pfasUCMR5Unregulated by EPA

6:2 FTS (6:2 fluorotelomer sulfonic acid)

Reviewed for accuracy against EPA data and peer-reviewed literature · Updated May 2026

6:2 FTS is the most widely detected fluorotelomer sulfonic acid in drinking water. It is a six-carbon FTS compound used extensively in AFFF firefighting foam and as a surfactant in industrial applications. The "6:2" designation refers to six perfluorinated carbons and two non-fluorinated carbons.

CAS 27619-97-2

EPA legal limit

No federal limit

Maximum Contaminant Level

EWG health guideline

No guideline

Science-based, stricter target

Health effects

6:2 FTS can degrade to PFBS and other short-chain PFAS in the environment. Animal studies show liver effects and thyroid disruption. It is found in AFFF-contaminated drinking water at relatively higher concentrations than other FTS compounds. Its degradation products add to the cumulative PFAS burden in exposed communities.

Where it comes from

Primary source is AFFF firefighting foam at military bases, airports, and fire training facilities. Also used in industrial fluorinated surfactant applications. Among the most commonly detected FTS compounds in UCMR5 data near AFFF-use sites.

How it's regulated

No federal EPA MCL. Not regulated under the 2024 PFAS NPDWR. Monitored under UCMR5. No EWG health guideline established. Among the most prevalent FTS compounds in US drinking water near AFFF contamination sites.

How to filter 6:2 fts

Not all filters address 6:2 fts. Look for independently certified filters—NSF International certification means the removal claim has been independently verified.

Reverse osmosis (RO)NSF 58
NSF 58 certified RO system
Activated carbon block filterNSF 53

Frequently asked questions

What is 6:2 fts?

6:2 FTS is the most widely detected fluorotelomer sulfonic acid in drinking water. It is a six-carbon FTS compound used extensively in AFFF firefighting foam and as a surfactant in industrial applications. The "6:2" designation refers to six perfluorinated carbons and two non-fluorinated carbons.

What are the health effects of 6:2 fts?

6:2 FTS can degrade to PFBS and other short-chain PFAS in the environment. Animal studies show liver effects and thyroid disruption. It is found in AFFF-contaminated drinking water at relatively higher concentrations than other FTS compounds. Its degradation products add to the cumulative PFAS burden in exposed communities.

Is 6:2 fts regulated in drinking water?

No federal EPA MCL. Not regulated under the 2024 PFAS NPDWR. Monitored under UCMR5. No EWG health guideline established. Among the most prevalent FTS compounds in US drinking water near AFFF contamination sites.

Where does 6:2 fts come from?

Primary source is AFFF firefighting foam at military bases, airports, and fire training facilities. Also used in industrial fluorinated surfactant applications. Among the most commonly detected FTS compounds in UCMR5 data near AFFF-use sites.

How do I remove 6:2 fts from tap water?

The most effective methods for removing 6:2 fts are: Reverse osmosis (RO), NSF 58 certified RO system, Activated carbon block filter. Look for NSF-certified systems—independent certification confirms removal claims have been verified.

Is 6:2 fts in your water?

Enter your ZIP code to see the measured level in your specific utility.