Perfluorinated Polymers and the Path to Safer Alternatives: Re-Thinking How We Assess and Manage Polymers

As industry scrambles to address PFAS restrictions and search for alternatives, some are advocating for either the outright exclusion of perfluorinated polymers from broad restrictions or to allow for delays in implementation.  (Note: for this article, I’m generally excluding the side-chain polymers from this discussion and focusing on perfluoropolyethers and fluoropolymers).

While underlying toxicological data on perfluorinated polymers is limited, industry and regulators alike should not assume the lack of evidence of harm is synonymous with safety. The alternatives assessment community has documented several cases of regrettable substitution, many of them driven by prioritizing drop-in replacements without adequate assessment of their impacts.  

We’ve been down this road with PFAS. Remember years ago when concerns over C8 and C10-based chemistries led to replacements with “safer” shorter-chain substances? These decisions occurred because technical performance and ease of transition were prioritized over alternatives that are inherently less hazardous. Time was wasted at a significant cost to public health. Skepticism of less studied PFAS is justified.

I am confident we can find safer and sustainable alternatives to perfluorinated polymers without defaulting to other PFAS. To do this properly, we will need to fundamentally change how we evaluate the hazard and exposure of polymers.

Polymer Assessments for the 21st Century

Presently, there is no definitive, authoritative assessment by a national or global body vindicating fluoropolymers or polyfluoropolyethers from the health and environmental concerns associated with nonpolymeric PFAS. The OECD Environment Directorate recently published a report which highlights significant gaps in perfluoropolyether (PFPE) characterization, degradation potential, and release data. In short, there are more questions than answers.

Alarmingly, the report also noted that many of the PFPEs they cataloged “have rather low molecular weight, even below 1000 Da”, which challenges the argument that perfluorinated polymers are less hazardous due to their size. The assumption of high MW/low bioavailability = low hazard has been the cornerstone of many safety claims for polymers. This assumption has been oversold in the assessment community, not just in terms of PFAS. At its worst, it paints high MW polymers as benign bouncy balls springboarding off cellular membranes to ultimately float off into the ether. As a chemical assessor who has supported their fair share of hazard assessments for polymers, I am often left thinking – there has to be a better way.

The assumption of high MW/low bioavailability = low hazard has been the cornerstone of many safety claims for polymers. This assumption has been oversold in the assessment community, not just in terms of PFAS.

These assumptions are not aligned with our evolving understanding of sustainable chemistry. According to The Expert Committee on Sustainable Chemistry (ECOSChem) sustainable chemistry is a more holistic movement inclusive of not just health and safety, but transparency, equity & justice, climate & ecosystem impacts, and circularity.  The latter two are sorely missing from the status quo polymer assessments but need urgent addressing.

Images of floating plastic waste in waterways is so common in our mainstream media that it’s almost cliche. I’m also obliged to highlight the studies published this year reporting the detection of micro and nanoplastics in human testicular and brain tissues and artery plaque. The microplastics issue is not new to the environmental community, but we are in dire need of toxicologists and epidemiologists to help us articulate and quantify the impacts to human health and wildlife.

Many questions remain. What are the contributions of perfluorinated polymers and their alternatives to microplastic exposure? Where do these materials ultimately end up?  How can we design durable, functional materials and meet goals for circularity?

Our assumptions about polymer exposures are more complicated than originally thought, and it’s time chemical assessment practices adequately reflected this shift in understanding.

Functional substitutes to perfluorinated polymers are achievable

Thankfully, chemical alternatives assessment is flexible and offers an opportunity to pilot novel approaches to polymer assessments. At its core, alternatives assessment “identifies and compares potential chemical and non-chemical alternatives that could replace chemicals of concern on the basis of their hazards, performance and economic viability”.  It allows for the transparent assessment and likely trade-offs of candidate alternatives. In addition to these core tenants, added elements aligned with the concepts of sustainable chemistry can be added to the assessment.

I would argue an alternatives assessment’s scope for any perfluorinated polymer should include additional evaluations of exposure and life-cycle impacts, as outlined in the IC2 AA Guide, so the assessment of candidate alternatives can adequately address the concerns of perfluorinated PFAS across its entire lifecycle.

Given the hurdles over data transparency and disclosure, which are even more problematic for polymeric substances, I am fully aware of the challenges this poses. A well-conducted alternatives assessment is an exercise in stakeholder engagement and supply chain cooperation. As my colleague Dr. Lauren Heine has said: “It takes a lot more information to prove that a chemical is inherently safer than it does to prove that it is toxic”.

It is possible that safer alternatives to perfluorinated polymers already exist. Even if a well conducted alternatives assessment concludes there are no practical alternatives, then at the end of the day, we have a roadmap to inform innovation.

Nothing regarding PFAS has been easy. Perfluorinated polymers are no different, but we cannot default to what is easy and accessible. That is a recipe for regrettable substitution. The tools are there, we just need to use them.

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Catherine Rudisill has 20 years experience in chemical assessment and environmental health consulting with a special focus on identifying and assessing safer chemical alternatives. She is the Founder & Principal of Safer Chemistry Advisory LLC, an independent, woman-owned and operated consultancy founded in 2022.