Books are prone to dampness if the relative humidity is not maintained below 60%. Prolonged damp conditions results to mold growth on the paper and on the bindings. Mold growth on books leads to damage of books through staining and or breaking down of paper and other book components. Besides the damage, many molds isolated from books are a health hazard capable of causing serious respiratory diseases and allergies of various degrees. Molds commonly isolated from moldy books include species of Aspergillus, Penicillium, Cladosporium, Trichoderma, Chaetomium, Stachybotrys, Epicoccum and a number of others. Trichoderma, Chaetomium, and Stachybotrys are strong producers of the enzyme cellulase that breaks down the paper.

Procedure for cleaning moldy books

If the books are not extensively damaged (i.e, the paper is still intact), they can be saved. Below is a brief procedure that can be used to clean moldy books.

• Workers must wear appropriate personal protective equipment when handling contaminated books. This includes wearing coverall or other protective coat over street clothing, a respirator (i.e. N95 or better) and vinyl examination gloves. Unprotected individuals risk aggravating or developing allergic sensitivities to the mold spores.
• Cleaning must be conducted within a temporary containment unit away from air intakes, other building openings and public areas.
• Moldy books must be HEPA vacuumed on the following areas: outside front and back covers, joints between the covers, spine, text block and inside back and front covers. A soft-bristled brush may be used to remove stubborn mold growth. (NB: Care must be taken not to damage the books).
• Once cleaning of books is completed, book carts that were holding moldy books must be cleaned with disinfectant and paper towels. Refer to the material safety data sheets (MSDS) of the disinfectants before use.
• Before re-shelving, the cleaned books must be given a quick wipe down with an appropriate disinfectant solution, the floors and shelf areas must be cleaned and disinfected and the shelves and flooring must be cleaned with disinfectant and paper towels.
• After completing the cleaning, the exterior of the HEPA vacuum cleaner is wiped down with a disinfectant to kill any settled spores.
• Workers must remove protective coveralls, eye protection, respirator, and gloves outside and wash hands with soap and hot water after completing the cleaning session.
• A record of where the problem areas are, the cause of the problem, a list of the cleaned books, the time and day when the cleaning took place must be kept for future reference.
• Implement a preventative cleaning program to address the continuing mold problem in the library.