On February 27, 2017, the National Institute for Occupational Safety and Health (NIOSH) announced the availability of a draft chapter to be published in the NIOSH Manual of Analytical Methods entitled “Analysis of Carbon Nanotubes and Nanofibers on Mixed Cellulose Ester Filters by Transmission Electron Microscopy” for public comment. The draft chapter provides standardized approaches for the analysis of carbon nanoparticles. NIOSH states that these standardized approaches are intended to harmonize analytical techniques, enabling comparison of results between studies and fostering optimal data quality. According to NIOSH, its scientists published studies on the microanalysis of airborne carbonaceous nanomaterials, and this research led to the procedures described in the chapter. The chapter provides detailed guidance on effective means to perform transmission electron microscopic analysis on carbon nanotubes and nanofibers that are sampled from occupational atmospheres. NIOSH notes that the draft chapter has previously undergone scientific peer review. Comments are due April 28, 2017.