US EPA

In February 2022, the IRIS Program released the draft IRIS Toxicological Review of Perfluorohexanoic Acid (PFHxA) and Related Salts for public comment and external peer review. The IRIS assessment of PFHxA will undergo an independent external scientific peer review managed by ERG, a contractor to EPA. Additional information about the peer review meeting is listed with the downloads below and located on the external peer review meeting site.

U.S. EPA. IRIS Toxicological Review of Perfluorohexanoic Acid (Pfhxa) and Related Salts (Public Comment and External Review Draft, 2022). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-21/312, 2022.

Perfluorohexanoic Acid (PFHxA) and its related salts are members of the group of per and polyfluoroalkyl substances (PFAS). Concerns about PFHxA and other PFAS stem from the resistance of these compounds to hydrolysis, photolysis, and biodegradation, which leads to their persistence in the environment. PFAS are not naturally occurring in the environment; they are man-made compounds that have been used widely over the past several decades in consumer products and industrial applications because of their resistance to heat, oil, stains, grease, and water.

PFHxA is a breakdown product of other PFAS that are used in stain-resistant fabrics, paper food packaging, and carpets; it is also used for manufacturing photographic film, and it is used as a substitute for longer chain perfluoroalkyl carboxylic acids (PFCAs) in consumer products. PFHxA has been found to accumulate in agricultural crops and has been detected in household dust, soils, food products, and surface, ground, and drinking water.

As such, exposure is possible via inhalation of indoor or outdoor air, ingestion of drinking water and food, and dermal contact with PFHxA-containing products.

Date	Description
01-Nov 2019	EPA released the Systematic Review Protocol for the PFAS IRIS Assessment (Preliminary Assessment Materials). [Federal Register Notice Nov 8, 2019]
02-Jul 2020	EPA released an update to the Systematic Review Protocol for the PFBA, PFHxA, PFHxS, PFNA, and PFDA IRIS Assessments in response to public comments.
03-Aug 2021	EPA sent an interagency science consultation PFHxA draft for review and comment.
04-Feb 2022	EPA released the draft IRIS Toxicological Review of Perfluorohexanoic Acid (PFHxA) and Related Salts for a 60-day public comment period and external peer review. EPA also released the interagency science consultation documents, comments from reviewers, and EPA's response to major comments. [Federal Register Notice: Feb 2, 2022 ]
05-Aug 2022	EPA posted the final peer review report from the contractor on the EPA website.

The toxicological review of PFHxA and related salts was released for a 60-day public comment period and external peer review. Following the external peer review meeting, the assessment will be revised, taking into consideration all public and external peer review comments received.

If you have a disability and the format of any material on our web pages interferes with your ability to access the information, please contact Dahnish Shams (shams.dahnish@epa.gov) AND hotline.iris@epa.gov. To enable us to respond in a manner most helpful to you, please indicate the nature of the accessibility problem, the web address of the requested material, your preferred format in which you want to receive the material (electronic format (ASCII, etc.), standard print, large print, etc.), and your contact information.

This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.

• IRIS Toxicological Review of Perfluorohexanoic Acid (PFHXA) and Related Salts (Public Comment and External Review Draft, Feb 2022) (PDF)  (196 pp, 4 MB, about PDF)
• IRIS Toxicological Review of Perfluorohexanoic Acid (PFHXA) and Related Salts (Public Comment and External Review Draft, Feb 2022) Supplemental Information (PDF)  (63 pp, 1 MB, about PDF)
• Draft External Peer Review Charge Questions for the IRIS Toxicological Review of Perfluorohexanoic Acid and Related Salts (PDF)  (5 pp, 192 KB, about PDF)
• External Panel Peer Review of EPA's Draft IRIS Toxicological Review of Perfluorohexanoic Acid (PFHXA) and Related Salts (Final Peer Review Report) (PDF)  (155 pp, 2 MB, about PDF)

If you have a disability and the format of any material on our web pages interferes with your ability to access the information, please reach out to us using the Contact us about IRIS form for assistance. To enable us to respond in a manner most helpful to you, please indicate the nature of the accessibility problem, the web address of the requested material, your preferred format in which you want to receive the material (electronic format (ASCII, etc.), standard print, large print, etc.), and your contact information.

• IRIS Toxicological Review of Formaldehyde-Inhalation (External Review Draft, 2022)
• Systematic Review Protocol for the PFAS IRIS Assessments (2021)
• Systematic Review Protocol for the Perfluorohexanoic Acid (PFHXA) IRIS Assessment (Preliminary Assessment Materials, 2019)
• External Peer Review Activities for PFHXA Integrated Risk Information System (IRIS) Assessment (Feb 2022)

• Primary Literature Search References Sorted By Author (PFHXA)

• FR Notice: Feb 2, 2022

Comments on the assessment may be submitted and reviewed using the Docket ID EPA-HQ-ORD-2021-0561