As a homeowner, one of the worse situations to have is a dangerous chemical spill of some type.  People infrequently think that moldy walls can be just such dangerous substance.  The causes of mold can range from damp, dank, and dark areas to outright mildew which grows without our knowledge.  This is not the normal mold that we see on old bread or cheese.  This green smelly mold is different from the dark, toxic mold that grow between walls, under floors and on susceptible drywall.  Often in the basement, mold needs to to be torn out from the house and eliminated for the safety of the inhabitants.