EPA is approving a revision to the Ohio State Implementation Plan (SIP) submitted by Ohio on April 11, 2005 to rescind a rule which affected stationary combustion sources located within Priority I regions of the State and new sources regardless of location. The rule revision we are approving here also applies to nitric acid manufacture. We are taking this action at the request of the Ohio Environmental Protection Agency (Ohio EPA) because this rule is no longer the limiting regulation for any oxides of nitrogen (NO<INF>X</INF>) emission units in the State. The rule was originally approved by EPA over 30 years ago and since then has been superseded by a number of more stringent State and Federal regulations. The Ohio NO<INF>X</INF> SIP call rules and Federal emission standards for utility and industrial units all have greater potential for reducing emissions of NO<INF>X</INF> and improving human health than does the State's rescinded rule.