HFO Commercial Uses in the United States: Strictly Regulated, Rigorously Studied
EPA, International Organizations Find TFA Currently Pose No Risk to Health or the Environment
Advanced solutions for the refrigeration and air conditioning industry depend on fluorinated gases, such as hydrofluoroolefins (HFOs), to enable heating, ventilation, air conditioning, and refrigeration (HVACR). HFOs are short chain substances (≤ C5 chains) that do not meet the criteria of being classified as persistent, bioaccumulative and toxic substances (‘PBT’) and are a key pathway to help decarbonize the economy, mitigate the effects of ground-level smog formation, avert climate change and phase down potent greenhouse gases. HFOs are some of the most studied compounds in use today and undergo rigorous toxicity testing before being approved by U.S. government regulators for commercial use. The United Nations Environmental Program’s Environmental Effects Assessment Panel has determined that trifluoroacetic acid (TFA), a breakdown product of some HFOs, poses no significant risk to humans or the environment.
HVACR HFO Applications
Utilizing HFOs enable safer, sustainable, and efficient refrigeration systems that meet critical societal needs, such as:
Preserving agricultural produce, dairy, meat, and seafood.
Protecting the pharmaceutical cold chain, including vaccines.
Decarbonizing large-scale heating solutions, such as heat pumps.
Supporting global solutions for residential, commercial, and mobile air conditioning.
Classifying HFOs and TFA
The EPA’s PFAS reporting program under the Toxic Substances Control Act (TSCA) does not classify HFOs as PFAS. The Agency’s reporting rule, released in 2023, requires manufacturers to report uses, production volumes, disposal, exposures, and hazards of approximately 1,500 PFAS. In addition, the EPA’s National PFAS Testing Strategy states that TFA are “a well-studied non-PFAS.”
EPA SNAP Regulated HFO Uses
HFOs have an ultra-low global warming potential similar to the non-fluorinated older industrial refrigerants. HFOs serve as viable replacements for HFC substances that are regulated by the EPA under the AIM Act, and are critical to the U.S.’s ability to meet its international environmental obligations under the Kigali Amendment to the Montreal Protocol, an international agreement to phase down the consumption and production of HFCs that was ratified by Congress in 2022.
The EPA’s Significant New Alternatives Policy Program (SNAP), established under the Clean Air Act and charged with approving substances under the Kigali Amendment, has approved HFOs as sustainable alternatives for various commercial uses for over a decade after continuously studying their hazard and risk profiles. As part of these evaluations, EPA examines the atmospheric effects and related health and environmental impacts, general population risks from ambient exposure to compounds with direct toxicity and to increased ground-level ozone, ecosystem risks, occupational risks, and consumer risks, among others.
SNAP-Approved HFOs Affirm Safety, Sustainability Profiles
SNAP’s most recent final rule, SNAP Rule 26, approves HFOs as acceptable with use conditions for the refrigeration and air conditioning sector – specifically for new industrial process refrigeration, cold storage warehouses, retail food refrigeration, commercial ice machines, and ice skating rinks. Additional applications approved under previous SNAP rules include motor vehicle air conditioning, mobile refrigerated transport, residential and light commercial air conditioning and heat pumps, construction and refrigeration (appliance and commercial) insulation, and more.
Scientific Findings: TFA Currently Do Not Pose Risk to Human Health or the Environment At Expected Concentrations
EPA: In 2024, EPA’s SNAP Rule 26 concluded, “Any increase in TFA deposition due to this rule is expected to be less than the modeled increases in TFA from studies that found the levels of TFA in the environment remained, ‘too small to be a risk to the environment over the next few decades.’”
DOE: In 2023, the U.S. Department of Energy’s Oak Ridge National Lab emphasized, “The WMO (2022) and the UNEP EEAP (2022) reports show an increased confidence that TFA produced from the breakdown of new low-GWP refrigerants will not harm the environment over the next few decades.”
EEAP: In 2022, the Environmental Effects Assessment Panel (EEAP) of the Montreal Protocol found, “The increases in trifluoroacetic acid (TFA) concentrations due to replacements of the ozone-depleting substances are not expected to pose significant risk to humans or the environment at the present time.” EEAP adds, “Trifluoroacetic acid (TFA) continues to be found in the environment, including in remote regions, although concentrations are so low that they are currently very unlikely to have adverse toxicological consequences for humans and ecosystems.” EEAP states that “TFA does not bioaccumulate nor is it toxic at the low to moderate exposures currently measured in the environment or those predicted in the distant future”, noting that “[b]ecause of its lack of reactivity, TFA salts are persistent in the environment and estimates of half-life are uncertain but could be in the range of centuries or millennia. This persistence is not a major concern because it does not react with biomolecules. TFA and its salts are easily excreted by animals and do not bioaccumulate in food chains.”
WMO: In 2022, the World Meteorological Organization stated, “The concentration of TFA in rainwater and ocean water is, in general, significantly below known toxicity limits at present.” WMO added, “Trifluoroacetic acid (TFA)… is not expected to harm the environment over the next few decades.”
UNEP: In 2016, the United Nations Environment Programme (UNEP) concluded, “Based on current projections of uses, the amount of TFA formed from hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), and hydrofluoroolifines (HFOs) in the troposphere is too small to be a risk to the health of humans and the environment.” UNEP added: “Based on worst-case exposure scenarios for salts of TFA, risks to mammals, to plants growing in soil and to aquatic organisms is currently considered de minimis.
Safety Margin: According to a 2024 research paper by 40 scientists that examined published studies on TFA toxicity, while the TFA concentration in drinking water may reach the level of 210 ng/l, the No Observable Adverse Effect Level for TFA is 10 mg/kg, which is 50,000 times higher.
DOD: Losing Access to HFOs Poses Risk to National Security
In its 2023 “Report on Critical Per- and Polyfluoroalkyl Substance Uses,” the Department of Defense states that “[l]osing access to PFAS due to overly broad regulations or severe market contractions would greatly impact national security and DoD’s ability to fulfill its mission.”
The report explains, “Under the AIM Act and EPA technology transition regulations, the U.S. economy is in the process of switching from one set of PFAS-classified refrigerants (e.g., HFCs) to a new generation of refrigerants (e.g., HFOs)… Known non-PFAS alternatives (e.g., hydrocarbon or ammonia alternatives) pose flammability, toxicity, or high-pressure concerns. The same PFAS that are used in quantities of several hundred million pounds per year throughout the U.S. economy for cooling applications are used in much smaller quantities (i.e., a fraction of one percent) for military cooling and military thermal control of all kinds.”