Fairfield University professor says certain subgroups - including TSA screeners, airline staff - could face higher risk from full body scanning than general public; studies are needed
(Posted on November 23, 2010)
Scholar sees TSA workers as this society's canaries in the coalmine
Stepped up security measures at airports nationwide has sparked controversy in the wake of terroristic threats to commercial airplanes. Full-body scanning and pat-downs are becoming the norm at checkpoints. The Transportation Security Administration (TSA) says increased security procedures are vital to thwart non-metallic threats, including weapons and explosives, from getting aboard planes. The criticism is mounting as more Americans head to airports during the busy holiday travel season.
When asked whether the average traveler should be concerned over passing through a TSA scanner, Dr. Douglas Lyon, Fairfield University Professor of Computer Engineering, pointed out that TSA full body scanners use ionizing radiation. "Since no studies have been done, and since ionizing radiation without medical necessity is being used on the general public, I would say that the increased risk has not been properly assessed. Ignorance of the harmful effects of low-level long-term radiation requires that we engineer on the side of caution. DNA is very sensitive to damage from ionizing radiation. It's time to take consumers' health seriously."
Dr. Lyon further explained, "Considering the ionizing radiation is focused on the skin (not the entire volume of the human body) and that the dose is chronic, it would be unethical not to disclose the added risk. The general public is probably not at as much risk as other subgroups - TSA screeners, airline staff, frequent fliers, children, pregnant women, among them."
Airline staff members are already in a high-risk group, according to Dr. Lyon. He cited a study as an example: 'Occup Environ Med. 2000 March; 57(3): 175-179.' "The study shows a high occurrence of malignant melanoma among pilots... Take a look at the Nordic study [in which it was found that pilots flying international routes have higher rates of skin cancer (http://www.rense.com/ufo6/pilots.htm). Rates for pilots flying international routes were 15 times higher than expected and 25 times higher for pilots flying routinely from Iceland to the United States."
"What we have here is a device that can do harm. The question of how much harm, remains open," he added.
"TSA Full body scanners use ionizing radiation," Lyon elaborated. "The (Occupational Safety and Health Administration) OSHA limit for radiation exposure to adults working with radioactive material is 5,000 mrem. Some reports are that the TSA scanner has only 0.005 mrems (a unit used to measure the amount of biological damage caused by ionizing radiation), which, if true, is a negligible dose of radiation."
"On the other hand, exposure to ionizing radiation over an extended period of time is called chronic exposure," he continued. "The linear dose-response model suggests that any increase in dose, no matter how small, results in an incremental increase in risk."
"No long-term studies have been done on the health effects of the TSA scanners," Lyon said. "A TSA worker can get more than 500 screening doses of radiation per hour. If we assume that the worker gets exposure to 0.005 mrems (a worst-case assumption) then they are getting more than 2.5 mrems per hour. That would be a big concern. But the TSA workers would have to be exposed to the full-scan radiation, without shielding. It is hard to know what the TSA workers are exposed to during normal operation of the machine," he said.
"The TSA workers will be this society's canaries in the coalmine," Lyon noted. "If the full-body scanners are unsafe, we should see the effects in the TSA workers, first. TSA screeners are covered by the OSHA ionizing radiation standard. OSHA has NO established limit on the amount of additional radiation that is safe for a fetus in a pregnant worker (or the general public, for that matter)," he said. "Typically, in medical imaging, as in other tests, there is a medical need for the test. Thus, balancing the risk-reward equation. The question of how TSA scanners balance the risk-reward equation remains open and the assertion that they are a 'safe' source of chronic radiation requires that we answer what we mean by safe. Is having them safer than not having them? And if so, by how much?"
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Vol. 43, No. 127