We here at AQC often get calls from people looking for second opinions regarding information they’ve been provided or found on the internet regarding the effects of mold and required actions.  Misinformation regarding mold is rampant within the industry, generally given by charlatans, scare-mongers and profit seekers. 
     Some recent calls have included people calling after having heard/read the following things.  Click on the question to receive the real answer, based upon peer reviewed science, and government and professional organization publications:

1. It’s a good thing we got here when we did – the mold hasn’t gotten toxic yet
    
2. We found toxic mold in your home – you need to evacuate now.
    
3. We found mold in your air handler.  Don’t you know how dangerous that is?  Haven’t you heard of Legionnaires Disease?
    
4. I am a licensed mold consultant/remediator
    
5. We found ____ mold.  That mold causes ____ disease. (we’ve heard several of these – insert mold species and disease)
    
6. Aspergillus causes cancer
    
7. (This one was downright offensive!!) We took a swab sample and sent it to the lab.  The results showed the presence of Stachybotrys in your office.  This mold is toxic.  We need to fog the office with a biocide and HEPA vacuum all exposed surfaces.  The contaminated material must be removed under full containment in accordance with EPA regulations.  (Before you click: know that the growth encompassed approximately one square inch of drywall under a leaking hose.  No mention was made regarding repair of the leak).
    
8. We recommend taking a sample to find out exactly what kind of mold it is, so it can be properly addressed.
    
9. After the contractor has finished, there must be no mold left behind.
    
10. The total measured inside spore concentration was less than the total outside concentration.  Everything is fine.
     
11. We need to get rid of ALL the mold here.
     
12. For final clearance, we need to make sure that any species found in an air sample collected inside must also be found in the air sample we collected outside.
     
13. This application will kill all mold.
     
14. Once applied, this chemical will ensure that mold never returns.
     
15. We recommend fogging with ozone.
     
16. The mold is dead.  We don’t need to do anything.
     
17. The mold is alive.  We need to kill it.
     
18. There’s mold on the wood trusses in your attic – the attic needs to be sterilized.

Answers:
 

1. Mold doesn’t “get toxic”.  General misconceptions abound as to what types of mold can be considered “toxic”, however; a general rule of thumb is that in the normal indoor environment, healthy individuals are only likely to suffer allergic response to molds to which they are sensitive.  The term “toxic mold” refers to mold species capable of generating unhealthy chemicals (MVOC).  These chemicals generally have require a specific, high total concentration in the air before the chemicals can cause the documented health effects.  Such concentrations can be generated in the lab, but are rarely found in any but the most heavily gross contaminated areas.
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2. Evacuation is rarely necessary, and should never be recommended by a contractor or consultant, but rather should be the purview of a medical doctor.  Do you need to evacuate?  Certainly not unless someone has exhibited a health response to the mold present, as determined by your family physician or allergist.
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3. Legionnaires Disease is caused by a bacterium (legionella pneumophila), not a mold.  Furthermore, it is generally a water-borne contaminant that only becomes airborne when sprayed or aerosolized.  Additionally, virtually all air handlers normally have some mold growth in them.  A realistic approach should be used when deciding whether the growth is abnormal and requires abatement.
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4. Currently, only the State of Texas licenses mold contractors or consultants.  Although the Florida legislature passed a similar law in early 2005, it was vetoed by Governor Jeb Bush and did not become law.  The best way to select a contractor or consultant for mold-related work is to obtain and check references and to see that they have “MOLD-SPECIFIC” liability insurance (see published article on selecting a consultant or contractor on this web-site.  Such coverage can only be obtained by companies able to show proof of training and experience.
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5. Mold is rarely found to cause any disease within normal, healthy humans, and it is questionable whether such disease is likely to be associated with the levels found in indoor exposures to mold.  Those with compromised immune systems (such as advanced AIDS, chemotherapy or organ transplant patients) may be at risk for mold-related diseases, but healthy people generally are not.
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6. Aspergillus flavus (one of hundreds of documented species of Aspergillus) has been shown to generate a chemical called Aflatoxin B-1.  While it is true that this chemical is a known carcinogen, most mold experts, medical researchers and health professionals doubt whether enough of the chemical can be generated by the mold in an indoor contamination to result in the onset of cancer in humans.  No such case has ever been proven.
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7. There is pretty much nothing correct in this person’s sampling methodology, information or recommendations.  The sheer volume of faults within this statement would require several pages of response on this site.  Call us, and we’ll be happy to discuss it with you (813) 571-9788.
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8. The exact nature of the mold genus or species is rarely important.  Virtually all molds are capable of causing the same allergic response in those humans who are personally sensitive to them.
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9. Molds are ubiquitous (everywhere) in the environment.  Without them, life as we know it would quickly come to a complete end. Attempting to generate and maintain a sterile environment is nearly impossible, hugely cost prohibitive, and possibly unhealthy.
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10. It is not sufficient to simply look at broad numbers to define an environment.  The consultant must also look at the individual species that make up the findings within the sample to determine what the results mean.  Here in the US, in the summertime, it is not unusual to get outdoor spore concentrations exceeding 50,000 s/m³ (generally primarily Basidiospores (the common mushroom)) Findings in the indoor environment of 35,000 s/m³ consisting primarily of Stachybotrys and Chaetomium spores, although lower than outside, are a likely measure of gross contamination.  Also, it should be noted that air sampling alone is an inefficient and potentially misleading way of evaluating the indoor environment.  Thorough visual inspection and moisture survey are also critical and necessary components of an evaluation.
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11. Virtually all structures will have some mold content somewhere.  The goal of abatement should be to remove the gross contamination and to prevent future water intrusion to ensure that no more growth occurs.  A sterile environment will no longer be sterile as soon as the first door is opened to enter or exit.
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12. Although a generally good concept, these practices must include the addition of some common sense.  All indoor molds can be found in the outdoor environment.  Therefore, a single structure of a mold genus founding an indoor sample shouldn’t be taken to mean that contamination still exists there.  If you didn’t find that one structure outdoors, that simply indicates that you didn’t take enough outdoor samples.  The structure didn’t evolve in the room, it came from somewhere.
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13. Biocide use in the indoor environment is generally unnecessary and/or a bad idea.  Many biocides are chemicals that can also be hazardous to human health.  Several have been shown to be more harmful to people than to the molds they are used to destroy (such as ozone – See FAQ #15).  There is currently no known commercially available chemical proven to kill all molds. (Also - see FAQ #17)
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14. Many commercially available microbial inhibitor applications will offer a guarantee of no mold returning……”provided that no additional water intrusion occurs and that the indoor relative humidity remains within acceptable ranges”.  In the event that water intrusion continues, no inhibitor will work for long.  If the water intrusion ceases to occur, then why would one need to apply an inhibitor?
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15. Ozone has been proven to be a strong respiratory irritant in humans.  It has not been shown to have as much effect on molds.  Ozone should NOT be used in mold abatement projects.  Period!!!
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16. Dead mold may be just as detrimental to health as live mold (see FAQ #17).  Also, regardless of what biocide was used or the situation in which the mold “death” occurred, it is extremely unlikely that all the spores were killed.  A bit more water, and growth will return and expand exponentially. Visible growth should be removed regardless of its condition.
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17. Killing molds may not actually be helpful in most indoor environments.  The primary health issue with respect to mold in most environments is allergic response.  Allergic response has been shown to be caused by an antigen (protein) on the outside of the mold spore.  Alive or dead, this protein is still present, and can cause the same health effects.  Mold contamination must be removed, not necessarily killed.
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18. So called “lumberyard mold” is found in nearly every wood constructed home, office and building, everywhere.  It is there. It has been there. It will be there. It is generally harmless. Leave it alone and save your money, unless a water intrusion episode has allowed it to expand beyond its normal state.  As noted above – sterilization is unnecessary and generally cannot be maintained.
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