Mold: A Follow-up

Several points of clarification will be helpful to the reader of the Spring 1997 (Volume 29 Issue 1) SGA Newsletter article on mold. The authors offered suggestions for reducing the likelihood of a mold outbreak as well as recommendations for cleaning mold. It cannot be stated too often: a controlled environment in which good air circulation, moderate temperature (68-72 degrees F ) and a relative humidity at an achievable low level (less than 60%, ideally 35-40%) will dramatically aid in preventing large scale outbreaks of mold.

There will be times when mold does appear in collections via incoming materials, a breakdown in the building's envelop or mechanical system, or natural disaster. Because mold is so common in our daily lives (cheese, bread, fruit, bathroom ceilings), we expect there to be an easy, safe, and practical way to deal with an outbreak that we can, in fact, try ourselves at home.

There is no easy way of responding to mold outbreaks on collection materials. Because the metabolism of fungus is much like our own, what is deadly to mold can also be dangerous for us, e.g., ethylene oxide effectively kills mold but is not safe for humans. And because the presence of mold can also be harmful to people, knowledge of and adherence to safety precautions is imperative.

While respiratory protection is generally encouraged in the preservation literature targeting archivists and librarians dealing with mold outbreaks, it is seldom explained. Not everyone is able to wear a respirator. Your physician must determine through a series of simple tests, your medical fitness to wear a negative pressure respirator, as well as provide clearance to work in an environment potentially harmful enough to warrant respirator use. Because wearing a respirator will offer some resistance to breathing, your doctor should be willing to verify in writing that you have no health problems that would preclude your safe use this equipment. The breathing stress created by the use of a respirator is of particular concern to individuals with asthma, a heart condition, or women who are pregnant.

After you have determined your medical fitness, next you must be fit-tested to ensure that the respirator properly fits and is performing its assigned function. Not all respirators fit all faces. Individuals with beards cannot wear half-mask respirators at all. Training is necessary to know how to care for a respirator and when to dispose of the HEPA (high efficiency particulate air) cartridges needed in a mold environment. Training in the use and maintenance of other personal protective equipment, e.g., gloves, coats, is also desirable.

Remove mold ONLY with a vacuum that contains a HEPA filter. Vacuums designed to filter air through water are unsuitable for capturing mold's small particles. Even if a fungicide is present in the water, this will not prevent particles of mold from being exhausted back into the air. Individuals using an aspirating system that involves a flask and a vacuum pump can place a mechanism at the end of the tube (before it reaches the liquid into which debris will be deposited) that forces air through small holes. By reducing the diameter of these holes, the likelihood decreases that particles can be carried through and back out of the system in bubbles (cavitation). Place the vacuum pump in a fume hood to remove particles escaping through the pump's exhaust.

There are some practical steps that can be taken to address a mold outbreak. If the outbreak is limited, isolate items from unaffected materials. Place affected items in a dry paper-based box until treatment. If possible, include a desiccant, such as conditioned silica gel packets. This enclosure will prevent spores from circulating, but will not encourage the growth potentially created by the tightly sealed microclimate of a plastic bag.

If your outbreak is small, and your equipment limited, take your materials outside on a calm mild day and brush them off with a soft white brush, away from you, i.e., downwind. The main impact of direct sun is drying, and this may be useful if materials are damp and the mold is "active." Ultraviolet radiation in daylight is detrimental to paper-based materials and has a minimal effect on mold. It may temporarily inactivate, but will not kill or remove mold. Ultraviolet radiation in a laboratory setting requires appropriate eye and skin protection and is of questionable applicability to paper-based materials.

Do not delay in addressing a mold outbreak. Contact a mycologist when you first become aware of a mold situation. Mold growth is a dynamic process; its appearance today may dramatically differ from its appearance six weeks from now. For additional information, you may contact Robert B. Simmons, Ph.D., Biological Imaging Facility, Department of Biology, Georgia State University 404-651-3138 biorbs@panther.gsu.edu