Ohio Rev. Code Ann. § 3746.12
(A) Except as provided in division (C) of this section, the director of environmental protection shall issue to a person on behalf of whom a certified professional has submitted to the director an original no further action letter and accompanying verification under division (A) of section 3746.11 of the Revised Code a covenant not to sue for the property that is named in the letter. The director shall not issue a covenant not to sue if an original no further action letter is submitted to him by any person other than the certified professional who prepared the letter or if a copy of the letter is submitted to him. A covenant not to sue shall contain both of the following, as applicable:
(1) A provision releasing the person who undertook the voluntary action from all civil liability to this state to perform additional investigational and remedial activities to address a release of hazardous substances or petroleum when the property has undergone a phase I or a phase II property assessment in compliance with this chapter and rules adopted under it or has been the subject of remedial activities conducted under this chapter and rules adopted under it to address a release of hazardous substances or petroleum and such an assessment or those activities demonstrate or result in compliance with applicable standards, except:
(2) If the voluntary action involves the use of engineering controls that contain and control the release of hazardous substances or petroleum at or from the property in order to comply with applicable standards, all of the following:
(B)
(C) The director shall deny a covenant not to sue as a final action for any of the following reasons: