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.

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.

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.

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.

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

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

BPA-free plastics often contain other harmful 'forever chemicals.'

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.

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.

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.

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.

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.

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.

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.

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).

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.

The FDA claims microplastics have not yet been shown to pose a health risk

Although microplastics and nanoplastics are found in many foods and environments, their presence does not violate regulations. Additionally, as of 2025, the administration believes evidence does not confirm that detected levels harm humans.

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.

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."

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.

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.

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.

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

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.

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.

1 in 6 Americans get food poisoning each year

The US federal government estimates there are about 48 million cases of foodborne illness in the country annually, resulting in as many as 3,000 deaths and 128,000 hospitalizations. Food poisoning puts those with weakened immune systems, the elderly, pregnant people, and young children at particularly high risk. This chart of common disease-causing pathogens highlights common threats and details about them, including likely food sources.

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.

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.

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.

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.

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.

Look up where your generic prescription drugs are made

This project from investigative journalism outlet ProPublica compiled source data for most generic prescription drugs in the US. Roughly 90% of drugs on the market are generic, and in rare cases investigators have noted issues with compliance or safety at some plants. Using your drug's name and the company on the label, find out any issues with your drugs here.

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

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.

The Clean Water Act became the national standard for protecting American waters

Enacted in 1972, the Clean Water Act grants the Environmental Protection Agency the authority to regulate pollutant discharges, establish water quality standards, and oversee water pollution controls. Its scope has narrowed due to recent Supreme Court rulings.

No one is tracking the total number of animals used for research across US labs, though partial data without any rodents puts the 2024 count above 775,000 animals, including some 40,000 dogs and 100,000 primates.

27% of US menopausal women used estrogen in 1999, but by 2020 that number was under 5%

The fallout of studies in the early 2000s linking hormone therapy for menopause and elevated cancer, stroke, and other health risks meant that even decades later—yet before the FDA removed its black box warning in 2025—use of HRT remained extremely uncommon. (Some users may experience a paywall.)

The plastics industry spent decades promoting recycling while privately doubting it would ever work

This FRONTLINE investigation reveals that plastic makers publicly championed recycling for years despite internal doubts about its viability, and that no more than 10% of the plastic ever produced has been recycled.

America doesn't have enough estradiol patches for menopause and perimenopause demand

Fueled in part by the lifting of the FDA's black box warning about HRT risks, sales of estradiol patches in the US have shot upward. More than 142 million units of the patches were sold in 2025 versus 46.5 million in 2020. Suppliers are failing to keep up with demand—11 patch products were in short supply in early 2026. (Some users may experience a paywall.)

Restaurants are where most of us contract food poisoning in the US

From 2014 to 2022, most reported foodborne illness cases occurred at restaurants. Between 2020 and 2022—when COVID-19 also likely influenced restaurant eating habits and tracking—there were only 238 foodborne illness outbreaks linked to restaurants, down from 714 the prior two years. Still, restaurants were behind most reported outbreak cases. (Some readers may experience a paywall.)

FDA removed its cardiovascular risk warning on testosterone products in 2025

The change came a decade after the FDA added the label. Recent work, including a gold-standard randomized trial, found that men receiving the products had similar cardiovascular risk levels as men taking placebo products. Testosterone, however, may hold other health risks, including infertility.

Countries tried to curb plastic waste, but the US keeps shipping more

Data show that American exporters continue to ship plastic waste overseas, often to poorer countries, even though most of the world has agreed to not accept it.

Peanut allergies dropped by 43% after doctors reversed avoidance guidance, but questions remain

The study’s data appear to confirm the policy shift. Still, since the study did not include an examination of infant diet, researchers can’t definitively say that the guideline shift led to dietary changes and thus directly caused the decline.

More than 130 nations have enacted bans or restrictions on plastic items

Several US states have enacted similar restrictions on plastic bags, straws, food containers, and other single-use plastics, while others have prohibited plastic bans. Despite this, California’s plastic bag ban cut usage by more than 70%, showing the potential of these policies.

How Big Oil misled the public into believing plastic would be recycled

An NPR and PBS Frontline investigation reveals how the oil and gas industry used the promise of recycling to sell more plastic, even when they knew it would never work on a large scale.

Roughly 40% of basic US research is federally funded, including much of the foundational research that underpins modern vaccines.

How a black market for banned refrigerants still threatens ozone recovery and climate progress

Despite the Montreal Protocol's success, illegal trade in chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons persists. Driven by high profits and weak enforcement, smugglers supply banned refrigerants, causing significant ozone depletion and greenhouse gas emissions equivalent to billions of tons of carbon dioxide.

The USDA does not claim that organic food is healthier than the alternatives

Although many believe organic food to be healthier, the USDA's organic label refers to methods used to grow the food rather than any potential health benefits. Still, a 2016 Pew Research Center study found that 76% of people purchased organic food for its health value.

More than 90% of America’s food allergies are triggered by 9 foods

Milk, egg, peanut, tree nuts, soy, wheat, fish, shellfish and most recently, sesame, are recognized as the most common food allergies in the US. Together, they are responsible for at least 90% of the serious food allergy responses in the country.

Psychedelics are being fast-tracked for research after a 2026 executive order

Many such compounds (including LSD, psilocybin, and more) are classified as Schedule I drugs—illegal to possess and federally regarded as having no medical use. Researchers say such restrictions have created significant hurdles for formal clinical trials. With this executive order, the FDA will enable work particularly focused on depression, PTSD, and alcohol use disorder.