The new “strip search” scanning machines at airport security checkpoints are increasingly causing furor over issues of privacy, decency and health. Over the weekend, a passenger in San Diego, software engineer John Tyner, opted out of a scan, then warned a security agent not to “touch my junk” during the enhanced pat-down check — that interaction, which Tyner recorded on his cell phone and posted online, went viral, further stoking the public’s frustration.
Whether or not you feel the new backscatter body scans (let alone the security gropes) are an overly humiliating invasion of privacy, there’s no arguing that the scans expose you to extra radiation. Many passengers and some scientists say the excess radiation exposure could pose a health hazard to frequent fliers and to young children. (More on Time.com: 6 Common Sources of Radiation In Your Life)
For its part, the Allied Pilots Association, the pilot’s union, publicly advised its members — who are scanned two to three times per day during the course of their work — to opt for private pat-downs instead of the scan, noting that “airline pilots in the United States already receive higher doses of radiation in their on-the-job environment than nearly every other category of worker in the United States, including nuclear power plant employees.”
The Transportation Security Administration (TSA) and Department of Homeland Security maintain that the scanners emit safe levels of radiation, which DHS director Janet Napolitano called the “equivalent of about two minutes of flying” during a press conference.
But the scans may be exposing passengers to more radiation than Napolitano is letting on. Healthland’s Alice Park wrote in October that many scientists doubt the accuracy of the scan manufacturer’s and government’s calculation of low exposure:
After studying the degree of detail obtained in the seconds-long scans, the scientists wondered how the radiation exposure could be so low. The answer, they concluded, lay in how the manufacturer and government officials measured the dose: by averaging the exposure from the beam over the volume of the entire body. This is how scientists measure exposure from medical X-rays, which are designed to zap straight through bone and tissue. But backscatter beams skim the body’s surface. Sedat and his colleagues maintain that if the dose were based only on skin exposure, the result would be 10 to 20 times the manufacturer’s calculations.
That’s a huge difference, but the higher amount, TSA and FDA officials maintain, still falls within the limits of safe radiation exposure. Based on measurements conducted by the FDA as well as by technicians at Johns Hopkins University and elsewhere, says the FDA’s Daniel Kassiday, “We are confident that full-body-X-ray security products and practices do not pose a significant risk to the public health.”
But that may depend on how much excess radiation you’re already getting — again, a particular problem for frequent fliers. As Healthland reported in September, flying itself contributes to many Americans’ yearly load of radiation exposure — at flight altitudes, people are exposed to perhaps hundreds of times more radiation from the sun and stars than at sea level. (More on Time.com: Body Scans: What You Need to Know About New TSA Security)
Some studies of frequent fliers such as pilots and flight attendants have associated elevated risks of certain malignancies with occupational radiation exposure. In one study, the California Department of Health compared the cancer death rates of California-based female flight attendants to those of a control group of female residents. They found no increased mortality among flight attendants, but they did find a 30% increased risk of breast cancer and twice the risk of malignant melanoma, according to a guide [PDF] distributed by the Association of Flight Attendants. Add to that excess radiation from airport scanners, and it seems prudent for airline professionals to take extra precautions.
What does that mean for the average American? Flying is not typically considered a health threat. By the numbers, we get about 370 millirems (mrem) of radiation per year from various sources, including flight, which is well below the limit of 50 mrem per month set by the National Council on Radiation Protection and Measurements (NCRP).
The common sources of your daily radiation exposure may surprise you, though, so check out Healthland’s Guide to Daily Radiation.
For more on what to expect at airport security this holiday travel season, see NewsFeed’s comprehensive report and interview with a TSA spokesperson: Pat-Downs 101: Nine Things to Know About Your Thanksgiving Airport Screening.
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