Toxic “Forever Chemicals” Contamination May Be More Widespread Than Previously Thought

New modeling from the PFAS Project Lab at Northeastern University suggests that per- and polyfluoroalkyl substances (PFAS) may be present at nearly 80,000 additional locations across the United States – on top of the approximately 2,200 sites already identified through direct testing.

The research, published in Environmental Science & Technology, may paint a more complete picture of PFAS contamination, helping legislators and environmental activists with a more accurate roadmap of where may need additional focus.

Known sites underrepresent true scale

PFAS, a class of synthetic chemicals known for their environmental persistence, have been widely used in manufacturing and consumer goods. They are often referred to as “forever chemicals” due to their resistance to degradation in the environment and human body.

The mapping of contamination sites has been a key focus of the PFAS Project Lab for over a decade. Researchers identified early on that known PFAS sites –concentrated in areas like California, New England and Michigan – reflected only the locations where testing is routinely conducted. Many regions of the country remain untested, leading to an incomplete understanding of where PFAS may be present.

To address this, the lab developed a predictive model that identifies likely PFAS contamination based on proximity to the kinds of industrial operations associated with PFAS use. This includes sectors such as metal finishing and electronics manufacturing, where PFAS are commonly involved in production processes.

Airports and military facilities among top contributors

The study categorized potential PFAS-emitting locations into five main types: airports, military facilities, municipal fire activities, industrial facilities and wastewater treatment plants. Among these, the first three showed “consistently had significantly higher PFAS detections than the other site types,” according to the researchers.

One commonality among these high-concentration sites is the use of aqueous film-forming foam (AFFF), a substance which was previously deployed extensively in firefighting operations. AFFF has long been recognized as a significant source of PFAS contamination.

The researchers also note that even among known sites, 94% had average groundwater PFAS levels above accepted regulatory thresholds.

“We did find that, overall, all of the sites that we knew about had elevated PFAS concentrations that were above health-based guidelines. We found that some were associated with really high values, but they were all associated with unacceptable values,” said Kimberly Garrett, a postdoctoral research fellow with the PFAS Project Lab and the lead author of the new research.

Industry scrutiny may help reduce environmental load

While regulatory efforts have focused heavily on water treatment and downstream cleanup, the findings suggest a need to address the industrial origins of PFAS emissions. Metal and electronics manufacturing sites were identified as important, but often overlooked, contributors.

“Metal manufacturers and electronic manufacturers could use a little more scrutiny in that area, especially as we think about making investments in semiconductor manufacturing and things like that,” Garrett said.

By tracing not only contamination sites but also the waste streams that PFAS enter, the team hopes their work will help guide both policymakers and local authorities in prioritizing future testing and remediation. Mapping these pathways also enables communities to identify upstream sources that may be contributing to contamination at water treatment plants.

Filling data gaps to inform public health decisions

Because testing for PFAS remains limited, the lab's model offers a practical tool for targeting resources effectively. For municipalities and states with limited budgets for environmental monitoring, this data-driven approach may help determine where testing efforts will have the greatest impact.

“Once you identify the waste stream, you can also say, ‘Near this wastewater treatment plant are potential manufacturers and users,’” said Phil Brown, co-director of the PFAS Project Lab. “We can then tell them that they have to cut down their emissions before it gets into our [treatment] plants.”

“We know that resources for testing bodies and regulatory bodies and municipal utilities are very limited, so we hope that our tools can serve as a guide for if a municipality or a state has so much money for testing and they say, what would be the most impactful way to use this?” Garrett added. “We think that this paper can contribute to those kinds of decisions.”

Reference: Garrett KK, Say V, Ciaranca S, et al. The landscape of PFAS contamination in the United States: Sources and spatial patterns. Environ Sci Technol. 2025;59(35):18795-18807. doi: 10.1021/acs.est.4c14474

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