TSA X-Ray Body Scanners Out of Airports?
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According to many studies, including a new one conducted by the European Union, the radiation dose from the X-ray scanner is extremely small. It has been repeatedly measured to be less than the dose received from cosmic radiation during two minutes of the airplane flight.
Using those measurements, radiation experts have studied the cancer risk, with estimates ranging from six to 100 additional cancer cases among the 100 million people who fly every year. Many scientists say that is trivial, considering that those same 100 million people would develop 40 million cancers over the course of their lifetimes. And others, including the researchers who did the EU study, have said that so much is unknown about low levels of radiation that such estimates shouldn’t be made.
Still, the potential risks have led some prominent scientists to argue that the TSA is unnecessarily endangering the public because it has an alternative — the millimeter-wave machine — which it also deems highly effective at finding explosives.
“Why would we want to put ourselves in this uncertain situation where potentially we’re going to have some cancer cases?” David Brenner, director of Columbia University’s Center for Radiological Research, told ProPublica last year. “It makes me think, really, why don’t we use millimeter waves when we don’t have so much uncertainty?”
Although there has been some doubt about the long-term safety of the type of radio frequency waves used in the millimeter-wave machines, scientists say that, in contrast to X-rays, such waves have no known mechanism to damage DNA and cause cancer.
The TSA has said that having both technologies encourages competition, leading to better detection capabilities at a lower cost.
But tests in Europe and Australia suggest the millimeter-wave machines have some drawbacks. They were found to have a high false-alarm rate, ranging from 23 percent to 54 percent when figures have been released. Even common things such as folds in clothing and sweat have triggered the alarm.
In contrast, Manchester Airport officials told ProPublica that the false-alarm rate for the backscatter was less than 5 percent.
No study comparing the two machines’ effectiveness has been released. The TSA says its own results are classified.
Each week, the agency reports on various knives, powdered drugs and even an explosives detonator used for training that have been found by the body scanners.
But Department of Homeland Security investigators reported last year that they had “ identified vulnerabilities” with both types of machines. And House transportation committee chairman John Mica, R-Fla., who has seen the results, has called the scanners “badly flawed.”