The Transportation Security Administration says that when working properly, the backscatter Advance Imaging Technology X-ray scanners emit an infinitesimal, virtually harmless amount of radiation.
The problem is that the TSA offers no proof that anyone is checking to see if the machines are "working properly."
The TSA ticks off a litany of groups that it says are involved with determining and ensuring the safety of the controversial devices, including:
- The Food and Drug Administration
- The U.S. Army Public Health Command
- Johns Hopkins Applied Physics Laboratory
- The Health Physics Society
Homeland Security has said the justification for head-to-toe scanning was provided last Christmas, when Nigerian Umar Farouk Abdulmutallab tried and failed to ignite a bomb hidden in his underwear on a Northwest Airlines flight from Amsterdam to Detroit.
But the questioning of the TSA's "working properly" assurances becomes even more significant with the numerous reports this year that its screeners sometimes missed as many as seven out of 10 guns, knives and mock explosive devices that government testers tried to sneak through airport check points.
Why Worry About Exposure to Scanners?
People are subjected to hundreds of millions of diagnostic X-rays every year, virtually all without incident. So why all the angst over the TSA's scanners, which, when working properly, emit far lower doses of radiation?
To assure that the doses are as low as they are billed to be, it is imperative to accurately calibrate the machines and carefully monitor their performance.
A spike in the intensity of the scanning beam, or a slowdown or pause in the timing of that beam's sweep across a traveler's body, could cause significant radiation damage, AOL News was told by a radiologist and two radiological health physicists, who are trained and certified to ensure the safety of those exposed to or working with radioactive material.
The FDA and many state radiation safety offices license, inspect and monitor almost all medical radiation devices everywhere they're used. But even identical X-ray machines used in nonmedical government venues fall outside FDA scrutiny, the agency said last week.
Nevertheless, the TSA maintains that when it comes to the safety of the full-body scanners, "everything is working fine," an agency spokesman told AOL News.
"The safety of our scanning systems are routinely and thoroughly tested by the manufacturer, FDA, the U.S. Army, the Health Physics Society, Johns Hopkins Applied Physics Laboratory and others," the spokesman said when asked last month how the TSA knows if the scanning system is safe.
The TSA does do some of its own inspections of the scanners, Sarah Horowitz, another TSA press officer, explained.
"Preventive maintenance checks, including radiation safety surveys, are performed at least once every 12 months," she said.
It sounds reassuring when the TSA lists the organizations as the guardians of the safety of the public passing between the two radiation-emitting walls of the scanners.
For example, the FDA says it doesn't do routine inspections of any nonmedical X-ray unit, including the ones operated by the TSA.
The FDA has not field-tested these scanners and hasn't inspected the manufacturer. It has no legal authority to require owners of these devices -- in this case, TSA -- to provide access for routine testing on these products once they have been sold, FDA press officer said Karen Riley said.
However, she added that the FDA has received no reports of any radiation safety related problems with these products.
The Army Only Surveyed Three Airports
The TSA boasts about having the Army involved in its safety program. The agency's statements suggest that radiological health experts from the respected U.S. Army Public Health Command routinely check the 464 Advanced Imaging Technology units at 75 U.S. airports.
But that's not the case, Fran Szrom, a certified health physicist with the Army Health Command, told AOL News.
Two-person teams from the Army unit performed surveys of the Advance Image Technology X-ray scanners at just three airports -- in Boston, Los Angeles and Cincinnati, she said. And that was all that the TSA asked the Army to do this year.
"They found no problem with excessive radiation exposure, but none of the 15 machines examined had the required warning label 'Caution: X-Rays Produced When Energized,'" added Szrom, whose command has physicians, nurses, veterinarians, toxicologists and other public health specialists with scientific expertise in 60 different health and safety areas.
The TSA also frequently cites a study it commissioned by the noted Johns Hopkins Applied Physics Laboratory. But the Hopkins work did nothing to ensure the consistent safety of those exposed to the radiation from the scanners.
"APL's role was to measure radiation coming off the body scanners to verify that it fell within [accepted] standards. We were testing equipment and in no way determined its safety to humans," Helen Worth, head of public affairs for the Johns Hopkins lab, told AOL News.
"Many news articles have said we declared the equipment to be safe, but that was not what we were tasked to do," she added.
Moreover, the study said APL scientists were unable to test a ready-for-TSA scanner at their lab because the manufacturer would not supply one. Instead, the tests were performed on a scanner cobbled together from spare parts in manufacturer Rapiscan Systems' California warehouse.
"The system evaluated may be configured different than the system deployed to the operational environment," the report said. It added that the APL found two areas in the testing mock-up where escaping radiation could cause exposure to the public that exceeded the annual safe limits.
The TSA also cited the 6,000-member, nonprofit Health Physics Society as endorsing the safety of its scanners. The society has long said "that intentionally exposing people to low levels of ionizing radiation for security screening is justified" if nationally accepted exposure standards are routinely monitored and met.
However, the group says that it did not and does not monitor the safety of TSA's devices -- only that if the devices operate as promised, safety should not be an issue, Howard Dickson, the Society's immediate past president, told AOL News.
"The dose rates are so low that you would expect [the scanners] would have to be grossly out of performance with the national standard to create much of a hazard," Dickson said.
"The press of people moving through the scanners is quite rapid, so no one is staying in there for any sustained period of time," he added. "I'm not saying it's foolproof by any means, but it would be a very unusual condition that would create a hazardous condition."
The physicists society has been considered what used to be called pro-nuke, and many of its members work for the nuclear industry. However, it has often served as an honest broker of information on hot-button and emotional radiation issues.
But despite that reputation, the TSA has refused the society's requests for the data that the agency collects on radiation exposure in and around its full-body scanners.
Instead, Classic said, "all they do is assure us that everything is safe."
"The fact that the information is not readily available to those that want to know, all of a sudden it conjures questions of what exactly is this,'' she said. "What's going on here?"
The TSA told AOL News that "the report is completed but being fine-tuned and thus can't be released."
How Radioactive Is It?
The amount of radiation generated by a properly calibrated full-body device in the typical 15-second-long scan is equal to about an hour of normal background radiation, such as the amount absorbed while walking through a park, the TSA says.
But physicians and most radiation health specialists say there is no "safe" dose of radiation, so any planned exposure must be justified.
John Sedat, a professor emeritus in the department of biochemistry at the University of California at San Francisco, and three of his colleagues -- a physician and two other scientists -- attempted to verify TSA claims that the full-body scanners were safe.
They studied all the available information on the new system and tried to determine the wavelength of the X-rays, the intensity of the energy released in the design and the safeguards built into these devices.
"We found that essentially none of this information was known or made public, and more interestingly, it looked like this technology had not been independently vetted by the scientific community, published, peer-reviewed or even discussed openly," Sedat told AOL News.
"Essentially, all the information was coming from companies that were making the devices, and it looked like it was being parroted by the FDA and the TSA, which didn't seem reasonable," he said.
In April, Sedat and his colleagues sent a lengthy letter outlining their safety concerns to the White House science adviser, John Holdren, asking that several specific areas -- especially an impartial review -- be considered. It was November, seven months later, before the White House replied.
Sedat says he and his colleagues have "some heavily redacted reports which basically just raise more [danger] flags, because it's very far from an independent, outside review."
The bottom line is that the the University of California at San Francisco group isn't any closer to assessing whether there are health hazards from the scanners.
One important point that Sedat challenges in the TSA's statement is that if there's any danger at all, it's only to the very top layer of skin.
"Not so," the scientist told AOL News. The radiation "penetrates the skin, and then as it goes deeper into the tissue it diminishes. But the skin and adjacent tissue is at risk. There is no question about that."
(Schneider is a former member of the Health Physics Society.)