Question 1

What is Perfluorononane Sulfonic Acid?

Accepted Answer

Perfluorononane Sulfonic Acid (PFNS) is a per- and polyfluoroalkyl substance (PFAS) – a synthetic chemical used in manufacturing, firefighting foam, and consumer products. It persists indefinitely in water and the human body.

Question 2

Is PFNS in my drinking water?

Accepted Answer

EPA UCMR5 testing (2023-2025) monitors PFNS at 6,800+ US water systems. Enter your ZIP code at KnowYourExposure.com to see if PFNS has been detected in your specific utility.

Question 3

What is the EPA limit for PFNS?

Accepted Answer

Not all PFAS compounds have federal limits yet. The EPA's 2024 PFAS Rule set limits for 6 compounds including PFOA, PFOS, PFHxS, PFNA, and HFPO-DA. Others are still under review.

Question 4

What are the health effects of PFNS?

Accepted Answer

PFNS exposure has been linked to: Expected bioaccumulation, Potential immune and liver effects. Long-term exposure increases risks even at low doses.

Question 5

How do I remove PFNS from my water?

Accepted Answer

Certified reverse osmosis systems remove 90%+ of most PFAS including PFNS. Activated carbon and ion exchange filters also work. Boiling does NOT remove PFAS – it concentrates them.

Question 6

What is the CAS number for Perfluorononane Sulfonic Acid?

Accepted Answer

The CAS Registry Number for Perfluorononane Sulfonic Acid is 68259-12-1.

PFNS: Health Effects, EPA Limits & Sources (2026)