Perfluorobutane sulfonic acid (1-Butanesulfonic acid, nonafluoro-) [PFBS]: federal lists and state cleanup levels

Federal lists

Toxic chemicals for release reporting (TRI)

• 40 CFR 372.65(d)
• Revised as of July 1, 2025

40 CFR 372.65(d), the per- and polyfluoroalkyl substances among the toxic chemicals subject to release reporting, lists CAS 375-73-5 with an effective date for reporting of 1/1/22.

Table 4 to Paragraph (d): (d) Per- and polyfluoroalkyl substances alphabetical listing.

Chemical name	CASRN1	Effective date
Perfluorobutane sulfonic acid	375-73-5	1/1/22

Notes to Table 4 to Paragraph (d): (d) Per- and polyfluoroalkyl substances alphabetical listing., as the regulation prints them

¹ CASRN means Chemical Abstracts Service Registry Number.

Pennsylvania

• PA DEP
• Act 2 Statewide Health Standards
• PFAS groundwater table updated 7/10/2024

For PERFLUOROBUTANE SULFONIC ACID (PFBS), DEP's PFAS groundwater table prints 2 µg/L for residential groundwater in a used aquifer with TDS up to 2500, and its Statewide Health Standard tables print 66 mg/kg for residential soil direct contact from 0 to 15 feet.

• 2µg/L R DEP's PFAS groundwater table Used Aquifers, TDS ≤ 2500
• 66mg/kg 0-15 feet Table 3a: Medium-Specific Concentrations (MSCs) for Organic Regulated Substances in Soil: A. Direct Contact Numeric Values Residential

All Pennsylvania values for PERFLUOROBUTANE SULFONIC ACID (PFBS)

Texas

• TCEQ
• TRRP Tier 1 PCLs
• February 6, 2025

For Perfluorobutane sulfonic acid (1-Butanesulfonic acid, nonafluoro-) [PFBS], TCEQ's Tier 1 table prints 86 mg/kg for TotSoilComb and 0.11 mg/kg for GWSoilIng (residential soil, 0.5 acre source area), and 0.034 mg/L for GWGWIng (residential groundwater).

• 86mg/kg 8.6E+01 TotSoilComb Table 1: Tier 1 Residential Soil PCLs 0.5 acre source area
• 0.11mg/kg 1.1E-01 GWSoilIng Table 1: Tier 1 Residential Soil PCLs 0.5 acre source area
• 0.034mg/L 3.4E-02 GWGWIng Table 3: Tier 1 Groundwater PCLs - Residential and Commercial/Industrial Residential

All Texas values for Perfluorobutane sulfonic acid (1-Butanesulfonic acid, nonafluoro-) [PFBS]

For the federal lists the regulation governs. This page copies the Code of Federal Regulations' annual edition revised as of July 1, 2025, which is kept up to date by the Federal Register; amendments published there since that date are not shown. This page is a reference copy and not a reporting decision. Check the current regulation before relying on a value.

A list with no section on this page has no row with this CAS number. That alone does not put the substance outside the list: the lists also have entries with no CAS number (broad classes, chemical categories, waste streams), which a page filed by CAS number cannot show.

Each agency's own publication governs: its current table, or the published rule where the agency says so. This page is a reference copy and not a cleanup decision. Check each agency's page before relying on a value.

Source

• Environmental Protection Agency, 40 CFR parts 302, 355 and 372, in Title 40 of the Code of Federal Regulations, Parts 300 to 399, revised as of July 1, 2025, as the U.S. Government Publishing Office posts it. File read October 6, 2026.
• Pennsylvania Department of Environmental Protection, Statewide Health Standard Medium-Specific Concentrations.
• PFAS groundwater table: DEP's file dated July 24, 2024, read October 5, 2026.
• Table 3a: DEP's file dated January 4, 2022, read October 5, 2026.
• Table 3b: DEP's file dated January 19, 2022, read October 5, 2026.
• Texas Commission on Environmental Quality, Texas Risk Reduction Program Tier 1 Protective Concentration Levels, last revised February 6, 2025. File read October 1, 2026.