cellphone tower dump privacy Federal, state and local law enforcement agencies conducting criminal investigations last year had access to the cellphone data of thousands of Americans not suspected of any crime.

A congressional inquiry revealed that law enforcement officials made more than 9,000 “tower dump” requests for information on all calls bounced off a cellphone tower within a certain time period.

In response to government requests, major carriers have provided information like GPS location data, website addresses and even search terms Americans have entered into their cellphones.

Sen. Edward J. Markey (D-Mass.) led the inquiry and is planning to introduce legislation this month to restrict law enforcement’s use of consumer phone data and ensure tower dumps are narrowly focused.

Privacy advocates say collecting tower data on law-abiding citizens in order to find clues about a small number of suspects raises concerns similar to the NSA’s mass collection of phone records without a warrant. But unlike NSA data collection, which requires court oversight, the standards for obtaining and using tower data remain unclear.

“This isn’t the NSA asking for information,” Markey told the Washing Post. “It’s your neighborhood police department requesting your mobile phone data. So there are serious questions about how law enforcement handles the information of innocent people swept up in these digital dragnets.”