The International Institute of All-Natural Refrigeration (IIAR) has submitted a letter to the U.S. Environmental Protection Agency (EPA) asking that the agency retain the 100-year GWP limit of 150 for refrigerants in new cold-storage applications established by the Technology Transitions rule in the U.S. AIM Act and noting that the availability of natural refrigerant systems make that GWP limit a reasonable restriction for end users.
The letter, addressed to EPA Administrator Lee Zeldin and signed by IIAR President Gary Schrift, was sent in response to a March petition to Zeldin filed by the Coalition for the Use of Safe and Efficient Refrigerants (CUSER). The petition asked the EPA to raise the 100-year GWP limit for refrigerants in new cold-storage applications from 150 to 700 in order to allow the use of R513A. R513A, a blend of HFO-1234yf (56%) and HFC-134a (44%), has a 100-year GWP of 673 and a 20-year GWP of 1,823, per IPCC AR6 (2021).
The CUSER petition was signed by Eric Brown, chairman of CUSER and President of Alta Refrigeration, which markets R513A-based refrigeration systems. It was co-signed by 23 other manufacturing and contracting companies.
In addition, on May 14, Henry Bonar, President of Bonar Engineering, sent a letter to the EPA opposing the CUSER petition and including numerous examples of accidents involving f-gases.
The petition, and the letters from the IIAR and Bonar can be accessed here. Stakeholders who wish to send the EPA their own letters commenting on the petition can do so here, citing Docket ID number EPA-HQ-OAR-2025-0312; the deadline for comments is July 16.
Commenting on the CUSER petition, Danielle Wright, Executive Director of the North American Sustainable Refrigeration Council (NASRC), told NaturalRefrigerants.com that it “makes no sense. It doesn’t align with the real world data on ammonia installations and the growth trajectory of CO2 in the United States.”
Moreover, said Wright, “to be competitive on a global level, the U.S. needs to be using the most advanced cutting-edge technologies in refrigeration, which today are all exclusively below the 150-GWP limit. My biggest concern is that refrigerants like R513a may not even be available within the next decade. What will happen to all those stranded assets?”
‘Reconsideration’ of Technology Transitions Rule
The Technology Transitions rule, finalized in 2023, set a 150-GWP limit for new refrigeration systems used by supermarkets and cold-storage facilities, among other applications; the limit for cold storage begins January 1, 2026. But the EPA, following the Trump administration’s regulatory rollback agenda, announced on March 12 that it would engage in “reconsideration” of the Technology Transitions rule, though the agency has not yet formally started new rulemaking for the rule. The CUSER’s petition preceded that announcement on March 6.
The U.S. AIM Act, which includes three parts – the Technology Transitions rule, a phase down of HFC production and imports, and refrigerant management requirements – was enacted in late 2020 under the first Trump administration with bipartisan and industry support. In a recent interview with NaturalRefrigerants.com, Schrift spoke about the natural refrigeration industry’s concerns regarding the proposed rollback of the U.S. AIM Act.
The CUSAR petition argued that refrigerants that would satisfy a GWP limit of 150 are unavailable, unsafe or inefficient. But the IIAR letter noted that natural refrigerants such as ammonia (R717) and CO2 (R744) “have long been proven safe, efficient and sustainable and are the cornerstone of modern industrial refrigeration systems.”
The CUSER petition also contended that the other systems for which a 150-GWP maximum was set by the Technology Transitions rule were “smaller appliances [that] have only a fraction of the refrigerant charge and are completely different than cold storage in terms of design and manufacture.” However, CUSER did not include in its comparison transcritical CO2 systems used by large-format retail chains like Costco and Walmart, which also need to meet the 150 GWP limit.
In promoting the need for R513A, CUSER’s petition, said the IIAR letter, “serves the narrow interests of a few stakeholders, disregards the facts and ignores current technological realities.”
IIAR contends that the timeline established by the AIM act “is achievable because of the well-established history of using natural refrigerants, particularly for cold storage facilities.” Current natural refrigeration systems are already “in active, majority, and expanding use” and thus the cold storage sector “does not require a relaxation of the 150 GWP limit.”
The IIAR cited data from the 2023 Global Cold Chain Alliance (GCCA) Productivity and Benchmarking Survey report showing that 91% of responding cold storage facilities use ammonia, 10% use synthetic refrigerant and 5% use CO2 (R744). (Some employ multiple refrigerants, making the total exceed 100%.)
Industry standard
“Ammonia and CO2 systems are not ‘alternative’ technologies – they are the current industry standard,” said the IIAR letter. “The infrastructure of manufacturers, design firms, contractors, and educational institutions supporting natural refrigerants is mature and robust. These systems are cost-effective, energy-efficient, and readily available for immediate implementation.”
While ammonia systems have been available for cold-storage applications for many decades, CO2 refrigeration has more recently become a mainstream solution thanks to developments that allow for safe, efficient operation at high pressure, the IIAR letter said.
Developments such as reduced ammonia charge systems, advanced controls and adiabatic condensers have enhanced safety, reduced water consumption and increased energy efficiency for natural refrigerant systems, the IIAR letter said, adding that they can deliver up to 15% energy savings over synthetic refrigeration systems.
IIAR, the letter added, has helped safeguard ammonia systems by publishing ANSI-accredited safety standards that are recognized and referenced by national code bodies and considered good engineering practices by the EPA and other regulatory agencies.
IIAR also pointed out the potential health and environmental risks posed by certain f-gases, including R513A, which contains PFAS refrigerants that form another PFAS, trifluoroacetic acid (TFA) when leaked into the atmosphere.
