Mold Exposure

Adopted by the MIAQC Board of Directors on November 6, 2003


Mold is everywhere in the natural environment, both indoors and out, and it is not practical to avoid exposure. However, extensive attention is being given to the issue of mold in indoor environments. Local, State, and Federal legislative efforts, as well as private sector initiatives, are underway or are being implemented as a means to respond to increasing public concern for the health and safety of our indoor environments. The Maine Indoor Air Quality Council recommends consideration of the following issues during the development or implementation of any initiative designed to regulate or otherwise manage mold in indoor environments.


The Science of Mold and Health


Whereas: Scientific studies of inhalation (breathing) mold exposures in the indoor environment have documented the following health effects in susceptible individuals:


  • Simple irritant effects (itchy eyes, runny nose, headaches)
  • Allergies in susceptible individuals (It is not known in the general population how much exposure or for how long is required to cause allergy. 5-10% of the population may be mold allergic.)
  • Exacerbation of asthma (A link between mold and the development of asthma has not been established.)
  • Infections in individuals with suppressed immune systems (the molds that cause infection in healthy individuals are not typically found indoors.)

Serious health effects from inhalation exposure to mold in the indoor environment (e.g., toxic reactions, infectious diseases, and chronic irritation) have not been well characterized. Toxic effects of mold have only been demonstrated following experimental exposures in animal studies and studies involving ingestion (eating) of contaminated foods.


Therefore: Additional health research is needed to better characterize the nature and scope of the health effects caused by indoor exposure to certain, specific molds. Particular attention should be given to the possible role of mold in producing serious, short-term or long-term effects on respiratory, immune, and nervous systems.


Since the research to characterize the effect of mold on human health is not fully developed, it is prudent to take precautionary measures, where practical, to prevent the growth of mold in the indoor environment.


Controlling Mold in Indoor Environments:


Whereas: Mold needs moisture and a suitable substrate (food/host) in order to grow and survive. The primary means to minimize mold exposure is by controlling moisture. Moisture problems may occur in buildings as a result of water intrusion (water leakage through the roof, foundation, or walls), high relative humidity (causing condensation), internal plumbing leaks, or poor or inadequate housekeeping.


Therefore: Building codes and operations and maintenance plans should include criteria to minimize the potential for moisture-related problems in new or modified (renovated) buildings. These codes and plans should ensure that energy conservation measures do not have an adverse impact on fresh air ventilation, occupant thermal comfort, or on relative humidity.


Professional organizations involved with the assessment of indoor environments should develop standardized methods for the assessment and remediation of moisture problems in buildings. They should develop training (and possibly certification) programs that focus on moisture prevention and remediation.


More education should be provided to increase public awareness of moisture control measures and their relationship to mold growth in buildings.




MIAQC Policy Statement on the Health Basis for MIAQC Recommendations

MIAQC Best Practice Recommendation on Testing

ACOEM Evidence-based Statement on Health Effects Associated with Molds in the Indoor Environment

NYC DoH Guidelines for Assessment and Remediation of Mold in Buildings

ACGIH – Bioaerosols

“Fungi: Toxic Killers or Unavoidable Nuisances?” by Harriet A. Burge, Ph.D., Annals of Allergy, Asthma & Immunology 2001;87(Suppl): 52-56.

“Indoor Air Quality & Health, Does Fungal Contamination Play a Significant Role? Emil Bardana, MD, Immunology and Allergy Clinics of North America 23 (2003): 291-309

Questions and Answers on Stachybotrys chartarum and other Molds. CDC National Center for Environmental Health.

Molds in the Environment. CDC National Center for Environmental Health.

“Indoor Allergens: Assessing and Controlling Adverse Health Effects,” Institute of Medicine; Andrew M. Pope, Roy Patterson, and Harriet Burge, Editors. National Academy Press, 1993.

“Clearing the Air: Asthma & Indoor Exposures,” Institute of Medicine, National Academy Press, 2000,