Meta has settled a major lawsuit with many US states.

The states said that Meta's platforms harm children's mental health.

The deal was announced on Wednesday.

It ends a trial in California.

Meta will pay up to $18 billion.

The deal also includes new safety measures for young users on Instagram and Facebook.

The settlement involved four states as plaintiffs.

They are California, Colorado, Kentucky, and New Jersey.

It also resolved a separate trial in Tennessee.

Tennessee Attorney General Jonathan Skrmetti said the deal provides "unprecedented protections" for kids.

He also said it gives record-setting money to the state's Children's Digital Protection Fund.

Two states did not join the settlement.

New Mexico had already won its own case against Meta.

In that case, a judge ordered the company to pay $567 million in August.

Florida's attorney general said the settlement was not tough enough on Meta.

Separately, hundreds of US school districts have sued social media companies.

They want money for costs related to children's mental health.

A Kentucky school district case settled before trial this summer.

In another first-of-its-kind case, a jury found Meta and YouTube liable for social media addiction.

The jury awarded $6 million in damages.

Both companies have appealed.