We use them every time we travel. But how safe are airport body scanners, really?
By Jody McCutcheon
Air travel: it’s both liberating and stressful. It often means we’re going somewhere exotic and exciting, but it also presents factors of inconvenience and danger. Nonetheless, with our proclivities for tourism and business, it’s no wonder that 2017 saw almost four billion passengers in the air, according to the International Air Travel Association. That number is expected to double in the next twenty years.
Yes, air travel is a necessary component of our modern world, but it may be chipping away at our personal privacy and health. Since 9/11 and the 2009 “Underwear Bomber” incident, travel screening has become far more burdensome, not to mention invasive, mainly due to what the industry euphemistically calls “enhanced screening systems.” The full-body scanners used to screen air travellers have generated significant debate. Here’s why.
How Safe Are Airport Body Scanners?
The year after the Underwear Bomber scare, the US Transportation Security Administration (TSA) implemented the use of full-body scanners. These systems allow airport security personnel to detect contraband among passengers without engaging in physical contact (e.g., pat down, strip search). Specifically, full-body scanners are able to detect non-metallic (liquids, gels, plastics, ceramics, etc.) as well as metallic threats.
Two types of full-body scanners have been used: backscatter systems and millimeter-wave systems. The invasive scanning technology of these machines has created unease over privacy issues, while the radiation each emits has caused public health concerns. So, how safe are airport body scanners, really?
These full-body scanners work by reflecting small amounts of X-rays off the scanee’s skin, with the scan lasting about fifteen seconds – pretty long, when you consider a dental X-ray lasts about half a second. The scattered ionizing x-ray energy is captured and processed into a two-sided, chalk-like outline of the scanee’s naked body.
Public concern over the backscatter unit’s privacy invasion has been ongoing for years. A 2012 lawsuit from the Electronic Privacy Information Center against the Department of Homeland Security alleged that the screening procedure was unlawful, invasive and ineffective, and that it violated the Administrative Procedures Act, Privacy Act, Religious Freedom Restoration Act and the Fourth Amendment. Questions were also raised about what the scan can find that a metal detector or physical pat down cannot. Courts ruled that the systems could be used in airports as long as passengers were offered an alternative scanning method – something few travellers even know about.
Subsequently, privacy concerns were allayed by several measures. These include:
- the implementation of technologies that obscure passengers’ faces and make the images less graphic
- the use of a separate room for image analysis
- the modification of computer programming that prevents the saving, storing, printing and transmitting of images.
As for the safety factor, many independent studies have indicated that the radiation dose rate of backscatter units falls below the American National Standards Institute/Health Physics Society standard dose limit of 250 microsieverts (ÃŽ ¼Sv) over a 12-month period. A single scan creates a dose ranging from 0.015 ÃŽ ¼Sv to 0.88 ÃŽ ¼Sv. But that is one scan, in one airport: travellers normally have to pass through the scanner twice, on the way there, and on the way back. However, another study shows that the ionizing radiation from backscatter systems infiltrates organs deeper than the skin, yet still at a rate that’s lower than established health standards.
Perhaps more alarmingly, passengers will be exposing themselves to further radiation once they board the plane. As this study suggests, flying at high altitudes may expose people to more radiation than does any full-body scanner.
Some scientists, including John Sedat, professor of biophysics at the University of California, San Francisco, believes that the method of measurement belies the actual dosage, and therefore the health risks. He states that backscatter system manufacturers and government officials use the same method as that used to measure medical x-ray doses: by averaging the beam exposure over the volume of the whole body. But backscatter x-ray beams merely skim the body’s surface. Basing dosage on this method would significantly raise the measurements, by a factor of ten to twenty times.
Other experts, such as David Brenner, director of Columbia University’s Center for Radiological Research, worry about health risks stemming from repeated exposure, that more people exposed over more time (e.g., frequent flyers enduring cumulative exposure) may result in an increase in malignancies diagnosed across a population.
Further concern surrounds those naturally predisposed to increased risk. Children, for example, have skin that’s more vulnerable to the damage radiation can cause to DNA, resulting in a greater possibility of normal cells becoming cancerous. And some people have genetic mutations that make them more susceptible to breast cancer, as the affected tissue resides close to the skin surface.
It’s little wonder that European authorities outlawed backscatter systems in 2011 – although the UK does use them, and won’t let people opt out of them if they’re chosen for screening. The TSA also banned them, in 2013, but didn’t say whether the ban resulted from health concerns or not. And they haven’t ruled out the possibility of bringing them back in the future.
The second type of full-body scanner, the millimeter-wave unit, doesn’t expose air travellers to ionizing radiation. It’s presumed, therefore, that these machines present no risk for cancer-causing DNA damage. Instead, millimeter-wave systems beam millimeter waves over the body’s surface. (This is the same wavelength that’s used in 5G technology, the potential dangers of which we’ve detailed in Eluxe before.)
Unique properties allow these scanners to pass through lightweight materials such as clothing. The energy reflected back is used to create fairly graphic images of the scanee’s naked body, which in turn are examined in order to identify objectionable items.
In the wake of the backscatter system ban, millimeter waves units have cornered the market. Yet initially, there were so many privacy complaints that manufacturers were forced to add software called Automated Target Recognition (ATR) to the system, allowing for greater privacy.
Basically this new software substitutes a generic outline of a human body for the actual image. Any detected irregularities picked up by the system are marked for further investigation. Yet many cultures have protested that these scans violate their values. For example, Muslim women don’t wonder how safe are airport body scanners; rather, they’re more against strangers seeing their nude bodies. The same could be said for members of the Orthodox Jewish, Catholic and other communities.
The long-term effects of millimeter waves are uncertain, but this study suggests there are no significant tissue-heating effects. And that’s the party line adhered to by manufacturers of millimeter wave units and government officials. However, based on the “as low as reasonably possible” principle, it makes sense that we should minimise our exposure to radiation sources. In this regard, full-body scanners aren’t helping.
How Useful, and Who Benefits?
These scanners were designed to find plastic explosives hidden on a person’s body. However, it’s been argued that any terrorist worth his salt will be smart enough to avoid airport scanners or stick his explosives in a body cavity – scanners can’t reveal those. In fact, they don’t detect low-density items very well at all. A British defense firm reports that the exact materials the ‘underwear bomber’ had on his person (chemicals and liquids) wouldn’t be able to be picked up by scanners today – which is exactly what the scanners were introduced to do.
So why were the scanners so widely introduced if they’re really not all that useful? Well, there was money to be made, for one. Former DHS secretary Michael Chertoff now heads the Chertoff Group, which represented one of the leading manufacturers of whole-body-imaging machines, Rapiscan Systems. For days after the ‘underwear attack’, Chertoff made the rounds on the media promoting the scanners, calling the bombing attempt “a very vivid lesson in the value of that machinery”–all without disclosing his relationship to Rapiscan.
But Chertoff wasn’t the only politician hoping to benefit from the introduction of body scanners: the Washington Examiner ran down an entire list of all the former American politicians that were part of what it calls the “full-body scanner lobby”: Tom Blank, who also worked under House Speaker Newt Gingrich, Chad Wolf–former assistant administrator for policy at TSA, and a former aide to Kay Bailey Hutchison, R-Tex., former congresswoman Helen Delich Bentley, R-Md; and former Sen. Al D’Amato.
The bottom line? When it comes to high-tech screening methods, the TSA has a dismal record of enriching private corporations with failed technologies, and there are signs that the latest scanning devices may just bring more of the same – but this time, it could come with some serious health risks.