WASHINGTON -- The Transportation Security Administration plans to expand its use of screening machines that look under passengers' clothing for hidden weapons.
Los Angeles International and New York's Kennedy airports will get "backscatter" X-ray machines, which the American Civil Liberties Union has called a "virtual strip search" for the vivid anatomical images they can create. Those airports and Phoenix Sky Harbor also will test a similar technology, using low-intensity millimeter waves, to scan passengers' bodies.
The machines are capable of showing passengers' bodily parts, but the TSA says that, because privacy concerns, they will not. All of the machines will use software that will blur images of passengers, so screeners will see weapons but only fuzzy images of people's bodies.
Their use will be voluntary for passengers who are pulled aside for extra screening beyond a metal detector.
"We will not roll out body imaging that does not have very high standards of privacy protection," TSA Administrator Kip Hawley said in an interview. "We'll use a variety of measures including software that may obscure some features."
The expansion of the body-imaging program follows a test at Phoenix of the first X-ray machine at a U.S. airport checkpoint. Since the TSA installed the machine in February, 79% of passengers have chosen to be scanned by the X-ray machine instead of being patted down by a screener, the agency said.
The Phoenix X-ray machine generates cartoon-like images of passengers, using a "privacy algorithm," the TSA said. Screeners can easily see metal objects. The machines emit small amounts of radiation, according to federal research.
Barry Steinhardt, head of the ACLU's technology program, said privacy filters make body imagers "useless as a security device" because blurring can make it difficult for screeners to see weapons.
"There is a trade-off between revealing images, which might show contraband and weapons, and the 'blob machine,' which misses many things," Steinhardt said.
Bruce Schneier, an author and security technology expert in Minnesota, said the machines strike an "excellent" balance between privacy and security. "The issue we're worried about is whether they save the images," Schneier said.
The millimeter-wave machine, made by L-3 Communications, is used at Amsterdam's Schiphol airport and will start operation in Phoenix this month. The additional X-ray machines will start in coming months.
Although both machines will be used only on passengers getting secondary screening, millimeter-wave technology could replace metal detectors because it can scan passengers in a few seconds. X-ray machine scans take about a minute.