We are approving a supplemental revision to the Minnesota State Implementation Plan (SIP) for the Saint Paul particulate matter (PM) nonattainment area, located in Ramsey County, Minnesota. The Minnesota Pollution Control Agency (MPCA) submitted the supplemental SIP for the purpose of maintaining the attainment of the PM National Ambient Air Quality Standards (NAAQS) and is in response to our July 22, 1997 conditional approval (62 FR 39120), of the State's February 9, 1996 SIP revision for Red Rock Road. We are also taking action to revoke the Administrative Order for the Lafarge Corporation that we had approved into the SIP in our July 22, 1997 conditional approval. We are providing the rationale for the approval and other information in this notice.