The Environmental Protection Agency (EPA) is taking final action to approve revisions to the Missouri State Implementation Plan (SIP) received on November 29, 2016, and March 7, 2019. The revisions were submitted by Missouri in response to a finding of substantial inadequacy and SIP call published on June 12, 2015, for a provision in the Missouri SIP related to excess emissions during startup, shutdown, and malfunction (SSM) events. In the submissions, Missouri requests to revise a regulation related to restriction of emissions of visible air contaminants.