Although PFAS, or forever chemicals, are intentionally designed to be extremely stable and long-lasting because of their strong carbon-fluorine bonds, these bonds can be broken by heat, plasma, and supercritical water.

Used since the 1940s, 'forever chemicals' include thousands of different types of substances routinely integrated into industry and consumer products, yet research suggests they can accumulate in the body over time.

Forever chemicals are so common that experts concluded in 2022 that it's uncertain whether limiting consumer exposure would truly reduce one's exposure to these substances, and noted it would still take years for the body to clear them.

Watch 'Last Week Tonight' explore the risks of 'forever chemicals,' a group of human-made chemicals used in everyday products to make them resistant to water, stains, grease, and heat. (Warning: language.)

Per- and polyfluoroalkyl substances (PFAS) are a group of human-made chemicals used in a wide range of products due to their unique properties. However, because they can persist in the body and environment for thousands of years, they've earned the moniker "forever chemicals"—and have been linked with numerous health risks.

Teflon was an accidental discovery by a DuPont scientist in the 1930s resulting from efforts to create a safe refrigerant.

Why bacterial bioremediation may help counter the negative effects of past chemical solutions

Molecules such as DDT, a synthetic insecticide, and PFAS—"forever" chemicals used to make products resistant to heat, water, and grease—have historically been used across various industries but are now known to be harmful. Microbes that can convert some of these substances into nontoxic products, such as water and carbon dioxide, have already been identified, with ongoing research to find others.

See this interactive global map that highlights which forever chemicals have been detected in specific wildlife species, providing data on hundreds of species exposed to these hard-to-breakdown substances.

Forever chemicals accumulate up the food web, with recent research indicating that apex predators have higher concentrations because they're eating prey that also have accumulated the substances.

Explore this interactive EPA map, which shows 'forever chemical' testing results for public water systems—with brown spots indicating testing above national limits.

A remote Scottish island is awash in forever chemicals even though there are no obvious industrial sources nearby, and scientists suspect the toxic substances are accumulating via seaspray.

Most of the 86,000 consumer chemicals registered with the US EPA have never received rigorous toxicity testing, though not all those are still in current use.

Fluorinated molecules are the most impactful, longest-lasting greenhouse gases

Developed as replacements for ozone-depleting substances in refrigeration and air conditioning systems, these compounds are released through leaks in and ongoing use of these appliances, as well as from various industrial processes. They can remain in the atmosphere for thousands of years and have warming potentials that are a thousand to tens of thousands of times greater than those of carbon dioxide.

Japanese scientists have developed an eco-friendly plastic that naturally dissolves in hours, leaving behind molecules containing phosphorus and nitrogen, which fertilize soil.

Microplastics are entering human food chains through carrots, wheat, and other foodstuffs grown in farmlands fertilized by sewage sludge.

Listen to a reporter discuss his story spotlighting a decades-long corporate cover-up about forever chemicals, substances which can persist in the environment for hundreds of years—though not forever.

Microplastics from sewage sludge persist in farmland soil for decades

A 25-year study in Scotland found that sewage sludge used as fertilizer introduces various microplastics into soil, where they remain and degrade into smaller particles that worsen soil quality. Dyes found in microplastics may also be leaching into the environment, causing additional toxic effects.

How sunlight helps chlorofluorocarbons destroy the ozone molecules that block solar radiation

CFCs, which are used in old refrigerants, air conditioners, and aerosol sprays, do not react with atmospheric molecules. Once they reach the stratosphere, ultraviolet radiation breaks chlorine atoms off of them, which can each break apart more than 100,000 ozone molecules, thinning Earth's protective layer against ultraviolet radiation.

Why the bioremediation of plastic and other synthetic materials is challenging

Ideonella sakaiensis, a bacterium found in recycling plant sludge in 2016, was the first organism seen to possess enzymes that could break down PET, a type of plastic. Researchers continue to search for microbes to expand bioremediation efforts to other types of plastic, but weakening the chemical bonds in many of these materials requires temperatures lethal to most microbes.

Fracking provides access to fossil fuel reserves locked in underground rock

Using a pressurized fluid mixture that is over 90% water, cracks are created in shale about 2 miles deep to release trapped oil and natural gas. The process uses an average of 3 to 6 million gallons of water per well, which can strain local water supplies.

How chemical recycling could create 'infinite' plastic

The way we normally recycle plastics is a downward spiral of waste and degraded materials, but there is another option—turning plastic back into the oil it was made from.

The adaptations of metallophiles and how they can be harnessed for bioremediation

These extremophiles have adapted to biomes with very high concentrations of metals and toxic chemicals by developing mechanisms to isolate these substances within cellular compartments and break them down into less harmful forms with specialized proteins. They have the potential to support the decontamination of metal-rich wastewater and soil, as well as the extraction of rare-earth metals.

Some faucets in regions near fracking wells run flammable water

A 2011 study found methane contamination as much as 3,000 feet away from wells, although there was no evidence of fracking chemicals in tested wells. Water with low methane concentrations is not harmful to drink, but it becomes flammable when mixed with air.

Many chemicals used in fracking fluid have been classified as toxic

Although the fluid has been known to leach into drinking water supplies, raising health concerns, fracking is exempt from federal clean water regulations due to a loophole in the Energy Policy Act of 2005 championed by former US Vice President Dick Cheney.

Stainless steel and cast-iron pans should be used over older nonstick cookware

Although modern nonstick pans avoid forever chemicals like PFOA, they were previously used in the manufacturing of Teflon coatings and have been linked with certain types of cancer, infertility, and other adverse health outcomes. Vintage plastic utensils should also be avoided due to the leeching of contaminants in early formulations of plastic.

BPA-free plastics may still pose health risks because they often contain other structurally similar chemicals.

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

Find fracking wells where you live and what chemicals operators are using

Fracturing fluid recipes are largely proprietary, but FracFocus has maintained a database of chemical disclosures since 2011. Today, the Department of Energy-affiliated nonprofit has more than 240,000 disclosures, along with a searchable database of fracking wells by state, county, and city.

View the industrial applications of extremozymes, from food safety to antibiotic production

Extremophiles possess unique enzymes and organic molecules that have enabled them to adapt to and thrive in otherwise lethal environments. Because these conditions resemble those found in various areas of manufacturing and production plants, these organisms and their macromolecules can optimize industrial processes where conventional catalysts would lose their ability to speed up reactions.

Why extremophiles may play an important role in terraforming Mars

Possessing unique biochemicals that can detoxify extreme environments and resilience against the Martian surface that is lethal to humans, scientists are exploring whether colonies of these organisms can transform small areas of the Red Planet into future habitats for humans. Extremophiles may also be best equipped to serve as microscopic factories for the fabrication of essential polymers.

An overview of extremophiles and the biochemical adaptations employed by various types

These organisms thrive in environments that would normally be inhospitable to most living things by using molecules that help counter deadly environmental factors. These include antifreeze-like proteins that prevent psychrophiles from freezing and rupturing in polar regions, and osmoprotectants that prevent some extremophiles from losing water to salty environments.

Washing clothes is a significant source of global microfiber pollution

Synthetic fabrics shed millions of plastic microfibers during washing, which pass through wastewater treatment and end up in oceans, soil, and food chains. A single wash load can release several million microfibers, but washing with cold water can reduce this.

Breaking down the different types of drinking water, from alkaline to sparkling

While tap water is regulated by the EPA, environmental and infrastructural factors can introduce contaminants, which filtering can help to remove. Distilled water has had all of its mineral contaminants removed and may be used in laboratory settings, but mineral water has them added in for taste or to promote health.

Why water is the universal solvent, despite not being good at dissolving many substances

Because oxygen attracts electrons much more strongly than hydrogen does in H₂O, the molecule is polar, with a negative charge at the oxygen atom and positive charges at the hydrogen atoms. These charged regions can attract and pull apart charged portions of other polar molecules, such as washable inks, but are unable to dissolve nonpolar materials, such as glass and asphalt.

Despite being derived from crude oil, which itself comes from organic material, synthetic plastic isn't biodegradable because it hasn't existed long enough for microbes to have developed mechanisms to break it down.

Most biodegradable plastics don’t break down in everyday conditions

Despite their eco-friendly name, biodegradable plastics often require industrial composting, which most areas lack, to decompose the uncommon compounds found in them. This means they may linger in landfills or contaminate conventional plastics in recycling bins.

How the US Department of Energy facilitated bioremediation with emulsified soybean oil

At sites where soil and groundwater were identified as contaminated with volatile organic compounds, scientists and engineers at the Office of Legacy Management used microbes to safely clean them up without more invasive methods, such as pump-and-treat. Treatment zones created at one location by injecting oil to help microbes spread quickly.

Watch students comically portray how plants can detoxify the environment

Through a series of processes that collectively make up phytoremediation, plants can take up pollutants from soil and water through their roots, then break them down, release them as less harmful gases, or store them within their cells. Any plants that sequester heavy metals or other toxins must be removed and managed after the environment is decontaminated.

Explore how close you live to some of the most contaminated places in the US

Known as Superfund sites, these toxic locations undergo long-term cleanup to remove hazardous waste, protect health, and restore land for safe reuse. As of 2025, the EPA lists around 1,300 active Superfund sites on its National Priorities List, with more than 450 cleaned and removed since 1980.

Fireworks contribute to air, water, and soil contamination and disrupt wildlife

Fireworks displays have far-reaching environmental consequences, including acid rain from displays during storms and microplastic pollution in water supplies. Wildlife has also been seen abandoning sites during fireworks and never returning.

Microplastics have been found everywhere there is liquid or vapor water, from the oceans and tropical waters to polar ice and the air we breathe, posing growing risks to wildlife and ecosystems.