New Recommendations Released for Occupational Exposure to Ultrafine TiO2
July 1, 2011
WASHINGTON, DC – The National Institute for Occupational Safety and Health (NIOSH) has released a new Current Intelligence Bulletin (CIB) that addresses exposure limits to ultrafine titanium dioxide. Titanium dioxide is produced and used in the workplace in varying particle-size fractions, including fine and ultrafine sizes.
The NIOSH CIB reviews the animal and human data relevant to assessing the carcinogenicity and other adverse health effects of TiO2, provides a quantitative risk assessment using dose-response information from the rat and human lung dosimetry modeling, and recommends occupational exposure limits for fine and ultrafine (including engineered nanoscale) TiO2. Additionally, it describes exposure monitoring techniques, exposure control strategies and research needs. It only addresses occupational exposures by inhalation and not nonoccupational exposures.
According to the report, “NIOSH recommends exposure limits of 2.4 mg/m3 for fine TiO2 and 0.3 mg/m3 for ultrafine (including engineered nanoscale) TiO2, as time-weighted average (TWA) concentrations for up to 10 hours per day during a 40-hour work week. NIOSH has determined that ultrafine TiO2 is a potential occupational carcinogen but that there are insufficient data at this time to classify fine TiO2 as a potential occupational carcinogen. However, as a precautionary step, NIOSH used all of the animal tumor response data when conducting dose-response modeling and determining separate RELs for ultrafine and fine TiO2. These recommendations represent levels that over a working lifetime are estimated to reduce risks of lung cancer to below 1 in 1,000. NIOSH realizes that knowledge about the health effects of nanomaterials is an evolving area of science. Therefore, NIOSH intends to continue dialogue with the scientific community and will consider any comments about nano-size titanium dioxide for future updates of this document.”
For the full report, visit http://www.cdc.gov/niosh/docs/2011-160/pdfs/2011-160.pdf.