PFAS – the man-made ‘forever chemicals’ – found in 98.8 per cent of people tested

Study of more than 10,500 serum and plasma samples has found that almost all participants carried at least one per- and polyfluoroalkyl substance in their blood, with most found to have multiple ‘forever chemicals’ present

Man-made ‘forever chemicals’ have been detected in 98.8 per cent of blood samples analysed in a large study of more than 10,500 serum and plasma specimens.

The findings have added to evidence that exposure to per- and polyfluoroalkyl substances (PFAS) is widespread across the population in the USA. The analysis found that almost all individuals tested had multiple PFAS present in their blood.

PFAS comprise a large family of at least several thousand synthetic fluorinated chemicals, with more than 4,700 identified in the OECD global database and broader scientific inventories extending into much larger numbers. Many do not break down readily in the environment and can therefore accumulate in human tissue.

But for decades, PFAS have been used in industrial processes and consumer products, including clothing, non-stick cookware, electronics, medical equipment, stain-resistant fabrics and firefighting foams. As a result, they have entered food, water and domestic environments.

The health risks of all PFAS are not yet fully understood. However, previous studies have associated some compounds in the class with serious adverse outcomes, including cancer, infertility, high cholesterol and reduced immune function.

The paper has presented one of the largest sample sets used to assess PFAS levels in blood with analysis of data from 10,566 serum and plasma samples that underwent PFAS co-positivity assessment. Most samples – 10,478 in total – were tested for 13 PFAS, while 88 samples were tested for 18 PFAS. The analysis identified 58 unique chemical combinations in the 13-PFAS panel and 16 distinct combinations in the 18-PFAS panel.

Overall, 98.8 per cent of samples contained at least one PFAS. Only 19 samples, or 0.18%, contained a single PFAS at the lower limit of the reporting threshold which is 0.1 nanograms per millilitre.

Across both testing panels, the most common chemical combination included five PFAS. These included historically used compounds, such as perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), as well as replacement chemicals that have been found in consumer products such as non-stick cookware, stain-resistant fabrics and firefighting foam. This five-PFAS combination was detected in 2,754 samples, equivalent to 26.1 per cent of those tested.

One of the PFAS most commonly detected in the study – perfluorohexane sulfonic acid – was reported in 97.9 per cent of samples.

“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,” said Dr Laura Labay, lead author and principal toxicologist at NMS Labs, an independent provider of professional laboratory testing services of Horsham, Pennsylvania, USA.

Dr Labay said the findings underlined the need to consider PFAS as mixtures rather than as isolated chemicals, particularly in clinical and public-health interpretation.

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

The authors noted that the study had limitations. Not all PFAS that may have been present in the samples were included in the testing panels which means that the analysis may have underestimated the full extent of exposure.

For further reading please visit: 10.1080/15459624.2025.2601605