The Toxic Substances Control Act (TSCA) provides USEPA with authority to require reporting, record-keeping, and testing requirements and to place restrictions on chemical substances and/or mixtures. With respect to nanomaterials such as carbon nanotubes (CNTs), USEPA has previously stated it would deem nanoscale versions of substances listed on the TSCA Inventory to be “existing” chemical substances. Therefore, such substances would not be required to meet TSCA’s pre-manufacturing notification requirements for “new” – i.e., not on the TSCA Inventory – chemical substances. However, USEPA has since revised its approach, expressing concern that nanomaterials may have different features from their non-nanoscale counterparts. Accordingly, USEPA is pursuing a comprehensive regulatory scheme under TSCA to ensure that nanomaterials are manufactured and used in a manner that protects against unreasonable risks to human health and the environment. This regulatory approach includes requiring for nanomaterials (1) pre-manufacturing notifications (PMNs), (2) Significant New Use Rules (SNURs), (3) information submissions, and (4) testing requirements for certain nanomaterials already in commerce.

In line with this regulatory scheme, USEPA last month issued a final rule circulating SNURs for several new chemical substances subject to PMNs, including carbon nanotubes. The text of the rule specifically addresses multi-walled carbon nanotubes (MWCNTs) registered on the TSCA Inventory as PMN P-12-44. The rule applies to persons who manufacture, import, process, or use MWCNTs and requires them to notify USEPA at least 90 days before commencing any of these activities.

Based upon available information on similar substances, USEPA justifies including MWCNTs under the rule because of possible lung effects to workers exposed to CNTs . As MWNCTs are described in the PMN, no significant inhalation exposures are expected to workers due to the manufacturing, processing, and uses described in the PMN and the use of adequate personal protective equipment; but USEPA expects that some fraction of CNTs, if released into the environment, will eventually be suspended in water. Sublethal effects – including respiratory stress, ventilation rate, gill mucus secretion, gill damage, and aggressive behavior – have been observed in fish levels as low as 100 parts per billion.

The last date for comments on the rule was June 10, 2013. The rule is set to become effective July 8, 2013.