US EPA

This Independent Peer Review Draft document presents a case study of multiwalled carbon nanotubes (MWCNTs); it focuses on the specific example of MWCNTs as used in flame-retardant coatings applied to upholstery textiles. This case study is organized around the comprehensive environmental assessment (CEA) framework, which structures available information pertaining to the product life cycle, environmental transport and fate, exposure-dose in receptors (i.e., humans, ecological populations, and the environment), and potential impacts in these receptors. The document does not draw conclusions about potential risks, or present an exhaustive review of the literature. Rather, it was used in an independent peer review to provide feedback on revisions that EPA made to the external review draft of the document based on public comments and the CEA process to identify research gaps for MWCNTs.

Engineered nanoscale materials (nanomaterials) are generally described as having at least one dimension between 1 and 100 nanometers (nm). Due to their small size, nanomaterials often have novel properties that confer different potential benefits and risk compared to their non-nano form. The assessment of such risks and benefits requires information, but given the nascent state of nanotechnology, much remains to be learned about the characteristics and effects of nanomaterials. The external review draft of this case study provided a starting point for a workshop process that engaged experts with diverse technical backgrounds (e.g., toxicology, polymer science, environmental fate and transport) and sector perspectives (e.g., industry, academia, government). Information on a historically used flame-retardant (decabromodiphenyl ether, or decaBDE) was included in the draft case study document as a more robust dataset to help experts identify potential key data gaps in assessing risks from MWCNTs. Experts used the external review draft of the case study document to identify and prioritize research gaps that could support future assessment and risk management efforts for MWCNTs. This prioritization took place through a structured decision process that allowed each expert to have equal input on the outcome. RTI International, an EPA contractor, independently conducted this structured workshop process through the use of web-based tools and a face-to-face workshop.

Subsequently, EPA revised the draft case study document to highlight the priority research areas identified through the structured workshop process, as well as incorporate valuable feedback from public commenters and experts participating in the RTI workshop process. These revisions included streamlining the document by highlighting how decaBDE information could inform MWCNT research planning and moving details on decaBDE to an appendix. The revised case study (i.e., peer review draft) then underwent an independent letter peer review. A final case study that reflects revisions EPA made in response to peer review comments is now available (see “Related Links” below).

This document seeks to identify what is known and unknown related to assessing the health and environmental implications of a nanomaterial; in this case multiwalled carbon nanotubes (MWCNTs) used in flame-retardant coatings applied to textiles.

EPA released the final case study document (see “Related Links” below).

U.S. EPA. Nanomaterial Case Study: A Comparison of Multiwalled Carbon Nanotube and Decabromodiphenyl Ether Flame-Retardant Coatings Applied to Upholstery Textiles (Independent Peer Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-12/043B, 2013.