Byproduct (PFAS Reporting Context)

In the context of TSCA Section 8(a)(7), a byproduct is a chemical substance produced without a separate commercial intent during the manufacture, processing, use, or disposal of another chemical substance or mixture. PFAS byproducts can form during manufacturing processes (e.g., fluoropolymer production) or during thermal decomposition of PFAS-containing materials. Under the original October 2023 rule, byproducts were reportable; the November 2025 proposed revision would exempt PFAS manufactured as byproducts from reporting.

TSCA § 3(2)(A); 40 CFR § 705.3; EPA November 2025 Proposed Rule (90 FR 50923).

The byproduct exemption, if finalized, would remove a significant reporting burden. Many manufacturers generate trace PFAS byproducts unintentionally during production. Under the current rule, these companies must identify, quantify, and report those byproducts. Tracking byproducts is technically challenging because they may exist at trace concentrations and require advanced analytical methods to detect. Companies should prepare for either outcome by identifying potential PFAS byproduct formation pathways in their processes.

A fluoropolymer manufacturer producing PTFE may generate trace amounts of PFOA as a byproduct during polymerization. Under the original TSCA 8(a)(7) rule, the manufacturer would need to report these byproduct quantities. If the proposed exemption is adopted, this byproduct would be excluded from reporting.