Indoors, mold becomes a problem when spores land on a damp spot and begin growing. Because molds produce allergens and irritants, inhaling or touching mold or mold spores may cause allergic reactions anywhere in the body and/or irritate areas that experienced direct contact. 


Reactions to mold are common, and can be immediate or delayed. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash. Common signs of irritation include discomfort in the eyes, nose, throat, lungs, and on the skin. In addition, mold can trigger asthma attacks.

Additional Information

This page does not describe all potential health effects related to mold exposure. For more detailed information consult a health professional, your state or local health department, or the Center for Disease Control & Prevention



Radon is a radioactive decay product from the element uranium, a material found deep underground all over the world. Because radon is a gas, it seeps upward, emanating from rocks and soils, and tends to concentrate in enclosed spaces such as mines and houses. Referred to as "soil gas infiltration", this process is recognized as the most signficatant source of residential radon - our sources being water supply, building materials, etc.

Studies on indoor radon and lung cancer in Europe and North America have concluded that radon is the second-leading cause of lung cancer after smoking.  The analyses indicate that length of radon exposure is more significant than concentration level of exposure. Especially important to the homeowner, this means that years of low-level radon exposure elevates cancer risk more than shorter exposures of higher concentrations.

Additional Information

The EPA strongly urges remediation or action be taken in homes with a radon level at or above 4pCi/L (picocuries per liter) to reduced exposure.