Air Plan Partial Approval and Partial Disapproval; Missouri; Construction Permits Required

The Environmental Protection Agency (EPA) is taking final action to partially approve and partially disapprove revisions to the Missouri State Implementation Plan (SIP) received on March 20, 2019 and June 10, 2021. The SIP revisions in the 2019 and 2021 submittals incorporate updates to construction permit requirement regulations for stationary and portable air sources in Missouri that help ensure ambient air quality standards are met. The changes include procedures for the Missouri Department of Natural Resources (MoDNR) to issue general permits, numerous organizational changes, administrative and typographical edits. The approved portions of the rule revision meet the requirements of the Clean Air Act. EPA is disapproving Section (1)(B) regarding voluntary permits. EPA is disapproving because the language of the provision is too vague and does not provide sufficient clarity for implementation.