Mold has three forms is its lifecycle.  It can be an active and alive fungus, which lives on water and cellulose, such as that found in drywall.  Once established through water intrusion it eats and grows to a density of about 250,000 mold colonies per square foot. As it grows it also starts to reproduce by forming spores.  Spores are not technically considered alive.  However with the addition of water the spores can blossom into molds and restart the growth cycle.  Spores have been shown to be viable (meaning they can form living mold again) as old as 2 million years!  Spores are very tiny and very easy to inhale through the lungs directly into the bloodstream, causing symptoms within 20 minutes.

Spores can also secrete a deadly toxin known as mycotoxins.  The purpose of the mycotoxins appears to be the molds own biodefense weapon used to kill its natural predators- other molds. However the mycotoxins are also deadly to humans, and are believed to have been used as the biowarfare weapon yellow rain.

So for the math:

Consider 250,000 colonies mold/square foot. Each colony can produce about a 1000 spores, and each spore can produce about 100 mycotoxins.  Therefore a square foot of mold growing in a home could produce on the average about  2.5 ^11 molecules of mycotoxins per square foot!!  A  99.99 percent removal would still leave about 250,000 molecules of toxin to be spewn about everywhere!   Now you can understand how hard it can be to remediate a house after a flood, especially since mold starts growing about 2 days after water intrusion.

The Arizona Department of Health has published a very informative article on the lethality of trichothecene mycotoxins as a possible biowarfare weapon.  Trichothecenes are the mycotoxins produced by Stachybotrys, popularly known as black mold. However Arizona believes that the only source of exposure to this deadly mycotoxin would be through contaminated food or bio warfare.  It does not appear to recognize that exposure to Stachybotrys growing in a  citizen’s flooded bathroom or under their leaking sink would be a more likely source of exposure to the deadly mycotoxin.  Please click on the link below to read this document.

Trichothecene Mycotoxin – Arizona Department of Health Services