Ohio Rev. Code Ann. § 3933.02

No person shall be excused from attending, testifying, or producing any books, papers, or other documents before any court or magistrate having jurisdiction, upon any investigation, proceeding, or trial for a violation of any of sections 3933.01 to 3933.03, inclusive, of the Revised Code, upon the ground that the testimony of evidence, documentary or otherwise, required of him may tend to incriminate or degrade him. No person shall be prosecuted or subject to any penalty or forfeiture on account of any transaction, matter, or thing concerning which he may so testify or produce evidence, documentary or otherwise, except for perjury committed in so testifying.