Mold is a type of fungus. It is present almost everywhere, including the air. In general, normal amounts of mold in the environment do not pose a substantial health risk to healthy people with regular immune system function. There is no single type of mold called “black mold” — many molds are black. When people use the term, they may be referring to a type called Stachybotrys chartarum (S. chartarum), also known as Stachybotrys atra.There is no scientific evidence to suggest that exposure to S. chartarum is more dangerous than exposure to any other type of mold. However, some people may be more sensitive to mold spores than others, and they may develop respiratory symptoms after inhaling even a small number of spores. In large quantities, mold spores can cause ill health in almost anyone. Therefore, people should remove any mold growth in the home and take steps to prevent it from growing back.There is a commonly held belief that black mold — sometimes called toxic mold — can cause severe health problems because it releases mycotoxins. Mycotoxins are toxic substances that a fungus produces.Some research suggests that mycotoxins from S. chartarum have a link to serious health problems in people who live in contaminated buildings.