Airport security is a major concern for travelers worldwide. With the increase in global terrorism and crime, airport authorities are constantly upgrading their security systems to stay one step ahead of criminals and terrorists. One of the most common questions asked by travelers is whether airport scanners can detect money, especially large sums of cash. In this article, we will explore the capabilities of different types of scanners used in airports and whether they can spot cash and other prohibited items.
Types of Scanners Used in Airports
There are three main types of scanners used in airport security checkpoints – metal detectors, x-ray machines, and full-body scanners.
Metal Detectors
Metal detectors are the most basic type of scanner used in airports. They use electromagnetic waves to detect metal objects on a person’s body or in their belongings. Metal detectors can easily detect metal items like coins, jewelry, watches, and other accessories. However, they cannot detect paper currency or other non-metallic objects.
While metal detectors can sense metal in coins or cash boxes, they cannot specifically identify paper money. Currencies like the US Dollar, UK Pound, or Euro do not contain enough metal to be discerned by a metal detector.
X-Ray Machines
X-ray scanners are commonly used to scan carry-on luggage and other personal belongings at airport checkpoints. These machines use low-level x-ray beams to produce a photographic image of the contents inside a bag or package.
Operators can detect suspicious objects like weapons, explosives and other prohibited items in the x-ray images. However, normal x-ray machines are not designed to specifically target paper currency. A bundle of banknotes would show up as a dense, opaque object on the x-ray, which could prompt further inspection.
X-ray scanners are also used to scan checked baggage before loading onto aircraft. These large machines, like CT scanners, are more advanced and may be calibrated to detect cash, but they are not deployed at all airports.
Full-Body Scanners
Also known as millimeter wave scanners, full-body scanners produce a detailed 3D image of a person’s body to detect concealed objects underneath their clothes. This allows security personnel to spot weapons and contraband like explosives and drugs.
While full-body scanners provide detailed body scans, they do not have the capability to specifically detect paper currency or documents hidden on a person. Any cash or valuables concealed under clothing would be indistinguishable from the body in the scan image.
Advanced Scanners to Detect Money
While standard airport scanners cannot reliably detect cash or financial instruments, advanced imaging technology has been developed that can identify concealed currency:
MRI Scanners
MRI (Magnetic Resonance Imaging) scanners use powerful magnetic fields and radio waves to produce extremely detailed 3D images. Research indicates MRI scanning can be calibrated to detect paper currency stashed in clothing, bags, or wrapped around a person’s body. However, MRI scanners are bulky, expensive, and slow compared to other airport screening technologies.
Terahertz Scanners
Terahertz imaging uses high-frequency electromagnetic waves in the terahertz range to detect concealed objects. Terahertz waves can penetrate fabrics and plastics, and produce distinct signatures for explosives, ceramics, paper products, and metals. Prototypes of terahertz scanners have successfully identified banknotes and passports concealed in clothing and baggage. However, terahertz scanners are still in development and not widely adopted in airports yet.
Backscatter X-Ray Scanners
Backscatter x-ray systems use low-level ionizing radiation to produce highly detailed body scans detecting both metallic and non-metallic objects. While not currently used at US airports, some other international airports use backscatter x-ray to find concealed currency, drugs, or weapons on passengers. However, there are health concerns regarding ionizing radiation exposure from these systems.
Why Airports Scan for Currency
While paper currency itself is harmless, airports and customs officials have good reason to scan for concealed cash:
- Detecting bulk cash can identify smugglers, money launderers, and those involved in illegal activities.
- Scanning for undeclared currency helps enforce customs regulations on legal monetary limits.
- Finding hidden money provides evidence for investigations into financial crimes.
- Discovering concealed cash aids asset forfeiture in criminal cases.
Authorities are especially concerned about uncovering undocumented cash flows that could be tied to terrorism, narcotics, tax evasion or other serious offenses.
Cash Detection Limits of Airport Scanners
The amount and form of cash that airport scanners can reliably detect is limited by the technology used:
Metal Detectors
Cannot find paper currency or cash in non-metallic form. Only useful for detecting metal coins.
X-Ray Scanners
Can detect unusually dense areas that may indicate stacks of banknotes, prompting visual inspection. Effectiveness depends on density & thickness of cash bundle.
Full-Body Scanners
Cannot specifically identify currency or documents. Cash concealed under clothing or in body cavities will not be detected.
Advanced Scanners
MRI, terahertz, and backscatter x-ray systems can reliably detect even small amounts of paper currency concealed in various locations. However, these are rarely used in standard airport checkpoints.
Maximizing Chances of Detecting Hidden Money
Within the limitations of current technology, there are measures airports can take to improve the likelihood of uncovering concealed currency:
- Utilize higher-resolution x-ray systems optimized for organic material detection.
- Employ targeted screening procedures in high-risk locations.
- Provide specialized training to operators to recognize anomalous cash signatures.
- Conduct selective secondary screening of suspicious passengers and baggage.
Multi-stage inspection combining different scanning methods, targeted passenger selection, and specialized operator training allows airport authorities to maximize the chances of finding hidden currency within operational and cost constraints.
Passengers Concealing Cash
Passengers attempting to smuggle large sums of cash through airports employ a variety of strategies to evade detection:
- Stuffing banknotes in garments, shoes, and belts.
- Taping cash to body parts under and over clothing.
- Wrapping plastic-wrapped currency inside food packages.
- Concealing cash in electronic device cavities.
- Putting money in secret compartments in bags, suitcases.
In some cases passengers have attempted to swallow wrapped currency or insert banknotes in body cavities to sneak cash past airport security. However, this poses a lethal choking hazard and is often detected through secondary screening.
Examples of Airport Cash Seizures
Despite limitations of standard scanning equipment, airport authorities around the world have successfully intercepted large amounts of concealed currency through a combination of technology, profiling, and physical inspection:
USA
- Miami International Airport – $26 million concealed in checked luggage.
- Washington Dulles Airport – $234,000 hidden in carry-on bag.
- Newark Liberty Airport – $560,000 strapped to passenger bodies.
UK
- London Heathrow – £140,000 stuffed in shoes and clothing.
- Northern Ireland Interntional Airport – £215,000 in luggage secret compartment.
India
- Mumbai Airport – 78 lakh rupees concealed under garments.
- Kempegowda Airport Bengaluru – 1.2 crore rupees hidden inside underwear.
Australia
- Sydney Kingsford Smith Airport – A$2.6 million in undeclared cash.
- Melbourne Tullamarine Airport – A$1.28 million stuffed into backpack.
In almost all cases, it was passenger profiling, visual inspection, and selective secondary screening rather than x-ray or metal detection that led to discovery of the hidden money.
Legal Consequences of Concealing Cash
In most countries, failure to declare currency in excess of prescribed limits when passing through customs is a legal offense subject to civil penalties or criminal prosecution:
USA
Must declare total cash of $10,000 or more under federal law. Penalties include asset seizure, fines up to $500,000, and imprisonment up to 10 years.
UK
Cash sums greater than 10,000 Euros must be declared. Non-declaration can lead to penalties up to £5000 or seizure of entire undeclared amount.
India
Failure to declare cash above Rs. 20 lakhs punishable by penalty up to Rs. 50 lakhs and jail term up to 5 years.
Australia
Amounts above A$10,000 must be declared or risk penalties up to 300% of cash value for serious offenses.
Undeclared cash may be automatically forfeited by customs authorities in many jurisdictions. Passengers must prove legal source to recover seized money.
Precautions When Carrying Large Cash Amounts
If you need to travel through airport security with significant sums of legitimate cash:
- Research customs regulations about permitted monetary amounts.
- Separate cash into multiple smaller sums under the declared limit.
- Carry proof of legal source of funds documentation.
- Use secure, hard-shell carry-on bags to transport cash.
- Declare you are carrying cash to authorities at checkpoints.
Taking prudent precautions demonstrates transparency and good faith to inspectors, aiding smooth passage through customs areas.
Can Drug-Sniffing Dogs Detect Cash?
In addition to screening technology, many international airports employ drug-sniffing K9 teams to check for contraband. An interesting question is whether trained dogs can literally sniff out concealed currency.
Several key facts about cash-sniffing dogs:
- Drug dogs can be trained to detect cash through its scent – US paper money has traces of cocaine.
- Experiments show dogs can locate as little as 5-10 concealed banknotes.
- Dogs alert to ink, paper, and drugs residual on money – not the value.
- Cash-sniffing is uncommon – drugs are higher priority targets.
So while drug K9 teams can locate hidden currency, in practice this ability is rarely utilized compared to detecting narcotics or explosives.
| Scanner Type | Cash Detection Ability | Other Features |
|---|---|---|
| Metal Detector | None – detects metal only | Inexpensive, Fast, Ubiquitous |
| X-Ray | Limited based on density | Moderate cost, Common for luggage |
| Millimeter Wave | None – identifies objects only | Used for passenger body screening |
| MRI Scanner | Detects paper currency | Expensive, Slow, Rare in airports |
| Backscatter X-ray | Can identify cash and documents | Exposure concerns limit adoption |
Conclusion
Standard screening systems like metal detectors and x-ray scanners used at most airport checkpoints today have very limited capability to detect paper currency and cash. While advanced technologies like MRI and backscatter x-ray can reliably identify concealed money, they are rarely implemented due to operational constraints.
However, through a combination of technology, profiling, secondary searches, and K9 teams, airport customs authorities are able to intercept large sums of undeclared cash on a regular basis. Travelers carrying amounts of money over the legal limit are advised to proactively declare it to avoid severe consequences. While airport scanners may have trouble finding cash, inspectors have many tools at their disposal to catch concealed currency.