Here are two NIOSH reports on the handling of powders.  If you search the NIOSH page for powders you will find other reports.

http://www.cdc.gov/niosh/docs/2012-147/pdfs/2012-147.pdf

http://www.cdc.gov/niosh/docket/archive/pdfs/NIOSH-245/0245-082611-Topmiller_pres.pdf

Hoods are recommended.

-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Ralph B Stuart
Sent: Tuesday, June 26, 2012 9:42 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: [DCHAS-L] Toxic dust handling

A question has arisen here about the best practices for handling dusts known to be unusually toxic, such as teratogens or mutagens. It appears from google searches that many academic Standard Operating Procedures recommend using these dusts in a fume hood. This seems counter-intuitive to me, as strong air flows around these dusts would seem to create a housekeeping challenge by dispersing the dust around the use area. This could lead to unnecessary contamination of someone's hands as they work with the material. In addition, the ergonomics of performing delicate operations, such as handling dusts, in a hood can be a challenge due to their one size fits all nature.

Prudent Practices indicates that highly toxic dusts should be used in a hood, but that seems to be rolled up in the same recommendation as for handling gases and vapors. It seems to me that dusts present distinct hygiene challenges from gases and vapors. I wonder if anyone has addressed this issue with specific rules that distinguish between these kinds of chemicals?

Thanks for any information about this.

- Ralph

Ralph Stuart CIH

Laboratory Ventilation Specialist

Department of Environmental Health and Safety Cornell University

rstuart**At_Symbol_Here**cornell.edu