On August 31, 2020, in accordance with requirements under the Clean Air Act (CAA), the U.S. Environmental Protection Agency (EPA) performed a 5-year review of the Standards of Performance for New Stationary Sources and Emissions Guidelines for Existing Sources: Other Solid Waste Incineration (OSWI) Units, which includes certain very small municipal waste combustion (VSMWC) and institutional waste incineration (IWI) units. In the same action, the EPA proposed to remove the title V permitting requirements for air curtain incinerators (ACI) that burn only wood waste, clean lumber, yard waste, or a mixture of these three types of waste. In response to supportive comments received on the August 2020 proposal, this action is finalizing, as proposed, to remove the title V permitting requirements for ACIs that only burn wood waste, clean lumber, yard waste, or a mixture of those, and are not located at title V major sources or subject to title V for other reasons. The EPA is finalizing this proposed action now to simplify the compliance obligations for owners and operators of these types of units.