thoriated tungsten

[Scott Davidson <Scott.Davidson@EM.DOE.GOV>]

     thoriated tungsten is exempt from NRC licensing requirements under 10 
     CFR 40 if the wt% is less than 4%
     
     Question:  If a welder is using this material, is his exposure to the 
     fumes regulated under Part 20? What if the use of the material is at a 
     licensed facility?