The latest high-tech security measure, the subject of a legal challenge on privacy grounds, is moving closer to implementation at Minneapolis-St. Paul International Airport.

Sitting at Checkpoint 10 on the skyway level between concourses C and G is an advanced imaging technology scanner, better known as a full-body scanner, which promises to be a better detector of suspicious items and is an alternative to the traditional walk-through metal detector and pat-downs.

The scanner at the Twin Cities airport was installed Monday and should be operating within a few weeks. More of the machines will be up and running at MSP in the fall, said Carrie Harmon, a spokeswoman for the federal Department of Homeland Security.

"The scan itself takes just a few seconds, and the whole process takes about 20 seconds," Harmon said.

The devices were first installed at some U.S. airports in March and are being used at dozens of airports around the country.

The federal Transportation Security Administration (TSA) says that the advanced imaging technology enhances security by detecting both metallic and nonmetallic threat items -- including weapons and explosives -- concealed under layers of clothing.

The new "technology has led to the detection of more than 65 prohibited, illegal or dangerous items at checkpoints nationwide since January of this year," Harmon said.

Technique is optional

Passengers can decline to use the scanner and opt for other screening measures.

"There will be multiple signs at the checkpoint indicating that screening with advanced imaging technology is optional for all passengers," Harmon said. "Passengers who choose not to be [scanned] will receive alternative screening, including a pat-down."

The scanners cost $130,000 to $170,000 and are paid for by economic stimulus money from the federal American Recovery and Reinvestment Act. Funding is available for nearly 1,000 units.

Before entering the scanner, passengers must remove everything from their pockets, not just coins or other metal items, Harmon said.

For anyone nervous about being separated even for a moment from their money, jewelry, passport or other items, Harmon said, "We encourage passengers to put valuables in their carry-on bag before it goes through the X-ray."

Addressing privacy concerns, federal officials say that security agents at the body-scan checkpoints don't see the travelers' images as they are scanned. Another agent, away from the checkpoint, reviews the images and communicates via headset.

The images, which look like a chalk etching, are automatically deleted and cannot be stored, printed, transmitted or saved, according to the TSA.

Privacy concerns raised

A leading legal privacy organization contends that body images of "ordinary Americans" have been saved by the machines at various federal courthouses and the same could be done at airports.

The Washington-based Electronic Privacy Information Center (EPIC) has asked a federal court to suspend the airport program, citing constitutional violations.

"The ability of body scanners to store images ... underscores the need for the court to take action on EPIC's emergency motion," said Ginger McCall, staff counsel for EPIC.

In response, Harmon said, "All advanced imaging technology machines are delivered to airports without the capability to store, print or transmit images. TSA required advanced imaging technology machines to have the capability to retain and export images only for use in the testing mode." That testing, Harmon added, is done at TSA facilities, not at any airport.

Teresa Nelson, legal counsel for the American Civil Liberties Union of Minnesota, said Tuesday that if the new machines are "used as a secondary screening measure where there is legal grounds to do a strip search, then this is a fine alternative, but we oppose subjecting every member of the traveling public to a virtual strip search."

The devices are much more intrusive that the current screening machines and are not necessarily better, Nelson said.

"It doesn't detect explosives or other things hidden in body cavities, and that is something the terrorists have started to do," she said. "Some experts say that it would not have identified the explosives hidden on the body of the Christmas Day bomber. We are giving away substantial privacy for a device that is not necessarily effective."

She said the civil liberties group is pushing nationwide for legislation that would support a ban "on using electronic strip searches as the primary means of screening passengers."

She said the national organization also believes the law should forbid the storage or misuse of the images.

Locally, Nelson said the state civil liberties organization is asking people to notify it if they have complaints once the new screening devices are installed.

Staff writer Randy Furst contributed to this report. Paul Walsh • 612-673-4482