Key points
- Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals used in industry and consumer products worldwide since the 1940s.
- PFAS use and presence in the environment are widespread and found in the blood of people and animals all over the world and are present at low levels in a variety of food products and in the environment.
- Scientists are still learning about the health effects of exposures to mixtures of different PFAS.
What are PFAS?
Statement on potential intersection between PFAS exposure and COVID-19:
CDC/ATSDR understands that many of the communities we are engaged with are concerned about how PFAS exposure may affect their risk of COVID-19 infection. We agree that this is an important question. CDC/ATSDR recognizes that exposure to high levels of PFAS may impact the immune system.
A National Toxicology Program review found that exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) is an immune hazard to humans based on a high level of evidence that PFOA and PFOS suppressed the antibody response from animals and a moderate level of evidence from studies in humans (NTP, 2016). More research is needed to understand how PFAS exposure may affect illness from COVID-19.
Per- and polyfluoroalkyl substances (PFAS) are man-made chemicals. They've been used in industry and consumer products worldwide since the 1940s. PFAS have been used to make:
- Water-repellent clothing
- Stain-resistant fabrics and carpets
- Some cosmetics
- Some firefighting foams
- Grease-, water-, and oil-resistant products
PFAS can migrate into the soil, water, and air when produced and used.
- Most (including PFOA and PFOS) don't break down.
- The result is PFAS enter the blood of people and animals worldwide.
- PFAS can be present at low levels in a variety of food products.
- They can also build up in the body with each exposure over time.
Scientific articles have been published about PFAS exposure and health effects. It is difficult to show that substances directly cause health conditions in humans. Yet, scientific studies suggest that exposure to some PFAS may be linked to harmful health effects in humans and animals. More research is needed to better understand the health effects of PFAS exposure.
Common types
The most commonly studied PFAS are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). The next most commonly studied are perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA). PFOA and PFOS have been phased out of production in the U.S. Other countries may still manufacture and use them.
New kinds of PFAS are being developed. Some may have properties similar to the existing PFAS. Others may be less persistent in the environment. There are very few scientific studies on new PFAS, so more research is necessary to discover whether they may be a health concern.
Exposure to PFAS
Exposure happens when a person breathes, eats, drinks, or touches a chemical and it enters their body. Exposure can occur from:
- Living near sites with contaminated air, soil, or drinking water.
- Eating food grown or raised near places that used or made PFAS.
- Eating fish or wild game contaminated by PFAS (notably PFOS).
- Accidentally swallowing contaminated soil or dust.
- Eating food packaged in material that contains PFAS.
- Using products like stain-resistant carpet or water-repellent clothes.
- Inhaling PFAS (manufacturing chemicals or using fire-fighting foam).
For most PFAS, showering and bathing in water containing PFAS should not significantly increase exposure.
Babies born to mothers who were exposed to PFAS can also be exposed:
- Before they are born
- While breastfeeding
- Drinking formula mixed with PFAS-contaminated water.
How PFAS can leave the body
Excretion is the process whereby substances, like PFAS, leave the body. At this time, we are unable to use PFAS blood levels to decide what harmful effects might be possible.
PFAS can be measured in the blood. Your PFAS blood levels will show the amount in your body. This is determined by how much PFAS you have been exposed to (exposure), minus how much PFAS have left your body (excretion).
Exposure and excretion are different for each person. For example, two members of the same household may have very different PFAS levels in their bodies.
Some PFAS leave the body slowly over time. Mostly, this is through urine. People who have kidney disease may not excrete as much from their body as healthy individuals.
Other PFAS routinely leave the body in blood during menstruation. Those who menstruate may excrete more PFAS than those who do not.
Some can leave in breastmilk. People who breastfeed may excrete more PFAS from their bodies than those who do not. All of these factors could affect PFAS levels measured in your blood.
What CDC is doing
ATSDR is committed to reviewing the science on PFAS and providing evidence-based information as it becomes available.
- The map of ATSDR sites provides specific information about a site.
- Exposure Assessments in communities near current or former military bases
- Health Studies are being conducted with cooperative agreement partners on the effects of PFAS exposure.
- NTP (National Toxicology Program). 2016. Monograph on Immunotoxicity Associated with Exposure to Perfluorooctanoic acid (PFOA) and Perfluorooctane Sulfonate (PFOS).