Is mold dangerous to people?

Health effects from mold exposure occur due to the presence of spores, mold toxins (mycotoxins), microbial volatile organic compounds (mVOC's), and glucans or fungal cell wall fragments.

Spores, as indicated above, are the "seeds" that allow mold to reproduce. Some spores are readily airborne, while others cling to surfaces only to be removed through direct contact or disturbances. Predominately mold spores are associated with allergic reactions or the exacerbation of asthmatic symptoms. Spores may pose potential allergic reactions whether they are viable (able to grow) or non-viable (dead). 

Mold Toxins are found residing on and within mold spores. Not all molds produce toxins, and some only given certain environmental conditions. There is abundant evidence that ingestion of mold toxins (like eating moldy bread) is harmful to human health, but there is limited information about inhaling or touching mold toxins. The most dangerous mold toxins are generally NOT found in building structures, but rather found on moldy food stuffs like contaminated grains and peanuts. Just because there is mold present, doesn't necessarily mean that mold toxins are present. Health problems associated with mold toxins are reported to include mucous membrane irritation, skin rash, nausea, immune system suppression, acute or chronic liver damage, acute or chronic central nervous system damage, endocrine effects, and cancer. More studies are needed to get a clear picture of the health effects related to most mycotoxins. However, it is clearly prudent to avoid exposure to molds and mycotoxins.

Microbial Volatile Organic Compounds are the musty or "earthy" odors associated with mold growth. Generally mVOC's alert you to the presence of significant mold growth in an area or environment. There is limited research on the health effects associated with mVOC's, although it is reported that they can cause headaches, nasal congestion, dizziness, fatigue and nausea.

Glucans or fungal cell wall fragments are the parts and pieces of mold that has died or been decomposed. High amounts of glucan exposure can effect the immune system and even lead to Organic Toxic Dust Syndrome which is a flu-like illness. This along with many of the other health problems attributed to mold can be found predominately in agricultural and manufacturing settings.