EPA is approving a site-specific revision to the Minnesota sulfur dioxide (SO2) State Implementation Plan (SIP) for the Olmsted Waste to Energy Facility (OWEF), located in Rochester, Olmsted County, Minnesota. In its September 28, 2007, submittal, the Minnesota Pollution Control Agency (MPCA) requested that EPA approve certain conditions contained in OWEF's revised Federally enforceable Title V operating permit into the Minnesota SO2 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 rulemaking action.