HUMAN NATURE

Naked Came The Passenger

By William Saletan
Sunday, March 4, 2007

Psssst. Want to see Susan Hallowell naked? Look at the Feb. 24 New York Times. She's on page A10.

Hallowell runs the Transportation Security Administration's research lab. Four years ago, she volunteered to be scanned by a backscatter X-ray machine, which sees through clothing. She was wearing a skirt and a blazer. But in the picture, she's as good as naked.

Last week, TSA began using backscatters to screen airline passengers for weapons. The first machine is up and running in Phoenix. The next ones will be in New York and Los Angeles. The machines have been modified with a "privacy algorithm" to clean up what they show. But even the more cartoon-like images they now display tell you more than you need to know about the people seated next to you.

Are you up for this? Are you ready to get naked for your country?

This is no joke. The government needs to look under your clothes. Ceramic knives, plastic guns and liquid explosives have made metal detectors obsolete. Carry-on bags are X-rayed, so the safest place to hide a weapon is on your body. Puffer machines can detect explosives, but only if you're sloppy. Backscatters are different. They can scan your whole surface, locating and identifying anything of unusual density -- not just metals, which have high atomic numbers, but drugs and explosives, which have low ones.

Why isn't this technology in lots of airports already? One reason is fear of radiation. That's a needless worry. You get less radiation from a scan than from sitting on a plane for two minutes. If that's too much for you, don't fly.

The main stumbling block has been privacy. The American Civil Liberties Union and the Electronic Privacy Information Center have fought backscatters, calling them a "virtual strip search." But the purpose of a strip search is the search. Stripping is just a means. Virtual inspections achieve the same end by other means. They don't extend the practice of strip-searching. They abolish it.

When American Science and Engineering, which makes the backscatter machines, introduced the technology in prisons nine years ago, the point was to replace strip searches. "The scan requires no physical contact between the operator and the subject, thus vastly reducing the threat of assault against law enforcement personnel and the spread of communicable diseases," the company argued. The rationale, like the machine, conveyed not an ounce of human warmth. The inmates preferred to be seen rather than touched. Better to be depersonalized than degraded.

Because of terrorism, the rest of us now face the same choice. Under TSA policy, if you set off an airport metal detector or are chosen for secondary screening, you're subject to a pat-down inspection that "may include sensitive areas of the body," such as your chest and thighs. Unless, that is, you're lucky enough to be in Phoenix, where you can choose a backscatter instead.

The impersonality of machines can also filter out racism. Five years ago, the ACLU objected to body scans because they were administered selectively, "based on profiles that are racially discriminatory." But the best way to remove selection bias would be to scan everyone. In Phoenix, the TSA has put the backscatter monitors in a room 50 feet from the security checkpoint, so the officers who staff them can't see you. All they can see are X-ray images, which capture density, not pigment.

The key to reconciling airport security with privacy is that the officer who sees you on the monitor never sees you in the flesh -- never sees your face, never knows who you are. In Phoenix, the TSA hasn't just put the monitors in a separate room. It's laying cables to put them in an entirely different terminal. Likewise, the officer who sees you in the flesh never sees you on the monitor. It's like the blind men and the elephant: Nobody has the whole picture.

That brings us back to Susan Hallowell. The Times did not name the naked woman in its Feb. 24 photo. It did, however, mention that the machines were made by ASE. On the company's Web site, I found a news release complaining that pictures circulating in the media were obsolete, because they had been taken in 2003. Then I ran across a 2004 article that said Hallowell had demonstrated the technology the previous year. I typed her name into a search engine, and up came a 2003 wire story with a photo of her, fully clothed, next to a monitor showing her essentially naked except for a bomb and gun she had hidden under outfit. It is the same image that appeared in the Times.

Hallowell volunteered for this publicity. But this sort of easy identification is exactly what must not happen to others. In the age of body scans, privacy means keeping your name, your face and your nude image apart. That job doesn't end at the security gate; it begins there. Will your scan leak? "Images will not be printed, stored or transmitted," TSA swears on its Web site. Directly above that assurance, the agency has posted four nude pictures -- "actual images shown to the Transportation Security Officer during the backscatter process." And you thought airport screeners had no sense of humor.

Enough with the fairy tales. We lost our innocence when the planes hit the twin towers. Now we're losing our modesty. If we're going to be ogled, at least protect us from being Googled.

human@slate.com

William Saletan covers science and technology for Slate, the online magazine at www.slate.com.


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