EPA is approving a revision to the maintenance plan for the Ohio portion of the Cincinnati-Hamilton, OH-KY-IN 8-hour ozone area. The Cincinnati-Hamilton area includes Butler, Clermont, Clinton, Hamilton, and Warren Counties in Ohio, Lawrenceburg Township in Dearborn County, Indiana, and Boone, Campbell, and Kenton Counties in Kentucky. The Ohio Environmental Protection Agency (Ohio EPA) submitted a maintenance plan revision on July 6, 2010. The submittal contained revisions to 2015 and 2020 NO<INF>X</INF> point source emissions projections for Butler County to reflect modifications at a major source that will occur during the maintenance period.