Frequently Asked Questions

     More about Mold FAQs...

     How should a building be evaluated for mold?

   Check building materials and spaces for visible mold

   Assess moisture – water leaks, high humidity, and/or condensation

   Consider occupant complaints

   Check for HVAC system involvement, condensate pans, air pathways, and mold on or around air diffuser

     When is sampling necessary?

 In cases of health concerns, litigation or when the source of contamination is unclear, sampling should be considered as part of the building evaluation

 Sampling may not be necessary, if visible mold is present, it should be remediated by a qualified contractor.

   If mold is present but not visually detectable, sampling may reveal evidence of mold amplification or reservoirs indoors

   Air sampling can indicate whether the mix of molds is typical or atypical, or unusual in concentration

   Using a certified industrial hygienist and an accredited lab is essential, and the sampling should be done in an effort to answer a specific question about the building

      Why is there controversy about the health effects of
      exposure to mold growth?

   Not all health effects are controversial. Fungal infections and allergies are well known.

   These effects can be measured and reproducibly demonstrated.

   The clinical relevance of mycotoxin exposure under realistic exposure levels is not fully established.

   Current supporting evidence is based on case studies rather than controlled studies.

   The studies that have been done have not yet been reproduced and some of the symptoms are subjective and difficult to quantify.

   The controversy is intensified since the health effects attributed to mycotoxins are often serious and sometimes claimed to be permanent.

In summary, mold growth in the built environment should be considered unacceptable from the perspectives of health effects and building performance.

Why are there no standards for mold exposure?

Health hazards of exposure to environmental molds relate to four broad categories of chemical/biological attributes of molds and their metabolites.

   Classified as: 1) irritants, 2) allergens, 3) toxins, and rarely
4) pathogens. Different mold species may be more or less hazardous with respect to any and all of these categories.

   Risks from exposure to a particular mold species may vary depending on a number of factors, primarily, each individual’s sensitivity can be widely different. As an example, if you are allergic to penicillin, you are allergic to mold.

   Exposure standards may not ever be established, and it is uncertain which governmental agency may do so.

With no standards, how do I interpret my sampling results?

   Comparing the kinds and levels of organisms detected in different environments is a useful method.

   Usual comparisons are indoor to outdoor, and complaint areas to non-complaint areas. In buildings without mold problems the qualitative diversity of airborne fungi indoors and outdoors should be similar.

   Some fungi, when found over and above background levels, are strong indicators for a moisture problem with a building related source that should be addressed.

Does mold remediation always require isolation/ containment?

   Yes, mold remediation should always require some level of isolation of materials or containment.

   Local area or full containment decisions can be made based on the potential for occupant exposure or building contamination.

   The decisions should NOT be made based on the SIZE of the affected area. There can be one million mold spores in a one square inch area of affected porous material. It is the dispersion of these spores that needs to be controlled (contained).

Are biocides required or useful in remediation projects?

   In most remediations biocides are not a substitute for the removal of the affected building materials.

   Mold spores have metabolites present that are secreted into the materials upon which mold has grown. The application of biocides may kill mold spores, but it does not necessarily eliminate these metabolites.

   Treating an active mold growth site with the above mentioned spore density (one million spores in a square inch) with a biocide that has effectiveness of 99.999% would leave an estimated 10 viable spores per square inch. If the underlying moisture problem is not resolved, mold growth may re-occur.

What are the gaps in our knowledge about mold exposure and the health effects of mold exposure?

   Chief among our knowledge gaps are (1) defining how mycotoxins affect human health and (2) the health risks associated with mycotoxin, microbial volatile organic compound, allergen, and glucan exposures, particularly the proposed response to Stachybotrys mycotoxins associated with hemosiderosis.

   Until microbiological methods for demonstrating mold concentrations in the environment are standardized, epidemiological studies necessary to determine dose- response can only suggest association, not cause and effect.