The USEPA is approving, as revisions to the ozone portion of the Ohio State Implementation Plan (SIP), through direct final procedure, Ohio's 1990 base-year ozone precursor emissions inventory for the Toledo and Dayton ozone nonattainment areas. These emissions inventories were submitted to satisfy a Federal requirement that States containing ozone nonattainment areas submit inventories of actual ozone precursor emissions for the year 1990. The Ohio ozone nonattainment areas covered by this rulemaking are Toledo (Lucas and Wood Counties) and Dayton (Clark, Greene, Miami, and Montgomery Counties).