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Recall Alert

There is a voluntary recall of Potassium Chloride Extended-Release Capsules. Learn more

Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS)

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of manmade chemicals that have been used in many fields of work around the world. The United States has been using them since the 1940s.

There are over 4,000 PFAS compounds. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) have been the most widely produced and studied. PFOA and PFOS do not break down and can collect in the body and in nature over time. PFOA and PFOS are no longer made in the United States. Yet, they are still made in other countries and imported into the US.

How can I be exposed to PFAS?

People can come in contact with PFAS by:

  • eating or drinking items that have PFAS
  • using some consumer products
  • breastfeeding and during pregnancy (mother to baby)
  • breathing dust that has PFAS

PFAS and health

Scientists are still learning how these chemicals affect people’s health. Some studies show a possible link between PFAS and some health problems, including:

  • lowering the body’s ability to fight off infection
  • increases in cholesterol levels in the blood
  • cancers in the liver, kidneys, and testicles

PFAS standards

Lifetime Health Advisories (LHAs)

On May 19, 2016, the United States Environmental Protection Agency (EPA) issued LHAs for two PFAS substances:

  1. PFOA
  2. PFOS 

These advisories are non-regulatory and provide information on human health effects from a lifetime of exposure to PFOA and PFOS from drinking water.

The lifetime health advisory level is a combined 70 parts per trillion for both PFOA and PFOS.

Compound LHAs
PFOA 70 ppt
PFOS 70 ppt


Updated interim LHAs

In 2022, the EPA released updated interim health advisories for PFOA and PFOS, which were based on human epidemiology studies in populations exposed to these chemicals.

Based on those studies and EPA’s draft analyses, the levels at which negative health effects could occur were much lower than previously understood.

The 2022 updated interim health advisories replaced the 2016 health advisories for PFOA and PFOS.

New LHAs

In 2022, the EPA also released LHAs for two additional PFAS chemicals:

  • Hexafluoropropylene oxide dimer acid
    (HFPO-DA, commonly known as GenX Chemicals)
  • Perfluorobutane sulfonic acid (PFBS)

The lifetime health advisories for GenX Chemicals and PFBS are based on animal toxicity studies following oral exposure to these chemicals.

New and updated interim LHAs

Compound LHAs
PFOA 0.004 ppt (interim)
PFOS 0.02 ppt (interim)
GenX Chemicals 10 ppt
PFBS 2,000 ppt


National Primary Drinking Water Regulations (NPDWRs)

On March 14, 2023, the EPA announced proposed NPDWRs for six PFAS including:

  1. PFOA
  2. PFOS
  3. GenX Chemicals
  4. PFBS
  5. Perfluorononanoic acid (PFNA)
  6. Perfluorohexane sulfonic acid (PFHxS)

Proposed Maximum Contaminant Levels (MCLs)

These NPDWRs propose establishing legally enforceable levels, called MCLs for six PFAS in drinking water.

PFOA and PFOS are regulated as individual contaminants.

PFHxS, PFNA, PFBS, and GenX Chemicals are regulated as a PFAS mixture.

Compound Proposed MCLs
PFOA 4.0 ppt
PFOS 4.0 ppt
GenX Chemicals 1.0 (unitless) hazard index
PFBS 1.0 (unitless) hazard index
PFNA 1.0 (unitless) hazard index
PFHxS 1.0 (unitless) hazard index


Proposed Maximum Contaminant Level Goals (MCLGs)

EPA is also proposing health-based, non-enforceable MCLGs for these six PFAS.

As part of the proposed NPDWR, the proposed MCLGs for both PFOA & PFOS are 0.0 ppt, based on agency policy for chemicals that have been classified as “likely human carcinogens.”

Compound Proposed MCLGs
PFOA 0.0 ppt
PFOS 0.0 ppt
GenX Chemicals 1.0 (unitless) hazard index
PFBS 1.0 (unitless) hazard index
PFNA 1.0 (unitless) hazard index
PFHxS 1.0 (unitless) hazard index


State standards

State governments are now making their own drinking water standards for PFAS. Some of these are stricter than the federal guidelines and include additional PFAS chemicals. Since 2016, PFAS have been found in public and private drinking water across the country. Some at levels higher than the federal and state advice.

For more information on PFAS in your state

Clinician resource

In January 2024, the Centers for Disease Control and Prevention (CDC) and the Agency for Toxic Substances and Disease Registry (ATSDR) released PFAS: Information for Clinicians. This document provides updated information for clinicians to consider when seeing patients who have concerns about per- and polyfluoroalkyl substances (PFAS) exposure or possible health effects.

Additional resources

Below are some additional resources for PFAS.