Mold Stachybotrys chartarum, a type of greenish-black mold that requires significant water damage in order to grow

Molds: Stachybotrys chartarum (atra)

Molds are very common in buildings and homes and will grow anywhere indoors where there is moisture (see Mold & Moisture). A quick review of mold conditions is available from EPA weblink (PDF).

Although a common mold in the United States, Stachybotrys chartarum (atra) is unusual in homes. The most common indoor molds are Cladosporium, Penicillium, Aspergillus, and Alternaria.  The CDC does not have precise information about how often Stachybotrys chartarum is found in buildings and homes (Source CDC, Q&A Molds 2004). While it is less common than other mold species, it is not rare

There are about 15 different species that of Stachybotrys worldwide. The mold lives on moist and water logged wood and paper. In homes it can grow in wallpaper, thermal insulation, fiberboard, dry wall, and gypsum board. The mold does not like to grow on plastic, vinyl, or shower tiles. The mold is relatively slow growing and other rapidly growing fungi can displace it.

In building material Stachybotrys grows best when the humidity is above 55% and there are rapid temperature fluctuations. When wet the mold is as a slimy green-black often with white edges, but when dry it appears as black spots. If the mold takes over an area greater than several square feet often with extensive water damage or involves structural materials, a contractor familiar with mold clean-up will be needed.

Why is mold growing in my area?

Molds are part of the natural environment.  Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, mold growth should be avoided.  Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air.  Mold may begin growing indoors when mold spores land on surfaces that are wet.  There are many types of mold, and none of them will grow without water or moisture (source: EPA website - Mold Basic)

What are the potential health effects of mold in buildings and homes?

Mold exposure does not always present a health problem indoors. However some people are sensitive to molds. These people may experience symptoms such as nasal stuffiness, eye irritation, wheezing, or skin irritation when exposed to molds. Some people may have more severe reactions to molds. Severe reactions may occur among workers exposed to large amounts of molds in occupational settings, such as farmers working around moldy hay.

Severe reactions may include fever and shortness of breath. Immunocompromised persons and persons with chronic lung diseases like COPD are at increased risk for opportunistic infections and may develop fungal infections in their lungs (source: CDC website).

The mold issue can be a concern in locations which have experienced flooding as well as water leaks due to plumbing failures, condensation, storms and accidents. Currently EPA has set no strict regulations for determining the health risks associated with Stachybotrys.

How do you get the molds out of buildings, including homes, schools, and places of employment?

In most cases mold can be removed from hard surfaces by a thorough cleaning with commercial products, soap and water, or a bleach solution of no more than 1 cup of bleach in 1 gallon of water. Absorbent or porous materials like ceiling tiles, drywall, and carpet may have to be thrown away if they become moldy. If you have an extensive amount of mold and you do not think you can manage the cleanup on your own, you may want to contact a professional who has experience in cleaning mold in buildings and homes. It is important to properly clean and dry the area as you can still have an allergic reaction to parts of the dead mold and mold contamination may recur if there is still a source of moisture. Suggested readings from EPA, OSHA & CDC describing procedures & precautions for extensive mold clean up are at the following links:


In summary, Stachybotrys chartarum (Stachybotrys atra) and other molds may cause health symptoms that are nonspecific. At present there is no test that proves an association between Stachybotrys chartarum (Stachybotrys atra) and particular health symptoms. Individuals with persistent symptoms should see their physician. However, if Stachybotrys chartarum (Stachybotrys atra) or other molds are found in a building, prudent practice recommends that they be removed (source: CDC website).