Two New OARS-WEELs Open for Public Comment

Published April 16, 2014

Toxicology Excellence for Risk Assessment (TERA) is now accepting public comments on OARS-WEELs for the chemicals 2,4-Dinitranisole (DNAN) and 3-Nitro-1,2,4-Triazol-5-One (NTO).

According to TERA, DNAN is being investigated as a replacement for 2,4,6-Trinitrotoluene (TNT) in melt-cast insensitive munitions (IM) formulations. The chemical is also used industrially in the synthesis of dyes and insect repellants. The recommended WEEL value for DNAN is 0.1 mg/m3 (0.01 ppm) as an 8-hour time-weighted average.

TERA notes that NTO was developed as a potential replacement for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and other energetics in military munitions. NTO is also a component of IMX-101, which is an insensitive munition designed to prevent unplanned explosions. The recommended WEEL value for NTO is 2 mg/m3 as an 8-hour time-weighted average.

Comments are due by Friday, May 23. More information on the comment process, including PDFs of the WEELs, is available on TERA’s website.

The AIHA Guideline Foundation's Workplace Environmental Exposure Levels® (WEELs) development process was transferred to TERA under the Occupational Alliance for Risk Science (OARS) initiative in July 2013. WEELs are airborne concentration limits that provide guidance for protecting most workers from adverse health effects related to occupational chemical exposures. The table of WEEL values is available on TERA’s website and on