What is PFOS?
PFOS (perfluorooctane sulfonate), along with a similar chemical known as PFOA (perfluorooctanoic acid), are part of a class of chemicals known as perfluorinated compounds (PFCs). PFCs have been used in a number of industrial and commercial products such firefighting foam, as well as coatings that repel water, oil, stains and grease. They have been used in textiles, food packaging and non-stick cookware; though many major manufacturers in the United States have agreed to voluntarily reduce the content of PFCs in their products.
Information About PFOS and PFOA in Drinking Water
Is there a drinking water standard for PFOS or PFOA?
There are currently no chemical-specific federal or New York State drinking water standards for PFOS or PFOA; however they are both regulated as Unspecified Organic Contaminants by the New York State Department of Health (NYSDOH) at a level of 50 parts per billion (ppb). The concentrations detected in the groundwater in Suffolk County have not exceeded this level.
Are there chemical-specific guidelines for PFOS and PFOA in drinking water?
Yes. In May of 2016 the US EPA developed a health advisory for PFOS and PFOA. Health advisories are non-enforceable, non-regulatory levels in drinking water that are developed by the US EPA to provide information on contaminants that may be found in drinking water. They provide information on potential health risks from exposure to a chemical. In addition, the health advisories provide information on appropriate actions that can be taken when chemicals are detected in drinking water.
The drinking water health advisory level for PFOS and PFOA is 0.07 parts per billion (ppb), which is the same as 70 parts per trillion (ppt). When both PFOA and PFOS are detected in a water supply, the combined concentration should be compared to the 0.07 ppb health advisory. This health advisory has been established to provide everyone, including the most sensitive populations (developing fetus and infants who may be breastfed or fed formula mixed with water), with a margin of protection from exposure to PFOS and PFOA in drinking water, even if that exposure were to occur throughout their life.
Can exposure to PFOS and PFOA affect my health?
The US EPA evaluated the current evidence from studies in laboratory animals (rats and mice) as well as reviewed disease incidence (epidemiological studies) in humans that may have been exposed to PFOA and PFOS and determined that exposure to PFOS and PFOA may result in adverse health effects, depending upon the amount and duration of exposure. These studies indicated potential risks to the developing fetus if exposure occurs over certain levels during pregnancy, as well as effects to breastfed infants whose mothers may drink contaminated water. These effects include low birth weight, early puberty, and skeletal variations. For the general population, exposure at sufficient levels could increase the risk of developing cancer (specifically testicular and kidney), as well as effects on the liver, thyroid, immune system and changes in cholesterol levels. For more information see the USEPA Health Advisory Fact Sheet at
Are there other sources of exposure to PFOS and PFOA in addition to drinking water?
Yes. Because PFOS and PFOA have been used in many products, people can be exposed from many sources other than drinking water. The general public can be exposed from contact with soil, dust, air and water contaminated with PFOS and PFOA. Food can be a significant source of exposure to PFOS and PFOA, and carpets that treated with PFC-containing products would also be a potential source of exposure for small children.
In 2006, the US EPA invited the major United States manufacturers of PFCs to participate in a Stewardship Program. The companies committed toward eliminating emissions and product content by 2015. Participating companies have met the program goals. (Information on the program is available at
If my drinking water had concentrations of PFOS or PFOA above the US EPA Health Advisory will my health be adversely affected?
The US EPA health advisory level does not represent the concentration in drinking water above which health effects are expected. The health advisory level, 0.07 ppb, was established, with a margin of protection, at a concentration in water that is not anticipated to result in adverse health effects if an individual consumes water containing that concentration over the course of their lifetime. It is also designed to be protective of pregnant and nursing mothers, who may consume more water than an average person.
As the concentration in drinking water increases above the health advisory, the margin of protection is diminished and the level of comfort that health effects will not occur decreases. Therefore, if your water is above the health advisory level, it is recommended that you take steps to reduce your exposure to PFOS or PFOA by using alternate water for consumption.
If my water contains PFOS or PFOA is it OK to use it to shower or bathe?
Showering or bathing does not appear to be a significant source of exposure to PFOS or PFOA.
Is there a blood test that can determine whether I have been exposed to PFOS or PFOA?
PFOS and PFOA can be measured in blood, though it is not a routine test that can be performed in a doctor’s office or commercial laboratory. A blood test would show whether a person has been exposed. Studies have shown that a large proportion of the general population have detectable levels of PFOA and PFOS in our blood due to the widespread exposure to these substances. However, those results do not mean the person will develop an adverse health effect. There is not yet enough information to know what level of PFOA or PFOS in blood may be associated with adverse health effects. In addition, a blood test will not identify whether the source of the PFOS or PFOA exposure is from drinking water or other sources.
Contacts for more information
- For general questions about PFOS or PFOA and health, contact New York State Department of Health at 1-518-402-7860.
- Residents who have questions about private well water in Suffolk County or would like to have their wells tested, contact the SCDHS Office of Water Resources at 631-852-5810.
- Residents may wish to contact the Suffolk County Water Authority at 631-698-9500:
- For information on the environmental investigation at the Air National Guard Base, contact John Swartwout, Division of Environmental Remediation, NYSDEC at 518-402-9620.
For information on the environmental investigation at the Firematics Site, contact Robert Corcoran, Division of Environmental Remediation, NYSDEC at 518-402-9658.