The Environmental Protection Agency (EPA) is proposing to approve State Implementation Plan (SIP) rule revisions submitted by the Illinois Environmental Protection Agency (IEPA or Illinois) on April 13, 2021, and supplemented by a Clean Air Act (CAA) section 110(l) demonstration submitted on October 6, 2022. Illinois requests that EPA approve rule revisions related to control of volatile organic compound (VOC) emissions from aerospace manufacturing and rework facilities into Illinois' SIP. These rule revisions are approvable because they are consistent with the Control Techniques Guidelines (CTG) for Aerospace Manufacturing and Rework Operations published by EPA in 1997, and satisfy the moderate VOC reasonably available control technology (RACT) requirements of CAA section 182(b)(2) for aerospace facilities in the Illinois portion of the St. Louis nonattainment area (Metro-East area) under the 2015 ozone National Ambient Air Quality Standard (NAAQS or standard). The Metro-East area consists of Madison, Monroe, and St. Clair counties in Illinois.