One aspect of the response to a biological attack using anthrax spores sent through the mail has been to use electron irradiation to treat the mail. This irradiation procedure has altered the materials and objects in ways that were probably not anticipated. The mail was damaged by both thermal and radiation processes. Business, government, and personal records are all sent through the mail and damage to these records must be assessed for archival reasons. The irradiated paper became discolored and lost its ductility, i.e. became brittle, and components of some ballpoint pen inks were chemically altered. Thermal effects caused the sticking together of pages in books and journals. Photographic images, slides, and negatives were damaged and often destroyed. Objects such as computer disks were also damaged by melting or softening of their plastic components.