false alarms triggered by folds in clothing, buttons and even sweat.” But it still happens now. “Perspiration is probably the weirdest thing that can set off the scanners,” Dr. Shawna Malvini Redden told Reader’s Digest in 2024, also chronicled by the Post. By that point, Redden had been researching the TSA for some 14 years. That same aforementioned millimeter wave technology is the culprit, because those “waves bounce off water,” no matter what or where the water is or what form it’s in. Back in 2011, there were “false alarms” that happened with millimeter wave technology about 54% of the time in Germany, so often that the country no longer uses this particular technology.

While we hope airport security is smooth sailing like in Catch Me if You Can, sweat may make it a little more time-consuming. www.youtube.com

When the scanners launched nearly twenty years ago, ProPublica shares that “TSA officials boasted that [scanners] were so good at detection, that screeners could literally see the sweat on someone's back.” Sweat even became part of detecting explosives: it became necessary for officers to “recognize normal sweat patterns…because something taped or glued to the body changes the natural sweat pattern.”

On Key & Peele, Jordan Peele shows us how sweat and nerves combine. Giphy

Sweat is not the only thing that can set off a scanner either: everything from tumors (yes!) to thick hair, body piercings to underwire bras might make your trip through security more, uh, involved than you might have anticipated. But not to worry: scanners are safe, and they are meant to make your trip through the airport safe, too.

If you know you are usually sweaty at the airport, whether due to nervousness or anxiety, or because you are coming from someplace humid, you may want to either change clothes before security or prepare for a little extra attention. Just know it is in large part because the airport is trying to do its job to protect you. Knowing why it might happen might make it a little less humiliating. A little.

Being prepared for the airport can make you feel like Ryan Bingham in Up in the Air (in a good way). www.youtube.com