The Truth About "Toxic" Mold

Concern about toxic mold is increasing with heightened public awareness that exposure can cause serious health problems- and even death. However, all molds, toxic or not, should be of concern when they persist at elevated levels indoors.

Mold affects both the home and workplace environment, compromising the structural integrity of buildings and the health of those inside.

Recent claim settlements have reached high into the millions-the most notorious case being a $32 million settlement in Austin, Texas, which was later reduced to a $4 million verdict.

The heath effects associated with mold vary depending on the type of mold and the person exposed. Immuno-altered and immuno-compromised individuals (i.e. infants, elderly, and those with pre-existing conditions) are at a much higher risk of suffering health effects. Exposure to mold, via skin contact, ingestion, or inhalation, can result in allergic reactions, infections, or toxic (poisonous) effects. The associated symptoms range from a rash and cold and flu-like effects to neurological damage and even death.

Molds are found almost everywhere; they can grow on virtually any organic substance, as long as moisture and oxygen are present. In buildings, molds grow on wood, paper, carpet, foods, and insulation. When excessive moisture accumulates in buildings or on building materials, mold growth will often occur, particularly if the moisture remains undiscovered or unaddressed. It is impossible to eliminate all mold and mold spores in the indoor environment. Indoor mold growth is manageable, however, by controlling moisture.

In some cases, indoor mold growth may not be obvious. Mold can grow on hidden surfaces, such as the backside of dry wall, wallpaper, or paneling, the top of ceiling tiles, the underside of carpets and pads, etc. Some building materials, such as vinyl wallpaper may act as a vapor barrier, trapping moisture beneath the surface and thereby providing a moist environment where mold can grow on the wallboard or wood paneling underneath.

While all mold growth should be immediately addressed in the indoor environment, there are several types of mold that are of particular concern:


Stachybotrys atra, also known as Stachybotrys chartarum (SC), is regarded by the media and implicated by the public health community as a potentially dangerous toxic mold. S. chartarum is known to produce at least 170 different mycotoxins (poisons from a fungus), has been associated with several infant deaths, and was implicated in the $32 million Texas lawsuit. The mycotoxins produced by this fungus cause rashes, inflammation and hemorrhaging of the lung, and suppression of the immune system.


Aspergillus fumigatus is responsible for ailments from allergy-type illnesses to life-threatening generalized infections (aspergillosis). This mold grows in both the lungs and sinuses, threatening permanent lung damage (fibrosis) or even death. Aspergillus is of particular concern in hospitals and nursing homes as immuno-compromised individuals are much more susceptible to aspergillosis.

Other aspergillus species (i.e. A. flavus, A. clavatus, and A. parasiticus) also produce mycotoxins. These mycotoxins may be carcinogenic, affect the liver, kidneys, and basic cellular functions. Some of these toxins commonly contaminate grains and are heat stable so they survive cooking.


Some species of Penicillium are known for their beneficial antibiotic effects (i.e. Penicillium chrysogenum). However, a number of species (i.e. P. crustoum, P. expansum, and P. griseofulvum) grow indoors and produce very dangerous mycotoxins. These mycotoxins may be carcinogenic and affect the liver, kidneys, and nervous system, posing a serious threat to human health.

Many more types of mold grow indoors with the potential to produce harmful effects, (e.g. Cladosporium, Fusarium, and Alternataria) especially in those individuals who are immuno-altered or immuno-compromised. Any indication of significant indoor mold growth warrants an investigation- for better health.