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workers, building, architect

NORA Manufacturing Sector Strategic Goals

927ZHNB - Current Intelligence Bulletin: Carbon Nanotubes

Start Date: 10/1/2008
End Date: 10/30/2013

Principal Investigator (PI)
Name: Faye Rice
Phone: 513-533-8335
Organization: NIOSH
Sub-Unit: EID
Funded By: NIOSH

Primary Goal Addressed

Secondary Goals Addressed
6.0, 9.0

Attributed to Manufacturing


Project Description

Short Summary

The project purpose is to develop a NIOSH CIB to convey the potential health risks from exposure to single-walled and multiwalled carbon nanotubes and carbon nanofibers. Relevant health effects data will be presented along with interim risk management recommendations. The CIB and other NIOSH products such as web pages and presentations will communicate and disseminate the most current research results and recommendations on the health and safety issues involved in carbon nanotube and carbon nanofiber technology.

This project contributes to the goals of the NIOSH Nanotechnology Cross-Sector Program.

The major output will be a NIOSH policy document (i.e., C IB) on occupational exposure to CNTs and carbon nanofibers.

Intermediate outcomes may include interim recommendations, development of key stakeholder partnerships, presentations, peer -reviewed journal articles, and NIOSH educational materials that will provide information on potential health hazards, proposed recommended exposure limits, control measures, and guidance on personal protective equipment.


Current toxicologic research suggests that inhalation of engineered carbon nanotubes and carbon nanofibers may have the potential to cause cancer and fibrosis in occupational settings. To assess these risks and inform workers, NIOSH will develop a policy document (i.e., Current Intelligence Bulletin) to summarize the state of knowledge of the adverse health effects of engineered carbon nanotubes and carbon nanofibers. The NIOSH document will include health recommendations to protect workers based on a quantitative risk assessment using toxicologic dose-response data.

-Initiate document development: FY09
-Conduct risk assessment using toxicologic data from animal studies: FY10.
-Complete NIOSH Nanotechnology Review Center (NTRC) review of draft CIB: April 2010
-Post external review draft on NIOSH website: August 2010

Mission Relevance

Nanotechnology is a rapidly expanding technology with great potential impact on the global economy. The technology involves creating or engineering materials in the nanometer size range. Particles and materials in this size range exhibit new and often unique properties with the potential to improve the performance of many existing products. Carbon nanotubes (CNT) and carbon nanofibers are carbon-based nanomaterials developed and produced in quantities ranging from research scale to commercial production and in some instances, carbon nanotubes are being introduced into existing processes and products. The market for CNTs is estimated to grow to over 8 billion dollars in the next decade. Results from recent in vitro and in vivo studies with singlewalled and multi-walled carbon nanotubes have demonstrated their ability to be cytotoxic when tested in various cell cultures and to cause an acute inflammatory response followed by an early onset of lung fibrosis when delivered to the lungs of mice by pharyngeal aspiration or inhalation. Exposures to single-walled and multi-walled carbon nanotubes (SWCNT and MWCNT) were more potent than either ultrafine carbon black or crystalline silica and of similar potency to chrysotile asbestos [Lam et al. 2004; Shvedova et al. 2005; Muller et al. 2005; Ryman-Rasmussen et al. 2009b]. There is also some evidence indicating that some types of well-dispersed MWCNT can move through the outer wall of the lung and into the intrapleural space in mice following exposure by pharyngeal aspiration and when administered intraperitoneally to mice, MWCNT cause asbestos-like pathogenicity.

While a causal link for disease from exposure to SWCNT and MWCNT has not been definitively established, concern about a possible cancer hazard has prompted additional research, in addition to investigating a possible fibrosis/nonmalignant respiratory disease hazard.

Worker exposures to SWCNT and MWCNT are of special concern because of their small size and fiber-like dimensions. No studies have reported on the health effects in workers producing or using CNT. However, since humans can also develop lung inflammation and fibrosis in response to inhaled particles and fibers, it is reasonable to assume that at equivalent exposures, workers would also be at risk of developing these adverse lung effects.

CNT are currently used in numerous applications, including electronics, lithium-ion batteries, solar cells, super capacitors, reinforced plastics, micro-fabrication conjugated polymer activators, biosensors, enhanced electron-scanning microscopy imaging techniques, and in pharmaceutical/biomedical devices for bone grafting, tissue repair, drug delivery, and medical diagnostics.

CNT are encountered in facilities ranging from research laboratories and CNT production plants to operations where CNT are processed, used, disposed, or recycled. The extent of worker exposure to CNT has not yet been quantified.

The body of public/occupational health literature and NIOSH Nanotechnology Research Center (NTRC) worksite surveys relating to CNT and carbon nanofibers will be obtained and assessed for potential use in the draft document. Data from animal toxicologic studies will be used to assess the potential health risk to workers exposed to CNT over a working lifetime.

The NIOSH project will develop and produce a policy document (i.e., CIB) and other educational materials that will provide information on potential health hazards, recommended exposure limits, control measures, and guidance on personal protective equipment. The purpose of the NIOSH CIB is to convey the potential occupational health risks from exposure to single-walled and multi-walled carbon nanotubes and carbon nanofibers and NIOSH risk management recommendations.