Let me address the two issues in reverse order.
The biggest hoax is the hysteria over the notorious black mold that grows on sheetrock. This black mold is formally known as Stachybotrys chartarum or Stachybotrys atra. The horror stories related to items such as infant deaths in Cleveland in 1993 and 1994 are not true. The statements of CDC related to possible cause have been retracted by that Organization. With extremely rare exceptions (possibly only one documented case) there is no association between inhalation of Stachybotrys chartarum and any identifiable disease.
It is true that Stachybotrys chartarum, as part of its metabolic processes, produces a chemical by-product called a mycotoxin. But there are hundreds, thousands, perhaps even tens of thousands of other molds that produce mycotoxins. Mycotoxins are large molecules that do not easily become airborne, thus the only real possible exposure is ingestion such as eating grains or other foodstuff with a large growth of Stachybotrys or direct infection through an open wound.
The possibility that a person who is not severely ill, or whose immune system is not compromised from disease or suppressant medicines, exhibiting any reaction to a mycotoxin is practically nonexistent as shown by the total lack of scientific evidence showing a direct link between a specific mycotoxin and any disease or symptom.
The large and numerous claims paid to homeowners, tenants, and building occupants have little, if any scientific basis.
Why hasn't the scientific community created a storm of protest? Why hasn't the scientific community published scientific evidence to the contrary?
Unfortunately, science does not respond well to hysteria and news coverage. Just as in medical testing, the process takes years – 5 or 10 or more years, to develop clear scientific evidence. Further the process is expensive and there are no marketable “wonder drugs” to offer to the marketplace to offset the cost. Thus the government is usually the primary source of funds. But Stachybotrys must compete with AIDS, cancer, heart disease, TB and a thousand other priorities for the research funds.
Of late, the insurance companies have had to pay the mold claims and may be a source of funds except that the fact that their current response is to exclude mold from their insurance coverages.
Why have so many claims been successful? Because the courts recognize “proving a negative”, that is, “it isn't anything else so it must be Stachybotrys”! There is no such thing in science. You have to prove there is no direct link between Stachybotrys, the mycotoxin, and a specific effect on a human being. This may take years and studies costing millions of dollars. Further, one study showing a link is not sufficient, it must be proven by additional studies confirming the first test used proper and scientific methodology and reached appropriate conclusions.
Are molds a hazard? Yes, they are! Mold can adversely affect humans. Its clear from information, as summarized by the Institutes of Medicine in a 2003 report that 1 in 5 humans has some allergic response to their environment and 1 in 10 are allergic to some form of mold/fungus and likely some smaller number do react to chemical by-products of mold growth but probably less than one in a hundred (and in most cases due to some special situation such as infection, ingestion, or a compromised immune system). Creating the proper environment of food, temperature and moisture is all that is needed to start the rapid propagation of these microbes. Molds can create or aggravate allergies, asthma or other respiratory ailments to lessen quality of our lives.
Molds do not magically incarnate themselves when the right conditions are present, but are everywhere – in small numbers- waiting for the right conditions so they can rapidly multiply. Our primary goal must be to prevent these optimum conditions.
The easiest and most successful control is to eliminate moisture. Most molds, especially those that adversely affect us, require high moisture i.e. 70, 80, 90 or 100% humidity. Controlling moisture in our homes, offices, and other dwellings is the most successful prevention strategy.
Further, even after a mold infestation, is it rarely, if ever, necessary to knock the building down and start over. Mold can be washed off most solid surfaces and generally cleaned off semi-porous surfaces. Use of biocides and fungicidal paints can suppress mold growth even where moisture control is not feasible (such as in damp humid climates). Laundering of porous materials such as clothes and curtains will wash off most molds – just remember that we can't truly eliminate them since they are ubiquitous. In fact, in most cases the determination to demolish or discard a material or object is generally based on the water damage or whether the cleaning will destroy it sufficiently that it cannot maintain its normal use, integrity or appearance.
In conclusion, in our modern controlled environments in home, office and public buildings, and the proper combination of heat, moisture and a food source will spark rapid growth of mold creating a possible allergic reaction in some individuals but rarely creating any toxic hazard.