HFPO-DA
Hexafluoropropylene oxide dimer acid
- EPA federal limit
- 10 ppt
- Detected in
- 10,289 systems
- Exceeds limit in
- 13 systems
What is HFPO-DA?
Hexafluoropropylene oxide dimer acid, or HFPO-DA, is a man-made chemical that belongs to the PFAS family, a group of substances often called "forever chemicals" because they break down very slowly in the environment and can build up in the body over time. HFPO-DA was developed as a replacement for older PFAS compounds, like PFOA, that were phased out due to health concerns. Unfortunately, research suggests that being a replacement does not necessarily make it safer.
Where does it come from?
HFPO-DA is used in industrial manufacturing processes, particularly in making non-stick coatings for cookware and stain-resistant treatments for fabrics and carpets. It can also be released into the air and water near chemical manufacturing plants. Communities located close to facilities that produce fluorinated chemicals are at higher risk of exposure through their drinking water.
Health concerns
Research on HFPO-DA is still in early stages, and published data on human health effects is limited. Animal studies have associated HFPO-DA with liver damage, kidney problems, and developmental effects during pregnancy, according to EPA research. Because most findings come from animal studies rather than large human studies, scientists consider the evidence preliminary. If you have specific health concerns, consult a healthcare provider.
EPA standard
The EPA set a Maximum Contaminant Level, or MCL, for HFPO-DA at 10 parts per trillion (ppt) in 2024. An MCL is the highest amount of a contaminant legally allowed in public drinking water. This means water utilities must test for HFPO-DA and take action if levels exceed this limit.
What you can do
If HFPO-DA is detected in your water, the most effective option is a reverse osmosis filter, which research studies and the EPA confirm can significantly reduce PFAS levels including HFPO-DA. Granular activated carbon filters may also help, though they are generally less effective than reverse osmosis. Remember that boiling water does not remove PFAS compounds and may actually concentrate them.
About this summary: Narrative text on this page was drafted by an AI model (claude-sonnet-4-6) from EPA UCMR 5 data and reviewed before publication. The numeric data above is reported by water utilities directly to the EPA. If you spot an error, email data@checkyourwater.org.