US EPA

In February 2022, the draft IRIS Assessment of Perfluorohexanoic Acid (PFHxA) and Related Salts (Public Comment and External Review Draft) and the draft charge to external peer reviewers were released for a 60-day public review and comment period. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House Offices before public release. Consistent with the May 2009 IRIS assessment development process, all written comments on IRIS assessments submitted by other federal agencies and White House Offices are made publicly available. Accordingly, interagency comments and the interagency science consultation materials provided to other agencies, including interagency review drafts of the Toxicological Review and the charge to external peer reviewers, are posted on this site.

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.

EPA is undertaking an update of the Integrated Risk Information System (IRIS) health assessment for PFHxA and it's related salts. The outcome of this project is an IRIS Toxicological Review and Executive Summary for PFHxA that will be entered into the IRIS database.

The Perfluorohexanoic Acid (PFHxA) and Related Salts IRIS assessment was released for public comment in Jan 2022. Following the public comment period, there will be an external peer review. The assessment will then be revised taking into consideration public and peer review comments.

U.S. EPA. IRIS Toxicological Review of Perfluorohexanoic Acid (PFHxA) and Related Salts (Interagency Science Consultation Draft, 2021). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-20-326, 2021.