Moldy Claims - Conclusion
Conclusion
Infections by molds and other fungi are rarely significant causes of disease in humans. Superficial fungal infections of the skin and nails are relatively common in normal individuals, but those infections can be treated effectively and they generally resolved without complications. The fungi which cause superficial infections are not the type which grow on building materials. Only a small number of fungi, Blastomyces, Coccidioides, Cryptococcus, and Histoplasma, cause serious disease in individuals who have normally functioning immune systems. Fortunately, those fungi do not grow in indoor environments, but their spores may come indoors with outdoor air if there is a source near open windows or building air intakes. Individuals who have severely impaired immune systems are at significantly increased risk of serious fungal infections. However, fungi are so common and ever-present that avoidance of fungi is very difficult even in the confines of hospital isolation units.
Some of the molds that can grow indoors are capable of producing toxic substances, mycotoxins, under appropriate conditions of growth. Adverse health effects caused by molds and mycotoxins have been recognized for centuries when contaminated foods have been eaten. Occupational diseases are also well known in association with inhalation of high levels of fungi, bacteria, and other organic matter in industrial and agricultural settings. However, despite a great number of studies spanning two decades, there is no proven association between indoor mold exposure and various nonspecific health complaints.
The mold Stachybotrys chartarum has come to cause particular fear when it is found indoors. However, the studies that stimulated that fearful response have been disavowed by the CDC, and no similar studies have been published by others. Despite the fact that it can produce toxic substances under appropriate growth conditions, years of intensive study have failed to establish exposure to Stachybotrys in home, school, or office environments as a cause of adverse human health effects. Actual levels of exposure in indoor environments, dose-response data in animals, and dose-rate considerations all make it highly unlikely that a toxic dose of mycotoxins can be delivered by inhalation of indoor air.
Mold spores are present in all indoor environments and cannot be eliminated from them. Normal building materials and furnishings can support the growth of many species of molds, but only if there is an adequate supply of moisture. Where mold grows indoors there is an inappropriate source of water. Mold growth should be reduced to the extent practicable in the home, school or office, since it physically destroys the building materials on which it grows; it is unsightly and may produce offensive odors; and it is likely to sensitize and produce allergic responses in those who are susceptible.
Nevertheless, except for persons with severely impaired immune systems, indoor mold is not a source of fungal infections, and current scientific evidence does not support the idea that human health has been adversely affected by inhaled mold toxins in home, school, or office environments. Thus, the notion that “toxic mold” is an insidious, secret “killer,” as so many media reports and trial lawyers would claim, is “junk science” unsupported by actual scientific study.
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