This action proposes to revise EPA's definition of Volatile Organic Compounds (VOC) with respect to requirements for preparing State Implementation Plans (SIPs) to attain the National Ambient Air Quality Standards (NAAQS) for ozone. The action would add (Z)-1-Chloro2,3,3,3,-Tetrafluoropropene (also known as HCFO-1224yd (Z); CAS # 111512-60-8) to the list of compounds excluded from the definition of VOC on the basis that this compound makes a negligible contribution to tropospheric ozone formation. This compound is not regulated as a hazardous air pollutant and is unlikely to contribute to stratospheric ozone depletion. It has low global warming potential compared to other compounds for which it can be used as a substitute. The VOC exemption petition was submitted by AGC Chemicals Americas, Inc., on July 29, 2020.