Toxigenic Mold

The term "toxic mold" is somewhat misleading and has led to misunderstandings and confusion regarding the health-related dangers of mold. In high enough concentrations, all molds -- toxic or otherwise -- may cause health problems. As a result, some sources refer to all mold as "toxic mold."

A few forms of mold are called "toxigenic," meaning that under certain conditions they can produce small molecular toxins, called "mycotoxins." These mycotoxins are usually spread by way of the mold's spores and may be the cause of potentially serious health problems if ingested in sufficient quantities over time.

In contrast with mold in general, which is to be found virtually everywhere, toxigenic molds are less common. Two of the best-known examples of so-called "toxic mold" include:

Stachybotrys chartarum. Sometimes called S. chartarum or Stachybotrys atra, and popularly known as "black mold," this toxigenic mold is a greenish-black fungus that requires a moist environment in which to grow and is most commonly found in flood-damaged buildings. The mycotoxins produced by Stachybotrys chartarum are potent, but there is some evidence that only a few strains of Stachybotrys chartarum are toxigenic, indicating that this particular type of "toxic mold" may be quite rare.

Aspergillis. Aspergillis is a family of molds, and only some Aspergillis molds are toxigenic. The mycotoxins produced by toxigenic strains of Aspergillis are less potent than Stachybotrys chartarum mycotoxins, but infestations of Aspergillis mold are probably far more common. Aspergillis may be found in any of the mold-friendly environments discussed above.

Though some people become ill from these mycotoxins and toxigenic mold, many of the more common health problems thought to be potentially mold-related may be caused by mold that is not strictly speaking toxic (or toxigenic).