The document recommends an occupational exposure limit and measures for controlling work-related exposures to those types of nanomaterials, based on the current state of knowledge. It also suggests areas where further research is vital for more certainty in assessing potential risk of adverse health effects for workers in the manufacture and industrial use of carbon nanotubes and carbon nanofibers.
“As nanotechnology becomes more widely used and as public awareness grows, employers, workers, and health and safety professionals all increasingly seek guidance on measures for controlling occupational exposures,” said NIOSH Director John Howard, M.D. “These diverse stakeholders agree that the prudent stewardship of nanotechnology is essential for public acceptance and U.S. competitiveness in the global market.
“Meeting this need poses a tremendous challenge for scientists,” Dr. Howard noted. “As we continue the research necessary for understanding the unique properties and implications of nanomaterials, we are also tasked by the fact that nanomaterials are already being produced and used in the workplace, where workers may be exposed to them. This is particularly true of carbon nanotubes and carbon nanofibers, which are currently used in numerous industrial and biochemical applications. We invite public comment on the draft Current Intelligence Bulletin to help us develop final recommendations.”
The draft document includes:
- A recommendation that employers minimize work-related exposures until scientific studies can fully clarify the physical and chemical properties of carbon nanotubes and carbon nanofibers that define their potential for adverse occupational health effects through inhalation. It recommends a strategic approach for assessing potential work-related exposures and risks, controlling exposures through a hierarchy of measures, instituting appropriate medical screening programs and educating workers on sources and job tasks that may expose them to these types of nanomaterials.
- A recommended exposure limit (REL) of 7 micrograms of carbon nanotubes or carbon nanofibers per cubic meter of air as an 8-hour, time-weighted average, respirable mass concentration. This is the concentration that most can reliably be measured with current instrumentation. The draft document states, “NIOSH recognizes that the REL may not be completely health protective but its use should help lower the risk of developing [work-related] lung disease and assist employers in establishing an occupational health surveillance program that includes elements of hazard and medical surveillance.” It recommends that airborne concentrations should be reduced as low as possible below the REL by making optimal use of sampling and analysis.
The draft document is available at http://www.cdc.gov/niosh/docket/review/docket161A/ for written public comment until Feb. 18, 2011. NIOSH will hold a public meeting to discuss and obtain comments on Feb. 3, 2011, in Cincinnati, Ohio.
NIOSH has worked with its partners to advance strategic research on the occupational health and safety aspects of nanotechnology for more than 6 years and has published numerous studies, recommendations and scientific methods in this pioneering area. For more information, visit http://www.cdc.gov/niosh/nanotech.