Ohio Rev. Code Ann. § 3704.011
(A) In addition to any other exemption provided in this chapter or rules adopted under it, an air contaminant source is exempt from this chapter and rules adopted under it if the emissions of particulate matter, nitrogen oxides, organic compounds, sulfur dioxide, carbon monoxide, lead, or any other air contaminant from that source do not exceed ten pounds per day, as verified in accordance with division (C) of this section, provided that the exemption does not apply to any air contaminant source if any of the following applies:
(B)