The Environmental Protection Agency (EPA) is approving a revision to the State of Maryland's state implementation plan (SIP). Maryland requested that EPA incorporate by reference into the Maryland SIP a Maryland Department of the Environment (MDE) order establishing an alternative volatile organic compound (VOC) emission standard for National Gypsum Company (NGC) that will ensure that this source remains a minor stationary source of VOCs. EPA is approving the SIP submittal incorporating by reference MDE's order for NGC in accordance with the requirements of the Clean Air Act (CAA).