In the science-fiction movie "Total Recall," subway commuters passed behind a massive screen where a body scan displayed their walking skeletons to security guards looking for concealed weapons. Arnold Schwarzenegger, a pistol affixed to his hip, touched off one of the alarms, leading to the requisite Hollywood chase.
Today a less-sophisticated but real-life body scanner is in use at some of the nation's largest international airports. The aim is not to nab interplanetary terrorists, but it is allowing security officials to better detect contraband hidden on travelers - everything from jewels to plastic explosives.
Not surprisingly, though, the idea of having someone else look at an X-ray of an individual's anatomy is striking civil libertarians, not to mention some who don't have the physique of a Schwarzenegger, as an invasion of privacy.
While the criticisms are relatively muted for now, they portend what will likely be a growing debate, as more sophisticated scanning devices are put in airports, courthouses, and other public spaces in the future.
"Our major concern is whether ... the airport security guard will someday become Superman - looking at naked bodies just as they now look through our carry-on bags," says Liz Schroeder of the American Civil Liberties Union of southern California. "We're not at that point, yet. But we need to be vigilant."
In fact, the machines now used in six International airports are used solely by US Customs agents seeking to nab smugglers. The $129,000 scanners are never used by ordinary airport personnel for routine passenger security screening, says Jay Ahern, Customs Service Port Director at Los Angeles International Airport (LAX).
In addition to LAX, airports using the machines include New York's JFK, Miami International, Chicago O'Hare, Atlanta Hartsfield, and Houston Intercontinental.
The body scanner uses a narrow, moving beam of low-dosage X-rays (equivalent to less than half-an-hour's exposure to Earth's ordinary "background" radiation) to produce an image of the body's surface and anything hidden along its contours. Internal organs are not exposed.
Though privacy advocates are concerned, the scanners are intended to be an alternative to a pat-down search for incoming travelers who might find a physical search offensive. At LAX, 70 people have been offered a scan since the equipment went into use in October, Mr. Ahern says. Of those, 19 accepted.
Even then, a scan can only be performed after the passenger gives written consent and a Customs supervisor approves the procedure. Although the radiation output is far too low to be considered a health hazard, Customs does not offer scans to women who are, or think they might be, pregnant.
Whatever problems or conflicts await such devices as they become more advanced or widespread, officials say the existing scanners have been a real boon, a cost-effective law enforcement and public relations tool.
"The machine has seized contraband in excess of its [own cost]," says supervisory Customs inspector Vincent DiGilio in New York.
"Since [it] has been in use at JFK, there has not been a single letter of complaint," he says. "It gives people [who know themselves to be innocent] the sense of being in control of what's happening to them."
The procedure, conducted by specially trained Customs personnel of the same sex as the passenger, takes place in an area out of public view.
If something suspicious is found, inspectors can then confirm the findings by physical search. If nothing is found, the image is automatically dumped as a further safeguard of individual privacy.
"It is proper to ask tough questions about technology that might impinge on civil liberties," says Bruce Hoffman, head of terrorism research for the RAND Corp. and director of its Washington office. Yet at locations requiring a high degree of security, future walk-by screening devices might play a useful role, he says. At the Pentagon or federal courthouses, such scanners would be "no different than metal detectors and less intrusive than a pat-down."
Even the critic's "Total Recall" scenario - routine scanning of subway commuters - might have an upside, particularly in light of the potential for enormous loss of life from a single terrorist act in such a densely populated space.
"A metal detector will pick up knives and most guns," says Hoffman. "But if you had plastic explosives and a plastic watch you were going to attach it to, it wouldn't [notice]."
Nevertheless, "the technology is only as good as the human operator," he cautions. "It is no panacea [for] the terrorism threat."
(c) Copyright 2000. The Christian Science Publishing Society