We are in the process of changing the nitrogen tank that supplies the BNC, and as a result will be releasing a very large quantity of liquid nitrogen. Think of this as "outdoor air conditioning!" The result will be the formation of a large white cloud coming from the building. This is not hazardous; it is just the result of very cold air being released into the atmosphere. John John R. Weaver Facility Manager Birck Nanotechnology Center Purdue University (765) 494-5494 jrweaver@purdue.edu