What you may have heard
Exposure to per- and polyfluoroalkyl substances (PFAS), such as PFOA and PFOS, might increase your risk of cancer.
What the science tells us
PFOA (Perfluorooctanoic Acid) and PFOS (Perfluorooctane Sulfonate) are part of a larger group of man-made chemicals known as per- and polyfluoroalkyl substances (PFAS). These chemicals have been in commercial use since the 1940s due to their unique properties that make them resistant to heat, water, oil, and stains.
Where are they found?
- Consumer Products: Commonly used in the production of non-stick cookware (like Teflon), water-resistant clothing, sun-protective clothing (UPF clothing), stain-resistant fabrics and carpets.
- Industrial Sites: Used in firefighting foams, and other industrial applications.
- Water Sources: Contaminated drinking water supplies near industrial sites, military bases, and areas where firefighting foams have been extensively used.
- Food: Food packaging and some foods, particularly certain types of seafood and products from contaminated areas, can contain low levels of PFAS.
Epidemiological Evidence:
- Kidney Cancer: Studies have shown an increased risk of renal cell carcinoma (RCC) among individuals with high PFOA exposure, particularly those working in chemical plants or living near contaminated water sources. However, results vary across different population groups.
- Testicular Cancer: Research indicates elevated PFOS levels are associated with a higher risk of testicular cancer, especially among military personnel exposed to PFAS through firefighting foams.
- Breast Cancer: Some studies have found a link between PFOS exposure and hormone receptor-positive breast cancer in postmenopausal women, though more research is needed to confirm these findings.
Laboratory Evidence/Supporting Evidence:
- Experiments on lab animals have demonstrated that PFAS exposure can lead to tumors in organs such as the liver, pancreas, and mammary glands. These findings suggest potential carcinogenic effects, but translating these results to humans requires further investigation.
IARC Carcinogen Classification:
- PFOA is classified as “carcinogenic to humans” (Group 1) based on sufficient evidence from animal studies and strong evidence of its carcinogenic properties in humans.
- PFOS is classified as “possibly carcinogenic to humans” (Group 2B) due to limited evidence in humans but sufficient evidence in animal studies.
How to reduce your risk
- Avoid contaminated water. Use bottled water or activated carbon filters if you live in areas with known PFAS contamination.
- Reduce consumption of foods known to be contaminated with PFAS, such as certain seafood and canned clams.
- Limit the use of products that may contain PFAS, such as non-stick cookware, stain-resistant fabrics, and certain food packaging materials.
- PFOA and some closely related chemicals (such as PFOS) are now no longer made in the US, although they are still made in some other countries and could potentially reach US consumers in certain types of products. Being aware of product origins and regulatory updates can help in making safer choices.
Bottom line
While there is growing evidence suggesting that PFAS exposure is linked to certain cancers, definitive conclusions from the scientific community affirm that there is a significant cause for concern. Continued research is essential to fully understand the risks and develop effective strategies for reducing exposure. Being aware of potential sources of PFAS and taking steps to minimize contact can help mitigate potential health risks.
Watch this short video on the link between PFAS and cancer by the Dana-Farber Cancer Institute.