On October 31, 2022, the U.S. Environmental Protection Agency (EPA) proposed 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. 87 Fed. Reg. 65548. The proposed 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).

According to EPA, the PMNs state that the use of the substances will be as electrically conductive materials; heat dissipation materials; heat generation materials; additives for weight reduction; additives to improve physical or mechanical properties; additives in batteries, energy storage, and electrode applications; and additives in field emission applications. According to the notice, based on analogy to asbestos fibers and data for other MWCNTs, EPA identified concerns for lung effects (lung overload and lung carcinogenicity) if poorly soluble, respirable particulates and fibers are inhaled. Based on comparison to analogous chemical substances, EPA identified concerns for eye irritation and systemic effects. Based on the presence of cobalt oxide as a residual at 2.1%, EPA identified concerns for the P-20-64 chemical substance for acute neurotoxicity, dermal and respiratory sensitization, mutagenicity, and carcinogenicity. EPA states that it was unable to estimate the environmental hazard of these new chemical substances. EPA issued the Order under TSCA Sections 5(a)(3)(B)(ii)(I) and 5(e)(1)(A)(ii)(I), based on a finding that in the absence of sufficient information to permit a reasoned evaluation, the substances may present an unreasonable risk of injury to human health or the environment. To protect against these risks, the Order requires:

• No domestic manufacture (e., import only);

• No 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;

• Use of personal protective equipment where there is a potential for dermal exposure;

• Use of a National Institute for Occupational Safety and Health (NIOSH)-certified respirator with an assigned protection factor (APF) of at least 50 where there is a potential for inhalation exposure;

• No manufacture of the PMN substances with a maximum weight percent of cobalt oxide impurity in exceedance of 2.1%;

• Process and use of the PMN substances only as electrically conductive materials; heat dissipation materials; heat generation materials; additives for weight reduction; additives to improve physical or mechanical properties; additives in batteries, energy storage, and electrode applications; or as additives in field emission applications;

• Establishment of a hazard communication program, including human health precautionary statements on each label and on the safety data sheet (SDS); and

• No release of the PMN substances, or any waste stream containing the PMN substances, into water.

The proposed SNURs would designate as a “significant new use” the absence of these protective measures.

EPA states that it determined that certain information may be potentially useful in support of a request by the PMN submitter to modify the Order, or if a manufacturer or processor is considering submitting a significant new use notice (SNUN) for a significant new use that will be designated by this SNUR. EPA determined that the results of specific target organ toxicity, carcinogenicity, eye irritation, and aquatic toxicity testing may be potentially useful to characterize the human health and environmental effects of the PMN substances. Although the Order does not require these tests, the Order’s restrictions remain in effect until the Order is modified or revoked by EPA based on submission of this or other relevant information. Comments are due November 30, 2022.