Study finds multiple PFAS, the man-made ‘forever chemicals’, in 98.5% of people tested in US study

Man-made 'forever chemicals' have been detected in 98.8% of blood tests, in a new study which examined more than 10,500 samples.

The findings are the latest indication to suggest that nearly every single person in the US is living with PFAS (per- and polyfluoroalkyl substances) – and usually multiple – in their system.

The results, published in the peer-reviewed Journal of Occupational and Environmental Hygiene, show that most individuals (98.5%) were, in fact, carrying multiple types of these environmentally persistent chemicals in their blood.

The paper demonstrates one of the largest-ever sample sizes determining PFAS levels in blood.

PFAS are a group of approximately 10,000, so-called, forever chemicals – as they do not degrade easily and build-up in the environment and human body. Used for decades, they can be found in thousands of day-to-day items ranging from clothes and cooking utensils to electronics and medical equipment. They live in our food, water and homes.

The dangers of all PFAS are not fully known; however, previous studies have linked some of them to serious complications, including cancer, infertility, high cholesterol, and weakened immunity.

One of the PFAS most commonly detected in this new study (in 97.9% of samples) was perfluorohexane sulfonic acid (linear PFOA), which is already recognised as being linked to adverse health conditions – including potential impacts on the immune system, liver, and thyroid – prompting action, internationally, for its restriction.

Commenting on the results, lead author, Dr Laura Labay, Principal Toxicologist at NMS Labs – the leading independent provider of professional laboratory testing services in the USA – says it is hoped their new dataset can offer future interventions.

“This large dataset provides a real-world snapshot of how multiple PFAS commonly occur together in people. By identifying these shared exposure patterns, the study offers a greater understanding of what widespread, combined PFAS exposure may mean for human health. We hope these findings will help inform future risk-assessment efforts, guide research on harmful PFAS mixtures, and ultimately support clearer clinical and public-health guidance.”

The data in this report were derived from 10,566 serum and plasma samples, of which a PFAS co-positivity assessment was performed by the NMS Labs team. Most samples (10,478) were tested for 13 different PFAS, whilst 88 samples were tested for 18 PFAS. 58 unique chemical combinations were found when testing for 13 PFAS and 16 different combinations were found when testing for 18 PFAS.

Overall, they found 98.8% of samples contained at least one PFAS. Only 19 samples (0.18%) contained a single PFAS, at the lower limit of the reporting threshold (0.1 ng/mL).

Across both testing panels, the most common combination included five PFAS, including historically used PFOS and PFOA as well as their replacement chemicals, frequently found in consumer products such as nonstick cookware, stain-resistant fabrics, and firefighting foam. This combination was detected in 2,754 samples, or 26.1% of those tested.

“These findings reinforce that PFAS exposure rarely occurs as isolated compounds,” Dr Labay adds.

“Instead, individuals typically carry body burdens comprising five or more PFAS with differing bioaccumulation properties and half-lives. The high prevalence and consistency of specific PFAS combinations highlight the importance of mixture-based interpretation in biomonitoring, particularly given PFAS’ potential to affect multiple biological systems in the body.”

The authors detail that limitations of the paper include that not all PFAS potentially present in the samples may have been considered, which may have led to underestimation.