One label. Different chemistries, uses and concerns. Look closer at the molecules behind the conversation.
The PFAS conversation crosses science, industry, health and the environment. This is a place to slow down, see the differences, and follow the evidence.
TheTruthAboutPFAS.org writes everything here and pays its own costs. No company funds it. We also take a position: PFAS rules should follow the evidence for each chemistry and use, not one label. Read where we stand. Companies that make or use fluorinated chemistry, in any industry, can sign their name to the content for free, and they have a commercial interest in how PFAS are regulated. That's why every claim here links to a primary source you can check yourself.
The label starts with the structure.
Under the OECD’s 2021 definition, PFAS contain at least one fully fluorinated methyl (–CF₃) or methylene (–CF₂–) carbon atom, with a few noted exceptions. Read the definition ↗
A structural definition groups substances. It does not, by itself, describe every property or use of each one. OECD terminology report
The highlighted –CF₂– group meets the OECD structural criterion.
Five groups, chosen to show the range. Explore the structure, then follow the questions it raises. OECD group guide ↗
Carboxylic acid fragment · one example of the group
OECD structure guide ↗
PFOA and PFOS are well-studied examples of this group. Their evidence matters—and the details of other acids still need to be examined. EPA health evidence ↗
PTFE-type backbone fragment · not all polymeric PFAS
OECD structure guide ↗
Fluoropolymers and side-chain fluorinated polymers are distinct kinds of materials. The finished polymer is one part of the assessment. OECD polymer life cycle ↗
Perfluoropropane and a separate PFPE fragment
PFC structure ↗
An oxygen link distinguishes a perfluoropolyether from a perfluorocarbon. Their evidence should be distinguished too. OECD group guide ↗
Pentafluoroethyl methyl ether · one HFE example
Molecular structure ↗
A family name is a starting point. Atmospheric behavior and breakdown pathways depend on the exact compound. OECD group guide ↗
Olefin and ketone examples · different molecules
Ketone structure ↗ Olefin structure ↗
Some compounds break down relatively quickly in air. Some form persistent TFA; a short lifetime of the original molecule does not settle the fate of its products. Arp et al. · TFA evidence ↗
Other PFAS, including precursors that can transform into acids, also matter. OECD terminology ↗
PFAS appear in materials and processes across many industries, from heart stents to chipmaking. The role changes with the chemistry—from surface treatments and solid components to gases and working fluids. Explore the documented uses ↗
Layers separated for explanation
Some PFAS provide water, oil or stain repellence in textiles and coatings. That useful surface also raises questions about release during use and disposal.
Repellent finishes help fabrics, upholstery, paints and coatings shed water, oil and dirt. Glüge et al. ↗
What happens to the treatment over the product’s life?
Semiconductor and circuit assembly
Documented uses include semiconductor manufacturing, circuit boards and wire insulation. Process chemicals and solid components need different assessments.
Chipmaking uses fluorinated photoresists, anti-reflective coatings and etching agents to pattern circuits on silicon wafers. Glüge et al. ↗
Is the substance part of the product, or part of making it?
Tubing and material cutaway
Fluoropolymers are used in stents, vascular grafts, catheters, guidewires and pacemaker leads. How a device contacts the body matters to its assessment.
They give devices lubricity, electrical insulation and long-term stability in the body. FDA says no other materials currently perform the same roles, and it has found no reason to restrict their continued use in devices. FDA ↗
What material is used, and how does the device contact the body?
Exploded energy-storage assembly
Documented uses include seals, cable insulation and battery materials. Performance in the product is one part of a life cycle that also includes production and waste.
Fluoropolymers serve as fuel-cell membranes and lithium-battery electrode binders, and fluorinated materials appear in solar panels and wind-turbine blade coatings. Glüge et al. ↗
What happens during production, service and disposal?
Foam blanket and surface-active molecules
Fluorinated surfactants have been used in foams for fuel fires. Their environmental releases are a major reason this use faces restrictions.
They lower water’s surface tension, so the foam spreads a film across burning fuel. Glüge et al. ↗
Where can the substance go after the foam is used?
A closed heat-transfer loop
Some fluorinated gases and liquids move heat in refrigeration and cooling systems. Emissions, atmospheric breakdown and end-of-life handling depend on the substance and the system.
Low flammability, heat conductivity and electrical insulation make them useful as refrigerants, transformer coolants and heat-transfer fluids. Glüge et al. ↗
What is in the system, and what leaves it?
Some PFAS persist, travel and build up in people. Others break down in days, stay where they are or leave the body quickly. Following each substance through its life cycle shows which is which. ECHA’s assessment ↗
The concernMany PFAS resist breakdown; some transform into persistent products.
The other sideSome break down in days. The C6 fluoroketone used as a fire-suppression fluid breaks apart in sunlight within 4–14 days, forming only about 0.6% of a persistent acid in lab tests. Jackson et al. 2011 ↗
The concernSome PFAS travel through water, soil or air beyond the point of release. Mobility · ECHA ↗
The other sideSolid fluoropolymers such as PTFE have negligible water solubility, so they don’t move through groundwater the way soluble PFAS acids do. Korzeniowski et al. 2023 · manufacturer authors ↗
The concernSome PFAS accumulate in people and animals. It depends on the substance and exposure. Bioaccumulation · EPA ↗
The other sideOthers leave the body quickly. In exposed workers, PFBA’s blood half-life was about three days and PFBS’s about 26 days, compared with about five years for PFOS. PFBA ↗ PFBS ↗ PFOS ↗ All three studies by 3M authors
The concernSome fluorinated substances form persistent products, including TFA. Transformation · Arp et al. ↗
The other sideSome barely change. Finished fluoropolymers are described as thermally, chemically and biologically stable in use. Other scientists note that their manufacture and incineration can still release other PFAS. Korzeniowski et al. 2023 · manufacturer authors ↗ Lohmann et al. 2020 ↗
The concernExposure can come from contaminated water, food, dust, air or work with PFAS-containing materials. Exposure · EPA ↗
The other sideExposure needs a route. FDA reports no evidence that fluoropolymers in medical devices have harmful public health effects. FDA ↗
An honest conversation starts with the concerns that are well founded.
The whole story includes the chemistries that don’t fit the headlines.
Some PFAS have caused real harm. Others do jobs that are hard to replace. Telling them apart is the point.
Now look at one applicationIn two-phase immersion cooling, a dielectric fluid boils at hot components. Vapor condenses, and the liquid returns to the bath. Boiling and condensation · Wu et al., 2025 ↗
Real systems differ in how much fluid they lose. Ask for measured emissions, maintenance practices and end-of-life handling in the supplier checklist.
A useful application still needs a full assessment of the fluid, the equipment and the alternatives.
The fluid boils at the hot chip surface. The change from liquid to vapor absorbs heat.
Vapor moves above the liquid bath toward the cooling coil.
At the cooling coil, vapor gives up heat and condenses back into liquid.
Condensed fluid drips back into the bath, ready to move through the cycle again.
Follow the loop: fluid boils at the chips, vapor rises, condenses on the coil, and returns to the bath.
Immersion cooling isn't new
The Cray-2 supercomputer, introduced in 1985, immersed dense stacks of circuit boards in a non-conductive fluorinated liquid. Today's two-phase systems start from the same idea: put the electronics in the fluid. Source
NASA's Cray-2 at Ames Research Center, 1987. Photo: NASA / Wade Sisler, public domain, via Wikimedia Commons.
For a coating, a medical component, a refrigerant or a cooling fluid: ask for evidence about the exact substance and the way it will be used.
Ask for the substance identity, formulation, and applicable PFAS definition.
Ask for persistence, transformation products, toxicity and exposure data.
Ask about releases during manufacture, use, maintenance and end of life.
Compare the evidence, performance and tradeoffs for the actual application.
Take the detailed checklist to your next supplier meeting. Ask every supplier, including any that sign this site.
Download the checklistLast reviewed September 27, 2026
Some proposals would regulate PFAS as one broad group. Here is the case for that approach, where we think it goes too far, and the rules as they stand today.
ECHA’s risk committee concluded in March 2026 that PFAS are highly persistent, travel long distances and contaminate groundwater and soil, and that some cause serious health effects such as cancer and reproductive harm. Scientists who favor a class approach argue that high persistence alone is reason enough to manage PFAS together, because releases build up faster than thousands of substances can be tested one by one.
A pacemaker lead and a firefighting foam share a structural feature, but not how they are used, what they release or who is exposed. For some medical devices, FDA says no other materials can yet do the job. Fluoropolymer manufacturers have published reviews arguing that most fluoropolymers meet “polymer of low concern” criteria; other scientists dispute this, pointing to releases during manufacture and disposal. The essential-use concept offers a way to separate critical uses without alternatives from uses that can change sooner. ECHA’s socio-economic committee has also said targeted exemptions are needed where alternatives aren’t available.
ECHA’s risk committee adopted its final opinion in March 2026. Its socio-economic committee is assessing consultation responses, with a final opinion expected by the end of 2026. The European Commission and EU countries decide the eventual restriction.
ECHA’s consultation update ↗The Commission adopted a separate PFAS firefighting-foam restriction in October 2025. Its first requirements apply in October 2026; transition periods differ by use. This rule is separate from the broader proposal.
Read the adopted regulation ↗EPA’s PFAS reporting window is scheduled to begin 60 days after the forthcoming rule revision takes effect, or January 31, 2027, whichever comes first. This reporting rule is not a general ban on PFAS.
EPA’s April 2026 final rule ↗Many PFAS do jobs that matter in everyday life, from medical devices to the chips in a phone. Others have caused real harm. We think rules should tell them apart.
This is the view of TheTruthAboutPFAS.org, and companies that sign on put their name to it. Signatories have a commercial interest in how PFAS are regulated. If you think we have something wrong, tell us why.
PFOA, PFOS and releases from firefighting foams have well-documented health and environmental effects. Strict limits and cleanup should continue. EPA ↗
Assess the specific substance and use, including persistence, emissions and breakdown products such as TFA, rather than the label alone.
Where no alternative exists yet, as FDA says of some medical devices, keep the use and require tight emission controls while it continues. Essential use ↗
Where evidence is missing, fund the testing and say so plainly. Don’t assume the worst or the best.
No. The OECD definition identifies a structural feature, not a single substance or a single set of effects. PFAS include different small molecules and polymers. Their properties depend on the full structure. OECD terminology report ↗
No. Under the OECD’s 2021 definition, the qualifying feature is a fully fluorinated methyl or methylene carbon. Some other fluorinated chemicals do not have that feature. Legal definitions can differ, so identify which definition you are using. Read the definition ↗
No. Exposure to certain PFAS is linked to harmful health effects. Differences help identify the evidence and controls that are needed; missing data should remain a visible uncertainty. EPA’s health evidence ↗
It answers only part of it. Some substances form persistent transformation products. Ask what is formed, where it goes and what is known about its effects. Research on TFA and its precursors ↗
Rules depend on the substance, use and jurisdiction. The EU already restricts certain PFAS and has adopted a firefighting-foam restriction with phased dates; a broader proposal is still being evaluated. In the US, EPA’s TSCA rule requires reporting, rather than imposing a general ban. Check current rules for the exact product and place of use, starting with the policy sources above.
We don’t think so. High persistence is a real, shared concern, and it is the main reason regulators consider a group approach. But hazard, use and releases differ widely, and some uses have no alternative yet (see the evidence). ECHA’s own committees support targeted exemptions where alternatives aren’t available. We argue for strict action on proven harm and decisions based on the evidence for each chemistry and use. Read where we stand.
TheTruthAboutPFAS.org writes the content and pays its own costs. No company funds the site. Companies that make or use fluorinated chemistry, in any industry, can sign their name to the content. Signing is free, and signatories have a commercial interest in how PFAS are regulated. The site also argues for a position on regulation, set out in where we stand. If you spot an error, tell us so we can correct it.
A plain-language reference for anyone who makes, buys or regulates products with fluorinated chemistry.
Companies that make or use fluorinated chemistry, in any industry, can sign their name to the content on this site to show they stand behind it. Signing is free, and no company pays for the site.
Companies will be listed here by name as they sign on.
The conversation gets better when the chemistry gets clearer.
