The National Institute for Occupational Safety and Health has released a draft Current Intelligence Bulletin – Health Effects of Occupational Exposure to Silver Nanomaterials for public comment. NIOSH will hold a public meeting in Cincinnati, Ohio on March 23, 2016, and will receive written public comments on the draft through April 22, 2016 (an extension of the original public comment deadline).
NIOSH issues Current Intelligence Bulletins (CIBs) to share new scientific information about occupational hazards with representatives of academia, industry, organized labor, public health agencies, and public interest groups, as well as to federal agencies responsible for ensuring the safety and health of workers. In recent years, NIOSH has been paying particular attention to occupational hazards relating to nanoscale materials. In 2013, NIOSH released a CIB relating to carbon nanotubes (Current Intelligence Bulletin 65) and addressed nanoscale titanium dioxide in its 2011 Current Intelligence Bulletin 63 – Occupational Exposures to Titanium Dioxide.
Silver nanomaterials are used in diverse applications including antibacterials and electronics. The draft Current Intelligence Bulletin (CIB) reviews and assesses current scientific information about toxicological effects of exposure to silver nanomaterials in animals and cells and occupational exposures to silver dust and fumes. It makes recommendations for the safe handling of silver nanoparticles.
The NIOSH current Recommended Exposure Limit (REL) for silver is 10 micrograms per cubic meter (8-hour time-weighted average) for silver metal dust and soluble compounds. Significantly, NIOSH concludes that there is insufficient information to develop an REL for silver that is specific to particle size. NIOSH therefore recommends that “effective risk control practices be implemented so that worker exposures to silver nanomaterials do not exceed” the current REL, which would include fumes as well.
NIOSH’s proposed recommendations for safe handling of silver nanoparticles include:
- Employers to conduct comprehensive exposures assessments;
- Employers to substitute less hazardous materials;
- Employers to establish, select, install and evaluate engineering controls;
- Employers to require workers to wear protective clothing and gloves made of non-woven materials;
- Employers to routinely evaluate airborne exposures; and
- Employers to develop procedures for accidental spills.