The Environmental Protection Agency (EPA) is disapproving the visibility transport (prong 4) portion of a revision to the Alabama State Implementation Plan (SIP), submitted by the Alabama Department of Environmental Management (ADEM), addressing the Clean Air Act (CAA or Act) infrastructure SIP requirements for the 2008 8-hour ozone National Ambient Air Quality Standards (NAAQS). The CAA requires that each state adopt and submit a SIP for the implementation, maintenance, and enforcement of each NAAQS promulgated by EPA, commonly referred to as an "infrastructure SIP." Here, EPA is specifically disapproving the prong 4 portion of Alabama's August 20, 2012, 2008 8-hour ozone infrastructure SIP submission. All other applicable infrastructure requirements for this SIP submission have been addressed in separate rulemakings.