EPA is approving a request submitted by the Minnesota Pollution Control Agency (MPCA) on June 16, 2010, to revise the Minnesota State Implementation Plan (SIP) for carbon monoxide (CO) under the Clean Air Act (CAA). The State has submitted a limited maintenance plan for CO showing continued attainment of the CO National Ambient Air Quality Standard (NAAQS) in the Minneapolis-St. Paul (Twin Cities) area. The one hour CO NAAQS and eight hour CO NAAQS are 35 parts per million (ppm), and 9 ppm, respectively. This limited maintenance plan satisfies section 175A of the CAA, and is in accordance with EPA's October 29, 1999, approval of the State's redesignation request and maintenance plan for the Twin Cities area. Additionally, this limited maintenance plan for CO satisfies the requirements contained in the October 6, 1995, EPA memorandum entitled "Limited Maintenance Plan Option for Nonclassifiable CO Nonattainment Areas."