Construction Industry Trends
October 2004
The Toxic Mold Debate
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There are more than 10,000 species of mold in the world, and nearly 1,000 of them have been found in U.S. homes. Yet when most people think of mold these days, only one type comes to mind — "toxic mold." While toxic mold is not technically a scientific term, over the past few years, certain species of mold have been purported to cause a variety of health problems — thereby earning themselves the label.
Toxic mold most often refers to a mold called Stachybotrys chartarum, a greenish-black mold that grows on material such as fiberboard, gypsum board, and paper. Like many other molds, it produces spores that, when inhaled, can cause allergy-like symptoms. But Stachybotrys received its more nefarious name due to the belief that it can cause much more significant and perhaps even permanent physical damage, and may even be the cause of sick-building syndrome.
While consumer advocates have entered the toxic mold debate citing anecdotal evidence of the effects of Stachybotrys on occupants of homes and commercial buildings infested with the mold, the insurance industry has fought back. It claims the toxic mold phenomenon is a result of media hysteria and that there is little scientific evidence to back it up. The Insurance Information Institute, in its white paper Mold and Insurance, cites findings by the Centers for Disease Control (CDC), quoting the agency as reporting that “there are very few case reports that toxic molds (those containing certain mycotoxins) inside homes can cause unique or rare health conditions such as pulmonary hemorrhage or memory loss. These case reports are rare, and a causal link between the presence of the toxic mold and these conditions has not been proven.”
Whether or not the evidence bears out the true toxicity of Stachybotrys still remains to be seen. Even so, despite all its press, Stachybotrys is far from being the only mold that building owners must deal with. According to the CDC, the most commonly found molds in indoor environments are Cladosporium, Penicillium, Aspergillus, and Alternaria.
Still, Stachybotrys continues to have an impact on the public imagination. It has spurred new legislation, including California’s Toxic Mold Protection Act of 2001. In this case, the name is somewhat misleading — the Act actually refers to all types of mold, and not just Stachybotrys. In part, the Act tasks the California Department of Health Services with the job of adopting permissible exposure limits for mold — all types of mold — in indoor environments.
Another piece of legislation named after toxic mold is House Resolution 1268, also known as the Melina Bill or the United States Toxic Mold Safety and Protection Act of 2003. While it has not yet been voted on, the bill again refers for the most part to all molds, rather than just toxic mold. It is designed to create federally recognized standards for preventing, detecting, and remediating indoor mold growth; to regulate disclosure of mold in homes offered for sale or lease; and to offer tax credits to tax payers for non-reimbursed mold inspection and remediation work. In fact, only two sections of the bill specifically refer to toxic mold.
Despite all the debate, in the end, mold is mold, says Holli Merchant, principal industrial hygienist, MACTEC. “Somebody will call me up and says, ‘I have black mold,’” she says, referring to the toxic mold hype. “But really, it could be two or three different kinds of mold. And I don’t care what type of mold it is. I only care about why it’s there (which usually is the result of too much water or moisture in a building) and more impotantly, how we can mitigate it.”