On September 29, 2021, the U.S. EPA issued a proposed rulemaking to require the control, capture, and/or destruction of a hydrofluorocarbon that would otherwise be emitted from manufacture of hydrochlorofluorocarbons. Specifically, EPA proposed to require companies to control, capture, and/or destroy HFC-23 byproduct generated at plants that manufacture class II ozone-depleting substances regulated under current Clean Air Act regulations, such as HCFC-22. Upon our consideration of comments and based on further action by EPA, EPA is now withdrawing the proposed requirements described in that proposed rule. This document summarizes the proposed rule and provides an explanation for the Agency's decision not to finalize the proposed action.