The Environmental Protection Agency (EPA) is approving a revision to the Missouri State Implementation Plan (SIP) related to municipal solid waste landfills in the St. Louis ozone nonattainment area. The revision to this rule includes incorporating by reference Emission Guidelines (EG) for Municipal Solid Waste (MSW) landfills. EPA is approving this SIP revision based on EPA's finding that the rule implements more stringent thresholds and do not impact the stringency of the SIP or have an adverse effect on air quality. The EPA's approval of this rule revision is being done in accordance with the requirements of the Clean Air Act (CAA).