The desire to detect contraband at security checkpoints without revealing travellers’ private parts continues to challenge the US Transportation Security Administration (TSA).

Quartz reports that federal documents discuss the privacy risks associated with screening technology that TSA wants to use as part of its Future Lane Experience (FLEx) system at US airports.

The TAC scanner by vendor ThruVision is described as a “people-screening camera that sees any type of item—including metal, plastic, ceramic, gel, liquid, powder and paper—hidden in peoples’ clothing at distances of 3 to 10 metres (10 to 32 feet).

Some screening equipment used by TSA between 2007 and 2013 was removed after the American Civil Liberties Union (ACLU) sued, saying the technology amounted to a  “virtual strip search” that revealed passengers’ genitalia, breasts, and buttocks.

As with the earlier scanners, the issue with the TAC system may be tied to inadequate privacy filters on the images seen by TSA officers, according to Jay Stanley, an ACLU policy analyst.

“The higher the resolution of the screen, the worse it is,” Stanley tells Quartz. “It could be genitalia, it could be a colostomy bag.”

TSA and ThruVision did not respond to requests for comment on the story.

tsa.gov/