City Cast Madison logo

PFAS, Explained.

Posted on January 24, 2024   |   Updated on September 30, 2025
Hayley Sperling

Hayley Sperling

Wearing gloves and holding a clear plastic bottle, Madison, Wis., resident Brad Horn collects a water sample to test for PFAS in Madison, Wis., on Aug. 8, 2022.

Madison resident Brad Horn collects a water sample to test for PFAS in Madison, on Aug. 8, 2022. (Coburn Dukehart / Wisconsin Watch)

You've probably heard the term PFAS come up plenty of times in the news, but you might not know exactly what they are or where they come from. Let’s fix that.

PFAS, or per- and polyfluoroalkyl substances, are a class of more than 14,000 human-made chemicals that have been used in both consumer and industrial products since the 1940s. They’re used in making many everyday items like fabric stain protectors, food packaging, non-stick cookware, and waterproof clothing. PFAS are also used in firefighting foam, lubricants, and paint.

Most people will encounter PFAS in the food they eat and the air they breathe. It’s hard to know when you’ve been exposed to the chemicals because they are often odorless, colorless, and tasteless.

Tap water can be a main source of exposure for those who live near contaminated sites but bathing in PFAS-contaminated water is unlikely to significantly increase exposure, according to the U.S. Centers for Disease Control and Prevention. A 2015 CDC study found PFAS in the blood of 97% of Americans.

The Potential for Harm

PFAS can accumulate in the environment and our bodies. The compounds don’t easily break down, which is why they are often referred to as “forever chemicals.”

There is still much that has yet to be discovered about PFAS and research is ongoing. Because there are so many kinds of PFAS, researchers face an immense challenge in studying the chemicals and their effects.

But studies have shown that exposure to certain levels of PFAS may lead to increased risks of cancer, obesity, birth defects, and more adverse health effects. The EPA has recently proposed regulations for some common PFAS chemicals.

When it comes to mitigating the effects of PFAS, limiting exposure is the best course of action. This can be done through water filtration and testing, limiting fast food consumption, washing produce well before eating, and always rinsing yourself and pets off after spending time in lakes, streams, and rivers.

An airplane takes off near the site where Starkweather Creek exits Truax Field Air National Guard Base and flows through pipes that feed the water downstream toward Lake Monona in Madison.

In 2019, Starkweather Creek contained higher levels of hazardous PFAS than any other waters the state tested that year. (Isaac Wasserman / Wisconsin Watch)

PFAS in Madison

Unfortunately, Madison and Dane County are no strangers to PFAS.

Surface water and fish in Starkweather Creek, Lake Monona, and several downstream lakes and rivers contain PFAS. The chemicals have also been found in soil, municipal wells, and groundwater. The city is working to remove PFAS from our drinking water, but it’s not cheap and it’s not easy.

A major known source of PFAS contamination in Madison is firefighting foam used at the Dane County Regional Airport and Truax Field Air National Guard Base. Stormwater runoff has carried PFAS-laden water into our lakes and streams.

You can use this map from the Wisconsin Department of Natural Resources to show locations throughout Wisconsin that have been impacted by PFAS.

Share article

Hey Madison

Sign up for your free daily toolkit to get the most of the city you love.

Can't subscribe? Turn off your ad blocker and try again.

Urban Almanac

See All
Urban AlmanacJune 11, 2025

When Is It Safe to Swim in Madison’s Lakes?

Summer is here and it's time to take a swim! But there are a few things to keep in mind before diving into one of Madison's lakes.

Two people swimming in a lake during sunrise.
Urban AlmanacMay 28, 2025

How To Keep Madison’s Wild Baby Bunnies Safe

The Dane County Humane Society’s Wildlife Center is receiving a lot of calls about Eastern Cottontail rabbits as people are finding more...

Gray Eastern Cottontail bunnies in a nest.
Urban AlmanacMarch 31, 2025

How To Take Care of Indoor Plants This Spring

Are you wondering how to take care of your indoor plants this Spring? Or thinking of getting some new ones? We dive into plant ideas and...

Collection of monstera and other indoor plants under a warm lamp taken from above
Urban AlmanacOctober 9, 2024

How a New Tool Helps Reunite Pets With Their Owners

A new Madison Police Department microchip scanner will help pet owners reunite with their lost dogs and cats.

Two women hold a bulldog and an electronic device.
Urban AlmanacOctober 2, 2024

Take a Break From the Rake!

Fall is here! Soon, you’ll be serenaded by the sound of your neighbor’s leaf blower, and wonder if it’s time to get out your own, or a ra...

The feet of a woman in a blue coat kick leaves in the forest.
Urban AlmanacSeptember 25, 2024

Why the Cows Come Home To the World Dairy Expo

The cows come home to Madison next week as the World Dairy Expo returns to the Alliant Energy Center Oct. 1 to Oct. 4. You might have hea...

A group of cows line up in a stadium on a green floor.
Urban AlmanacSeptember 18, 2024

Hang Out At Madison’s New Lakefront Porch Park

A lot of people passed by the Madison Water Utility reservoir at 201 S. Hancock St. and just saw concrete. But others saw an opportunity...

Tables and chairs sit on a wooden outdoor platform.
Urban AlmanacSeptember 11, 2024

A Sheep Way To Help Solar Projects

It’s a farm friendship as unlikely and fruitful as Charlotte the spider and Wilbur the pig – sheep and solar panels. Solar array projects...

Sheep graze in a field next to solar panels.

The latest in Madison

Madison, ExplainedMay 18

How Smart Studios Put Madison on the Musical Map

Why did Nirvana, Smashing Pumpkins, Death Cab for Cutie and other bands want to record songs in Madison? As a new documentary explains, S...

A two-story red brick building on a street.
Food & DrinkMay 14

These Madison Butcher Shops Are a Cut Above

With summer coming up, you might want to stock up for the next cookout. Here are some of Madison's favorite butcher shops, from Meat Peop...

A man in glasses peers at a stack of hamburger patties.
Madison's BestMay 12

Wisconsin Authors Are an Open Book on New Podcast

On the new podcast "Writing Forward," Madison writer Jeff Oloizia interviews Wisconsin authors about their writing process, how to be suc...

A man in a blue shirt stands next to a shelf of books.
Food & DrinkMay 7

Supper Clubs in Madison You Have To Try

You can savor the Wisconsin supper club tradition without traveling far from Madison, hitting historic spots like Tornado Steak House, Ka...

A photo of a plate of food and a nighttime photo of the exterior of a restaurant.
Madison, ExplainedMay 4

Quiz: Are you a True Madisonian?

You may live in Madison, but are you a true Madisonian?

A downtown street scene with a capitol dome at the top of the street.
Madison's BestApril 30

Your Guide to May 2026 in Madison

From Brat Fest to Tulip Fest, from 'Newsies' to Charlie Berens, there's lots going on in Madison this spring.

A man in a gray shirt in front of a blue brick wall.
Madison's BestApril 29

The Madison Mystery Tour Is Coming To Take You Away

Over a half-century after they broke up, the Beatles still have a huge hold on popular culture. For over a decade, the Madison Mystery To...

A man in a bow tie plays an electric guitar behind a man playing a keyboard.
Madison's BestApril 27

Madison’s Circus Scene isn’t Clowning Around

While Circus World in Baraboo is what put Wisconsin's circus scene on the map, there's lots of acrobatics, clowning and more going on in...

A man and a woman in a circus ring juggling hoops.