The Environmental Protection Agency (EPA) is approving portions of a State Implementation Plan (SIP) revision submitted by the State of South Carolina, through the South Carolina Department of Health and Environmental Control (SC DHEC), on September 5, 2017, that seek to revise certain New Source Review (NSR) regulations regarding the Prevention of Significant Deterioration (PSD) permitting program. EPA is finalizing this action pursuant to the Clean Air Act (CAA or Act).