Perfluorooctane Sulfonate (PFOS)CAS 1763-23-1
The other big long-chain PFAS — immune suppression, half-life 5-8 years, Stockholm Convention POP.
Toxic Chemical Databases
Substance-specific listings — these flags are for Perfluorooctane Sulfonate alone, not for the broader family.
Chemical Type
Long-Chain C8 Perfluoroalkyl Sulfonate
Chemical Description
PFOS was the active ingredient in Scotchgard and a key constituent of AFFF firefighting foam until 3M phased out production in 2002. Stockholm Convention added PFOS to its POPs list in 2009 — only the second PFAS so listed. The immune-suppression endpoint is the strongest signal — multiple human cohort studies show reduced antibody response to childhood vaccinations. Human serum half-life is even longer than PFOA (5-8 years).
Biological Activity
Severity scores specific to this substance, NOT the parent family average. Differences between siblings are real and meaningful.
Top Health Consequences
- Reduced antibody response to vaccines (well-replicated immune signal)
- Thyroid hormone disruption
- Elevated cholesterol
- Stockholm Convention POP — global ban with exemptions
- Bioaccumulation with 5-8 year human serum half-life
Pathways of Exposure
- Drinking water contamination near military bases and airports
- Legacy stain-treatment exposure from older carpets and upholstery
- Diet — bioaccumulated load in fish
- AFFF firefighting foam residuals at industrial sites
Building Materials with Perfluorooctane Sulfonate
Listed alphabetically — product categories where this specific substance appears.
Legacy Stain-Resistant Carpet
Legacy Stain-Resistant Upholstery
Specialty Surface Treatments