On December 18, 2023, the U.S. Environmental Protection Agency (EPA) issued final significant new use rules (SNUR) under the Toxic Substances Control Act (TSCA) for a number of chemical substances that were the subject of premanufacture notices (PMN) and are also subject to Orders issued by EPA pursuant to TSCA. 88 Fed. Reg. 87346. The SNURs include four chemical substances identified as:

• Multi-walled carbon nanotubes (MWCNT); closed; 4.4-12.8 nanometer (nm) diameter; bundle length 10.6-211.1 micrometer (µm); Grade: Jenotube 6 (PMN P-20-62);

• MWCNTs; closed; 5.1-11.6 nm diameter; bundle length 1.9-552.0 µm; Grade: Jenotube 8 (PMN P-20-63);

• MWCNTs; closed; 7.9-14.2 nm diameter; bundle length 9.4-106.4 µm; Grade: Jenotube 10 (PMN P-20-64); and

• MWCNTs; closed; 17.0-34.7 nm diameter; globular shape; Grade: Jenotube 20 (PMN P-20-65).

Significant new uses include manufacturing the substance with a maximum weight percentage of cobalt oxide impurity in excess of 2.1 percent and processing or using the substance other than as an electrically conductive material, a heat dissipation material, a heat generation material, an additive for weight reduction, an additive to improve physical or mechanical properties, an additive in batteries, energy storage, and electrode applications, or an additive in field emission applications. Although the SNURs state that significant new uses also include to “process or use the substance in application methods that do not generate a vapor, mist, dust, or aerosol unless such an application method occurs in an enclosed process,” this is presumably an error. The proposed SNURs, issued on October 31, 2022, included “[n]o processing or use of the PMN substances in an application method that generates a vapor, mist, dust, or aerosol unless such application method occurs in an enclosed process” as a significant new use. 87 Fed. Reg. 65548. The final SNURs will be effective February 16, 2024. After that date, persons who intend to manufacture (including import) or process any of these MWCNTs for an activity that is designated as a significant new use by the SNURs must notify EPA at least 90 days before commencing that activity.

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