The Environmental Protection Agency’s (EPA) division, which is responsible for protecting the public from toxic substances, is operating under a new “forever chemicals” definition of PFAS that excludes some of their common compounds.
The new “working definition” established by the Office of Pollution Prevention and Toxics is not only at odds with much of the scientific community, but is narrower than that used by other EPA divisions.
The narrower definition excludes, among other things, chemicals in medicines and pesticides, which are generally defined as PFAS. The EPA also cited the narrower definition in December when it refused to take action on a PFAS contamination found in North Carolina.
PFAS, or per- and polyfluoroalkyls, are a class of approximately 12,000 compounds most commonly used to make products water, dirt and grease repellent. They are found in thousands of products across dozens of industries and have been linked to cancer, birth defects, reduced immunity, high cholesterol, kidney disease and a host of other serious health problems. They are referred to as “forever chemicals” due to their longevity in the environment.
The discussion within EPA comes as the agency faces increased pressure to largely restrict the entire class of chemicals, and critics say the change benefits chemical manufacturers, the Department of Defense and industry.
“There is a real difference between the definition that industry uses and the definition that the international scientific community uses, and unfortunately the definition that the EPA Toxic Bureau uses is much more similar to that used by industry,” said Linda Birnbaum , a former EPA scientist and head of the National Toxicology Program.
An EPA official, who spoke to the Guardian on condition of anonymity, said the new definition was developed about a year ago and discussions about it are ongoing.
The problem comes to light when the new managers of the EPA’s chemicals division are accused by whistleblowers that management has changed risk assessments to make PFAS appear less toxic.
The EPA did not immediately respond to questions, but an agency document obtained by the Guardian said the new definition “focuses on PFAS that are considered to be of very high concern due to their persistence and potential for environmental presence and human exposure.” will”.
Researchers say the international scientific community is embroiled in a debate over the definition of PFAS that focuses on chemical structure. PFAS are called “forever chemicals” because their fluorinated atoms prevent them from fully degrading.
The most widely used, comprehensive definition proposed by the Organization for Economic Co-operation and Development (OECD) defines any chemical with a fluorinated carbon atom as a PFAS. That could include tens of thousands of chemicals on the market.
However, the EPA Toxic Office has written a “working definition” that “requires at least two adjacent carbon atoms, with one carbon being fully fluorinated and the other at least partially fluorinated.” It covers approximately 6,500 PFAS, and the EPA uses this definition in its recently launched “national testing strategy,” which serves as a roadmap for its attempt to curb PFAS pollution.
Beyond chemicals in pesticides and pharmaceuticals, the narrower definition excludes some refrigerants and PFAS gases. Some of the excluded PFAS compounds turn into highly toxic chemicals, such as PFOA and PFOS, when they are broken down in the environment or metabolized by the human body. And the production of some excluded PFAS requires the use of other, more dangerous PFAS compounds.
“How do you say something isn’t PFAS when it becomes PFAS after being metabolized by the body or undergoing changes in the environment — that just doesn’t sit well with me,” Birnbaum said.
Part of the definition debate also revolves around the “persistence” of chemicals. The vast majority of chemicals with a fully fluorinated carbon atom are not fully degraded, and some of these compounds are accumulating at worrying levels around the world, noted Ian Cousins, a Stockholm University PFAS researcher who is a co-author of articles on the subject .
“Levels are rising, but toxicity is low, so should we be concerned?” he asked. “I say ‘yes’ because we shouldn’t be releasing substances … that multiply in the environment and we may find a problem when it’s too late to turn back.”
Cousins and other experts say a discussion of how to narrow the definition is warranted, but the Toxic Office’s approach is too restrictive. The EPA’s Research and Development Office seems to have found a middle ground, working with a definition that includes about 12,000 PFAS compounds. Meanwhile, US Congresswoman Deborah Ross introduced legislation that would make a fluorinated carbon atom the law.
The EPA official who spoke to the Guardian said they were not involved in the discussion that preceded the definition change, but said chemists in the agency’s new chemicals division likely developed them. The staffer said the chemists likely defined the compound based solely on the chemicals’ structure, not because of the dangers they pose to human health and the environment.
The staffer said excluding some PFAS compounds was “a problem” but developing an adequate definition was “difficult”.
The impact of the definition change has already been seen in North Carolina’s Cape Fear Basin, a region grappling with decades of pollution from a PFAS manufacturing facility owned by chemical giant Chemours. A 2019 petition from a citizens’ group called on the EPA to conduct studies that would shed light on the health effects of 54 PFAS compounds found in human blood and water in the region.
In the agency’s December 2021 response, it declined to test for 15 chemicals it said “failed” to meet the Toxic Office’s PFAS definition. The citizen groups are suing, and the Justice Department and EPA are coordinating their defense with Chemours, said Bob Sussman, an environmental attorney for the groups.
The EPA wrote in its response that some of the excluded chemicals “are expected to degrade in the environment” and some become TFA, which the agency described as a “well-studied substance.” However, researchers say most substances like TFA don’t break down completely, and studies show that it accumulates in the environment and is toxic with prolonged exposure.
Critics also stressed that there was very little data on the toxicity of some excluded chemicals and that allowing the use of PFAS with little toxicological data had caused problems. The EPA reported in November that GenX, PFOA and PFOS — three common compounds — are much more toxic than previously thought, noted Kyla Bennett, a former EPA scientist who now works at Public Employees for Environmental Responsibility.
“That’s the biggest problem: The EPA just doesn’t know,” she said. “I would rather apply the precautionary principle and capture chemicals that may not deserve to be so tightly regulated than miss them [dangerous chemicals].”