Factors that you should consider when weighing solids include:

• Toxicity, permissible exposure limit (PEL), short term exposure limit (STEL), lethal dose 50%, (LD50), carcinogenicity, etc.
  
• Solid particle size: large crystals or fine powder that could easily become airborne
  
• Volume to be weighed g vs. kg portions (exposure time)
  

For example, we would move a top loading balance to a hood for weighing all materials that contain cyanide or hexavalent chromium. For larger quantities we would put a larger scale in a transfer hood. I would also put a label on the container stating that this compound should be only weighed in the hood. Preferably, when possible weigh the compound directly into the beaker that it will be used and add water if you are making an aqueous solution before removing it from the hood. This will prevent making dust during a secondary transfer to another container.

Best regards,

Allen Jones

Electroplating/HES

arjones999**At_Symbol_Here**gmail.com

www.linkedin.com/in/arjones999