Trifluoroacetic acid (TFA), a persistent pollutant known as a forever chemical, has more than tripled in the global environment over the past two decades, largely due to refrigerants that protect the ozone layer. While current levels remain below known safe thresholds, the chemical's long-term accumulation raises concerns for human health and aquatic life. Researchers urge scrutiny of newer replacements to avoid unintended environmental consequences.
The rise in TFA stems from the atmospheric breakdown of hydrofluorocarbons (HFCs), which replaced chlorofluorocarbons (CFCs) after their 1989 ban for depleting the ozone layer. CFCs, once common in refrigerators and aerosols, were phased out globally under the Montreal Protocol. HFCs, though ozone-safe, contribute to global warming and degrade into TFA when reacting with hydroxyl radicals in the air.
According to a study led by Lucy Hart at Lancaster University, UK, TFA deposition has increased from 6,800 tonnes annually in 2000 to 21,800 tonnes in 2022—a 3.5-fold rise. Ice core samples from northern Canada and Svalbard confirm concentrations have been climbing since the 1970s. Projections suggest this could double by 2050 from HFCs alone, with newer hydrofluoroolefins (HFOs) potentially multiplying production by over 20 times. For instance, HFO-1234yf, used in millions of car air conditioners, generates 10 times more TFA than the HFC it replaces.
TFA's persistence means it lingers in soil and surface water for decades or centuries before reaching ocean sediments. Animal studies show it caused eye deformities in most exposed rabbit fetuses, and the European Union classifies it as harmful to aquatic life while considering it toxic to human reproduction. A 2020 study found high TFA levels in the blood of 90 percent of people tested in China, a production hotspot due to industrial activity and climate.
"It is shocking that we’re emitting large amounts of a chemical into the environment that we have a very poor understanding of its impacts, and it’s irreversible basically," Hart said. Lucy Carpenter at the University of York, UK, echoed calls for alternatives like ammonia or carbon dioxide, natural refrigerants already used in some industrial settings. "We need to take a serious look at whether there are better alternatives to HFO-1234yf," she added, noting TFA's growing presence in food products.
The EU is developing forever chemical bans and predicts rising freshwater concentrations could turn toxic, though a hired consultancy—linked to chemical industry lobbying—disputes this. Hart emphasizes that HFOs degrade quickly, allowing rapid control: "If we stop emitting them, you’ll stop TFA production very quickly." The research, published in Geophysical Research Letters, highlights the need to evaluate replacements to prevent repeating past mistakes with ozone-depleting substances.
