By Dr. Harriet Burge
EMLab P&K Chief Aerobiologist and Director of Scientific Advisory Board
We are often asked if building contents should be discarded as part of mold remediation. The short answer is “NO”. A slightly longer answer is “Not normally” and we are now back into the commonly found gray area of mold remediation.
The goal of mold remediation is to remove active fungal growth and its products from a contaminated space. In most cases this can be done without actually removing the contents of the space. Unfortunately, some investigators are recommending that ALL building contents be removed and discarded.This often results in enormous economic losses that are usually unnecessary. Here are a few guidelines to aid in deciding whether or not something needs to be discarded.
1. Water must be removed, and the problem that allowed the water to be present must be corrected. Otherwise, no amount of mold remediation will solve the problem.
2. Non-porous materials can always be cleaned, even if surface mold growth is present. In these cases, the mold is growing on dust, oil, soap film, or other nutrients attached to the surface of the material. Soap, water, and a little elbow grease will readily remove this kind of contamination. This is common practice when mold grows on shower tiles or in the refrigerator. This principle extends to television sets, metal or plastic furniture, ceramic or vinyl flooring, composition and granite counter tops, etc.
3. Wood can be cleaned unless the fungal growth is rotting the wood. This only occurs when wood has been wet for a long period of time. The blue, green and black powdery molds often seen on wood surfaces are not rotting the wood. As with non-porous materials, the fungi are growing on dust, wax, oils or other nutrients on the wood surface and can be removed with soap and water.
4. Removable soft materials can always be cleaned if the only contamination is from spores released from growth occurring elsewhere. Mattresses can be thoroughly vacuumed and covered in allergen-proof encasings. Upholstered furniture can be professionally cleaned. Drapery can be dry cleaned or washed. Rugs can be professionally cleaned, which involves immersion in soapy water followed by thorough rinsing and rapid drying. Clothing can be washed or dry-cleaned. If the soft material has been wetted and fungi are actually growing on the fibers, then decisions will have to be made about how valuable the object actually is. It is usually worth trying to clean all but the most grossly contaminated materials.
5. Fixed soft materials that have not become wet, and are contaminated only with spores can be cleaned in place either by occupants or professionals. Thorough vacuuming of furniture and installed carpeting is often sufficient. If mold growth within the space has been extensive, professional cleaners can more effectively remove residual spores using high powered suction with rapid drying. If fixed soft materials have become wet and mold has grown within the fibers, then they probably will have to be discarded. This may include gypsum board, wallpaper, and upholstered furniture. Again, good professional cleaning may be sufficient and is certainly worth trying, especially if a material is extremely valuable. Note that people with severe allergies are usually advised not to have upholstered furniture, carpeting or rugs, or draperies that require dry cleaning; and they should always use mattress and pillow encasings.
These cleaning approaches should also remove most of the odors caused by active fungal growth. Residual odors may be caused by undiscovered growth, bacterial growth, or other factors and correctly identifying the source is not always easy. Airing outdoors is the traditional approach to removing residual odors from mattresses, rugs, and clothing. The ultraviolet light and ozone (as well as other chemicals present outdoors) effectively destroy the chemicals that cause these odors. Ozone and ultraviolet use indoors is more problematic. Ozone is routinely used by fire restoration specialists to remove combustion odors. These remediations are always done in unoccupied spaces, and require high ozone concentrations. Obviously, if odors cannot be removed, the object may have to be discarded.
These suggestions are supported by the USEPA in moldguide.pdf and moldremediation.pdf, both available on the EPA website (www.epa.gov). They are also supported by the New York City Guidelines for Mold Remediation.