US EPA

EPA has finalized the IRIS Toxicological Review of Perfluorobutanoic Acid (PFBA) and Related Salts This assessment addresses the potential cancer and noncancer human health effects from exposure to perfluorobutanoic acid and related salts. EPA’s program and regional offices may use this assessment to inform decisions to protect human health.

U.S. EPA. IRIS Toxicological Review of Perfluorobutanoic Acid (PFBA) and Related Salts (Final Report, 2022). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-22/277F, 2021.

Perfluorobutanoic Acid (PFBA, CASRN 375-224) and its related salt (ammonium perfluorobutanoic acid [NH4+PFBA], CASRN 10495-86-0) are members of the group of per and polyfluoroalkyl substances (PFAS). Concerns about PFBA 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.

PFBA 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. PFBA 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 PFBA-containing products.

Date	Description
01-Nov 2019	EPA released the Systematic Review Protocol for the PFAS IRIS Assessments (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 2020	EPA sent an interagency science consultation PFBA draft for review and comment.
04-Aug 2021	EPA released the draft IRIS Toxicological Review of Perfluorobutanoic Acid (PFBA) and Related Compound Ammonium Perfluorobutanoic Acid for a 60-day public comment period and external peer review. Additionally, EPA announced the solicitation for the nominations of members to a PFAS IRIS Review Panel that will review all five assessments. [Federal Register Notice Aug 23, 2021]
05-Oct 2021	EPA extended the public comment period until November 8, 2021. EPA additionally updated the draft and supplemental information documents and included an erratum to clarify that the assessment addresses the PFBA free acid as well as simple salts of PFBA. [Federal Register Notice Oct 20, 2021]
06-Feb 2022	ERG, a contractor to EPA, hosted an independent public peer review meeting from February 22-23, 2022, to discuss the review of the IRIS assessment of PFBA and related salts.
07-Jun 2022	ERG, a contractor to EPA, submitted their final peer review report to EPA on the review of the IRIS assessment of PFBA and related salts (see downloads).
08-Nov 2022	EPA submitted the revised interagency science discussion draft for final Agency and Interagency review.
09-Dec 2022	EPA posted the final report IRIS Toxicological Review of Perfluorobutanoic Acid (PFBA) and Related Salts (final Report) and released the interagency science discussion draft comments to the IRIS database.

The Perfluorobutanoic Acid (PFBA) IRIS assessment was released for a 60-day public comment period. Following the external peer review meeting, the assessment will be revised taking into consideration all public and external peer review comments received.

This document has been reviewed in accordance with U.S. Environmental Protection Agency policy and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

• IRIS Toxicological Review of Perfluorobutanoic Acid (PFBA) and Related Salts (PDF)  (145 pp, 3 MB, about PDF)
• IRIS Toxicological Review of Perfluorobutanoic Acid (PFBA) and Related Salts - Supplemental Materials (PDF)  (138 pp, 2 MB, about PDF)
• IRIS Toxicological Review of Perfluorobutanoic Acid (PFBA) and Related Salts - Executive Summary (PDF)  (6 pp, 372 KB, about PDF)
• Errata Sheet (May 2023) (PDF)  (1 pp, 72 KB, about PDF)

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• Systematic Review Protocol for the PFAS IRIS Assessments (2021)
• IRIS Toxicological Review of Perfluorobutanoic Acid (PFBA) and Related Salts (Public Comment and External Review Draft, 2021)
• External Peer Review Activities for PFBA Integrated Risk Information System (IRIS) Assessment (Nov 2021)
• IRIS Toxicological Review of Perfluorobutanoic Acid (PFBA) and Related Salts (Interagency Science Discussion Draft Comments, 2022)