What the mail must go through

From Boston, Mass., at a meeting of the American Chemical Society

After last fall’s anthrax attacks, the postal service began irradiating government mail.

The result: yellowed envelopes, shrunken address windows, and brittle paper. Even worse, the sterilization process destroyed some important objects and documents.

Charles Tumosa and his coworkers at the Smithsonian Center for Materials Research and Education in Suitland, Md.,