Question 1

What is 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic Acid?

Accepted Answer

11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic Acid (11Cl-PF3OUdS) 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 11Cl-PF3OUdS in my drinking water?

Accepted Answer

EPA UCMR5 testing (2023-2025) monitors 11Cl-PF3OUdS at 6,800+ US water systems. Enter your ZIP code at KnowYourExposure.com to see if 11Cl-PF3OUdS has been detected in your specific utility.

Question 3

What is the EPA limit for 11Cl-PF3OUdS?

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 11Cl-PF3OUdS?

Accepted Answer

11Cl-PF3OUdS exposure has been linked to: Unknown; structural characteristics suggest persistence. Long-term exposure increases risks even at low doses.

Question 5

How do I remove 11Cl-PF3OUdS from my water?

Accepted Answer

Certified reverse osmosis systems remove 90%+ of most PFAS including 11Cl-PF3OUdS. Activated carbon and ion exchange filters also work. Boiling does NOT remove PFAS – it concentrates them.

Question 6

What is the CAS number for 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic Acid?

Accepted Answer

The CAS Registry Number for 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic Acid is 763051-92-9.

11Cl-PF3OUdS: Health Effects, EPA Limits & Sources (2026)