Maine’s emerging chemical threat in our home appliances

An environmental threat is emerging in Maine and throughout the world from the refrigeration chemicals that replaced ozone-depleting chlorofluorocarbons after they were banned in 1987.

The toxic compound, trifluoroacetic acid, or TFA, is a byproduct of the chemicals now widely used in aerosol products and to cool refrigerators, air conditioners and heat pumps. It is produced when those chemicals, known as hydrofluorocarbons, degrade. TFA is widespread and has been increasingly found in drinking water and rain worldwide in recent decades, causing environmental experts to worry about possible undetected health risks.

So far, Maine and the federal government are not regulating or testing for TFA, which is considered by many to be a forever chemical. Scientists are concerned that the chemical, which is difficult to both test for and get rid of because its molecular structure is small, is increasing rapidly in the global environment since the ban of chlorofluorocarbons nearly four decades ago.

Scientists haven’t agreed on whether it poses a risk to human health, although European studies suggest it may affect fertility and liver health. The European Pesticide Action Network reported that TFA was detected in 34 of 36 European tap water samples tested from 11 European Union countries and in 12 of 19 bottled mineral and spring waters. It also reported that it found TFA in almost all of the 23 surface water and six groundwater samples it tested from 10 European Union countries.

“It’s a global problem, so it applies to Maine,” said Gail Carlson, assistant professor of environmental studies and director of the Buck Lab for Climate and Environment at Colby College in Waterville. “What you are learning about it elsewhere applies here. Which, of course, makes it a chemical of concern.”

The Maine Center for Disease Control and Prevention’s Drinking Water Program has not sampled public water supplies for TFA and does not currently have plans to do so, said spokesperson Lindsay Hammes. That also is the case with the Maine Department of Environmental Protection, which has been testing hundreds of private wells throughout the state for a suite of forever chemicals that does not include TFA.

Maine is somewhat hamstrung by the federal designation for TFA. The U.S. Environmental Protection Agency does not classify TFA as a per- and polyfluoroalkyl substance, or PFAS, forever chemical. However, Maine, 22 other states, the U.S. Department of Defense and Congress consider TFA to be a forever chemical. The federal definition makes it more difficult for states to set exposure limits and other restrictions.

PFAS are a large group of synthetic chemicals that are resistant to heat, grease, water and oil, and they do not break down readily in the environment. They are believed to affect the immune system and liver enzymes, and have been linked to kidney and testicular cancers, according to the U.S. Agency for Toxic Substances and Disease Registry.

The difference in the federal and Maine designations comes down to one atom. The EPA does not recognize TFA as a forever chemical because only one of its two carbon atoms is bonded to a fluorine atom. The agency considers forever chemicals to have at least two carbon atoms bonded to fluorine atoms. Other groups have called the agency’s definition inadequate because the carbon-fluorine bond is considered the strongest in organic chemistry and makes the compounds nearly impossible to break down. Many of the most well-studied PFAS chemicals, such as perfluorooctanesulfonic acid, or PFOS, have eight carbon atoms.

Another difference in the EPA’s approach is that it classifies different types of PFAS individually. However, scientists look at PFAS as a group of substances, an approach that casts a wider net on which potentially harmful chemicals could be regulated. In February, some 150 scientists around the world published a letter asking government agencies to broaden their definition of PFAS to include TFA.

The different definitions have stalled Maine regulators’ addition of TFA to accredited laboratory tests for PFAS, so it is not included in common water testing panels.

“The decision to add TFA to the accredited tests would be a federal decision by EPA or FDA [U.S. Food and Drug Administration], who would determine whether and when to modify laboratory methods to include TFA,” said David Madore, a spokesperson for the Maine Department of Environmental Protection.

That won’t stop private laboratories from testing for it when a customer requests it. Maine Laboratories in Norridgewock, the state’s first lab to test for forever chemicals in drinking water and soil, plans to start testing for TFA in three months or so after receiving some inquiries about the chemical, said Katie Richards, CEO of the lab. Testing for TFA involves recalibrating scientific instruments to handle the small compound and finding the chemical mixtures to test for it.

Richards said she is not surprised that the country and Maine are not testing for TFA given the wide response of states to PFAS in general, with some turning a blind eye to the forever chemicals.

“Maine in general has been very forward thinking,” she said. “Our company will develop custom tests for customers.”

The lab, which opened in February 2023, recently added three employees and plans to hire another in August. It can handle 2,500 PFAS tests per year now, but it has plans to quadruple that and double the number of employees to eight or 10 in about six months.

The U.S. National Institutes of Health defines TFA as a colorless, fuming liquid with a pungent odor, although it can exist as a gas under certain conditions. It is corrosive to skin, eyes and mucous membranes. It is used as a solvent and a refrigerant.

The compound gets into the air and water mainly from refrigerants that leak from air conditioning and heat pumps, and smells like vinegar. Those refrigerants can degrade into TFA. Other products with chemicals that can degrade into TFA include dyes, pesticides and pharmaceutical drugs. TFA is used to make the COVID-19 antiviral pill Paxlovid, according to the journal Biochemistry Research International.

“TFA is everywhere, so it is in everyone’s bodies, but few health studies have been done on it,” said Katie Pelch, senior vice president of environmental health at the Natural Resources Defense Council. “TFA molecules are small, so the options to capture it are limited.”

The hydrofluorocarbons used widely in today’s cooling appliances replaced ozone-depleting chlorofluorocarbons, or CFCs, as a safer alternative. CFCs, which became popular in the 1930s, had replaced so-called “natural refrigerants,” including carbon dioxide, propane, isobutane and ammonia, that were used when home refrigeration became popular in the 1920s.

The natural refrigerants were flammable, said Richie Kauer, senior super pollutant reduction advocate at the Natural Resources Defense Council. They are once again being used by some appliance makers, with enhanced safety features, she said.

“But in the refrigerant world, none of the alternatives is risk free,” she said. “I think it’s important for the average consumer to be aware that we are constantly being exposed to PFAS chemicals.”

That creates tough decisions for consumers between using air conditioning that may contain PFAS chemicals during a heat wave or becoming ill by not getting cool. With few alternatives available to PFAS-containing products, consumers can’t “shop their way around PFAS,” she said.

“It’s a tough problem to solve because heating and cooling are absolutely essential,” Kauer said.

Few customers are asking about PFAS in relation to heat pumps, which Gov. Janet Mills is pushing in an effort to meet state climate goals, said Adam Barker-Hoyt, owner of MAC Heat Pumps in Bangor. Major heat pump brands use the refrigerant R-410A, he said, so there is no PFAS-free option now for customers.

The EPA plans to phase out hydrofluorocarbons in refrigerants, including R-410A, starting in 2025. R-410A is a blend of two chemicals, one containing PFAS, known as R-125, and one, known as R-32, that does not.

R-410A breaks down into TFA and other byproducts, according to a safety brochure by Daikin Fluorochemicals, which makes the chemical.

The phaseout will give consumers some PFAS-free options for appliances. But Maine already has more than 100,000 heat pumps installed, with the governor last year bumping up the goal to install 175,000 more by 2027. The average heat pump lasts 15 years.

“The main refrigerant that various heat pump manufacturers are moving towards is R-32, which thankfully does not contain any PFAS,” Barker-Hoyt said.

Sarah Woodbury places much of the blame for PFAS exposure on industry, saying the federal safety system is broken.

“Industry makes consumers responsible, but they should be selling safer products,” said Woodbury, vice president of policy and advocacy for Defend Our Health, a Portland-based nonprofit.

She said the PFAS water filters available now probably won’t be able to catch the smaller molecule compounds such as TFA. Mainers can advocate for change with their representatives and try to avoid obvious products with PFAS such as coated pans, waterproof makeup and stain-resistant fabrics, she said.

Carlson of Colby College said lawmakers will need to create laws to substitute PFAS-free products for those currently in use.

“We are ignoring the problem,” she said. “But the average Mainer can advocate for change.”

Lori Valigra is an investigative environment reporter for the BDN’s Maine Focus team. She may be reached at [email protected]. Support for this reporting is provided by the Unity Foundation and donations by BDN readers.

Lori Valigra, investigative reporter for the environment, holds an M.S. in journalism from Boston University. She was a Knight journalism fellow at M.I.T. and has extensive international reporting experience... More by Lori Valigra