The Environmental Protection Agency (EPA) is taking direct final action to approve an update to a portion of the Outer Continental Shelf (OCS) Air Regulations for Maryland. Requirements applying to OCS sources located within 25 miles of States' seaward boundaries must be updated periodically to remain consistent with the requirements of the corresponding onshore area (COA), as mandated by the Clean Air Act, as amended in 1990 (CAA or the Act). The portion of the OCS air regulations that is being updated pertains to the requirements for OCS sources for which Maryland is the designated COA. The intended effect of approving the OCS requirements for the Maryland Department of the Environment is to regulate emissions from OCS sources in accordance with the requirements onshore.