A former Facebook employee who has accused the company of putting profit over safety will take her damning accusations to Washington on Tuesday when she testifies to US senators.

Frances Haugen, 37, came forward on Sunday as the whistleblower behind a series of damaging reports in the Wall Street Journal that have heaped further political pressure on the tech giant. Haugen told the news program 60 Minutes that Facebook’s priority was making money over doing what was good for the public.

“The thing I saw at Facebook over and over again was there were conflicts of interest between what was good for the public and what was good for Facebook. And Facebook, over and over again, chose to optimise for its own interests, like making more money,” she said.

Haugen is expected to tell lawmakers that Facebook faces little oversight, and will urge Congress to take action. “As long as Facebook is operating in the dark, it is accountable to no one. And it will continue to make choices that go against the common good,” she wrote in her written testimony.

Haugen was called to testify before the US Senate’s commerce subcommittee on the risks the company’s products pose to children. Lawmakers called the hearing in response to a Wall Street Journal story based on Haugen’s documents that showed Facebook was aware of the damage its Instagram app was causing to teen mental health and wellbeing. One survey in the leaked research estimated that 30% of teenage girls felt Instagram made dissatisfaction with their body worse.

She is expected to compare Facebook to big big tobacco, which resisted telling the public that smoking damaged consumers’ health. “When we realized tobacco companies were hiding the harms it caused, the government took action. When we figured out cars were safer with seatbelts, the government took action,” Haugen wrote. “I implore you to do the same here.”

Haugen will argue that Facebook’s closed design means it has no oversight, even from its own oversight board, a regulatory group that was formed in 2020 to make decisions independent of Facebook’s corporate leadership.

“This inability to see into the actual systems of Facebook and confirm that Facebook’s systems work like they say is like the Department of Transportation regulating cars by watching them drive down the highway,” she wrote in her testimony. “Imagine if no regulator could ride in a car, pump up its wheels, crash test a car, or even know that seatbelts could exist.”

Senator Richard Blumenthal, the Democrat whose committee is holding Tuesday’s hearing, told the Washington Post’s Technology 2020 newsletter that lawmakers will also ask Haugen about her remarks on the 2020 presidential election.

Haugen alleged on 60 Minutes that following Joe Biden’s win in the election, Facebook prematurely reinstated old algorithms that valued engagement over all else, a move that she said contributed to the 6 January attack on the Capitol.

“As soon as the election was over, they turned them back off or they changed the settings back to what they were before, to prioritize growth over safety. And that really feels like a betrayal of democracy to me,” she said.

Following the election, Facebook also disbanded its civic team integrity team, a group that worked on issues related to political elections worldwide and which Haugen worked on. Facebook has said the team’s functions were distributed across the company.

Haugen joined Facebook in 2019 as a product manager on the civic integrity team after spending more than a decade working in the tech industry, including at Pinterest and Google.

Tuesday’s hearing is the second in mere weeks to focus on Facebook’s impact on children. Last week, lawmakers grilled Antigone Davis, Facebook’s global head of safety, and accused the company of “routinely” putting growth above children’s safety.

Facebook has aggressively contested the accusations.

On Friday, the company’s vice-president of policy and public affairs, Nick Clegg, wrote to Facebook employees ahead of Haugen’s public appearance. “Social media has had a big impact on society in recent years, and Facebook is often a place where much of this debate plays out,” he said. “But what evidence there is simply does not support the idea that Facebook, or social media more generally, is the primary cause of polarization.”

On Monday, Facebook asked a federal judge throw out a revised anitrust lawsuit brought by the Federal Trade Commission (FTC) that seeks to force the company giant to sell Instagram and WhatsApp.