Part I  -  The reality of mold.

       Mold is a construct of nature who's extended family includes mushrooms and yeasts. There are more than 100,000 known species of mold in the world and probably many times that number that have yet to be identified and properly cataloged.

       Most of us have eaten or otherwise enjoyed the benefits of mold, fungi, and yeasts.  Some mushrooms, for example, are edible and many tons are consumed worldwide on any given day.  Rising bread baked around the world will also be served thanks to the help of yeast.  Fermentation of beer and wine will also be made possible by yeast and the cheese on the table might not be there if not for mold.  Then there are the medical benefits; Penicillin alone saves thousands of lives each year worldwide as it cures infections that might otherwise prove deadly.

     That is the bright side of mold but mold also has a potential dark side.  Exposure to mold has been associated with everything from minor allergy symptoms to lethal opportunistic infections and illnesses in particularly vulnerable individuals.  While that may sound scary on its surface, we must take into consideration the true health concern regarding "minor allergy symptoms" and consider what is actually meant by the phrase "particularly vulnerable individuals".

       Minor allergy symptoms within the respiratory system might include sinus and nasal congestion (the sniffles and/or stuffiness), sneezing, watery eyes, cough and sore throat.  While these symptoms are no doubt irritating to anyone who has to endure them, they do not necessarily constitute a major health crisis for the sufferer.  Minor allergy symptoms beyond the respiratory system might include rashes, itching, and swelling.  While again  irritating, these are not a major health threat to the sufferer and treatment for such symptoms is readily available.  Many of us experience symptoms such as these on a daily basis and it should be kept in mind that mold is not always the culprit though it is certainly on the list of possible causes.  

     Before we get to the more serious potential health threat that mold might pose, lets mention a few of the common fungal infections that most of us have had (or will have) at some point during our lives.  Do any of these sound familiar; jock itch, athletes foot, vaginal/urinary yeast infections, yellowed toe and fingernails, thrush?  All of these are the result of common fungal infections and can usually be gotten rid of with the help of a doctor or by following the good advise of our neighborhood pharmacist. 

       Now lets talk about the "particularly vulnerable individuals" who might experience serious to potentially life threatening fungal infections and/or diseases.  What exactly does "particularly vulnerable" mean?  Simply put, they are those among us who are most vulnerable to disease and infection.  Common sense and our physicians would tell us that this group includes; infants (because their immune systems have not yet fully developed), the elderly (because their immune systems are not what they once were), and others who happen to be immuno compromised including those undergoing chemotherapy, those on immuno suppressing drugs (organ transplant patients for example), acquired immune deficiency syndrome (AIDS) patients, and those who's bodies are already struggling to overcome other diseases, infections, or serious injuries.

       These are the individuals who are most subject to opportunistic infection and disease be it fungal related or otherwise.  A few commonly recognized opportunistic fungal infections include Aspergillosis, Candidiasis, Coccidiodomycosis, Cryptococcal Meningitis, and Histoplasmosis.  Exposure to mold and mold spores may also aggravate existing conditions such as pneumonia and asthma taking these and other illnesses to more serious levels.  There is also the risk that some individuals will become sensitized to mold after repeated or heavy exposure and may have a sudden and serious allergic reaction.

       Some occupations can bring about potentially heavy exposure to mold and mold spores.  Conditions known as Mushroom Picker's Disease, Farmer's Lung, and Bird Breeder's Lung are all mold related illnesses that may manifests in Hypersensitivity Pneumonitis/Alveolitis or perhaps one of the other conditions mentioned above.  Some within the cheese making industry have also fallen ill to heavy exposure to the generally benign molds involved in the cheese making process.  It should be understood that occupational exposure to mold would typically be considered heavy or extreme when compared to typical outdoor or "normal" indoor exposure levels found in a typical residential setting. 

Mold In The Home

       Much has been said regarding mold in our homes over the last few years (particularly within the courts). One might be lead to the conclusion that mold in our dwellings is a relatively new phenomenon or that the presence of mold there had only recently been discovered. The fact is, mold has been around much longer than the human race and we have, no doubt, been dealing with it in our dwellings since the first grass hut or pile of sticks and hides was assembled by the first 'construction engineers'.

       Obviously human exposure to mold is not a new phenomenon.  Humans and mold have always lived side by side and probably always will.  Like it or not, mold is everywhere and that includes our homes. Even though some mold will always be present, be it seen or unseen, we should never allow mold to develop and grow unchecked in our home. The appearance of mold should be taken seriously and steps should always be taken to remove it from the indoor environment and to remedy its underlying cause (more about this later).            

How much is too much?

       How much of what types of mold will ultimately prove to be unhealthy is a very difficult question for science to answer. I personally do not hold out much hope for a legitimate answer any time soon.  In fact, I am not sure that a "legitimate" answer will ever be found considering the complexity of the question.

       Consider the many tens of thousands of mold species that exists and all the possible human responses as well as all the varying and transient levels of human vulnerability; throw into that mind numbing mix that fact that a given colony of mold may (or may not) be producing a variety of potentially harmful chemicals called mycotoxins, and we can begin to grasp the enormous complexity of the task of determining "how much is too much".  The variables mentioned above are but a few that need to be taken into consideration. There are other equally daunting variables that concern the potential cumulative affects when different mold species are present together in the indoor environment.  Even the food source upon which the mold is feeding will affect its potential for mycotoxin production. 

       Ultimately, any "legitimate" exposure limits that might be offered would likely be amended the following day by the next "legitimate" exposure limit base on a different set of criteria drawn from the same pool of near infinite possibilities.  It is precisely because of this complexity that there are currently no universally accepted human exposure limits for mold and mold spores as exist for other recognized environmental health hazards such as lead, asbestos, and radon gas.

       What's more, the health community's understanding about how humans might actually be exposed to high concentrations of mold spores and mycotoxins in the home remains incomplete.  This is true even in cases when the presence of growing mold has been verified by both visual inspection and laboratory testing.  Not only do we not know how much mold exposure would be 'too much', but we also remain generally ignorant of how much exposure is actually taking place even when mold is known to be present.

       Work within the science community is ongoing but a good body of data from which to draw meaningful conclusions has yet to be amassed. Because of this, conclusions drawn from such data as does exists are often called into question. The scientific validity of one study, linking pulmonary hemorrhaging in infants exposed to the mycotoxin producing Stachybotrys Chartarum in Cleveland (1994), for instance, was later called into question leaving the topic open for much debate and further study.  Even the medical evidence presented during the famous Ballard vs. Farmers Insurance case in Texas was ultimately thrown out because the experts themselves were in discord.  The Ballards ultimately won their case based on demonstrated bad faith on the part of Farmers Insurance and not on a successful claim of personal injury due to mold exposure.   

Current state of affairs.

       Obviously, many unknowns remain and this uncertainty has consequences that go beyond the potential human harm that exposure to mold might create. Trial lawyers for example are having a field day arguing in and around all of the uncertainties to the expense of all. Insurance companies have suffered great losses that will have to be made up by the policy holders to whom all expenses are ultimately passed. And lastly, Government is taking its first clumsy steps to try and save us, not only from mold, but from each other as well.  State licensing in Texas for mold related activities is now a reality and mold inspectors, remediators, and testing labs will be required to be licensed by the Texas Department of Health beginning January 1st of 2005.

Although licensing is certainly a step in the right direction, our society currently finds itself in the troubled waters that lie between the bliss of ignorance and the joy of enlightenment regarding mold contamination and human health. How long we will continue to flounder in this unenviable position remains to be seen. It would appear however that we will be in for a rough ride for some time to come. 

Part II  -  Fighting mold in the indoor environment.

       Even though the medical, legal, and governmental communities will no doubt continue to debate the potential health threat of mold far into the future, there is no debate that mold is a destructive organism to the home itself and that its presence is a sign of trouble that must be addressed.  One of the major rolls that mold plays in nature is to process and break down organic materials.  Since our homes tend to be made mostly of organic materials, mold may be considered to be naturally destructive to our homes.   

       The task of keeping mold out of the home begins with the construction community.  The construction community I speak of includes all of those that we depend upon to design, build, and maintain our homes.  This included architects, construction engineers, builders, general contractors, remodelers, roofers, plumbers, HVAC contractors, as well as all related product and systems manufacturers.  

      In order for our homes to remain healthy and fit to live in, they must be properly designed, properly constructed, well maintained, and kept clean. While the task of keeping mold out of the home begins with the construction community, it ultimately becomes the responsibility of the homeowner to keep up with essential maintenance and cleaning duties.

       Unfortunately, the chain of design, construction, maintenance, and housekeeping  often gets broken somewhere along the way and the result can be mold development in the home.  Whenever visible mold is present in the home it indicates a problem and a need for action.  Mold should always be eliminated from the indoor environment regardless of its debated potential for human exposure or harm.  Further, the conditions that have allowed the mold to develop in the first place must be addressed.  Conditions that are conducive to mold development should also be eliminated in order to preempt potential mold problems. An ounce of prevention is truly worth a pound of cure.

       Correcting minor mold problems need not be expensive and sometimes involves little more than stepping up housekeeping duties and changing a few habits. Serious mold problems however can be expensive to correct and the best way to avoid the expense is to avoid the problem.

Basic ingredients of a mold problem.

       Three things are needed to create a mold contamination problem in the home. The first ingredient is mold spores. Mold spores are not visible to the naked eye and are, in essence, microscopic seeds floating on the air currents waiting to be deposited in a suitable environment so that they can grow into a colony.

       Because mold spores are prevalent outdoors, they are also going to be present in the indoor environment. The normal exchange between indoor and outdoor air guarantees that some mold spores will enter the home. That mold spores are present in the indoor environment is not surprising nor is it generally a cause for concern so long as the spore count and species makeup remains consistent with the ambient conditions encountered outdoors. With good housekeeping and good HVAC filtration, we can typically keep the indoor spore count below the levels encountered outdoors on a given day.

       The presence of mold spores however is only one third a potential mold contamination equation. Another third of the equation is the presence of a food source for the mold. The bulk of materials that we use to build and furnish our homes is made from organic material. Our homes are quite literally made out of mold food.

       The final third of the mold contamination equation is moisture. Add sufficient moisture to the mix of spores and food sources, and conditions will be ripe for mold development in the indoor environment. The needed moisture can come from a variety of sources be it a leaky roof or plumbing pipe, high humidity levels created by improperly functioning HVAC system, condensation caused by temperature differentials, or even water incursion due to poor grading and drainage around the property. There are numerous possibilities for moisture penetration and generation in and around the home and detecting hidden moisture problems can be a difficult task.  This is particularly true when the root cause is a design or hidden construction defect.

       Lets take a look at the three part equation:

Mold Spores + Food Source + Moisture = Eventual Mold Development

       Notice the word "eventual" in the equation? Time can be considered to be a fourth ingredient but it is actually more of an inescapable modifier to the equation. It does not take much time for mold to begin to grow when spores, food, and moisture are brought together under the right conditions. Visible growth can be seen in as little as 24 to 48 hours although it can take longer depending on conditions such as: how processed the food source is to begin with, how much moisture is available, what types of mold spores are present, and how favorable the temperature is for those particular species. Rest assured however, if the all three of the key ingredients of the equation are allowed to come together in our home, mold growth will occur. Its just a matter of time.

       Although time will eventually work against us, any delay of onset can give us a window of opportunity to break up the equation before a serious mold contamination problem can develop. In order to break up the equation however, we must address one or more of the key ingredients in a timely manner. If we can remove, or sufficiently alter, any of the three key ingredients, we have hope of stopping mold before it develops.

Where do we attack the problem?

       Mold Spores   Frankly, we can do little to keep all mold spores out of our home and it is just not practical to try and turn our home into a hospital clean room. We need air exchange between the indoors and out and even though we can control and filter that air exchange, we cannot in any practical way prevent the entry of all mold spores. Some viable mold spores will get into the indoor environment even if we carry them into the home on our skin and clothing as we come and go.

       Food Source   Eliminating the food sources from the equation is almost as difficult as trying to eliminate the mold spores themselves.  How do we eliminate all wood based products and other organic materials from our homes? We could reduce the use of such products but that would require a fundamental shift in the way the construction industry currently builds. Also, from a practicality standpoint, we cannot afford to rebuild all of the existing buildings that already have such food sources already incorporated into the structure. Even if we were to significantly reduce or eliminate the potential food sources in construction, there would still be those food sources that we would bring into the home as a matter of day to day living; wood furniture, rugs, clothes, books, and leather goods for example. All of these and more are potential food sources for mold.

       Moisture   Our final hope in breaking up the equation and controlling mold lies in controlling moisture. Some measure of assistance in controlling moisture is granted us by the window of opportunity inherent in the time modifier within the mold contamination equation. If we keep things sufficiently dry from the outset, the clock never begins to tick against us and the equation will remain incomplete for want of its moisture component. If we should suddenly lose control over moisture, but can respond quickly enough to regain control, we might well be able to remove the moisture component of the equation in a timely enough manner to avoid an ensuing mold contamination problem. 

       Controlling moisture both before and after the mold contamination equation comes together is the key to controlling mold and requires effort on a number of fronts. It begins with good home design which requires follow through during construction.  Our homes must be designed and built to stay dry and be free of defects that can allow moisture to accumulate.  After proper design and construction, the property owner must be vigilant about upkeep, routine maintenance, cleaning, and rapid response to sudden moisture events.  To ignore these responsibilities is to invite a mold contamination problem into the home.  

       Although all moisture problems may not become mold problems, its important to remember that all mold problems are moisture related!