After a long debate, the safety question will be answered -- by Science.
Last year, ProPublica reported that airport "backscatter" machines -- the controversial imaging devices that x-ray the human bodies that pass through airport security checkpoints -- might be more dangerous than the Transportation Safety Administration has led us to believe. Because of their use of ionizing radiation, the investigative news outfit noted, "anywhere from six to 100 U.S. airline passengers each year could get cancer from the machines." The TSA responded to this by claiming that the radiation each machine emits is "negligible," citing several studies to that effect. The agency then, however, moved to replace 91 of the backscatter machines with devices that rely on low-energy radio waves, or "millimeter waves" -- devices that are supposedly safer than their x-ray-using counterparts.
So, wait: Are the backscatter machines safe, or not? Should we be opting for pat-downs, or not? Questions like that, so far, have been answered -- "answered" -- by a long, unsatisfying game of "He Said, TSA Said." In a November 2011 hearing of the Homeland Security Committee, TSA Administrator John Pistole agreed to initiate an independent study on the health effects of backscatter machines. About a week later, though, Pistole told the Senate Commerce Committee that a then-forthcoming report by the Department of Homeland Security's Inspector General would be a sufficient substitute for an independent study. And the matter was left, frustratingly, at that.