Per- and polyfluoroalkyl substances, commonly known as PFAS, represent a class of man-made, highly fluorinated organic molecules characterized by exceptionally strong carbon-fluorine bonds. These bonds create materials with remarkable properties: resistance to chemical and physical degradation, water and oil repellency, emulsification capabilities, and high-temperature stability.
Such characteristics have made PFAS valuable across numerous industries, including common household products (non-stick cookware, personal care items, etc.), pharmaceuticals, plastics, electronics, firefighting, cosmetics, automotive, aerospace, and energy storage.
However, those same properties — and the strength of the carbon-fluorine bonds — have raised concerns about the environmental persistence of PFAS and potential impacts on human health. As a result, regulatory bodies worldwide are responding with evolving rules and restraints, and consumers are increasingly calling for alternatives.
To establish a deeper understanding of PFAS prevalence in scientific publications, we conducted systematic chemical structure-based searches within the CAS Content CollectionTM, the largest human-curated repository of scientific information. Our analysis revealed striking differences in PFAS identification based on varying regulatory definitions (See Figure 1):
- Following the Organization for Economic Cooperation and Development (OECD) 2021 definition guidelines (which include compounds containing even a single -CF₃ or -CF₂ group), approximately 24 million distinct PFAS molecules were identified within the CAS Content Collection.
- In contrast, when applying the more stringent United States Environmental Protection Agency (U.S. EPA) definition (requiring at least two -CF₂ or -CF₃ groups), the number of substances classified as PFAS decreased significantly to approximately 1.8 million compounds.
These numbers are significantly higher than the 10,000-15,000 PFAS compounds estimated to exist, and it means that far more products may be impacted by regulations or need formulation changes to achieve similar properties in their applications. By focusing on substances with established scientific or commercial relevance, we analyzed over 350,000 unique compounds appearing in more than one million scientific documents.
Despite a distinct increase in publications on PFAS mitigation or remediation over time (see Figure 2), the current volume of research is still insufficient given the widespread use and environmental impact of PFAS. It is important to note that the U.S. stands out as the most influential and proactive in terms of PFAS mitigation research, driving significant advancements in this field. The EU and China also emerge as key players, ramping up research initiatives to tackle PFAS-related challenges.
This still underscores the necessity for intensified global efforts to develop effective methods for mitigating PFAS contamination, thereby ensuring environmental safety and protecting public health. Our analysis covers the evolving regulatory landscape and PFAS prevalence in 25 major applications. We’ve identified publication trends as well as potential alternatives in various applications, based on documents in the CAS Content Collection.
Geographic shifts and commercial patterns in PFAS literature
In our analysis, we examined 1 million documents from the CAS Content Collection that referenced over 350,000 unique PFAS compounds. Temporal analysis reveals a significant upward trend in the number of journal and patent publications over the past 70 years (see Figure 3). Despite stringent global regulations, the patent-to-journal ratio of 2:3 indicates that PFAS compounds remain widely used across various industrial applications.
Our analysis of the global distribution of these publications reveals that while the U.S. remains prominent, Asian countries, particularly China and Japan, are also key centers for PFAS research and application (see Figure 4). This trend could result from the absence of stringent PFAS regulations in these regions. In addition, European countries show low patent publication numbers, suggesting a decreasing trend or reduced usage of PFAS in industries likely related to a potential selective PFAS ban in the EU.
The commercial use of PFAS in various countries was assessed by analyzing the number of patents published by various industries in these regions (see Figure 5). Notably, Japan is at the forefront of using PFAS for the commercial applications, followed by the U.S. and China. The temporal analysis in Figure 5 of the patent publications by these countries reveals that China is the only country experiencing a significant increase in PFAS-related commercial patents, while commercial use has slowed in all other countries except South Korea.
As we’ll see, these patterns reflect the widespread use of PFAS in several industries and applications and the diversity of regulatory approaches throughout geographic regions.
The changing PFAS regulatory landscape
Regulating PFAS presents complex challenges beyond simple elimination, requiring a delicate balance between reducing environmental and health risks while maintaining essential functions. The regulatory landscape is complicated by the diversity of PFAS compounds; scientific uncertainty regarding their toxicity, persistence, and bioaccumulation; and the critical role of these chemicals in sectors like healthcare, defense, and fire safety.
Additionally, practical barriers exist in the process of removing or replacing PFAS, including detection limitations, remediation costs, and a lack of suitable alternatives for some critical applications. This necessitates nuanced regulatory approaches that prioritize phasing out non-essential uses, while managing careful transitions for applications where immediate elimination would create unacceptable disruptions or safety concerns.
Different geographic areas have taken action to regulate PFAS over the last 15 years, with activity increasing in the last five years as public concerns mount over the effects of PFAS on the environment and human health (see Figure 6).
U.S. regulations
The U.S. EPA has implemented measures to selectively restrict or ban PFAS over time. In 2023, the agency introduced a new framework to establish a more rigorous review process: PFAS with negligible exposure and environmental release risk can be commercialized after receiving basic physical-chemical property data and ensuring PFAS can be disposed properly. PFAS with low, but not negligible release potential requires additional testing, such as toxicokinetic data, before manufacturing approval.
For PFAS likely to cause significant environmental releases or exposures (like spray-applied stain guards), the EPA typically prohibits commercialization until extensive testing on physical/chemical properties, toxicity, and environmental fate is completed, unless a critical military need exists.
The EPA’s 2024 PFAS Strategic Roadmap designated the two most widely used and harmful PFAS, PFOA and PFOS, as well as their salts and structural isomers, as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, commonly known as the Superfund). This designation has led to several reporting requirements and disclosure obligations for industry, property owners, and federal agencies, allowing the EPA to address more contaminated sites, take early actions, and expedite eventual cleanups.
There are also many state-level regulations that often mandate product notifications, compliance certifications for manufacturers and distributors, and outright bans on certain product categories with intentionally added PFAS. California, Maine, Washington, and others have implemented comprehensive bans on PFAS in various consumer product categories.
Companies may struggle with varying state regulations, but these actions are driving the market away from PFAS chemicals despite the lack of strong federal laws. As public concern about these persistent "forever chemicals" increases, more states are proactively addressing the issue rather than waiting for federal intervention.
EU PFAS regulations
The European Union (EU) generally has more stringent restrictions on PFAS than the U.S. under the Stockholm Convention. Member states have also enacted partial bans, such as Denmark, where the import and sale of clothing, footwear, and their waterproofing agents containing PFAS will be banned in most cases beginning July 2026.
The European Chemicals Agency (ECHA) estimates that, if current practices continue in a similar manner, 4.4 million metric tons of PFAS will be discharged into the environment over the next three decades. This scenario poses substantial risks to environmental and public health due to the persistent nature of PFAS emissions. As a result, in 2023, the ECHA collaborated with European authorities from Denmark, Germany, the Netherlands, Norway, and Sweden to put forward a proposal that would effectively ban all PFAS fitting the OECD definition (with certain exemptions) in Europe.
EU agencies have received thousands of comments regarding the proposed legislation, including concerns over potential job losses and supply chain disruptions. As of this writing, deliberations are continuing about a potential ban and any economic implications.
Asia-Pacific regulations
The Stockholm Convention influences much of the PFAS regulations in the Asia-Pacific region. Countries including China, Japan, South Korea, Australia, and New Zealand have prohibited or restricted PFAS substances. However, the regulatory landscape in these countries continues to evolve, with several of them adopting progressive measures that mirror approaches taken in the U.S. and EU.
PFAS usage patterns by application
Overview
In our analysis of the CAS Content Collection, we classified publications into various applications based on CAS’s topical sections. We narrowed our focus to 25 major applications based on their high patent-to-journal ratio (see Figure 7).
From there, we conducted an in-depth analysis of chemical substance and scientific concept relationships across 10 selected applications, chosen based on their distinctive fluorine content profiles and higher patent/journal publication ratios.
Plastics
PFAS are incorporated into various plastic formulations to impart critical performance properties, including enhanced chemical resistance, thermal stability, and reduced friction. As seen in Figure 8, small molecules and polymers are the predominant PFAS substance classes.
In conventional plastics, PFAS functions as mold release agents and anti-blocking additives that prevent adhesion between plastic surfaces during manufacturing. PFAS have been used extensively in plastic food packaging, where they’ve been found to migrate from into foodstuffs, raising concerns about human exposure. Numerous alternatives already exist for food packaging, such as polyethylene and silicone resins and oils.
To discover the functions of frequently used PFAS molecules in plastics, we analyzed the co-occurrence of key scientific concepts and PFAS substances. As Figure 8 shows some PFAS molecules, such as 1107-00-2 (4,4-(hexafluoro-isopropylidene)diphthalic anhydride) and 341-58-2 (2,2’-bis(trifluoromethyl)-4,4’-diaminobiphenyl) are featured prominently in publications discussing plastic films and optical imaging devices. Others like 9011-17-0 (hexafluoropropylene-vinylidene fluoride copolymer) and 25067-11-2 (Hexafluoropropylene-tetrafluoroethylene copolymer) appear across multiple application concepts such as carbon black incorporation, plastic films, coating materials, and membranes.
Other applications
In our analysis of PFAS-related literature in the CAS Content Collection, we examined numerous industrial applications including agrochemical bioregulators; energy storage and conversion; photography and radiation; electronics, specifically PFAS usage in semiconductor fabrication and battery technologies; coatings and inks; rubber and synthetic elastomers; and refrigeration and separation substances. Small molecules are one of the main substance classes across these applications, along with polymers and salts. We also analyzed PFAS substances in the consumer categories essential oils and cosmetics and textiles and fabrics. PFAS are used in these applications extensively, but these categories also have the most viable replacement materials.
It’s important to note that pharmaceuticals are numerically the most prevalent application in the literature. We found nearly 560,000 documents that include a PFAS reference relating to various drugs, drug carriers, drug delivery systems, and the study of their functions. However, PFAS molecules in pharmaceutical applications generally feature different chemical structures than other long-chain PFAS molecules, although they technically meet the OECD definition of PFAS. Pharmaceuticals are also being classified as “essential use” of PFAS molecules because of their critical role in medications and current lack of non-fluorinated alternatives.
For an in-depth discussion of these applications, please download the full-length report.
Challenges in phasing out PFAS
Our full-length report provides an unprecedented analysis of PFAS, offering a data-driven perspective that transforms our understanding of this critical chemical class. Our comprehensive examination of the CAS Content Collection reveals that the PFAS universe is substantially larger and more structurally diverse than commonly understood in regulatory and scientific discourse, with significant implications for policy development and transition planning.
The structural-function relationships uncovered in our analysis demonstrate why PFAS have become so deeply integrated across industries — their unique properties are deliberately engineered through specific fluorine patterns tailored to application requirements. This explains their technical value and the challenge of finding suitable alternatives.
Our global regulatory analysis reveals a fragmented landscape evolving at different rates and with different approaches. This creates a complex compliance environment for multinational operations and suggests that regional manufacturing and innovation shifts are likely as companies adapt to varying requirements. The contrast between the EU's comprehensive approach, for example, and the more selective U.S. federal strategy highlights the fundamental tension between precautionary principles and risk-based regulation in addressing chemicals of emerging concern.
The future PFAS landscape will be shaped by the interplay between technical innovation, regulatory evolution, and market transformation. Organizations that develop comprehensive, application-specific strategies based on structural understanding of their PFAS portfolio will be best positioned to navigate this complex transition. Those that proactively engage in regulatory discussions with evidence-based assessments of technical feasibility will help shape more effective policy approaches that protect environmental and public health while preserving critical technologies.
