A proposed US Transportation Security Administration (TSA) security procedure requiring travellers to remove books from their carry on luggage at screening checkpoints has raised privacy concerns from the American Civil Liberties Union (ACLU).

The Hill reports that during a test conducted in May at airports in California and Missouri, the TSA instructed travellers to remove books and papers from their luggage prior to running bags through security scanners.

The bulky nature of such items can make it difficult for TSA agents to view other items. “At times, paper products do set off alarms and procedures call for additional screening,” said TSA acting director of public relations Lisa Farbstein in a press statement.

However, the ACLU contended that the procedure could run afoul of privacy protections. “A person who is reading a book entitled “Overcoming Sexual Abuse” or “Overcoming Sexual Dysfunction” is not likely to want to plop that volume down on the conveyor belt for all to see,” noted Jay Stanley, a senior policy analyst for the  ACLU Speech, Privacy, and Technology Project in a blog post.

“Even someone reading a bestseller like “50 Shades of Grey” or a mild self-help book with a title such as “What Should I Do With My Life?” might be shy about exposing his or her reading habits. And of course someone reading Arab or Muslim literature in today’s environment has all too much cause to worry about discrimination.”

The ACLU urged TSA to train its agents about privacy protections, including “orders curbing any agents’ temptations to snoop through, draw attention to, comment on, or discriminate upon any books and papers they incidentally observe in the screening process,” said Stanley.

Passengers also should have the right to have their papers searched separately in private and to conceal the nature of their literature upon removal from baggage, he said.

Farbstein said that the test involving books and paper had been discontinued.

The TSA has also been experimenting with screening procedures that require travellers to remove all electronics larger than mobile phones from their carry on luggage, and Department of Homeland Security Secretary John Kelly said at least some of the additional security measures being tested are likely to be implemented nationally.