The Environmental Protection Agency (EPA) is approving South Carolina's June 25, 2018, State Implementation Plan (SIP) submission pertaining to the "good neighbor" provision of the Clean Air Act (CAA or Act) for the 2010 1-hour sulfur dioxide (SO<INF>2</INF>) National Ambient Air Quality Standard (NAAQS). The good neighbor provision requires each state's implementation plan to address the interstate transport of air pollution in amounts that contribute significantly to nonattainment, or interfere with maintenance, of a NAAQS in any other state. In this action, EPA has determined that South Carolina's SIP contains adequate provisions to prohibit emissions within the State from contributing significantly to nonattainment or interfering with maintenance of the 2010 1-hour SO<INF>2</INF> NAAQS in any other state.