> >Regardless of shelf life, a practical consideration is whether or not a researcher would use the old chemical if fresh was available.

This also plays into the cost of storing chemicals; lab space is much more valuable when it is used to use chemicals than it is to store them. And probably the biggest cost associated with a library of chemicals in storage is paying for the human resources of a librarian to keep track of what is available in storage and what needs to be restocked...

- Ralph

Ralph Stuart, CIH, CCHO
Chemical Hygiene Officer
Keene State College

ralph.stuart**At_Symbol_Here**keene.edu