The US Senate Commerce committee on Thursday voted to issue subpoenas to Facebook’s Mark Zuckerberg, Twitter’s Jack Dorsey and Google’s Sundar Pichai, as Congress considers changes to liability protections granted by Section 230 of the Communications Decency Act.

The three tech CEOs would appear before the committee as witnesses, but the date of the hearing hasn’t been determined.

Neither Facebook, Twitter nor Google immediately responded to requests for comment.