While covering the body scanner controversy, I spoke to a TSA official and made several trips to Reagan National Airport to observe use of the machines there. Here's some of what I saw and learned:
Body Scanning: Fast Facts
- The machines were not labeled as "body scanners," nor were there any images posted by or on them showing what they do. Several seasoned travelers told us they didn't realize they were in a body scanner until they were asked to raise their arms.
- About half of the passengers we spoke to were unaware that body scanners were in use, or were even part of a controversy.
- The TSA reports 99 percent of travelers consent to the body scanners. However, the consent is neither verbal nor written (in other words, nobody will ask you if it's okay). Your consent is presumed if you walk into the machine without objecting.
- Body scanning took about the same time as passing through the adjacent metal detector; less when you count those sent through the metal detectors for a second try after removing a belt or pocket items.
- Only occasionally were passengers routed to body scanners. The vast majority went through metal detectors only. TSA agents present would not say how passengers were selected for scanning.
- Nobody "opted out" of the body scanners. It's also interesting to note that no opt-out choices were presented. In other words, to opt out, a traveler would have to realize he was being directed into a body scanner, understand that he had a choice, and stop and speak up to a TSA agent.
- As of last weekend, 400 body scanners were in use at 69 of America's 453 airports.
Types of Scanners: Both Safe
According to the FDA, two types of scanners are in use at US airports: general-use X-ray security systems and millimeter wave security systems. Both are considered extremely safe. (Reagan National uses millimeter wave technology).
- General use X-ray machines (also called backscatter systems) emit small amounts of X-rays. The FDA says the radiation dose is equivalent to what people are exposed to in 42 minutes of everyday living. Manufacturers say it's one-thousandth of what you would receive from a dental X-ray. According to published reports, Columbia University's Dr. David Brenner, head of the university's center for radiological research, says researchers should conduct more tests to see how the machines affect specific groups who could be more sensitive to radiation. Children and passengers with gene mutations are said to be less able to repair X-ray damage to their DNA. Peter Rez, Professor of Physics, Arizona State University agrees the machines are very safe. He puts the chances of receiving a life-threatening cancer at approximately 1 in 30 million, as long as the machines are working properly and do not jam. No studies have been done to determine how frequent low-dose X-ray exposure in frequent travelers could affect their individual health.
- Millimeter wave machines are either "active," exposing passengers to small amounts of millimeter wave energy; or "passive," which measure natural millimeter wave emissions from the body. The FDA says there are "no known adverse health effects" and that millimeter waves do not appear to cause cancer. However, "chronic exposure to lower frequencies of microwaves in some animal studies have been correlated with accelerated development of existing tumors." **See Footnote
Puffers: Into Thin Air
Remember those puffer machines? Officially, they were called explosive trace portals. TSA spent about $30 million for 207 of the bomb-detecting devices. More than half were never deployed. And now the rest are scrapped. Seems they didn't work that well, broke down frequently, and cost too much to fix.
**Ryan KL, D'Andrea JA, Jauchem JR, Mason PA
(February 2000). "Radio frequency radiation of millimeter wave length: potential occupational safety issues relating to surface heating". Health Physics 78 (2): 170-81. PMID 10647983.
Sharyl Attkisson is a CBS News Investigative Correspondent based in Washington. You can read more of her posts in Hotsheet here.