The Transportation Safety Administration (TSA) is taking another look at the radiation levels emitted from some of its new airport full-body scanners after tests found some devices were emitting radiation that was 10 times higher than normal. Though it will be retesting about 247 backscatter X-ray scanners deployed at airports around the country, the TSA insists the latest radiation findings are the result of a math error.
Last year, the TSA started using whole-body imaging scanners, which produce a virtual-nude image of the body, as a primary screening measure on travelers passing through airport security checkpoints. The TSA uses one of two types of scanners to do so. One type of scanner employs millimeter wave technology, which delivers no ionizing radiation. However, the second type of scanner currently deployed at airports uses backscatter X-rays that expose the individual being screened to very low levels of ionizing radiation.
The flawed tests were conducted on backscatter X-ray scanners that emit ionizing radiation. While the agency says the radiation levels emitted by the backscatter X-ray scanners pose no health risks, a TSA spokesperson told USA Today that new testing will be conducted “out of an abundance of caution to reassure the public.” The TSA also announced steps to require its maintenance contractors to “retrain personnel involved in conducting and overseeing the radiation survey process.”
Not everyone is convinced by the TSA’s reassurances. The TSA “has repeatedly assured me that the machines that emit radiation do not pose a health risk,” Senator Susan Collins, R-Maine, said in a written statement Friday, according to USA Today. “Nonetheless, if TSA contractors reporting on the radiation levels have done such a poor job, how can airline passengers and crew have confidence in the data used by the TSA to reassure the public?”
According to a report on Wired.com, the Association for Airline Passenger Rights is asking the government to stop using the machines until new tests are concluded in May.
Meanwhile, David J. Brenner, Ph.D., D.Sc., director of the Center for Radiological Research at Columbia University Medical Center in New York, N.Y., recently published an article in the journal Radiology asking why backscatter X-ray scanners are being used at all, considering that millimeter wave technology produces no ionizing radiation. He notes that scientists have not been able to independently measure radiation doses from backscatter scanners because they have not been granted access to the machines to verify the manufacturer’s stated doses.
“The risks for any individual going through the X-ray backscatter scanners are exceedingly small,” Dr. Brenner said. “However, if all air travelers are going to be screened this way, then we need to be concerned that some of these billion people may eventually develop cancer as a result of the radiation exposure from the X-ray scanners.”
Dr. Brenner argues that millimeter wave technology should be considered as a first option, since they are similar in cost and functionality to the backscatter machines, but do not expose the passenger to ionizing radiation.
Ionizing radiation is high-frequency radiation that has enough energy to remove an electron from (ionize) an atom or molecule. According to the American Cancer Society, ionizing radiation has enough energy to damage the DNA in cells, which in turn may lead to cancer.
According to Wired.com, the federal government maintains a thousand screenings with a backscatter X-ray scanner equal the amount of radiation of one standard medical chest X-ray. However, there is wide disagreement about the safety of such scanners within the scientific community, and they were not tested with mice or other biological samples before being deployed.
Late last year, scientists from the University of California, San Francisco (UCSF) sent a letter to the White House Office of Science and Technology echoing the concern that radiation from the scanners could damage skin and underlying tissue, potentially leading to skin cancer.