Approval and Promulgation of Implementation Plans; State of Missouri

EPA is announcing the partial approval and partial disapproval of revisions to the Restriction of Emission of Sulfur Compounds rule in the Missouri State Implementation Plan (SIP). This Missouri rule establishes general requirements for emissions of sulfur compounds from various source categories and establishes specific emissions requirements for certain named sources. EPA is approving most of the revisions to the rule because the changes involve clarifications, updates, and other improvements to the current rule. This action does not include a portion of the rule that regulates ambient concentrations of sulfur compounds, because this provision is not in the current SIP, and EPA does not directly enforce Missouri's Air Quality Standards. EPA is disapproving Missouri's request to include in the SIP a revision to two source-specific references because the state has not demonstrated that the revisions are protective of the short-term SO<INF>2</INF> National Ambient Air Quality Standard (NAAQS).