In a notice published in the Federal register on July 28, 2010, the Environmental Protection Agency (EPA) announced that it was adding new information to its public docket EPA-HQ-OPPT-2009-0686 and was reopening the comment period for  a proposed Significant New Use Rule (SNUR) for multiwalled carbon nanotubes (MWCNTS) first published in the Federal Register on February 3, 2010.

The proposed rule requires "persons who intend to manufacture, import, or process the substance" – described elsewhere in the notice as "multi-walled carbon nanotubes(generic)" to "be used as an additive/filler for polymer composites and support media for industrial catalysts" – "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". This would give EPA time to assess "risks that may be presented by the intended uses and, if appropriate, to regulate the proposed use before it occurs."

Information regarding submission of comments will be found in the original notice of February 3, 2010.

The "Significant New Use" for the MWCNTS (generic) are described in the Feb. 3, 2010 notice as

certain changes from the use scenario described in the
PMN could result in increased exposures, thereby constituting a
“significant new use.” EPA has determined that activities proposed as
a “significant new use” satisfy the two requirements stipulated in
Sec.  721.170(c)(2), i.e., these significant new use activities, “(i)
are different from those described in the premanufacture notice for the
substance, including any amendments, deletions, and additions of
activities to the premanufacture notice, and (ii) may be accompanied by
changes in exposure or release levels that are significant in relation
to the health or environmental concerns identified” for the PMN

EPA has determined, however, that use of the substance without the use of gloves and protective clothing, where there is a potential for dermal exposure;
use of the substance without a National Institute for Occupational
Safety and Health (NIOSH)-approved full-face respirator with an N100
cartridge, where there is a potential for inhalation exposure; or use
other than as described in the PMN, may cause serious health effects.
Based on this information, the PMN substance meets the concern criteria
at Sec.  721.170(b)(3)(ii).

Following the closing of the comment period and review of the comments received, EPA will publish summaries and EPA’s replied to the submitted comments in a future issue of the Federal register, along with the final rule.