Trifluoroacetic acid (TFA), a harmful “forever chemical,” has increased more than threefold in our environment in the past two decades due to the use of refrigerants that harm the ozone layer.

The annual deposition of TFA from the atmosphere rose from 6,800 tons in 2000 to 21,800 tons in 2022. While this level is below certain safety limits, detailed studies on TFA’s impact on human health are limited, and its environmental accumulation is expected to grow.

TFA was linked to serious deformities in rabbit fetuses during one study. The European Union has flagged TFA as hazardous to aquatic ecosystems and is evaluating its impact on human reproductive health.

“It is alarming that we are introducing so many chemicals into our environment with largely unknown repercussions, and many of these effects are irreversible,” states Lucy Hart, a researcher from Lancaster University in the UK.

Both humans and wildlife encounter TFA through contaminated soil and surface water, from which it eventually contaminates ocean ecosystems and marine sediments over decades or centuries.

Chlorofluorocarbons (CFCs), once prevalent in refrigerators, aerosol propellants, and fire extinguishers, were banned in 1989 after they were found to deplete the ozone layer. Most CFCs have now been replaced with hydrofluorocarbons (HFCs), which react with atmospheric particles to produce TFA.

HFCs are currently being phased out, often substituted with hydrofluoroolefins (HFOs) that degrade to TFA at a significantly faster rate. For example, HFO-1234yf produces ten times more TFA than the phased-out HFCs used previously in hundreds of millions of vehicles. Additionally, pesticides, pharmaceuticals, and industrial processes contribute to TFA levels.

Ice core samples from northern Canada and Svalbard indicate rising TFA concentrations since the 1970s. Hart and her team evaluated TFA production and global deposition based on extensive atmospheric studies of nine CFC replacements, observing a 3.5-fold rise worldwide.

Focusing solely on HFCs, known to linger in the atmosphere for many years, indicates that this rate could potentially double by 2050. Preliminary findings suggest that HFO-1234yf could enhance TFA production by more than 20 times by 2050.

The global community must avoid reverting to CFCs and should continue to eliminate HFCs, which significantly contribute to climate change. However, alternatives to these compounds require thorough evaluation, emphasizes Lucy Carpenter from York University, UK.

Ammonia is already utilized in various food storage facilities and industrial applications and could be adapted for domestic refrigeration and air conditioning. Carbon dioxide also serves as a viable natural refrigerant.

“It is critical to explore better alternatives to HFO-1234yf,” Carpenter notes. “TFA is on the rise and it’s now pervasive in various consumer products and environments.”

A 2020 study found alarming levels of TFA present in the blood samples of 90% of individuals in China, which has emerged as a hotspot for TFA due to industrial emissions and its warm, humid climate.

The EU is proposing a permanent ban on TFA, foreseeing that concentrations in freshwater may reach toxic levels. However, it faced criticism for leaning towards chemical companies to contest this anticipated rise in TFA levels.

Recent findings serve as a clarion call for increased research into HFOs and their substitutes to prevent the cycle of introducing chemicals with unintended consequences, emphasizes Hart. Unlike HFCs, HFOs decompose rapidly, providing more immediate control over emissions. “Halting these emissions will lead to an immediate stop in TFA production,” she states.