EPA legal limit
No federal limit
Maximum Contaminant Level
EWG health guideline
No guideline
Science-based, stricter target
Health effects
Limited toxicological data. Available studies suggest thyroid and liver effects consistent with other PFAS. As a Cl-PFESA compound structurally related to PFOS, it is likely to share aspects of PFOS toxicity. It has been detected in the blood of workers in electroplating industries and in wildlife in contaminated regions.
Where it comes from
Used in metal plating as a PFOS replacement, primarily in Asian manufacturing. Detected in global surface water bodies and in US drinking water via long-range transport and domestic electroplating sources.
How it's regulated
No federal EPA MCL. Not regulated under the 2024 PFAS NPDWR. Monitored under UCMR5. No EWG health guideline established.
How to filter 9cl-pf3ons
Not all filters address 9cl-pf3ons. Look for independently certified filters—NSF International certification means the removal claim has been independently verified.
Frequently asked questions
What is 9cl-pf3ons?
9Cl-PF3ONS is a chlorinated ether PFAS compound included in UCMR5 monitoring. Like its analogue 11Cl-PF3OUdS, it belongs to the Cl-PFESA class used as PFOS replacements in electroplating. Its detection in US water systems reflects global PFAS contamination and industrial transport pathways.
What are the health effects of 9cl-pf3ons?
Limited toxicological data. Available studies suggest thyroid and liver effects consistent with other PFAS. As a Cl-PFESA compound structurally related to PFOS, it is likely to share aspects of PFOS toxicity. It has been detected in the blood of workers in electroplating industries and in wildlife in contaminated regions.
Is 9cl-pf3ons regulated in drinking water?
No federal EPA MCL. Not regulated under the 2024 PFAS NPDWR. Monitored under UCMR5. No EWG health guideline established.
Where does 9cl-pf3ons come from?
Used in metal plating as a PFOS replacement, primarily in Asian manufacturing. Detected in global surface water bodies and in US drinking water via long-range transport and domestic electroplating sources.
How do I remove 9cl-pf3ons from tap water?
The most effective methods for removing 9cl-pf3ons are: Reverse osmosis (RO), NSF 58 certified RO system. Look for NSF-certified systems—independent certification confirms removal claims have been verified.
Is 9cl-pf3ons in your water?
Enter your ZIP code to see the measured level in your specific utility.