Health risk? TSA airport scanners and radiation exposure

8:04 PM, Nov 24, 2010   |    comments
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Kucinich wrote to Transportation Security Administration Chief John Pistole, requesting information and clarification regarding the safety of airport scanners.

Kucinich's entire letter can be read below.

Dr. James O'Donnell, a professor of radiology at Case Western Reserve School of Medicine and the Director of University Hospitals Division of Nuclear Medicine, says you're naturally exposed to higher levels of radiation every day than what you'd get in an airport scanner.

He says radiation is all around us in different forms, from sunlight, to cell phones, computer screens, lights, bricks and other natural occuring sources.

In a year, the average Clevelander receives the radiation equivalent of about 20 chest x-rays, or 200 millirems. Someone from Denver, a mile above sea level, is exposed to double that level.

Dr. O'Donnell says the level in an airport full-body scanner is about .005 of 1 millirem, meaning you'd need to go through it about 10,000 times to get the equivalent of a year of exposure in Cleveland.

However, while scientists are aware of the dangers of large doses of radiation at once, Dr. O'Donnell says there's no real data over how much is too much over a lifetime.

Cancer patients who are treated with radiation may be good examples of how much the human body can tolerate and many go on to live years longer cancer-free.   

Some aren't convinced the scanners are safe and want TSA to prove the levels are what they say they are and that they're monitored to prevent accidentally giving someone a higher than normal dose. 

The following is the full text of Congressman Kucinich's letter:

Dear Mr. Pistole:

I write with concerns about the potential health effects of the "backscatter x-ray" technology that TSA is using widely to screen airline passengers.  Workers and travelers are likely to sustain the highest exposures to the technology, which has the potential to cause chromosome damage and can lead to cancer.

TSA argues publicly that the amount of radiation exposure is small.  TSA claims that the exposure is equivalent to the amount of radiation the passenger will receive in two-minutes of flying at 30,000 feet.

Assessments of risk such those upon which TSA has relied are sometimes based on false assumptions that downplay the actual risk to individuals.  For example, we know that there is no amount of radiation that is harmless.  It is the cumulative amount of radiation that causes chromosome damage and cancer.  I wonder whether the numerical risk cited by TSA rests on the assumption that the exposure in question occurs in isolation.

If a person were receiving radiation exposure only from the backscatter technology, the risk could be dramatically different than if the backscatter exposure were to occur in addition to other exposures, such as those from flying at altitude.

Furthermore, the amount of exposure is greater than TSA contends.  According to Dr. David Brenner of Columbia University:

"The number given [by TSA] is what the whole body receives on average. However, the whole body isn't actually receiving the radiation exposure. The skin on the scalp receives 20 times the average dose that is typically quoted by TSA and throughout the industry. It's still a low dose, but it's much more than what's usually said."

Dr. Brenner believes that this kind of exposure could lead to additional cases of basal cell cancers:

"The concern is that radiation promotes pre-existing damage....Since the cancer rate is so high for basal cell carcinoma, this number could be multiplied further by radiation risks."

These concerns are echoed by David Argard, a biochemist at the University of California:

"While the dose would be safe if it were distributed throughout the volume of the entire body, the dose to the skin may be dangerously high."

"[T]here really is no threshold of low dose being OK. Any dose of X-rays produces some potential risk."

And, of course, all of this assumes that the amount of exposure is only what is intended.  In a TSA memo to Robin Kane, Assistant Administrator of operational Process & Technology dated October 9, 2010, Domenic Bianchini, the General Manager of the Passenger Screening Program noted that the scanners are tested twice; once at the factory and once upon installation, to ensure emissions levels are as expected.

But unexpectedly high exposures can occur without knowledge if the machine malfunctions or if there is operator error.

Peter Rez, a professor of physics at Arizona State University, believes that the possibility of a malfunction is an even greater concern:

"The thing that worries me the most, is not what happens if the machine works as advertised, but what happens if it doesn't."

In 2009, it was revealed that a hospital had over-exposed over 200 patients to radiation at 8 times the normal amount during CT scans.  The exposures persisted for 18 months.  According the New York Times, "The hospital blamed its own flawed procedures for the overdoses."  In another case in a different hospital, a 2½-year-old boy received 151 CT scans in about an hour. In both cases, the machine did not prevent the excessive exposure.

Because the safety of the backscatter machines is far from settled, and because the health of the flying public and airport workers is at stake, a closer look is warranted.  Please provide the scientific research upon which TSA relies to characterize the risk to airline passengers and to workers, including TSA employees and non-TSA employees.

In addition, abiding trust in the machines to perform as hoped is misplaced.  The risk to workers and travelers of incurring radiation exposure beyond that expected by the TSA is sufficient to warrant an aggressive monitoring program.  For decades, radiation dosimeters have discovered unplanned radiation exposure to workers, workers' families, and the general public in settings as disparate as nuclear power plants and commercial laundry facilities.

The absolute minimum TSA must provide under the circumstances is a monitoring program that includes personal monitors for non-TSA and TSA employees, including those working near the luggage x-ray machines; stationary monitors for areas in which incidental or direct radiation exposure is expected; and monitors for randomly selected passengers, who are receiving the bulk of the intended exposure.  I stand ready to help TSA implement such a program in the coming weeks.


Dennis J. Kucinich

Member of Congress

Bottom line, for those who still have concerns, they may choose to have TSA agents use the "pat down" method or they may choose not to fly at all.


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