The first airport 3-D body screening machine was tested at Phoenix Sky Harbor International yesterday. The new tool in U.S. airports’ security arsenal is taking a 3-D image of passengers using radio waves to check for explosives, metal, plastic and liquids - anything hidden on the body. The machines are being used by the Transportation Security Administration (TSA) as an alternative to physically patting down some passengers at the security checkpoints. The American Civil Liberties Union has objected to the technology, concerned that the machines are capable of showing passengers’ bodily parts. TSA says the images look more like an x-ray and blurred photo negative keeping passengers’ privacy.

The new airport security equipment will also be tested at New York’s Kennedy and Los Angeles International airports, officials confirmed.