GenX PFAS Toxicity Assessment By EPA – Are Businesses At Risk?

Oct 25, 2021 | Environmental, PFAS

Earlier today, the EPA released its final human health toxicity assessment for GenX chemicals, part of the family of PFAS that have received substantial attention in the media in recent years. The GenX PFAS toxicity assessment is one of the key goals of the EPA’s PFAS Strategic Roadmap released late last week, and it is undoubtedly timed to reinforce the EPA’s statements that it is committed to meeting the deadlines set in the Strategic Roadmap. Regardless of the timing, though, the findings and dose response information contained in the toxicity assessment are eye-opening findings that for the first time squarely place GenX squarely in the EPA’s target sights. Any company that used or currently uses GenX chemicals absolutely must pay attention to the EPA’s assessment and must incorporate GenX considerations into compliance programs in order to avoid significant financial disruption.

What Are GenX Chemicals?

GenX chemicals are part of the PFAS class and are used to make high-performance polymers that are utilized in manufacturing processes. GenX were introduced by DuPont in 2009 to replace PFOA as part of DuPont’s agreement to voluntarily phase out and cease production of PFOA. While PFOA were made using eight carbon atoms (and were commonly referred to as “long-chain”), GenX utilized only six carbon atoms (and were referred to as “short chain”). In many instances, the two chemical types were seen as virtually interchangeable from a manufacturing and product use standpoint. Aside from intentional manufacturing of GenX chemicals, GenX can also be created inadvertently as a byproduct of certain manufacturing processes through the biotransformation process.

GenX have been widely used in manufacturing sectors and utilized in numerous products for around twelve years now. The EPA reports that GenX have been found in surface water, groundwater, drinking water, rainwater, and the air. While the product types that contain GenX chemicals are numerous, some of the more common applications include food packaging, paint, cleaning products, nonstick coatings, fabrics, firefighting foam, cell phones, and laptops. From an environmental standpoint, PFOA and GenX share similar biopersistence issues; however, GenX chemicals are widely recognized as more mobile than PFOA, which has led to concerns over the speed at which GenX contamination may occur.

GenX PFAS Toxicity Assessment

At over 200 pages in length, the EPA’s GenX PFAS toxicity assessment provides a great deal of scientific support for the EPA’s findings with respect to GenX. A key part of the assessment is that it directly relates to toxicity of the chemicals to human health. Similar human health toxicity assessments have only been done by the EPA for three other PFAS types – PFOA, PFOS and PFBS. While the EPA recognized that people can be exposed to GenX in several ways, the toxicity assessment only looked at oral ingestion through drinking water.

Relying substantially on animal studies involving oral exposure to GenX chemicals, the EPA’s GenX PFAS toxicity assessment concludes that GenX have several potential health effects, including on the liver, kidneys, the immune system, development of offspring, and an association with liver and pancreatic cancer, with the liver being especially susceptible to oral exposure from GenX chemicals.

Taking this into consideration, the EPA established what it calls chronic and subchronic reference doses (RfDs) for GenX chemicals. The EPA defines these terms as follows: “a reference dose is an estimate of the amount of a chemical a person can ingest daily over a lifetime (chronic RfD) or less (subchronic RfD) that is unlikely to lead to adverse health effects in humans.” The RfDs that the EPA established for GenX were as follows:

Subchronic RfD (mg/kg/day) Chronic RfD (mg/kg/day)
0.00003 0.000003

To put these numbers into context, they are lower than any of the other three PFAS toxicity assessment RfDs released to date, with the GenX numbers coming in at 100 times less than the RfD for PFBS. The EPA points out in its toxicity assessment, though, that it is currently re-assessing the PFOA and PFOS RfDs, suggesting that new RfDs for either or both may in fact be less than the GenX RfD.

Impact of GenX PFAS Toxicity Assessment On Businesses

The immediate and short-term impact of the GenX PFAS toxicity assessment is that it is merely a harbinger of much more significant regulatory action, enforcement action and litigation. The EPA’s toxicity assessment is not a binding regulation; however, as the EPA notes, the “…final assessment marks a critical step in the process of establishing a national drinking water health advisory for GenX chemicals…”, and it also provides other federal level agencies with scientific support and references for potential future regulatory action for exposure sources other than drinking water. The biggest short-term takeaway from the toxicity assessment to any business should simply be a clear announcement that the EPA intends to set a drinking water standard that includes GenX chemicals, possibly at levels much lower than previously believed.

Once the EPA sets an enforceable drinking water standard for GenX, it will have the power to pursue companies that it believes contributed to GenX environmental pollution in all fifty states. Through enforcement actions, the EPA can and will pursue alleged responsible parties for remediation costs, which, depending on the scope of pollution, can range anywhere from a few hundred thousand dollars to hundreds of millions of dollars. GenX was hailed by many in the industrial, manufacturing and consumer products markets as a seamless substitute for PFOA, and one that at the time of its introduction had not been studied publicly to determine human health effect concerns. GenX was therefore widely used across the country and globally for over a decade, and significant media attention has spotlighted concerns that the unchecked use of GenX over the last decade may have resulted in significant environmental pollution and human health impacts.

Companies that utilize GenX in consumer goods, or that utilize GenX in manufacturing in such as way that GenX may contaminate the finished product, should pay close attention to the RfDs announced by the EPA. Federal agency findings and conclusions regarding the health effects of chemicals often provides the springboard for personal injury lawsuits related to products that contain those chemicals. The glyphosate litigation is perhaps the most recent example of this phenomenon occurring.


Now more than ever, the EPA is clearly on a path to regulate GenX in the country’s drinking water. These regulations will require states to act, as well (and some states may still enact stronger regulations than the EPA). Both the federal and the state level regulations will impact businesses and industries of many kinds, even if their contribution to drinking water contamination issues may seem on the surface to be de minimus. In states that already have PFAS drinking water standards enacted, businesses and property owners have already seen local environmental agencies scrutinize possible sources of PFAS pollution much more closely than ever before, which has resulted in unexpected costs. Companies absolutely must begin preparing now for regulatory actions that will have significant financial impacts down the road.

CMBG3 Law is following judicial, legislative, administrative, and scientific developments relating to PFAS. More information about the services we can provide, including risk assessments, to ensure your business is ready for any intersection with these substances can be found on our PFAS Litigation page.

Our attorneys have been at the forefront of PFAS issues, including giving presentations as to the future waves of litigation stemming from PFAS issues. For more information, please contact the Chair of our PFAS – Toxic Torts Team: John Gardella.


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