As expected, in the February 3, 2010, Federal Register, the Environmental Protection Agency (EPA) published a proposed Significant New Use Rule (SNUR) under the Toxic Substances Control Act for multi-walled carbon nanotubes. In the summer of 2009, EPA published a similar rule under a more expeditious approval process but that proposed rule was withdrawn after EPA received notice of a challenge to the rule. At the time of withdrawal, EPA forecasted that it would be publishing a SNUR with full opportunity for notice and comment. In EPA's summary of the proposed SNUR, EPA states, "This action would require persons who intend to manufacture, import, or process the substance for an activity that is designated as a significant new use by this proposed rule to notify EPA at least 90 days before commencing that activity. The required notification would provide EPA with the opportunity to evaluate the intended use and, if necessary, to prohibit or limit that activity before it occurs." Comments on the proposed rule are due by March 5, 2010.
The chemical substance that is the subject of this rule applies to NAICS codes 325 and 324110. However, EPA acknowledges that this listing is not exhaustive and the rule may apply to other manufacturers, importers and processors of this material. The carbon nanotube that is the subject of this SNUR is the material described in a Premanufacturing Notice (PMN) P-08-199. To clarify past confusion about the applicability of the SNURs that EPA has proposed for single-walled and multi-walled carbon nanotubes, EPA states in the proposed rule that, "In the past, some stakeholders have asked whether these types of SNURs apply to all variants of carbon nanotubes. This is not the case." The material described in the PMN for P-08-199 is used as an additive/filler for polymer composites and support media for industrial catalysts.
EPA believes that test data on analogous respirable, poorly soluble particulates and on other carbon nanotubes suggests that these multi-walled nanotubes create concerns for lung effects, immunotoxicity and mutagenicity from exposure. For uses described in the PMN, inhalation and dermal exposures are minimal when adequate personal protective equipment is used. Thus, EPA has determined that the material does not pose an unreasonable risk when used in such a manner. The SNUR sets forth specifics on which protective equipment should be used.
In addition, EPA recommends certain testing on the multi-walled material to "help characterize the human health effects of the PMN substance." The testing, however, is not mandatory as a condition of use but it might facilitate EPA's review of a proposed use during its 90-day review period. EPA cautions that persons should contact the agency before performing any of the recommended tests.
While this proposed SNUR applies only to the material that is the subject of P-08-199, the processes described in this rule and the tests that are recommended could form a baseline for future rules affecting single-walled and other multi-walled carbon nanotube products.