The Environmental Working Group’s David Andrews outlines why he believes chemicals called per- and polyfluoroalkyl compounds should be regulated as a class. This is part of a point-counterpoint series paired with one from the American Chemistry Council’s Jessica Bowman.
In 1968, a scientist named Donald Taves discovered that samples of his own blood contained a distinct form of fluoride, which he later surmised was widespread in people because of the extensive use of organic fluoride-based compounds in consumer products. He was right: Today these fluorinated chemicals, or PFAS, are detected in nearly every person on Earth.
More than a hundred studies, many of them conducted in contaminated communities, have linked two members of this chemical family—PFOA, formerly used to make DuPont’s Teflon, and PFOS, formerly an ingredient in 3M’s Scotchgard and firefighting foam—to cancer and other serious health problems.
The Environmental Protection Agency’s PFOA advisory says: “Human epidemiology data report associations between PFOA exposure and high cholesterol, increased liver enzymes, decreased vaccination response, thyroid disorders, pregnancy-induced hypertension and preeclampsia, and cancer (testicular and kidney).” For PFOS, EPA says the human data was associated with “high cholesterol, thyroid disease, immune suppression, and some reproductive and developmental parameters, including reduced fertility and fecundity.”
And a 2010 research article on over 2,000 participants in the journal Environmental Health Perspectives found: “This exploratory cross-sectional study is consistent with other epidemiologic studies in finding a positive association between PFOS and PFOA and cholesterol.”
On the immune system, a 2018 Environmental Health article stated: “Only in the last 10 years or so has environmental health research focused on the PFASs and revealed important human health risks, e.g., to the immune system.”
Study author Philippe Grandjean notes that the “first prospective study assessing children’s antibody responses to routine childhood immunizations reported in 2012 that a doubling in exposure to PFOS and PFOA was associated with an overall decrease by up to 50% in the specific vaccine antibody concentration.”
And David Melzer and colleagues at the University of Exeter found that in a study of over 3,900 Americans: “Higher concentrations of serum PFOA and PFOS are associated with current thyroid disease in the U.S. general adult population.”
PFAS chemicals contaminate the drinking water supply of an estimated 110 million Americans according to an Environmental Working Group (EWG) analysis of summary level testing data from over 1,000 public water systems. Their stability and resistance to breakdown in the environment has earned PFAS the nickname of “forever chemicals.”
Assess PFAS as a Class
PFOS and PFOA have been phased out in the U.S., but the problem of PFAS contamination has only worsened. The past two decades have seen an alarming increase in the number of new PFAS chemicals in use, and the latest research suggests that many of them may also harm human health. To protect public health and the environment, the multitude of PFAS chemicals should be assessed and regulated, not one by one, but as a class. Yet the federal government has dragged its feet on addressing the PFAS crisis and has failed to set a single drinking water regulation for these chemicals.
PFAS chemicals never occur alone; they are present in complex mixtures within products, the environment, and people. The PFAS family is so large—numbering in the thousands, with more than 600 in active commercial use—that our current regulatory framework is woefully inadequate to assess the safety of each compound satisfactorily, especially in the absence of comprehensive toxicity data. The class approach should be straightforward, because the precedent has already been set by the Environmental Protection Agency.
The chemical industry agreed to cooperate with the EPA and end the production and use of a group of PFAS substances. This group of chemicals is often referred to as long-chain PFAS.
EPA has taken a range of regulatory actions with the goal of eliminating the use of hundreds of long-chain PFAS compounds. The question remains whether the short-chain compounds should be similarly grouped and we believe—based on similar chemical properties and the current evidence of health impacts—that they should be. Considering PFAS as a single group or class will bring faster public health protections because of the centuries it would otherwise take to tackle each short-chain PFAS through individual regulation.
For Americans, the idea that there could be PFAS chemicals in the nation’s drinking water should be alarming. If health risk limits set by Germany’s Environment Agency are compared to biomonitoring surveys of PFOA and PFAS in the U.S. population, the German criteria would suggest that more than one quarter of the American public may face health risks.
The German Environment Agency used human data to publish a safe blood serum concentration of 2 nanograms/milliliter for PFOA and 5 ng/ml for PFOS, that would avoid concerns for fertility and pregnancy, newborn weight, lipid metabolism, immune system impacts, hormone development, thyroid metabolism, and the onset of menopause. The most recent testing completed by the Centers for Disease Control in 2015-2016 show that more than one quarter of the U.S. population had PFOA at levels over 2.5 ng/ml and PFOS at levels over 8.1 ng/ml.
Three decades ago, DuPont agreed to supply an alternative source of drinking water for residents living near a DuPont Teflon factory in Parkersburg, W.Va., only when PFOA levels in water exceeded 14 parts per billion. Now the EPA says the safe level is 70 parts per trillion, or ppt. Based on a review of human health studies, independent researchers at Harvard and the University of Massachusetts have recommended 1 ppt or less.
EPA said human data “qualitatively” confirms animal data on adverse health effects, but the agency used animal data to derive the 70 ppt guideline. In doing so, the agency declined to specifically use the Harvard/University of Massachusetts study—or any other studies of people—in setting its nonenforceable health guideline of 70 ppt.
A main reason EPA has given is that because the subjects—that is, about 99% of people on Earth—“have many PFASs and/or other contaminants in their blood … their presence constitutes a level of uncertainty that is usually absent in animal studies.” In other words, the EPA is claiming that because everyone is already polluted with different PFAS compounds, the agency does not know exactly which compounds are causing which health harms and thus cannot use the human evidence of harm to set numeric regulations for them individually.
The American Chemistry Council and the trade association representing the major PFAS manufacturers nearly a decade ago agreed to virtually eliminate the use and emission of so-called long-chain fluorochemicals. They are now touting short-chain alternatives as offering the same “high-performance benefits” but with “improved environmental and human health profiles.”
GenX is DuPont’s replacement for PFOA, and the company described it as “a new industry standard for sustainable replacement technology.” But in November, the EPA released a draft toxicity assessment for GenX, finding that, at an equivalent concentration in test animals, it was substantially more potent than even PFOA. An investigation by Sharon Lerner of The Intercept reported that, after reviewing the available toxicity testing, a retired senior risk assessor in the EPA’s National Center for Environmental Assessment said: “It’s the same constellation of effects you see with PFOA.”
And the EPA has failed to require significant toxicity studies of other PFAS compounds beyond PFOA, PFOS, and GenX. In a recently published draft toxicity assessment for the compound PFBS, the EPA noted an enormous gap in safety testing data. The types of review that EPA flagged as missing include epidemiological studies; testing of developmental and immunological toxicity; a chronic mouse study; and a full two-generation reproductive toxicity study. These are exactly the types of studies that would determine whether these chemicals are as hazardous as PFOA and PFOS.
Here are two examples of how mixtures of PFAS and the lack of safety data on all but a few make it necessary to assess and regulate these chemicals as a class:
PFAS in Food Packaging
The widespread use of PFAS compounds with inadequate data extends to plastics that come into contact with food. The majority of PFAS-approved food-packaging plastics approved by the Food and Drug Administration are made using fluorotelomers, which are similar to PFOA but with a different chemical structure. These plastics are known to break down into a number of different PFAS in products and in the environment.
To argue safety, the chemical industry focused its testing on one of the expected breakdown products. A recent FDA paper indicates that in the body, the approved coating does not just become the tested chemical but also a totally different PFAS compound. This less studied PFAS compound accumulates to a greater extent in the body, increasing the potential for health harm. With a complex mixture of PFAS compounds forming in the body, approving coatings based on detailed studies of just one of those compounds is inadequate.
In 2016, a coalition of scientists from academia, regulatory agencies, and nonprofit groups detected and identified two dozen different PFAS compounds in tests of fast-food wrappers collected from restaurants. Most of the compounds have neither been thoroughly evaluated by the FDA nor adequately tested for safety by the manufacturers. These compounds were identified by matching testing results with a database of known PFAS chemicals. The known chemicals accounted for only a portion of the total fluorine in the product. What other unidentified PFAS compounds may be present in these products and what impacts they have on health is unknown.
The different PFAS chemicals found in food packaging may be due to leaching from the plastic or contamination from manufacturing and could change once in the body. The PFAS in our food could also come from contamination of the water and soil used to grow crops and animals.
PFAS in Drinking Water
It is clear that no one on Earth can escape exposure to PFAS chemicals. The U.S. Centers for Disease Control and Prevention’s periodic tests have consistently found PFAS compounds in nearly every American sampled. EWG estimates the drinking water supply of 110 million people is contaminated with one of six PFAS chemicals.
Slow development of analytical methods for detecting and differentiating among thousands of different PFAS is likely allowing other contamination to escape scrutiny. In recent tests of public water systems, a complex mixture of 10 or more PFAS was detected in nearly every system, at a combined average concentration of nearly 20 ppt.
In North Carolina’s Cape Fear River basin, GenX was detected in drinking water at around 500 ppt, but other PFAS chemicals were found at a staggering 250,000 ppt. A subsequent biomonitoring study did not detect GenX in any participants, but many other PFAS compounds were detected in every person. Current methods for detecting PFAS in water or people are limited to a few dozen compounds, and yet the range of PFAS chemicals in people and the environment is much larger.
EWG supports a scientifically grounded, risk-based approach to assessing and regulating PFAS chemicals. But to do this for each chemical, comprehensive data would be needed to differentiate individual PFAS substances from the class and consider them based on their relative potency. More significantly, for a chemical family as large as PFAS, at the current rate of EPA review, it would likely take centuries to complete these assessments. In an attempt to speed up the process, researchers at EPA have recently grouped PFAS into dozens of subsets or classes. For 75 different PFAS chemicals, toxicity testing in cells has started in collaboration with the National Toxicology Program. At some point, this line of testing may prove useful for differentiating the toxicity of subsets of PFAS, but the American people cannot wait that long.
The director of the National Institute of Environmental Health Sciences, Linda Birnbaum, agrees, stating in congressional testimony that considering PFAS as a class is the “best approach” for assessing exposure and protecting public health. This approach of assessing chemicals together has precedent.
In September, Peter Grevatt, the former head of EPA’s Office of Ground Water and Drinking Water, pointed out that the agency regulates the byproducts of disinfecting public drinking water as a group. A direct precedent for considering PFAS as a class was set in the early 2000s, when EPA initiated the phaseout of PFOA, PFOS, and other long-chain PFAS chemicals. In the 2015 proposed regulation to bar new PFOA-type chemicals from the market, EPA both explicitly listed substances subject to the rule and said the rule also covered any other members of a “group of chemical substances containing PFOA and its higher homologues.” And in 2018, Washington state banned the use of all PFAS chemicals in food contact materials.
The manufacturers of PFAS chemicals have much to gain by pushing for a chemical-by-chemical regulatory approach that takes decades for each substance. The one-by-one approach ensures that the hundreds of commercially used PFAS chemicals are unlikely to ever be regulated, because attempting to regulate or restrict even a few will monopolize the agency’s resources and limit public involvement.
PFAS chemicals are big business, used in making common, everyday products like nonstick pans, stain-resistant fabrics, waterproof clothing, fast-food wrappers, microwave popcorn bags and even cosmetics. With more than 600 PFAS chemicals already in use, the tap should be turned off, and no new PFAS allowed on the market. Currently the nation needs to tackle the enormous task of determining the extent of PFAS contamination and cleaning up the mess caused over the past decades. Allowing additional understudied PFAS on the market will just complicate efforts to safeguard health.
The bottom line: A single-chemical approach to assessing and regulating PFAS chemicals is just not possible. The naive assumption that PFOA and PFOS were safe, and the subsequent voluminous scientific evidence to the contrary, has tarnished the entire family of PFAS chemicals. In future decades, we may well find that some of the newer generation of PFAS chemicals are of lower concern for human health. But the burden of proving the safety of any PFAS chemical must lie with the chemical industry.
Without their consent, people have been made into test subjects for PFAS chemistry. This must end. Regulating PFAS chemicals as a class is the only way to protect public health.
This column does not necessarily reflect the opinion of The Bureau of National Affairs, Inc. or its owners.
David Andrews is a senior scientist at the Environmental Working Group, which has been studying PFAS chemicals since 2001. For the past decade David has been working to educate consumers, move markets toward safer chemistries, and protect public health. He holds a Ph.D. in chemistry from Northwestern University.
To read arguments contending PFAS should not be regulated as a class, please see the Insights article by the American Chemistry Council.