Questions and Answers about PFAS



What are PFAS?

Why are they necessary?
Where are they used?
Why are we concerned with PFAS, instead of other common contaminants like lead?

Polyfluoroalkyl substances (PFAS) are a large family of man-made chemicals. They share in common the fact that all chemical compounds in this family incorporate several atoms of the element fluorine. PFAS are sometimes called PFCs (per- or poly-fluorinated compounds). You might also see specific compounds referred to (e.g., PFOA, PFOS). Two of the chemical compounds in the PFAS family that were the most commonly used and produced are PFOA (also referred to as C8) and PFOS.

Here, we'll use the term PFAS (plural, PFAS) to refer to the larger group of chemicals, unless we are specifically referring to PFOA or PFOS.

PFAS are (or have been) used to make consumer goods resistant to water, grease, or stains, in products like Gore-Tex rain gear, Teflon no-stick cookware, and Scotchguard stain-repellent for carpets or furniture fabric. PFAS are also found in foams used by firefighters to extinguish oil and gas fires. → REFERENCE  BU SPH, PFAS Factsheet → REFERENCE  The New Lead - Perfluorinated Compounds (PFCs)

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How are/were we exposed to PFAS?

See also:
How can I tell whether my water has been contaminted?—see #WATER
How can I tell whether there are PFAS in my body?—see #BLOOD

PFAS are now found almost everywhere in our environment, and it is difficult to quantify how much people are exposed to and exactly how they are exposured. For most people in the USA, who are exposed at so-called "background," or "average", levels of contamination, the primary source of exposure is most likely from consuming foods that were wrapped in PFAS-coated packaging. However, people with higher than average exposure are most likely drinking water that has been contaminated with PFAS.

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How do PFAS travel through the environment?

Is PFAS contamination ongoing, or has it been stopped?
What are the implications of PFAS contamination for new water sources?

Because PFAS are water soluble, the biggest threat of high exposure is through drinking water. Until recently, we thought that only a few water supplies were vulnerable to contamination from large PFAS emissions — for example, the water systems in Ohio and West Virginia that were contaminated on a very large scale by DuPont's Parkersburg, WV facility.

Today, we're finding that many sources can contribute to PFAS in lakes, rivers, or underground aquifers. In some areas, the largest source is when firefighting chemicals, which often contain PFAS, are allowed to run off onto the ground or into a stream. This may not sound like a major source, but firefighter training can use huge volumes of these substances over and over at the same spot — a training facility or an airport, for example. These PFAS-containing foams can then leach into water supplies, contaminating them.

Since PFAS are used for many purposes, there are other, usually smaller, sources. For example, clothes treated with PFAS will leech more PFAS out into the sewer -- and possibly into the groundwater — with every laundry cycle. (Breathable water-proof or water-resistant fabrics are most often treated with PFAS.)

PFAS chemicals are very persistent in the environment, and won't easily break down. This means that once contamination has occurred, the water supply will likely be contaminated for many years to come.

PFOA and PFOS, historically the two most important PFAS chemicals, are no longer made in the USA. However, there are a great many related compounds with similar properties, which may be use Furthermore, stocks of PFAS firefighting foams can be stored for decades, and are likely to be used in firefighting training long into the future, providing future sources of contamination.

What do we know about the health effects of PFAS exposure?

How strong is the scientific link between exposure to PFAS and health outcomes?
Where do PFOAs accumulate in the body?
Why do PFAS show up in some people more than others?

We know that most people living in the US are exposed to at least some level of PFAS chemicals—and many of us are highly exposed. (See #exposed.) But what are the effects of those chemicals on people?

As is the case with many other "emerging contaminants," PFAS have been in use for a long time—many decades, in the case of PFOA and PFOS—but we are only now learning about their health effects. This problem of "using before understanding" occurs regularly because the US does not require testing of most new chemicals before they are used commercially. (For more on the problem of regulating emerging contaminants, see #future.)

The federal Agency For Toxic Substances and Disease Registry lists these health effects as potentially being associated with PFAS exposure in humans: → REFERENCE  Agency For Toxic Substances and Disease Registry, Health Effects of PFAS

Developmental delays in the fetus and child, including possible changes in growth, learning, and behavior;
Decreased fertility and changes to the body's natural hormones;
Increased cholesterol;
Changes to the immune system;
Increased uric acid levels;
Changes in liver enzymes;
Prostate, kidney, and testicular cancer.

Not all of these effects will necessarily lead to disease; changes in liver enzymes may never lead to a liver disease, for example. So there is still uncertainty regarding the significance of some of these changes. However, other effects (e.g., cancers) represent clearer risks. It's also important to note that not everyone is equally susceptible to these effects. For example, developing fetuses and children are much more susceptible to the endocrine disrupting effects on the thyroid, the brain, and the immune system, since those hormonal systems are still being formed and are especially sensitive during development.

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What is still unknown about the risks of PFAS?

PFAS is a large class of chemicals that includes many related compounds. Only PFOA and PFAS have been even moderately well studied thus far.

We are really just getting started learning about the effects of PFAS. In fact, we know there are specific PFAS chemicals already in widespread use that scientists haven't even identified, never mind studied. This is a serious problem with our chemical regulatory system: See #future.

If PFAS are hazardous, how are they regulated?

Now that we know about the contamination, are we still being exposed?

Although PFAS have been in use for decades—and although public health scientists have expressed concerns about them for many years—they have been essentially unregulated until recently.

The US regulatory system does not generally require any testing before new chemicals can be used. Furthermore, in most cases, chemicals cannot be regulated until they are proven to be toxic.

The presence of several large contamination incidents has now created enough public awareness that manufacturers have now voluntarily stopped making the most heavily-used PFAS chemicals. (These chemicals may still be used abroad, however, and these products are still imported to US.) Unfortunately, in most cases, we don't yet know what chemicals are being used to replace them, althought it is very likely that most of the replacements are also PFAS chemicals.

This demonstrates a serious imbalance between government and industry: Manufacturers can change their products at will, but EPA is required to accumulate many years of scientific evidence before regulating a new chemical.

As one scientist recently pointed out, we know that there are PFAS being used out there that we haven't even yet identified!

In November 2016, EPA issued a health advisory for PFOA and PFOS, setting guidance for permissible limits of these chemicals in drinking water. → REFERENCE  US EPA, Drinking Water Health Advisories for PFOA and PFOS

See #safe for details.
For more about regulating chemicals like PFAS, see #future

Is there a test for PFAS contamination in my water?

Where has water been tested?
Can we test the water ourselves?

See also, Should I #filter my water?

Testing water for PFAS contamination is possible, although because PFAS chemicals are so widespread, even collecting a sample to be tested can be a difficult process. While costs vary widely, a test for PFAS in water will cost several hundred dollars.

US EPA Method 537 → REFERENCE  US EPA, Determination of Selected Perfluorinated Alkyl Acids in Drinking Water by Solid Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS) specifies the collection and testing process in great detail, and this process should be followed if results will be used in any official or legal process. While Method 537 provides information on testing for a number of PFAS, it does not test for all of them. Some test facilities may report only PFOA, or PFOA and PFOS, or another limited set of PFAS.

The good news is that, if you are on a public water system, your system managers are responsible for this testing. They may already have test results, or may be able to get them.

If you receive water from a public supply, your water utility is required to provide you with an annual Consumer Confidence Report describing what tests have been performed, and explaining any cases in which the water failed federal water quality requirements. You can find your Consumer Confidence Report through the EPA's search tool, or just try searching for your town's name and the phrase "water quality report" or similar keywords. Check your water system's CCR to find out what levels were measured in your local system, and when and where.

If you're on a well, ask your regular water testing service about testing for PFAS. Be sure to follow up with your local and state departments of health and environment to make sure they are aware of your concerns. In some cases, they may be able to connect you with other resources. If your groundwater is contaminated, it is likely that the whole aquifer—the underground body of water your well draws from—is also contaminated; so it is important that others know about your results.

The New Hampshire Department of Environmental Services has a list of labs that test for PFAS, as well as some laboratory testing guidelines. (Note: Toxics Action Center and the Boston University Superfund Research Program have no experience with these labs, and do not endorse any specific lab.))

For details on how to interpret test results, see #interpret
For the question of what level of PFAS contamation is "safe", see #safe
For information about treating water and reducing your PFAS exposure, see #reduce

Can I have my blood tested for PFAS? Should I/we be tested?

Testing for PFAS in blood is difficult and expensive, and can only be done by a small number of laboratories.

Before testing for PFAS in blood, it may be more useful to identify the sources of the PFAS—for example, by determining whether your drinking water is contaminated. If that's the case, you'll have better information about how you were exposed, and how you can reduce your exposure.

Unfortunately, if you have elevated levels of PFAS in your blood, there is nothing that can be done to remove the PFAS. The best thing you can do is to identify the source of your exposure, and prevent further exposure.

To learn how to reduce your future PFAS exposure, see #reduce.

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My test showed that I have PFAS in my blood. How should I interpret this result?

The extremely widespread use of PFAS means that almost all Americans now have PFAS in their bodies and in their blood. As test methods become more sensitive, we are able to find PFAS at lower and lower levels. Currently, about 99% of Americans tested have detectable levels of PFAS in their blood. Remember, a detectable level of PFAS does not indicate a specific health concern or health risk.

The US federal government's National Health and Nutrition Examination Survey (NHANES) provides a great deal of data on PFAS levels in blood, so anyone can compare their specific results with results from others. This will give you a sense for whether your specific PFAS exposure is high, or medium, or at the "background" level of average everyday exposure. We will discuss this data at #compare below.

Comparing to other people is useful in giving your context about whether your exposure is high or low, in comparison with other who have been tested. But we don't know enough about PFAS to connect any amount in blood with specific health problems, so the blood test itself won't tell you about any specific health concerns that may relate to PFAS exposure now or in the future. Some people might have relatively high amounts of PFAS in their blood, but not have health effects from PFAS, while others might be more susceptible. For example, developing children and fetuses are more susceptible to the endocrine disrupting effects on the thyroid, the brain, or the immune system, since those hormonal systems are still being formed and are especially sensitive. Unfortunately, kids also tend to have higher levels of PFAS exposure than adults do. This might be due to higher exposures (for example, if a kid's diet has more PFAS in packaging materials), or it might be biological (for example, if kids don't metabolize and excrete PFAS as well as adults).

The best thing you can do is to reduce any continued exposure to yourself, your family, and your community. Also, let's try to fix our broken chemical regulatory system so that this problem doesn't happen again. See #future.

Much more detail about the terminology used in interpreting your results is available in the longer answer to this question.

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What is the safe level of PFAS exposure?

How concerned should we be about PFAS in our water or our blood?

When we talk about "safe levels" of exposure, it is critical to distinguish between blood levels and drinking water levels. Someone with a "safe" level of PFAS in their water might still have high levels of PFAS in their blood. In fact, the scientific data indicates that most Americans get the majority of their PFAS exposure from sources other than drinking water.

Unfortunately, we simply don't know enough about the toxicity of PFAS to determine whether a certain amount of PFAS in blood is "safe". The best you can do with blood results is to compare them with others' to see if yours are elevated—see #interpret for more information.

If you receive water from a public supply, your water utility is required to provide you with an annual Consumer Confidence Report describing what tests have been performed, and explaining any cases in which the water failed federal water quality requirements. You can most often find your Consumer Confidence Report online—try searching for your town's name and the phrase "water quality report" or similar keywords.

In November 2016, EPA issued a health advisory for PFOA and PFOS. For more information about this health advisory, see the longer answer to this question.

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What can I do to reduce PFAS exposure and to lower my health risks?

Can I reduce the amount of PFAS already in my body?
How can I reduce future exposures?
Is it safe to shower/bathe in PFAS-contaminated water?
What about food and food packaging?

For specific details on water filtration, see #filter below.

After decades of production and use, about 99% of Americans tested now have detectable levels of PFAS in their blood. Remember, a detectable level of PFAS does not indicate a specific health concern or health risk.


The body will naturally metabolize and excrete PFAS over time. However, this is a very slow process: It is estimated to take 2-4 years to eliminate half of the PFOA from the body. There is no proven way to speed up this elimination of PFAS chemicals from the body. "Toxic eliminating" diets or supplements are not likely to have any effect on PFAS levels.

The persistence of PFAS is one reason why preventing future exposure is so important. For details about how to lower your exposure to PFAS in drinking water, see the longer answer to this question.

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Should I filter my water?

Do commercial filters (e.g. Brita) work for PFAS and other emerging contaminants?
Does boiling water help eliminate PFAS?
Is distilled water safe from PFAS?
Is bottled water safe from PFOA?

Contaminated water can be treated at home by water filters only if they are specifically designed to remove PFAS. Most commercial water filters are not.


Many people see bottled water as a solution—and in cases where the water system is known to be contaminated, it may be necessary. However, bottled water is very poorly regulated. In addition, the environmental footprint of transporting bottled water, and of bottle waste—almost always plastic—is very high. In cases where PFAS contamination can be treated at the source, drinking clear tap water, perhaps treated with a simple activated carbon filter, is usually the most environmentally sound and healthiest approach.

Boiling water is useful to kill living parasites— including bacteria and viruses—in contaminated drinking water. However, this approach isn't effective with most toxics. PFAS is quite stable and persistent, and boiling water is unlikely to remove any significant amount of it.

While filtration may be useful, the best approach for significantly contaminated water will be to make sure your water supplier manages contamination of the aquifer at the source. See #reduce and #water for more information.

How can my community respond to this contamination?

First, get informed!

If you know or suspect that your community's water has been contaminated with PFAS, a good starting place is to get your #water tested. Be sure to check the #CCR published by your water supplier for information on what testing they've already done. If your water supply is not testing for PFAS, pressure your local government to have the water tested. If your water is contaminated, be sure your state and local health officials know about the problem. If the contamination is below the EPA's #advisory, they may not be willing (or required) to act. However, check guidance from other states and localities to see if you exceed guidelines set elsewhere.

It's important to identify the source of contamination. Are there major sources—for example, heavy use of fire-fighting foams—in your area? If the source is not already known, your state and local health officials may be able to help you track it down. If your water is contaminated, you may want to have your #blood tested as well. Remember, testing—especially blood testing—is expensive. Talk to your state and local officials about setting up a monitoring program.

Get organized!

You can't respond to contamination alone—you'll need the help of your neighbors and friends, as well as scientists and government officials. You need to organize! A number of resources exist to help your community get organized to fight pollution. If you know of groups in your area, contact them and ask for help. You can always contact Toxics Action Center for connections and next steps.

In addition to organizing help, you may need expert assistance to help your community understand their contamination, the possible effects, and the best ways to respond. Consider contacting local colleges and universities (especially schools of public health) for assistance. Toxics Action Center, and other that focus on community health and environmental justice, should also be able to connect you with scientists who can help.

Is a health study right for your community?

Many communities immediately decide that they need the state to perform a health study of their community to evaluate the effect of the pollution. While a health study can provide important information, it might also prove inconclusive, and in either case it is likely to take a substantial investment of time and resources.

If you've done the basic background work above, and you think that a health study is the right next step, see our guide, Is a Health Study Right for Your Community?. This guide will help you establish your research question and develop the best study to answer your community's questions.

How can we make sure contamination like this doesn't happen in the future?

What can we do to promote responsible chemical use & development?
How can chemists find safer chemicals?
Are the C6 chemicals good replacements for the C8 PFAS chemicals

The current situation—in which millions of Americans are exposed to PFOA, PFOS, and probably to other PFAS in their drinking water—should never have happened. → REFERENCE  'Unsafe levels of toxic chemicals found in drinking water for six million Americans'

It happened because we allowed a chemical to be used widely and at high volumes before we had adequately tested it. This is not an isolated incident or a one-time occurance. The same thing happened with leaded gasoline, and with lead in paint. The same thing happened with flame retardants and with bisphenol A. Incidents like these, and many more, happen because of the design of the US regulatory system, which over the past 40 years has not required companies to test chemicals before using them. (This situation may now be changing; see below for information on changes to federal regulations.)

By contrast, European chemicals regulation requires extensive testing for human and environmental health effects before a chemical can be placed on the market—summed up in the simple phrase, "no data, no market".

The difference between these two systems lies in who has the burden of proof. In Europe, a chemical manufacturer must prove a chemical safe before it is used. In the US, the government must prove that a chemical is harmful before its use can be stopped.

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