ShareThisAs the federal government begins an inside-out review of airport security after a passenger allegedly sneaked explosives onto a plane last week, attention is turning to a growing debate over a key approach to airline safety: whole-body imaging at airports.
Critics say the technique compromises privacy by letting screeners "peer through clothing and capture detailed, three-dimensional images of individuals completely undressed," according to a recent lawsuit.
But supporters are adamant that the imaging protects privacy while making flying safer.
In the 19 U.S. airports that use this screening method, passengers enter what looks like a clear phone booth and pause while a body photo is taken that's about as distinct as a "fuzzy photo negative," says the Transportation Security Administration.
Unlike a metal detector -- which is easily set off by implants such as metal knees and hips -- a whole-body image shows only anomalies outside the body.
"What it shows is dark spots. Whole-body imaging can tell if you have plastic or powders or anything that would cause harm to an aircraft if you have it taped to your body," said a TSA official authorized to speak only on background.
Security experts say the technology would likely have snared 23-year-old Umar Farouk Abdulmutallab of Nigeria before he boarded a Detroit-bound airliner from Amsterdam on Christmas, allegedly with explosive powder strapped to his leg.
As the plane approached its destination, authorities say, Abdulmutallab used a syringe of chemicals to try to ignite the powder, which failed to detonate but alerted fellow passengers with popping sounds.
Abdulmutallab has been charged with trying to blow up the plane.
Critics say problems with whole-body imaging outweigh its benefits.
In June, the House of Representatives approved a bill to limit its use for airline screening. The bill, introduced by Rep. Jason Chaffetz, R-Utah, would prohibit such images unless a metal detector first indicated a need for more screening. The bill has moved to the Senate.
While 13 of the airports with whole-body imaging use it in place of pat downs, six airports offer it as a primary screening method, although passengers may choose not to go through it --San Francisco, Salt Lake City, Las Vegas, Miami, Albuquerque and Tulsa, Okla.
On Dec. 17, the Electronic Privacy Information Center advocacy group in Washington sued the Justice Department, seeking copies of images taken at airports with the technology, as well as records of any security breaches that might have occurred during use of the screening technique.
The suit claims images are taken of "individuals completely undressed." The group refers to "digital strip searches" on its Web site and says the screening devices "capture images of individuals stripped naked."
Not true, claims the TSA's Web site. It says its machines obscure all faces, and that the screening officer who helps the passenger through the process never sees the image.
Instead, an officer at a remote location who never sees the passenger examines the image.
"The two officers communicate via wireless headset," explains the TSA site. "Once the remotely located officer determines threat items are not present," the passenger can leave, and the image is automatically deleted.
Two whole-body imaging technologies are available: millimeter wave and backscatter.
Millimeter wave technology beams high-frequency radio waves from two antennae rotating around the body to produce what looks like a photonegative. The energy produced "is 10,000 times less than a cell phone transmission," the TSA site says.
Backscatter technology uses a low-level X-ray equivalent to what you get during two minutes of flight time and produces "an image that resembles a chalk etching."
Contact Nanette Asimov at nasimov(at)sfchronicle.com. For more stories visit scrippsnews.com
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