Chemicals commonly used in everyday products – from pizza boxes to nonstick pans – are found to have characteristics similar to known carcinogenic chemicals.

Since the 1950s, thousands of different per- and polyfluoroalkyl substances (PFAS) have been used for a variety of reasons, but it was their use in firefighting foams that have resulted in extensive contamination around the world. Because PFAS build up in the human body over time and never break down in the environment, human exposure is extensive and detectable in nearly every person, starting with exposure in the womb. Exposure has been linked to a variety of ailments, including hormonal dysregulation, weakened immune system, reproductive and developmental harms, as well as reduced effectiveness of vaccines.

Now, scientists at the Environmental Working Group (EWG) and Indiana University report that nearly every PFAS analyzed presents the same characteristics as other cancer-causing chemicals. Used the Key Characteristics of Carcinogens, a framework established to evaluate and identify carcinogenic products, researchers conducted a review of 26 PFAS to determine whether a chemical causes damage to DNA, induces oxidative stress, or causes chronic inflammation, among other things.

Every PFAS analyzed displayed at least one characteristic of other carcinogenic chemicals, despite differences in reporting and approaches for estimating levels across the studies reviewed.

“We found strong evidence that multiple PFAS induce oxidative stress, are immunosuppressive, and modulate receptor-mediated effects. We also found suggestive evidence indicating that some PFAS can induce epigenetic alterations and influence cell proliferation,” write the authors in the journal International Journal of Environmental Research and Public Health.

The findings build on previous work that further illuminated the potential dangers of these “forever chemicals.” A previous analysis of more than 70,000 people who lived or worked where drinking water was contaminated with PFOA chemicals was found to have an increased risk of non-Hodgkin lymphoma as well as kidney, testicular, prostate, and ovarian cancers. PFOA chemicals were used by DuPont to make Teflon. Earlier this year, the EWG found that PFAS chemicals were present in drinking water of dozens of US cities and are widespread in rainwater, making it likely that the chemicals are found in a majority of major US water supplies.

"Our research has shown that PFAS impact biological functions linked to an increased risk of cancer," said Alexis Temkin, PhD, EWG toxicologist and the primary author of the new study, in a statement. "This is worrisome, given that all Americans are exposed to PFAS mixtures on a daily basis, from contamination in water, food and everyday products."

The researchers conclude that officials should focus on preventing cancer by preventing human exposure to potential carcinogens, perhaps beginning with PFAS.