PFAS

by Truc Nguyen

What Are PFAS and Why Are They Called Forever Chemicals?

If you have heard the term “PFAS” or “forever chemicals” in the news, you may be wondering what these chemicals actually are, where they are found, and why scientists and public health agencies are concerned about them. PFAS stands for per- and polyfluoroalkyl substances, a large family of human-made chemicals that have been used since the 1940s because they can resist water, oil, grease, heat, and stains. They have been used in products ranging from nonstick cookware and water-resistant clothing to food packaging, stain-resistant materials, cosmetics, and certain firefighting foams. PFAS are often called “forever chemicals” because many of them break down extremely slowly in the environment. Some PFAS can also remain in the human body for long periods. The important point is that PFAS are not one single chemical. They are a large group of different compounds, and researchers are still studying how individual PFAS and mixtures of PFAS may affect human health. Key Takeaways PFAS means per- and polyfluoroalkyl substances. PFAS are a large family of synthetic chemicals rather than a single substance. They are called “forever chemicals” because many PFAS are highly persistent and resist natural degradation. PFAS have been used in many consumer and industrial applications since the 1940s. People can be exposed through contaminated water, food, air, dust, and some consumer products. PFOA and PFOS are among the most extensively studied PFAS. Research has associated exposure to certain PFAS with several health effects, although the risks vary by chemical, exposure level, duration, and individual factors. PFAS can be measured in blood, but a blood test does not diagnose a disease or predict whether someone will develop a health condition. Reducing exposure is generally more practical than trying to completely eliminate PFAS from everyday life. What Are PFAS? PFAS are a group of thousands of human-made chemicals that contain carbon-fluorine bonds. These chemicals became popular because their unusual chemical properties make materials more resistant to water, oil, grease, heat, and stains. PFAS have been used in a wide variety of products and industries, including: Nonstick cookware Water-resistant clothing Stain-resistant carpets and fabrics Food packaging Some cosmetics and personal-care products Firefighting foams Industrial applications Certain manufacturing processes The U.S. Environmental Protection Agency describes PFAS as a group of manufactured chemicals used in industry and consumer products since the 1940s. There are thousands of different PFAS, although some have been studied much more extensively than others. PFAS Are a Chemical Family, Not One Chemical One common misconception is that “PFAS” refers to one specific substance. It does not. PFAS is an umbrella term covering a large family of chemicals with different structures, properties, uses, and levels of scientific evidence. Two of the best-known members are: PFAS Full name Why it matters PFOA Perfluorooctanoic acid One of the most extensively studied PFAS PFOS Perfluorooctane sulfonic acid Widely studied for environmental persistence and human exposure PFHxS Perfluorohexane sulfonic acid Detected in human blood and the environment PFNA Perfluorononanoic acid Studied in human exposure research This distinction matters because health research on one PFAS should not automatically be applied to every chemical in the PFAS family. Why Are PFAS Called “Forever Chemicals”? PFAS earned the nickname “forever chemicals” because many of them are exceptionally resistant to natural breakdown. The carbon-fluorine bond found in many PFAS is one of the strongest bonds in organic chemistry. As a result, many PFAS do not readily break down through ordinary environmental processes. That means some PFAS can persist in: Soil Groundwater Rivers and lakes Sediment Wildlife Food chains Household environments Human blood This persistence is one reason PFAS contamination can be difficult to manage. Does “Forever” Mean PFAS Literally Never Break Down? Not necessarily. “Forever chemical” is a commonly used nickname, not a statement that every PFAS molecule will literally remain unchanged forever. Different PFAS behave differently. Some can transform into other PFAS, while others can remain highly persistent for extremely long periods. The more accurate scientific description is that many PFAS are highly persistent and resistant to environmental degradation. Why Were PFAS Used in So Many Products? The same properties that make PFAS concerning from an environmental perspective are also what made them commercially useful. PFAS can provide resistance to: Water + Oil + Grease + Heat + Stains For manufacturers, those characteristics can improve product performance. For example, a material treated with a PFAS compound may be better at resisting water or grease. This explains why PFAS have appeared across such a wide range of consumer and industrial applications. The problem is that the chemical stability that makes PFAS useful can also make them difficult to remove once they enter the environment. Where Are PFAS Found? PFAS can be found in the environment and in a variety of products. 1. Drinking Water Drinking water is an important potential exposure route, particularly in communities affected by PFAS contamination. PFAS can enter water supplies through industrial activity, contaminated sites, firefighting foam, waste streams, and other sources. The EPA continues to address PFAS contamination in drinking water, including PFOA and PFOS. In May 2026, the agency proposed allowing certain water systems additional time to comply with federal PFOA and PFOS drinking-water limits. 2. Food PFAS can enter the food supply through contaminated water, soil, food-processing environments, packaging materials, and other pathways. Because PFAS are persistent and widespread, exposure is not limited to people living near a known contaminated site. 3. Food Packaging Some PFAS have historically been used in materials designed to resist grease and moisture. This is one reason PFAS have received attention in relation to fast-food wrappers, takeout packaging, paper products, and other food-contact materials. 4. Nonstick Cookware Some nonstick cookware has historically been manufactured using fluorinated chemistry. However, the presence or absence of PFAS cannot be determined simply by looking at a pan. Product formulations vary, and consumers should check manufacturer information when trying to choose PFAS-free products. 5. Water- and Stain-Resistant Clothing PFAS have been used to provide water, oil, or stain resistance to certain textiles. Examples can include outdoor clothing, footwear, carpets, upholstery, and other treated fabrics. 6. Cosmetics and Personal-Care Products Certain PFAS have been used in cosmetic formulations for properties such as water resistance, smoothness, and durability. Not every cosmetic product contains PFAS, so checking current ingredient and manufacturer information is important. 7. Firefighting Foam Certain firefighting foams, especially aqueous film-forming foams (AFFF), have historically contained PFAS. These products have been an important source of environmental contamination around some airports, military facilities, industrial sites, and firefighting training areas. How Do PFAS Get Into the Human Body? PFAS exposure can occur through multiple pathways. Common routes include: Drinking contaminated water If a water supply contains PFAS, drinking the water can contribute to exposure. Eating contaminated food PFAS may enter food through environmental contamination or food-contact materials. Indoor dust PFAS in consumer products and treated materials can contribute to household dust exposure. Consumer products Certain treated clothing, carpets, cosmetics, cookware, and other products may contain or have historically contained PFAS. Workplace exposure People working in industries where PFAS are manufactured or used may have higher exposure levels. Exposure varies widely depending on location, lifestyle, and environment. What Happens to PFAS in the Body? Some PFAS can remain in the human body for extended periods. PFAS can be measured in blood, and studies have detected certain PFAS in people around the world. However, the amount of PFAS in a person’s blood depends on: Type of PFAS Level and duration of exposure How quickly the body eliminates it ATSDR notes that some PFAS leave the body slowly over time and that people can have different levels even within the same household. Importantly, detecting PFAS in blood does not automatically mean a person will develop a disease. Are PFAS Harmful to Your Health? This is one of the most important questions about PFAS—and the answer is nuanced. Research has identified associations between exposure to certain PFAS and several health outcomes. According to ATSDR, studies have found associations with: Increased cholesterol levels Lower antibody response to some vaccines Changes in liver enzymes Pregnancy-induced hypertension and preeclampsia Small decreases in birth weight Kidney and testicular cancer (associated with PFOA exposure) Health risk depends on many factors, including the specific PFAS, exposure level, duration, and individual differences. Does PFAS Exposure Mean You Will Get Sick? No. PFAS exposure does not guarantee disease. Research is complex because: There are thousands of PFAS People are exposed to mixtures Exposure levels vary widely PFAS behave differently in the body Long-term effects are still being studied So scientists generally describe associations and potential risks, not direct cause-and-effect in every case. PFOA vs. PFOS: What's the Difference? PFOA and PFOS are two of the most widely studied PFAS. PFOA Used in industrial applications and widely studied for persistence and potential health effects. PFOS A highly persistent PFAS detected in the environment and human blood. Both have been heavily researched and regulated, but they represent only a small portion of the broader PFAS family. Can You Test for PFAS? Yes. PFAS can be measured in blood. However, PFAS testing is not a standard medical diagnostic test. A blood test can measure the concentration of certain PFAS, but: It does not diagnose disease or predict future health outcomes. ATSDR states that PFAS blood testing cannot identify current or future health problems or provide treatment guidance. What a PFAS Blood Test Can Tell You Which PFAS were measured The level detected in blood Comparison to population averages (in some cases) What It Cannot Tell You Whether PFAS caused symptoms Whether you will develop disease The exact source of exposure What treatment you need Who Might Consider PFAS Testing? Testing may be considered if there is: Known contamination in drinking water Occupational exposure concerns Environmental exposure near contaminated sites Participation in research studies A healthcare professional can help interpret whether testing is appropriate. How Can You Reduce PFAS Exposure? PFAS are widespread, so the goal is reduction, not perfection. 1. Check drinking water quality Especially important for private wells or known contamination areas. 2. Choose PFAS-free products when possible Look for verified PFAS-free labeling when available. 3. Be aware of product claims “Waterproof” or “stain-resistant” does not always mean PFAS-free. 4. Reduce household dust Regular cleaning can help reduce indoor exposure pathways. 5. Focus on major sources Identify the most likely exposure routes rather than trying to eliminate all PFAS. Can You “Detox” PFAS? Be cautious of products claiming to remove PFAS from the body. There is no proven consumer detox method that eliminates PFAS. Some PFAS leave the body slowly over time, but this varies by chemical and individual. A more evidence-based approach is: Identify exposure sources Reduce avoidable exposure Consult healthcare professionals when needed Use testing appropriately Interpret results in context Why PFAS Testing Is Still Useful Even though PFAS testing is not diagnostic, it can provide exposure insight. For some people, understanding whether PFAS are present in their blood can help guide conversations about environmental exposure and risk reduction. ATSDR also provides tools that estimate exposure based on water levels, but these are not substitutes for medical diagnosis or treatment decisions. PFAS vs. “Forever Chemicals” PFAS and “forever chemicals” refer to the same general group. PFAS = scientific term Forever chemicals = common nickname The nickname highlights persistence, but not all PFAS behave identically. Why Are PFAS a Growing Concern? PFAS are widely studied because: They are widely used They are highly persistent They are found in people and the environment globally ATSDR reports that nearly all people in the U.S. have measurable PFAS in their blood, though levels of some older PFAS have declined over time. What Is Being Done About PFAS? Regulatory agencies, researchers, and manufacturers are actively working to: Reduce PFAS in drinking water Study health effects Develop safer alternatives Improve cleanup technologies The EPA continues to update PFAS guidance and regulations as new science emerges. Frequently Asked Questions About PFAS What does PFAS stand for? Per- and polyfluoroalkyl substances. Why are PFAS called forever chemicals? Because many PFAS are highly resistant to breaking down in the environment. Are PFAS in drinking water? Yes, in some locations depending on contamination sources. Can PFAS be tested in blood? Yes, but it is an exposure test, not a diagnostic test. Do PFAS cause disease? Research shows associations with some health outcomes, but risk depends on many factors. Can PFAS be removed from the body? There is no proven detox method; some PFAS leave the body slowly over time. Should everyone get tested? Not necessarily—testing is most useful in specific exposure situations. The Bottom Line PFAS are a large family of human-made chemicals used for decades in many everyday products. They are called forever chemicals because many persist in the environment and can remain in the human body for long periods. While research has linked certain PFAS exposures to health effects, the science is still evolving, and risk depends on many factors. The most practical approach is not fear or elimination, but awareness, exposure reduction, and informed decision-making—including understanding what PFAS testing can and cannot tell you.