Impurity (PFAS Context)

In the context of TSCA Section 8(a)(7), an impurity is a PFAS substance that is unintentionally present in a chemical substance, mixture, or article as a result of manufacturing processes, raw material contamination, or environmental exposure. The November 2025 proposed revision to the PFAS Reporting Rule would exempt PFAS present as unintentional impurities from reporting requirements. This recognizes that many manufacturers have no knowledge of or control over trace PFAS contamination in incoming materials.

40 CFR § 705.3; EPA November 2025 Proposed Rule (90 FR 50923); TSCA §3.

The impurity exemption is one of six proposed exemptions in the November 2025 revision. It directly addresses industry concerns that the original rule’s lack of a de minimis threshold would require companies to report trace PFAS contamination they did not intentionally introduce and may not be able to detect without expensive analytical testing. Companies should still conduct reasonable due diligence on incoming materials to understand potential PFAS impurity sources.

A cosmetics manufacturer sources a glycol solvent that, through upstream fluorochemical manufacturing processes, contains 15 ppm of a PFAS impurity. Under the original TSCA 8(a)(7) rule, the cosmetics company might need to report. Under the proposed impurity exemption, this unintentional contamination would be exempt.