Ozone-depleting substances (ODS) are chemicals that have a deleterious effect on the stratospheric ozone layer. Since the United States became a signatory to the Montreal Protocol in 1987, EPA has regulated the production, import, consumption, use, destruction, and recycling of these chemicals. The ultimate goal is the complete phase-out of production of ODS in accordance with the Protocol’s time lines. Under the Clean Air Act, ODS are divided into two designations: Class I and Class II, listed at 40 CFR 82, Appendices A and B. Production of Class I ODS was phased out in January 2000, while Class II ODS are on schedule to be phased out by January 2030.