WASHINGTON — Just a week after announcing it had reached 500 million users, Facebook defended its privacy controls amid concerns that it was selling private information to third parties without their consent.

“Facebook never sells data to third parties or advertisers,” the company’s chief technology officer, Bret Taylor, told members of Congress on Tuesday.

Appearing before a Senate committee, along with Apple, Google and AT&T, Facebook officials emphasized their commitment to maintaining the privacy of consumer information. This comes on the heels of Google’s acknowledgment two months ago that it unknowingly collected data on users of its Google Maps Street View program. It’s possible other social networking sites may be compromised as well.

“Everyone at Facebook works on security and design,” Taylor said. “In every aspect of a product’s design, privacy is an aspect of the discussion.”

With more than 130 million users in the United States alone, Taylor’s assertion that everyone at Facebook is involved with privacy rang hollow with Sen. Jay Rockefeller, D-W.Va.

“Saying everybody is [responsible for privacy] is suspicious and disingenuous, and I don’t believe it,” Rockefeller said. “Always lurking is the record — you’re being tracked, and people are using you to advertise. The philosophical question is: Are we dividing ourselves into two classes of people? People who understand [the online world] and those who cannot, and those who cannot are paying a price. Can I really stop Facebook from having records on me? You say yes; I say I’m not so sure.”

Taylor tried to assure the senator that Facebook can be trusted.

“We’ve tried to take a very proactive approach with privacy,” Taylor said. “We try to make it easy to enable people to change privacy settings. Ads are only targeted to information in your profile, but if you remove that information, you’ll no longer be targeted.”

Facebook recently announced it is testing a feature that will allow users to easily delete their accounts. Sen. John Kerry, D-Mass., brought up concerns about Facebook’s information-saving policies and whether deletion of information from a personal account really is deletion, or just stored on a Facebook server.

“Is it true that you only modify your practices after concern has been raised by your consumers?” asked Kerry.

Taylor gave a complex answer that involved how other users keep information on Facebook. Taylor said while that information may be gone from your personal online profile if you delete it, it may also be stored on another person’s profile.

“When you’re sharing information with other human beings on the Internet, you know, it’s not just a technical thing, it’s a social thing and people may choose to do things with that information outside of the bounds of the things that we can control,” Taylor said. “There may be backups of some pieces of information somewhere.”

In response to safety concerns, Facebook unveiled a safety page Monday intended to complement its safety center. As of Tuesday, more than 2.2 million people had linked to the new safety page.