The Natural Refrigeration

In the mid-2000’s, when PFAS “forever chemicals” were first classified by the United Nations Environmental Programme, they were just beginning to be understood as dangerous pollutants. As the evidence mounted for their role in cancer and other health problems, regulators and activists began to outlaw PFAS sources, chief among them, many pesticides commonly used in agriculture.

Now, nearly two decades later, a new industrial PFAS contaminant is looming . . . hydrofluoroolefin, or HFO, refrigerants. HFO refrigerants – used anywhere industrial refrigeration is needed, from cold storage to data centers – release into the atmosphere, where they break apart to form trifluoroacetic acid, or TFA. TFA is a short-chain PFAS that falls back to Earth near the site of the release, continually accumulating in the water and soil of the nearby communities.

Without rapid intervention, TFA concentrations in water are projected to rise by 10-to 100-fold by 2040, exceeding existing safety thresholds. PFAS contamination is fast approaching what scientists call a “planetary boundary threat,” beyond which the ability of natural systems to support human survival is uncertain.

That threat is addressed in the new IIAR white paper: Environmental and Health Risks of Synthetic PFAS Refrigerants. “There’s a threshold where we can’t go back [from HFO contamination], so this message has to get to the mainstream now,” said Tim Cook, IIAR member and one of the four authors of the paper. “This is a little different than climate change, where some people can’t see the visible signs of environmental degradation because they live in places that aren’t visibly affected. These [refrigeration] plants are everywhere in the world.

This impacts people wherever they are. Industrial refrigeration is present in every community in the US. And every community in the US will face this risk.”

Cook, along with authors Stephanie Smith and John Flynn, used the paper to lay out the environmental risks posed by HFOs.

“This paper is important because of the message it sends, and that message is that right now is the time to do the work of educating the public on this risk,” said Smith, adding that IIAR has taken on that work because it aligns closely with the organization’s mission.

“The general public does not know about this particular area, which is a potentially huge exposure. It’s very important to start those discussions now, before the worst contamination can happen,” said Smith.

“We don’t have widespread HFO-generated contamination yet, but if HFO’s are widely adopted due to the impending phaseouts [of HFC’s], we will. This is a silent threat creeping up on us.”

The three authors said one of the most important goals IIAR hopes to accomplish with the whitepaper is to communicate that the world is at a crucial threshold regarding the threat posed by synthetic refrigerants.

Like the first generation of PFAS contaminants, HFO refrigerants are widely used. But unlike in agriculture, the industrial refrigeration industry already has PFAS free alternatives that have been in use for a century.

IIAR said one purpose of the paper is to give members a reference point as they advise customers, end users, and even regulators on the benefits of choosing natural refrigerants instead of HFOs. This education will be especially important as HFC phaseouts push refrigeration users to decide to adopt HFOs or switch to natural refrigerants. And the rate at which HFOs are adopted to replace HFCs will determine whether the worst contamination can be avoided.

The timing of this refrigerant choice will be pivotal, said Smith. The 15-year EPA-mandated phasedown of HFCs began in 2022, and synthetic refrigerant manufacturers are already positioning the new generation of HFO refrigerants as drop in replacements for the phased-out HFCs.

Nevertheless, the change in flammability classification that new synthetic refrigerants carry may present an opportunity to sway end users to choose natural refrigerants instead.

Historically, the difference between ammonia, which is classified as a mildly flammable B2L refrigerant, and the older generation HFCs, which were classified as A1 refrigerants, presented a price differential. More flammable refrigerants were simply more expensive to use, making synthetic refrigerants the least expensive choice.

However, the new generation of HFOs are now classified as mildly flammable A2L refrigerants, similar to ammonia’s B2L classification.

“It really levels the playing field now that these new refrigerants have A2L classifications,” said Flynn. “Ammonia detection or mitigation could add thousands of dollars to the cost of a system, so many owners chose A1 refrigerants to save on that expense. But now HFOs will face similar requirements for detection and mitigation.”

Another factor working in favor of natural refrigerants may be the regulatory uncertainty that synthetic refrigerants carry. Much like HFCs when they were new, said Flynn, there’s currently not much knowledge about the environmental risks posed by HFOs.

“As I work with our clients, many of them are facing changes in regulatory requirements, and many are facing decisions about which refrigerant they’re going with. There’s a lot of confusion on which refrigerants will be accepted long-term and which won’t.”

“When HCFCs were found to be ozone depleting, the chemical industry came out with HFCs, only to find that there was a different environmental impact, called global warming. And now we’re at that same point again with HFOs and PFAS contamination.”

Realistically, synthetic refrigerants will never be entirely off the market. “But if companies, designers, and others in our industry can make the decision to use natural refrigerants instead, we go a long way towards doing our part to prevent this contamination,” said Smith. “That’s the point IIAR is trying to make, that there are already these good options on the table with natural refrigerants.”

“Right now, PFAS toxicity levels are relatively low, but they’re growing fast. So, we have this brief window of time where we can really do something. There isn’t a lot of room for mistakes or saying, ‘we’ll get to it later,” said Smith.

Fortunately, Europe has already become the model the US could follow for implementing PFAS source limits. With widespread contamination, ongoing sources of TFA contamination, and concerns about toxicity, there is a strong call for action within the EU and its regulatory bodies. Recent studies show TFA in 94% of EU drinking water samples, with concentrations generally higher than those of other PFAS.

The outlook for EU regulation indicates that the EU is moving toward a universal restriction on PFAS, with a decision expected after 2025. If successful, this would likely include phased bans and some exceptions for essential uses. While TFA is not specifically regulated, it is under increasing scrutiny due to its environmental persistence, widespread presence, and emerging evidence of toxicity.

The US can start to address the problem by following Europe’s lead, said Cook. But as with anything, the effort begins with awareness. “Europe is way further down the line in outlawing PFAS sources and looking at the health risks posed by PFAS because their limits are much stricter. This is an area where we need to catch up with the rest of the world – and quickly,” said Cook. “And with natural refrigerants as alternatives – why wouldn’t you?”

One answer, said Smith, is that people don’t really know that HFO-contributed PFAS is such a big risk, or what they can do about it. “This is one of the reasons IIAR published this paper. IIAR should be educating refrigeration users as they decide if synthetic refrigerants are really the good long-term solution for their needs. Dollars and cents decisions are one thing, but if you have a plant where you, or your employees, live nearby, and you’re introducing this kind of environmental risk, the decision becomes bigger than the balance sheet,” said Cook.