PFAS chemicals found in nearly all US blood samples, study shows

More than 10,500 blood samples drawn from across the United States reveal that the vast majority of people carry multiple types of PFAS, the synthetic compounds known as "forever chemicals." Published in the Journal of Occupational and Environmental Health, the research found that roughly 98.5% of specimens contained more than one of these substances, marking one of the largest surveys of their accumulation in human blood to date.

PFAS — per- and polyfluoroalkyl substances — represent a family of about 10,000 chemicals used for decades in everyday products: non-stick cookware, stain-resistant fabrics, electronics, medical devices, and clothing. Their defining trait is extreme persistence in the environment and the body, where they build up through water, food, and household dust without breaking down.

While the full health effects of every PFAS compound remain unclear, earlier studies have linked some of them to serious conditions including cancer, infertility, elevated cholesterol, and weakened immune function.

Most common compound and chemical mixtures

The compound perfluorohexane sulfonic acid (PFOA) appeared in 97.9% of samples, making it the most widespread. PFOA has been the subject of extensive prior research tying it to potential liver, thyroid, and immune-system harm, prompting several countries to restrict its use.

Researchers analyzed serum and plasma samples, screening for dozens of individual PFAS compounds and their combinations. When testing for 13 compounds, they identified 58 distinct chemical mixtures; testing for 18 compounds yielded 16 additional mixtures.

Nearly 99% of samples contained at least one PFAS compound, while only 0.18% held a single compound at the lowest measurable level. The most common mixture comprised five compounds, including PFOS and PFOA alongside chemical substitutes used in consumer goods such as non-stick pans, stain-resistant fabrics, and firefighting foam. That specific combination turned up in more than 2,700 samples — roughly a quarter of all participants.

Study co-author Dr. Laura Lapay said the findings show that exposure to these chemicals does not occur in isolation but as a blend inside the body. She noted that this pattern of combined exposure may be more significant than studying each substance individually, given how the compounds interact with different bodily systems.

The researchers acknowledged a key limitation: the analysis may not have captured every PFAS compound actually present in the samples, meaning real-world exposure levels could be higher than those reported.