Sen. Charles Schumer (D-N.Y.) on Monday urged retailers to drop plans to track shoppers' movements using their cellphones.
The "FootPath technology" uses antennas to detect cellphone signals and can be used to gather data about shoppers' location and store visits.
The technology is already in place in malls throughout the United Kingdom.
Schumer said consumers should have to opt in to allow stores to track their movements.
"I firmly believe that personal cell phones are just that — personal," he wrote in a letter to Path Intelligence, the British company that makes the tracking technology. "If malls and retailers want to tap into your phone to see what your shopping patterns are, they can ask you to do so. It shouldn’t be up to the consumer to turn their cell phone off when they walk into the mail to ensure they aren’t being virtually tailed."
Schumer also expressed concern that a hacker could use the company's data to gather personal information about someone.
"While I understand Path Intelligence claims to scramble unique cell phone identifiers, and not to collect personal information about a shopper including telephone number and name, I am concerned that the information Path Intelligence collects could easily fall into the wrong hands and be used to connect personally identifiable data with a shoppers geophysical location and movements," he wrote.
In a separate letter, Schumer asked Federal Trade Commission Chairman Jon Leibowitz to look into the technology and analyze whether the U.S. needs new legislation to address cellphone tracking.
Path Intelligence's CEO emphasized that the company only collects anonymous data, and said the company requests that stores post signs to notify consumers that their cellphones are being tracked.
"We welcome the debate around privacy as regards to cellphone detection, and would welcome the opportunity to speak directly with Senator Schumer," CEO Sharon Biggar said in an email to The Hill.
She argued that the technology helps traditional retailers compete with online retailers, which are able to track users' buying habits.
"Online retailers do not require you to 'opt-in' to being tracked," she said. "Rather they observe/track behavior from the moment a shopper enters an online website. We are simply seeking to create a level playing field for offline retailers, and believe you can do so whilst simultaneously protecting the privacy of shoppers."