Not all mould that appears black or dark is of the deadly variety. There are four varieties of mould that are found in homes: one is deadly; the other three will only create an allergic or respiratory reaction in humans (depending on their tolerance / respiratory health, of course). It is quite easy to rule out the deadly variety and allay fears that fleeing one's home is necessary. Deadly mould (Stachybotrys) has received a good deal of media attention of late; it is important to note that it only grows where there is standing water, and there will typically only be standing water in the case of a flood that has not been contained or a leak (detected or undetected). The other three common indoor varieties of mould are: Cladosporium, Penicillium, and Aspergillus (some sources, i.e.: WHO) add Alternaria to this list, but in the thousand attics that we have tested and successfully treated, this has not presented as significant). Exposure to the above three moulds (Clad, Pen & Asp) which require only moisture to take hold, can be unsettling, but once the moisture imbalance has been corrected and the mould truly killed (and please be careful navigating this unregulated profession), the home can again become your safe haven.