The Environmental Protection Agency (EPA) is finalizing amendments to the new source performance standards for Automobile and Light Duty Truck Surface Coating Operations pursuant to the review required by the Clean Air Act. The EPA determined that revisions to the NSPS were needed to reflect the degree of emission limitation achievable through the application of the best system of emission reduction (BSER). The EPA is therefore finalizing, as proposed, in a new NSPS subpart MMa, revised volatile organic compound (VOC) emission limits for prime coat, guide coat, and topcoat operations for affected facilities that commence construction, modification, or reconstruction after May 18, 2022. In addition, in the new NSPS subpart, the EPA is finalizing the proposed amendments: the addition of work practices to minimize VOC emissions; revision of the plastic parts provision; updates to the capture and control devices and the associated testing and monitoring requirements; revision of the transfer efficiency provisions; new test methods and alternative test methods; revision of the recordkeeping and reporting requirements, including the addition of electronic reporting; removing exemptions for periods of startup, shutdown, and malfunction; and other amendments to harmonize the new NSPS subpart and Automobile and Light Duty Truck Surface Coating National Emission Standards for Hazardous Air Pollutants (NESHAP) requirements. The EPA is also finalizing the proposed electronic reporting requirements in the NSPS subpart MM, applicable to sources that commence construction, reconstruction, or modification after October 5, 1979, and on or before May 18, 2022.