Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock ( Lock A locked padlock ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

  • Environmental Topics
  • Laws & Regulations
  • Report a Violation
  • About EPA
IRIS
Contact Us

Perfluorohexanesulfonic Acid (PFHxS)

CASRN 355-46-4 | DTXSID7040150

  • Toxicological Review (PDF) (493 pp, 24.04 M)
  • IRIS Summary (PDF) (6 pp, 413 K)

On this page:

  • Key IRIS
    Values
  • Organ/System
    Specific Values
  • Chemical
    Documents
  • Other EPA
    Information

Noncancer Assessment

Reference Dose for Oral Exposure (RfD) (PDF) (6 pp, 413 K) Last Updated:

System RfD (mg/kg-day) Basis PoD Composite UF Confidence
Developmental, Immune 4 x 10 -10
(Chronic)
Decreased serum anti-tetanus antibody concentration in children at age 7 yrs (Grandjean et al., 2012; Budtz-Jorgensen and Grandjean, 2018) BMDL (HED): 1.16 x 10-8
mg/kg-day
30
MF: None
Medium

Reference Concentration for Inhalation Exposure (RfC) (PDF) (6 pp, 413 K)

System RfC (mg/m3) Basis PoD Composite UF Confidence

Cancer Assessment

Weight of Evidence for Cancer (PDF) (6 pp, 413 K)

WOE Characterization Framework for WOE Characterization
Not available.
Basis:

Quantitative Estimate of Carcinogenic Risk from Oral Exposure (PDF) (6 pp, 413 K)

Not assessed under the IRIS Program.

Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure (PDF) (6 pp, 413 K)

Not assessed under the IRIS Program.

Organ/System-Specific RfDs

System RfD (mg/m3) Basis PoD UF Confidence Notes
Developmental, Immune 4 x 10-10
(Chronic)
Decreased serum anti-tetanus antibody concentration in children at age 7 yrs (Grandjean et al., 2012; Budtz-Jorgensen and Grandjean, 2018) BMDL (HED): 1.16 x 10-8
mg/kg-day
30 Medium
Endocrine 2 x 10-7
(Chronic)
Decreasedserum total T4 levels in F1 Wistar rats (Ramhoj et al., 2018) NOAEL (HED): 2.45 x 10-5
mg/kg-day
100 Medium
Developmental, Immune 4 x 10-10
(Subchronic)
Decreased serum anti-tetanus antibody concentration in children at age 7 yrs (Grandjean et al., 2012; Budtz-Jorgensen and Grandjean, 2018) BMDL (HED): 1.16 x 10-8
mg/kg-day
30 Medium
Endocrine 2 x 10-7
(Subchronic)
Decreased serum total T4 levels in F1 Wistar rats (Ramhoj et al., 2018) NOAEL (HED): 2.45 x 10-5
mg/kg-day
100 Medium

Chemical Documents

Jan 2025: IRIS Toxicological Review of Perfluorohexanesulfonic Acid (Pfhxs) and Related Salts (Final Report, 2025) (Report)

Nov 2024: IRIS Toxicological Review of Perfluorohexanesulfonic Acid (Pfhxs) and Related Salts (Interagency Science Discussion Draft, 2024) (Report)

Feb 2024: External Peer Review Activities for PFHxS Integrated Risk Information System (IRIS) Assessment (Feb 2024) (Other)

Jul 2023: IRIS Toxicological Review of Perfluorohexanesulfonic Acid (PFHxS) and Related Salts (Public Comment and External Review Draft) (Report)

Jan 2023: IRIS Toxicological Review of Perfluorohexanesulfonic Acid (PFHxS) and Related Salts (Interagency Science Consultation Draft, 2023) (Report)

Nov 2019: Systematic Review Protocol for the Perfluorohexanesulfonic Acid (PFHxS) IRIS Assessment (Preliminary Assessment Materials) (Report)

Other EPA Information

Additional EPA toxicity information may be available by visiting the following sites:
  • Human Health Benchmarks for Pesticides (HHBP). This database provides human health benchmarks for pesticides that may be present in drinking water.
  • Office of Pesticide Programs Pesticide Chemical Search. This database provides links to health effects information and registration status for pesticides.
  • Chemistry Dashboard. This database provides information on chemical structures, experimental and predicted physicochemical, and toxicity data.

Related Links

  • EPA Chemicals Dashboard - Perfluorohexanesulfonic Acid (PFHxS)

Critical Effects

Developmental
Developmental

Endocrine
Endocrine

Immune
Immune

Chemical Structure

Perfluorohexanesulfonic Acid (PFHxS)
  • IRIS Home
  • About IRIS
  • IRIS Recent Additions
  • IRIS Calendar
  • IRIS Assessments
  • Advanced Search
  • IRIS Program Materials
Contact Us to ask a question, provide feedback, or report a problem.
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshots
  • Grants
  • No FEAR Act Data
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data.gov
  • Inspector General
  • Jobs
  • Newsroom
  • Open Government
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions

Follow.