Rain is falling somewhere above the Tibetan Plateau, where the closest factory is hundreds of miles away and the air is thin. And in that rain, in one of the world’s most isolated locations, as far away from a nonstick skillet or an airport fire drill as it gets, Stockholm University researchers discovered PFAS. The interior of fast-food containers is coated with the same artificial chemicals. the same substances found in military bases’ firefighting foam. Rainwater floating over a mountain range that most people will never see is a measurable manifestation of this. “You can’t live anywhere on the planet and be sure that the environment is safe,” stated Professor Ian Cousins, the study’s lead author from 2022.
You should take your time reading that sentence. Rainwater samples from locations all over the world were compared to the current US drinking water advisory levels in order to arrive at a literal scientific conclusion, not hyperbole or the kind of dramatic overstatement that occasionally surrounds environmental reporting. It was not a close comparison. It was discovered that PFAS concentrations in rainwater in isolated places, such as Tibet, Antarctica, and the open ocean, “greatly exceed” those safety thresholds. This presents a clear and unsettling question: what precisely are safety regulations protecting if the rain itself is contaminated?
| Category | Details |
|---|---|
| What are PFAS | Per- and polyfluoroalkyl substances — over 15,000 synthetic compounds used commercially since the 1940s–50s; characterized by carbon-fluorine bonds, one of the strongest in chemistry; found in non-stick cookware, food packaging, firefighting foam, cosmetics, clothing, and more |
| Why “forever chemicals” | PFAS do not degrade easily in the environment or the human body; some variants persist for hundreds to thousands of years; accumulate in water, soil, air, wildlife, and human blood and breast milk |
| Rainwater finding (2022) | Stockholm University study found PFAS levels in rainwater across most locations on Earth — including remote sites in Tibet and Antarctica — “greatly exceed” US drinking water safety advisory levels; researchers concluded a planetary boundary has been crossed |
| Miami rainwater study (2024) | Florida International University found PFAS in Miami’s rainwater, confirming these chemicals are circulating globally through the water cycle — not confined to industrial zones or known contamination sites |
| Known health risks | Decreased fertility; increased blood pressure in pregnant women; developmental delays and low birth weight in children; increased risk of prostate, kidney, and testicular cancers; immune system suppression including reduced vaccine response; hormonal disruption; increased cholesterol and obesity risk |
| Corporate suppression | A 2023 UC San Francisco study revealed that companies including 3M and DuPont had internal knowledge of PFAS health risks since the 1970s and suppressed the information for decades; both companies have since faced major litigation and settlements |
| US regulatory status | EPA designated PFOA and PFOS as hazardous substances under Superfund in 2024; set maximum contaminant levels for six PFAS in drinking water; however, in May 2025 the EPA announced plans to repeal health standards for four of those six PFAS — a significant reversal |
| European regulation | PFOA banned in Europe since July 2020; PFOS restricted since 2009; European Packaging and Packaging Waste Regulation sets 50 ppm PFAS limit for food packaging from August 2026; EFSA tolerable weekly intake set at 4.4 ng/kg body weight for a combination of four key PFAS compounds |
| Netherlands case study | When the Netherlands set new PFAS limits on soil and dredging material in 2018, 70% of construction projects were halted; government subsequently relaxed the guidelines — illustrating the economic-regulatory conflict at the heart of PFAS policy |
| Children’s vulnerability | Children face higher PFAS exposure relative to body weight due to higher food, water, and air intake per pound; crawling on floors increases dust ingestion; infants can be exposed through breast milk and formula made with contaminated water |
| Removal from drinking water | Technical removal of PFAS from drinking water at treatment plants is possible but expensive; getting below current US advisory levels is described by researchers as “extremely challenging” — and economically impractical at scale |
| Expert quote | Prof. Ian Cousins, Stockholm University (lead author of 2022 rainwater study): “You can’t live anywhere on the planet and be sure that the environment is safe” — adding that applying current safety guidelines universally would make construction and industry economically impossible |
Since the late 1940s, PFAS, or per- and polyfluoroalkyl substances, have been produced and used commercially. They initially appeared in Teflon and later spread to food packaging, firefighting foam, water-repellent clothing, cosmetics, dental floss, paint, and carpet treatment. More than 15,000 variations are currently recognized. Their chemistry is based on one of the strongest carbon-fluorine bonds found in nature, which is why they are so useful for commerce and why they never disappear. PFAS build up in the human body, the environment, the fat cells of Arctic animals, and the breast milk of mothers in the US and the Netherlands. The body lacks a dependable system to degrade them. The soil doesn’t either. The rain doesn’t either.
The length of time that the major manufacturers were aware of the dangers before the general public was makes the PFAS story especially challenging to comprehend. According to a 2023 UC San Francisco study, companies like 3M and DuPont knew about the possible health risks of PFAS exposure as early as the 1970s, but they kept that information hidden for decades. Long before they were documented in peer-reviewed literature, the health risks that scientists are currently attempting to fully characterize—reduced fertility, developmental delays in children, increased risk of certain cancers, immune suppression, and hormonal disruption—were being raised internally at those companies. Since then, both businesses have been involved in significant litigation and have reached billion-dollar settlements.
In certain respects, the discrepancy between what science says and what policy demands is growing, and the regulatory response has been inconsistent. A major regulatory step was taken in 2024 when the US EPA classified PFOA and PFOS as hazardous substances under Superfund and established maximum contaminant levels for six PFAS compounds in drinking water. The EPA then declared in May 2025 that it would lower health standards for four of those six substances. Although the legal and practical ramifications of that reversal are still unknown, researchers who have spent years pushing regulatory thresholds in the exact opposite direction are concerned about the direction of travel. Although there is still disagreement over how to regulate the entire class of more than 15,000 compounds, the European Food Safety Authority has set tolerable intake levels, banned certain compounds, and strict food packaging limits that will take effect in 2026.
An interesting case study of what happens when environmental science and economic reality collide is the Netherlands. The nation imposed stringent new restrictions on PFAS concentrations in dredging material and soil in 2018. As a result, about 70% of building projects that involved excavated soil were abandoned. The government later loosened the regulations due to intense economic pressure. Professor Cousins, who has observed this dynamic in various regulatory contexts and nations, predicted that the US drinking water standards would likely follow the same pattern. He stated, “You wouldn’t be able to build anywhere,” illustrating the real-world implications of implementing the most recent safety regulations everywhere. “It’s just impossible, from an economic viewpoint.” That is a description of the predicament that the entire world has fallen into, not a declaration of acceptance.
Because they consume more food, drink more water, and breathe more air in relation to their body weight, children are absorbing PFAS at higher rates than adults. Babies may be exposed through formula made with tainted tap water or breast milk from mothers who have PFAS in their blood. The populations most at risk are typically those with the least access to fresh food, filtered water, and information about what they’re eating. These are documented exposure routes, not hypothetical ones. PFAS exposure has a socioeconomic component that permeates all serious analyses of the problem but doesn’t always make the news.
It is technically feasible to remove PFAS from drinking water. Additionally, it is costly, and the researchers acknowledge that it is very challenging to achieve concentrations below current advisory levels at scale. Scientists discovered that the contamination is no longer local, containable, or reversible in any near-term sense in that Tibetan rainwater, Miami’s rain, and Antarctic ice cores. Now, the question is not how to stop what has already occurred—that window has closed—but rather how quickly and honestly the laws governing daily life can adapt to a chemical reality that has been subtly changing since the 1940s.
