pfasUCMR5Unregulated by EPA

8:2 FTS (8:2 fluorotelomer sulfonic acid)

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

8:2 FTS is an eight-carbon fluorotelomer sulfonic acid. It is used in AFFF firefighting foam and industrial surface-treatment products. Its longer chain compared to 6:2 FTS results in greater potential for bioaccumulation. It can degrade to PFOA and other long-chain perfluorocarboxylic acids in the environment.

CAS 39108-34-4

EPA legal limit

No federal limit

Maximum Contaminant Level

EWG health guideline

No guideline

Science-based, stricter target

Health effects

8:2 FTS degrades to PFOA and other long-chain PFAS, meaning its presence in drinking water contributes indirectly to regulated PFAS body burden. Animal studies show liver and thyroid effects. Its eight-carbon chain gives it greater bioaccumulation potential than shorter FTS compounds.

Where it comes from

Used in AFFF firefighting foam at military installations and airports. Also found in industrial fluorochemical processing. Its presence in drinking water is strongly associated with AFFF-contaminated groundwater sources.

How it's regulated

No federal EPA MCL. Not regulated under the 2024 PFAS NPDWR. Monitored under UCMR5. No EWG health guideline established. Notably, it degrades to PFOA — a compound regulated at 4 ppt under the 2024 NPDWR.

How to filter 8:2 fts

Not all filters address 8:2 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 8:2 fts?

8:2 FTS is an eight-carbon fluorotelomer sulfonic acid. It is used in AFFF firefighting foam and industrial surface-treatment products. Its longer chain compared to 6:2 FTS results in greater potential for bioaccumulation. It can degrade to PFOA and other long-chain perfluorocarboxylic acids in the environment.

What are the health effects of 8:2 fts?

8:2 FTS degrades to PFOA and other long-chain PFAS, meaning its presence in drinking water contributes indirectly to regulated PFAS body burden. Animal studies show liver and thyroid effects. Its eight-carbon chain gives it greater bioaccumulation potential than shorter FTS compounds.

Is 8:2 fts regulated in drinking water?

No federal EPA MCL. Not regulated under the 2024 PFAS NPDWR. Monitored under UCMR5. No EWG health guideline established. Notably, it degrades to PFOA — a compound regulated at 4 ppt under the 2024 NPDWR.

Where does 8:2 fts come from?

Used in AFFF firefighting foam at military installations and airports. Also found in industrial fluorochemical processing. Its presence in drinking water is strongly associated with AFFF-contaminated groundwater sources.

How do I remove 8:2 fts from tap water?

The most effective methods for removing 8:2 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 8:2 fts in your water?

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