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.

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.)

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

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 results above national limits.

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.

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.

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.

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

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 sea spray.

The Office of Chemical Safety and Pollution Prevention regulates toxic substances

This office evaluates and manages risks from industrial chemicals and pesticides. It reviews new chemicals before they enter the market, restricts hazardous substances, and promotes safer alternatives to protect human health and the environment.

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.

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.

Supplements often have issues with impurities, toxins, and inaccurate labels

Consumer Reports' tests of more than 20 supplement powders and shakes in 2025 found that more than two-thirds of them contain unsafe levels of lead. Some contained 10 times the amount of lead that's considered acceptable to ingest in a day. The levels they found, in some cases, were even higher than when they tested the products 15 years earlier.

The five most common chemicals found in modern food

Most modern processed foods rely on a number of preservatives to stay fresh from production to our plates. The most common include citric acid (preservative and flavor), sodium benzoate (preservative), xanthan gum (thickening and stabilizing), carrageenan (thickening), and red dyes 3 and 4 (for color).

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

As of 2025, the FDA states that microplastics have not yet been shown to pose a risk to human health, though it acknowledges that evidence suggests microplastics and nanoplastics have entered the food supply.

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

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.

Listen to how the 1902 'poison squad' experiments changed food safety in America

As part of government research, a group of young men were paid to eat standard American food—replete with food additives like borax and formaldehyde—which revealed the dangers of unregulated food. The work was led by the first FDA commissioner, Harvey Wiley, who helped end the "century of the great stomachache."

Pollution from lead battery recycling has led to widespread contamination

Many small-scale operations worldwide remain unregulated, bypassing environmental regulations and causing increasing health threats, primarily to children. A 2020 report by UNICEF found that one-third of the world's children are being poisoned by lead from recycled batteries, among other sources.

Why it's so hard to end the use of toxic lead

Lead was one of the earliest metals mined on Earth, desired for its soft malleability and used in cosmetics, pipework, gasoline, and more. But even though researchers demonstrated its toxicity in the 20th century, much of the world still uses it.

The amount of plastic chemicals in 300 everyday Bay Area foods

Food production is more complicated than it appears, and manufacturing, packaging, and shipping processes can add significant substances to your food. This massive project compiled data on 300 samples of foods delivered to the San Francisco area, testing for the presence of 18 different kind of plastic. Learn how to read the data here with its helpful guides and then explore the table yourself.

How a government chemist founded the FDA—by poisoning people

The Poison Squad tells the story of government chemist Dr. Harvey Wiley who, determined to banish these dangerous substances from dinner tables, took on the powerful food manufacturers and their allies.

Revelations that apples were sprayed with the chemical Alar led to its ban in the 1980s

Almost three decades after Rachel Carson’s “Silent Spring,” a “60 Minutes” segment on the use of Alar, a chemical sprayed on apples, drew national attention and inspired supermarkets and schools to remove apples from their shelves and cafeterias. That same year, the Environmental Protection Agency took action against the use of the chemical in food.

One in six Americans contracts food poisoning each year.

The US FDA recently tried to regulate the expanded prenatal genetic tests

The agency proposed a new rule in 2023 to make it explicit that these types of tests are devices under existing law and clarify that that the agency could move to regulate them. They finalized a regulatory change in 2024 that added the words "including when the manufacturer of these products is a laboratory" to an existing law, but a federal district court vacated that edit in March 2025—returning the law to as it was before.

The Love Canal disaster exposed the dangers of buried toxic waste

In the late 1970s, residents of Niagara Falls, New York, discovered their neighborhood was built atop 20,000 tons of chemical waste. Leaking toxins caused illness and birth defects, sparking nationwide outrage and leading to the creation of the EPA's Superfund cleanup program in 1980.

The EPA budget was 0.2% of total federal spending in 2024

The EPA spent $13.7B in 2024, making it 23rd among federal agencies in total expenditures. Of that money, more than half was distributed to state environmental agencies for sustainability and environmental protection programs.

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.

The Safe Drinking Water Act protects tap water for Americans

Passed in 1974, the Safe Drinking Water Act requires the EPA to set and enforce national standards for public water systems. It regulates contaminants, funds infrastructure improvements, and ensures that communities nationwide have access to safe and clean drinking water.

Explore a database of generic drugs to trace their origins and identify any safety concerns.

Microplastics are infiltrating the human body with unclear but concerning effects

Scientists have linked microplastics to immune system damage, hormone disruption, inflammatory diseases, and even cancer—yet most of their health impacts remain unknown due to limited research. Studies suggest we ingest about a credit card's worth of plastic weekly.

Ultraprocessed foods include preservatives, dyes, sweeteners, and more

Processed foods are those that have been altered from their original state, which includes numerous processes that we consider natural, such as cooking or salting. Ultraprocessed foods contain at least one item that wouldn’t be found in a kitchen, like hydrogenated oils or high-fructose corn syrup. It’s estimated that nearly 75% of all foods consumed in the US are ultraprocessed, though that doesn’t mean that all of them are unhealthy. In fact, some, such as prepackaged whole wheat bread and soy milk, are recognized for their health benefits.

Dietary supplements are regulated like foods

This hour-long 2016 documentary from Frontline, the Canadian Broadcasting Corporation, and The New York Times examined the safety of dietary supplements. It noted that this then-$30B industry (it's at least doubled since then) suffers from irregularities and impurities. It warned that many Americans are unaware of the lack of regulatory oversight over these products.

Research shows that over 1,000 metric tons of microplastics fall on national parks every year—equivalent to 120 million bottles of water.

The US FDA issued a 2025 warning about BPC-157 and other popular peptides that are marketed for various regenerative properties.

Scientists still don't know why DEET is such an effective bug repellent

This chemical, used to keep ticks, fleas, mosquitoes, and other nuisance bugs away, is used by an estimated one-third of the US population and has been available to consumers since 1957. Researchers theorize that multiple mechanisms may be at work to deter bugs, including perhaps masking or confusing bugs' olfactory receptors.

Is Agent Orange still causing birth defects?

Though the dangerous nature of the chemical is clear, its impact across generations is less so. How far down the bloodline does Agent Orange travel, and what does it leave in its wake, if anything? This Scientific American article examines why there’s debate about Agent Orange’s legacy.

Rachel Carson's 'Silent Spring' exposed the harmful effects of pesticides on food

The 1962 book warned against the use of DDT, a pesticide often sprayed over fields of crops, cautioning that it could be harmful if ingested in excessive amounts by humans. Some credit Carson’s book with inspiring the modern environmental movement and with encouraging the US to establish the Environmental Protection Agency in 1970 and ban the domestic sale of DDT in 1972. (Some readers may experience a paywall.)

As of 2026, the majority of US states have unsafe radon exposure levels

Alaska, South Dakota, Pennsylvania, Ohio, and Washington top the list of states with exposure levels above 4 picocuries per liter for this naturally occurring radioactive gas. While these state-level averages vary from one county, municipality, and home to another, the EPA encourages those in the highest-risk states to test their homes.

The WHO labeled aspartame as 'possibly carcinogenic' but US regulators consider it safe

The International Agency for Research on Cancer, an arm of the World Health Organization, labeled aspartame—the artificial sweetener in Diet Coke—as one of several hundred possible cancer-causing substances in 2023. The determination was based on animal and human studies and "limited" evidence linking it to liver cancer. The WHO and US Food and Drug Administration both say the substance is safe at moderate levels. The FDA says a person weighing about 132 pounds would need to have 75 packets daily to reach an unsafe level.

Climate change skepticism and business interests politicized environmental protection

The EPA was created under a Republican administration with bipartisan support in response to overwhelming public demand during a time of visible pollution and environmental crises. Beginning with President Reagan, the agency was recast as burdensome, and environmental regulations have been gradually rolled back.

Food poisoning investigations have led to more than 1 billion pounds of food recalls

PulseNet is the US government’s real-time foodborne illness tracking system for leading causes of food poisoning. There, a network of labs and scientists share DNA sequences for pathogens collected from contaminated food and also from sickened individuals, looking for patterns in the pathogens’ genome sequences that will help them hopefully finger a certain food, warehouse, producer, or restaurant.

Why a Montreal Protocol amendment cut back on the replacements for CFCs

Hydrofluorocarbons were introduced in the 1990s as ozone-safe substitutes for chlorofluorocarbons and hydrochlorofluorocarbons. However, scientists later found that they trap thousands of times more thermal energy in the atmosphere than carbon dioxide does, prompting a 2016 amendment to the Protocol to phase them out.

Food companies usually issue recalls voluntarily and you can be automatically notified about them

Protecting yourself from food poisoning means staying on top of food recall announcements. Notices about these from the US government, which you can automatically receive after signing up at this link, note what products have been recalled by food companies. Companies alert the US Food and Drug Administration or the US Department of Agriculture when they issue recalls so the public can stay informed.

Rachel Carson didn't argue for wholly organic farming

Her 1962 book, “Silent Spring,” inspired many people to consider the chemicals used to grow their food, but Carson didn’t think that manufactured fertilizers needed to be banned from farming, writing that “The ultimate answer is to use less toxic chemicals so that the public hazard from their misuse is greatly reduced.” When she testified to Congress in 1963, she said, “I think chemicals do have a place.”

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.