Reps. Joe Barton (R-Texas) and Edward Markey (D-Mass.) on Wednesday called for the Federal Trade Commission to investigate Facebook's practice of tracking users even after they log out of its site.
Facebook admitted this week that it collects data when users visit websites that feature its "Like" button, even when the users have logged out of their Facebook accounts. A Facebook spokesman said the data collection is inadvertent, and that the company does not use or store the information.
The lawmakers also criticized Facebook for not acting quickly enough to stop the practice. In a Wall Street Journal story Monday, a Facebook engineer said it would "take a while" to correct the problem.
"Facebook should consider this problem a top priority and should allocate the resources necessary to safeguard consumers in an expedited fashion," Barton and Markey wrote.
The lawmakers argue that tracking users after they log out of Facebook would fall under the FTC's authority to investigate "unfair and deceptive acts or practices."
Barton and Markey are the co-chairmen of the Congressional Bi-Partisan Privacy Caucus.
A Facebook spokesman said there was no security or privacy breach.
"Like every site on the internet that personalizes content and tries to provide a secure experience for users, we place cookies on the computer of the user. Three of these cookies on some users' computers inadvertently included unique identifiers when the user had logged out of Facebook. However, we did not store these identifiers for logged out users. Therefore, we could not have used this information for tracking or any other purpose. Even though we weren't using this information, it's important to us that we address even potential issues, and we appreciate the issue was brought to our attention," he said.