Artificial “forever chemicals” have been detected in 98.8% of blood samples analysed in a major new US study involving more than 10,500 tests, adding to growing evidence that exposure to PFAS is now almost universal across the American population. Researchers found that most individuals were carrying not just one, but multiple forms of the chemicals in their bloodstream.
The findings, published in the peer-reviewed journal the Journal of Occupational and Environmental Hygiene, revealed that 98.5% of participants had several different PFAS compounds present in their blood. The research represents one of the largest investigations ever conducted into PFAS concentrations in human blood samples.
PFAS, or per- and polyfluoroalkyl substances, are a large group of around 10,000 synthetic chemicals commonly referred to as “forever chemicals” because they break down extremely slowly and accumulate in both the environment and the human body. For decades, they have been widely used in consumer and industrial products, including non-stick cookware, stain-resistant fabrics, electronics, food packaging, firefighting foams, and medical equipment. As a result, they are now commonly found in water, food, household dust, and everyday environments.
Although the full health effects of many PFAS remain unclear, previous research has linked certain compounds to serious health risks, including cancer, infertility, elevated cholesterol levels, thyroid disruption, liver damage, weakened immune function, and developmental problems. One of the chemicals most frequently identified in the new study, perfluorohexane sulfonic acid, was detected in 97.9% of samples and has already prompted international efforts aimed at restricting its use because of concerns about its potential health impacts.
Lead author Laura Labay said the findings provide an important real-world picture of how PFAS exposure typically occurs. According to Dr Labay, people are rarely exposed to a single PFAS compound in isolation, but instead carry complex mixtures of several chemicals with differing persistence and biological effects. She said the dataset could help improve future risk assessments, guide research into the combined effects of PFAS mixtures, and support clearer public health and clinical guidance.
The research analysed 10,566 serum and plasma samples collected and tested by NMS Labs, a major independent laboratory testing provider in the United States. Most samples were screened for 13 PFAS compounds, while a smaller subset was tested for 18. Researchers identified dozens of distinct chemical combinations, with the most common pattern involving five separate PFAS compounds, including older chemicals such as PFOS and PFOA alongside newer replacement compounds. This five-chemical combination appeared in more than one-quarter of all samples tested. The authors noted that the study may still underestimate total exposure levels because not every PFAS compound potentially present in the samples was examined.
More information: Laura Labay et al, PFAS co-positivities identified in more than 10,000 serum/plasma samples, Journal of Occupational and Environmental Hygiene. DOI: 10.1080/15459624.2025.2601605
Journal information: Journal of Occupational and Environmental Hygiene Provided by Taylor & Francis Group
