Welcome to Law.com Class Actions: Critical Mass, a weekly briefing for class action and mass tort attorneys.

This week: A federal judge ruled that school districts could pursue public nuisance claims against social media sites Instagram, TikTok and others. A Johnson & Johnson subsidiary in the third talc bankruptcy filed a sanctions motion against Beasley Allen’s Andy Birchfield after he failed to show up for a Monday deposition. W. Mark Lanier and Ben Crump teamed up to represent this family over a factory explosion this month.