WASHINGTON—The U.S. Senate will hold an Oct. 26 hearing with tech firms Snap’s Snapchat, TikTok, and Alphabet’s YouTube about their platforms’ impact on young users, a panel said on Tuesday. “Recent revelations about harm to kids online show that Big Tech is facing its Big Tobacco moment—a moment of reckoning,” said Senator Richard Blumenthal, who chairs the Senate Commerce consumer protection subcommittee holding the hearing. “We need to understand the impact of popular platforms like Snapchat, TikTok, and YouTube on children and what companies can do better to keep them safe.” Senator Marcia Blackburn, the top Republican on the subcommittee, said, “TikTok, Snapchat, and YouTube all play a leading role in exposing children to harmful content.” A Snap spokeswoman said the company looks forward to discussing their “approach to protecting the safety, privacy, and wellbeing of our Snapchat community.” TikTok and YouTube both confirmed they would take part. Earlier this …