The Environmental Protection Agency (EPA or Agency) is taking final action to approve a revision to Montana's State Implementation Plan (SIP). On July 6, 2016, the Governor of Montana submitted to EPA a revision to the Montana SIP that removed one section of the Administrative Rules of Montana (ARM) pertaining to aluminum plants. In this document, EPA is finalizing approval of the removal of this section from the SIP. EPA determined the provision was inconsistent with Clean Air Act (CAA) requirements and EPA issued a SIP call for the State to revise the provision on June 12, 2015. Removal of this provision corrects the deficiencies identified in 2015 related to the treatment of excess emissions from aluminum plants and fully satisfies the SIP call issued to Montana.