What can customs detect?

Officials at customs and immigration are checking travelers for things like whether they have the right documents to be in the country, whether they're legally allowed to be there, and whether they're bringing anything illegal with them.



By 2026, airport customs technology has advanced to include AI-powered X-ray scanners and highly sensitive biosensors that can detect much more than just "drugs and weapons." Modern customs portals can now identify undeclared currency over $10,000, counterfeit designer goods (through sophisticated pattern recognition), and even minute traces of organic material like seeds or unpasteurized cheese that pose a biosecurity risk. In 2026, scanners are particularly focused on lithium-ion batteries and smart luggage with non-removable power banks, which are flagged as fire hazards. Furthermore, customs dogs remain the most effective "detectors" for high-grade narcotics and explosives. Travelers should also be aware that customs "detection" extends to your digital presence; in some jurisdictions, agents can legally inspect your mobile devices for illegal content or evidence of "intent to work" if your visa status is strictly for tourism.

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Generally, customs officers may stop people at the border to determine whether they are admissible to the United States, and they may search people's belongings for contraband. This is true even if there is nothing suspicious about you or your luggage.

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Airport body scanners alert the TSO to threats—mainly weapons such as knives, guns and explosives. They are designed to detect “metallic and nonmetallic threat items,” according to the TSA. Those are things like explosives or knives made out of materials other than metal, like ceramics, says Malvini Redden.

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Airport Scanners Can See Through Everything – Except Paper.

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The majority of checked baggage is screened without the need for a physical bag search. Inspection Notices: TSA may inspect your checked baggage during the screening process. If your property is physically inspected, TSA will place a notice of baggage inspection inside your bag.

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Whole-body imaging technologies can see through clothing to reveal metallic and non-metallic objects, including weapons or plastic explosives. They also reveal a person's silhouette and the outlines of underwear.

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Clothing and Fabric: Certain types of clothing, fabrics, or folds in clothing can create the appearance of an anomaly in the crotch area on the scanner's image. Loose-fitting clothing, heavy fabrics, or items like belts, buttons, or zippers in that area can trigger alerts.

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Airport body searches, or “pat downs” involve being physically pat down by a security officer to confirm that you aren't carrying prohibited items under your clothing. Airport pat downs happen for two reasons: by random chance or because something about your clothing, appearance, or luggage seems suspicious.

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Airport scanners generally show solid masses on the surface area of a person's body and/or in their clothing. If a large cyst or mass appears to stick up above the skin or body outline around it, or looks like a solid mass compared to the area around it, the scanner may reflect that, said Dr.

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A good X-ray scanner will always detect money. Airport scanners can detect even the smallest amount of metal and can detect paper. The scanners will always look after things that look different to the norm. In this case, if the currency is arranged in bundles, it will be more easily detected.

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Powerful x-rays can now be used to rapidly and accurately detect gold in ore samples, thanks to a fancy new technique our scientists have developed.

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The scanners are designed to detect narcotics and drugs hidden in luggage or clothing. If you pass through a full-body scanner, electromagnetic waves, and radiation will provide the image of drugs on screen. If you hide something in socks, shoes, or undergarments, they are caught by the scanner.

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