Ohio Rev. Code Ann. § 4117.12
(B) When anyone files a charge with the board alleging that an unfair labor practice has been committed, the board or its designated agent shall investigate the charge. If the board has probable cause for believing that a violation has occurred, the board shall issue a complaint and shall conduct a hearing concerning the charge. The board shall cause the complaint to be served upon the charged party which shall contain a notice of the time at which the hearing on the complaint will be held either before the board, a board member, or an administrative law judge. The board may not issue a notice of hearing based upon any unfair labor practice occurring more than ninety days prior to the filing of the charge with the board, unless the person aggrieved thereby is prevented from filing the charge by reason of service in the armed forces, in which event the ninety-day period shall be computed from the day of the person's discharge. If the board dismisses a complaint as frivolous, it shall assess costs to the complainant pursuant to its standards governing such matters, and for that purpose, the board shall adopt a rule defining the standards by which the board will declare a complaint to be frivolous and the costs that will be assessed accordingly.