On October 27, 2016, the U.S. Environmental Protection Agency (EPA) proposed significant new use rules (SNUR) for three chemical substances that were the subject of premanufacture notices (PMN), including functionalized carbon nanotubes (generic). According to the notice, the PMN states that the substance will be used as a thin film for electronic device applications. Based on structure-activity relationship (SAR) analysis of test data on analogous carbon nanotubes and other respirable poorly soluble particulates, EPA identified potential lung effects and skin penetration and toxicity induction from inhalation and dermal exposure to the PMN substance. Further, EPA predicts toxicity to aquatic organisms via releases of the PMN substance to surface water. EPA states that it does not expect significant occupational exposures due to the use of impervious gloves, and because the PMN is used in a liquid and is not spray applied except in a closed system. EPA does not expect environmental releases during the use identified in the PMN. Therefore, EPA has not determined that the proposed manufacturing, processing, and/or use of the substance may present an unreasonable risk to human health or the environment. EPA states that it has determined, however, that any use of the substance without the use of impervious gloves, where there is potential for dermal exposure; manufacturing the PMN substance for use other than as a thin film for electronic device applications; manufacturing, processing, or using the PMN substance in a form other than a liquid; use of the PMN substance involving an application method that generates a mist, vapor, or aerosol except in a closed system; or any release of the PMN substance into surface waters or disposal other than by landfill or incineration may cause serious health effects or significant adverse environmental effects. Based on this information, according to EPA, the PMN substance meets the concern criteria at 40 C.F.R. Section 721.170(b)(3)(ii) and (b)(4)(ii). EPA determined that the following tests would help characterize the health and environmental effects of the PMN substance:
- The results of a fish early-life stage toxicity test (OPPTS Test Guideline 850.1400);
- A daphnid chronic toxicity test (OPPTS Test Guideline 850.1300);
- An algal toxicity test (OCSPP Test Guideline 850.4500);
- A 90-day inhalation toxicity test (OPPTS 870.3465) with additional testing parameters beyond those noted at 40 C.F.R. Section 870.3465, for using the 90-day subchronic protocol for nanomaterial assessment;
- A two-year inhalation bioassay (OPPTS Test Guideline 870.4200); and
- A surface charge by electrophoresis (for example, using ASTM E2865-12 or NCL Method PCC-2 — Measuring the Zeta Potential of Nanoparticles).
EPA promulgated final SNURs on May 16, 2016, for these three chemical substances. EPA received notices of intent to submit adverse comments, however, and withdrew the direct final SNURs on July 14, 2016. EPA notes that the applicable review periods for the PMNs submitted for the three chemical substances all ended prior to June 22, 2016, the date on which President Obama signed into law the Frank R. Lautenberg Chemical Safety for the 21st Century Act, which amends the Toxic Substances Control Act (TSCA). Comments on the proposed SNURs are due November 28, 2016.