Creating a Mold Preventive Environment

Reprinted in part from “The Invasion of the Giant Mold Spore”

SOLINET Preservation Services Leaflet

By Sandra Nyberg, November 1987

Revised 2003

Mold and mildew can have an adverse effect on people. Those with allergies, asthma or other respiratory problems should stay away from infested areas, as many fungi will seriously irritate and inflame lungs. Some fungi can cause skin and eye irritation and infections. Prolonged exposure to germinating molds in closed areas (which exist in many library collections) can damage the lungs, mucous membrane, cornea, respiratory tract, stomach, intestines, and skin. Some varieties of mold are highly toxic.

People predisposed to upper respiratory problems such as allergies and asthma should not be exposed to areas affected with mold, even if they wear a respirator. For health reasons, even a small mold outbreak should be taken seriously. You should wear disposable rubber or plastic gloves, a lab coat and a respirator whenever handling moldy materials. Ordinary dust masks are not sensitive enough to filter mold spores, use a respirator with a HEPA (high efficiency particulate arrestant) filter. Be aware that respirators are ineffective if used improperly; for example, people with facial hair will not be protected because they can’t get a tight fit. Wash protective clothing in hot water and bleach.

What can you do to prevent a mold outbreak?

The ONLY way to permanently protect your collections from mold is to control the environment by keeping the temperature within 65°-70° Fahrenheit and the relative humidity within 45%-65%. Prevention is the key but if you do experience a mold outbreak there are non-chemical means for clean-up and recovery. Some chemicals kill mold, but the only safe and effective way to keep it from coming back is to modify the environment which contributed to the development of mold. Some of the chemicals used in the past by libraries to kill mold are no longer recommended, because many are harmful to both people and collections.

For patron comfort, temperatures of 70° Fahrenheit plus or minus 2° are acceptable in libraries, provided relative humidity is kept at 50%. In conjunction with humidity and temperature control, adequate air circulation will help prevent mold growth. Air circulation helps control moisture levels through evaporation.

• Don't shelve books directly against an outside wall. Due to temperature and humidity differences between inside and outside environments, moisture may develop along walls. Allowing air to circulate against the walls will enable the moisture to evaporate.
• Keep the quantity of indoor plants to a minimum and don't allow indoor planted areas.
• Waterproof basements and walls below ground level. And use water-sealant paint on floors and walls.
• Place or adjust outside gutters and drains so that water does not collect near the outside walls. Check gutters and drains regularly to avoid clogs. Place lawn sprinkler systems so that they do not soak outside walls.
• Regularly inspect your collection for mold or mildew. This will allow you to catch any infestation before it becomes large. And continue to monitor potentially hazardous areas until the environment can be stabilized in an appropriate state.

What can you do if you have a mold outbreak?

There are a number of things you can do when faced with mold in your collection, but first you need to determine what has caused the mold to grow. Check the humidity and temperature. Chances are good that, for a large infestation, the cause at least partially lies there. Also look for a source of water, such as an unnoticed leak, a broken window, or moisture along outside walls. A third place to check is the heat-exchange coils in the heating/air conditioning system; they are a prime area for fungus growth and spore distribution. They can be cleaned using a commercial EPA registered cleaning solution, one such solution is Purolator 180 (antimicrobial HVAC treatment). You need to pinpoint whatever caused the mold to develop and then fix it, because until you solve that problem, mold will continue to grow, no matter how often you treat the affected material.

Your second response should be to isolate affected materials. If a small quantity of books is moldy, seal them in air-tight plastic bags. If the infestation is large, quarantine the area. You should wear rubber or plastic gloves and a dust or filtration mask whenever handling moldy materials. Isolating moldy books and papers serves two purposes: it minimizes the spread of mold, and it protects those persons who may have allergies or respiratory problems from harm.

Third, do what you can to increase air circulation and lower humidity. Open windows, provided it is not raining outside and the relative humidity outside is lower than that inside. Set up fans to increase air circulation. Set up dehumidifiers or readjust the HVAC system to lower the relative humidity. If you have a thermostat-controlled cooling system or one which simply lowers the temperature of outside air prior to ventilating it through the building, turn it off. This kind of "air conditioning" or cooling system does not provide humidity control and will in fact increase internal relative humidity because cold air cannot hold as much water as warm air. Furthermore, the moist heat-exchange coils in this system may be providing a fertile ground for the growth of mold, the spores of which are then distributed throughout the building via its ventilation system.

What other things can be done to deal with an outbreak, or to help prevent future ones?

Most authorities agree that fumigating collections with toxic chemicals is rarely necessary for dealing with mold and mildew problems. Storing collections in appropriate environmental conditions should prevent the need for fumigation. To quote Dr. Thomas Parker, of Pest Control Services, Inc.:

“Fumigation will not control mold and mildew if the library materials are placed back into the same conditions from which they came. In most instances library materials that have been fumigated are then stored in areas which do not have an environment conducive to mold growth. The success of the fumigation is given as a reason for the control of the mold and mildew, when in fact, the new area in which the materials are stored is the governing factor as to why mold and mildew is now being controlled.”

Maintenance of proper environmental conditions will prevent mold growth. And if mold does occur, a relatively gentle form of cleaning along with improving the environment will solve the problem in most situations. I recommend that you try the following instead of chemical treatments.

• Determine the Cause: Check temperature and relative humidity levels; check to see if the material has been wet and, if so, why; check heat-exchange coils in air conditioning units.
  
• Isolate Material: Place individual items in sealed plastic bags; quarantine stacks; for large and heavy infestations, it may be necessary to restrict access to the building/room. Don’t leave materials in plastic bags for extended periods of time; follow up with cleaning as soon as possible.
  
• Modify the Environment: Readjust relative humidity to the best of the HVAC system’s ability; set up fans to keep air circulating in the affected area; install portable dehumidifiers in the affected area if the HVAC system cannot be controlled; turn lights on in affected areas for as long as possible during periods of obvious mold growth. Continuously record temperature and relative humidity until they stabilize at an acceptable level.
  
• Clean: Vacuum with a HEPA vacuum then wipe books or papers with a clean dry rag or a soft brush (wearing proper protective apparel); clean shelves, walls, floors, air conditioning heat-exchange coils, air vents, etc. with Lysol, Clorox, X-14, or other mold-killing solutions; if you are dealing with a small quantity of books you can set them out in the sun to dry out, otherwise use fans following the ethanol/vacuum cleaning.
  
• Remove Odors: Charcoal and/or baking soda can be used to remove the odor of mold, if the treatment has not done so. Simply place briquettes and/or bowls of baking soda in the area to absorb the odor. Do not wipe the books or paper with the charcoal or baking soda.
  
• Monitor: Keep watch on the affected area for several months beyond the mold outbreak and clean-up, even after the environment has been restored to conditions which inhibit mold growth.

Research and testing continue to assess the effectiveness of fungicides, to determine appropriate treatment procedures, and to identify molds and mildews and their characteristics. Studies might result in changes to existing procedures for mold control in the future. The SOLINET Preservation Program is able to provide advice and assistance in dealing with mold infestations in specific situations. Please call if we can help.

soliNET Southeastern Library Network Inc.
1438 West Peachtree Street NW • Suite 200 • Atlanta, GA 30309-2955 | 1.800.999.8558 toll free • 404.892.7879 fax