The Environmental Protection Agency is approving a site- specific revision to the Minnesota Sulfur Dioxide (SO<INF>2</INF>) State Implementation Plan (SIP) for the Northern States Power Company (NSP) Riverside Plant. By its submittal dated September 1, 1999, the Minnesota Pollution Control Agency (MPCA) requested that EPA approve NSP Riverside's Title V Operating Permit into the Minnesota SO<INF>2</INF> SIP and remove the NSP Riverside Administrative Order from the state SO<INF>2</INF> SIP. The request is approvable because it satisfies the requirements of the Clean Air Act (Act). The rationale for the approval and other information are provided in this notice.