Health hazard evaluation report: HETA-2005-0291-3025, University of Dayton Research Institute, Dayton, Ohio.
Methner-MM; Birch-ME; Evans-D; Hoover-MD
Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, HETA 2005-0291-3025, 2006 Oct; :1-20
On July 8, 2005, the National Institute for Occupational Safety and Health (NIOSH) received a management request to conduct a health hazard evaluation (HHE) at the University of Dayton Research Institute (UDRI) in Dayton, Ohio. The request asked NIOSH to evaluate potential sources of emissions from carbon nanofiber handling processes. No health complaints were reported by management or workers. Measurements made with real-time instruments capable of sizing and determining airborne particle concentrations indicate that most processes did not release substantial quantities of carbon nanofibers when compared to background particle measurements. However, some processes (wet sawing of composite material and the transferring of carbon nanofibers to a mixing vessel) did elevate area airborne particle mass concentrations. Surface sampling indicated that carbon nanofiber material migrated from the laboratory to an adjacent office area, with employee footwear being the most likely means of transport. Despite the absence of occupational exposure criteria, UDRI management decided to take a cautious approach and instituted a policy requiring the use of personal protective equipment (PPE). The PPE used by lab workers included disposable Tyvek lab coats, latex gloves, and elastomeric half-mask respirators with a P100 pre-filter and organic vapor cartridge. A laboratory hood and local exhaust ventilation were evaluated with "smoke tubes" and appeared to operate as designed. NIOSH investigators cannot conclude whether a health hazard exists to UDRI laboratory workers from exposure to nano-scale materials. There are currently no occupational exposure limits for carbon nanofibers nor clearly defined health effects, so no conclusions can be made regarding excessive exposure. The UDRI lab did have exhaust ventilation available to control potential releases of carbon nanofibers, but the ventilation was not operating during mixing outside the laboratory hood or wet saw cutting. The lab workers were wearing PPE; however, latex gloves should be replaced with nitrile gloves to avoid the potential development of latex allergy.
Region-5; Dusts; Dust-particles; Dust-exposure; Dust-control; Particulates; Particulate-dust; Ventilation; Ventilation-systems; Personal-protective-equipment; Protective-equipment; Respiratory-protective-equipment; Materials-handling; Nanotechnology;
Author Keywords: Research and Development in the Physical, Engineering, and Life Sciences; nanotechnology; nanoparticles; carbon nanofibers; composites; polymers; exposure assessment; particle concentration; nanomaterial handling practices; fugitive emissions
Field Studies; Hazard Evaluation and Technical Assistance
NTIS Accession No.
Research Tools and Approaches: Control Technology and Personal Protective Equipment
National Institute for Occupational Safety and Health