All, Apparently a student was using a thiol based chemical which has an extremely low odor threshold. Trace amount of the agent were on wipes which were disposed of in a general waste container. Even this small quantity elicited an extremely strong odor throughout the cleanroom resulting in the evacuation of the cleanroom. In the future please read the MSDS over carefully before using any new material and if material lists an odor please see me for detailed handling procedures before use of the material. Stephen Jurss Safety Manager