The company got the information while photographing neighborhoods for its "Street View" mapping feature. Google said it was trying to gather information about the location, strength and configuration of Wi-Fi networks so it could improve the accuracy of location-based services such as Google Maps and driving directions. Going further and collecting snippets of information traveling over those networks "was a mistake," Pablo Chavez, Google's director of public policy, wrote in the letter.
Google's letter, released Friday, was a response to an inquiry by Rep. Joe Barton of Texas, the top Republican on the House Energy and Commerce Committee, and Massachusetts Democrat Edward Markey, a key member of the Subcommittee on Communications, Technology and the Internet. The letter was addressed to Barton, Markey and Commerce Committee Chairman Henry Waxman, D-Calif.
House Judiciary Chairman John Conyers, D-Mich., has also expressed concern about Google's actions.
Although the company used its Street View cars as a platform for the Wi-Fi equipment, the Street View photographs and the collection of Wi-Fi network information are separate efforts. Google says it has stopped grabbing Wi-Fi data from its Street View vehicles since it discovered the data collection problem last month following an inquiry by German regulators.
In the letter sent to the House, Google said that any personal information inadvertently swept up in the process of mapping Wi-Fi networks was "not used to identify any specific individual or household" and was stored only in "raw, aggregate, binary form." It added that "the payload data has never been used in any Google product or service, nor do we intend to use it."
The company also said it is aware of only two Google engineers who have even seen the data: the engineer who designed the software used to process information about the Wi-Fi networks being mapped, and the engineer who tested the data that had been collected after the company learned of the problem.
For now, Google is retaining the data collected in the United States to comply with a court order stemming from pending civil litigation. The company has deleted data that came from Ireland, Denmark and Austria at the request of authorities in those countries.
Google's explanations did not do enough to appease Barton and Markey, who have called on the Federal Trade Commission to investigate the company's actions.
"Google now confesses it has been collecting people's information for years, yet claims they still do not know exactly what they collected and who was vulnerable," Barton said in a statement. "This is deeply troubling for a company that bases its business model on gathering consumer data."