Monitored — not federally regulated
6:2 FTS
6:2 Fluorotelomer sulfonic acid
Often the dominant PFAS at AFFF-contaminated sites — the active replacement for older PFOS-based firefighting foam. Can transform into PFHxA in the environment, complicating long-term contamination tracking.
01Health effects
Linked outcomes
- · Liver effects
- · Thyroid disruption
- · Kidney toxicity
- · Potential developmental effects
Organs affected
Liver, thyroid, kidneys
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
Major component of modern AFFF firefighting foams. Found at high concentrations around military bases, airports, and fire training sites. Also used in chrome plating.
03Regulatory status
Not federally regulated. The Department of Defense is phasing out fluorinated AFFF for civilian airport firefighting, but 6:2 FTS-based foams remain in use at some military installations.
04What you can do
If 6:2 FTS 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.
- 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.