Ohio Rev. Code § 4903.04: Witnesses may be compelled to testify.

If a person disobeys an order of the public utilities commission or a public utilities commissioner, or a subpoena, or if a witness refuses to testify to any matter regarding which he may be lawfully interrogated, the court of common pleas of a county or a judge of such court, on application of a commissioner, shall compel obedience by attachment proceedings for contempt, as in the case of disobedience of the requirements of a subpoena issued from such court or a refusal to testify therein. The commission also shall have the powers vested in notaries public to compel witnesses to testify and to produce books and papers.