Are “Earth-Friendly” New Refrigerants Toxic?

Bills have been introduced in both the House and Senate to restrict hydrofluorocarbons (HFCs), the refrigerants currently used in most air conditioning and refrigeration systems. But now, one of the leading substitutes for HFCs has been identified as a potential toxin.

The history of refrigerant regulation is a long and complicated one. Decades ago, a widely used class of compounds called chlorofluorocarbons (CFCs) were blamed for the depletion of the earth’s ozone layer—the infamous ozone hole. As a result, CFCs, along with a related class of refrigerants called HCFCs, were phased out under the United Nations’ 1987 Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol). The U.S. ratified the Montreal Protocol and also included CFC and HCFC restrictions in the 1990 Clean Air Act Amendments.

In the decades since, HFCs became the leading substitute refrigerants used in most home air conditioners and refrigerators, nearly all vehicle air conditioners, and the equipment in millions of businesses like supermarkets and restaurants as well as air-conditioned commercial properties.

But now, many environmental organizations have soured on HFCs, blaming them for contributing to climate change. And they have found common cause with opportunistic manufacturers of costly substitute refrigerants and equipment designed to run on them. One such substitute, called HFO-1234yf—under patent by two companies, Honeywell and Chemours—would replace HFC-134a which currently dominates in car air conditioners and is used in other cooling equipment. Indeed, automakers have already begun the transition to HFO-1234yf in new vehicles.

Restrictions on HFCs have already been added to the Montreal Protocol in 2016, but the U.S. has not yet ratified these provisions. So now, a powerful coalition of green groups and rent-seeking manufacturers is pushing for domestic legislation targeting HFCs and thereby create a de facto mandate for HFOs and other putatively greenhouse-friendly substitutes.

However, scientists are raising concerns that HFO-1234yf may be a toxin. A paper published in Geophysical Research Letters finds that HFCs break down in the environment into potentially dangerous trifluoroacetic acid (TFA), but that HFOs are even worse in this regard. It concludes that “replacement of HFC‐134a with the short‐lived hydrofluoroolefin (HFO) HFO‐1234yf as the coolant in mobile air conditioners will lead to an increase in TFA deposition.”

Granted, the concerns over TFA deposition may well prove overstated. Nonetheless, it is one of many reasons to resist legislation restricting HFCs. The corporate rent-seeking behind these bills should be of great concern. HFO-1234yf costs nearly 10 times more than HFC-134a; the resultant costs to consumers would be significant. And the climate threat posed by HFCs and thus the benefits of restricting them are likely overstated. Altogether, the case against HFC restrictions is overwhelming.