Chemicals: Perfluoroalkyl and Polyfluoroalkyl (PFAS) Substances
What are PFAS?
Perfluoroalkyl and polyfluoroalkyl substances, or PFAS, are a group of chemicals made by humans. Since the 1950s, PFAS have been used in many consumer products and industrial processes. They have properties that resist heat, grease, and water. There are thousands of types of PFAS. The most common types are PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanoic sulfonic acid). View the Family Tree of PFAS (PDF).
Where are PFAS found?
While PFOA and PFOS have been phased out from their use in commercial products, they are still found in the environment from historical uses and in some firefighting foams. In addition, products are often made with other PFAS as replacements for PFOA and PFOS. These PFAS can be found in everyday products, such as:
- Cleaning products.
- Water-resistant fabrics, such as rain jackets, umbrellas, and tents.
- Grease-resistant paper.
- Nonstick cookware.
- Personal care products, like shampoo, dental floss, nail polish, and eye makeup.
- Stain-resistant coatings used on carpets, upholstery, and other fabrics.
How can I be exposed to PFAS?
The main ways people can be exposed to PFAS include:
- Drinking contaminated municipal or private well water.
- Eating fish with high levels of PFAS.
- Eating food grown or raised near places that used or made PFAS.
- Eating food packaged in material made with PFAS.
- Swallowing contaminated soil or dust.
- Using some consumer products, such as ski wax, nonstick cookware, and stain and water repellant sprays for fabrics.
How can PFAS affect health?
Scientists conduct research in both humans and animals to see how PFAS affect us.
Research studies among humans have looked at a possible link between PFAS levels in the blood and harmful health effects. However, most studies have analyzed only a small number of chemicals. Not all PFAS have the same health effects. Research suggests that high levels of some PFAS may:
- Increase cholesterol levels.
- Decrease how well the body responds to vaccines.
- Increase the risk of thyroid disease.
- Increase the risk of some cancers.
- Increase the risk of serious conditions like high blood pressure or pre-eclampsia during pregnancy.
- Lower infant birth weights (the decrease in weight is small and may not affect health).
Other research has tested PFAS in laboratory animals. Humans and animals do not always react the same way to PFAS. Scientists, though, have ways to compare the results in animals to what they would be in humans. What they learn from this process helps them decide how to protect people from harm caused by chemicals. Animal studies have found that PFAS can affect development, the immune system, and the liver.
PFAS blood tests
Most people in the U.S. have PFAS in their blood. PFAS levels are similar to low levels of other contaminants in the blood like flame retardants and plasticizers. You can have a PFAS blood test to check your levels. However, there isn’t enough research to know at what PFAS levels you should expect health problems.
If you have been exposed to PFAS and are concerned about your health, you can talk to your health care provider. You can share this information for clinicians with your provider and work together to determine the best path forward based on your unique circumstances.
What are DHS' drinking water health advisories for PFAS?
The Department of Health Services (DHS) has established drinking water health advisories for 18 PFAS.
- PFOA = 4 ng/L
- PFOS = 4 ng/L
- FOSA = 4 ng/L
- NEtFOSA = 4 ng/L
- NEtFOSAA = 4 ng/L
- NetFOSE = 4 ng/L
- PFNA = 10 ng/L
- PFHxS = 10 ng/L
- GenX (HPFO-DA) = 10 ng/L
- PFDA = 300 ng/L
- PFDoA = 500 ng/L
- DONA = 3,000 ng/L
- PFUnA = 3,000 ng/L
- PFBA = 10,000 ng/L
- PFTeA = 10,000 ng/L
- PFHxA = 150,000 ng/L
- PFODA = 400,000 ng/L
- PFBS = 2,000 ng/L
Notes:
- Units are nanograms of PFAS per liter of water (ng/L). This is equal to parts per trillion.
- In 2025, DHS provided the Wisconsin Department of Natural Resources (DNR) updated public health enforcement standard recommendations for PFOA, PFOS, PFNA, PFHxS, GenX (HFPO-DA), and PFBS. DHS uses these recommendations as drinking water health advisories for evaluating public health risk from PFAS from drinking water exposure.
- In 2025, DHS established individual drinking water health advisories for FOSA, NEtFOSA, NEtFOSAA, and NEtFOSE.
- DHS established the remaining health advisories as public health groundwater enforcement standard recommendations in 2019 and 2020.
- Our groundwater standards page has more information on the recommended groundwater standards and the groundwater standards process.
Hazard index
DHS also uses a hazard index approach to assess the risk from mixtures of PFAS. This approach accounts for many types of PFAS that cause similar health effects when they are found together. Our PFAS Hazard Index animated video explains how the hazard index works. Video in Spanish. Video in Hmong.
DHS' February 19, 2025, letter to the DNR (PDF) describes the technical aspects of our PFAS hazard index approach in more detail.
How can I protect myself and my family from PFAS?
Because PFAS are so common in our environment, there is no easy way to completely avoid them. There are some simple actions, though, that can limit our contact with them.
Consider testing for PFAS if you live near an area of known PFAS contamination.
- Check the DNR's PFAS Interactive Data Viewer to see if PFAS has been found near you.
- If you live near a site of PFAS contamination, connect with your local municipality and the appropriate DNR contact to learn about available resources, including testing.
If you choose to test your own water, use a Wisconsin certified lab.
If you have tested for and found PFAS in your drinking water, use this online PFAS Assessment Tool to evaluate the health risk from PFAS in your drinking water and determine whether you need a safer water source.
- If the PFAS levels in your water are high, use a different water source for drinking, making foods that take up a lot of water (like rice, oatmeal, and gelatin), and making baby formula.
- Options include bottled water that has been purified or filtered and water from a source that has been tested for PFAS and does not contain PFAS above DHS' health advisories.
- You can use your water for bathing, brushing teeth, washing dishes, doing laundry, and filling your swimming pool. To lower the chance of drinking small amounts of PFAS, remind swimmers not to swallow pool water.
- Find a long-term solution. Options include installing a certified treatment device and drilling a new well.
- Water from a treatment system certified by ANSI/NSF Standards 53 or 58 to reduce PFAS. Our Reducing PFAS in Your Drinking Water Guide, P-0301 has information on which devices work best.
- The DNR well compensation grants provide funds to address public health hazards in private wells.
Our PFAS in Private Wells fact sheet, P-03212, has these steps in printable format.
Our PFAS and Backyard Gardening guide, P-03111 has ways to reduce PFAS exposure in your garden in areas with known or suspected PFAS contamination. It also describes how plants can take up PFAS.
The DNR's Eating Your Catch—Making Health Choices page lists the fish consumption advisories across the state. These advisories are in place to reduce the risk of health effects from chemicals that can build up in fish tissue, such as polychlorinated biphenyls, mercury, and PFAS.
PFAS do not easily enter the body through the skin. This means it’s usually okay to swim in surface water—which includes lakes, rivers, and ponds—even if it has PFAS. Despite this, there are still important ways to avoid swallowing PFAS by accident:
- Keep water out of your mouth—If water gets in your mouth, don’t swallow it. Besides PFAS, surface water can have algae, bacteria, viruses, and other harmful substances. They can pose a health risk for people and pets if they swallow them.
- Avoid foam—Kids and pets should avoid foam since they are more likely to swallow it by accident. Foam found in surface water can come from natural causes, pollution, or both. Natural foams can have algae, bacteria, parasites, and decaying organic matter. Pollution foams can have chemical contaminants, such as PFAS.
- Shower after swimming—Rinse off after swimming or touching surface water. Always wash your hands with soap and water before touching food.
- Rinse your pets—Don’t forget to clean your pets after they swim in surface water. Don’t let them lick foam or algae off their fur.
Soil that has PFAS can come into your home from the outside. Dust also can have PFAS from common household products. Examples include stain-resistant carpeting or clothing that repels water. Vacuuming using a high efficiency particulate air (HEPA) filter reduces the amount of dirt and dust in your house.
Consumer products that may have PFAS include:
- Cleaning products.
- Nonstick cookware.
- Paints, varnishes, and sealants. Follow directions carefully for safe use of these products.
- Personal care products like shampoo, dental floss, and cosmetics like nail polish and eye makeup.
- Some grease-resistant paper, fast food containers or wrappers, microwave popcorn bags, pizza boxes, and candy wrappers.
- Stain-resistant coatings on carpets, upholstery, and other fabrics.
- Water-resistant clothes.
There have been recent federal efforts to remove PFAS from consumer products. These efforts have decreased how many people are exposed to PFAS from these products. However, some products still have PFAS.
Who regulates PFAS in Wisconsin?
DNR regulates how much PFOA and PFOS can be released into the surface water (lakes, rivers, and streams) and how much PFOA and PFOS can be in water served by public water systems. DNR also oversees the clean up of contaminated sites.
On April 10, 2024, the U.S. Environmental Protection Agency (EPA) released final maximum contaminant levels (MCLs) for six PFAS. Wisconsin is taking steps to adopt new drinking water standards for the six PFAS. View the DNR's website for the status and proposed timeline of the rulemaking process.
Related topics
- Our groundwater standards page has information on how Wisconsin's groundwater standards are set, DHS' role in the process, and a summary of the current and recommended standards including PFAS.
- The Wisconsin Groundwater Coordinating Council's Annual Report to the Legislature summarizes the actions that state agencies to address groundwater issues including PFAS.
- DNR's PFAS page has information on fish consumption advisories, current PFAS sites and investigations, and PFAS-related public meetings.
- DNR's PFAS Interactive Data Viewer shows locations throughout Wisconsin that have been impacted by PFAS.
- The Agency for Toxic Substances and Disease Registry's (ATSDR's) PFAS health effects page has additional information on what PFAS are, how people can be exposed, and how PFAS can affect health.
- ATSDR's PFAS ToxFAQs page also has information on exposure routes and health effects.
- EPA's Per- and Polyfluoroalkyl Substances (PFAS) page has information on the current scientific understanding of PFAS, actions that EPA is to address PFAS, and links to resources, data, and tools.