The Environmental Protection Agency (EPA) is approving a state implementation plan (SIP) revision submitted by the State of Maryland. This revision pertains to removing a discontinued Technical Memorandum 90-01 (TM 90-01) from Maryland's SIP, which is now superseded by a new continuous emission monitoring (CEM) regulation. EPA is approving this revision to remove TM 90-01 from Maryland's SIP in accordance with the requirements of the Clean Air Act (CAA).