The requests from Franken and Illinois Attorney General Lisa Madigan follow recent reports that Google and Apple have been collecting data about the location of Android and iPhone users without their permission. While both companies ask permission before collecting the location data required for certain applications, the reports, starting with one in the Wall Street Journal, show the companies also collect location information when not required to do so by an application.
Madigan said she has asked the companies to explain what information they store, for how long and what it's used for. "I want to know whether consumers have been informed of what is being tracked and stored by Apple and Google and whether those tracking and storage features can be disabled," she said in a statement.
Franken on Monday asked representatives from Google and Apple to attend a hearing on 10 May about protecting mobile privacy.
The lawmakers aren't the only ones concerned about the data collection. Two consumers filed a lawsuit in Florida on Friday, that charges Apple with fraud over the alleged data collection. South Korea and some countries in Europe have also reportedly launched investigations.
In addition, Congressman Edward Markey, a Democrat from Massachusetts, said he wrote to Apple's CEO last week with questions about the company's data collection practices.
Apple has not commented on the matter and did not reply to a request for comment for this story.
Google says it does not collect location information without user permission.
"All location sharing on Android is opt-in by the user," the company said in a statement. "We provide users with notice and control over the collection, sharing and use of location in order to provide a better mobile experience on Android devices. Any location data that is sent back to Google location servers is anonymised and is not tied or traceable to a specific user."