Ohio Rev. Code § 4903.24
If the public utilities commission finds after investigating that any rate, joint rate, fare, charge, toll, rental, schedule, or classification of service is unjust, unreasonable, insufficient, unjustly discriminatory, unjustly preferential, or in violation of law, or that any service is inadequate or cannot be obtained, the public utility found to be at fault shall pay the expenses incurred by the commission upon such investigation.
All fees, expenses, and costs of, or in connection with, any hearing or investigation may be imposed by the commission upon any party to the record or may be divided among any parties to the record in such proportion as the commission determines.
All fees, expenses, and costs authorized and collected under this section shall be deposited to the credit of the special assessment fund, which is hereby created in the state treasury. Money in the fund shall be used by the commission for the purpose of covering the costs of any investigations or hearings it orders regarding any public utility.
R.C. § 4903.24