U.S. TSCA Section 5 Significant New Use Rules (SNUR): Recent Designation Batches and Practical Implications
Overview
Under TSCA Section 5, the U.S. Environmental Protection Agency (EPA) continues to issue Significant New Use Rules (SNURs) designating new uses for new or existing chemical substances. The most recent SNUR designation batches, issued between 2025 and 2026, designate specific multi-walled carbon nanotubes (MWCNTs), novel fluorinated surfactants, and certain aromatic amine compounds, among others. Companies seeking to manufacture, import, process, or use these substances for a SNUR-designated use are required to submit a Significant New Use Notice (SNUN) to EPA at least 90 days before the activity and to obtain EPA's review and clearance (prior approval).
Enforcement Timeline
November 2025: EPA publishes its most recent batch of consolidated SNUR designations (multiple chemicals) in the Federal Register
January 2026: Compliance with this batch begins
As of August 2026: The 90-day advance SNUN filing requirement applies to any new entry into, or change of use for, the designated uses of these chemicals
Business Impact
Companies in the electronics, chemical, and automotive supply chains that supply or locally source new materials—such as nanomaterials or alternative fluorinated compounds—in the United States must carefully review the CAS numbers and designated uses of covered substances (including manufacturing volume limits, worker protection requirements, and aqueous discharge restrictions) and promptly determine whether an SNUN filing is required.