The Natural Refrigeration

When the U.S. Environmental Protection Agency finalized its Reconsideration of the Technology Transitions Rule in May 2026, it introduced extended compliance dates, relaxed interim GWP limits, and installation flexibility for several subsectors including cold storage. While many in commercial refrigeration saw the reconsideration as a reprieve, it may have introduced unanticipated regulatory challenges from several states.

Now, three months after the rule went into effect, a patchwork of more stringent state regulations –some even more restrictive than the original rule – are taking effect. New York, California and Washington have all passed their own equivalents of the TT Rule, and other states may follow suit.

Meanwhile, growing concern over trifluoroacetic acid, the polluting PFAS component of synthetic refrigerants, could mean that states nationwide, led by eight states that already have PFAS restrictions, may enact anti-PFAS legislation adding to state-level pressure on HFO’s.

Adam Shorey, Vice President of Therm Solutions and Chairman of IIAR’s Responsible Refrigerants Committee, said the TT extension offered some relief from uncertainty for end users now that it has been re-ruled. “But it really is just kicking the can down the road, which is a setback,” he said, adding that the net effect for IIAR is that “we’ll have to wait a little longer for this transition [to natural refrigerants] to happen.”

“Unfortunately, there are just a lot of end users who wanted to continue to use [cheaper] synthetics. Our hope was that the original rule would push people towards IIAR and naturals, and that may not happen as readily,” he said.

Nevertheless, synthetic refrigerant users planning to comply with the extended 2023 deadline will still need to consider that new phasedown limits will push them towards refrigerants with A2L fire ratings, which come with more stringent regulatory requirements than traditional HFC’s.

“With the application of the TT Rule that provides for 150 GWP thresholds, people who still want to use freon would have to apply the system a little differently,” said Reed Portney, Sales Manager for Packaged Systems at Evapco. “In the past, they could get away with bypassing [safety measures] we consider standard in ammonia refrigeration. They now have to apply some of those things based on the flammability ratings of their new refrigerants.”

Part of the AIM Act is to promote natural refrigerants, said Portney. “Once that 150 GWP limit is enacted, it becomes more difficult to see regulatory limitations as a deterrent for ammonia. In the past, customers might have said ammonia systems are overly burdensome from a regulatory standpoint compared to synthetics, but now they will be in line with each other a little bit more.”

While the new A2L flammability requirements may eliminate discrepancies in regulatory burdens around the use of HFO’s and natural refrigerants, the bigger issue for commercial end users may be the development of a patchwork of regulations at the state level created by the delay of the TT Rule.

“For manufacturers, shifting timelines can certainly create some challenges. Product development, capacity planning, inventory management, and customer investment decisions are all tied to regulatory expectations. When implementation dates change, it can create uncertainty in the market and we much prefer certainty from the federal level than a patchwork of state and local regulation,” said Lauren MacGowens, Director of Transformation & Sustainability for Vilter.

Nevertheless, now that the TT Rule has been extended from 2026 to 2032, the delay may not turn out to be as much of a positive as that industry was hoping. That’s because states are beginning to roll back the extension on their own, creating a patchwork of local regulations that may complicate compliance for end users with facilities across different regions.

“The back and forth over the rule extension should be over now, but the uncertainty and the revocation of the rule has now left the door open for states to do things like introduce their own versions,” said Shorey.

“I think states are looking at this as a situation where they were moving towards this rule and now it’s not a rule anymore, but this preparation for the original rule has already happened – and many of them are going to go ahead and enact either the original requirements or something close to them.”

After EPA finalized its 2026 reconsideration of the Technology Transitions Rule, New York moved quickly to adopt its own version of the rule, restoring the original, more aggressive timelines. The state’s Department of Environmental Conservation made clear that the federal rollback conflicted with New York’s climate mandates under the Climate Leadership and Community Protection Act, which requires steep reductions in greenhouse gas emissions across all sectors.

New York’s rule effectively reinstates the original Technology Transitions deadlines and GWP caps, rejecting EPA’s extensions for supermarket systems, cold storage warehouses, industrial process refrigeration, and other categories.

Where EPA now allows interim GWP limits of 700 or 1,400 through 2032, New York maintains the 150/300 GWP thresholds and the earlier installation cutoffs, keeping the state aligned with California, Washington, and other jurisdictions that have chosen not to follow the federal delay.

“New York has moved aggressively here,” said Shorey. “They’ve gone above and beyond even the TT Rule. My guess is that more and more states will do their own thing like New York, and this causes complexity because now you have to comply with one set of regulations for one state and another for another.”

Evapco’s Portney agreed with Shorey that the extension of the TT Rule may initially result in a slower transition to naturals, and even an uptick in freon in the near term, but that the net effect of the AIM Act, and factors beyond it, like the emerging state regulation of PFAS polluting HFO’s will eventually push end users towards natural refrigerants.

“I expect there to be an uptick in freon for a few years in different sectors across the AIM Act, because some end users will be trying to push through certain refrigerants for certain applications before these limits take effect in 2032,” said Portney. “But a large number of customers already use ammonia, so for the industrial process market, that will continue to be dominated by the ammonia refrigeration industry.”

For those still deciding between a long-term commitment to HFOs or naturals, there are already plenty of end users trending toward ammonia, and that may have more to do with emerging PFAS regulations at the state level than the AIM Act, said Portney.

Several U.S. states have begun moving directly into PFAS restrictions, even though no state has yet enacted a refrigerant specific PFAS ban. Instead, states are regulating PFAS as a class across broad product categories. The result is a regulatory environment where PFAS containing substances like HFO’s may face future bans.

The states with the broadest PFAS phaseouts are Maine, Minnesota, Colorado, Vermont, California, Connecticut, Washington, and New York, all of which have active PFAS restrictions or reporting requirements. Several states, including Maine, Minnesota, and Colorado, have enacted frameworks that phase out PFAS across all product categories by 2032 unless a use is deemed unavoidable.

“States are starting to implement their own restrictions around PFAS, and because of that, end users are starting to look at all of these state-specific and region-specific limitations, not just the ones that address the TT Rule,” said Portney.

“We recommend looking at what the AIM Act has to say, then look at what the state and local jurisdictions have to say, then look at the holistic picture to decide what’s best, and once you figure that out, you figure out what you can and can’t do for the future.”

“Plenty of people are going to come to the conclusion that they should choose ammonia or CO2,” said Portney. “Even outside of the states where more stringent AIM Act policies exist, a certain subset of facility owners are going to come to the conclusion that natural refrigerants are the best choices for the future.”

Portney cited the emerging state-level PFAS regulations as the next biggest cause of regulatory uncertainty for end users. “There are already many states examining the PFAS issue, and plenty of designers and engineers have seen enough of this over the years with HFC’s and HFO’s. I think they are increasingly concluding that natural refrigerants might be best for their applications,” he said.

“Now [with the state-level TT Rules] we have a precedent for what might happen with PFAS. HFC’s are being phased out, even with a delay, and there are these issues surrounding HFO’s, so there are a number of people now who would rather move on from synthetics and look at other options like natural refrigerants.”