Airport Body Scanners: Are They Safe Or Invasive?

Airport body scanners have been a topic of concern for travellers, especially with the rise in security measures post-9/11. While these scanners are designed to detect contraband, weapons, and explosives, there are questions about the safety of the technology used, particularly regarding radiation exposure. The two primary types of body scanners are backscatter X-ray scanners and millimetre wave scanners, with the former using ionizing radiation and the latter non-ionizing radiation. While the potential health risks of ionizing radiation are well-known, the extremely low doses used in backscatter X-ray scanners make it challenging to determine their cancer risk. However, millimetre wave scanners, which are more commonly used, emit even lower levels of radiation, equivalent to a fraction of the energy from a cell phone, making them significantly safer.

Millimeter wave scanners emit low-energy waves, similar to cell phones

Millimeter wave scanners emit low-energy waves, similar to those emitted by cell phones. This form of electromagnetic radiation is non-ionizing, meaning it does not have enough energy to remove electrons from atoms. Instead, it can only move atoms in a molecule around or cause them to vibrate. Millimeter waves are also larger than X-rays, and they do not penetrate the skin.

Millimeter wave scanners use two antennas that rotate around a person's body to emit millimeter waves. These waves pass through clothing and bounce back to the scanner, which uses the reflected energy to construct a 3-D image. This image is then sent to a remote monitor for analysis. The technology can detect both metallic and non-metallic objects, including weapons, explosives, and other contraband.

Millimeter wave scanners are considered safe due to the low energy of the waves they emit. The energy emitted by these scanners is thousands of times lower than that of a cell phone. The U.S. Food and Drug Administration (FDA) has set standards for machines that produce radiation, including millimeter-wave scanners, to ensure their safety.

In addition to safety, privacy concerns have also been raised about millimeter wave scanners. To address these concerns, measures have been implemented, such as blurring faces, using generic body outlines, and separating security personnel from passengers. These measures aim to protect the privacy of individuals undergoing scanning.

Backscatter X-ray scanners use low-dose X-rays

Backscatter X-ray scanners are an advanced form of imaging technology that uses very low-dose X-rays to detect hidden objects on or inside a person's body. Unlike traditional X-ray machines that rely on the variation in X-ray intensity transmitted through the target, backscatter X-ray detects the radiation reflected from the target. This technology is particularly useful for security purposes as it can detect objects such as plastic explosives, drugs, and non-metallic weapons that may not be visible on traditional X-rays or metal detectors.

The use of backscatter X-ray scanners in airports has been a subject of debate due to privacy and health concerns. Privacy groups, such as the American Civil Liberties Union (ACLU), argue that the detailed images produced by these scanners violate citizens' personal rights and can be considered a form of virtual strip search. In response, the Transportation Security Administration (TSA) has implemented measures such as blurring facial features, using generic body outlines, and separating security personnel from screened individuals to address these privacy concerns.

Regarding health concerns, backscatter X-ray scanners emit low doses of ionizing radiation, which is considered carcinogenic even in small amounts. However, the doses used in airport scanners are believed to be negligible for individuals. According to studies, an individual would need to undergo thousands of scans to receive a radiation dose equivalent to a single dental X-ray or chest X-ray. Additionally, the radiation exposure from a backscatter scan is comparable to the natural radiation exposure during a few minutes of flight time. The risk of health effects from backscatter X-ray scanners is considered extremely low, and guidelines are in place to ensure the safe use of this technology.

While the benefits of backscatter X-ray scanners in enhancing security are evident, it is essential to balance these benefits with potential risks to privacy and health. Independent testing and ongoing research are crucial to verify the safety of this technology and address public concerns.

Metal detectors use non-ionizing radiation

Metal detectors create a magnetic field by using a brief pulse of electrical current. If there are any metal objects within the magnetic field, the magnetic field will be reflected back to the machine. The machine will then detect this return signal and produce a beeping noise to alert the agent. Metal detectors can identify various metal objects, such as watches or belt buckles, while ignoring very small amounts of metal, like the button on a pair of jeans or small earrings.

The use of non-ionizing radiation in metal detectors allows for the detection of hidden metal objects without exposing individuals to high levels of radiation. This makes metal detectors a safe and effective tool for security screening in airports and other public places.

It is important to note that while metal detectors emit non-ionizing radiation, other airport security devices, such as backscatter x-ray machines and cabinet x-ray machines, utilize ionizing radiation. These machines are designed to scan luggage and create images of the contents. Unlike non-ionizing radiation, ionizing radiation has sufficient energy to knock electrons out of atoms. While the doses of ionizing radiation emitted by these machines are generally low, there are still concerns about potential health risks, especially for vulnerable subgroups of individuals.

In summary, metal detectors in airports and other security settings use non-ionizing radiation to safely and effectively detect metal objects on individuals without exposing them to harmful levels of radiation.

Privacy concerns have been raised about body scanners

In response to these privacy concerns, the TSA has taken several steps to ensure the privacy of passengers. They have implemented technology that blurs the images of the face, installed software to make the images less provocative, and separated the security personnel who view the images from the passengers, so that the screeners never see the passengers directly. Additionally, the TSA has made it impossible for scanners deployed in airports to save or export images.

Despite these assurances, there have been reports of tens of thousands of scanner images that were improperly saved and disseminated, raising concerns about the privacy of passengers. Religious groups, the American Civil Liberties Union, and the Electronic Privacy and Information Center (EPIC, a public interest research center) have protested the use of body scans, with EPIC filing a suit in federal court against the Department of Homeland Security.

In 2013, the TSA removed about 200 full-body scanners after protests because the scanners used low levels of radiation to create what resembles a nude image of screened passengers. Critics called the device the "nudie scanner" before the TSA ended its contract with the manufacturer. Three years later, Congress adopted legislation requiring that all full-body scanners used at U.S. airports include privacy software filters that keep the devices from showing details of a traveler's body on the screens monitored by the TSA.

Health risks of body scanners are reportedly trivial

The health risks of body scanners are reportedly trivial. The Transportation Security Administration (TSA) considers the risk of harm from body scanners to be minimal. The amount of radiation emitted by backscatter x-ray scanners, which use ionizing radiation, is extremely low. The energy delivered by each scan is a small fraction of the energy emitted by a cell phone. Millimeter-wave scanners, on the other hand, use non-ionizing radiation and emit even less energy than backscatter x-ray scanners.

The potential harm caused by ionizing radiation depends on the dose. At low doses, cells can repair biological damage caused by radiation rapidly. At moderate doses, cells can be permanently altered, leading to cancer or other abnormalities. However, the doses of ionizing radiation from backscatter x-ray scanners are so low that it is uncertain if they pose any health risk at all.

To put this in context, an individual would need to undergo 50 airport scans to equal the exposure of a single dental x-ray, 1,000 scans for a chest x-ray, and 4,000 scans for a mammogram. The radiation exposure from a single scan is equivalent to 3-9 minutes of exposure to naturally occurring sources of radiation. Additionally, the amount of radiation received from a backscatter machine is comparable to the amount of cosmic radiation received during two minutes of flight.

The U.S. Food and Drug Administration (FDA) has the authority to set standards for machines that produce radiation, including security screening systems. The FDA requires that all machines be correctly calibrated and maintained to ensure safe use.

While there have been concerns about the privacy and efficacy of body scanners, the health risks associated with their radiation exposure are considered negligible.

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