Approval of Missouri Air Quality Implementation Plans; Infrastructure SIP Requirements for the 2010 Sulfur Dioxide National Ambient Air Quality Standard; Withdrawal of Direct Final Rule

Due to adverse comments, the Environmental Protection Agency (EPA) is withdrawing the direct final rule for ``Approval of Missouri Air Quality Implementation Plans; Infrastructure SIP Requirements for the 2010 Sulfur Dioxide National Ambient Air Quality Standard'' published in the Federal Register on October 6, 2017. The direct final rule was an approval of a State Implementation Plan (SIP) revision from the State of Missouri for the 2010 Sulfur Dioxide (SO 2 ) National Ambient Air Quality Standard (NAAQS). Section 110 of the CAA requires that each state adopt and submit a SIP for the implementation, maintenance, and enforcement of each new or revised NAAQS promulgated by EPA. These SIPs are commonly referred to as ``infrastructure'' SIPs. The infrastructure requirements are designed to ensure that the structural components of each state's air quality management program are adequate to meet the state's responsibilities under the CAA.