The U.S. Environmental Protection Agency published on October 19, 2017, a direct final rule promulgating significant new use rules (SNUR) for 29 chemical substances that were the subject of premanufacture notices (PMN). The 29 chemical substances are subject to consent orders issued by EPA under Section 5(e) of the Toxic Substances Control Act. The direct final rule includes a SNUR for multi-walled carbon nanotubes (MWCNT) (generic) (PMN Numbers P-15-487, P-15-488, P-15-489, P-15-490, and P-15-491). According to the Federal Register notice, the PMN substances will be used as additives for electro-static discharge in electronic devices, electronics, and materials; additives for weight reduction in materials; additives to improve mechanical properties or electrical conductivities; heat-generating elements in heating devices and materials; additives for heat transfer and thermal emissions in electronic devices and materials; semi-conductor, conductive, or resistive elements in electronic circuitry and devices; additives to improve conductivity in electronic circuitry, energy storage systems, and devices; electron emitters for lighting and x-ray sources; additives for electromagnetic interface shielding in electronic devices; additives for electrodes in electronic materials and electronic devices; catalyst support in chemical manufacturing; coating additives to improve corrosion resistance or conductive properties; additives for fibers in structural and electrical applications; additives for fibers in fabrics and textiles; filter additives to remove nanoscale materials; semi-conducting compounding additives far high-voltage cable; and additives for super-hydrophobicity. The consent order requires:
- Use of personal protective equipment to prevent dermal exposure and a National Institute for Occupational Safety and Health-certified respirator with N-100, P-100, or R-100 cartridges with an assigned protection factor of at least 50 (where there is a potential for inhalation exposure);
- Use of the PMN substances only for the uses specified in the consent order;
- No use in application methods that generate a dust, mist, or aerosol unless such application method occurs in an enclosed process; and
- No use of the PMN substances resulting in releases to surface waters and disposal of the PMN substances only by landfill or incineration.
A significant new use is any use involving an application method that generates a dust, mist, or aerosol. The SNUR requirements do not apply when the PMN substances have been incorporated into a polymer matrix that has been reacted (cured) or embedded in a permanent solid polymer form that is not intended to undergo further processing except mechanical processing. EPA states that it determined that a subchronic 90-day inhalation toxicity study (OPPTS 870.3465 or OECD 413), a two-year inhalation bioassay (OPPTS 870.4200), a fish early-life stage toxicity test (OCSPP Test Guideline 850.1400), a daphnid chronic toxicity test (OCSPP Test Guideline 850.1300), and an algal toxicity test (OCSPP Test Guideline 850.4500) would help characterize possible health and environmental effects of the substances. Although the consent order does not require these tests, EPA notes that the order’s restrictions on manufacture, processing, distribution in commerce, and disposal will remain in effect until the order is modified or revoked by EPA based on submission of this or other relevant information.