Exposures during wet production and use processes of nanomaterials: a summaryof 11 worksite evaluations

摘要

From 2011–2015, the National Institute for Occupational Safety and Health NanotechnologyField Studies Team conducted 11 evaluations at worksites that either produced engineerednanomaterials (ENMs) via a wet process or used ENMs in a wetted, suspended, or slurryform. Wet handling or processing of ENMs reduces potential exposure compared to dryhandling or processing; however, air sampling data indicated exposures may still occur.Information was gathered about each company, production processes, ENMs of interest, andcontrol measures. Exposure assessments included air sampling using filter media, surfacewipe sampling, and real-time particle counting by direct-reading instruments. Electronmicroscopy analysis of air filters confirmed the presence of ENMs of interest (10 of 11sites). When a method was available, chemical analysis of filters was also used to detectthe presence of ENMs (nine of 11 sites). Wipe samples were collected at four of the 11sites, and, in each case, confirmed the presence of ENMs on surfaces. Direct-reading datashowed potential nanomaterial emissions (nine of 11 sites). Engineering controls includedfume hoods, cleanrooms, and enclosed processes. Personal protective equipment was requiredduring all 11 evaluations. Recommendations to address potential exposures were provided toeach company following the hierarchy of controls.