Monitored — not federally regulated
PFDA
Perfluorodecanoic acid
A long-chain PFAS with an estimated human half-life of 7–12 years — among the most persistent compounds in the body of any monitored PFAS. Frequently detected in human blood samples even decades after primary uses ended.
01Health effects
Linked outcomes
- · Liver damage
- · Immune suppression
- · Thyroid disruption
- · Reproductive toxicity
- · Potential carcinogen
Organs affected
Liver, immune system, thyroid, reproductive system
Effects above are summarized from EPA, NIH/NTP, ATSDR, and IARC documentation. Not a clinical or medical claim — see our sourcing standards.
02Where it comes from
Byproduct of fluoropolymer manufacturing. Often found alongside PFOA and PFOS at contaminated sites. Present in some food packaging and industrial coatings.
03Regulatory status
Not federally regulated, but bioaccumulates more than PFOA and is frequently detected in human blood samples. Likely candidate for future EPA regulation.
04What you can do
If PFDA was detected in your water supply, two filter technologies reliably remove it at the tap:
- RO (reverse osmosis) under-sink systems — 90–99.9% removal across all PFAS chain lengths. Look for NSF/ANSI 58 certification.
- GAC (granular activated carbon) block filters — effective for long-chain PFAS; less reliable for short-chain compounds. Look for NSF/ANSI 53 with NSF P473.
See our certified-filter picks or read the in-depth PFAS removal guide.
Related compounds
Other monitored compounds
- PFBS →
Perfluorobutane sulfonic acid
Introduced as a shorter-chain PFOS replacement after 3M phased out PFOS in 2002. The shorter chain clears the body faster but is harder to filter out of water.
- PFHxA →
Perfluorohexanoic acid
One of the most frequently detected PFAS in US drinking water and a common degradation product of fluorotelomer chemistry used in food packaging and stain protection. Its short chain length makes it especially hard to remove with activated carbon filters.
- PFBA →
Perfluorobutanoic acid
Very short half-life in the body (3–4 days) compared to PFOA (years), but still persistent in the environment. Often the final breakdown product when longer-chain PFAS degrade.
- PFUnA →
Perfluoroundecanoic acid
One of the longest-chain PFAS in the UCMR 5 monitoring set — extremely persistent in both the environment and the human body. Often used by researchers as a marker of fluoropolymer manufacturing emissions.