Toxic White Mold

Mold is a natural and integral part of our ecosystem and is found in just about every climate in the world. When white mold is found inside the home, it is often a source of concern for residents who may worry about possible toxic effects.

Some types of white mold may be harmful with long-term exposure.

But toxicity of mold is primarily decided by overall health of the person and length of exposure, not the color of the mold. Some types of harmful mold will be present in a number of colors, including white.


Aspergillus is among the most widespread molds in the world. There are more than 160 species and three main colors -- brown, gray and white. This type of mold is commonly found in soil and is easily tracked into the home, where it may thrive in carpets and other fabrics. Some homes may experience lots of growth on Oriented Strand Board, a wood product commonly found in newer home construction. Most types of aspergillus are fairly harmless and will cause problems only in extremely sensitive individuals after prolonged exposure. If left unchecked, the more dangerous types may cause allergy-like symptoms, including itchiness, runny nose and sneezing. In some immune-compromised individuals, long-term exposure may cause infections in the respiratory tract and other systems.


There are more than 200 members of the Penicillium family, only a few of which can be considered toxic. It is a common type of mold that most often makes its home in rotting vegetation and wood products. Identifying the most common forms is easy, as it emits an unmistakable musty odor. Like with other mold varieties, Penicillium is mostly harmful when left unchecked and will cause problems only when exposure occurs over a long time, except in individuals with weakened immune systems. Common exposure symptoms resemble the flu or allergies and include sneezing, coughing and difficulty breathing. Colonies will usually start out white and often turn blue or green later in development.


Members of the Phytophthora species primarily affect plants and other living matter. It is a leading cause of plant disease in the United States and is most prevalent in periods of heavy rain but can still thrive in dew or foggy conditions. Colonies will first appear cottony and will usually emit a fermenting smell. As the colonies grow, they will turn brown and leathery. This mold is most often found around plants but is also prevalent in soil and will occasionally make it into the home. If exposure is long-term, coughing, headaches and respiratory problems may result.


Phomopsis is most often found in warm-weather southern states and is frequently found in soil and wood products outdoors. It is known to do severe damage to fruit, twigs and leaves, and may cause similar damage to wood inside the home. Once established, colonies will appear white and fluffy. Phomopsis does not usually cause severe infections in people, but long-term exposure may create respiratory issues and allergy-type symptoms, including coughing, runny nose and sneezing.