HFC-23 Emission Standards For Production Of Class II ODS | US EPA

Skip to main content

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Breadcrumb

1. Home
2. Phaseout of Ozone-Depleting Substances
3. ODS Production, Destruction, Import, and Export

HFC-23 Emission Standards for Production of Class II ODS

Under Title VI of the Clean Air Act (CAA) and the implementing regulations, the production and consumption of class II ozone-depleting substances (ODS), (i.e., hydrochlorofluorocarbons (HCFCs)), are restricted with limited exceptions. One exception is production for use in transformation, or as a feedstock, which is allowed indefinitely.

Hydrofluorocarbon-23 (HFC-23) is a very potent greenhouse gas (GHG) with a 100-year global warming potential (GWP) of 14,800 that is generated as a byproduct during the manufacture of certain chemicals, including HCFC-22.

On September 29, 2021, EPA published a proposed rule that would have required companies to control, capture, and destroy HFC-23 byproduct generated at plants that manufacture HCFCs, such as HCFC-22. Under the proposed action, any plant that manufactures HCFCs would have been required to control, capture, and, if not used for a constructive purpose, destroy HFC-23 byproduct emissions. More specifically, EPA proposed that no later than October 1, 2022 (unless deferral is granted), as compared to the amount of HCFCs intentionally manufactured on a facility line, no more than 0.1 percent of HFC-23 generated on the line may be emitted.

On June 16, 2022, EPA published a notice at 87 FR 36282 withdrawing this proposed rulemaking because it is duplicative and unnecessary because similar standards were implemented under AIM Act authority. On October 5, 2021, EPA finalized a rule, “Phasedown of Hydrofluorocarbons: Establishing the Allowance Allocation and Trading Program under the American Innovation and Manufacturing Act” at 86 FR 55116, which codified regulatory standards for these HFC-23 byproducts (40 CFR 84.27). Under the HFC Allocation Rule, all generation of HFC-23 is regulated, including HFC-23 generated as a byproduct during production of HCFCs for feedstock use.

• Federal Register link to the withdrawal notice.
• Federal Register link to the proposed rule.

To view the withdrawal notice, proposed rule, and the public docket on http://www.regulations.gov, search for Docket ID number EPA-HQ-OAR-2021-0253.

Phaseout of Ozone-Depleting Substances

Open Sidenav Menu Close Sidenav Menu

• Overview of ODS Phaseoutexpand or collapse the child menu
  • Class I ODS
  • Class II ODS
  • HCFC Allowance System
• ODS Production, Destruction, Import, and Exportexpand or collapse the child menu
  • Importing
  • Labeling
  • Recordkeeping and Reporting
  • Destruction Technologies
  • Process Agents
  • Emissions Standards
• Exemptions to the ODS Phaseoutexpand or collapse the child menu
  • Methyl Bromide
  • Essential Uses (Metered-Dose Inhalers)
  • Laboratory and Analytical Uses
  • Halons Program
• For Equipment Owners, Operators, and Consumers

Contact Us about Phaseout of Ozone-Depleting Substances Contact Us about Phaseout of Ozone-Depleting Substances to ask a question, provide feedback, or report a problem. Last updated on April 21, 2025