USEPA is approving a redesignation request and maintenance plan for Preble, Columbiana, and Jefferson County, Ohio as a revision to Ohio's State Implementation Plan (SIP) for ozone. The revision is based on a request from the State of Ohio to redesignate these areas, and approve their maintenance plans, and on the supporting data the State submitted. Under the Clean Air Act, designations can be changed if sufficient data are available to warrant such change.