Meta has been accused of putting growth and profits ahead of child safety, with a former senior employee telling a landmark US trial that the social media giant operated a “don’t ask, don’t tell” approach to underage users.

In Northern California on Tuesday, a jury heard opening statements in the federal trial over whether Meta deliberately designed Facebook and Instagram to attract and retain young users despite knowing about potential harms like addictive features and their risks to mental health..

Arturo Béjar, a former Meta engineering director who worked at the company from 2009 to 2015 and later returned as a contractor, gave evidence in a federal court in Oakland. 

Béjar told the court that safety concerns raised internally were repeatedly ignored and that Meta did little to identify children under 13 using its platforms. He alleged that the company’s culture placed greater emphasis on user engagement and growth than protecting young users.

His evidence forms part of a case led by California, Colorado, Kentucky and New Jersey. The states are alleging that Meta’s platforms were designed to maximise engagement among children and teenagers, meanwhile the company misled the public about the risks.

The states’ lawyers opened the trial by portraying Meta’s strategy as “hook, harvest, hide”. They alleged that the company sought to hook young users, harvest their data and conceal what it knew about the potential consequences.

They also allege Meta violated federal child privacy laws by collecting and using data from children under 13 without appropriate parental consent. The wider case accuses the company of contributing to a youth mental-health crisis through addictive features designed to encourage prolonged use.

Béjar claimed age verification was deliberately limited because identifying and removing underage users could reduce engagement. He also criticised safety features, including Instagram’s “Take a Break” function, arguing that they are ineffective in that users must activate it themselves. 

The former executive described his personal reason for raising the issue with his own daughter having received disturbing Instagram messages, which reinforced the concerns he had already raised internally.

Béjar said he had numerous interactions with Meta chief executive Mark Zuckerberg and that significant safety changes generally required Zuckerberg’s direct involvement. Reuters reported that Béjar testified Zuckerberg’s focus on growth and engagement influenced the company’s culture and its approaches to safety.

The states are seeking financial penalties and changes to the way Facebook and Instagram operate. Estimates of potential damages have ranged from about US$200 billion to as much as US$1.4 trillion, depending on the outcome.

Meta has rejected the allegations, arguing that it does not deliberately seek to addict children and that it has invested heavily in safety measures. The company says its platforms prohibit users under 13 and maintains that it has tools designed to protect young people.

The trial is expected to last six to eight weeks. Zuckerberg and Instagram chief Adam Mosseri are expected to testify.