Control of HFC-23 Emissions

Hydrofluorocarbon (HFC)-23 is a potent greenhouse gas with a 100-year global warming potential (GWP) of 14,800. While there are limited instances where HFC-23 is captured, purified, and used for commercial purposes, the majority of HFC-23 is unintentionally created as a byproduct during the production of certain fluorinated compounds, including hydrochlorofluorocarbon (HCFC)-22. While HCFC-22 is an ozone-depleting substance that has been phased out domestically under the Clean Air Act in line with the international phaseout occurring under the Montreal Protocol on Substances that Deplete the Ozone Layer, it can still be produced for use as a feedstock to make other chemicals, such as low-GWP hydrofluoroolefins (HFOs). These HFOs can be used in many of the same applications as high-GWP HFCs, so transitioning to them can reduce emissions of greenhouse gases.

Unless sold for a consumptive use, controlled, or captured and destroyed, such creation of HFC-23 is ultimately vented to the atmosphere where it contributes to climate change. HFC-23 is not an air toxic and does not pose a direct risk to local communities, but climate change does threaten the public health of the U.S. population and especially those that may be vulnerable based on their characteristics or circumstances (see sections III and IV of 86 FR 55116, October 5, 2021).

EPA established requirements for all entities producing HFC-23 to control these emissions (40 CFR 84.27). Specifically, EPA requires under 40 CFR 84.27 that no later than October 1, 2022, no more than 0.1 percent of HFC-23 created on a facility line may be emitted (including any HFC-23 emissions during transportation to and destruction at a different facility), as compared to the amount of chemical intentionally produced on the line. EPA estimates that from 2022 through 2050 these HFC-23 emission control requirements will have abated cumulative emissions of more than 7,000 metric tons of HFC-23 or more than 3.7 million metric tons of carbon dioxide equivalent annually, and result in net present cumulative benefits of $6.4 billion in 2020 dollars at a three percent discount rate (see Regulatory Impact Analysis for Phasing Down Production and Consumption of Hydrofluorocarbons (HFCs) (pdf) (7.4 MB)). EPA also established a provision that allows chemical producers to request up to two six-month extensions of the compliance date.

One entity, Chemours Company FC, LLC, timely requested a six-month extension for its production facility in Louisville, Kentucky, due in part to supply chain difficulties that delayed acquisition of the necessary equipment to control HFC-23 emissions. EPA acknowledges that the primary purpose of the extension is to allow time to measure, validate, and optimize the effectiveness of the process change at the Chemours Louisville Works facility and that Chemours expects to complete this validation by the end of the year. The Agency granted this extension with the understanding that Chemours will have all necessary equipment onsite, operational, and effective by October 1, 2022, and will be running that equipment from that date onwards. With this understanding and our review of the submitted information, EPA granted the request to extend the compliance date for HFC-23 emission control requirements at Chemours Louisville Works to April 1, 2023 (see the Federal Register Notice).

EPA has monitored the facility’s progress on meeting the emission control requirements and has posted HFC-23 emissions data on the HFC Data Hub.