Facebook Chief Executive Mark Zuckerberg faced criticism Tuesday from senators over the handling of personal data in a Capitol Hill hearing that has amounted to a reckoning on how technology companies obtain and profit from personal data.

“Let me just cut to the chase. If you and other social media companies do not get your act in order, none of us are going to have any privacy anymore,” Sen. Bill Nelson, D-Fla., told Zuckerberg, who was making his first appearance on Capitol Hill, underscoring the severity of Facebook’s crisis.

Zuckerberg offered contrition for his company’s mishandling of personal information from up to 87 million unsuspecting Facebook users that landed in the hands of Cambridge Analytica, a political consulting firm that worked on the Donald Trump campaign.

Zuckerberg’s opening statement closely mirrored prepared remarks that circulated Monday.

“We didn’t take a broad enough view of our responsibility, and that was a big mistake. It was my mistake, and I’m sorry,” he said.

The billionaire tech executive is also scheduled to appear before the House Energy and Commerce Committee on Wednesday.

The congressional grilling adds to the mounting difficulties at the Menlo Park, Calif., company, which has been on the defense since it downplayed the effect of Russian interference on its platform during the 2016 presidential election.

The Cambridge Analytica scandal has also resulted in a new Federal Trade Commission investigation looking into whether Facebook violated a 2011 consent decree requiring the company to properly inform users about changes to their privacy settings.

The biggest threat to Facebook, however, would be new regulations that challenge the company’s lifeblood: access to increasing amounts of personal data from its 2 billion users.

That’s necessary, Zuckerberg argued, to support Facebook’s ad-supported business model.

“We want to offer a free service anyone can afford,” Zuckerberg said. “It’s the only way we can reach billions of people.”

Rather than wait for regulation, Facebook in recent days has announced a slew of changes aimed at boosting transparency for users and limiting how much data are accessible to outside apps.

Despite pledges by Zuckerberg to increase transparency, Sen. Richard Blumenthal, D-Conn., said Facebook’s business model would always favor data collection over user privacy and security without legislation.

“We’ve seen the apology tours before,” Blumenthal said. “I don’t see how you can change your business model unless there are specific rules of the road.”

Zuckerberg was asked on several occasions why the company did not notify users whose data were harvested by Cambridge Analytica sooner (the company began alerting those affected Monday). Zuckerberg said that was a mistake and Facebook should have disclosed the breach sooner.