Ohio Rev. Code Ann. § 4903.03

The public utilities commission may, through the public utilities commissioners or by inspectors or employees authorized by it, examine all books, contracts, records, documents, and papers of any public utility, and by subpoena duces tecum may compel the production thereof, or of verified copies of the same or any of them. The commission may compel the attendance of such witnesses as it requires to give evidence at such examination.