I have read many varying opinions on the necessary levels of disposal/cleaning needed for potentially mold contaminated surfaces and items (i.e. clothing, furniture, drapery, etc.). If you have moldy drywall at a finished basement or bedroom with no other signs of impacted materials, when do you stop needing to discard items or having to have items cleaned?  What about clothing?  If in a closet with mold at carpeting/drywall, what steps are appropriate for clothing that does not show signs of infestation?  Finally, what about furniture in a moldy basement that does not show signs of mold contamination?-Benjamin - Pennsylvania

            I can empathize with you.  I have seen a number of remediation protocols that require intensive cleaning of ordinary items such as hard and soft furniture, books, drapes, electronic equipment, photos – everything that one finds in a house – as it were contaminated with mercury, radioactive isotopes, or some similar toxic/hazardous material.  In many of these circumstances toxic mold species have not even been identified as present. 

            The issue of toxic mold aside, mold spores are how fungal organisms of decay are transported from one substrate to another.  As such, mold spores can be found on most surfaces including those indoors through the natural course of dissemination.  When one opens windows particularly during the fall of the year mold spores are carried in and deposited on surfaces (much as the pollen in spring). These spores become a part of the many particles that compose the dust in our buildings.  As dust is disturbed and re-suspended, we are exposed to whatever is in the dust over and over again until the dust is somehow removed and organic particles such as mold spores undergo biological decomposition.  Because of natural sources outdoors as well as any even minor sources indoors, it is virtually impossible to remove all mold spores from building furnishings and materials. 

            In the case of toxic mold such as Stachybotrys, the likelihood of significant contamination of building materials is quite small.  Carpeting and soft furniture are the exceptions.  Carpeting is difficult to clean, soft furniture less so.  It is often easier to take up carpeting and replace it than to have it cleaned to the satisfaction of those responsible for developing remediation protocols, and of course clients. 

            Most cleaning protocols are based on uncertainty, the uncertainty as to what constitutes a health risk, the uncertainty as to what the liability risk is for mold remediation protocol writers if the nth degree of cleaning is not provided, the uncertainty of clients of what the health risks are to them even if one spore of a toxic mold remains.  It is this uncertainty that results in cleaning/disposal recommendations that in many cases are extreme and extraordinarily expensive. 

            For most mold remediations disposal should be limited to infested materials and in some cases carpeting. Cleaning can be limited to vacuuming soft surface materials and wet wiping hard surfaces. Many “mold experts” recommend HEPA vacuuming because they assume it provides the greatest degree of cleaning. There is no evidence to support this assumption. HEPA vacuuming works best on very small particles like asbestos. Mold spores are much larger. In many cases it is the suction potential of the cleaner that is likely to be the main factor in how well materials are cleaned rather than the small particle collection efficiency of a vacuuming system. Clothing can be cleaned by washing or dry cleaning.  There is no reason to clean clothing stored in closed structures (such as drawers)where air movement is limited. 

            There will always be some residual mold spores on interior building surfaces following a remediation.  The best way of controlling exposure to residual mold spores is to install a multi-pleated filter module on the return air duct (upstream of the blower fan) and operate it 12-24 hours a day for several months.  This will reduce building dust levels and mold spore levels along with it.  In many cases it may be a low cost alternative to the cleaning recommendations prescribed in remediation protocols.  

October 9, 2003

 Indoor Environmental Quality (2000), Thad Godish Ph.D., C.I.H

Direct E-mail 00tjgodish@bsu.edu